DRAFT
TE KUHA MINE
REHABILITATION MANAGEMENT PLAN
Version 2
February 2017
TABLE OF CONTENTS
Page
TABLE OF CONTENTS
2
LIST OF FIGURES
4
LIST OF TABLES
4
1.
INTRODUCTION
5
1.1
1.2
5
6
2.
3.
REHABILITATION GOALS AND OBJECTIVES
7
2.1
2.3
2.3
2.4
2.5
7
7
8
8
9
5.
Rehabilitation Goals
Objectives
Closure Criteria
Definition of Self-Sustaining
Cross Reference to other Management Plans
MINE PLANNING MATTERS
10
3.1
3.2
3.3
3.4
3.5
10
10
10
11
11
11
11
12
13
13
13
14
14
3.6
3.7
3.8
3.9
4.
Requirement for Rehabilitation Management Plan
Vegetation of the Te Kuha Mine Area
Introduction
Relevant Consent Conditions
Scheduling of Rehabilitation
Direct Transfer
Soil Management
3.5.1
Soil auditing
3.5.2.
Soil Volume
3.5.3
Soil Quality
3.5.4
Soil Usage
Vegetation Growth Rates and Colonisation
Climatic Influences
Slope and Aspect
Knowledge Gaps
REHABILITATION DESIGN
14
4.1
4.2
4.3
14
15
16
Introduction
Habitat Linkages, Varied Topography and Blending In
Direct Transfer of high priority ecosystems
PREFERRED REHABILITATION SPECIES AND METHODS
16
5.1
5.2
5.3
5.4
5.5
5.6
16
17
18
20
22
24
24
24
Rehabilitation Process
Identifying Material for Use in Rehabilitation
Rehabilitation Scheduling
Stripping and Salvage
Stockpiling
Direct Transfer and Revegetation
5.6.1
Direct Transfer
5.6.2
Revegetation Methods
5.7
5.8
5.9
5.10
5.11
6.
35
6.1
6.2
6.3
6.4
35
36
37
37
37
6.6
6.7
6.8
8.
27
27
27
28
29
29
31
31
31
32
32
33
WEEDS AND PESTS
6.5
7.
Rehabilitation Procedures for Specific Landforms
5.7.1
Haul Roads
Low Altitude Sites
Higher Altitude Sites
5.7.2
Decommissioning of the Haul Road AND ROM
5.7.3
Overburden Placement Area and Backfilled Pit
5.7.4
Soil Stockpiles
5.7.5
Stream Diversion Channels and Banks
Forest and Shrubland
Herbfields, Tarns and Banks of Streams
Boulders and Rock Piles
Propagation Nursery
Introduction
Key Weed Species
Objectives of Weed Control
Management Procedures
6.4.1
Weed Control
6.4.2
Preventing Establishment of New Weed Species
and Populations
6.4.3
Minimising the Spread of Weed Populations within
the Site
6.4.5
Weed Control
6.4.6
Monitoring
6.4.7
Closure Targets for Weed Species
Pest and Predator Control
6.5.1
Key Pest Species
6.5.2
Consultation and Reporting
Management Practices
6.6.1
Monitoring
6.6.2
Beech Masting
6.6.4
Wasp Monitoring
6.6.3
Biodiversity Outcome Monitoring
Intervention Triggers
6.7.1
Possums
6.7.2
Rats
6.7.3
Beech Masting
6.7.4
Wasp Densities
6.7.5
Biodiversity Outcomes
6.7.6
Rehabilitation
Integrated Predator Control Programme
6.8.1
Spatial and Temporal Integration
6.8.2
Control Methods
38
39
40
41
42
42
42
44
44
44
45
45
46
46
46
47
47
47
47
47
47
47
48
REHABILITATION MONITORING
49
7.1
7.2
49
50
Frequency and Timing of Monitoring
Intervention Triggers
RESPONSIBILITIES AND REPORTING
52
8.1
55
Rehabilitation Training Schedule
9.
REFERENCES
56
LIST OF FIGURES
Figure 1: Rehabilitation concept for Te Kuha Mine [to come]
15
Figure 2: The Te Kuha Biodiversity Enhancement Area
43
LIST OF TABLES
Table 1: Indicative topsoil stockpile management.
12
Table 2: Indicative areas disturbed (cumulative) and rehabilitated (increments)
each year excluding loadout facility area.
18
Table 3: Short term rehabilitation aims (at time=0, 3 months, one year and three
years) and intervention triggers for the main landform and vegetation
types at Te Kuha Mine, 50 m belt transects 2 m wide = 100 m2 plots.
51
APPENDICES
1
2
3
4
Resource Consent Conditions
Native species to be used in rehabilitation
Sample weed register
Five minute bird count method
Glossary Required?
1.
INTRODUCTION
1.1
Requirement for Rehabilitation Management Plan
This Rehabilitation Management Plan details the rehabilitation objectives, strategies and
procedures to be adopted during the operation of the Te Kuha mine and the post-mining
phase to ensure compliance with the conditions of the applicable resource consents and
access arrangement conditions (details XX). This plan also describes the management
measures proposed to achieve specified rehabilitation outcomes and the responsibilities
of those who are to undertake this role.
The resource consent conditions that relate to the rehabilitation of the Te Kuha Mine are
provided in Appendix 1. An indicative list of native species to be sourced from the
Ngakawau Ecological District and used in rehabilitation is provided as Appendix 2. Each
section of this plan begins with an overview of the resource consent condition being
addressed. This plan represents current (2017) thinking as to methodology based on the
mine plans presented in the assessment of environmental effects prepared for this
project, and will need to be updated with new information as it becomes available. In
particular, annual review of this plan will incorporate current mine schedules and mine
planning data as required.
This plan is set out as follows:
Section 2 sets out the goals and objectives of the Rehabilitation Management Plan
including reference ecosystems and landscape outcomes (both visual and ecosystem
level patterns and connections) and describes how this plan relates to other
management plans prepared for the site including the earthworks and sediment control
plans, the mine closure plan and individual species management plans.
Section 3 outlines the specific matters relating to rehabilitation which require monitoring
and management including soil volume and availability, soil and root zone
characteristics, vegetation growth rates in relation to the climate, habitat creation, slope
and aspect and work plan influences as well as ecological knowledge gaps (Rhytida
snails, bryophytes, lizards, plant species such as Metrosideros parkinsonii).
Section 4 sets out the rehabilitation design to provide habitat linkages, for direct
transfer, for bryophyte protection, for the reinstatement of the catchment divide and for
the provision of habitat for key species such as lizards and forest ringlet butterflies.
Section 5 describes the rehabilitation methods to be employed and the baseline
conditions (landforms, root zone profiles, surfaces and plant species) for each area to be
rehabilitated. This section also describes specific rehabilitation practices and describes
the rehabilitation procedures proposed for each final landform.
Section 6 describes the management of weed and pest species and targets for their
control.
Section 7 describes the rehabilitation monitoring, its use in adaptive management,
suggested ‘trigger levels for intervention’ and the remedial interventions.
Section 8 describes the responsibilities and training required, consultation undertaken
and reporting required.
Section 9 provides the references used in compiling this plan.
1.2
Vegetation of the Te Kuha Mine Area
The pre-mining (2015) vegetation in the Te Kuha Mine area can be characterised into
four main types: forest (including rimu/hard beech forest and mountain beech/yellowsilver pine – pink pine forest), shrubland (including manuka shrubland and yellow-silver
pine – manuka shrubland), herbfield and manuka – Dracophyllum rockland. The
characteristics of these can be summarised as follows:

Forest is located on the lower slopes of the Te Kuha ridgeline (between Nine
Mile Road and the proposed mine site), on deeper soils on the upper slopes
and on the eastern slopes of the ridgeline (above the Buller River). The forest
grades from taller forest on lower slopes to lower stature forest and shrubland
on the upper slopes. Forests are associated with the most fertile and deepest
soils. Some forest types provide habitats for bryophytes of conservation
interest.

Herbfields are located on shallow slopes with impeded drainage, particularly
near the ridgeline itself.

Manuka visually dominates the shrubland associations found on the shallower
soils and steeper slopes at higher altitudes, including both shrubland classes
and manuka – Dracophyllum rockland.

Manuka – Dracophyllum rockland includes a variable proportion of bare rock
and boulders. This habitat is particularly important for lizards, and also
provides habitat for some species of bryophytes.
On the mid and upper slopes these habitats are characteristically fine-grained; they
change from one to another over short distances, creating a complex mosaic. Together
they form an unbroken, almost weed-free area with high connectivity.
Mining requires removal of these habitat types and fragmentation of the landscape. A
plan is required for their timely and appropriate rehabilitation as required by resource
consent condition X. Consent condition X requires this rehabilitation plan to be reviewed
annually and provides for amendments to be made as a result of input from the Peer
Review Panel or Technical Advisory Group [TBC] and the results of monitoring or other
necessary actions identified in the Annual Work Plans. The Department of Conservation
is required to be consulted with regard to any proposed changes to this plan and any
amended versions are to be provided to the Consent Authorities.
Several different landforms will be created by the mining activity. These include lowland
infrastructure areas, backfilled overburden in the mine pits, temporary ex-pit soil stockpile
areas, road batter fill slopes and cut rock faces greater than 20 degrees; and permanent
road-side soil stockpiles. In addition, some adjacent areas, such as the water discharge
area, will not be stripped but are likely to be affected by mining activity. Each of these
habitat types and landforms will require different, yet coordinated, rehabilitation
approaches to achieve the target rehabilitation outcomes.
2.
REHABILITATION GOALS AND OBJECTIVES
2.1
Rehabilitation Goals
The goals of rehabilitation at Te Kuha are to:
i)
ii)
Minimise sediment loss within and from the site.
Maximise immediate reuse of materials (soil, stripped vegetation, direct
transfer vegetation, wilding and hand collected plants, logs, boulders and the
like) so as to maximise their rehabilitation potential.
Create a self-sustaining, representative, predominantly indigenous
vegetation cover on post mining landforms that re-establishes landscape
connectivity.
Ensure the secondary vegetation created comprises species typical of the
area.
Create topography which allows for establishment of a vegetation mosaic
which integrates visually with the surrounding vegetation as quickly as
practicable.
Include elements of the pre-mining vegetation mosaic and species
composition (including locally significant species) where this is realistically
achievable.
Create habitat for fauna (particularly roroa, Rhytida snails, lizards and forest
ringlet butterflies).
Achieve mine closure criteria within ten years after completion of initial
revegetation treatment at the site.
Achieve haul road closure criteria within 5 years of mine closure (this
necessarily occurs later).
iii)
iv)
v)
vi)
vii)
viii)
ix)
2.3
Objectives
The objectives of this Rehabilitation Management Plan are:
a.
b.
c.
d.
e.
f.
Ensure stable, erosion-resistant surfaces that minimize erosion and
prevent loss of growth media (soil) form rehabilitated areas to surface
waters. (Goals 1 and 2)
Ensure management of soil and root-zone resources to maximize their
potential for use in rehabilitation. (Goals 1 and 3)
Minimise the area affected by mining and associated activities by
buffering adjacent undisturbed areas from any adjacent vegetation
clearance, therefore maximising their condition, contribution to
rehabilitaiton and ecological resilience. (Goals 2, 5 and 6)
Establish root zones and topography that support targeted native
ecosystems and ecosystem mosaics and support a high degree of
naturalness in the short and longer term. Naturalness means mined
landforms will not include permanent highwalls, pit lakes or extensive
linear features. (Goals 3, 5 and 6).
Establish self-sustaining, locally-characteristic native vegetation that
can naturally develop into a mosaic of native vegetation associations
resistant to fire, weeds and pests. (Goals 5, 6 and 7).
Conserve the genetic resources of plant species, (including
bryophytes), particularly those considered at-risk or threatened, both
within and outside the footprint. (Goal 6)
g.
h.
i.
To prevent weeds and pests invading the site so far as is reasonably
possible, and otherwise to identify and control weeds and pests on the
site so there is no negative influence on rehabilitation outcomes. (Goal
4)
Provide habitat that will develop in the longer term to be suitable for
roroa, lizards and other native fauna. (Goal 6).
Create at least 50 m2 [TBC] of tarns/ponds of varying size, shape and
hydrology with vegetation types which replicate the diversity of physical
characteristics and maximise the habitat values of the tarns/ponds to
replace the natural tarns/ponds that will be lost. (Goals 6 and 7).
This rehabilitation management plan details the strategies and procedures for all facilities
and operational areas to be adopted during the operation of the mine, and the postmining phase, in order to achieve a final rehabilitated landscape which is consistent with
these objectives.
In a sensitive environment such as Te Kuha, rehabilitation management will include
practically-orientated environmental induction, ongoing training and environment-related
KPIs for visitors, contractors and staff to minimise inadvertent damage to rehabilitated
and undisturbed areas. Te Kuha Limited Partnership recognises that communication
and understanding between mine engineers, geologists, earth works and environmental
staff is vital if environmental factors are to be comprehensively addressed in mining
operations at all levels.
2.3
Closure Criteria
Closure of the Te Kuha Mine will be achieved when the vegetation within each of the
major landforms identified has met or exceeded the closure standards identified in
condition X. These closure standards must have been achieved and maintained for at
least three years before the site can be closed. The rehabilitation assessment for
completion of closure of the site must be undertaken by a suitably experienced and
qualified plant ecologist.
2.4
Definition of Self-Sustaining
The aim of rehabilitation is for the vegetation to become:
a) Representative of secondary vegetation; and
b) Self-sustaining.
c) Contiguous with and connected to surrounding habitats.
Achieving self-sustaining vegetation is based on evidence of:
a) suitable root zone and quality (depth, stability, chemistry, hydrology, topography)
b) appropriate density of ‘foundation’ native plant species (which will vary according
to species and habitat type e.g. yellow-silver pine, beech, Dracophyllum densum)
c) absence of weed and pest pressures
d) appropriate variation at a landscape scale to underpin landscape mosaic
e) appropriate connectivity and absence of permanent features that prevent
connectivity
f) sustained development of native vegetation height and/or cover over a period of
at least five years so that natural succession pathways can develop under
passive management (without the need for input of extraordinary resources such
as fertiliser or intensive weed control or interplanting).
g) In addition, specific areas must provide habitat suitable for target fauna, and a
minimum area of direct transferred yellow-silver pine and herbfield is required
h) healthy buffer vegetation.
As rehabilitation progresses, monitoring and adaptive management will refine the types
of active intervention in rehabilitation areas and triggers for intervention.
2.5
Cross Reference to other Management Plans
The rehabilitation objectives link to other management plans prepared for the site
including:
•
Target species plans (bryophytes, forest ringlet butterfly, lizards).
•
Pest plant and animal (if a separate plan, currently added to this
plan)
•
Erosion and Sediment Control Plan
•
Boundary Effects Management Plan
•
Annual Work Plan
•
Mine Closure Plan
A Mine Closure Plan has been prepared (as set out in condition X) that sets out the
practices and procedures to be adopted to ensure mine planning and implementation is
undertaken such that closure of the site can be achieved in accordance with the
conditions of these consents, including the stated targets in condition X.
The Mine Closure Plan overlaps with this Rehabilitation Plan in a number of areas so
that rehabilitation will be completed in a timely fashion and closure can be achieved.
Sites that are rehabilitated in the first 3 years of mine operation should reach the closure
standards before the largest areas of rehabilitation are started.
…
Also show how rehab plan relates to the rehab ‘toolbox’
3.
MINE PLANNING MATTERS
3.1
Introduction
The timing and amount of soils1, wood and vegetation available for either storage or
direct transfer as well as the amount of engineered substrate available to be rehabilitated
via planting or direct transfer are all factors which need to be planned and managed to
optimise the overall rehabilitation outcome. Vegetation growth rates, climatic constraints,
slopes, aspects and local soil and overburden characteristics also have the potential to
affect rehabilitation positively or negatively so will be managed. Each of these factors
identified is discussed in more detail below.
3.2
Relevant Consent Conditions
In accordance with Condition X, no area is to be cleared of vegetation without being
either excavated, or revegetated in accordance with this plan, for a period of more than
12 months. The objective of this condition is to limit the early clearance of plants, increase
the area of direct transfer and maximise the potential of available vegetation.
Six monthly monitoring and reporting of the quantity and quality of topsoil stripped, stored
and available and the quality and quantity of non-acid forming (‘NAF’) material and
subsoils available and suitable for capping is required according to Condition X.
Condition X requires that XX ha of yellow-silver shrubland vegetation will be directly
transferred to suitable engineered surfaces.
3.3
Scheduling of Rehabilitation
Current scheduling indicates that no areas of the backfill that are to be revegetated will
be available for rehabilitation until Year 2.
The focus of rehabilitation in Year 1 will be the revegetation of road batters, conservation
of stockpiled rehabilitation materials, and enhancing the health of plants and ecosystems
in buffer zones. During Year 2, rehabilitation will be completed around the southern part
of the Main Lower Overburden Stockpile and to the south of the ROM area.
During Years 3 and 4 there is only limited additional space for rehabilitation, and much
of what is available for rehabilitation is “temporary” in nature (i.e. placed for up to 10
years before the material will be removed to its final location). Direct transfer will not
generally be used at temporary locations. Instead rehabilitation in temporary locations
will use of a high proportion of precocious woody species such as manuka, Olearia spp.,
Gaultheria spp., that may be useful seed sources, and species that can be used for
nursery plant propagation and relocation at the end of 10 years (e.g., flax, gahnia) [TBC].
A small area between the dam and the Lower Overburden Stockpile will be available for
permanent rehabilitation during Year 4.
From Year 5, when the southern part of the Paparoa Pit is backfilled and rehabilitation
begins there, the amount of permanent rehabilitation increases again, with both
1
Soils include suitable non-acid forming overburdens that can be suitable for use in soil profiles,
for erosion control as surface mulches.
permanent and temporary rehabilitation being undertaken in Years 5 – 8. Most of the
direct transfer area is expected during these years.
During Year 9, the first of the temporary rehabilitation in the Brunner Pit (laid down in
Year 4) will be removed and the underlying overburden used elsewhere. Only minimal
rehabilitation takes place in Years 9 – 11. The Brunner Pit would be completed in Year
11 and rehabilitation of the Paparoa Pit continues throughout Years 12 – 14, with
rehabilitation commencing on the northernmost strip of the Brunner Pit in Year 13.
From Year 16 the focus shifts to filling the final void in the Paparoa Pit and creating the
new, lower ridgeline. The Run Of Mine (“ROM”) area would be rehabilitated in Year 16,
when the bulk of the temporary rehabilitation in the former Brunner Pit is removed and
rehandled into the final void. Rehabilitation increases in Years 17 and 18 when the new
ridgeline is completed and areas of final rehabilitation extend downslope replacing the
last of the temporarily rehabilitated areas, reshaping the dam area and removing the last
of the Overburden Stockpile sites.
3.4
Direct Transfer
As outlined in Section 3.2, direct transfer of XX ha of yellow-silver pine shrubland will be
required to comply with the conditions of consent. Direct transfer from the source site
direct to the final destination (i.e without intermediate storage) is only able to be used in
Years 2 and 5 – 8 as appropriate reconstructed landforms become available at the same
time there is shrubland and other habitats available for direct transfer. However, direct
transfer will also be used to rehabilitate haul road fill batters and bunds around
infrastructure and storage areas in years 0 and 1.
3.5
Soil Management
3.5.1
Soil auditing
Conservation and reuse of topsoil underpins rehabilitation success at most West Coast
mine sites because the native, herbaceous nitrogen fixers in the area are restricted to
tutu (Coriaria spp.), which is palatable. There are few other options to accelerate plant
growth on nitrogen-deficient substrates such as rock overburden, other than by
spreading organic material in the form of topsoil.
Anticipated soil yields, scheduling and storage requirements are described in the Palaris
(2016) report. These volumes will be reconciled with the actual volumes as mining
progresses in order to allow adaptive management of the soil resource to optimise quality
and volume for rehabilitation purposes.
3.5.2.
Soil Volume
The volume of soils stripped, soils stored and soils used as well as the quality of those
soils for rehabilitation purposes will be recorded and verified at regular intervals and
matched to anticipated soil demands.
In the event that soil volumes are insufficient for rehabilitation, amendment of suitable
non-acidic overburdens with organic materials may be possible depending on the nature
of the overburden and organic materials available.
Table 1 shows the indicative stripping and replacement of topsoil during the stages of
mining described below (based on the existing schedule). This will be updated once the
final schedule is developed closer to the commencement of mining. All the stockpiled
topsoil will be used to rehabilitate Te Kuha Mine and associated disturbed areas as
shown in Table 1.
Table 1: Indicative topsoil stockpile management.
Topsoil Stripped (m3)
Topsoil
Topsoil
Year
Stripped
Stockpiled
Mine Opening
1
142,530
142,530
2
14,400
129,300
Sequential Rehabilitation
3
21,390
148,440
4
9,240
146,010
5
18,960
147,840
6
6,330
145,890
7
19,320
151,860
8
4,650
138,420
9
5,430
137,340
10
13,710
137,730
11
1,950
137,280
12
0
124,770
13
0
122,400
14
0
108,450
15
0
108,450
Mining
Ceases
16
0
109,860
17
0
107,820
18
0
76,350
19
0
0
Total
257,910
3.5.3
Topsoil Used (m3)
0
27,630
2,250
11,670
17,130
8,280
13,530
17,910
6,510
13,320
2,400
12,510
2,370
13,950
0
1,410
2,040
31,470
76,350
Soil Quality
Along with soil quantity and scheduling of overburden availability, the quality of
overburden and soils underpins rehabilitation. The local plants are naturally adapted to
low available nitrogen and phosphorus, imperfect to poor drainage, and naturally acidic
substrates. Soils overlying Brunner Coal Measures are typically highly acidic (pH 4 to
4.9) and can have acid-generating subsoils. However, the presence of Paparoa Coal
Measures at Te Kuha allows NAF Paparoa substrates to be preferentially used for
capping PAF Brunner materials, thereby avoiding growth-limiting pH in root zone.
Nonetheless overburden pH will be monitored and managed to avoid excess acidity in
the root zone for rehandled overburden rock and soils.
In addition to pH, other aspects of soil quality which are important to rehabilitation
success include preservation of organic matter (the source of nitrogen and holder of
water) and rooting depth. Rooting depth is affected by degree of compaction, slope and
extent of soil saturation. The value of soils is enhanced if vegetation and soil life (such
as worms and fungi/mycorrhizae) are present; the rapid establishment of new plant cover
in both stockpiled and respread soils helps maintain these organisms..
One goal of the rehabilitation is to maximise immediate reuse of materials and avoid
stockpiling because stockpiling lowers soils quality; the soils are structurally damaged by
double handling and lower parts of soil stockpiles may become anaerobic. Hence
advance stripping (more than 12 months prior) reduces potential for effective
rehabilitation. In the event that soil quality is lower than required to support growth rates
adequate to achieve closure, remediation options available include changing the planted
species, increasing planting density, or changing pre-planting practices to include
physical remediation, addition of wood, other organic matter and/or fertilisersto
responsive species or in affected areas.
3.5.4
Soil Usage
The engineered landform will be constructed in short (< 5 m high) lifts and include a
minimum 2 m thick cap of NAF material with the underlying material having an expected
permeability of 10-6 m/sec. As part of soil monitoring the volume of soil used will be
reconciled against existing stockpiles and predicted future demand.
3.6
Vegetation Growth Rates and Colonisation
Te Kuha climate is characterised by minor, short-term, moisture deficits. However, plants
with small, shallow roots (e.g. recently planted or germinated) and those on free draining
substrates, such as gravelly mine overburden, can be exposed to moisture stress in
summer. Te Kuha is also exposed to westerly weather and this could be expected to
reduce growth rates at some locations, particularly exposed, higher-altitude sites.
Plants in the Te Kuha area are expected to typically grow at slow to moderate growth
rates, depending on the plant species, altitude, and the level of exposure. Growth is
expected to be slowest at higher, more exposed sites, on sites with shallower rooting
depths. Growth rates of typical nursery-grown species are likely to be in the order of 40
to 80 mm height and breadth /year (at least initially) [TBC].
Both slowly dispersing and rapidly colonising species are to be established at Te Kuha.
The narrow shape of the pit, 400 to 600 m wide, retention of vegetation around and below
the site and replacement of soil substrates with low to nil competition from weeds will
assist natural colonisation. The use of hand salvaged and nursery grown plants, some
of which will be precocious seeders (i.e. rapid colonisers), will also assist with natural
dispersal and colonisation at the site. However, some key plant species, such as beech,
mountain flax and podocarps, are slow to disperse and/or, seed irregularly (in ‘mast’
years). Others, such as ferns, manuka, olearia spp., hebes, southern rata (Metrosideros
umbellata), cutty-grass (Gahnia species), mountain daisies (Celmisia spp.) and
snowberry (Gaultheria spp.) are better colonists of bare areas and can be expected to
increase in frequency and percentage cover relatively quickly.
3.7
Climatic Influences
The key climatic factors limiting growth are probably low solar radiation due to the
frequent cloud and mist cover and cool temperatures – although frosts are uncommon,
occurring on 5 to 10 days per year (snow falls are rare). Between 2010 and 2016 there
were, on average, 9 rain-free days (ranging from 3 to 16 days) per month at Te Kuha
compared with 13 rain free days per month in Westport. On elevated areas, particularly
the newly created ridgeline, vegetation height will also likely be suppressed by high winds
that ‘shear’ the vegetation, leading to prostrate growth forms dominating, e.g., manuka,
Dracophyllum sp. Sheltered microsites will be created by using coarse wood (logs),
boulders and uneven hummocky topography.
Te Kuha experiences high, evenly distributed, and periodically intense rainfall. Data from
2012 – 2017 indicates maximum daily rainfall /month is lower than at Stockton but higher
than Westport (mean 110 mm/day at Te Kuha compared with 180 mm/day at Stockton
and 40 mm/day in Westport). Annual rainfall at Te Kuha during the same period was
between 4.8 and 5.8 m. These frequent, high-intensity rainfalls can quickly erode
unstable or unprotected substrates. Methods to reduce erosion are discussed in Section
X of the Erosion and Sediment Control Plan.
3.8
Slope and Aspect
Removal of vegetation for direct transfer will only be constrained by slope in relatively
small areas within the footprint. Figures 14 and 16 of Mitchell Partnerships (2013) detail
the slope constraints and the high value ecosystems with a potential for recovery as
direct transfer respectively.
After completion of mining, maximum batter slopes, angles and bench widths are
dictated by geological conditions. The requirement to blend constructed landforms into
adjacent landforms and landscapes will also influence the slopes achieved. Minimum
slope angles are dictated by ecological requirements, since low slope angles help create
impeded drainage conditions which helps drive dominance of some plant associations,
including tarns and herbfields. The fine-scale changes in batter slope, aspect and
drainage will be key to creating a coarse mosaic of ecosystems over the medium to long
term.
The performance of any modified landform will be such that under a Probable Maximum
Flood or Maximum Credible Earthquake no damage to landforms will result greater than
those that would have occurred under natural slope and landform conditions.
3.9
Knowledge Gaps
Rhytida Snails
Bryophytes (currently have separate plan)
Propagation of M parkinsonii
Lizard densities (currently have separate plan)
Forest Ringlet Butterfly (currently have separate plan)
Proposal is to manage these adaptively.
4.
REHABILITATION DESIGN
4.1
Introduction
The overall design of the rehabilitated landscape (condition X) will provide:

Habitat linkages, for example, for great spotted kiwi, lizards.

The construction and vegetation of new stream channels.

The direct transfer of at least X ha of shrubland communities, at this stage
without intermediate storage.

Varied topography, across the backfill to create a sympathetic landscape that
blends into adjacent landform without highwalls, and avoids an engineered
appearance.

The reinstatement of terrestrial bryophyte habitat via direct transfer of
shrubland and boulders.

The reinstatement of rock piles and boulders surrounded by dense, low
growing vegetation as habitats for lizards.

Rehabilitation procedures that will maximise the blending of the rehabilitated
haul road within the adjacent landscapes and minimize the visual impact of
the reduction in height of the new ridgeline.

Tarns.
Each of these is described in more detail below.
4.2
Habitat Linkages, Varied Topography and Blending In
There are four main types of vegetation at Te Kuha forest, coal measures shrubland,
herbfield and rockland (described briefly in Section 1.2 and in more detail in Mitchell
Partnerships 2013). Specific rehabilitation aims have been developed for each of the
ecosystems to be rehabilitated, both individually, and considering their fit within the
surrounding natural landscape.
Figure 1 [to come] shows the different areas, and how they relate to one another. The
majority of the rehabilitated area would be forest/shrubland established on backfilled
overburden on slopes less than 20°.
The overall design of rehabilitated landscapes aims to maximise integration with the
adjacent natural landscapes. Avoiding straight linear and regular features where
possible and mimicking natural landform slopes will help achieve this.
The overburden landform will abut the surrounding natural topography and this will
enhance ‘naturalness’, enhance connectivity and accommodate access. Combined with
‘islands’ of direct transfer vegetation across the site, including as buffers for sensitive
habitats, this approach will maximise connectivity and flows of seeds and spores across
the site ensuring ecological connection is established.
Integration is also achieved by establishing vegetation on rehabilitated landforms that is
similar to adjacent undisturbed vegetation.
Figure 1: Rehabilitation concept for Te Kuha Mine [to come]
4.3
Direct Transfer of high priority ecosystems
A minimum of 700 m2 of herbfield [TBC] will be established on the reconstructed slopes
of Te Kuha along with at least X ha of yellow-silver pine – manuka shrubland. Scheduling
of the transfer of this vegetation awaits the final mine schedule. Based on the existing
schedules the following applies:

Salvage of forest communities will commence when the Year 1 mining activities
commence and the potential exists for creating directly transferred shrubland
vegetation (with no intermediate site) in Years 2 and 4 – 10 because a final
landform is expected to be ready to receive the transfer and undisturbed
vegetation is able to be salvaged.

After Year 10 the rehabilitation will rely mostly on planting and seeding, with some
salvage of plants from stockpiles, because of the lack of intact vegetation
remaining to be stripped.
5.
PREFERRED REHABILITATION SPECIES AND
METHODS
5.1
Rehabilitation Process
Condition X requires the identification of preferred species and rehabilitation methods for
the various areas of the mine site, including wetland environments and banks of stream
channels. Condition X specifies that all planting stock for the mine site itself is to be
sourced from the Te Kuha area or within the Ngakawau Ecological District above 500 m
asl. A base list of species to be propagated for rehabilitation is provided in Section 5.2
and a list of species proposed for use at Te Kuha is provided in Appendix 2.
Conceptually the rehabilitation process consists of six steps:
1.
Identifying and prioritising existing material for use in rehabilitation prior to
stripping.
2.
Stripping and salvage of suitable materials prior to mining.
3.
Immediate use of living soil and plant material (prioritised) or stockpiling of
material awaiting formation of the engineered landform suitable for its return.
4.
Construction of designed landform
5.
Return of material to create suitable root zone and micro-topography; and
supplementation with seed, nursery seedlings, transplants and other
vegetation as required. Reconnection with landscape processes.
6.
Maintenance and adaptive management.
Each of these steps is dealt with in more detail below, followed by a methodology for
each of the four main vegetation associations (forest, shrubland, herbfields and tarns
and banks of streams). Note that the protection and enhancement of residual
ecosystems in buffers is a separate activity, done in advance of vegetation stripping, as
is the identification and relocation of specific fauna (under wildlife permits) if required.
From the overall and specific rehabilitation aims, methods and closure standards,
rehabilitation procedures have been developed for each of the constructed landforms
identified. The proposed activities are based on the current schedule and may change
in future versions of this plan. A variety of methods will be used including direct transfer
(either mechanically or by hand), seeding and fascining, planting of nursery seedlings
and hydroseeding. More detail on each of these methods is also provided below.
5.2
Identifying Material for Use in Rehabilitation
The following steps will be taken to identify and prioritise soil, vegetation, rock and rubble
resources before any drilling, haul road development or overburden stripping begins:

To minimise the mine footprint, the boundary of the block or area to be
disturbed, covered or stripped will be defined by marking it physically on the
ground and plotting GPS coordinates on the topography map.

If the area is adjacent to any undisturbed land (outside the planned mine
footprint), identify any particularly sensitive or significant species along the
boundary and assess potential for avoidance or mitigation of impact. The
protection of such boundaries is addressed in the Boundary Effects
Management Plan or Annual Work Plan?.

Identify salvageable rehabilitation resources and probable volumes in the area
to be disturbed. This includes any high value habitats and any known habitats
for target fauna. Other potential resources include plants/seed (propagation
materials), topsoil, subsoil, favourable quaternary materials, logs, weathered
boulders and any bryophyte-covered boulders – particularly those in full light
than have potential for successful relocation. The potential for capture and
relocation of fauna species such as lizards and roroa also needs to be
scheduled as provided for in the relevant management plan. In the areas near
the ephemeral pond and former hut site, identify any weed species present
and quarantine the soils and vegetation to a specific storage area where crosscontamination can be minimised,

Identify potential destinations for stripped material. Confirm destinations have
adequate surface area, slope, access, water control and surfacing. Identify
contingency areas in the case of unfavourable weather or other delays. The
destination of any fauna to be relocated will also be identified as specified in
the relevant management plan.

Identify and prioritise the methods of pre-treatment and salvage, and the time
required to salvage each area and/or rehabilitation resource in consultation
with the mine engineer.

Machinery operators must develop protocols to ensure the direct transfer and
jumble dump specifications in this plan can be met.
The rehabilitation supervisor is required to sign off the Te Kuha haul road construction
plan, each stripping block plan, overburden placement area level and stockpiling area
before access roads are constructed. Any access road required as part of the drilling
programme or water management programme will also require signoff by the
rehabilitation supervisor before construction. This is to ensure rehabilitation resources
are salvaged from the entire footprint, including drill access roads, and that short-term or
temporary roads do not adversely impact future rehabilitation potential.
5.3
Rehabilitation Scheduling
Progressive rehabilitation requires rehabilitation activities to be integrated into routine
(daily, weekly, or monthly) mining operations. On-site and on-the-ground management
dedicated to rehabilitation will ensure optimum scheduling (critical to ensure maximum
lead times for stripping vegetation and soils), optimum timing of seed and seedling
collection (both seasonally and annually), and ensure accurate records are kept of
rehabilitated areas. A dedicated rehabilitation and stripping workforce enables staff to
become expert at identifying soil and vegetation boundaries, and progressively amend
techniques to obtain consistent results under variable conditions.
Rehabilitation can be divided into three stages which correspond to the main phases of
mine development: mine opening, sequential rehabilitation, and mine closure. Table 2
shows an indicative sequence of rehabilitation based on the areas available at different
stages of mine life. This can be amended to reflect changes in the detail of mine
scheduling as mining progresses. Mine opening begins with development of the access
road and excavation of the initial 16 hectare cut in the Brunner Pit and construction of
the 19 ha overburden area and 10 ha stockpile area. Mine opening ends when areas of
the final landform are available for rehabilitation in Year 2. During the mine opening
phase soils and vegetation are salvaged and placed in the stockpile area. Rehabilitation
is restricted to batters along the haul road and around part of the soil stockpiles and
infrastructure area.
Table 2: Indicative areas disturbed (cumulative) and rehabilitated (increments)
each year excluding loadout facility area.
Area Disturbed (ha)
Road
Overburden
Year
Area
Area
Mine Opening
1
?
28.9
2
?
25.1
Sequential Rehabilitation
3
22.8
4
26.4
5
18.5
6
22.5
7
25.4
8
24.3
9
24.7
10
22.6
11
23.3
12
22.3
13
25.1
14
23.6
Pit
Areas
Road
Area
16.2
17.4
?
26.1
23.8
29.7
26.4
25.3
22.1
21.0
28.1
22.3
18.6
15.4
12.3
Area Rehabilitated (ha)
“Temporary” Permanent
Area
Areas
-
9.2
2.0
1.4
1.2
2.0
5.1
2.2
0.8
0.8
0
0
1.3
0.8
1.9
4.3
1.6
2.6
0.9
0
3.6
0
4.2
0.8
3.3
Area Disturbed (ha)
Road
Overburden
Pit
Year
Area
Area
Areas
15
24.4
11.4
Mine Closure
16
8.3
0
17
8.3
0
18
4.9
0
19
0
0
Total
Note:
Area Rehabilitated (ha)
Road
“Temporary” Permanent
Area
Area
Areas
0
0
(8.6)
(3.6)
(4.7)
0
16.8
16.7
7.8
19.9
25.5
102.9*
Numbers in brackets are temporarily rehabilitated areas that are removed.
*This total includes replacement of 16.8 ha of temporary rehabilitation with permanently
rehabilitated surfaces.
The second mining stage, sequential rehabilitation, focuses on rehabilitating sections of
the overburden landform and former pit that are backfilled to final contour. The aim of
scheduling during this second stage is to move stripped soils and vegetation (primarily
as direct transfer if practicable) directly from stripped areas to rehabilitation areas,
therefore avoiding double handling, and maximising regeneration of shifted materials.
Since direct transfer is not practicable during all years of mine life, planting of nursery
raised seedlings and potentially seeding/brush layering (fascining) will also form a
significant component of the sequential rehabilitation. Since construction of temporary
overburden stockpile areas with a life of 4 – 10 years is anticipated, these areas will
require vegetative cover to retain sediments and protect the soils and other resources
during their life. This temporary rehabilitation will make use of locally sourced, fast
growing and generally precocious species.
The third stage of mining focuses on mine closure and the rehabilitation of the final
landforms using stockpiled material, nursery plants and seeding. Throughout all stages
the previously rehabilitated areas will be maintained, and pest and weed control
programmes will be operative.
Mine Opening
Mine opening begins with the development of the approximately 9 km long access road
from Nine Mile Road to the Te Kuha site, in conjunction with the stripping of soils and
vegetation from the initial 16 ha cut in the Brunner Pit. During this stage of mining
salvage of vegetation will be undertaken where possible for use in rehabilitating the road
batters.
During this time manuka will be harvested for fascining and seed sowing and suitable
plants will be salvaged by hand for planting on completed batters (intensive transfer).
Some overburden will be used as fill in road construction. The multiple lift method of
construction will be used to construct the overburden stockpile landforms, as this allows
the outer edge of each lift to be rehabilitated as soon as it is completed, decreasing the
volume of vegetation and soil that needs to be stockpiled.
By the end of Year 1 approximately X ha of road fill batters will be rehabilitated using
direct transfer, intensive transfer and fascining with seed-bearing branches of manuka.
Suitable wilding plants will be salvaged from cleared areas as available. Fill batters on
the south-western side of the ROM area will be revegetated using the same techniques
during Year 2. Batters around the soil stockpiles and sediment ponds will be generally
revegetated using intensive transfer of individual wilding plants directly into overburden,
as this best allows reuse of the plants in other rehabilitated areas if these structures are
removed at mine closure.
Some topsoil will likely be stored for at least 10 years, as more topsoil will be stripped in
the first two years (from up to 33 ha) than is required for rehabilitation during the first half
of mine life. These soils will be used to rehabilitate the 25 ha of final landform created
at the end of mine life (Year 19).
Sequential Rehabilitation
Once final surfaces are available for rehabilitation, stripped mixed vegetation and soils
will be trucked directly to areas needing rehabilitation where it is practicable to do so,
and rehabilitation will be a continual process, subject to weather and mine planning
constraints. Any residual stripped vegetation and soils will be stockpiled. Direct transfer
will be undertaken wherever practical as the priority rehabilitation technique. It is likely
a range of direct transfer machinery may be developed and deployed.
Mine Closure
The third stage of rehabilitation focuses on the rehabilitation of the northern end of the
Paparoa pit, and the ELFs at both the northern and southern stockpile areas once the
stored topsoil and other rehabilitation materials have been used in rehabilitation. Topsoil
will come from stockpiles, favourable non-acid-forming lower root zone from favourable
areas of reworked backfill, and all seedlings will be nursery-raised or sourced from onsite ‘nurseries’ created by direct transfer, and salvage of wildlings regenerated from
areas of jumble-dumped, stockpiled soils during the storage period.
5.4
Stripping and Salvage
The main components and methods of stripping, in the order they are applied to any
disturbed area (e.g.haul road, each stripping block) are the following:

Plan stripping methods, access matched to machinery required and timeframe with mine engineer.

Work around the edges of herbfields and bare areas.

Pre-stripping survey of prioritised plants (including bryophytes and weeds),
ecosystems and collection of any target fauna as per the relevant Wildlife
Permit. Ensure areas with weeds are placed in ‘quarantine’ stockpiles

Pre-treatment - felling of trees over 3 to 4 m tall into lengths able to be safely
handled with available machinery.

Intensive hand direct transfer of vegetation if necessary.
The following four actions may happen at the same time or separately, depending on the
machinery used. An excavator may have several quick-release attachments allowing
one machine to manage direct transfer of vegetation (flat-based, square edged bucket),
handling boulders/general mixed soil (toothed bucket), or wood (Grapple) or separate
machines may be used.

Machine direct transfer of vegetation with complete underlying root mass (up
to 700 mm depth for taller plants). Sods with very short plants should be
placed close together to avoid bare soil between sods to minimise the risk of
desiccation and weed invasion. Taller plants, and particularly tree root plates,
can be spaced to cover a greater area as long as loose soils are placed
between the sods to prevent edges being ‘proud’ and drying out.

Coarse wood extraction (forest logs) and placement on rehabilitated areas
prior to revegetation at a density that assists erosion control and plant growth,
or transfer to storage area. Logs can be stored as a final protective layer on
soil stockpiles.

Boulder extraction (especially weathered boulders or bryophyte-covered
boulders, mark North aspect on bryophyte boulders to align in rehabilitation
areas) and transfer to storage area.

Machine transfer of residual disturbed vegetation with topsoil and favourable
subsoils to storage area or rehabilitation areas for use as a root zone or for
buffering sods of direct transfer (if material is relatively friable).

Stripping of low quality subsoils.

Conventional stripping of overburden, with non-acid forming overburdens
suitable for lower root zone (i.e. surrogate subsoils) and/or nominal 2 m deep
cap identified and adequate volumes stockpiled for rehabilitation.
High-quality stripping uses face shovels, backhoes or other purpose-built machinery to
accurately remove direct transfer sods with a flat base which includes the full depth of
the root system (i.e. topsoils and upper subsoils) where possible. Each sod is handled
only once before loading into trucks for transport to stockpiles or, preferably, directly to
rehabilitation areas.
Where stripping is not direct transfer, high quality stripping removes only the topsoil and
vegetation and smaller rocks, avoiding mixing in subsoils and again, with minimal
handling to retain structure and aeration during storage.
The priority methods for vegetation salvage are intensive hand and machine direct
transfer to areas requiring rehabilitation, and to the on–site propagation nursery. The
requirements at the source site are:
Hand direct transfer
Access for light vehicle with trailer for hand salvage of
plants. Depending on the vehicles used, this may mean
a maximum slope of 1:5, road width 2 to 3 m, <200 mm
road surface variation, and road density of 50 to 100 m
for cost-effective hand salvage.
Machine direct transfer
Access suitable for stripping and transport vehicles,
including potential passing bays /wait areas.
At the same time revegetation methods and access to prepared revegetation sites site
need to be planned with the mine engineer:
Prepared rehabilitation site NAF cap established (if applicable), site edges contoured
to complement adjacent ground, suitable final contours
established to meet natural topographic objectives, storm
water controls in place, surface meets permeability
criteria for vegetation being established (e.g. low
permeability for herbfield and some shrubland
communities)
Machine direct transfer
Availability of suitable machinery at direct transfer
receiving area to prepare ground, manage sods,
potentially unload sods and place soils/subsoils around
sods as necessary as sods are unloaded.
Hand direct transfer
Access for transporting vehicles to areas being
rehabilitated at a density of 50 to 100 m for planted areas
throughout the duration of expected planting period.
Temporary erosion control
Areas that are revegetated without using direct transfer
may require surface treatments to minimise erosion of
soil and sediment. Methods applied will depend on an
assessment of erosion risk – refer to the Erosion and
Sediment Control Plan.
5.5
Stockpiling
The priorities for stockpiling rehabilitation resources are: boulders with
bryophytes/lichens, topsoil with mixed vegetation, coarse wood, favourable subsoils and
weathered boulders. Stockpiles will be separated into the following classes:






Mixed topsoil and vegetation for reuse.
Mixed topsoil and vegetation from weedy areas that needs to be quarantined
from water courses and specially treated.
Coarse woody debris (tree trunks and stumps), noting that a layer of coarse
woody debris across soil stockpiles can be useful and acceptable.
Weathered boulders.
Topsoils.
Favourable subsoils and overburdens, such Paparoa Coal Measures. [TBC?].
Other resources, for example, rock mulches for surfacing, or boulders for lining water
courses, may be salvaged or produced as required as part of mining activities.
The majority of soil and vegetation will be stripped with coarse woody debris, smaller
weathered rocks and about 20 to 50 cm of underlying topsoil and favourable upper
subsoils (favourable subsoils contain roots and may be white or grey). The stripping
depth will not generally exceed 50 cm unless there are abundant roots below this depth
such as occurs in some well-drained Brown Soils under tall forest. The inclusion of rocks,
plants and wood helps maintain living, aerated stockpiles, and produce a rough, erosion
resistant surface when spread on rehabilitation areas as well as reducing over-working.
Three stockpile areas are planned, two to the north of the Brunner Pit and the main lower
ELF area with a third to the south of the Paparoa Pit, east of the main lower ELF.
Changes to the scheduling and destination of non-or low-acid forming material (“NAF”)
mean that NAF material will be used in rehabilitation at Te Kuha and any potentially acid
forming (“PAF”) material will be buried at depth to secure it and prevent acid mine
drainage. The specific details of soil storage and storage of other materials will be
developed during detailed mine planning.
Clean runoff will be diverted around bermed and rip-rap lined stockpile areas. Runoff
from within the bermed areas will be captured and settled in one of several small
temporary dams or one larger life-of-mine dam located north of the ROM area before
being discharged to the clean water diversion system or local tributaries.
Stockpiling Mixed Topsoil and Vegetation
Stockpiles of mixed topsoil and vegetation will be created by back-dumping truckloads
onto a levelled stockpile surface, creating a ‘herringbone’ pattern. Stockpiles may range
from 2 m to 4 m height depending on the size of trucks. The mixed soil and vegetation
will not be smoothed or trafficked by machinery. The rough surface helps trap sediment
within the stockpile. Minimal handling during stripping helps retain permeability, soil
structure and regeneration potential of the vegetation.
If stockpiles have low vegetative, wood and rock cover at the surface on deposition, the
erosion potential can be reduced by applying a coarse wood cover of salvaged logs or
fascining with shrubs and small trees. If a non-native grass seed or straw mulch is used
to create cover, the treated areas will be subject to additional monitoring and
maintenance to prevent non-native species flowering or seeding. The preferred nonnative species is annual rye-grass (which is likely to be short-lived in the conditions at Te
Kuha as it is at Stockton, meaning it is less likely than other grass species such as
Yorkshire fog, fescue, sweet vernal or brown-top to set seed and become a nuisance
weed species).
Design of the Direct Transfer Storage Area (if required)
Ecosystems that are to be direct transferred under condition X may need to be stored at
an intermediate location before placement in permanent rehabilitation areas [TBC]. This
will require an area of approximately X ha, including accessways. A gently sloping
landform with an even, compacted surface will be constructed and covered with an even
depth (nominally 100 mm) of suitable substrate. The compacted base and even layer of
substrate will reduce root damage when removing the sods later.
Sediment control and defined foot access for monitoring will be developed as the area is
constructed.
Stockpiling Woody Debris and Weathered Boulders
Woody debris and, if necessary, weathered boulders will be stored in locations that allow
their use as required on rehabilitated surfaces. Storage of this material is expected to
be within the proposed stockpile footprint, and pit backfill prior to rehabilitation,
depending on final sequencing.
Stockpiling Topsoil
Topsoil will be stored for up to 18 years, as topsoil stripped in the first two years (from
up to 33 ha) will be used to rehabilitate the final landform created during the second part
of mine life (after Year 10). Experience elsewhere with tussock, shrubland and low forest
stripping indicates there is likely to be substantial regeneration of plants in the stockpiles
within five years. Provided the stockpiles are kept weed free, some of these plants may
be salvaged as intensive hand transfer, and potentially as direct transfer sods, before
the underlying topsoil is excavated for placement on rehabilitation areas.
The 10 ha stockpile areas are designed to store 201,000 m3 of topsoil (at mean 2.5 to 3
m depth), allowing t 200 mm depth of topsoil to be placed over rehabilitated surfaces on
average. If more than 201,000 m3 topsoil needs to be stored, e.g., because larger areas
are stripped or there is a delay in completion of final landforms available for rehabilitation,
one or more of the following strategies can be adopted:

Increase storage in the stockpile area by increasing mean height.

Create short-term stockpiles within the pit or overburden landform footprints.

Increase depth of soil in rehabilitated areas with low erosion potential where
taller forest is an acceptable rehabilitation outcome.
If the latter option is adopted, 10 ha of stockpile can still achieve a minimum 100 mm
depth of topsoil over the surfaces to be rehabilitated at Te Kuha.[TBC]
5.6
Direct Transfer and Revegetation
5.6.1
Direct Transfer
Condition X requires the direct transfer of at least X hectares of high value ecosystems
and X m2 of herbfield to rehabilitated landforms.
The direct transfer of herbfield may require construction of the intermediate storage site
as above prior to commencement of the excavation.
5.6.2
Revegetation Methods
Methods to be used for revegetation include:







Hand direct transfer (intensive transfer).
Machine direct transfer.
Natural regeneration
Planting of nursery seedlings.
Seeding and fascining.
Fertiliser application.
Hydroseeding.
The main revegetation methods are direct transfer, natural regeneration, planting of
seedlings and seeding are interchangeable, since they are all designed to achieve
closure plant cover in the medium term. However, plant diversity and growth rates vary
between each method and therefore a hierarchy of methods will be adopted.
Direct transfer is to be used wherever possible because it achieves by far the highest
diversity and presents the lowest risk of any technique. Direct transfer habitats typically
have high resilience to erosion and this method is the only technique that is able to
consistently establish large bodied invertebrates, including worms. Planting and seeding
in will be used in conjunction to supplement natural regeneration from rehabilitated top
soils mixed with vegetation.
A combination of all techniques will be used on road batters and rehabilitated pit areas,
however direct transfer will be the main technique for road fill batters to achieve high
erosion resilience and limit impacts on adjacent (undisturbed) vegetation. The minestripping schedule limits significant use of machine direct transfer as described in Section
5.3 above. Furthermore each technique has particular advantages:

Direct transfer provides the best outcome and most rapid recovery.

Hand direct transfer of salvaged wildings at wide spacing (2 to 5 m) is useful
to visually mark rehabilitation areas prepared for planting (for example flax)
and introduce species that will self-propagate, such as Celmisia and wire-rush
(Empodisma minus).

Machine direct transfer is suited to revegetation of slopes up to about 18
degrees and steeper slopes within the reach of the unloading digger.

Natural regeneration is low cost and can exponentially increase the canopy
cover of locally adapted species provided that weed suppression is effective.

Nursery-raised seedlings are an effective way to establish a range of common,
faster-growing species and ensure minimum density of some poorlydispersing species such as beech.

Seeding increases plant numbers, cover, and potentially diversity (particularly
of bryophytes and herbs) in the medium term.
Each of the revegetation methods is considered in more detail below.
Hand Direct Transfer (Intensive Transfer)
This technique will be used to transfer herbfield materials if they are found to be
unsuitable for machine direct transfer. For suitably sized species in suitable soils, hand
direct transfer can also be useful to establish areas for efficient collection of seeds and
propagules, It can also be used to target resilient plants (such as flax) for visual
demarcation of planted or seeded areas close to road edges.
The minimum preferred sod size is 150 by 150 mm, with the full rooting depth of each
plant targeted in the sod. Larger sods are preferred, as these are associated with a
greater diversity of ‘hitchhiking’ plants, and less disturbance of the target plant’s root
system which leads to higher survival. There is a practical trade-off between size, health
and safety, and efficiency of salvage because large sods are heavy. Sods are packed
firmly together, edge to edge and plant to plant, during transportation, and are planted
so that the rehabilitated soil is level with or slightly higher than the surface of the sod (to
avoid burial of hitchhiking plants but also avoid edges of the sod being proud if
rehabilitated soil settles). The soil around each sod is firmed in and soil wash from uphill
can be mitigated by locating rocks immediately above the transplant area. The best times
of year to salvage plants are spring through early summer, and autumn. Plants tend to
transfer most successfully when not in flower.
Machine Direct Transfer
Direct transfer is the precise excavation of 2 – 4.5 m2 “clumps” or “sods” of plants or
stumps with so 10 – 50 cm deep sod which includes most or all of the plant root system.
Sods are carefully placed in a single layer and transferred onto either areas prepared for
rehabilitation or onto storage areas.
Residual plants, topsoils and suitable (friable, non-acid generating) underlying subsoils
are salvaged in separate loads. These materials can be placed to assist in stabilising
taller direct transfer sods, reducing moisture loss from the edges of sods, and creating
smoother ground.
.
Planting of Nursery Seedlings and Salvaged Wildings
Nursery-raised plants will be propagated from seed, cuttings and divisions. Salvaged
plants used to generate material for nursery-propagation will occupy approximately one
hectare of the first area rehabilitated in years 2 and 3. Any other plant material used for
nursery production will be preferentially sourced from the Te Kuha area, or from the wider
Ngakawau Ecological District above 500 m asl (required by consent condition X).
Planting will carried out using at least ten native species to create an irregular pattern
and relatively natural appearance, while achieving a defined plant density. Planting
density will vary depending on the extent of natural regeneration and site-specific factors,
including the final community required, expected growth rate, the quantity of wood and
boulders on the rehabilitation surfaces and time to closure.
Planting density is likely to be increased in rehabilitated areas that are vulnerable to
erosion or weed pressure, where fast cover is desirable, and lower where growth rates
are high, sites are stable, and natural regeneration is vigorous.
Fertiliser Application
Fertiliser enhances growth of some plant species such as flaxes and hebes growing in
soils at Stockton (Theinhardt 2003). Fertiliser is not essential. It does not mitigate
against the effects of exposed conditions, and may exacerbate vulnerability of some
species Grasses (particularly exotic pasture grasses and toetoe) and rushes generally
show a strong positive response to fertiliser. No fertiliser will be broadcast where risk of
weed establishment is moderate to high, however inorganic nitrogen and phosphate
fertilisers may be used in suitable areas. Also, fertiliser will be included in most
hydroseeding mixes used on cut batters and highwalls, as trials at Stockton indicated
moss cover is maximised when fertilisers are included.
Seeding and Fascining
Fascining, hydroseeding and broadcast seeding may be used at Te Kuha to establish
vegetation, particularly in areas where planting and direct transfer is not feasible for
safety reasons or where areas are inaccessible.
Fascining involves placing branches of suitable species that hold ripe seeds over the
ground to achieve a 30 to 60% cover. In exposed areas, branches can be fixed to the
surface with pegs and wire, biodegradable netting or weighted down with rocks. The
branches provide a protective microenvironment for germination and developing
seedlings, and help to control soil erosion by protecting the soil surface from raindrop
impact and increasing surface roughness. Manuka is generally the most widely used
species as it is the preferred nurse crop for forest and shrubland. Seed-bearing branches
of manuka and other suitable plants may be harvested from within the mine footprint for
this purpose, including from older rehabilitated areas.
Hydroseeding
Hydroseeding is the application of a water-based slurry of seeds and plant fragments,
adhesive, a mulch of wood or paper fibre and fertiliser, using high-pressure hoses. It is
important to start with as rough a surface as possible, as hydroseeding mulch adheres
better to rough surfaces, and seedlings germinate and grow better amongst rough
surfaces. Recommended species, based on trials at Stockton and Strongman are:
manuka, Phormium cookianum, mosses and vascular herbs such as Nertera depressa,
Epilobium species, and Anaphalioides bellidioides, with fertiliser. No exotic grasses,
clovers or lotus will be included in hydroseeding mixes used at Te Kuha, with the possible
exception of soil stockpiles which may be sown with a sterile cereal or annual grass to
reduce erosion, if natural cover is unacceptably low and the erosion risk is high.
5.7
Rehabilitation Procedures for Specific Landforms
5.7.1
Haul Roads
Low Altitude Sites
Mine opening begins with the development of the access road from the Nine Mile Road
to the Te Kuha site. The road traverses river terraces with tall forest which are
characterised by relatively deep soils.
As part of final route selection the edges of the road will be well defined. The route will
be chosen from within the agreed envelope so as to reduce effects on local habitats.
Road fill batters and permanent stockpiles of surplus overburden from the road will be
rehabilitated using direct transfer that focuses on individual root plates within tall forest
and areas with a dense understorey of species that will tolerate open sites. This will be
supplemented by intensive hand transfer of seedlings and fascining with seed-bearing
branches of manuka if required.
Wood and rocks are likely to be used to help create a stable, rough surface where the
initial cover of live vegetation is low. Hydroseeding may be used as a supplementary
treatment on cut batters which are too steep or too lacking in soil for other treatments to
be successful. Direct transfer and rock will also be used to cover the outer edges of road
safety bunds, to form a barrier to weeds that may be brought up the road on vehicles and
to minimise sediment generation.
Cut batters will be as steep as is geotechnically stable, depending on local conditions, in
order to minimise the road footprint. Batters will be cut with rough surfaces. It is expected
that with suitable weed control the predominantly shaded aspect of cut faces in tall forest
will create an environment suitable for hydroseeding and natural establishment of
mosses, ferns and creeping herbs.
Higher Altitude Sites
Closer to the mine site vegetation comprises mostly coal measures shrubland and low
forest, where soil depth and fertility is more variable and plants are amenable to high
quality direct transfer. At these higher elevations soil quantity may be limiting at some
locations and some vegetation can be directly transferred by machine to shallow road
batters or cuttings.
Because the road is constructed in the first year and has a relatively narrow footprint,
intensive and direct transfer can be used on fill batters to achieve a fast, diverse,
vegetative cover at higher altitudes. Again, hydroseeding can be used in areas too steep
or lacking in soil for other treatments. In higher-altitude areas where the road batters are
low the vegetation and soils in the outer 2 to 5 m of the road footprint may be able to be
peeled back from the subsoil with bulldozers to create windrows that can be pulled over
the bottom edge of the fill batters with a backacter once the road has been formed. This
technique is sometimes used in pipeline construction. Once rehabilitated, fill batters will
generally not be re-disturbed.
5.7.2
Decommissioning of the Haul Road AND ROM
The main haul road will be decommissioned in two stages once it is no longer needed
for access to the former mine site for rehabilitation.
Stage One
Stage one rehabilitates most sediment ponds, water tables, and up to 20 m of road width.
A 4 to 5 m wide road (including water table or drainage controls) for light 4WD vehicle
access would be retained. Rehabilitation of the road will be influenced by the nature and
pattern of the adjacent landscape as well as the possible need to control runoff. Parts
of specific, highly visible, rehabilitated cut batters may be pulled down to angle of repose
slopes and covered with 100 to 200 mm of favourable overburden and soil, with plants
established by hydroseeding and/or planting to mitigate visual impacts. In other specific
areas where connectivity is particularly important and water tables allow, the surface next
to the cut faces may be built up using overburden with 100 to 200 mm of favourable soil
and plants from old roadside stockpiles. Any old roadside stockpiles utilised in this way
would then require rehabilitating.
The ROM area will be dismantled: the portable buildings will be removed, and any
contaminated substrates excavated and buried within the former pits prior to the
completion of final landform. Any concrete will be removed, the surface cross-ripped and
mounded to relieve compaction and create rough surfaces for vegetation. A drainage
pattern will be established to achieve controlled discharges of water from the area. The
surface will be covered with stockpiled soil and planted with nursery-raised and/or
salvaged seedlings from the stockpiles (which will have grown for 15 or more years by
that time).
Stage Two
The road will not be fully rehabilitated for at least five years after closure, as it provides
access for monitoring, maintenance and pest control activities. When the road is fully
decommissioned, the surface will be rehabilitated by spot-mounding (to 300 to 500 mm
depth at 2 to 3 m spacing) to allow root penetration, roughen the surface and retain water
for plant growth. Topsoil may be placed over up to 50% of the treated surface; natural
regeneration from adjacent vegetation is expected to effectively revegetate these small,
sheltered areas. Weed control will probably be needed until native seedlings are at least
0.5 m (near mine site) to 1.5 m in height (near the lower slopes)..
5.7.3
Overburden Placement Area and Backfilled Pit
The overburden placement area and backfilled pit will be rehabilitated to shrubland/forest
ecosystems. As well as vegetative rehabilitation, hydrological rehabilitation is also
required, including reinstatement of catchment headwaters as required by condition X.
Ecological connectivity across the site and landscape-level visual mitigation that
integrates the site with natural landforms are also key requirements of the rehabilitated
landform.
The fastest revegetation is achieved where wind exposure is low, surfaces are stable,
and substrates are soil-like. To this end all topsoil will be salvaged with forest duff and
slash.
Preferred planting mediums are:

Topsoil mixed with duff and vegetation is the preferred medium. Adequate
topsoil is planned to be stockpiled to cover all planted surfaces. Condition X
provides for a minimum of 100 mm of topsoil for forest and shrubland
rehabilitation.

Non-Acid Generating Overburden is likely to be used as replacement
‘subsoil’ to provide rooting depth to increase plant stability and store/supply
nutrients, particularly for taller forest areas. Many of the natural subsoils do
not support plant roots and these will not be salvaged or used.
Acid Generating Overburden will be disposed of within the former pits within saturated
backfill and will be covered by at least 2 m of non-acid generating overburden and a 100
– 300 mm layer of topsoil to provide a growth medium.
Shrubland and Forest in Overburden and Soil Stockpile Areas
Overburden placement areas, soil stockpiles and backfilled pit areas which are to be
rehabilitated to shrubland and forest will have substrates with:

Minimum 100 mm depth of topsoil replaced on all surfaces.

Up to 700 mm of replaced subsoils, or root-favourable overburden (e.g.
Quaternary colluvium, granite) depending on the landform and desired
vegetation. Some areas of direct transfer will have no subsoils to retain
shallow rooting depths to which the low-stature, water-tolerant ecosystems
have adapted. The greatest total root-favourable depth of replaced materials
will be on backfilled overburden where forest is rehabilitated and the least rootfavourable depth on angle-of-repose batters along the haul road.

Minimum 1.5 m of chemically favourable, non-acid generating overburden
immediately beneath the ‘soil’ layers. With the ‘subsoil’ layer, this will form a
minimum 2 m deep NAF cap over any hostile materials. This cap has low
permeability.
The minimum soil depth for forest provided for in this plan was identified as being both
functional and practical. Coarse wood and boulders/rock will be used to increase the
diversity of sheltered micro sites along with typical hump-hollow soils in some shrubland
and forest areas. The logs may provide inoculates of invertebrates and fungi and will
establish invertebrate habitat and diverse seedling establishment sites. The maximum
coverage of logs that creates effective habitat, while providing enough planting sites and
ready foot access will be determined on site.
Some areas of backfill in the southern part of the mine footprint will have a rehabilitated
subsoil of granitic overburden – these areas will be planted with a higher density of red
beech.
Top of the Overburden Landform
An alternative treatment will be used along the new ridgeline to assist with blending in to
the existing landscape. Placing large weathered boulders over compacted overburden
with small pockets of planted topsoils is likely to maintain an open, rocky landscape in
the medium term. A limited rooting depth, high water table and shearing winds is likely
to enforce sparse pockets of low vegetation.
Embankments ≥ 20 degrees slope
Some backfill areas over 20° slope will be mulched with gravels and rocks after topsoiling
to minimise mobilisation and movement of sediment adjacent to particularly sensitive
areas. This procedure mimics natural gravel surfaces near the northern end of the
existing ridgeline. Such areas will be planted with seedlings of suitable species.
5.7.4
Soil Stockpiles
Once the stockpiled soils have been removed the soil stockpiles will be rehabilitated by
scarifying the base layer, then planting and/or seeding (fascining, hydroseeding and/or
mulching) where residual soils are greater than 80 mm depth (about the height of pots
or root-trainers used for nursery-raised plants). Bunds (which wil have been vegetated
for up to 20 years) will be selectively pulled into the soil stockpile footprint, maintaining
live vegetation in a ‘direct transfer’ approach, and water tables will be reinstated. The
range of soil depths and drainage will help produce a variable height of plant cover.
5.7.5
Stream Diversion Channels and Banks
The headwaters of Coal Creek will be diverted around the pit edges as the pits are
created. The new channels will be backfilled with a minimum 1.5 m of non-acid-forming
rock to reduce sediment generation. This will create a very shallow (approximately 100
mm deep) base-flow of water over bedrock in a channel lined with weathered quaternary
and granitic boulders and stones.
At the completion of mining new channels will be created to feed into existing headwater
tributaries.
5.8
Forest and Shrubland
In the medium term manuka, flax, Olearia, hebe, Dracophyllum and broadleaf are likely
to dominate the vegetation in planted areas.
A mosaic of varying heights of forest and shrubland will be established by replacing a
minimum 100 mm of topsoil over variable depths of favourable rooting material to create
a range of soil drainage conditions. This variation will be established using a relatively
uniform blend of seral shrubland plant species. The underlying overburden, where not
deliberately loosened, will generally have low permeability and act as a root barrier.
Variation in soil drainage will be further accentuated by a variety of backfill slopes, with
poor drainage on low slopes and where the slope angle changes from steeper to flatter.
Variations in drainage will promote local variation in canopy dominance according to
species tolerances. A minimum density of beech and podocarp species will be planted
in areas with better drainage and deeper soils.
Manuka will be used extensively on all areas intended as shrub or forest, because it
colonises a wide range of substrates and micro sites. Manuka will be established using
seedlings and fascining.
Nodes of vegetation will be established using direct transfer. Higher proportions of
astelias, gahnias, wire-rush and forest tree seedlings are expected in these areas, with
Paesia, Histiopteris incisa and Blechnum ferns and herbs likely to naturally colonise more
sheltered areas, particularly at lower altitude, more protected locations.
At higher, more exposed sites, rehabilitation will be by planting and seeding (fascining,
hydroseeding and/or mulching) appropriate low-growing species into suitable soils with
boulders and rock mulch , to encourage the uneven, low cover characteristic of coal
measures.
5.9
Herbfields, Tarns and Banks of Streams
The existing channels are shallow, typically less than 1 m wide and 1 m deep and
generally surrounded by shrub vegetation that shadies the channels. The construction
and configuration of channels including banks and riparian zones will be specified in the
Construction and Earthworks Management Plan.
Once the channels have been
constructed, the margins will have vegetation directly transferred, if suitable material is
available. Alternatively margins will be planted with vegetation suitable to the terrain and
surrounding rehabilitation type. Attention will be paid to creating favourable habitat within
the streams for bryophytes and stream fauna by creating shade and by the placing of
rocks and boulders and the “transplanting” of bryophyte-covered rocks from existing
stream channels of the same type. Checks of stream water pH and light will be made to
determine when such transplants should be carried out.
The channels of stream diversions will not be formally revegetated as soil will not be
placed in areas affected by regular floodwaters. Light vehicle access to stream
diversions will likely be required to remain until mine closure, when it will be rehabilitated.
5.10
Boulders and Rock Piles
Boulders and rock piles provide habitat for lizards. During rehabilitation attention will be
given to creating such habitats where practicable. On that basis areas more than 100m2
that have up to 70% rock cover and as low as 30% vegetation cover represent an
acceptable rehabilitation outcome.
Conditions XX require the rehabilitation management practises to adhere to the following
rules:

Progressive rehabilitation of all disturbed areas, as areas are made available.

All topsoil and forest duff will be salvaged from areas to be disturbed prior to
mining.

Direct transfer methods of rehabilitation will be undertaken wherever
practicable given the characteristics of the land.

Existing vegetation will be translocated by direct transfer to the banks of new
stream channels where practicable.

Wetland herbfield vegetation will not be buried or destroyed and will be stored
and used for later 'seeding' or nucleus establishment within the rehabilitated
vegetation. There is approximately 800m2 of this vegetation.

Where new seed and plant resources are brought onto the site these shall be
sourced from the Ngakawau Ecological District from at least 500 m asl.
Rehabilitation will also be based on the following principles:

Smallest practicable footprint. Avoid disturbance outside the mine footprint
and maximise natural colonisation by establishing dense, weed-resistant
vegetation along roads, vulnerable rehabilitated ecosystems (herbfield) and
the site boundaries (refer to the Boundary Effects Management Plan if there
is a separate one, otherwise include here).

Salvage and conservation of soils, vegetation, wood, and invertebrates. This
is maximised by minimising the volume of material stockpiled, using minimaldisturbance stripping and stockpiling techniques that retain functional clumps
of intact plants and soils, separating topsoil from subsoil before stockpiling,
and scheduling stripping operations to provide access and time for salvage.

Constructed landforms that include valley, ridgeline and hill features. This
provides a physical basis for long term vegetation height and species diversity
by creating gradients of drainage, water supply and exposure.

Rough surfaces and favourable depth and quality of substrates. Such
conditions favour establishment and growth of a sustainable vegetation cover.
In particular use of topsoil and favourable ‘subsoil’ conditions accelerates
natural processes of succession.

Local native species and locally sourced genetic material. Exotic species will
not be established (possible exception being erosion control on soil stockpiles
and cut batters) and management will minimise the establishment and seeding
of weeds (refer Weed Management Plan or Section XX below).

Best practice stripping, stockpiling and revegetation with continual
improvement based on monitoring of rehabilitated areas.
The management practises associated with the identification, prioritising, salvage,
stripping and stockpiling of soil, vegetation and other rehabilitation resources such as
logs and weathered boulders are outlined in Section 5.X, as per condition X.
5.11
Propagation Nursery
Selection of nurseries to supply plants for revegetation at Te Kuha using genetic material
sourced from the footprint will be required. An on-site propagation area should be
established in the first 2 years at the mine site in order to efficiently provide guaranteed
locally-adapted seed, cuttings and divisions for propagation of plants by nurseries. This
is a successful model developed at Stockton Mine.
Seed or cutting material will be collected from the Te Kuha site, and potentially also within
Ngakawau Ecological District above 500 m (for rehabilitation of the main site), to send to
propagators.
Species that are likely to be propagated as nursery plants, or for seed include:
Ozothamnus leptophylla
Coprosma lucida
Coprosma foetidissima
Coprosma propinqua
Dacrycarpus dacrydioides
Dacrydium cupressinum
Epacris alpina
Fuscospora fusca
Fuscospora cliffortioides
Gahnia spp.
Gaultheria spp.
Griselinia littoralis
Hedycarya arborea
Leptospermum scoparium
Lophozonia menziesii
Metrosideros parkinsonii
Metrosideros umbellata
Olearia colensoi
Phormium cookianum
Phyllocladus alpinus
Quintinia acutifolia
Veronica odora
Weinmannia racemosa
This list may be expanded.
6.
WEEDS AND PESTS
6.1
Introduction
Prior to mining and mine exploration, the main Te Kuha site (excluding the coal loading
facility) was substantially weed free and preventing weed establishment is seen as a key
strategy to mitigate adverse effects of mining on the surrounding ecological communities
and to achieve desired successional trajectories.
After the commencement of road construction and mining and throughout mine life at the
Te Kuha site there is potential for weed species to colonise both disturbed and natural
areas. Weeds degrade natural communities and can make the habitat less suitable for
native species by increasing fertility (e.g. nitrogen fixing plants), physical smothering or
competition for space or by releasing growth-limiting substances. Both weeds and pests
have the potential to inhibit successful rehabilitation of the mine site to a native vegetation
cover, and adversely affect native species diversity and abundance if they are not
effectively managed.
Weed control is required by the conditions to operate Te Kuha Mine (given in Appendix
1) to protect the remaining habitat and aid rehabilitation of the site. Condition X makes
specific reference to the closure requirements for weed species.
A narrow range of woody and herbaceous weeds are present in and around the coal
processing and loading area near Nine Mile Road. The density of pests remains
unknown, but is likely to be low based on observations in the area (Mitchell Partnerships
2013).
Conditions XX of the resource consent require the survey and identification of non-native
plant species, including pest plants and animals, control of weeds and pests at each
mine planning stage (especially with respect to cleaning vehicles and earth moving
machinery, ensuring any bulk materials such as gravel brought onto the site are clean,
and that any non-native seeds or erosion-control materials used are not contaminated
with weed species) and specific standards for control of identified (key) species such as
gorse and broom.
Condition X of the resource consents requires:

An identification of the key weed species and the management principles adopted
in the mine planning stages with respect to weed control, and the risks and
contingency measures in relation to weeds. This includes the means by which
earthmoving machinery and equipment (including vehicles used in rehabilitation
at the mine site, particularly hydroseeding and mulching machinery) will be
cleaned prior to their removal from the Te Kuha mining areas, and also the means
by which nursery grown seedlings will be delivered to site in a weed and pest free
state.

The means by which weeds will be controlled and closure targets for weeds met
during all stages of mine life, with particular reference to gorse, Juncus
squarrosus, broom, Asiatic knot weed and any woody weed species.

Monitoring, including trigger points for active intervention.

The mine closure targets for weeds are set out in condition X. For all landform
types the criteria are [TBC]:
These matters are discussed in more detail below.
In recognition of the potentially significant adverse impact pests could have on the
rehabilitation efforts, specific management of pests and weeds is proposed as follows.
6.2
Key Weed Species
Gorse and broom are currently absent from the mine site, however gorse is present along
Nine Mile Road and on farmland adjoining the lower slopes at Te Kuha. The opening of
an access road will provide an opportunity for gorse and other undesirable species to
colonise any disturbed ground such as the road edges and the mine site itself.
Broom, willow (Salix spp.), Asiatic knotweed (Fallopia japonica), Himalayan honeysuckle
(Leycesteria formosa), Spanish heath (Erica lusitanica), montbretia (Crocosmia x
crocosmiiflora) and butterfly bush (buddleia, Buddleja davidii) are present as isolated
populations on the Buller River terraces and / or along the edge of Nine Mile Road and
could potentially colonise the Te Kuha site.
The other main potential weed present in the broader area, and in localised areas across
the Stockton and Denniston plateaux is Juncus squarrosus, an exotic rush species that
colonises open disturbed areas and forms tight low-growing mats (to about 500 mm).
As J. squarrosus is very short and does not fix nitrogen, it is unlikely to facilitate invasion
of other weed species, but may suppress regeneration of native herb species in open
environments such as herbfields and stream beds. J. squarrosus appears to trap
sediment, and stabilise eroded surfaces at Stockton and Millerton, so may facilitate
succession to woody species by promoting stability and increasing organic matter in the
substrate. J. squarrosus mainly regenerates from seed. Since it has not been found at
Te Kuha is unlikely seeds would be present in stripped soil, but seeds and buried
vegetation could be brought to the site attached to earth moving equipment or vehicles
which have been used elsewhere. Other exotic species may also colonise wet areas
including Juncus canadensis, Juncus bulbosus and small herbaceous species.
Pasture legumes (e.g. Lotus and Trifolium spp.), pasture grasses (e.g., Yorkshire fog
(Holcus lanatus), browntop (Agrostis spp.)) and pasture weeds (such as foxglove
(Digitalis purpurea) and ox-eye daisy (Leucanthemum vulgare)) are also potential local
weed species along with large fireweeds (Senecio and Conyza spp.) and roadside weeds
such as Himalayan honeysuckle (Leycesteria formosa) or pampas, (Cortaderia selloana,
C. jubatus) and wind-blown pasture weeds of roadsides such as catsear (Hypochaeris
radicata) and the like.
Other potential weed species are commonly found with nursery raised plants, such as
oxalis (Oxalis spp.), milk weed (Euphorbia peplus), Epilobium ciliatum,, popping cress
(Cardamine spp.) and some liverworts/mosses.
Most of these weed species are not competitive in closed forest or acidic, low fertility
ecosystems. The most vulnerable rehabilitated ecosystems are therefore short in stature
– tarns and rocklands or where fertility has been enhanced (e.g. with fertiliser).
Te Kuha also provides high quality bryophyte (moss and liverwort) habitats and is home
to at least 12 threatened or at risk species (Mitchell Partnerships Limited 2016).
Bryophyte weeds occupy space and reduce habitat for native bryophytes and are of
concern for that reason. Bryophyte weed species of concern include Sphagnum
subnitens (weasel moss) and Racomitrium elongatum. Bryophytes can be spread by
tiny leaf fragments, and R. elongatum appears to have been spread by council mowers
that mow the grass road verge at Denniston. There is no proposal to mow the edges of
the Te Kuha access road.
Vigilance will need to be maintained to ensure that weed species new to the area do not
colonise the site. Any vehicles, machinery, clothes or boots that have been at Denniston
or Stockton will have to be cleaned to a very high standard before entering the Te Kuha
site. Vehicles and materials used for erosion control, hydroseeding or sediment
pond/water table maintenance elsewhere pose a particularly high risk since they travel
off-road.
6.3
Objectives of Weed Control
The objectives of Weed Management and Biosecurity at Te Kuha are to:

Prevent the establishment of new weed species within the Te Kuha Mine area
as defined.

Minimise the spread of weeds on disturbed and undisturbed areas within the
greater mine area.

Maintain the distribution and abundance of weeds at the site at very low levels
so that weeds do not impair natural succession of native vegetation cover in
the medium to long term.
Note that non-native species that do not pose a particular threat to the establishment of
the native vegetation required will not be specifically targeted unless they develop
colonies of a size that impedes native vegetation development (for example, Agrostis
capillaris, Lotus pedunculatus, Juncus bufonius, J. bulbosus and J. planifolius).
6.4
Management Procedures
6.4.1
Weed Control
Weed control measures are based on the two principles:
1. Preventing establishment of new weed species and populations. This involves
site hygiene and measures to prevent propagules arriving on site and site
management to reduce suitable habitat for weeds that breach the borders.
2. Minimising the spread of weed populations within the site. This involves mapping
known weed populations and systematically monitoring their spread and
preventing their growth and reproduction.
Both of these principles must be incorporated into mine planning in order to achieve the
standards required for mine closure to be achieved. Mine planning explicitly allows for
the salvage of soil from the Te Kuha Mine area and its storage for reuse in rehabilitation.
Nearly all the soil storage areas selected are in locations that contain sparse weed
populations in order to minimise the potential for weed spread, but storage of large
amounts of soil provides considerable opportunity for weeds to invade.
The following principles will apply:
i)
The use of direct transfer as the first priority rehabilitation method since this
minimises the open areas available for weed colonisation and does not introduce
new material to the site.
ii) The use of biomass (felled trees and branches collected locally) across the areas
ready for rehabilitation (after backfilling and soil spreading). This will minimise
the area of bare substrate that weeds might otherwise colonise and provide for
inoculation of local biological materials.
iii) The planting of native species as soon as possible after biomass is spread
allowing them to get a “head start” over the weeds. Close planting can be adopted
in areas vulnerable to weed invasion or erosion.
iv) The use of uncontaminated soil excavated from the mine footprint as a substrate
which will minimise the potential for weed infestation and maximise the growth of
the planted seedlings (allowing them to outcompete weeds).
v) The soil stockpiles created by the mine excavation will be inspected regularly for
weed seedlings and these will be removed or sprayed. Soil likely to be
contaminated with weed seeds will be stockpiled separately and used as fill
(rather than surface substrate) to prevent seed germination.
vi) Regular (six monthly) inspection for weeds of the quarry sites where gravel is
sourced for roads and treatment of same.
vii) Regular (six monthly) inspection of road surfaces and edges, including sediment
ponds/water tables and their discharge points to identify and remove weeds as
they establish.
viii) Prompt rehabilitation of road batters, using direct transfer of dense vegetation
where possible or by planting densely to crowd out weeds.
ix) Provision of a vehicle wash at the coal load out. Vehicles leaving or entering the
load out would be washed to remove any seeds or other material. Vehicles
remaining on the mine site would only need to be washed upon first entry.
6.4.2
Preventing Establishment of New Weed Species and Populations
Since the existing (2017) weed density is low, the most effective weed control method is
prevention of colonisation from other, weedier, areas either adjacent to or distant from
Te Kuha. Because the mine operation involves movement of soil and biological material
the potential for invasion is relatively high and vigilance will be needed to ensure weeds
do not establish. In particular the appropriate salvage of material and propagation of
plants will contribute to successfully preventing weed establishment.
The following weed control methods will be adopted:
i)
Prior to the commencement of construction of the access road all gorse, Lotus
pendunculatus, grass and other weed species growing in the vicinity of the quarry
and at the entrance to the new haul road will be sprayed. This spraying will
continue at two monthly intervals so that these weeds are progressively
eliminated. This control programme will be continued until road construction is
completed in order to minimise the potential for seed transport from the quarry to
the mine.
ii) Prior to the commissioning of the access roads to the mine a wheel wash will be
provided to wash vehicles entering the site from Nine Mile Road.
iii) Prior to the commencement of the construction of the road, all earthmoving
equipment and vehicles to be used during construction will be washed to remove
seeds and soil
iv) As the road is constructed all road batters and stockpiles will be vegetated or
covered with weed-free mulch in order to remove potential substrate for weeds.
Drains and the like will be lined with rocks for similar reasons. Prior to the
commencement of any activities at the Te Kuha Mine site all weed colonies along
the road leading into the area will be sprayed or removed in an effort to remove
satellite populations which may be an ongoing source of seeds.
v) Rock for the haul road surface will be sourced from the weed-free quarry areas
only, with no rock material sourced from river terraces or other areas near the
Buller River.
vi) Haul trucks operating between the mine and coal load out sites will be washed
thoroughly before they first enter the site. Provided they remain on the main haul
route they will not require a wheel wash on each entry to the site; but should they
work in other areas they will be washed down again prior to re-entering the Te
Kuha site.
vii) A wash down area will be provided for the cleaning of machinery used for
rehabilitation activities before entering the mine.
viii) Sediment from the vehicle wash-down and from road water tables and drains will
regularly be removed from the site or placed deep within the fill zones (i.e., not
near the surface) as these are likely to contain weed seeds.
ix) No soil will be transported to Te Kuha for use in rehabilitation to minimise the
potential for weed introduction.
x) An effective weed control strategy will be part of the supply contract for nursery
plants and penalty provisions will apply if plants supplied are shown to be carrying
weeds or weed seeds. Nursery hygiene standards will minimise contamination
of seedlings and growing media brought onto the site and nurseries must be kept
clean and free of weed species.
xi) Any plant storage area at Te Kuha from which plants may be spread around the
site will be maintained free of weeds. Plants salvaged from the site may be stored
on site, but if taken off-site and returned, nursery hygiene standards will apply.
6.4.3
Minimising the Spread of Weed Populations within the Site
Inevitably weed seeds (or possibly vegetative material) will reach the Te Kuha site,
despite the hygiene precautions above. In order to prevent the establishment of new
species and the spread of resident weeds, the amount of suitable habitat for weed
establishment will be minimised by:
i)
Adopting rolling rehabilitation (leaving minimal areas exposed at any one time).
ii) Quickly establishing dense rock, wood and / or vegetative cover on vulnerable
areas and/or those subjected to high weed pressures, e.g., along the main haul
road, roadside drains. Establishing rapid vegetative cover in these zones will be
achieved by using direct transfer wherever possible and by placing the most
favourable substrates for plant growth there (soil and rock with a pH>4.5).
iii) Preferentially using herbicides and cutting/painting rather than hand pulling to
minimise surface disturbance and the potential exposure of weed seeds and
favourable sites. Herbicide application will be carried out in such a manner that
it is limited to the weed plants being targeted.
iv) Adopting planting densities that achieve full native vegetation cover of soils as
soon as possible (target within ten years). Plant densities may be increased to
minimise weed spread in vulnerable areas.
v) Maximising the flow of native seed across the site by avoiding disturbance outside
the mine footprint and ensuring that vegetation adjacent to the active mining and
operational areas is healthy.
It is expected that by planting desirable seedlings to establish a dense cover > 1 m height
as soon as possible, weed colonisation should be minimised in shrubland areas by
reducing light at the surface in the short to medium term.
In wetland herbfields Juncus invasion will be limited by establishing dense vegetation to
minimise areas of bare soil, combined with surrounding them with a buffer of direct
transfer vegetation and rock cover within the (small) catchment and minimising throughflow of water to prevent seed movement into such areas.
6.4.5
Weed Control
Effective weed control requires identification of weed species, locating individual colonies
and then extermination of the weeds using appropriate methods followed by revegetation
with desirable plants and monitoring to ensure the weeds do not return. Because
identification is a key step in the process of weed control, professional contractors or
staff with experience in weed identification will be used to implement this management
plan.
Te Kuha Limited Partnership will put in place a spray programme to control gorse and
other weeds throughout the site, including the access road. Control of rushes, including
J. squarrosus, will mainly be by application of herbicide spray. Trials of glyphosate under
various treatments were carried out by Landcare Research and the Department of
Conservation in 2004 and the results indicate that glyphosate at recommended rates is
effective at killing the plants within two months. Gorse is controlled by the application of
herbicide (Metsulfuron-methyl and others) too, but a wetting agent and penetrant (such
as organosilicone) are also required.
There are a number of management techniques that improve the success of weed control
and provide a degree of certainty about the outcome of a weed control programme. The
spread of weed populations within the Te Kuha site will be minimised by:
i)
Mapping and identifying weeds in areas due to be stripped. These weeds will be
killed before stripping and the soils and vegetation quarantined (separately
stripped and stored) with other weedy soils.
ii) Annual mapping of known weed colonies throughout the mine area and haul road
route.
iii) Monitoring of weeds and undertaking weed control before seeding. Gorse and
broom have yellow flowers, making their identification relatively easy.
iv) Reviewing monitoring data and maps to identify the most vulnerable areas,
probable weed sources and flows, and adjusting the monitoring regime to allow
detection and treatment of weeds in these areas before they set seed.
v) Undertaking rehabilitation monitoring and inspection. In order to minimise the
establishment of gorse, broom, Asiatic knotweed, Juncus squarrosus and Juncus
canadensis on rehabilitated areas inspection staff will routinely carry herbicide
wands, so these plants are treated as they are identified, weather permitting. The
location of these plants will be mapped as part of the monitoring programme to
allow identification of at risk areas.
vi) Restricting vehicle movements to those associated with the mining activities.
vii) Annual checks for gorse and hand pulling or spraying will be carried out as
appropriate on the undisturbed ground near roads and working areas.
viii) Annual mapping and spraying of exotic Juncus species
ix) Minimising the amount of disturbed ground at any one time during construction
activities. Vegetation and soils stripped ahead of road construction will be used
either in direct transfer or as jumbled ground cover (mixture of soil and
vegetation). Road edges (including any sidecast materials) will be revegetated
as soon as practicable using soil and vegetation material stripped as part of the
road construction where possible in order to cover any areas of exposed soil.
x) Where areas of weeds have been sprayed, replanting the area with desirable
species as the weeds die. This helps prevent other weeds establishing on the
cleared ground and minimises the amount of work required to keep weeds at low
density.
6.4.6
Monitoring
Regular monitoring of the Te Kuha site will be carried out as follows:

The quarry sites where gravel is sourced for roads will be inspected for weeds at
two monthly intervals and any weeds found will be treated with herbicide.

During the construction of the road, and for one year after its completion, the road
surface, batters and drains will be inspected for weeds at two monthly intervals
and any weeds found removed before seeding.

Monitoring will be carried out six-monthly in all areas of active operations and
active rehabilitation. This will include spot treatment of weeds when found. All
weeds found will be mapped on aerial photos of the area so as to acquire
knowledge about where weeds are most likely. In order to ensure all areas
receive equal search effort (at least initially) the aerial photos will be divided into
grids and each grid square will be extensively searched. Each grid square will
be numbered and a record kept of the search effort, weeds detected, herbicides
applied (or other control method), species planted and subsequent follow up. Key
areas for searching include those that experience heavy traffic volumes, are close
to a source of weeds, have been rehabilitated or were devoid of vegetation for a
period.

Monitoring of weeds in newly rehabilitated areas will be carried out until the
vegetation has established a full cover or there has been no recruitment of weeds
over four monitoring periods (two years). In “high risk” areas monitoring will be
six monthly and in “low risk” areas it will be annually. High risk areas include the
edges of water courses, within 50 m of roads, in areas rehabilitated with topsoil
which is known or suspected to contain weeds, and rehabilitation areas with
nursery plants less than 18 months old.

The soil stockpiles created by the mine excavation will be inspected monthly for
weed seedlings and these will be manually removed or treated with herbicide.

Weed monitoring and control will then be carried out two-yearly until a period of
XX years has elapsed since the rehabilitation was carried out, or until the closure
criteria specified in condition XX have been met.

The mine area will be divided into monitoring blocks to ensure that each is
monitored appropriately over the life of the mine and until XX years after mining
has ceased. The area can be divided into low, medium and high risk areas of
weed presence for this purpose.

During monitoring surveys a weed wand will be carried to enable isolated plants
to be treated on the spot.
6.4.7
Closure Targets for Weed Species
On all landform types the closure targets for weed species are 0% visible flowering or
seeding cover and <5% mean cover per plot, with no plot greater than 10% cover. These
standards are to be achieved and maintained for a minimum period of three years prior
to closure (as per condition X):
The above criteria will be measured in randomly located plots (quadrats) stratified by
landform, and may be stratified by age. When quadrats are viewed from above the %
cover is defined as the percentage of the ground within the quadrat which is occupied by
the above-ground parts of each species.
In addition – conditions for rocklands and tarns…[TBC]
6.5
Pest and Predator Control
6.5.1
Key Pest Species
Introduced grazing animals and predators are present at the proposed Te Kuha Mine but
their density remains unknown. Even a low density of predators can have a
disproportionately high impact on species that are specifically targeted and/or slow to
reproduce. Animal pest species present on the site may include:







Stoats.
Possums.
Hares.
Deer.
Dogs.
Wasps.
Rats and mice.
A Te Kuha Mine rule will prohibit dogs (other than trained kiwi dogs) being brought onto
the site. Possums, deer and hares are potential pests with regard to rehabilitation
because they periodically browse planted seedlings of rata, kamahi, tussock, toetoe and
Coprosma spp. and other species and reduce the efficacy of revegetation. The weed
and pest plan outlines weed and pest control required.
Pest control must continue for XX years following the cessation of coal extraction
(condition X).
The purpose of predator and pest control is to maintain wildlife present prior to the
commencement of mining in the area so that sufficient individuals are available to
recolonize the mine site as habitats become suitable and in addition prevent herbivores
such as hares or deer from compromising rehabilitation efforts by killing or otherwise
affecting newly planted vegetation. The specific objectives of predator control are:
(1)
To enhance the survival rates of roroa, lizards, forest birds and other native
wildlife within the XX ha Te Kuha Biodiversity Enhancement Area (“TBEA”)
shown in Figure 1 for the life of mining operations at Te Kuha and for a period
of XX years after rehabilitation is completed.
(2)
To protect vegetation on the rehabilitated mine surfaces from browsing
mammals.
[Check consistent with conditions]
[To come]
Figure 2: The Te Kuha Biodiversity Enhancement Area
This plan provides for the following:
(a)
The means by which the Consent Holder shall control rats, stoats and
possums in the TBEA to low levels consistent with improved breeding
success for the target native species.
(b)
Intervention triggers which ensure predator management is timely and
effective at reducing predator densities.
(c)
Monitoring to ensure the Consent Holder is able to demonstrate compliance
with the requirements of the Predator Management Plan and conditions XX of
the relevant resource consents.
6.5.2
Consultation and Reporting
Consultation
Prior to this plan becoming operational the details will be confirmed with the Department
of Conservation. Consultation with the Department of Conservation is required if there
are proposed changes to this plan, and the Consent Authority (Buller District Council)
will be advised of any changes that are made.
Consultation with the Department of Conservation regarding pesticide use on areas of
public conservation land and applications for permission to apply Vertebrate Toxic
Agents (“VTAs”) will be required.
Reporting
Condition XX sets out the requirement for an Annual Environmental Monitoring Report
which will include the activities and monitoring carried out in relation to predator
management. The monitoring period to be included in each report is the 12-month period
ending two months prior to the anniversary of the commencement of these consents.
The report will be submitted to the Consent Authority and to the Peer Review Panel or
Technical Advisory Group [TBC] one month prior to each anniversary of the
commencement of the consents. The Department of Conservation shall also be provided
with a copy of the report.
6.6
Management Practices
6.6.1
Monitoring
Possums
The standard National Possum Control Agency (“NPCA”) Protocol methods for
monitoring possums (NPCA July 2008) use lines of leg hold traps. Lines of wax tags
markers have also be used successfully to monitor possum numbers. These methods
result in either a residual trap catch index (“RTCI”) number or similar bite mark index
(“BMI”) for the purposes of determining whether the operational target is being achieved.
The method of monitoring and the number of monitoring lines will be chosen in
consultation with the Department of Conservation once the size and location of the
management area is confirmed. Monitoring lines will be randomly located throughout
the TBEA.
The first round of possum monitoring will be undertaken prior to the commencement of
mining activities at Te Kuha and before any management controls are implemented.
Regular possum monitoring will take place at two yearly intervals to be timed between
November and May. After control operations an additional monitoring round will be
undertaken at least one month after completion the operation to confirm the operational
target has been met.
Rats
Tracking tunnels with ink cards will be used to monitor the abundance of rats in
accordance with methods approved by the Department of Conservation.
Lines of tracking tunnels will be put in place permanently and employed twice a year e.g.
August and February. If there is an increase in food source identified (e.g. during a
beech mast event) additional rat monitoring rounds will be completed in May and
November.
The number of monitoring lines will be chosen in consultation with the Department of
Conservation once the size and location of the TBEA is confirmed. Monitoring lines will
be located randomly throughout the area.
The first round of rat monitoring will be undertaken prior to the commencement of mining
activities at Te Kuha and before any management controls are implemented. Regular
rat monitoring will begin after the first control operation.
Other predator monitoring methods may be adopted if approved by the Department of
Conservation.
6.6.2
Beech Masting
Beech or podocarp species seed heavily only infrequently (in mast years). The
occurrence of beech and podocarp masting provides an early warning of an increase in
beech seeds and associated increase in rodents and higher order predators. In some
mast years rodent irruptions are triggered by the increase in food availability and these
are followed by stoat population irruptions a few months later.
The nearest beech seed monitoring site which collects data from seed fall between
March and June, is at Station Creek (in the Maruia Forest) located approximately 70 km
south-east of Te Kuha. However, beech mast data from Station Creek would only
become available after April – May. Therefore, liaison between TBEA managers and
Department of Conservation staff will be important to ascertain if beech masting is likely
to occur based on beech flowering during summer. If masting proves difficult to predict
using the above approach this will be reviewed and if necessary, local monitoring will be
put in place or other options considered and discussed with the Department of
Conservation.
6.6.4
Wasp Monitoring
High densities of introduced wasps (Vespula spp.) are a threat to populations of the
native forest ringlet butterfly (Dodonidia helmsii) which has a conservation ranking of “At
Risk (Relict)”. Te Kuha is home to a healthy population of forest ringlets and wasp control
is proposed to mitigate any adverse effects due to habitat removal (particularly of Gahnia
plants which are host to the ringlet larvae) if visual or bait line monitoring indicates wasp
densities exceed the target threshold of 0.75 wasps per bait as discussed below.
Visual monitoring will be undertaken fortnightly from early January each year as
follows:

Observers will walk through the area and record wasp presence or activity in the
area. If there are no wasps are recorded, no further action is required. If wasps
are recorded, wasp bait line monitoring protocol as described below would be
initiated.
Bait line monitoring: Monitoring would be undertaken in the middle of the day, between
11 a.m. and 2 p.m., and not in the rain. Fine, sunny weather is preferred. The method is
as follows:

Place a line of 20 plastic jam-jar lids out on the ground, 20 m apart, with one
tablespoon of tinned salmon (in spring water NOT oil) or sardine in aspic catfood.

Leave the lids in place for a period of 60 minutes and then count the number of
wasps at each bait (i.e. an instantaneous count when you first arrive at bait).

Calculate the total number of wasps on the line and then divide by 20 to calculate
an average per bait.
To monitor the wasp population three tests per year would be undertaken with the first
test in mid-January, the second in early February and the third test in late February/early
March. Bait line monitoring would only be undertaken if visual monitoring indicates visible
wasp activity.
6.6.3
Biodiversity Outcome Monitoring
Outcome monitoring will include the following elements:





Call counts for roroa
5 minute bird counts for forest birds
Lizard surveys
Forest Ringlet surveys
Bryophyte Monitoring
This monitoring will be carried out annually using the methods detailed in the Roroa
Management Plan, Appendix 4, the Lizard Management Plan respectively, the Forest
Ringlet Management Plan and the Bryophyte Management Plan respectively.
6.7
Intervention Triggers
6.7.1
Possums
An average possum density of greater than or equal to 5% mean RTCI or 12% BMI
possums with any more than two lines being greater than 10% RTC or 15% BMI shall
trigger possum control to occur across the TBEA shown in Figure 1. The RTC method
is that set out in Possum Population Monitoring using the Trap–Catch Method National
Possum Control Agencies April 2004, or any subsequent updated version of this
document.
6.7.2
Rats
A rat tracking index of greater than or equal to 5% of tunnels tracked or more than any
two lines being greater than 10% tracked shall trigger rat control to occur across the
TBEA shown in Figure 1.
6.7.3
Beech Masting
When monitoring at Station Creek (or other monitoring agreed with the Department of
Conservation) indicates a beech mast season is imminent, rodent control will be
implemented early (i.e. during autumn and winter) to prevent a build-up of rodent
numbers leading to an increase in stoat numbers.
6.7.4
Wasp Densities
Exotic wasps will be controlled when monitoring indicates the local densities exceed 0.75
wasps per bait as described in the bait line monitoring protocol in Section 6.6.4 above.
If bait line monitoring indicates an average density above 0.5 wasps per bait, wasp
monitoring should be repeated the following week in order to identify high densities and
initiate control as soon as possible.
If was densities meet or exceed 0.75 wasps per station, wasp control will be undertaken
with Vespex wasp bait as shown in the training video available at:
https://www.merchento.com/vespex-information.html
6.7.5
Biodiversity Outcomes
Bird call counts are naturally variable on a daily, seasonal and annual basis. For that
reason a decline in call counts in any one year should not necessarily be cause for
concern. If call counts for roroa decline for three years in a row the predator control
programme will be reviewed to determine how it can be improved.
6.7.6
Rehabilitation
If regular monitoring of the rehabilitated areas as prescribed in Section 7.1 indicates that
hares, deer or goats are compromising rehabilitation efforts or affecting plant growth,
management of these species will begin.
6.8
Integrated Predator Control Programme
6.8.1
Spatial and Temporal Integration
The predator control programme will cover the TBEA and the area surrounding and
including the mine itself as follows:

TBEA XX ha, targeting possums, stoats and rats.

Mine site control of possums, hares, and deer covering approximately 230
ha.
The four aspects of the predator control programme (possums, stoats, rats and wasps)
are intended to be applied in an integrated way and to be flexible, so that they can evolve
over time to accommodate new developments in control and monitoring techniques. In
addition, all four facets must minimise harm to non-target native species, since they will
be undertaken in the presence of a diverse mix of protected wildlife, including weka.
TB Free New Zealand and the Department of Conservation also carry out programmes
targeting possums and other mammals and their operations may include areas adjoining
or near the TBEA. If so, the TBEA programme will be integrated with any other
programme to ensure consistent and continuous coverage whilst ensuring that other
target species are included in each area as required.
It is most likely that trapping and poisoning using bait stations will form an integral part
of predator control at the TBEA. Aerial 1080 application is also a viable management
tool and the exact configuration and method of control will be decided in consultation
with the Department of Conservation and other experts once the size and location of the
TBEA is confirmed and the round of pre-mining monitoring completed.
All permits required from the Department of Conservation for VTA use on public
conservation land will be obtained and approval sought for any suggested changes to
the VTA (s) being applied. Permission from the Medical Officer of Health for application
of VTA will also be obtained.
Experienced operators will be employed to carry out the predator control and monitoring
operations
6.8.2
Control Methods
Possum and Rat Control
A network of bait stations will be used to control possums and rats.
Possum control operations will commence when possum monitoring indicates an
average of more than 5% mean RTCI or 12% BMI across the TBEA with any more than
two lines being greater than 10% RTC or 15% BMI as defined in Section 6.7.1 above.
Bait stations will be located at an average density of one trap per hectare. Current best
practice will be adopted at the time of any control which could include pre-feeding.
Rat control operations will be continuous with the target of maintaining ≤ 5% tracking
index.
Stoat Control
Stoats will be controlled mainly by intensive kill-trapping, supplemented with secondary
poisoning from bait stations. Kill-traps will be positioned at an average density of one
trap per 1.25 ha throughout the entire treatment area, at 100 m spacings, on marked
tracks cut along the contour (approximately XX traps). The type of trap currently
recommended by the Department of Conservation for use at the commencement of this
programme is the DOC 150 or DOC 200 set under a 900 mm wooden cover with a double
mesh entrance to exclude weka. The trap type may be changed in future if agreed by
the Department of Conservation. The traps will be baited with locally sourced noncommercial hen eggs or other suitable bait and operated continuously throughout the
year, with service rates determined by catch numbers (expected to be fortnightly
November to February and less frequently between March and October).
Baits, trap types and other aspects of predator management are subject to continuous
refinement and experimental testing of their efficacy by the Department of Conservation
and others in the field of predator control. Accordingly, trap type and layout, bait type,
service frequency and other aspects of stoat management may be progressively
modified according to the most recent information available at any given time. Different
baits and lures may be tested as better alternatives become available.
Herbivore Control
If hare, goat or deer control proves necessary then hares will be controlled by night
shooting between September and March, preferably on warmer nights and when mining
activity is lowest and therefore hare activity is likely to be highest. A spotlight and
shooting operation would be carried out by licensed operators, between dusk and 1 am.
Hares browse selectively on nutrient-rich foliage, and the operators may attract hares to
specially prepared “ambush” areas to increase the likelihood of a good knock-down.
Goats are not currently known to be active in the Te Kuha area but should they be
detected, a targeted hunting programme would be put in place. Deer are present in low
numbers in the site area. It is expected that when mining operations commence they
are unlikely to frequent the site, however a hunting programme would be implemented if
required.
7.
REHABILITATION MONITORING
7.1
Frequency and Timing of Monitoring
Condition X specifies that, as a minimum, monitoring of rehabilitation be undertaken
following establishment in each area and subsequently every three years. Mine
monitoring experience is that monitoring should be undertaken within three months after
initial revegetation has been carried out, then about one year after planting, and then at
three- to five-yearly intervals until closure standards are maintained and again at the time
the bond is released and this regime will be adopted. Monitoring data will be summarised
and interpreted annually as part of the annual Environmental Monitoring Report required
by condition X).
Regular monitoring of all rehabilitated areas will also include weed and predator
assessments, as per Section 6 above.
During mining, where necessary monitoring will also take into account the following,
since these factors also influence rehabilitation success:

Monitoring of salvage, stripping and stockpiling of rehabilitation resources,
specifically the volume of topsoil.

Monitoring landform formation, with special attention to the edges of the mine
landform to ensure continuity with the adjacent undisturbed topography

Monitoring of topsoil and root zone depth in rehabilitated areas, including
depth and permeability of the non-acid forming cap.
Essentially the monitoring of salvage, stripping, stockpiling, landform formation and
substrate placement will be undertaken in the form of check-lists and records kept in
accordance with the annual work plan. This monitoring is designed such that any
significant rehabilitation failure can be identified quickly and remedial action initiated.
With the exception of the initial and approximately three monthly assessment after
rehabilitation commences, monitoring will be conducted in comparable seasons,
preferably in autumn when growth during the previous summer can be assessed
(vegetation is generally established in late spring/early summer).
Parameters to be measured in planted areas in the first year include native planted
vascular plant density and mortality. In other areas, and in older plantings, native cover
and height, area of bare erodible substrate and species and cover of weeds shall be
recorded, iRecords of any animal browse will be kept.
The three month assessment allows corrective action within the same planting season if
necessary while access to the sites for intensive work is open if needed.
7.2
Intervention Triggers
Intervention triggers are given in Table 3 and may be amended based on site-specific
experience, subject to confirmation by the peer reviewer. Intervention treatments will be
targeted to address the cause of the failure.
Where plant mortality or density triggers intervention, actions to increase density may
include:

Additional planting or fascining with the same or different plant species.

Stabilising the soil surface by controlling the direction and intensity of water
flows, by Rock mulching or applying coarse wood of mulch to reduce surface
erosion.

Additional predator control of browsing mammals on the rehabilitated mine
surfaces.
Where low vegetation height or cover activates intervention, appropriate actions may
include:

Application of fertiliser in a slit near the base of responsive plants to stimulate
growth.

Planting of additional seedlings suited to the micro-climate.
Table 3: Short term rehabilitation aims (at time=0, 3 months, one year and three
years) and intervention triggers for the main landform and vegetation
types at Te Kuha Mine, 50 m belt transects 2 m wide = 100 m2 plots.
Vegetation Type
Forest/ shrubland
Short Term Aim
Trigger for Intervention
Landform - Backfilled Overburden
T = 0 (prior to vegetation):
Mean topsoil depth 100 mm.
Mean topsoil or rooting depth not
.
achieved.
Coarse wood & rock cover 5 - 40%.
Coarse wood or rock<5% cover.
T = 3 months, 1 year, 3 years:
Minimum density of planted or
regenerating seedlings 100/100m2.
Minimum 5 native species/100 m2
plot.
Forest/ shrubland
Native vascular plant cover, density
or height same or less than in
previous monitoring.
Less than 5 native vascular
species/plot
Visible weeds
Landform – rehabilitated using direct transfer
T = 0 (prior to vegetation):
Range of slopes and minimum depth NAF cap or permeability in lowof NAF cap achieved, permeability
slope areas not achieved
meets target for the ecosystem in
areas <10 degrees slope
Native vascular plant cover, density
or height same or less than in
T = 3 months, 1 year, 3 years:
previous monitoring.
.
Visible weeds
Vegetation Type
Shrubland
Shrubland
Note:
Short Term Aim
Trigger for Intervention
Landform - Cut Faces
T = 3 months, 1 year, 3 years:
Native vascular plant cover, density or
Minimum plant density 25/100m2.
height same or less than in previous
monitoring. Weeds present
Visible gorse, broom, pampas, Asiatic
knotweed, Himalayan honeysuckle,
Juncus squarrosus.
Landform - Soil Stockpiles after rehabilitation
T = 3 months, 1 year, 3 years:
Minimum plant density <2/m 2 where
2
Minimum plant density 2 plants/m
soil cover >80 mm deep.
only for areas with soil cover >80 mm Native vascular plant cover, density or
depth.
height same or less than in previous
0 to 40% rock/boulder cover.
monitoring.
Visible gorse, broom, Juncus
squarrosus.
The criteria will be measured in randomly located plots stratified by landform and may be stratified
by age to allow progressive closure/bond reduction.
Minimum plot sizes have not been finalised and are likely to differ with vegetation and landform.
BD = basal diameter.
Intervention triggers for weeds are based on the accepted basal cover of 10%,
recognising that at soon as the species is observed control will be initiated. The <10%
cover target will be confirmed based on the outcomes of trials and as longer-term results
become available.
8.
RESPONSIBILITIES AND REPORTING
The resource consents require that the responsibilities of personnel on site and a training
schedule be provided to ensure the rehabilitation is achieved to the required standard
(conditions XX). Specific responsibilities are divided between the Environmental
Supervisor and Senior Mining Engineer – Environmental as outlined below.
Rehabilitation measures are to be integrated into the routine mining operations. The
employment of an Environmental Supervisor with ultimate responsibility for sign off at
various stages of the rehabilitation and responsibility for coordination of activities, supply
of vegetation, control of weeds and pests, staff training, reporting and fire protection is
an important part of the rehabilitation strategy. The insertion of specific clauses into
stripping contracts to encourage and enforce the maximum salvage of intact vegetation
and soils, minimise the area disturbed and respect the mine footprint boundary is also a
key component to achieving the required standards.
Condition X requires an Annual Environmental Monitoring Report to be provided to the
West Coast Regional Council, Peer Review Panel/Technical Advisory Group [TBC] and
Department of Conservation one month prior to the anniversary of commencement of
activities, which includes data up to two months prior to the anniversary. This is the
responsibility of the Environmental Supervisor. Any monitoring that is required to be
undertaken concerning rehabilitation will be provided in that report.
Environmental induction will include specific training to ensure that operators are familiar
with the procedures and their importance in their relevant area of operations. A Training
Manual will summarise the induction information and will be available to all staff.
The Senior Mining Engineer (Environmental) is responsible for ensuring standards are
met by external contractors and coordinating activities with the environmental supervisor
to ensure progress is timely and of a high standard.
The Rehabilitation Peer Reviewer is responsible for reviewing the annual monitoring
report and annual work plans and assessing the progress of the rehabilitation and
providing verbal and written feedback to Te Kuha Limited Partnership.
The Environmental Supervisor must:

Sign off each stripping block plan before stripping begins. Stripping is defined
as any felling of vegetation by either hand or machine.

Sign off each exploration drilling plan before drilling proceeds.

Sign off each rehabilitation block once rehabilitation has been carried out.

Coordinate with mine engineer regarding timing of stripping and landform
release for rehabilitation.

Ensure access is available to enable plant salvage pre-stripping (so that small
vehicles can enter source areas) and that access remains available for post
rehabilitation monitoring. Felling may be before or after plant salvage, which
means that stripping may have partially begun.

Ensure vegetation supply contracts include quality (i.e. height, bushiness,
vigour, etc.) and weed hygiene provisions and penalties.

Ensure vegetation supply contracts uphold condition X – “Seed and plant
resources shall be genetically sourced from the locality or Ngakawau
Ecological District from at least 500 m above sea level.”

Ensure that weed spraying or other removal is carried out on a regular basis
along the mine road and disturbed areas, and ensure that target weed colonies
away from the roads are monitored and controlled by spraying or other
methods.

Monitor the effectiveness of weed control. This will require knowledge on
where ‘weed control’ has been attempted and for which species.

Ensure that any machinery utilised for any rehabilitation activities, including
excavation of topsoil, which is brought onto or moved from the site is cleaned
before and after use in order to minimise the potential for weed species to be
introduced onto or off the site.

Ensure that any materials, i.e. gravels, overburden, sheeting, etc. used on site
are not from weed-infested areas.

Monitor the effect of animal pest species on the revegetation areas and on
natural areas and instigate control measures as necessary.

Ensure that all staff using sprays have been properly trained (e.g., “Growsafe”)
and are familiar with the NZ Standard Code of Practice for the Management
of Agrichemicals NZS 8409:1999.

Provide an Annual Environmental Monitoring Report on Rehabilitation (as set
out in condition X) to the Consent Authority and Peer Review Panel/TAG at
least five working days before the site visit (and at least one month prior to
each anniversary of the commencement of these consents). The monitoring
period to be included in each report shall be for the 12-month period ending
two months prior to the anniversary of the commencement of these consents.
A copy shall also be provided to the Department of Conservation.

Ensure that the performance of any modified landform, watercourse, or any
permanent structures and facilities under a Probable Maximum Flood or
Maximum Credible Earthquake do not result in damage to landforms or
structure greater than those that would have occurred under natural slope and
landform conditions (XX).

Revise fire protection standards (Condition X).

Ensure a “Rehabilitation Training Schedule” for staff and contractors is
developed and implemented (condition X). This will have specific modules for
different contractors, e.g., the direct transfer crew.

Investigate the best location for the wheel wash and ensure it is in place prior
to light vehicles commencing access to the site.

Ensure that vehicles accessing the area (including heavy vehicles that have
been through weedy areas and light vehicles from outside the area) travel
through the vehicle wash provided to minimise weed transfer.

Ensure that prior to entering the Te Kuha area, all staff clean their footwear,
removing all visible foreign debris and immersing footwear in disinfectant, to
prevent weed seed being tracked onto the site.

Maintain a register of weed inspections for the site so that all areas are
regularly and systematically inspected. An example of a weed register is given
in Appendix 3.

Update the weed list based on weed incursions at Te Kuha, on the West Coast
Regional Council Pest Plant Strategy and advice from the Department of
Conservation, West Coast.

Ensure any hydroseeding or mulching machines are clear of foreign species
prior to use at Te Kuha.

Report annually on the weed control undertaken and extent of weeds at the
site, including identifying any problem species or locations for future action.
The Senior Mining Engineer – Environmental must:

Ensure that the soil and vegetation stripping, stockpiling and spreading
contracts include quality provisions and penalties.

Ensure that the Contractor and all staff are properly trained to undertake any
rehabilitation–related tasks to the appropriate standard, and shall carry out
and record fortnightly audits to ensure the standards set out in the stripping
contracts are maintained.

Coordinate with environmental supervisor to ensure that adequate areas are
available for stripped material to be placed, soil to be stockpiled, adequate
areas are ready for planting to keep abreast of seedlings ordered or plants
salvaged.

Ensure access to the final landform for each rehabilitation block prior to final
surfacing with topsoil and rehabilitation resources and sign off as required.

Ensure that the final landform, watercourse, or any permanent structures and
facilities under a Probable Maximum Flood or Maximum Credible Earthquake
do not result in damage to landforms or structure greater than those that would
have occurred under natural slope and landform conditions.

Ensure that rehabilitation resources are made available when needed, for
example, specific rock sizes and types for lining stream diversions.

Ensure that all staff and contractors remain trained as per the “Rehabilitation
Training Schedule”.

Prior to revegetation the site engineer must check total rooting depths are
adequate before signing off individual blocks for spreading of topsoil and plant
establishment.
Topsoil depth and quality must be assessed before
revegetation treatments are done, because increasing topsoil depth is
impractical once seedlings have been planted, and the revegetation details
are influenced by the density of regenerating plants in spread topsoil.
All staff must:

Be vigilant about transferring potential weeds on vehicles, machinery and
boots.

Record locations of weed species, preferably using a GPS, and alert the
Environmental supervisor as soon as practicable.

Remove and report weed species when seen in the field.
8.1
Rehabilitation Training Schedule
The Environmental Supervisor will have responsibility to ensure a “Rehabilitation
Training Schedule” for staff and contractors is developed and implemented and the
Senior Mining Engineer will have responsibility to ensure that the skills of the staff and
contractors are maintained.
The Rehabilitation Training Schedule must provide training for:

Stripping, stockpiling, spreading and contouring of rehabilitation materials to
an appropriate standard.

Implementation of direct transfer and care of stored direct transfer material.

Rehabilitation tasks to be performed to an appropriate standard.

Maintaining access for monitoring.

Ensuring that the correct landform (as designed) and landform stability are
achieved.

Identification of weeds and pests, monitoring and control methods (e.g., NZ
Standard Code of Practice for the Management of Agrichemicals NZS
8409:1999).

Cleaning of machinery and vehicles to an appropriate standard.

Sourcing appropriate seed and plant resources from the locality or the
Ngakawau Ecological District above 500 m asl (as per condition X).

Fire protection for revegetated sites.
9.
REFERENCES
Mitchell Partnerships Ltd 2013. Vegetation and Fauna of the Proposed Te Kuha Mine
Site. Unpublished report prepared for Te Kuha Limited Partnership. Mitchell
Partnerships Ltd. Takapuna, Auckland. October 2013. 113 pp + appendices.
National Possum Control Agency (NPCA) July 2008. Possum population monitoring
using the trap – catch method. NPCA, P.O. Box 11 461, Wellington.
www,npca.org.nz
Theinhardt, N. I. 2003: Plant restoration at an open cast coal mine West Coast, New
Zealand. Unpublished MSc Thesis, University of Canterbury, Christchurch,
New Zealand.
APPENDICES
APPENDIX 1
Resource Consent Conditions
APPENDIX 2
Species proposed for use in rehabilitation
APPENDIX 3
Sample Weed Register
APPENDIX 4
Five Minute Bird Count Method