2.3.4 groundwater/seepage management · the hydraulic design for the clean storm water diversion...
TRANSCRIPT
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 29
2.3.4 Groundwater/Seepage management
In order to protect the groundwater resource below and within the vicinity of the Discard
Dump, two mechanisms will be employed to manage seepage from the facility, i.e. an
under-drainage system and a liner.
2.3.4.1 Under-drainage system
The under drainage system is designed to collect seepage on top of the liner and to achieve
phreatic surface drawdown at the toe of the Discard Dump. As such, the under-drainage
system is strategically placed along the critical downstream toe line of the Discard Dump
and includes the following:
• A filter drain (6 m wide toe drain);
• Non-perforated (High Density Polyethylene) HDPE drainage outlet pipes reporting to
manholes; and
• A collector pipe (linking the manholes) that diverts the drainage flows to a
downstream collection sump from where the seepage is diverted to the PCD.
2.3.4.2 Discard Dump Liner
The proposed liner system for the Discard Dump generally complies with the Class C liner
type in the waste classification regulations published in Government Notice R. 634 in
Government Gazette No. 36784, dated 23 August 2013 (GNR634), in terms of the NEMWA.
The liner therefore comprises four layers, as shown in Figure 2.2:
• Layer D: This is a 150mm compacted layer of reworked in-situ soils with a minimum
thickness. The layer must be compacted to a minimum density of 95% Standard
Proctor maximum dry density at a moisture content of 0 to +2% of the optimum
moisture. The permeability of this layer should be lower than 1 x 10-9m/s;
• Layer C: This is a 150mm thick compacted clay layer. The layer must be compacted
to a minimum density of 95% Standard Proctor maximum dry density at a moisture
content of 0 to +2% of the optimum moisture content in layers not exceeding
200mm loose. The permeability of this layer should be lower than 1 x 10-9m/s;
• Layer B: This is a double textured 2mm thick HDPE geomembrane, which must be
laid in direct contact with the upper surface of compacted Layer C. In an effort to
withstand potential mechanical damage when the discard is placed, this
specification exceeds the Class C specification (the regulations require a minimum
of 1.5mm); and
• Layer A: This is a cushion layer of approximately 500mm thickness of fine to
medium sandy or similar suitable material, which is placed immediately above the
HDPE geomembrane to protect it from mechanical damage.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 30
Figure 2.2 Proposed Liner for the Discard Dump (Source: Geotail, 2014)
2.3.4.3 PCD Liner
The liner system for the PCD generally complies with the Class B liner type as described in
the waste regulation, GNR643. The liner comprises three layers, as shown in Figure 2.3:
• Layer C: This is a base preparation layer consisting of a compacted layer of
reworked in-situ soils with a minimum thickness of 150mm. The layer must be
compacted to a minimum density of 95% Standard Proctor maximum dry density at
a moisture content of 0 to +2% of the optimum moisture content. The permeability
of this layer should be lower than 1 x 10-9m/s;
• Layer B: A 450mm thick compacted clay layer. The layer must be compacted to a
minimum density of 95% Standard Proctor maximum dry density at a moisture
content of 0 to +2% of the optimum moisture content in layers not exceeding
200mm loose. The permeability of this layer should be lower than 1 x 10-9m/s;
• Layer A: A 1.5mm thick HDPE geomembrane, which must be laid in direct contact
with the upper surface of compacted Layer B;
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 31
Figure 2.3 Proposed Liner for the PCD (Source: Geotail, 2014)
2.3.5 Surface Water/Stormwater Management
The surface or stormwater management measures are designed to separate clean and dirty
water, divert clean water away from the Discard Dump and collect and contain water found
within the Discard Dump footprint, which is considered “dirty”.
2.3.5.1 Stormwater Diversion Channels
The hydraulic design for the clean storm water diversion system was undertaken by Ilanda
Water Services cc. (Ilanda) in June 2014 (refer to the “Kangra Pollution Control Dam and
Stormwater Channel Sizing Report” attached as Appendix C of the Design Report).
Based on the hydrological modelling undertaken (refer to Chapter 4 of the Ilanda report),
two channels are deemed necessary to divert clean stormwater away from the Discard
Dump, i.e. the North and South channel (refer to Figure 2.4).
A local watershed runs generally east west through the southern portion of Phase 2 (centre
compartment) of the Discard Dump. The two channels originate on this watershed. The
North Channel runs generally northwards while the South Channel runs southwards before
turning west and then northwest around the southern perimeter of the Discard Dump.
The proposed channels have been sized to comply with the GN704 requirements and as such
they are designed to convey the 50-year design flood peak (refer to the summary of the
channel sizing in Table 2.2). The catchments for the channels are relatively small.
Table 2.2 Stormwater Channel Dimensions
PARAMETER NORTH CHANNEL SOUTH CHANNEL
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 32
PARAMETER NORTH CHANNEL SOUTH CHANNEL
Catchment Size 32.9ha 4.9ha
Shape Trapezoidal Trapezoidal
Base width 1m 1m
Side slopes 1:1.5 (V:H) 1:1.5 (V:H)
Flow depth 0.83m 0.48m
Channel depth* 1.1m 0.8m
Max flow velocity** 3.7m/s 2.7m/s-
Flow type at max velocity Supercritical Supercritical
*Note: Channel depths are based on the flattest downstream portion of the channel
carrying the full design flow.
**Note: Flow velocities are based on the maximum longitudinal gradient.
The stormwater channels have been sized assuming unlined channels, and excavated into
the ground. The material excavated from the channel should be placed in a berm on the
downstream side of the channel. This serves two purposes:
• The berm will increase the capacity of the channel above its design capacity and
provide additional freeboard where required; and
• The berm allows cost effective construction as load and haul volumes are
minimised.
The berm should be compacted and vegetated. The channel should be kept free of long
grass, shrubs and woody vegetation.
It is good practice to allow a further 0.3m of freeboard in the channel. This is to allow for
wave action and flow surges in the channel. A summary of the channel sizes is presented in
Table 2.2 (previous page). In order to keep channel depths practical to construct, the
freeboard allowance within the channels are varied. Where freeboard within the channels is
less than 0.3m, the berms on the outsides of the channels provide the additional freeboard.
A minimum of 0.3m freeboard is therefore available in the channel.
The portion of the North Channel adjacent to Phase 1 and downstream of this will require
erosion protection. The flow regime is supercritical and design flow velocities are likely to
exceed 3.5m/s.
The South Channel will require erosion protection once it turns west and north-west.
Erosion protection could include concrete, HDPE, grouted stone pitching, Reno matrasses,
Armourflex or similar technology.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 33
Figure 2.4 Proposed Liner for the PCD (Source: Geotail, 2014)
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 34
2.3.5.2 Water Balance/Process Flow
A process flow diagram (PFD) (refer to Figure 2.5) was developed based on the information
provided in the design report (Appendix E) to depict the flow of water to and from the
proposed Discard Dump.
The Water Balance (WB) (refer to Figure 2.6) for the Discard Dump was compiled based on
the PFD. A simulation of water movement within the entire discard facility was conducted,
assuming that the facility has been filled and surfaces fully rehabilitated. Drain and storm
water inflows from the discard facility, direct rainfall on the surface of the PCD, limited
seepage through the lining and evaporation from the PCD surface were balanced.
The WB shows that 1 421 154m³ of water per annum would need to be pumped out of the
PCD to the Opencast Pit East in order to operate the PCD as empty and maintain sufficient
capacity for the 1:50 year storm event.
Figure 2.5 Discard Dump Process Flow Diagram
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 35
Figure 2.6 Discard Dump Water Balance
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 36
2.3.5.3 Discard Dump Design Features
The Discard Dump has been designed to avoid storage of water on the facility, thereby
increasing its stability.
The side slopes will be terraced and berm penstocks will be utilised to drain the permanent
benches. This water will be captured by the catchment paddocks, which will be located at
ground level. The run off will be diverted to the PCD.
It is recommended that the Discard Dump is operated with the minimum of water stored on
the top surface at all times.
2.3.5.4 Pollution Control Dams
The calculations for the sizing of the PCD was also undertaken by Ilanda and the
methodology for the modelling undertaken is provided in the Ilanga report (June 2014)
attached as Appendix C of the Design Report (Appendix E of this document).
The PCD will serve to collect and contain direct rainfall, runoff from the Discard Dump
surface and the “dirty water catchment” of the Discard Dump, as well as seepage captured
by the under-drainage system (within the catchment paddocks). The stormwater diversion
channels (refer to section 2.2.5.1 above) will divert clean water away from the “dirty” area
in order to reduce the amount of polluted water which must be contained, thereby
reducing the PCD capacity requirement.
The proposed maximum capacity of the PCD is 100 000m³. This capacity will be sufficient
provided that:
• Concurrent rehabilitation is undertaken: The Discard Dump has been designed in a
manner that provides for three development phases and concurrent rehabilitation.
Once rehabilitation is undertaken, the rehabilitated area is considered clean and
runoff from that area can be released to the environment. This reduces the volume
of water that needs to be captured and contained. Based on the Discard Dump’s
modular design, and the assumption that rehabilitation will be concurrent, the PCD
has been sized to service an area equivalent to one phase/compartment of the
Discard Dump. Should rehabilitation not be truly concurrent, a second, or even
third PCD may be required;
• Water is pumped out of the PCD: A return pumping capacity of 200m³ of water per
day is required in order to maintain the dam’s freeboard and capacity to
accommodate the 50 year design storm. If no water is returned from the PCD, it
will act as an evaporation dam, thereby requiring a 1.45Mm³ PCD with an average
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 37
depth of 2m. The full pump capacity for the PCD (200m³/day) will be used about
45% of the time (168 days a year on average). [In order to reduce the size of the
PCD to the minimum, i.e. able to accommodate only the 1:50 storm event, the PCD
would have to be emptied every day].
The PCD design specifications are provided in Table 2.3
Table 2.3 PCD Design Specifications
DESCRIPTION VALUE
Maximum capacity 100 000m³
Maximum water depth 4.2m
Dry freeboard 0.8m
Maximum embankment height < 5m
Crest width 5.0m
Upstream slope angle 1(v):2.5(h)
Downstream slope angle 1(v):2.5(h)
Box cut depth varies
Box cut base compaction standard
95% Standard Proctor density
Fill compaction standard 100% Standard Proctor density at 0 to +2% of the optimum moisture content in layers not exceeding 200mm loose
Liner system Refer to section 2.2.4.3 of this report
The water pumped out of the PCD will be sent to the washing plant, before being pumped
to Pit D East where it will be evaporated. The management of this water once it is pumped
out forms part of the scope of the mine-wide water management, therefore this is not
discussed in detail in this document, which is limited to the management of the proposed
Discard Dump.
2.3.6 Safety Classification
The safety classification was undertaken by Geotail (refer to section 4.3 of the Design
Report).
The safety classification allows for the development of a management system that is
tailored to suit the needs of the particular residue deposit, rather than imposing a one-size
fits all system that, of necessity, must cater for the most severe hazards and risks.
The safety classification undertaken defines the potential consequences of a failure of the
Discard Dump. The hazard rating is not associated with the risk (likelihood of adverse
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 38
impacts), which can be reduced and minimised through the implementation of risk
management techniques.
The South African Code of Practice for Mine Residue (SANS 0286:1998) will be utilised for
classification purposes. SANS 0286:1998 calls for a safety classification to differentiate
between residue deposits of high, medium and low hazard rating on the basis of their
potential to cause harm to life or property within the zone of influence. The classification
should be based on the anticipated configuration of the storage facility at the end of its
design life.
The overall hazard rating of the Discard Dump is “low” as shown in Table 2.4.
Table 2.4 Discard Dump Safety Classification
DESCRIPTION ZONE OF INFLUENCE HAZARD RATING
Number of residents in zone of influence
Not aware of any residents within zone of influence (Discard Dump is located within an existing mining
area).
Low
Number of workers in zone of influence
Only mine workers within zone Low
Value of third party property zone of influence
Value of third party property not significant Low
Depth to underground mine workings
The Discard Dump footprint is not undermined. Low
2.3.7 Access Control
A boundary fence will be erected around the perimeter of the Discard Dump facility to keep
out livestock and discourage entry by people.
A haul road will be constructed around the Discard Dump. This haul road will connect to the
existing haul road to the east of the proposed Discard dump Complex. The internal haul
road will also lead to the PCD. The haul roads within the Discard Dump Complex will not
exceed a width of 8m.
2.4 Discard Dump Rehabilitation
Concurrent rehabilitation is required for the effective management of environmental
impacts. Rehabilitation will comprise of correctly contouring the side to a final side slope
angle of 1(v):3(h) and giving the Discard Dump an overall slope of 1(v):4(h).
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 39
It is recommended that Discard Dump is constructed in accordance with the cover
specifications provided in the “Minimum Requirements for Waste Disposal by Landfill”
(1998). Figure 2.7 depicts the proposed soil cover, which has been adapted from the
Minimum Requirements (Figure A.8.12, Appendix A of the Minimum Requirements). The
following layers are proposed:
• V layer: A 450mm thick layer of selected material. The soil used should have a
Plasticity Index (PI) of between 5 and 15 and a maximum particle size of 25mm.
The soil should be compacted to achieve an in situ permeability of 0.5m per year,
as measured using a double ring infiltrometer test. The compaction standard should
be at least 85% of the maximum Standard Proctor dry density at +2% of optimum
moisture content in layers not exceeding 200 mm loose; and
• U Layer: A 200mm thick layer of topsoil planted with local grasses and shrubs. The
layer must be lightly compacted after spreading.
Figure 2.7 Proposed Cover for the PCD (Source: Geotail, 2014)
It is recommended that the topsoil removed during construction (approximately 400mm
thickness) is placed in dedicated stockpiles for use in rehabilitation.
In order to reduce the PCD capacity requirements, it is important that rehabilitation is
undertaken within the specified timeframes, i.e. the rehabilitation of one compartment
should be close to completion by the time construction of the next compartment begins.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 40
3 PROJECT ALTERNATIVES
The consideration of alternatives for the proposed development during the environmental
investigation, is required in terms of the NEMA, MPRDA and NWA processes. The developer
should be encouraged to consider alternatives that would meet the objective of the original
proposal and which could have an “acceptable” impact on the environment. The role of
alternatives in the EIA process is to therefore find the most effective way of meeting the
need and purpose of the proposed development, through reducing or avoiding potentially
significant negative impacts and enhancing the environmental benefits of the proposed
activity as far as possible.
3.1 Activity/Project
Three options were considered to accommodate the additional discard, i.e. the expansion
of the current Maquasa East Discard Dump, the no-go alternative, and the construction of a
new disposal facility.
3.1.1 Expansion of existing Maquasa East Discard Dump
The existing Maquasa East Discard Dump is located to the north-west of the coal washing
plant (refer to the centre of Figure 3.1).
According to the Maquasa West 2009 EMPr Amendment, the existing discard facility, has a
maximum calculated capacity of 12 000 000 tonnes (this estimate is currently being
confirmed through an assessment of the dump).
The current boundary of the existing discard dump is less than 500m from boundary fence
which separates the mining area from the Driefontein community.
The expansion of the dump was not considered feasible because the available area would
provide sufficient capacity for the additional discard disposal required for the extended
LoM for the Kangra Coal operations and the proposed Kusipongo expansion.
3.1.2 Development of a New Discard Dump (Preferred Option)
This option was identified as the preferred alternative due to fact that the current discard
dump could not be sufficiently expanded. In order to implement this option, a location
needed to be selected (refer to the discussion under Section 3.2 below) and the disposal
method (refer to section 3.3 below).
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 41
Figure 3.1 Existing Discard Dump
[REFER TO A3 FIGURE UNDER APPENDIX A]
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 42
3.2 Alternative Locations for New Discard Dump
Six (6) potential sites were identified by Hatch during their 2011 Concept Study (refer to
Appendix D), which included an assessment of the sites as well as the potential disposal
methods. The following sites were assessed (refer to the locality map under Figure 3.2):
• Site A: situated to the east of the coal washing plant;
• Site B: situated to the north of the coal washing plant;
• Site C: situated to the north west of the coal washing plant and includes the
existing Maquasa East Discard Dump site;
• Site D: situated to the west of the current wash plant position and is located on the
coal reserves in the area known as Maquasa West;
• Site E: opencast excavation situated approximately 2.4km to the west of the
current wash plant position in the Maquasa West Open Cast section; and
• Site F: The site is situated approximately 3.2km to the west of the current wash
plant position.
A fatal flaw assessment was undertaken by Hatch (now Hatch Goba) in 2011. According to
the assessment, “fatal flaws” are those factors which eliminate the use of the sites for
discard disposal because they do not adhere to the environmental and/or safety objectives
(Hatch, 2011). The fatal flaw assessment table extracted from the Site Selection Report is
presented in Table 3.1 below. This table shows that Site E was eliminated due to the
potential difficulty of controlling the Acid Mine Drainage (AMD) in the open cast excavation
Table 3.1 Fatal Flaw Assessment of Potential Sites (Hatch 2011)
SITE FATAL FLAW COMMENT
A No No Comment
B No Steep zone
C No Above old mined out area including existing Discard Dump
D No Acid Mine Drainage (AMD) could exclude this site
E Yes Unlikely to be able to control AMD and opencast operation not guaranteed
F No No comment
The remaining sites were ranked subjectively by considering:
• Safety classification;
• Environmental classification;
• Design and operation; and
• Economics.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 43
Critical factors were then weighted out of 10, with 1 having the least important and 10
being of critical importance. According to the Site Selection Report, “Critical Factors” are
those factors that do not adhere to the environmental and/or safety objectives, but can
effectively be mitigated by engineering solutions (Hatch, 2011).
Although Site C was identified as the preferred site in the Site Selection Report, Kangra
rejected this site due to the fact that it is located above an old mined out area. Site F as
therefore selected as the preferred site. The advantages and disadvantages of each site are
presented in Table 3.2.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 44
Figure 3.2 Potential Discard Dump Locations
[FIGURE NOT TO SCALE]
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 45
Table 3.2 Assessment of Alternative Sites
SITE ID ADVANTAGES DISADVANTAGES
Site A
• The relatively flat topography.
• The close proximity (±0.2 km) to the proposed plant position.
• The dump cannot sterilise any coal reserves.
• The close proximity (± 0.6 km) to the Heyshope Dam.
• The collected seepage must be handled by a pumping system that must operate after mine closure.
• The visible impact of the dump.
• The polluted surface water and storm water runoff must be handled by a pumping system during operation.
Site B
• The close proximity (± 0.5 km) to the proposed plant.
• The dump can blend in with the natural topography to reduce the visible impact.
• The polluted surface water and storm water run-off can be handled by a gravity system (passive).
• The seepage can be handled by a gravity system (passive).
• The major seep zone that will require significant engineering design to overcome, and will have a low confidence level of success.
• The site is located partially above the old mined out area and the correct as mined out survey should be sourced to establish how many pillars have been left after mining activities stopped.
• The depth to underground workings is approximately 30 m.
Site C
• The dump can blend in with the natural topography to reduce the visible impact.
• The polluted surface water and storm water run-off be handled by a gravity system (passive).
• The seepage can be handled by a gravity system (passive).
• That it is (± 1.2 km) from the existing washing area.
• The site is located directly above the old mined out area and the correct as mined out survey should be sourced to establish how many pillars have been left after mining activities stopped.
Site D
• The dump can blend in with the natural topography to reduce the visible impact.
• The polluted surface water and storm water runoff can be handled by a gravity system (passive).
• The seepage can be handled by a gravity system (passive).
• The difficulty in containing seepage.
• The distance (± 1.9 km) from the plant position.
• The site is located partially above the old mined out area and the correct as mined out survey should be sourced to establish how many pillars have been left after mining activities stopped.
Site F (Preferred Option)
• The dump is on a slope which faces away from the Heyshope dam and Driefontein and therefore the visual impact is reduced.
• The two naturally occurring clay layers within the soil profile, and the elevation of the ground water is below the second layer.
• The dump cannot sterilise any coal reserves.
• The distance from the current washing plant position (3.2km).
• The introduction of a pumping system to, return the seepage to the plant during the operational life.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 46
3.3 Disposal Alternatives
Four disposal alternatives were considered during the 2011 Concept Study (refer to
Appendix D).
3.3.1 Integrated Discard “Dry” (Preferred Alternative)
Integrated discard “dry” process involves dumping coarse discard material the conventional
way in layers and mixing the low moisture “filter cake” fine discard material in layers with
the coarse discard.
The integrated discard “dry” technique will reduce the permeability of the coarse discard
and therefore a have a reduction in AMD. Although the expected AMD is significantly less
than that for co-disposal AMD is expected to continue after closure.
3.3.2 Co-disposal “Wet and Dry”
Co-disposal involves the impoundment of slurry within the body of the coarse discard,
which will lead to AMD during the operating life and a considerable period after closure.
3.3.3 Integrated Discard “Wet”
Integrated discard involves the mixing of slurry and the coarse discard which will be
deposited like conventional tailings. The tailings will beach, with the coarse product being
deposited first followed by the fine product which will accumulate at the pool centre.
The integrated discard technique will reduce the permeability of the coarse discard and
therefore a reduction in AMD is expected. Although the expected AMD is significantly less
than that for co-disposal, AMD is expected to continue after closure. However, this disposal
technique is relatively new and unproven technology.
3.3.4 Separate Disposal ”Wet – Site 1 and Dry Site 2”
Separate disposal involves the deposition of the slurry into the underground workings or a
separate above ground fines slurry pond, and the impoundment of the coarse discard above
the ground surface. This reduces the AMD potential of the coarse discard, and the control
and containment of AMD from the slurry if it is placed below ground.
In the case of Maquasa the fines could be transported and deposited in the form of a slurry
back into the underground workings. These areas of disposal would be prepared using the
appropriate preplanning and mining methods.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 47
The slurry would then be deposited at an elevation below the expected working level and
remains flooded thereby excluding or limiting the supply of oxygen. However, a decision
has been made to stop this operation and to dry the slurry and dispose of the “filter cake”
on the coarse discard dump.
Coarse Discard disposal involves impounding the coarse discard on a selected site above
natural ground. The coarse discard is then compacted to minimise the risk of spontaneous
combustion by limiting the ingress of air and water into the waste dump. The AMD that
could be generated from the coarse discard during operations would then be captured and
contained within the mine property and once the dump has been encapsulated, the amount
of seepage is likely to cease after a short period of time.
3.4 Land Use Alternatives
It is important to consider if there are any viable alternative uses of the land over which
the development is proposed. It must be noted that the proposed development area is
located within an existing mining right area (MRA), on land owned by the applicant.
3.4.1 Tourism
The proposed Discard Dump area is located within an existing MRA, adjacent to a
rehabilitated opencast pit and to the north-east of the Maquasa West current and proposed
pits. The use of this land for tourism is therefore not feasible.
3.4.2 Residential
As discussed above, the proposed Discard Dump area is located within an existing MRA, in
close proximity to the existing and proposed opencast pits of Maquasa East and West. The
surrounding land uses therefore precludes the use of this land for residential developments.
3.4.3 Grazing of Cultivated Land
The location of the proposed Discard Dump within a MRA, immediately adjacent to the
rehabilitated Maquasa East Pit D. This makes the discard dump area unsuitable for use as
grazing and cultivated land unfeasible during the LoM.
3.4.4 Mining
No viable ore reserves are located beneath the proposed Discard Dump site therefore the
used of the area for mining is not possible.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 48
3.5 No Go Alternative
This alternative would prevent the proposed expansions from being implemented, as there
would be no facility for the disposal of additional discard. This in turn would shorten the
LoM and prevent the exploitation of important coal resources and the retention of
employment in the long term.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 49
4 ENVIRONMENTAL BASELINE DESCRIPTION
This chapter comprises a description of the current, or baseline environmental, socio-
economic conditions of the proposed Discard Dump area, which is referred to here as the
“Study area”. Specialist studies were conducted over the extent of the proposed Discard
Dump area. Where appropriate, information has been extracted from the specialist studies
undertaken for the previously proposed Power Station and Ash Dump (not constructed),
which would have covered what is now the southern half of the study area (refer to Figure
4.14).
4.1 Climate
The study area lies at an average altitude of approximately 1430m. It is located in the
South African Highveld sub-humid climatic zone, which is a warm, mild summer rainfall
region. It is characterised by warm, wet summers and cool, dry winters.
4.1.1 Temperature
Daily summer (December to January) temperatures range between 15 - 27°C. Winter (June
to August) temperatures range between 3 - 17°C. The humidity is higher during the summer
months, ranging between an average of 80% during November and 65% during June.
4.1.2 Wind
The prevailing wind direction is north, northwest during the summer months with a slight
change to north east during the months of February to April.
The Piet Retief area experiences calms less than 1% of the time, and experiences very high
wind speeds (>0.8m/s) very infrequently.
4.1.3 Rainfall
The proposed Discard Dump is located in a summer rainfall area, with almost 84% of the
annual rainfall falling between the beginning of October and the end of March.
Rainfall data for the area was obtained from the Computing Centre for Water Research,
Natal University (CCWR) database. Gauge number 0407639 (Groot Rietvlei) was used, which
provided daily records starting on 1 July 1929 and ending on 31 August 2000, i.e.71 years
long. The gauge is located approximately 12.2km south of Kangra.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 50
This data was analysed to produce the average monthly rainfall and average rainfall days
figures presented in Table 4.1 (refer to Ilanda Services Report attached as Appendix C of
the Design Report attached under Appendix E of this EIR).
Table 4.1 Summary of rainfall data (Ilanda, June 2014)
MONTH AVERAGE RAINFALL (MM) AVERAGE RAINFALL DAYS
October 76.4 5.8
November 117.3 8.3
December 132.5 8.5
January 132.1 8.2
February 107.4 6.9
March 83.1 5.7
April 47.6 3.6
May 19.1 1.7
June 7.0 0.9
July 10.2 0.8
August 10.7 1.2
September 30.5 2.6
Total Rain days 54.2
Mean Annual Precipitation 772.1mm*
*Note that the mean annual precipitation will not necessarily equal the sum of the
monthly averages
4.1.4 Evaporation
The mean annual evaporation (MAE) is approximately 1 400mm according to the data
obtained from the WR2005 database for the W51B quaternary catchment (Middleton et al,
2009) (refer to Table 4.2).
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 51
Table 4.2 Summary of monthly evaporation data (Ilanda, June 2014)
MONTH POTENTIAL EVAPORATION DEPTH (MM/MONTH)
January 153.7
February 131.5
March 127.3
April 99.0
May 82.3
June 69.2
July 77.6
August 100.1
September 127.0
October 137.1
November 142.7
December 152.7
Total 1 400mm/year
4.2 Geology
The information in this section is extracted from the Hydrogeological Investigation Report
compiled in respect of the proposed Discard Dump (refer to Appendix C-6).
4.2.1 Regional Geology
All of the known coal deposits in South Africa are hosted in sedimentary rocks of the Karoo
Basin, a large retro foreland basin, which developed on the Kaapvaal Craton and filled
between the Late Carboniferous and Middle Jurassic periods. The Karoo Supergroup is
lithostratigraphically subdivided into the Dwyka, Ecca, and Beaufort groups, succeeded by
the Molteno, Elliot, Clarens, and Drakensburg formations. The coal range in age from early
Permian (Ecca Group) through to Late Triassic (Molteno Formation) and are predominantly
bituminous to anthracite in rank, which is classification in terms of metamorphism under
influence of temperature and pressure.
Within the Karoo Basin, nineteen coalfields have been defined based on variations in
sedimentation, origin, formation, distribution and quality of the coals. These variations are
in tern related to specific conditions of deposition and the local tectonic history of each
area.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 52
4.2.2 Local Geology
The local geology of the study area is presented in Figure 4.1. The study area is located in
the Ermelo Coalfield, historically one of the most important coal producing areas of South
Africa. The Karoo Supergroup succession in the Ermelo Coalfield consists of the Dwyka
Group diamictites, which occur unconformably above a pre-Karoo basement which is
overlain by the coal bearing Vryheid Formation (Ecca Group); the basal Pietermaritzburg
formation of the Ecca Group not being present. The Vryheid Formation strata consist of five
(5) coal seams, namely A (at the base) – E Seams (Cairncross, 1986); of which all five (5)
seams is hosted by the Ermelo Coalfield coal seams.
Numerous Jurassic age dolerite dykes and sills intrude the Vryheid Formation at various
stratigraphic levels, which tends to influence the stratigraphy and coal qualities in places.
The geochemical environment is fundamentally dictated by the mineralogy of the various
lithological units. In general, the area has been divided into two (2) lithological units:
• arenite – siliciclastic coal-bearing rocks of the Eccca Group (and probably the
Vryheid Formation).
• dolerite – late-stage igneous rock which has been emplaced into the sedimentary
rocks.
Although the proposed development is situated within the Ermelo Coalfield, the coal seams
of interest has been logged as the Utrecht Coalfield seams of Gus and Dundas. The Gus
seam lies stratigraphically above the Dundas seam with a parting of ~15 to 20m. The Gus
seam occurs at a depth of approximately 100m from the surface, with an average width of
~1 to 2 m, whilst the Dundas seam occurs at a depth of approximately 45m from surface,
with varying thickness.
The surface geology in the study area is characterised by the development of a variable
thickness of unconsolidated overburden consisting of both transported and in-situ
weathering material.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 53
Figure 4.1 Geological Map of the Study Area
[REFER TO A3 FIGURE UNDER APPENDIX A]
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 54
4.2.3 Structural Geology
During the deposits of sediments in the still sagging basin, tension in the crust due to
continuing sagging led to failure and subsequently intrusion of the Post-Karoo dolerite sills
and dykes along week zones (e.g. fault/fracture zones). Consequently dykes and sills
varying between a few centimetres to a couple of metres in thickness intruded.
The highest topographic features comprise resistant remnants of the B4 and B6 dolerite
sills. The B4 sill basically lies concordant to sedimentation at the base of the Volksrust
Formation. Contrasting to the B4 sill, the B6 sill is highly transgressively active and creating
complex ring dyke structures that transgress the coal, causing vertical displacement and
areas of burnt or devolatilised coal.
Although no regional structural features are located within proximity of and / or traversing
the study area, site-specific geophysical data (GCS, 2009) indicates a number of inferred
structural features (interpreted as dolerite dykes) to traverse the study area.
4.3 Topography
The regional topography can be described as undulating with elevations ranging from 1750
metres above mean sea level (mamsl) in the highest regions to the south-east of the mining
operations in the south-eastern corner of the remainder portion of the farm Kransbank, to
1300 mamsl at the lowest point of the Heyshope Dam to the south-east of the Maquasa East
operations.
The Maquasa East and West mining operations are located on the eastern facing slopes of
the Heyshope Dam valley with elevations ranging from 1545 to 1305 mamsl with an average
gradient of 1:19 in an easterly direction.
The proposed Discard Dump site is topographically flat with a slight slope in a westerly
direction (i.e. towards the Egude River) at 4.9%. The topography of the project area is
presented in Figure 4.2.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 55
Figure 4.2 Topographical Map of the Study Area
[REFER TO A3 FIGURE UNDER APPENDIX A]
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 56
4.4 Soils, Land Use and Land Capability
A Soils, Land Use and Land Capability Assessment was undertaken by GCS (July 2014). The
information in this section is extracted from this report, which is attached under Appendix
C-1.
4.4.1 Soil forms
A total area of 106ha was surveyed during the soil assessment (refer to Figure 4.3). The
soils identified in the soil survey area are fairly uniform, with variations dependant largely
on degree of wetness in the lowermost horizon.
Four (4) soil forms were identified with the project area (refer to Figure 4.3), i.e. the
Pinedene, Clovelly and Glencoe forms, as well as an Anthrosol (this is a soil whose horizons
have been largely affected by human activity).
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 57
Figure 4.3 Soil forms within the Study Area
[REFER TO REPORT UNDER APPENDIX C-1]
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 58
Pindene (43.53ha of the study area)
The Pinedene (Pn) soil form is characterised by an Orthic A horizon, over a yellow-brown
Apedal B horizon, over an unspecified subsoil horizon with signs of wetness. Generally, the
Orthic A horizon has a slight red colour, which is a result of iron oxides (Fe) that
accumulate through weathering (Fey et al., 2010). Within the Pinedene soils found at the
proposed discard facility site, redox conditions have removed all hematite, forming a
yellow-brown colour in the A-horizon. Signs of wetness were identified in the lowermost
horizon.
Owing to a rocky lowermost horizon in places, it was difficult to dig auger holes to a depth
of greater than 1m. The Pinedene soil form was observed in the southern part of the study
area, as seen in Figure 4.3.
Clovelly (40.79ha of the study area)
The Clovelly (Cv) soil form has similar characteristics to the Pinedene soil form - the main
difference is that the Pinedene soil form comprises unspecified material with signs of
wetness below the B horizon, while the Clovelly soil form comprises unspecified material
below the B horizon. This soil varied in depth between 0.5 and 0.8m at the site.
Glencoe (17.06ha of the study area)
The Glencoe soil form is characterised by an Orthic A horizon, over a yellow-brown apedal B
horizon, over a hard plinthic subsoil horizon. Plinthate formation is commonly associated
with areas that are warm, with a humid climate and a distinct dry season.
The yellow-brown colour is attained through soil enrichment with iron oxides where
reduction and mobilisation of iron and its migration re-precipitate as mottles, nodules,
concretions and vesicular hardpan. Owing to a hard lowermost horizon in the area,
dominated by the Glencoe soil form, it was difficult to dig auger holes to a depth of greater
than 0.3m. The Glencoe soil form was observed in the mid-western part of the study area.
Anthrosol (4.62ha of the study area)
Anthrosols are soils formed through the effects of human activity, largely because these
soils have had their natural mantle converted or destroyed and the soils used to replace
these soils are anthropogenic soils. In South Africa, such soils are encountered on
rehabilitated areas, especially where open-cast mining methods have been employed,
mainly in coal mining activities in the Mpumalanga province (Martin, 2010).
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 59
The horizons that constitute one of the Anthrosols found are shown in Figure 4.6 of the Soils
Report. Anthrosols were observed in the area in which rehabilitation is taking place.
4.4.2 Current Land Use
The study area comprises of two land uses (refer to Figure 4.4):
• Land that is currently under rehabilitation (4.60ha of the total 106ha study area);
and
• Grassland (Themeda triandra, also known as Redgrass) currently used for cattle
grazing (97.6ha), which has scattered patches of bare soil.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 60
Figure 4.4 Current Land Use of the Study Area
[REFER TO REPORT UNDER APPENDIX C-1]
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 61
4.4.3 Land Capability
Land Capability can be described as “the fitness of a given tract of land to sustain a defined
use; differences in the degree of capability are determined by the present state of
associated attributes of the area in question” (Schoeman et al., 2002). Land Capability
generally refers to the ability of given soil and contextual conditions to sustain productive
agricultural cultivation.
The following three Land Capability classes determined by Schoeman et al. (2002) were
assigned to the study area based on the soil classifications of the area (refer to Figure 4.5):
• Intensive Agriculture (84.22ha): Most of the study area is covered by Clovelly and
Pinedene soil forms, classified as Class II - arable land (highlighted in pink in Table
4.3). These soils can be used for intensive agriculture. These soils are major
agricultural soil forms in South Africa, owing to their deep, well-drained nature.
• Moderate Agriculture (17.06ha): The study area also comprises soils of the
Glencoe form, which are poorly drained owing to their moderately slow
permeability in the upper parts of the soil (Horizon A). This has an influence on
their high water holding capacity (James, 1986). These soils are suitable for
moderate agriculture owing to their high management requirements, as they
exhibit a seasonal water table or ponding. These were thus classified as Class III, as
highlighted in green in Table 4.3. These soils tend to compact and form clods when
worked while they are still wet (James, 1986).
• Undefined Use (4.62ha): The study area also comprises an area under
rehabilitation, comprising Anthrosols. These soils do not have a defined capability
owing to the mixed and unknown composition of these soil types. In this case this
area will initially be grassed once rehabilitation is completed.
Table 4.3 Land Capability Classes- Description and Suitability
CLASS DEFINITION CONSERVATION NEED USE SUITABILITY
I • No or few limitations.
• Very high arable potential.
• Very low erosion hazard.
Good agronomic practice. Annual cropping.
II • Slight limitations.
• High arable potential.
• Low erosion hazard.
Adequate run-off control
Annual cropping with special tillage or ley (25
%).
III • Moderate limitations.
• Some erosion hazards.
Special conservation practice and tillage
methods.
Rotation of crops and ley (50 %).
IV • Severe limitations.
• Low arable potential.
• High erosion hazard.
Intensive conservation practice.
Long term leys (75 %).
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 62
CLASS DEFINITION CONSERVATION NEED USE SUITABILITY
V • Watercourse and land with wetness limitations.
Protection and control of water table
Improved pastures or Wildlife
VI • Limitations preclude cultivation.
• Suitable for perennial vegetation.
Protection measures for establishment e.g. Sod-
seeding
Veld and/or afforestation
VII • Very severe limitations.
• Suitable only for natural vegetation.
Adequate management for natural vegetation.
Natural veld grazing and afforestation.
VIII • Extremely severe limitations.
• Not suitable for grazing or afforestation.
Total protection from agriculture.
Wildlife.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 63
Figure 4.5 Land Capability of the Study Area
[REFER TO REPORT UNDER APPENDIX C-1]
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 64
4.5 Terrestrial Ecology (Flora and Fauna)
The information in this section has been extracted from the Ecological Assessment (GCS,
April 2015) and Avifaunal Assessment (GCS, February 2015), which are attached under
Appendix C-4 and C-5 respectively.
During the Scoping Phase, it was highlighted by BirdLife South Africa that the proposed
Discard Dump is located within an Important Bird and Biodiversity Area (IBA). The
MDARDLEA therefore requested that a separate avifaunal assessment is undertaken. The
information pertaining to avifauna is under a separate sub-heading in this section.
4.5.1 Vegetation Unit
The study area is comprised entirely of the Eastern Highveld Grassland (GM12) vegetation
unit (refer to Figure 4.6). To the south-west of the study area, a small portion of the mining
area is covered by the Wakkerstroom Montane Grassland vegetation unit.
The Eastern Highveld Grassland vegetation unit is distributed along slightly, to moderately
undulating plains, including some low hills and pan depressions in the Mpumalanga and
Gauteng Provinces. The vegetation is short, dense, grassland dominated by the usual
Highveld grass composition (Aristida, Digitaria, Erigrostis, Themeda, Tristachya, etc.) and
small, scattered rocky outcrops with wiry, sour grasses and some woody species (Acacia
caffra, Celtis Africana, Diospyros lyciodes subsp lycioides, Parinari capensis, Protea caffra,
P. welwitschii and Rhus magalismontanum).
The important taxa associated with this vegetation unit are:
• Graminoids: Aristida aequiglumis (d), A. congesta (d), A. junciformis subsp.
galpinii (d), D. tricholaenoides (d), Elionurus muticus (d), Eragrostis chloromelas
(d), E. curvula (d), E. plana (d), E. racemosa (d), E. sclerantha (d), Heteropogon
contortus (d), Loudetia simplex (d), Setaria sphacelata (d), Sporobolus africanus
(d), S. pectinatus (d), Themeda triandra (d), Trachypogon spicatus (d), Tristachya
leucothrix (d), T. rehmannii (d), Alloteropsis semialata subsp. eckloniana,
Andropogon, appendiculatus, A. schirensis, Bewsia biflora, Ctenium concinnum,
Diheteropogon amplectens, Eragrostis capensis, E. gummiflua, E. patentissima,
Harpochloa falx, Panicum natalense, rendlia altera, Schizachyrium sanguineum,
Setaria nigrirostris, Urelytrum agropyroides.
• Herbs: Berkheya setifera (d), Haplocarpha scaposa (d), Justicia anagalloides (d),
Pelargonium luridum (d), Acalypha angustata, Chamaecrista mimosoides, Dicoma
anomala, Euryops gilfillanii, E. transvaalensis subsp. setilobus, Helichrysum
aureonitens, H. caespititum, H. callicomum, H. oreophilum, H. rugulosum,
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 65
Ipomoea crassipes, Pentanisia prunelloides subsp. latifolia, Selago densiflora,
Sencio coronatus, Vernonia oligocephala, Wahlenbergia undulate.
• Geophytic Herbs: Gladiolus crassifolius, Haemanthus humilis subsp. hirsutus,
Hypoxis rigidula var.pilosissima, Ledebouria ovatfolia.
• Succulent Herb: Aloe ecklonis.
• Low Shrubs: Anthospermum rigidum subsp. pumilum, Stoebe plumose.
The Eastern Highveld Grassland is an ‘Endangered’ vegetation type and only small fractions
are conserved in statutory reserves. Some 44% is already transformed by cultivation,
plantations, mines, urbanisation, and by the building of dams. Cultivation may have had a
more extensive impact, than indicated by land cover data. The Endangered status of this
vegetation type warrants a medium-high environmental sensitivity. The species previously
listed are regarded representative of the Eastern Highveld Grassland vegetation type.
The diversity of plants within the study area represents 56 plant families, typically
dominated by Poaceae (graminoids), comprising 29 species (15.3%) and Asteraceae (Daisy
family), comprising 28 species (14.7%).
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 66
Figure 4.6 Vegetation Units within the Study Area
[REFER TO REPORT UNDER APPENDIX C-4]
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 67
4.5.2 Declared Conservation Areas
The conservation status of the Eastern Highveld Grassland vegetation is listed as
Endangered. This vegetation type has a conservation target of 24%. Currently only a small
fraction is conserved in statutory reserves (Nooitgedacht Dam and Jericho Dam Nature
Reserves) and in private reserves (Holkranse, Kransbank, Morgenstood). Some 44% is
transformed primarily by cultivation, plantations, mines, urbanization and by building
dams. There are 10 South African Natural Heritage Sites in this unit, although very little of
it is formally protected. Land use pressures from agriculture are low (5% cultivated) due to
the colder climate and shallow soils. The following conservation areas are located within
the vicinity of the MRA:
Protected Areas
• Paardeplaats Nature Reserve (approximately 6 km to the south east);
• Pongola Bush Nature Reserve (approximately 8 km to the south); and
• Wakkerstroom Wetland Nature Reserve (approximately 13 km to the south west).
National Protected Areas Expansion Strategy (NPAES) Focus Areas:
• Moist Escarpment Grasslands (distributed adjacent to mining area running from
north-west through to south east).
4.5.3 Flora
4.5.3.1 Botanical Diversity
A total of 28 plant species were recorded during the field investigations (March 2014). A
physiognomically dominant grass layer is represented by 20 grass species (71.4%) and 8 Forb
species (28.6). The list of plant families recorded during the survey is presented in Table
4.4.
Kangra Coal (Pty) Ltd Maquasa East Discard Dump
13-347 9 March 2016 Page 68
Table 4.4 Plant families recorded (March 2014 survey)
GROWTH FORM SCIENTIFIC NAME COMMON NAME
Grasses
Poaceae
Themeda triandra Red Grass
Hypparrhenia hirta Common Thatching Grass
Cymbopogon excavatus Broad Leaved Turpentine Grass
Cymbopogon plurinodes Narrow Leaved Turpentine Grass
Heteropogon contortus Spear Grass
Elionurus muticus Wire Grass
Setaria sphacelata Golden Bristle Grass
Aristida congesta subsp. congesta Tassel Three-awn
Sporobolus africanus Ratstail Dropseed
Eragrostis capensis Heart seed Love Grass
Eragrostis superba Saw tooth Love Grass
Loudetia simplex Common Russet Grass
Eragrostis trichophora Hairy Love Grass
Eragrostis gummiflua Gum Grass
Melenis repens Natal Red Top
Eragrostis lehmanniaqna Lehmann’s Love Grass
Eragrostis curvula Weeping Love Grass
Eragrostis choromelas Curly Leaf
Aristida congests subsp. barbicollus Spreading Three-awn
Pogonartria squarosa Herringbone Grass
Forbs
Asteraceae
Gerbera viridifolia Pink gerbera
Bidens pilosa Blackjack
Gerbera ambigua Common gerbera
Aster bakeranus Baker’s wild aster
Helichrysum mudifolium Hottenot’s tea
Gerbera piloselloides Small gerbera
Gazania krebsiana Common gazania
Verbanaceae Verbena bonariensis Purpletop verain
4.5.3.2 Macro-habitat Types
Natural (untransformed) vegetation of the study area and the surrounding areas are
strongly representative of the regional vegetation types, exhibiting extremely limited
(localised) divergence from the species composition, diversity and vegetation structure
described by Mucina and Rutherford (Vegmap, 2006). Typical of the vegetation of the
region is that extremely little zonality is observed in vegetation forms.