Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
1
Effective Mine Dust Control and Waste Rock
Dump Rehabilitation: a Case Study in Vietnam
P. N. Martens, R. Randaxhe, I. Özdemir & A. Förster,
Institute of Mining Engineering I, RWTH Aachen University, GER
M. Fuchsschwanz, Institute of Geotechnical Engineering,
RWTH Aachen University, GER
J. B. Pateiro Fernández, A. Filby, O. Nitzsche & K. Aygozhiev,
Brenk Systemplanung GmbH, GER
M. Bauer, T. Weyer & J. Schiffer, CBM GmbH, GER
This paper has been accepted as a “peer reviewed paper” by the scientific committee
ABSTRACT
Mining activities can cause several environmental impacts that, unless effectively
controlled, reduce productivity and increase operational costs. These environmental
problems caused by the hard coal mining industry in Vietnam and corresponding costeffective solutions were addressed within the RAME (Research Association Mining and
Environment in Vietnam) project. This paper presents the solution approach and the main
results of two RAME sub-projects, which focused on mine dust control and rehabilitation of
waste rock dumps at the study area, an open-pit hard coal mining area in Ha Long Bay,
Quang Ninh Province, Vietnam. The project outcomes are applicable for both active and
planned mining operations.
INTRODUCTION
Control of fugitive dust emissions from mining activities and rehabilitation of waste rock
dumps have gained significance especially due to the increasing public awareness of the
environmental impacts of mining and more stringent environmental legislation regarding
mining. Therefore, finding ecologically and economically acceptable solutions for these
problems is becoming more and more important.
Defining long-term dust control approaches during the mine planning phase has been
proven more cost-effective than reacting after dust emission problems arise (Environment
Australia [11]). Likewise, the proper design and construction of a dump site can
significantly reduce its environmental impact and operational costs (Ahmad [1]). However,
determining strategies addressing mine dust emission and waste rock dump stabilization
problems at all stages of mining is a challenging task because the extent of these
problems varies according to the local conditions (e.g., local climate) and the
characteristics of the mining activities. For this reason, reliable assessment of these
problems requires in-depth consideration of the location- and activity-specific conditions.
2
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
Effective dust control and waste rock dump rehabilitation approaches thus can be
developed on the basis of these site-specific assessments.
DESCRIPTION OF THE STUDY AREA
The research and development project RAME (Research Association Mining and
Environment in Vietnam) funded by the German Federal Ministry of Education and
Research (BMBF) was established to focus on environmental concepts as well as capacity
building for the hard coal mining industry in Vietnam. Within the framework of the RAME,
researchers from the Institute of Mining Engineering I of the RWTH Aachen University
carried out two sub-projects, namely “Dust Mitigation and Monitoring” and “Dump
Stabilization and Rehabilitation”, in collaboration with the Institute of Geotechnical
Engineering of the RWTH Aachen University and German consultancy companies, Brenk
Systemplanung and Gesellschaft für Consulting, Business and Management mbH (CBM)
as well as Vietnam National Coal-Mineral Industries Group (VINACOMIN). In these subprojects, the current situation at the chosen open-pit coal mine of the Nui Beo Coal
Company (NBCC), a subsidiary of the VINACOMIN, located in Ha Long Bay, Vietnam was
analyzed; and consequently cost-effective solutions were developed and implemented on
site.
The study area is located in the Quang Ninh province in the north of Vietnam (Figure 1). In
this region, hard coal mining is one of the core industries and provides most of the coal
production in Vietnam (Sinh [18]; USGS [23]). Due to the attraction of Ha Long Bay, a very
sensitive eco-system and moreover a UNESCO world heritage site, tourism is also a
considerable economic activity in this area.
Figure 1:
Maps, showing the location of the Quang Ninh Province in northern
Vietnam (MyGeo.info [16] and Wikimedia Foundation Inc. [24])
The NBCC employs conventional truck and shovel operation in two open pit mines east of
Ha Long (Quang Ninh Province, Vietnam). In Figure 6, the two open pits (OP 11 and OP
14, and the waste dump area (Chin Bac) are shown on a map. Between 2008 and 2012
coal production averaged 4.8 Mt/y with an average annual overburden removal of 20 Mm³.
Impacts on the environment arise particularly from fugitive dust emissions, generated from
various sources within and around the mines. Depending on weather conditions and the
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
3
quality of particulate matter, these solid, airborne particles disperse over a broad area and
may represent health and environmental hazards. Besides, the currently employed
overburden dumping method causes impacts due to stability and erosion problems (e.g.,
landslides). In addition, the mine dust emissions and the area requirement for the waste
rock dumping reinforce the land use conflict (settlement, industry, agriculture, tourism and
mining) in the region. The mining companies are aware of the arising environmental
problems and implement measures in order to mitigate their effects.
According to the meteorological data from the Bai Chay meteorological station in Ha Long,
the prevailing wind direction was north and the monthly average precipitation was 153 mm
in 2010 and 2011 (Bai Chay Meteorological Station [2]).
MINE DUST CONTROL
Fugitive dust emissions from surface coal mining activities can constitute environmental
health problems that can be avoided by implementing effective dust control strategies.
Before introducing these control strategies, the mine dust emission levels and the costperformance of the control methods should be evaluated.
Dust (particulate matter, PM) emissions are characterized by emission factors which relate
the emission level to the activity rate of the source, i.e., mining activity. The US
Environmental Protection Agency (USEPA) conducted a comprehensive study on the
subject and compiled the emission factors for western US surface coal mines in its AP-42
document, Section 11.9 (USEPA [20]; USEPA [21]). There have been also other studies
proposing emission factors for the surface coal mines in other countries, for instance in
India (Chakraborty, et al. [8]; Ghose [14]). However, the emission factors developed for a
certain mining location may misrepresent the dust emissions from the mining activities at
another mining location underlying different operational, geological and climatic conditions.
Similarly, a wide range of effectiveness levels (i.e., reduction factors) for the mine dust
control methods was provided in literature. As an example, different studies (USEPA [19];
USEPA [22]; Foley, Cropley, & Giummarra [13]; Countess Environmental [10];
Environment Australia [12] and NIOSH [17]) stated different reduction factors in a varying
range from 10 to 95% for water spraying, which is the most commonly method applied for
dust mitigation from mine haul roads. This variation in the reduction factors stems from the
differences in site-specific conditions (e.g., local climate), mining conditions (e.g., traffic
density) and application level of the control methods (e.g., watering rate).
Within this context, in order to investigate the dust emission problem and possible
solutions at the NBCC mining site, the location- and activity-specific mine dust emission
factors for the identified sources (i.e., mining activities) and the reduction factors for the
proposed control methods were derived. Furthermore, the level and extent of the mine
dust problem at the area were investigated by dust dispersion modeling. Subsequently,
dust mitigation measures were designed, tested and partly implemented. A computer
based dust control decision support system (DSS) was developed to evaluate mine dust
emission levels, costs and performance of proposed dust control approaches.
Identification of Mine Dust Sources
The dust-generating mining activities at the NBCC open-pit coal mine were categorized
into coal production and overburden handling chains (Table 1). The emission factors for
these activities were developed by real-time emission measurements followed by dust
dispersion modeling and statistical analyses.
The real-time emission measurements were aimed to quantify both the PM emissions from
the investigated mining activities and the parameters influencing the emissions, such as
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
4
wind conditions and activity rates. During these measurements, three to six mobile aerosol
spectrometers, Models 1.107 and 1.109 (Grimm) were used for PM measurements in an
upwind (UW) – downwind (DW) setup. In this setup, the upwind spectrometers evaluate
the PM concentrations caused by the source activity, whereas the downwind spectrometer
quantifies the background PM concentrations. The difference between the upwind and the
downwind PM levels provides the net emissions from the sources. The wind conditions
(i.e., wind direction and speed) were recorded by an ultrasonic anemometer (USA),
type USA-1 (Metek Meteorologische Messtechnik). The other parameters influencing the
emission levels were also evaluated for further emission analyses. As an example, during
the real-time measurements for truck haulage, the truck type and haul road surface
thickness were identified by visual observations, whereas the truck weight were taken from
the suppliers’ catalogues. Besides, the truck speed was calculated by measuring the travel
times of the trucks within the tested portion of the haul roads (from point A to point B in
Figure 2). The road surface material were sampled in regular intervals (ca. 1 hour) and
tested in the soil laboratory for particle size distribution, silt content and moisture content.
A photo taken during the real-time measurements for the truck haulage activity and the
sketch of the measurement setup are shown in Figure 2. The positions of the
spectrometers and the USA within the upwind-downwind setup are depicted in this figure.
Main Wind
Direction
Ultrasonic Anemometer
Spectrometer (DW)
Spectrometer (UW)
Figure 2:
Real-time emission measurement setup for truck haulage (November
2012)
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
5
The data obtained from the real-time measurements (PM emissions, atmospheric
conditions and spatial locations of the mining activities), were incorporated into the
conceptual site models generated individually for each mining activity listed in Table 1.
These models were then simulated with dispersion modeling tools (i.e., AUSTAL2000 and
LASAT) in order to estimate the emission rates at the source locations. The subsequent
statistical analyses of the emission rates provided the site-specific dust emission factors
for the studied mining activities (see Table 1).
In Table 1, the daily dust emissions from each mining activity and their corresponding
contributions to the total mine dust emission are also given. As it is seen in this table,
overburden truck haulage, which accounts for almost 54% of the total emission, is the
major dust-generating activity at the NBCC mining area. Together with the coal trucking,
the total material haulage in the mine constitutes approximately 63% of the total emission.
Mining Activity
Emission
Factor
Unit
Emission
Rate
Unit
Emission
Share
per day
(%)
(kg/day)
Overburden Handling
Drilling
Atlas Copco DML 28.17
Atlas Copco DM 45E 320.67
SBSH-250MNA-32 1279.8
Blasting
0.53
Loading
Hydraulic excavator 1 3.93
Hydraulic excavator 2 3.78
Coal Production
Chain excavator
Truck haulage
On dry main road
On wet main road
On dry side road
On dry side road
Dumping
Loading (raw coal)
Truck haulage
On dry main road
On wet main road
On dry side road
On dry side road
Unloading
Charging the plant
Screening sieve
Crusher
Dropping
Loading (processed coal)
Wind erosion
Table 1:
g TSP/t
0.355
3.810
8.509
3432.3
g TSP/t
0.800
0.670
g/s
g/s
g/s
g/s
g/s
g/s
g/s
4.70
0.810
g/s
880
524
1124
392
0.225
5.37
4.816
2.867
6.151
2.145
0.123
0.350
880
524
1124
392
0.22
52.8
1.2
9
4.5
5.37
0.198
g TSP/m
g PM10/km
/truck
g TSP/t
g TSP/t
g PM10/km
/truck
g TSP/t
g TSP/t
g TSP/t
g TSP/t
g TSP/t
g TSP/t
g TSP/m2/h
g/s/truck
g/s
g/s
4.816
2.867
g/s/truck
6.151
2.145
0.123
g/s
1.540
g/s
0.035
g/s
0.095
g/s
0.128
g/s
0.350
g/s
n.a.
n.a.
Total NBCC
200
0.32
41
<0.1
369
0.58
16685
9,935
17390
8201
27
86
2855
1827
3100
1079
2
850
14
38
72
86
21437
63253
26.38
27.49
<0.1
0.14
4.51
4.90
<0.1
1.34
<0.1
<0.1
0.11
0.14
33.89
100
Mine dust emission factors and emission levels for the NBCC mine
6
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
Implementation of Mine Dust Control
Upon identification of the dust-generating mining activities at the NBCC mine, site-specific
dust control methods and their individual effectivenesses (i.e., reduction factors) were
determined. Truck haulage activity was examined in detail at this stage since it was
designated as the primary dust source (see Table 1). Accordingly, the reduction factor of
water spraying, which is the only control method employed against dust generation from
trucking on haul roads (truck haulage) at the NBCC mining area, was estimated.
For this purpose, the real-time dust control performance measurements similar to the realtime emission measurements described above were conducted at the NBCC area. In
these measurements, the emission levels generated by the haulage activity under the
different watering rates were quantified with aerosol spectrometers. Accordingly, the actual
watering rate applied at the NBCC mining area, 0.38 l/m², and an improved rate, 0.50 l/m²,
with varying watering intervals from 10 minutes to 2 hours were tested. The concurrent
wind conditions (i.e., wind direction and speed) recorded with an ultrasonic anemometer
(USA). The PM emission levels obtained from the haulage activity under different watering
rates over time were then evaluated through dispersion modeling with LASAT. At this step,
a theoretical emission was assigned at the source area (haul road); and the LASAT model
simulated the emission levels at the measurement points. The calibration factors were
then estimated by comparing these simulated emissions with the emissions measured
real-time. On the basis of the calibration factors, the emissions from the haul road under
the actual and improved watering rates were computed. The percent changes in the
emission levels over varying watering durations provided the reduction factors for these
watering rates (0.38 and 0.50 l/m²). A third theoretical set of reduction factor for the water
spraying method with the watering rate of 0.60 l/m² at 30-minute watering intervals was
approximated as 70% by linear interpolation (see Table 2).
The reduction factors of the other control methods proposed for the NBCC mine are also
listed in Table 2. Some of these methods, e.g., water spraying for truck haulage as
explained above, are the dust control methods directly applied on site, whereas some
others, e.g., wet drilling, were referenced from previous studies, such as NIOSH [17]. The
reduction factors given in this table can be utilized for other mining sites applying these
methods under analogous conditions.
In addition to the mine dust emission and reduction factors developed for the NBCC mine,
the cost parameters of the proposed dust control methods were determined. Majority of
the cost parameters were valued in reference to the CostMine’s “Mine and Mill Equipment
Costs Estimator’s Guide” (CostMine [9]). Unit costs for water, electricity and fuel were
assigned according to the data obtained from public institutions, such as
(Landtag NRW, [15]). In order to define the rest of the unit costs for materials, e.g.,
additives used, and for equipment, e.g., spraying systems, relevant suppliers were
consulted.
The cost-performance parameters constituted the basis of the computational module of the
decision support system (DSS) that was developed as a part of the designed mine dust
control approach. The DSS includes a guidance module, i.e., best practice guide (BPG),
which is a document providing specific information on the dust control measures for openpit coal mines. The developed DSS is capable to estimate the dust emission levels of the
defined activities and the costs and dust reduction potentials of the selected control
methods for active or planned mining operations having similar mining practices.
The DSS was designed as a web application, which is available online for authorized
users of the RAME project. The DSS computational module was built by inserting the dust
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
7
control cost-performance parameters and the equations between them into a MySQL
database. At this point, PHP software (server-side scripting language) was used to
implement the web-application. The guide module (BPG) of the web-based DSS was
developed on Wiki-application (Wikimedia Foundation, Inc.).
Mining Activity
Dust Control Method
Drilling
Blasting
Wet drilling
Wetting the material
Wetting the working surface
Water spraying
Reducing dumping height
Wetting the working surface
Suggested
Suggested
Applied
Suggested
Applied
Dust
Reduction
Factor (%)
79
48
9
70
57
11
Wetting the material
Suggested
48
Water spraying
Wetting the working surface
Wetting the working surface
Paving & cleaning charging area
Wetting the material
Direct charge of the terminal
Wetting the material
Encase screening or crushing
units
Wetting the material
Avoid wind erosion with chute
Separate storage space from
cemented driving area
Wetting the working surface
Planting or seeding vegetation
Applied
Applied
Applied
Suggested
Applied
Suggested
Suggested
70
50
50
60
35
80
80
Suggested
20
Applied
Applied
80
30
Suggested
40
Applied
Applied
50
93
Overburden Loading
Handling
Truck haulage
Dumping
Loading (raw
coal)
Truck haulage
Unloading
Charging the
plant
Coal
Production Screening
sieve and
crusher
Dropping
Loading
(processed
coal)
Wind erosion
Table 2:
Method
Type
Suggested
Mine dust control methods and reduction factors for the NBCC mine
Overall Mine Dust Dispersion Modeling
Dust emitted into the atmosphere is dispersed by movements of air that carry it from the
sources and diffuse it into large volumes of air by turbulent eddies. To determine the
concentration of dust in the atmosphere and its deposition on surface a Lagrangian
mathematical model (LASAT) was used.
Input parameters of the model are:

meteorological data,

geometry of 3D-terrain, and

spatial location and time-dependent intensity of the dust sources.
The emission inventory of the total suspended particle (TSP) was divided into three groups
of particulate matter (PM50, PM10 and PM2.5) in which the same aerodynamic diameter,
the deposition velocity and the sedimentation velocity are used. Meteorological data and
time-dependent intensity of the dust sources were defined in form of time series (hourly
8
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
means over one year). The highly variable morphological structure of the Ha-long
Peninsula (including the NBCC open pit mine) has been transferred into the model as
nested-grid domains (see Figure 3).
Figure 3:
3D-Model of the open pit area as basis for subsequent dispersion
modelling with LASAT
Diagnostic model runs were done for the verification and visualization of dust
concentration distribution at certain times and in annual average (see Figure 4). These
model runs also validated the effectiveness of the proposed dust control methods.
Figure 4:
Spatial distribution of TSP concentration (annual average)
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
9
WASTE ROCK DUMP REHABILITATION
Waste rock dumping is an important mining activity due to its economic and environmental
implications. As a result of partly inadequate planning and management of the waste rock
dumps, stabilization and environmental problems, such as erosion, dust emissions,
groundwater contamination and acid mine drainage (AMD), can be encountered. In this
context, designing effective waste rock dump stabilization and environmental protection
measures have become an integral part of mine planning (Ahmad [1]).
The local conditions and the dumping method (side-hill dumping) employed at the NBCC
mining area were investigated with focus on slope stability and environmental issues.
Accordingly, an alternative dumping method (layered dumping) for these problems was
designed and tested. Long-term water quality prediction models were developed to assess
the contaminant concentration evolution in the seepage and ground water and different
rehabilitation alternatives addressing AMD reduction and long-term groundwater protection
were compared. In addition, monitoring concepts for the geotechnical stability of waste
dumps, discharge of pollutants, as well as dump fire risks were introduced. The study
outcomes were then transferred into a web-based DSS assisting in waste dump
construction and rehabilitation.
Waste Rock Dump and Problems
The stability of a waste rock dump depends, among other factors such as the dumped
material and the underground, on the chosen dumping methods. Due to the limited space
available in the NBCC mining area, the dumps were built up to 200 m high employing the
side-hill dumping method, which can be performed in two different ways. Most common is
the so-called “end-dumping method” where the overburden is dumped directly from the
truck over the dump edge. The “short-dumping method” is used where the dump is
unstable: The overburden is unloaded on the slope edge first and then moved over the
edge by bulldozers.
Both methods have an influence on the geotechnical stability and segregation of the waste
rock material as they lead to steep slope angles between 30° and 50°. No compaction of
the rock material was undertaken by NBCC. Therefore, the dumped material has low bulk
densities causing settling processes. As a result, cracks are plainly visible on top of the
dump (see Figure 5).
The cracks affect the water, gas and mass balance of the dump as they lead to an
increased infiltration of rainwater and thus inner erosion. Oxygen intrusion into the waste
dump is facilitated as well, increasing the formation of acid mine drainage (AMD) and the
risk of dump fires, especially in the older parts dump (Thai Nam, see Figure 6) where one
dump fire was observed in August 2008.
Furthermore, the revegetation of the dump, especially on the slopes, is paramount to
impair the occurrence of landslides, erosion and dust emission. However, adequate
measures for preventing landslides and erosion are not realizable due to the steep slope
angles.
10
Figure 5:
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
Cracks on top of the waste rock dump Chinh Bac (November 2011)
Rehabilitation of Waste Rock Dump
Compared to the side-hill dumping method described above, the dumping-in-layers
method holds several advantages. Dumping in layers requires the construction of the
dump bench by bench. Therefore, it is possible to plan the dump geometry including slope
angles and slope length and the erosion of the slopes can be reduced. The weight of the
trucks and dozers is used to compact the layers of waste rock material which increases
the geotechnical stability by reducing subsidence processes and the formation of
settlement cracks. Due to the fact that the permeability of the entire dump is reduced, the
amount of seepage water and oxygen intrusion are also decreased and thus the inner
erosion as well as the formation of acid mine drainage (AMD) are minimized.
AMD is caused by the oxidation of pyrite in the Chinh Bac waste dump which leads to the
release of heavy metals, salts and acidity into the surface and groundwater. In this regard
a reactive transport model was adapted to the Chinh Bac dump for the forecast of the
seepage water evolution and contaminant discharge from the waste dump. In order to
characterize the dump material with regard to its hydraulic, geotechnical, geochemical and
hydrogeological properties, several investigations were carried out: trial pit sampling,
development of a drilling program with drill core retrieval, sampling of water and solid
material, execution of lab and field experiments (e.g. density tests, infiltration tests,
pumping tests, chemical analyses).
These investigations showed that the waste dump is built up heterogeneously which was
also proven by the broad bandwidth of the investigated parameters (e.g. water contents,
grain size distributions, densities, porosities, water chemistry).
A long-term water and rock sampling campaign (see Figure 6) of the waste dump and its
surrounding open-cast mines, drilling and field/lab testing were undertaken as well as the
gathering of already existing data on the mining site history, meteorology and geography.
The assessed information (e.g. soil water content, grain size distributions, chemical
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
11
analyses etc.) was then used as input data for the geochemical model to predict the longterm contaminant discharge from the dump into the groundwater.
The geochemical model implements the principles of reaction kinetics, thermodynamics
and transport theory. The following processes are considered: water flow in variably
saturated porous media, diffusive gas transport in partial saturated pore systems,
advective-dispersive solute transport, interactions between dissolved species, solid
mineral phases and newly formed secondary phases and gaseous components as well as
the influence of the rainy season (May - October) and the relatively dry season (November
- April) on the percolation rates. The size of the model column is set to 130 m which is
assumed to be the approximate thickness of the unsaturated zone based on the
observations of the ground water level monitoring.
The geochemical model is able to simulate the acid generation due to the oxidation of
sulphide minerals, the release of acidity and contaminants from secondary mineral phases
(e.g. Jarosite, Melanterite), the neutralization/buffering of acidity due to the dissolution of
mineral phases such as carbonates, sheet silicates or iron- and aluminium hydroxides,
silicate weathering, generation of dissolved aquatic complexes and their influence on the
solubility of the participating species, the mobilization of heavy metals due to the
aforementioned processes and their retardation due to sorption and/or precipitation in
order to predict the water quality.
Figure 6:
Hydrochemical monitoring locations in the open pit area of Nui Beo
Coal Company (NBCC)
The geochemical modelling results showed that a long term contaminant discharge from
the Chinh Bac dump has to be expected. Contaminant concentrations (sulfate, heavy
metals) will be elevated over several hundred years so that an appropriate remediation of
the dump is paramount. Figure 7 shows the modelled evolution of the pH, sulfate and lead
12
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
concentrations in the seepage water at where the lysimeters are located (see Figure 6). In
this modelling exercise, a dump surface without any vegetation was assumed.
The modeling results predict that there will be an increased output of contaminants over
the next centuries which also cannot be adequately reduced solely by the provided
revegetation measures (model results not shown) of the Vietnamese project partners.
Figure 7:
Modelled evolution of pH-value, sulfate and lead concentration in the
seepage water at present state of the waste rock dump Chinh Bac
Unfortunately, due to the large dimensions of the dump, many reasonable and costefficient remediation options (e.g. coverage) cannot be implemented anymore. As a result
of the investigations, it was found that the combination of the construction of berms,
revegetation, catchment and diversion of dump surface water and water
catchment/treatment are feasible options in order to limit the impact of AMD on the
environment.
At the end, the project results outlined above transferred into the waste rock dump
stabilization decision support system (DSS) that was developed as a web application as
previously described for the mine dust control DSS. This DSS offers a best practice guide
(BPG) and Decision Support Tools (DST). The text-based BPG deals with the principles,
practices and cost-effective technologies for the construction and rehabilitation of waste
rock dumps. The quantitative assessment of the monitoring, classification and slope
stability issues are provided within the DST module. As already mentioned, the web-based
DSSs developed within the scope of the RAME project are available only for authorized
users.
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
13
CONCLUSION
Within the scope of the RAME sub-project IV “Dust Mitigation and Monitoring”, dust
emission factors for the mining activities identified at the NBCC mining area were derived
by dispersion modeling based on the real-time measurement data. Subsequently, dust
control methods were selected and reduction factors for these methods were determined
through real-time measurements followed by dispersion modeling and review of previous
studies, such as Countess Environmental [10] and NIOSH [17]). The overall dust emission
from the mining area as well as the performance of the selected dust control methods
were also investigated by dispersion modeling. Finally, a web-based DSS and a BPG as a
guidance document were developed to support the users to design cost-effective mine
dust control strategies.
The main outcomes achieved by the RAME sub-project IV are presented in detail in the
project final reports (BBK I [3]; Brenk Systemplanung [5] and CBM GmbH [7]). These
outcomes can be summarized as follows:

Location- and activity-specific mine dust emission and reduction factors can be
applied for other mining locations under similar mining features, control method
application conditions and climatic characteristics.

Dispersion modeling on the basis of the location- and activity-specific parameters
can be used to validate the distribution of mine dust emissions and the
effectiveness of proposed dust control approaches.

The DSS developed for mine dust control can provide reliable assessment for mine
dust emission levels and effectiveness of dust control approaches.
The RAME sub-project II “Dump Stabilization and Rehabilitation” started with the data
collection and analyses for the actual stability state of the waste rock dump area at the
NBCC mine. Based on these analyses, measures for waste rock dump stabilization and
rehabilitation (e.g., alternative dumping method) were developed and tested. Furthermore,
AMD reduction and long-term groundwater protection options were compared by water
quality prediction models. At the end, the project results were compiled into a web-based
DSS, including a BPG, aiming to assist in design and rehabilitation of waste dumps.
Comprehensive descriptions of the results of the RAME sub-project II are provided within
the respective final reports (BBK I [4] and Brenk Systemplanung [6]). Concerning these
results, the following issues can be drawn:

The proposed dumping method (layered dumping) can lead to significant economic,
environmental and stabilization benefits in comparison to the side-hill dumping.

AMD reduction and long-term groundwater protection alternatives can be accurately
evaluated by site investigations followed by geochemical modeling. It was shown by
geochemical modelling that contaminant discharge (lead, sulfate) into the
groundwater will occur for several centuries and cannot adequately be reduced
solely by revegetation measures. It was found that the construction of berms,
catchment and diversion of dump surface water and water catchment/treatment are
feasible options in order to limit the impact of AMD on the environment.

The DSS developed for waste rock dump stabilization can assist engineers during
planning, stabilization and rehabilitation of waste rock dumps.
As a future research, the solution approaches proposed by the RAME project for mine dust
control and waste rock dump rehabilitation would be validated at the mining areas having
14
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
similar mining, geological and climatic characteristics. Development of analogous solution
approaches for other mining locations by following the methodology described in the
RAME project would be another worthwhile future research possibility.
ACKNOWLEDMENTS
The RAME project partners, the Institute of Mining Engineering I and the Institute of
Geotechnical Engineering of the RWTH Aachen University, Brenk Systemplanung and
Gesellschaft für Consulting, Business and Management mbH (CBM) wish to gratefully
acknowledge the financial support provided by the German Federal Ministry of Education
and Research (BMBF). The project partners also acknowledge the help given by the
managers and engineers of the VINACOMIN and the NBCC in organization of the field
work.
LITERATURE
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
Ahmad, S.: Contribution to economical waste rock dumping by comparing traditional
sidehill fill disposal with layered dumping (Doctoral Dissertation). Aachen, Germany:
RWTH Aachen University, Institute of Mining Engineering I (BBK I), 2013.
Bai Chay Meteorological Station: Meteorological data. Ha Long, Vietnam, 2012.
BBK I: Schlussbericht (FKZ02WB1017) "Verbundprojekt: Bergbau und Umwelt
Vietnam, Unterverbund (UV IV): Staubverminderung und -monitoring. Teilprojekt (UV
IVa): Untersuchungen und Entwicklung von Konzepten zur Verminderung und zum
Monitoring von Staubemissionen entlang der Produktionskette "Entsorgung"",
Aachen, Germany: RWTH Aachen University, Institute of Mining Engineering I
(BBK I), 2013.
BBK I: Schlussbericht (FKZ02WB0964) „Verbundprojekt Bergbau und Umwelt
Vietnam, Unterverbund (UVII) Haldenstabilisierung und –sanierung, Teilprojekt (UV
IIa): Geotechnische Untersuchungen zur Entwicklung von Konzepten zur
nachhaltigen Sanierung von Abraumhalden". Schlussbericht, Bergbau und Umwelt in
Vietnam, Aachen, Germany: RWTH Aachen University, Institute of Mining
Engineering I (BBK I), 2013.
Brenk Systemplanung: Schlussbericht (FKZ02WB1019) "Verbundprojekt: Bergbau
und Umwelt Vietnam, Unterverbund (UV IV): Staubverminderung und -monitoring.
Teilprojekt (UV IVc): Standortmodell zur Staubausbreitung, Bewertung der
Wirksamkeit von Maßnahmen zur Staubreduzierung und Erarbeitung eines
Monitoringkonzeptes", Aachen, Germany: Brenk Systemplanung, 2013.
Brenk Systemplanung: Schlussbericht (FKZ02WB0965) „Verbundprojekt Bergbau
und Umwelt Vietnam, Unterverbund (UVII) Haldenstabilisierung und –
sanierung,Teilprojekt
(UV
IIb):Untersuchungen
zur
Sickerwasserbilanz,
Schadstoffaustrag und Haldenbränden". Aachen, Germany: Brenk Systemplanung,
2013.
CBM GmbH: Schlussbericht (FKZ02WB1018) "Verbundprojekt: Bergbau und Umwelt
Vietnam, Unterverbund (UV IV): Staubverminderung und -monitoring. Teilprojekt (UV
IVb): Untersuchungen und Entwicklung von Konzepten zur Verminderung und zum
Monitoring von Staubemissionen entlang der Produktionskette „Gewinnung"",
Aachen, Germany: CBM GmbH, 2013.
Chakraborty, M., Ahmad, M., Singh, R., Pal, D., Bandopadhyay, C., & Chaulya, S.:
Determination of the emission rate from various opencast mining operations.
Environmental Modelling & Software(17), pp. 467-480, 2002.
CostMine: Mine and Mill Equipment Costs: An Estimator's Guide. InfoMine USA, Inc.,
2009.
Martens et al.: Effective Mine Dust Control and Waste Rock Dump Rehabilitation: A Case Study
15
[10] Countess Environmental: Western Regional Air Partnership’s (WRAP) fugitive dust
handbook, prepared for Western Governors' Association. Westlake Village, CA, US,
2006.
[11] Environment Australia: Best practice environmental management in mining: Dust
control. Commonwealth of Australia, 1998.
[12] Environment Australia: National Pollutant Inventory (NPI): Emission estimation
technique manual for mining, Version 3.1 (first published in March 1999). Australian
Government, Deparment of Sustainability, Environment, Water, Population and
Communities, 2012.
[13] Foley, G., Cropley, S., & Giummarra, G.: Road dust control techniques, evaluation of
chemical dust suppressants' performance. Victoria, Australia: ARRB Transport
Research Ltd., 1996.
[14] Ghose, M. K.: Emission factors for the quantification of dust in Indian coal mines.
Journal of Scientific and Industrial Research, 63, 763-768, 2004.
[15] Landtag NRW: Gesetzentwurf der Landesregierung. Gesetz zur Änderung des
Wasserentnahmeentgeltgesetzes des Landes Nordrhein-Westfalen. Düsseldorf,
Germany: Landtag Nordrhein-Westfalen, 2012.
[16] MyGeo.info:
Retrieved
on
27.
01
2011
from
http://www.mygeo.info/landkarten/welt/a3_rl1w_politische_weltkarte_winkel_0.png,
nd.
[17] NIOSH: Dust control handbook for industrial minerals mining and processing, Report
of Investigations 9689. Pittsburgh, PA, US: The National Institute for Occupational
Safety and Health, 2012.
[18] Sinh, B.T.:Environmental policy and conflicting interests: Coal mining, tourism and
livehoods in Quang Ninh Province, Vietnam. In P. Hirsch, & C. Warren (Eds.), Politics
of the Environment in Southeast Asia, Resources and Resistance (pp. 159-180).
London, UK: Routledge, 1998.
[19] USEPA: Iron and steel plant open source fugitive emission control evaluation.
Research Triangle Park, NC, US: US Environmental Protection Agency, 1983.
[20] USEPA: Emissions Factors & AP 42. Compliation of Air Pollutant Emission Factors.
Section 11.9. Western Surface Coal Mining. Revised Final Report (5th ed., Vol. 1:
Stationary Point and Area Sources). US Environmental Protection Agency, 1998.
[21] USEPA: Emissions Factors & AP 42. Compliation of Air Pollutant Emission Factors.
Section 11.9. Western Surface Coal Mining. Final Section (5th ed., Vol. 1: Stationary
Point and Area Sources). US Environmental Protection Agency, 1998.
[22] USEPA: Emissions factors & AP 42. Compilation of air pollutant emission factors.
Section 13.2.2. Unpaved roads. Final section (5th ed., Vol. 1: Stationary point and
area sources). US Environmental Protection Agency, 2006.
[23] USGS: U.S. Geological Survey, 2007 Minerals Yearbook, Vietnam (Advanced
Release), 2009.
[24] Wikimedia
Foundation
Inc.:
Retrieved
on
27.
01
2011
from
http://upload.wikimedia.org/wikipedia/commons/archive/1/10/20060625141614!World
_map_blank_black_lines_4500px_monochrome.png, 2010.