April 20, 2016
Toro Energy Ltd
Level 3, 33 Richardson Street
West Perth, Western Australia
6005
Wiluna Extension Uranium Project: MWH responses to PER comments
re: subterranean fauna
Attention:
Richard Yeeles
Approvals and Community Director
Dear Richard
As discussed, the purpose of this letter is to provide a response to the Wiluna Extension Uranium Project
PER comments regarding subterranean fauna received from the Australian Government Department of the
Environment (DotE), the Western Australian Government Department of Parks and Wildlife (DPAW), and
the combined submission from the Conservation Council of Western Australia, the Australian Conservation
Foundation, Friends of the Earth Australia, The Wilderness Society, the Anti Nuclear Alliance of WA and the
West Australia Nuclear Free Alliance.
Yours sincerely
Nicholas Stevens
MWH Australia Pty Ltd
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1
Australian Government Department of the Environment (DotE)
The DotE Per comments related to subterranean fauna that MWH has provided a response to are
presented in full in Appendix A.1.
1.1
Maintenance of subterranean fauna habitat values (pp. 10 — 11)
Provision of further justification and evidence to support the statement regarding the susceptibility of
subterranean fauna to changes in groundwater levels made in Section 12.6.2 of PER (p.12-27): “…
subterranean fauna habitat values can be maintained by limiting groundwater drawdown to an amount
that is not significantly different to the naturally occurring year to year variability in water levels or by
maintaining thickness of aquifer at approximately 70% of pre-mining thickness, ensuring habitable
geologies remain saturated.”
The 2015 PER statement relates to two criteria previously established and accepted for the 2012 PER
assessment of the Wiluna Project: 1) delineation of the extent of the groundwater drawdown impacts;
and 2) maximum drawdown permissible to ameliorate groundwater abstraction impacts associated with
the West Creek borefield.
The criterion used in the approved 2012 PER assessment for the delineation of the minimum
groundwater drawdown limit (drawdown impact boundary) to be considered to represent a direct impact
as a result of borefield abstraction or mine pit dewatering was 0.5 m below the natural standing water
level (m bSWL). The proposed drawdown contour of 0.5 m bSWL was designated as the outer extent of
drawdown impact because groundwater drawdowns of less than 0.5 m bSWL fall within the natural
variation in standing water levels recorded from Project areas, with fluctuations commonly ranging from
± 0.1 to 0.3 m bSWL, with less common variations occurring in the range of ± 0.6 to 1.26 m bSWL
(Outback Ecology 2011, 2012a, b). Additional monitoring of groundwater levels by Toro also confirmed
the solid rationale in establishing a drawdown of 0.5 m bSWL as the outer extent of drawdown impact
with natural fluctuations of standing water levels generally ranging from ± 0.44 to 1.22 m bSWL
(Appendix B).
Groundwater drawdowns that exceed the natural variation as a result of human activities are considered
to directly impact on stygofauna by reducing the vertical extent of habitat available (EPA 2007). The
designated 0.5 m bSWL does not exceed the natural variation measured within the calcrete habitats
associated with both Lake Way and Lake Maitland. Therefore, vertical drawdowns that are less than
0.5 m bSWL are considered to not be significantly different to the natural year to year variability in
standing water levels, thereby maintaining stygofauna fauna habitat values beyond the designated
0.5 m bSWL drawdown contour.
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Troglofauna are considered to represent relictual fauna related to surface dwelling (epigean) groups that
have evolved to be obligate inhabitants of subterranean environments that provide more constant and
humid refugia (Humphreys 2000). The potential reliance of troglofauna on stable and relatively high humid
conditions could make them susceptible to artificially changing water tables, particularly if the lowering of
the water table is of a sufficient magnitude to dry out the inhabited zone that could have significant impacts
on any troglofauna species present (EPA 2007). The impacts of groundwater drawdown on humidity levels,
and the subsequent potential impacts on troglofauna have not been studied.
However, groundwater
drawdowns are considered to have greater impacts on stygofauna because the extent of habitat available is
directly reduced. For troglofauna, the lowering of the groundwater table could result in a portion of the
saturated habitat present, known to host stygofauna species, becoming unsaturated and available for
colonisation by troglofauna. Diverse troglofauna assemblages have been recorded from shallow deployed
litter traps from numerous iron ore rich mesas and ranges in the Pilbara where the standing groundwater
levels can often be more than 50 m below ground level (m bgl), sometimes exceeding 100 m bgl (Biota
2006, Humphreys et al. 2006, MWH 2014a, b, Subterranean Ecology 2008). The modelled groundwater
drawdowns of less than 0.5m bSWL that do not exceed natural variations are not considered to be of a
large enough magnitude to lower the relative humidity to such a degree as to render the subterranean
environments uninhabitable by members of the troglofauna assemblage recorded.
The justification for limiting groundwater drawdown to maintain the thickness (depth) of the calcrete
aquifer at the monitored borefield abstraction point/s to approximately 70% or greater of pre-mining
thickness was based on data from eastern Goldfield calcrete aquifers.
Groundwater abstraction
investigations had indicated that standing water levels (SWL) would begin to drop more rapidly, along
with diminishing bore yields, once drawdown levels fell below 66% of the saturated thickness of the
calcrete aquifer (Resource Investigations (1991) in Aquaterra (2010)).
The compliance stygofauna monitoring program, established for the operation of the Magellan Metals
production borefield in response to imposed Ministerial conditions , set what was considered a
conservative aquifer drawdown limit of 75% to preserve calcrete stygofauna habitat (Biota 2005). The
monitoring of groundwater levels and stygofauna diversity from 2006 to 2012 indicated that the
abstraction of groundwater within the imposed limits did not result in any evidence of significant change
or deterioration in the stygofauna assemblage in impact areas (Bennelongia 2012, Outback Ecology
2008, 2010).
Further evidence of the robustness of stygofauna assemblages surviving calcrete aquifer drawdowns is
provided by the Ethel Gorge stygofauna assemblage that persisted over the period that the groundwater
level, as a result of neighbouring mining activity, declined below the calcrete habitat present, and
subsequently recovered when groundwater was restored to more natural levels .
The Lake Violet
calcrete assemblage has also displayed resilience to groundwater abstraction associated with the
operations of the West Creek borefield from 1987 to 1994 and the Apex (Wiluna Gold Mine) Southern
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Borefield from 1987 to 1991, and 2005 to 2007. The Apex Southern Borefield was also in operation
during the stygofauna survey periods of late 2011 and early 2012. The documented abstraction rates
for the West Creek borefield were around 0.43 GL/year (Aquaterra 2010).
For the Apex Southern
Borefield, abstractions rates ranged from 0.16 to 0.57 GL/year from 1987 to 1991 and 0.74 to
0.79 GL/year from 2005 to 2007 (Aquaterra 2010).
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2
Western Australian Government Department of Parks and Wildlife (DPAW)
The DPAW PER comments related to subterranean fauna that MWH has provided a response to are
presented in full in Appendix A.2.
2.1
Item 4 — Recommendation 2: Provision of more thorough and comprehensive predictions
of impacts on stygofauna PECs (pp. 9).
Recommendation 2: That the proponent is requested to provide more thorough and comprehensive
predictions of the direct, indirect and cumulative impacts on subterranean PECs and associated taxa for
a consolidated assessment.
The Extension to the Wiluna Uranium Project PER and supporting subterranean fauna technical reports
are considered to have provided a thorough, reliable and comprehensive assessment of the proposed
direct, indirect and cumulative impacts on the subterranean fauna assemblages associated with the
Hinkler Well and Barwidgee calcrete systems, including the Hinkler Well and Barwidgee calcrete
stygofauna Priority Ecological Communities (PECs), posed by the development of the Millipede and
Lake Maitland mining areas. However, to ensure concerns raised regarding the stygofauna PECs are
adequately addressed, the related salient findings and environmental impact assessments presented
previously are discussed in further depth below.
Direct Impacts (mining excavation and groundwater drawdown)
The direct impacts posed by the development of the Millipede and Lake Maitland mining areas on
stygofauna include the removal of habitat through the excavation of the proposed mining pits, and drying
out of habitat through the lowering of the groundwater table associated with mine pit dewatering. The
removal of habitat through mining excavation poses the greater level of risk to the conservation of
stygofauna species relative to the lowering of the groundwater table only. This is because stygofauna
species have been demonstrated to be able to tolerate reasonable fluctuations in standing groundwater and
persist as a species in areas that have been subjected to groundwater (refer discussion in Section 1 and
references therein). The minimum groundwater drawdown considered to represent a direct impact was
0.5 m bSWL for reasons further discussed above in Section 1.
In the PER (Toro Energy Limited 2015) and supporting technical reports provided (MWH 2015, Outback
Ecology 2012a, b), the lateral extent of both direct impacts were presented, including in relation to the
distributions of the stygofauna diversity recorded that comprise the Hinkler Well and Barwidgee calcrete
stygofauna PECs.
The figures presented in MWH (2015) in relation to the recorded stygofauna
distributions associated with the Hinkler Well calcrete are provided again in Appendix C. The proposed
and approved Centipede mine pit boundary (directly adjacent to the Millipede mine pit) was also included in
the assessment of the Millipede extension so the cumulative direct impacts of the combined Centipede and
Millipede mine pits could be assessed. The figures presented in Outback Ecology (2012a) of the recorded
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stygofauna distributions associated with the Barwidgee calcrete have been modified to present findings
more clearly in relation to modified proposed Project impacts and are provided in Appendix D.
In relation to the Hinkler Well calcrete stygofauna assemblage, three species (Amphipoda: Chiltoniidae sp.
SAM6; Bathynellacea: Brevisomabathynella sp. SAM2; and Copepoda: Schizopera sp. TK4) that have not
been recorded from outside the proposed Millipede and Centipede mining excavation areas, and a further
two species (Schizopera TK7 and TK10) that have not been recorded from beyond the modelled 0.5 m pit
dewatering groundwater drawdown contour (Appendix C: Table C-1). To date Chiltoniidae sp. SAM6 has
only been found from within the proposed Millipede pit ((Appendix C: Figure C-1).
Both
Brevisomabathynella sp. SAM2; and Schizopera sp. TK4 have only been recorded from within the proposed
Centipede pit ((Appendix C: Figures C-2 and C-5) and were previously assessed in the 2011 Wiluna
Project PER (Toro Energy Limited July 2011).
In relation to the Barwidgee calcrete stygofauna assemblage, there were two species (Chiltoniidae sp.
SAM4 and Schizopera sp. TK1) that have not been recorded from outside the proposed Lake Maitland
mining excavation areas (Appendix D: Table D-1, Figures D1 and D3). Previously, only one species
(Isopoda: Haloniscus sp. OES1) had not been recorded from beyond the modelled 0.5 m pit dewatering
groundwater drawdown contour (Outback Ecology 2012a). However, the modified mine plan that proposes
a decrease in mining excavation volume and associated dewatering demands has resulting in a less
extensive modelled 0.5 m groundwater drawdown contour. Therefore, records of Haloniscus sp. OES1 now
occur from outside the modelled 0.5 m pit dewatering groundwater drawdown contour in the non-impact
area, so is no longer of conservation concern (Appendix D: Figure D-7).
In each of the EIA technical reports concerning the Hinkler Well and Barwidgee calcrete stygofauna
assemblages, the predictions were that the direct impacts would not be considered likely to pose a long
term conservation risk to the stygofauna species found to be restricted to direct impact areas only (MWH
2015, Outback Ecology 2012a, b). In each case, the main reasons for deriving these predictions from the
assembled data were related to the likelihood that each of the species of conservation concern would
possess a broader distribution than had been recorded. The sound basis for arriving at such a likelihood
took into account information regarding:

broader distributions and/or habitat preferences of other closely related species, including from
other studies from other geographic locations;

the broader distribution patterns and habitat preferences of other members of the stygofauna
assemblage, including members collected sympatrically; and

the broader distributions and habitat preferences recorded in different studies from other
geographic locations within other stygofauna assemblages.
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
extent of proposed habitat removal associated with mining excavation, relative to the much greater
expanse of adjacent habitat remaining.
DPAW, under “Issue 3:
Insufficient information presented to support inferred broader distributions of
subterranean fauna taxa”, has considered these predictions to be “unreliable and insufficiently robust”
because they believe that conclusions presented in the PER “appear to rely on the distributions of other
taxa and uniformity and connectivity throughout calcrete systems” and “are not supported by survey data or
other habitat related information”. However, it appears from the comments provided under Issue 3 that the
technical reports were not consulted, but only the PER summation of the supporting technical information.
In each of the technical reports appended to the 2015 PER, extensive habitat related information was
presented: Section 4.1.1 Stygofauna habitat (Outback Ecology 2012a); Section 3.1 Subterranean habitat
(MWH 2015); Section 4.1.1 Stygofauna habitat (Outback Ecology 2012b). This information was compiled
from all available geological and hydrogeological information, including known bore lithothologies as well as
groundwater quality survey data.
The information indicated that habitat would remain outside of the
proposed mining areas as well as within the modelled 0.5 m bSWL groundwater drawdown contour.
Assessing stygofauna diversity and species distributions is difficult as sampling the full extent of their likely
range is not possible as access to the subterranean habitat is constrained by the lack of bores and caves
available.
In addition, there are temporal variations in assemblage diversity when sampling as
demonstrated with the continuation of the discovery of new species from previously relatively well sample
areas (Guzik et al. 2010) or species only recorded intermittently over the course of an extensive survey
program (Karanovic and Cooper 2012, MWH 2015). It is for such reasons that the use of physical and
biological surrogates have been recommended as a means to infer potential distributions of subterranean
species, particularly for species that are known to exist from limited records only (Environmental Protection
Authority 2013).
Molecular studies of subterranean species have demonstrated that the use of physical and biological
surrogates is a valid approach to assessing the potential distribution of a species known from a single
specimen or bore location.
Investigations of population structure of stygofauna species in the Sturt
Meadows and Laverton Downs calcrete systems indicated that similar trends in distribution patterns at the
species and population levels existed amongst sympatric species of the same order as well as of different
orders, with linear ranges in the Laverton Downs calcrete shown to extend for as great as 15 km for
amphipod, beetle and isopod species (Bradford et al. 2013, Guzik et al. 2011). Of particular interest from
these and other stygofauna molecular studies is that the majority of stygofauna species studied within a
calcrete system have been shown to have evolved from independent colonisation by epigean (surface)
ancestors and not from allopatric speciation of a stygofauna ancestor; i.e. the populations of a species
within a calcrete system have not become isolated from each other such that gene flow has ceased to an
extent that populations have diverged into separate species (Cooper et al. 2007, Cooper et al. 2002,
Cooper et al. 2008, Guzik et al. 2008, Guzik et al. 2011, Karanovic and Cooper 2011, Karanovic and
Cooper 2012, Leijs et al. 2003). Instead, the haplotype diversity found to be present did indicate that the
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aquifer environment has been relatively dynamic with many fluctuations in groundwater levels and resource
recharge over the past few million years with water table levels likely to have been much lower during
glacial periods than they are at present (Guzik et al. 2011).
Information regarding either physical habitat or biological characteristics of a subterranean fauna
assemblage can inform and support one another. Genetic studies have indicated that hydrogeological
isolated calcrete systems can represent closed ‘subterranean islands’ in terms of the species of the
stygofauna assemblage present are restricted in distribution to a particular calcrete only (Cooper et al.
2002, Cooper et al. 2008, Guzik et al. 2008). The Lake Way calcrete systems have been shown to be
unique in that genetic data has indicated that for some taxa gene flow does occur among the close
neighbouring calcrete systems, particularly among the northern lake associated calcretes, Lake Violet and
Uramurdah, and with Millbillillie Bubble Well calcrete.
The genetic data was consistent with the
hydrogeological assessment. The notion was supported by genetic results reported in Abrams et al. (2012)
and Outback Ecology (2011, 2012b), that demonstrated the distribution of amphipod, Bathynellacea and
dytiscid species to extend from Millbillillie Bubble Well calcrete to Lake Violet and Uramurdah calcretes. In
addition, molecular data has shown that Atopobathynella wattsi has a distribution extending from the Lake
Violet calcrete to the Hinkler Well calcrete (Guzik et al. 2008).
However, there are instances where
hydrogeological data may be inconsistent with the biological data.
An example was the molecular
investigation of the Browns Range stygofauna assemblage that demonstrated that there was a physical
connection between two hydrogeologically distinct aquifers that were considered isolated from one another,
with two bathynellicean species clearly shown to occur in both (Outback Ecology 2014).
The Millipede targetted survey provided additional support to the validity of using physical and biological
surrogates to infer likely distributions of stygofauna species. Firstly, the range expansion demonstrated for
Schizopera sp. TK7 that had previously been found from within the Centipede deposit area only but whose
wider distribution was initially hypothesised using physical and biological surrogates (MWH 2015).
Secondly, intra-specific (within species) genetic variation displayed between the two specimens of
Chiltoniidae-SAM6 sequenced was 1.2% which was marginally greater than that displayed for the more
commonly collected Chiltoniidae-SAM3 with 1.1%.
The co-occurrence of a higher level of haplotype
diversity among specimens collected within a limited geographical area can be an indication of a relatively
large and more widespread population than location records may show (Guzik et al. 2011), which would be
consistent with the broader extent of habitat present as well as the wider distribution of closely related
amphipod species present in the Hinkler calcrete (Outback Ecology 2012b; MWH 2015).
The PEC boundaries depicted do reflect a recent refinement of the mapping of the lateral extent of the
calcrete aquifers and likely did take into account the new scientific information that was provided from the
stygofauna investigations that were undertaken as part of the 2012 PER. The mapped boundaries of the
PECs do reflect the extent of calcrete habitat, including submerged and surface expressed calcrete. The
extent of calcrete shown in the maps provided in the subterranean fauna assessments (Outback Ecology
2012a, b; MWH 2015) was of surface expressed calcrete, and did not include the submerged extent of the
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calcrete systems. Therefore, the reworking by DPAW, under “Issue 1: The PEC boundaries are indicative”
of the percentage of the calcrete that may be directly impacted by the proposed Project would overrepresent the proportion of potential habitat impacted.
An important point to make regarding the groundwater drawdown that MWH concedes was not clearly
made in the subterranean fauna EIA’s is that the modelled 0.5 m bSWL contour represents the combined
lateral extent of the individual drawdowns associated with each mining panel as they are successively
excavated; i.e. the area within the modelled 0.5 m bSWL groundwater drawdown contour will experience a
drawdown as a result of successive dewatering of each mine panel, however, the drawdown will not occur
simultaneously to the extent of the modelled 0.5 m bSWL drawdown contour.
The proposed mining
schedule will mean that the modelled 0.5 m bSWL groundwater contour associated with each mining panel
as they are successively excavated will represent a subset of the depicted maximal extent of groundwater
drawdown impact.
Indirect Impacts
Issue 1. Estimates of indirect impacts do not appear to take into account changes to natural physicochemical gradients in aquifers supporting the subterranean fauna PECs.
The proposed mine dewatering at both Millipede/Centipede and Lake Maitland is not considered to
result in significant disruptions to the natural physico-chemical gradients in the broader calcrete aquifers
supporting the stygofauna PECs because the groundwater inflow into each of the excavated mine
panels would predominantly be horizontal flow from the upper several metres of t he neighbouring
aquifer (RPS 2015). The upper groundwater surrounding the proposed mining panels consists of mostl y
hypersaline waters. Potential disruptions to the natural physico-chemical gradients would be considered
to only occur close to where mine pit dewatering and excavation would be occurring. Therefore, the
extent of this potential indirect impact would not be considered to extend far beyond the proposed mine
pit boundary. As a result of this the EIAs presented in the technical reports have considered species
close to mine pit boundaries so have addressed this perceived indirect impact Outback Ecology 2012a;
MWH 2015).
Cumulative Impacts
The PER appended technical report, Outback Ecology (2012b) did provide a table ( Table 6) that listed
all stygofauna species and for species found in other calcrete systems it was indicated if they occurred
outside the proposed Project areas (Appendix E: Table E-1). In addition, Table 5 of the Lake Maitland
stygofauna PER appended technical report (Outback Ecology 2012a) indicated which species had been
recorded from other calcrete systems (Appendix D: Table D-1). In both technical reports, all species
known from additional calcrete systems have been recorded from locations outside of the proposed
Project impact areas.
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3
Conservation Council of Western Australia, the Australian Conservation
Foundation, Friends of the Earth Australia, The Wilderness Society, the Anti
Nuclear Alliance of WA and the West Australia Nuclear Free Alliance
(CCWA)
The CCWA PER comments related to subterranean fauna that MWH has provided a response to are
presented in full in Appendix A.3.
3.1
Recommendation that further studies be conducted to provide evidence on the habitat
range of restricted stygofauna (pp. 10 — 13)
We recommend further studies are conducted to provide evidence on the habitat range of the following
species that are currently only found in the impact area of mining and dewatering:

Centipede: Schizopera sp. TK10

Millipede: amphipod Chiltoniidae-SAM6, Schizopera sp. TK10 (Copepoda) Brevisomabathynella sp.
SAM2 (Bathynellacea); Schizopera sp. TK4 (Copepoda); and Schizopera sp. TK7 (C opepoda)

Lake Way: Paramelitidae sp. SAM2 (Amphipoda); Brevisomabathynella sp. OES6 (Bathynellacea);
and Parapseudoleptomesochra sp. ?TK2 (Copepoda).”

West
Creek
Bore:
Chiltoniidae
sp.
SAM2
(Amphipoda);
Brevisomabathynella
sp.
SAM3
(Bathynellacea); Brevisomabathynella sp. SAM4 (Bathynellacea); Parabathynellidae sp. OES13
(Bathynellacea); and Parapseudoleptomesochra sp. TK2 (Copepoda).

Lake Maitland: Haloniscus sp. OES1; Chiltoniidae sp. SAM4 and Schizopera sp. TK1.
MWH does not consider further studies are required to provide additional evidence of the habitat range
of the stygofauna species recorded from both the Hinkler Well and Barwidgee calcrete systems within
proposed impact areas only. The stygofauna species recorded from the Lake Way and West Creek
Project areas have been previously assessed and are not considered further here. The subterranean
fauna technical reports (Outback Ecology 2012a, b; MWH 2015) are considered to have provided a
thorough, reliable and comprehensive assessment of the propose d direct, indirect and cumulative
impacts on the subterranean fauna assemblages associated with the Hinkler Well and Barwidgee
calcrete systems, including the Hinkler Well and Barwidgee calcrete stygofauna Priority Ecological
Communities (PECs), posed by the development of the Millipede and Lake Maitland mining areas.
Further discussion regarding the evidence for broader distributions of stygofauna known from limited
records is presented above in Section 2.
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4
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in the Kinnecaris solitaria complex (Copepoda: Parastenocarididae), with descriptions of seven new
species. Zootaxa 3026: 1-64.
Karanovic, T. and Cooper, S. J. B. (2012) Explosive radiation of the genus Schizopera on a small
subterranean island in Western Australia (Copepoda: Harpacticoida): unravelling the cases of
cryptic speciation, size differentiation and multiple invasions. Invertebrate Systematics 26: 115-192.
Leijs, R., Watts, C. H. S., Cooper, S. J. B. and Humphreys, W. F. (2003) Evolution of subterranean diving
beetles (Coleoptera: Dytiscidae: Hydroporini, Bidessini) in the arid zone of Australia. Evolution
57(12): 2819-2834.
MWH. (2014a) Troglofauna Annual Compliance Monitoring: Mesa K 2013 Prepared for Rio Tinto Iron Ore,
Perth, Western Australia.
Status: Draft Response
Project No.: 83502571
20160408
Page 11 Our ref: MWH Response DotE DPAW CCWA PER Submissions re Sub Fauna V1-3
MWH. (2014b) Troglofauna Annual Compliance: Mesa A and Mesa B 2014 Prepared for Rio Tinto Iron
Ore, Perth, Western Australia.
MWH. (2015) Wiluna Uranium Project: Millipede Targeted Subterranean Fauna Assessment Report
prepared for Toro Energy Ltd.
Outback Ecology. (2008) Stygofauna assessment for the Magellan Lead Project - Wiluna 2008 Report
prepared for Magellan Metals Pty Ltd, Perth, Western Australia.
Outback Ecology. (2010) Magellan Lead Project, 2010 Stygofauna Compliance Monitoring Prepared for
Magellan Metals Pty Ltd.
Outback Ecology. (2011) Wiluna Uranium Project Subterranean Fauna Assessment, March 2011.
Prepared for Toro Energy Ltd, Perth, Western Australia.
Outback Ecology. (2012a) Lake Maitland Uranium Project Level 2 Stygofauna Assessment Prepared for
Mega Lake Maitland Pty Ltd, Perth, Western Australia.
Outback Ecology. (2012b) Wiluna Uranium Project Stygofauna Assessment Prepared for Toro Energy Ltd,
Perth, Western Australia.
Outback Ecology. (2014) Browns Range Project Subterranean Fauna Assessment Report prepared for
Northern Minerals Ltd, Perth, Western Australia.
Resource Investigations. (1991) Report on groundwater Production and Water Level Monitoring – 30/4/89
to 16/1/19, Matilda Gold Project, Wiluna, WA – Groundwater Well Licence Numbers 32065, 32069,
32080 and 32082, Report prepared for Eon Metal NL.
RPS. (2015) CENTIPEDE - MILLIPEDE GROUNDWATER IMPACT ASSESSMENT Report prepared for
Toro Energy Ltd.
Subterranean Ecology. (2008) Goldsworthy Iron ore Mining Operations Cundaline and Callawa mining
Operations Troglofauna Assessment Report prepared for BHPBIO.
Toro Energy Limited. (2015) Extension to the Wiluna Uranium Project. Assessment No: 2002 (CMS14025)
Public Environmental Review. November 2015.
Toro Energy Limited. (July 2011) Wiluna Uranium Project. Environmental Review and Management
Programme (ERMP). EPA Assessment No 1819, Perth, Western Australia.
Status: Draft
Project No.: 83502571
20160408
Page 12 Our ref: MWH Response DotE DPAW CCWA PER Submissions re Sub Fauna V1-3
Appendix A
Wiluna Extension Uranium Project PER
Comments
A.1
Australian Government Department of the Environment (DotE) PER comments
Table 0-1: Wiluna Extension Uranium Project DotE PER comments received from Toro Energy on February 10, 2016.
PER section
Issue
Information required
Essential at this stage?
12.6.2 –
groundwater
drawdowns
Further discussion and
analysis should be
considered in the PER.
‘In Western Australia, it has generally been assumed that
subterranean fauna habitat values can be maintained by
limiting groundwater drawdown to an amount that is not
significantly different to the naturally occurring year-toyear variability in water levels or by maintaining the
saturated thickness of the aquifer at approximately 70%
of the pre-mining saturated thickness, ensuring habitable
geologies remain saturated. Toro has used a nominal 0.5
m groundwater drawdown level as the indicator of the
minimum amount of change likely to result in discernible
impacts on subterranean fauna habitats…’. Provide
further justification and evidence to support the above
claim regarding the susceptibility of subterranean fauna
to changes in groundwater.
Essential – in addition to evaluating
the application of the 0.5 m
drawdown limit (Comment 9.5.4
above) – on-going monitoring of
ecosystem health resulting from the
GW drawdown and reductions in
saturated extent of the aquifer
should also be assessed and
adaptively managed.
12.6.2
Groundwater
Drawdown
(p12-33)
A further possible source of
indirect impact to
subterranean fauna habitats
is the proposed reinjection of
surplus mine water at Lake
Maitland. In order to meet its
commitment not to discharge
surplus water to the Lake
Maitland playa, Toro has
investigated the feasibility of
returning groundwater
intercepted by mining to the
aquifer from which it was
abstracted.
The PER should include some investigation and
discussion of alternative reinjection sites to maintain
stygofauna habitat.
Moderate priority – affects ability to
assess potential impact.
& Appendix
10.30
A.2
Western Australian Government Department of Parks and Wildlife (DPAW) PER comments
Table A-2: Wiluna Extension Uranium Project PER comments received from DPAW, dated February 8, 2016.
SUBTERRANEAN FAUNA
Subterranean
fauna
Comment: The proposal will impact on the Priority 1 PECs 'Hinkler Well calcrete groundwater assemblage type on
Carey palaeodrainage on Lake Way Station' and 'Barwidgee calcrete groundwater assemblage type on Carey
palaeodrainage on Barwidgee Station'. This adds to impacts associated with the original approval proposal which,
in addition to impacting the Hinkler Well calcrete community, will also impact on 'Lake Violet south and Lake Violet
calcrete groundwater assemblage types on Carey palaeodrainage on Millbillillie Station' and 'Uramurdah Lake
calcrete groundwater assemblage type on Carey palaeodrainage on Millbillillie Station'.
The PEC listings are based on the identified presence of unique assemblages of invertebrates with potentially
restricted distributions centred on calcretes. The main identified potential threat to the high biodiversity values of
these communities is approved mining (including changes to hydrology), with environmental impact assessment
and approvals processes providing a mechanism to consider and address or mitigate these threats, where
appropriate.
4
The calcrete bodies of the Yilgarn are considered to have particularly rich subterranean fauna communities, with
taxa often restricted to single calcretes. This pattern of species distribution has lead to scientific investigators
working in this area developing what is known as the calcrete islands theory. The information presented in the PER
supports the theory to a significant degree, with a number of stygofauna and troglofa una apparently restricted to a
single calcrete and adjacent surrounding area containing suitable habitat.
Whilst it is unlikely that sampling at Hinkler Well and Barwidgee calcretes has identified all species that occur within
these PECs, a high proportion of subterranean species collected are only known from the individual PECs. At the
Hinkler Well PEC, 15 of the 34 stygofauna and 8 of the 9 troglofauna species have records restricted to this PEC
(Tables 12-6 and 12-7). At the Barwidgee PEC, 21 of the 28 stygofauna have records restricted to this PEC (Table
12-9). Distribution data are not provided in the PER for troglofauna at Barwidgee (Table 12 -10) to assess the
number of troglofauna only known from the Barwidgee PEC.
Item
No.
Section
No./Title
Reviewer Comment I Advice
Although calcrete aquifers are characterised by complex physico-chemical gradients, including abrupt haloclines,
the tolerance limits or habitat requirements and distributions of species and communities are not known. The highly
restricted distributions of many subterranean fauna species makes these communities particularly vulnerable to
disturbance and the capacity of these species and communities to reestablish in disturbed or degraded habitat is
unknown.
Recommendation 2: That the proponent is requested to provide more thorough and comprehensive predictions of
the direct, indirect and cumulative impacts on subterranean PECs and associated taxa for a consolidated
assessment.
Discussion: The PER does not provide adequate information for Parks and Wildlife to provide informed advice on
the risk of the proposal on the PECs or associated taxa. A more in-depth description of the proposed direct and
indirect (including cumulative) impacts on this factor is warranted given the risk of impacts presented by the
proposal (this would be consistent with ESD requirements 6, 8 and 9 in particular).
Examples of issues leading to difficulties in reviewing information presented in relation to the PECs and associated
taxa are provided below:
1. Estimates of indirect impacts do not appear to take into account changes to natural physico-chemical
gradients in aquifers supporting the subterranean fauna PECs.
Yilgarn calcrete aquifers are characterised by strong salinity gradients, with salinity concentrations increasing
both horizontally towards the playa, and with depth. A freshwater surface layer can reach hypersaline conditions
within three metres. Subterranean fauna lnteract with these complex physico- chemical gradients, with species
distributions expected to reflect individual species' tolerances to salinity and other chemical, physical and
biological parameters. Project components with the potential to alter these complex physico-chemical gradients
therefore have the potential to significantly impact the Priority 1 PECs and associated taxa.
The less saline surface layer in the aquifer is likely derived from local recharge. Therefore, changes to the ground
surface, such as compaction or the placement of stockpiles, or to surface water flows from channel diversions,
bunds and roads, will change infiltration rates of fresh water from the surface. Pumping from, and injection into,
aquifers may also significantly alter the complex physico-chemical gradients, depending on whether groundwater
is pumped from the aquifer surface or at depth, and how water with different chemical characteristics mixes and
disperses when injected. Predictions of changes to groundwater chemistry should also take account of potential
long term seepage from tailings in the pits.
Item
No.
Section
No./Title
Reviewer Comment I Advice
The proponent has focused on aquifer depth or thickness in relation to assessment and proposed
management of impacts on stygofauna. However, the depth, thickness or proportion of saturated calcrete
remaining after drawdown should not be considered adequate as the only basis for habitat assessment
unless it can be demonstrated that the chemical properties of the remaining groundwater provide suitable
habitat. Because there is not necessarily a simple relationship between the thickness of an aquifer and
its habitat suitability, an assessment on aquifer depth alone is not necessarily appropriate in determining
potential impacts on stygofauna. The assessment of impacts needs to focus on the availability of suitable
habitat (both physical and chemical characteristics) rather than simply on the depth or thickness of water
in the aquifer.
Disruption to haloclines and other physico-chemical gradients may have significant impacts on
subterranean fauna as it alters the habitat in which the taxa are able to persist. By not fully considering
the potential extents and magnitudes of these disruptions, the risks, and potential losses and degradation
of habitat and taxa, may be underestimated.
It is recommended that the impact on the PECs and associated taxa is reassessed in the context of
predicted changes to key habitat characteristics (haloclines and other physico-chemical gradients).
2. Subterranean fauna surv s have disproportionately sampled impact areas.
Ten non-impact stygofauna (12.2% of the total 82 sample sites), and eight non-impact troglofauna (1% of
the total 97 sample sites) sites were sampled at Hinkler Well, and eight non-impact stygofauna (9.2% of
the total 87 sample sites) and four non-impact troglofauna (6.5% of the total 62 sample sites) sites were
sampled at the Barawidgee Calcrete.
While acknowledging the difficulties associated with sampling rare and restricted species,
disproportionate sampling of impact sites has not assisted in presenting a clear understanding of risk to
the PECs or associated taxa in the PER. Ideally, additional surveys focused on increased sampling effort
outside areas of impact within the calcretes proposed to be impacted would be conducted to improve
certainty with regard to levels of impact.
Based on the information presented, the proposal appears to increase the number of taxa recorded only
within areas proposed for direct and indirect impact.
3. There is insufficient information presented to support inferred broader distributions of subterranean fauna
taxa.
Item
No.
Section
No./Title
Reviewer Comment I Advice
The PER includes a series of statements indicating that distributions of individual taxa are 'expected' to
be much broader based on distribution of habitat. For example, "...there is no plausible basis for
assuming that species so far observed only within proposed disturbance areas are restricted to those
areas (unless they are reliant on high uranium habitats). Failure to collect a species from outside the
impact areas is almost certainly an artifact of sampling" (page 12-40).
The PER justifies the conclusion that taxa found only in areas associated with the proposed mine
expansion are not at risk based on:
• assumptions of rarity and therefore low chances of collection outside areas of impact;
• records of other species found both within and outside impact areas to demonstrate habitat
connectivity;
• wide salinity tolerances and distributions of genetically similar species with the assumption that
closely related species have similar distributions;
• short operational time frames for mining and dewatering; and
• the removal of only a small portion of overall available habitat.
In relation to this aspect the following observations are provided:
• Research (Guzik et al., 2009; Guzik et al., 2011; Ashyhr et al., 2013; Bradford et al., 2013) and
evidence from other surveys (like those conducted at Yeelirrie) are consistent with subterranean
calcrete systems being dynamic, and non-uniform habitats, and consequently,a proportion of taxa in
Yilgarn calcrete PECs may be restricted to single locations and not connected across their range
even within individualcalcretes.
• Geographical restriction is a genuine biogeographical/ecological phenomenon and many, even very
closely related species, have widely differing distributions because species diverge and exhibit
distribution patterns that match their specialisations.
A number of statements in the PER relating to the likelihood of broader species distributions are not
supported by survey data or other habitat related information, and instead, appear to rely on the
distributions of other taxa and assumptions of uniformity and connectivity throughout calcrete systems.
Predictions of this nature are considered unreliable and insufficiently robust to form the basis of
conclusions that apparently restricted species are not at risk.
4. n
I formation for the assessment of impacts has not been orovided.
In some key areas there is an absence of important information that would provide for an informed
assessment of impacts on subterranean fauna PECs. For example:
• The PER makes reference to the occurrence of fauna in other calcrete assemblages in support of
Item
No.
Section
No./Title
Reviewer Comment I Advice
•
conclusions that species are widespread and therefore not at risk. However, the PER does not
indicate whether these other assemblages are also subject to development or are located within
mining tenure and therefore under threat. Without this information an assessment of cumulative
impacts on taxa cannot be readily conducted.
The PER does not discuss the risk to taxa that appear to have a high proportion of their known
records I distributions in the predicted impact zone. This is particularly significant for taxa apparently
endemic to the proposal areas. The impact of the proposal on those taxa with distributions largely
centred on the proposed impact area should be considered and could be significant to the
persistence of those taxa in the wild, especially if they may be restricted to that calcrete assemblage.
5. The PEC boundaries are indicative.
The boundaries of the PECs currently reflect approximate mapping of calcrete aquifers taken from broad
geological mapping and may therefore not accurately reflect the actual distribution of the aquifer or fauna!
assemblages. The locations, spatial dimensions and definitions of PECs in Western Australia are
frequently refined over time as a result of new scientific information provided through additional
investigations, like those conducted for this proposal. The mapped boundaries of the PECs could be
refined based on the information from surveys conducted and then these boundaries used to estimate
habitat losses in order to more accurately reflect the extents of calcrete habitat and all indirect impacts,
including areas subject to altered water quality .
The refined calcrete mapping in the PER (Figure 12.1) appears to be at a more detailed scale and may
better reflect the habitat and distribution of the PEC assemblages. The PER maps indicate that only a
portion of the areas within the administrative PEC boundaries are characterised by calcrete habitat. The
proponent has estimated the area of Priority 1 Hinkler Well PEC subject to direct and indirect impacts to
be 6.79% of the total area within the PEC administrative boundary, and makes repeated reference to
proposal impacts being limited to very small proportions of the overall extent of the calcrete (pages 12-42
and 12-44). However, the same area of direct and indirect impacts is equivalent to 18.7% of PEC calcrete
habitat based on the 8,000 hectares of mapped calcrete (page 12-29).
The area of mapped calcrete habitat at Barwidgee has not been provided in the PER text, but based on
site mapping (Figure 12.1), it would appear that only about half of the area within the PEC administrative
boundary is characterised by calcrete. As a result, the estimated 13.4% of the area within the PEC
administrative boundary subject to direct and indirect impacts may more realistically equate to
approximately 27% of the calcrete habitat.
OTHER
Item
No.
Section
No./Title
Management
Reviewer Comment I Advice
Recommendation 3: That if the proposal is considered favourably for approval, management plans addressing
Vegetation and Flora, Groundwater Dependent Vegetation, Groundwater Drawdown, and Subterranean Fauna
be further refined in consultation with Parks and Wildlife, and other key specialists like the Western Australian
Museum.
Discussion:The proposed management frameworks for conservation significant flora and communities and the
Priority 1 subterranean PECs and associate taxa are insufficiently detailed to demonstrate that impacts could be
monitored and managed within defined limits.
The following management plans included in the PER provide outline summaries of proposed management of
environmental impacts and risks:
• Vegetation and Flora Management Plan.
• Groundwater Dependent Vegetation Management Plan.
Groundwater Drawdown Management Plan.
• Subterranean Fauna Management Plan.
•
5
However, there are a number of deficiencies in these plans including:
a) The plans do not explain all sample methods, or identify all sample sites in relation to monitoring of areas
potentially affected by indirect impacts or include provision for controlsites outside the zone of influence
for the proposal.
b) Proposed monitoring frequencies (e.g.annual subterranean fauna and vegetation health monitoring,and
the monthly collection of water quality data) are unlikely to be adequate for ensuring that management
response times are applicable to potential rates of environmental change.
c) The plans do not outline the proposed application of statistical tests and levels of significance to
determine if changes are occurring, for example vegetation health at impact sites compared to reference
sites, or between baseline and time sequenced subterranean fauna monitoring data.
d) Proposed management responses do not appear to be tiered or include criteria that would provide timely
warnings that impacts are tracking towards defined acceptable limits before those limits are reached.
Implementation of proposed monitoring and management frameworks summarised in the management plans
also appear likely to present significant practical challenges given the difficulties associated with identification of
Tecticornia species, detecting subterranean fauna , interpreting aquifer measurements to reliably distinguish
between natural fluctuations and project induced changes, and measuring the integrity of haloclines and other
physico-chemical gradients. These potential difficulties are not addressed in the plans in sufficient detail to
demonstrate that they can be overcome and do not inhibit the proposed management.
Item
No.
Section
No./Title
Reviewer Comment I Advice
Given the lack of information relating to conservation significant Tecticornia taxa, the vulnerability of
subterranean assemblages, and the level of practical difficulties associated with aquifer and both Tecticornia and
subterranean fauna monitoring and management, the summary outlines of proposed management may not
provide a sufficiently precautionary management framework.
Residual
impacts and
mitigation
Comment: The PER concludes that there would be no residual impacts on flora and vegetation or Priority 1
PECs following closure and rehabilitation of the proposed uranium mine expansion proposal. including the
following statements:
• "All impacts to the environment can be managed through avoidance, minimisation and rehabilitation and
there would be no residual impacts" (page 17-5).
• "Any impacts associated with implementation and subsequent closure of the Proposal would be avoided,
minimised or rehabilitated, so that there were no material residual impacts required to
be
counterbalanced by the application of offsets" (page 17-5).
Conservation significant Tecticornia
The PER states that "...the uncertainty su"ounding Tecticornia species has been somewhat resolved by the
additional work undertaken by Toro, Eco/ogia and the Western Australian Herbarium to inform this assessment
of the proposed extension to the Wiluna Project" (page 17-5).
6
Although staff of the Western Australian Herbarium have assisted with laboratory identification of some
Tecticornia specimens from the project area, Tecticornia taxonomy at Lake Way and Lake Maitland requires
further resolution and the diversity and distribution of Tecticornia taxa and associated communities within and
beyond the proposal area is uncertain due to information deficiencies and difficulty with identifications.
Completion of the survey and research work identified in Condition 8 of Ministerial Statement 913 would
substantially improve the state of knowledge and understanding of species taxonomy, distribution and ecology,
noting that work is not required to have commenced.
The PER indicates that the proponent anticipates that proposed research required under Ministerial Statement
913 will provide the necessary understanding and skills to successfully reinstate Tecticornia dominated
vegetation units. The proponent concludes that "...there would be no residual impacts on either described or
currently undescribed species" (page 17-5) and "It is therefore considered unlikely that there would be any
residual impacts on Tecticornia species, communities and populations post mine closure" (page 17-5).
The proponent reports some success in relation to regrowth of Tecticornia on small areas that have been
disturbed for short periods. However, the parameters used to define 'success' are not provided. A suitable plan
that indicates how this research would determine methods of rehabilitation has not been provided and it is
Item
No.
Section
No./Title
Reviewer Comment I Advice
unclear how the proponent would be able to reinstate Tecticornia dominated vegetation units that are currently
incompletely characterised and unmapped. With vegetation clearing required as one of the first stages of mining,
it is unlikely that results of research yet to be commenced will provide the necessary level of understanding to
support the successful reinstatement of vegetation and associated conservation significant species in the long
term (especially as recovery of aquifers is anticipated to take decades). The complete reinstatement of
Tecticornia species and communities may not be realistic and residual impacts and risks currently appear likely.
Priority 1 subterranean PECs
In relation to Priority 1 subterranean PECs, the proposal would appear likely to result in residual impacts and
risks to conservation significant subterranean assemblages that may be significant. In addition, the lack of detail
provided about, and practical difficulties associated with, the proposed management frameworks provides limited
confidence that the predicted levels of impact will be limited to those presented in the PER.
Consolidation
statement
7
Reinjection
8
I
I
Comment: It is noted that the current proposal represents an expansion of an approved mine development and
should the proposed expansion be approved, a consolidated Ministerial Statement 913 will be developed to
include the original approved Wiluna Uranium Mine and this proposed expansion. It is noted that, if the proposal
is considered for approval, additional targeted consultation on draft conditions developed for a consolidated
statement will occur with Parks and Wildlife on matters for which the department has responsibilities.
Recommendation 4: That if the proposal is considered acceptable, the disposal site for hypersaline waste water
I be
reviewed based on consideration of discharging I reinjecting water in areas with the lowest potential
environmental impact.
Discussion: The PER indicates that the proponent intends to reinject hypersaline water as a mitigation measure
to manage drawdown impacts on groundwater dependent vegetation into the Barwidgee PEC. However,
Tecticornia-domi nated assemblages and associated conservation significant taxa may be significantly impacted
by altered salinities associated with the reinjection of hypersaline waste water. Identifying the appropriate
I balance between maintaining groundwater depths for vegetation, and limiting disruption to salinities, haloclines
and other physico-chemical gradients of importance to both vegetation and stygofauna assemblages requires
further consideration.
The following statement in Appendix 10.35 recommending alternative reinjection sites are investigated is
supported by Parks and Wildlife: "The proposed placement of the reinjection bores on the actual Barwidgee
calcrete where the upper groundwater is three to five times less saline that the groundwater within the proposed
pit areas that would be reinjected, would pose risk to the integrity of the calcrete habitat hosting the Barwidgee
calcrete Priority Ecological Community. It is recommende(/ t11at alternative reinjection sites where groundwaters
are of comparable quality be further investigated ' (page 23).
A.3 Conservation Council of Western Australia, the
Australian Conservation Foundation, Friends of the Earth
Australia, The Wilderness Society, the Anti Nuclear Alliance of
WA and the West Australia Nuclear Free Alliance (CCWA) Per
comments
Wiluna Extension Uranium Project PER comments received from CCWA, dated
February 8, 2016.
Subterranean Fauna:
In this section we go through the various studies of each area – Centipede, Millipede, Lake
Way, West Creek Bore and Lake Maitland and then make some overarching comments
about assumptions on habitat and the possible range of species.
Centipede:
In the review of impacts to stygofauna and troglofauna conducted by MWH in 2015 Appendix 10.35 - MWH note the following species at Centipede that could be impacted):
 “three (9%) species are not known to have distribution ranges that extend beyond
the proposed mining area;”– “Brevisomabathynella sp. SAM2 (Bathynellacea);
Schizopera sp. TK4 (Copepoda); and Schizopera sp. TK7 (Copepoda).”
 “one (3%) species, is not known to have a distribution range that extends beyond
the modelled 0.5 m drawdown contour - Schizopera sp. TK10 (Copepoda).”
 “The removal of habitat through the lowering of the groundwater table through
mine pit dewatering poses a risk to one species Schizopera sp. TK10 whose
distribution was not recorded from beyond the 0.5 m modelled drawdown zone.”
MWH say it is possible for these species to exist outside the impact area because of suitable
habitat. There is no description of what constitutes as suitable habitat or what the habitat
requirements are for the four species mentioned above. MWH also discussed the usefulness
of surrogates to assess likely distributions – we are of the view that the use of surrogates is
not sufficient in providing evidence of distribution particularly given the high diversity and
levels of endemism of subterranean fauna.
Millipede:
MWH note the amphipod Chiltoniidae-SAM6 at Millipede could be impacted:
 “The amphipod Chiltoniidae-SAM6 that had not been recorded previously was the
only stygofauna species not found from beyond the proposed Millipede pit
boundary…. The amphipod species, Chiltoniidae-SAM6, has been collected from two
bores within the proposed Millipede pit area only. Additional Chiltoniidae specimens
were collected from Millipede but DNA sequencing was unsuccessful so these species
remain indeterminate. The seemingly restricted distribution of Chiltoniidae-SAM6 to
within the proposed mine pit impact means this species is of potential conservation
concern….The proposed Millipede pit excavation poses a risk to the conservation of
one stygofauna species, the amphipod Chiltoniidae-SAM6 that had not been
recorded previously, and was the only stygofauna species not to have been found
from beyond the proposed Millipede pit boundary.…. The amphipod, ChiltoniidaeSAM6, was recorded from two Millipede bores only, Gt12 and Gt1-A. It is not possible
to reliably assess the distribution range of stygofauna species that are known from
only one or two bores. The seemingly restricted distribution of a species to a single
bore is likely to be an artefact of that species occurring at low population densities
and/or possessing an irregular distribution in response to varying habitat factors,
biological interactions and availability of energy resources (Boulton 2000, Boulton et
al. 1998, Humphreys 2009). “
The diversity of the habitat features within the Hinkler Well calcrete delta has not been
described. The habitat requirements and range of each of these species have not been
described. The rate of change to habitat has not been described. Assumptions about the
ability of these species to survive in other parts of the Hinkler Well calcrete delta have not
been supported with evidence.
Lake Way:
MWH note the following conservation significant species at Lake Way that could be
impacted by the removal of habitat and the lowering of the groundwater table as none of
these species were recorded below the 0.5m modelled drawdown zone:
 Paramelitidae sp. SAM2 (Amphipoda);
 Brevisomabathynella sp. OES6 (Bathynellacea); and
 Parapseudoleptomesochra sp. ?TK2 (Copepoda).”
MWH suggest that these three species could occur outside the impact area of the mine and
drawdown area because there are parts of the Uramurdah calcrete system that will not be
affected and has suitable habitat. There is no further description about what constitutes as
suitable habitat and no identification of the specific habitat requirements of each of the
three species. There is no description of diversity of habitat in the Uramurdah calcrete
system.
West Creek Bore:
MWH note the following species at West Creek Bore could be impacted as none of these
species have been identified outside the 0.5m drawdown zone:
• Chiltoniidae sp. SAM2 (Amphipoda);
• Brevisomabathynella sp. SAM3 (Bathynellacea);
• Brevisomabathynella sp. SAM4 (Bathynellacea);
• Parabathynellidae sp. OES13 (Bathynellacea); and
• Parapseudoleptomesochra sp. TK2 (Copepoda).
MWH refer to previous use of the bore and ability for the population to re-establish itself.
There are a number of unknown quantities here that should be considered and further
explained – how long was the bore used for previously and what was the maximum
drawdown from using the bore – how does the previous use compare to the proposed use?
What were the species found before the bore was in use and what were the species found
after the level or water in the bore recovered? Was there a change in the population and
diverstiy? MWH again suggest that these five species could occur outside the impact area of
the mine and drawdown area because of other connected suitable habitat. Again there is no
description of what constitutes as suitable habitat, there is no description of the diversity of
habitat within the aquifer, or the specific habitat requirements of the five species.
Lake Maitland:
MWH note the following species at Lake Maitland that could be impacted:
 “The removal of habitat through mining excavation poses a risk to two of the three
species that are of conservation concern. These are Chiltoniidae sp. SAM4 and
Schizopera sp. TK1.”
 “The removal of habitat through the lowering of the groundwater table through
mine pit dewatering poses a risk to Haloniscus sp. OES1, one of the three species
that are of conservation concern.”
MWH again suggest that these five species could occur outside the impact area of the mine
and drawdown area because of other connected suitable habitat. There is no description of
what constitutes as suitable habitat, there is no description of diversity of habitat within the
Lake Maitland delta and no description of the habitat requirements of the three species
listed above.
MWH note that the current proposal of reinjecting hypersaline water into fresh or brackish
water has not been assessed for impacts on subterranean fauna and groundwater
dependent ecosystems and poses a serious threat to the quality of water and the habitat for
subterranean fauna.
Reinjecting hypersaline water into stygofauna fauna habitat will drastically change the
salinity and habitat – it is unlikely stygofauna will survive such rapid change in salinity.
Though stygofauna are known to live in hypersaline environments, they can adapt to gradual
change to salinity, during periods of low rainfall as levels of salinity slowly increases or
during rain when fresh water slowly infiltrates the calcrete. Re-injecting hypersaline water
will almost certainly cause a large number of species to die.
Aspects of habitat for further consideration:
The impacts to water quality and habitat from tailings seepage has not been effectively
considered as an impact to stygofauna. In the Environmental Management Plan – Appendix
4 – Toro suggest tailings will not have an impact on stygofauna. They include a link to the
CSIRO study – Appendix 10.29 – as if to suggest this report considers impacts to stygofauna in this study there is not a single mention of stygofauna. The reduction of habitat in addition
to the impacts of pollution in habitat and water quality should be considered in detail and
presented.
Consultants have suggested there is ample habitat and habitat connectivity but have not
described the features of suitable habitat. Calcrete is just one overarching feature of the
habitat within calcrete there are many be many features. Impacts to those habitat features
have not been adequately addressed and so assumptions on the ability for stygofauna to
relocate to other parts of the calcrete are unfounded.
Some habitat features and issues are listed below:
1. Habitat is three dimensional – often there are gradients for example there might be
fresh water on top and saline or hypersaline water underneath. There may be some
2.
3.
4.
5.
movement of species between gradients but only within certain ranges and would occur
gradually.
The drawdown of water could impact on the gradients by concentrating salinity in lower
gradients making that habitat prohibitive for some species.
Rapid change to habitat could – increasing salinity – is likely to lead to a high mortality
rate
Re-injection of hypersaline water into brackish or saline water will drastically change the
habitat and will almost certainly result in a high mortality rate.
Habitat features include - water quality, suitability, ph variability, salinity, dissolved oxygen, and
calcrete physical structure – transmisivity of alluvial or transitional calcrete. Without
understanding the specific habitat features that support individual species and without
understanding the specific impacts to habitat no conclusions can be made about impacts to
stygofauna.
There is a tendency to use surrogates to suggest a species is more widespread than what is
demonstrated with evidence. We note that the new EPA guidelines have weakened the need for
evidence in this area. The high levels of diversity and endemism in subterranean fauna and particularly
stygofauna amplify the threats to individual species survival, hence our concern in this area.
We urge the EPA to recommend additional studies on water quality, ph variability, salinity, dissolved
oxygen, and transmisivity of alluvial or transitional calcrete feature within each of the aquifers and
deltas to determine the ability for species to migrate into suitable habitat.
We recommend further studies are conducted to provide evidence on the habitat range of the
following species that are currently only found in the impact area of mining and dewatering:
 Centipede: Schizopera sp. TK10
 Millipede: amphipod Chiltoniidae-SAM6, Schizopera sp. TK10 (Copepoda) Brevisomabathynella
sp. SAM2 (Bathynellacea); Schizopera sp. TK4 (Copepoda); and Schizopera sp. TK7 (Copepoda)
 Lake Way: Paramelitidae sp. SAM2 (Amphipoda); Brevisomabathynella sp. OES6
(Bathynellacea); and Parapseudoleptomesochra sp. ?TK2 (Copepoda).”
 West Creek Bore: Chiltoniidae sp. SAM2 (Amphipoda); Brevisomabathynella sp. SAM3
(Bathynellacea); Brevisomabathynella sp. SAM4 (Bathynellacea); Parabathynellidae sp. OES13
(Bathynellacea); and Parapseudoleptomesochra sp. TK2 (Copepoda).
 Lake Maitland: Haloniscus sp. OES1; Chiltoniidae sp. SAM4 and Schizopera sp. TK1.
Appendix B
Recorded natural groundwater level
fluctuations from Wiluna Project Areas
Millipede and Centipede.
Data from Toro Energy Ltd groundwater monitoring
Figure B-1: Locations of groundwater monitoring bores.
Figure B-2: Recorded natural groundwater level fluctuations from East Shallow monitoring bore.
Figure B-3: Recorded natural groundwater level fluctuations from East Deep monitoring bore.
Figure B-4: Recorded natural groundwater level fluctuations from North Shallow monitoring bore.
Figure B-5: Recorded natural groundwater level fluctuations from North Deep monitoring bore.
Figure B-6: Recorded natural groundwater level fluctuations from SW Shallow monitoring bore.
Figure B-7: Recorded natural groundwater level fluctuations from SW Deep monitoring bore.
Figure B-8: Recorded natural groundwater level fluctuations from WB003 monitoring bore.
Figure B-9: Recorded natural groundwater level fluctuations from WB009 monitoring bore.
Appendix C
Recorded diversity and distributions of
the Hinkler Well calcrete stygofauna
PEC.
Data from Outback Ecology (2012b) and MWH (2015)
Table C-1: Stygofauna diversity and distributions recorded from 2007 to 2015 surveys in relation to
proposed Project including the Millipede extension. Taxon occurrences from published records are
also included (). Identified species and morphospecies shaded in: orange found in Millipede
mining area only; green found in Centipede mining area only; yellow found within groundwater
drawdown > 0.5 m. (This table, with minor modifications, also presented as Table 12.6 in PER (Toro
Energy Limited 2015) and Table 3-2 in MWH (2015). Modifications are that specimens that could not
be positively identified to species (labelled with a ?) have been removed from this table).
Impact
Millipede/Centipede Project
Survey Area Taxa
Total
Abundance
Mining Area
Millipede
Centipede
Non-Imapct
> 0.5 m
Drawdown
< 0.5 m
Drawdown
√
√
√
√

Occur
Outside
Project
Survey Area
Amphipoda
Chiltoniidae sp. SAM3
Chiltoniidae sp. SAM5
141
7
Chiltoniidae sp. SAM6
51
√
√
Bathynellacea
Bathynellidae
1
Atopob athynella wattsi
Atopob athynella sp. OES5
645
51
√
√
Brevisomab athynella sp. SAM2
20
√
134
√

√
Coleoptera
Limb odessus hinkleri
Limb odessus macrohinkleri
Limb odessus raeae
2
√
√
√


Copepoda: Cyclopoida
Dussartcyclops uniarticulatus
Fierscyclops fiersi
5
434
√
Halicyclops amb iguus
Halicyclops eb erhardi
539
√
Halicyclops kieferi
Metacyclops laurentiisae
√
√
√
√

√
√
√
√
√
√
√
√
√
2
300
√
√
Copepoda: Harpacticoida
Ameiropsyllus sp. TK1
Australocamptus similis
4
6
√
Haifameira pori
Kinnecaris lakewayi
Nitokra lacustris pacifica
16
1
Nitokra sp. TK1
29
√
√
Nitokra sp. TK2
Parapseudoleptomesochra sp. TK1
32
14
√
√
Parapseudoleptomesochra sp. TK2
Parapseudoleptomesochra karamani
√
√
√
1

√
√
√
√
√
√
√
√
√
√
√

√
√
Schizopera austindownsi
31
√
√
√
√
Schizopera uramurdahi
Schizopera sp. TK4
27
1
√
√
√
√
√
Schizopera sp. TK7
22
√
√
Schizopera sp. TK10
2
√
√
Oligochaeta
Enchytraeidae-OES20
Naididae-OES2
21
2
Phreodrilidae-OES21
8
√
√
√
√
√
√
Ostracoda
Candonopsis (Ab candonopsis) linnaei
Candonopsis sp. IK2
16
1
√
√
√
√
Figure C-1: Distribution of Amphipoda species recorded from 2007 to 2015 within the Hinkler Well calcrete (Figure 3-5 in MWH (2015)).
Figure C-2: Distribution of Bathynellacea species recorded from 2007 to 2015 within the Hinkler Well calcrete (Figure 3-6 in MWH
(2015)).
Figure C-3: Distribution of diving beetle species recorded from 2007 to 2015 within the Hinkler Well calcrete (Figure 3-7 in MWH
(2015)).
Figure C-4: Distribution of Cyclopoida copepod species recorded from 2007 to 2015 within the Hinkler Well calcrete (Figure 3-8 in
MWH (2015)).
Figure C-5: Distribution of Harpacticoida copepod species recorded from 2007 to 2015 within the Hinkler Well calcrete (Figure 3-9 in
MWH (2015)).
Figure C-6: Distribution of Oligochaeta recorded from 2007 to 2015 within the Hinkler Well calcrete (Figure 3-10 in MWH (2015)).
Figure C-7: Distribution of Ostracoda species recorded from 2007 to 2015 within the Hinkler Well calcrete (Figure 3-11 in MWH (2015)).
Appendix D
Recorded diversity and distributions of
the Barwidgee calcrete stygofauna PEC.
Data from Outback Ecology (2012a)
Table D-1: Stygofauna species diversity, abundance and distribution. Identified species and
morphospecies shaded in orange found to date in resource area only. H= Hinkler Well calcrete; LV =
Lake Violet calcrete; WS = widespread in region. (This table, with minor modifications, presented as
Table 12.9 in PER (Toro Energy Limited 2015) and Table 5 in (Outback Ecology (2012a)). Modifications
are that specimens that could not be positively identified to species have been removed from this
table).
LMUP Impact
Taxa
Abundance
Regional LMUP Non- Mining operations area Borefield
Distribution
impact
> 0.5 m
> 0.5 m
Resource
Drawdown
Drawdown
Amphipoda: Chiltoniidae
Chiltoniidae sp. OES1*
45
Chiltoniidae sp. SAM4*
3
Bathynellacea: Parabathynellidae
Atopobathynella sp. OES6*
2
Bathynellidae
Bathynellidae sp. OES1
1
Coleoptera: Dytiscidae
Limbodessus barwidgeensis*
2
Limbodessus usitatus #
Copepoda: Cyclopoida: Cyclopidae
Halicyclops sp. TK1
112
Halicyclops sp. TK2
279
Halicyclops sp. TK3
9
Mesocyclops brook si
2
Microcyclops varicans
3
Harpacticoida: Ameiridae
Ameiropsyllus sp. TK1
1
Nitok ra lacustris pacifica
10
Nitok ra sp. TK3
16
Canthocamptidae
Australocamptus similis
5
Parastenocarididae
Kinnecaris sp. TK3
52
Miraciidae
Schizopera sp. TK1
7
Schizopera sp. TK5
9
Schizopera sp. TK6
53
Schizopera sp. TK8
12
Isopoda: Scyphacidae
Haloniscus sp. OES1
15
Oligochaeta: Enchytraeidae
Enchytraeidae sp. OES1
52
Enchytraeidae sp. OES2
35
Naididae
Naididae sp. OES1
2
Naididae sp. OES2
20
Ostracoda: Podocopida: Candonidae
Candonopsis dani
38
Candonopsis sp. IK2
2
* Included in DNA analysis (Appendix I);
#
√
√
√
√
√
√
√
√
√
WS
WS
H
WS
√
√
√
√
√
√
√
√
√
√
H, LV
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
LV
Not collected in this study
√
√
√
√
Figure D-1: Distribution of Amphipoda species recorded within the Barwidgee calcrete system.
Figure D-2: Distribution of Halicyclops (Copepoda) species recorded within Barwidgee calcrete system.
Figure D-3: Distribution of Schizopera (Copepoda) species recorded within Barwidgee calcrete system
Figure D-4: Distributions of Ameiropsyllus, Australocamptus, Kinnecaris, Microcyclops, Nitokra (Copepoda) species recorded within
Barwidgee calcrete system.
Figure D-5: Distributions of Bathynellacea and Dytiscidae species recorded within Barwidgee calcrete system
Figure D-6: Distributions of Oligochaeta species recorded within Barwidgee calcrete system.
Figure D-7: Distributions of Isopoda and Ostracoda species recorded within Barwidgee calcrete system
Appendix E
Over all stygofauna species diversity and
distribution in relation to Lake Way
associated Project survey areas
presented in Outback Ecology (2012b).
Table E-1: Over all stygofauna species diversity and distribution in relation to Lake Way
associated Project survey areas. Includes species recorded in published records and Western
Australian Museum database. Identified species and morphospecies shaded in: orange found to
date in mining area only; yellow found within groundwater drawdown > 0.5 m. This table was
presented as Table 6 in Outback Ecology (2012b).
Project Survey Areas
Toro Wiluna Uranium Project Taxa
Centipede Lake Way
Amphipoda
Chiltoniidae sp. SAM1a
Chiltoniidae sp. SAM1b
Chiltoniidae sp. SAM2
Chiltoniidae sp. SAM3
Chiltoniidae sp. SAM5
Paramelitidae sp. SAM1
Paramelitidae sp. SAM2
Bathynellacea
Atopob athynella wattsi
Atopob athynella sp. OES5
Brevisomab athynella clayi
Brevisomab athynella uramurdahensis
Brevisomab athynella sp. OES5
Brevisomab athynella sp. OES6
Brevisomab athynella sp. SAM2
Brevisomab athynella sp. SAM3
Brevisomab athynella sp. SAM4
Brevisomab athynella sp. SAM5
Brevisomab athynella sp. SAM6
Brevisomab athynella sp. SAM7
Brevisomab athynella sp. SAM15
Parabathynellidae sp. OES13
Bathynellidae
Coleoptera
Limb odessus hahni
Limb odessus hinkleri
Limb odessus insolitus
Limb odessus macrohinkleri
Limb odessus millb illiensis
Limb odessus morgani
Limb odessus raeae
Limb odessus wilunaensis
Copepoda: Cyclopoida
Dussartcyclops uniarticulatus
Fierscyclops fiersi
Halicyclops amb iguus
Halicyclops eb erhardi
Halicyclops kieferi
Mesocyclops b rooksi
Metacyclops laurentiisae
West
Creek
Occur in
calcretes
outside
Project
areas
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
Collected
in study
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
Table E-2 (cont.): Over all stygofauna species diversity and distribution in relation to Lake Way
associated Project survey areas. Includes species recorded in published records and West ern
Australian Museum database. Identified species and morphospecies shaded in: orange found to
date in mining area only; yellow found within groundwater drawdown > 0.5 m. Recreated from
Table 6 in Outback Ecology (2012b).
West
Creek
Occur in
calcretes
outside
Project
areas
Collected
in study
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
?√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
Project Survey Areas
Toro Wiluna Uranium Project Taxa
Centipede Lake Way
Copepoda: Harpacticoida
Ameiropsyllus sp. TK1
Australocamptus similis
Haifameira pori
Kinnecaris lakewayi*
Nitocrella trajani
Nitokra lacustris pacifica
Nitokra sp. TK1
Nitokra sp. TK2
Parapseudoleptomesochra karamani
Parapseudoleptomesochra rouchi
Parapseudoleptomesochra sp. TK1
Parapseudoleptomesochra sp. ?TK2
Parapseudoleptomesochra sp. TK2
Schizopera austindownsi
Schizopera uramurdahi
Schizopera sp. TK2
Schizopera sp. TK4
Schizopera sp. TK7
Schizopera sp. TK10
Isopoda
Andricophiloscia pedisetosa
Haloniscus sp. OES8
Haloniscus longiantennatus
Haloniscus stilifer
Oligochaeta
Enchytraeidae
Naididae
Phreodrilidae
Ostracoda
Candonopsis (Ab candonopsis) linnaei
Candonopsis dani
Candonopsis sp. IK1
Candonopsis sp. IK2
Gomphodella sp. IK1
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
?√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
?√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√