discharge of treated water - zitholele - largo/3... · 2012-08-03 · the proportional loss of...
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Ref: C184-MP-Disch-Rev0
New Largo
TECHNICAL NOTE
DESCRIPTION Anglo American Inyosi Coal
New Largo Colliery
PRELIMINARY DISTRIBUTION OF DISCHARGE OF TREATED WATER
JOB NO. C184
REF C184-MP-Disch-Rev0
FILE NAME C184-00_NTE-02_r0_mmmp_NewLargo-PrelimDischAlloc-111222.docx
DATE 22 December 2011
1 INTRODUCTION
The proposed Anglo American Inyosi (AAIC) Coal New Largo Colliery straddles the watershed between the Wilge River in the west and the Saalklapspruit in the east. The opencast pit will mine through headwater tributaries of both rivers, resulting in a reduction in the runoff reporting to each river. In addition, the containment of dirty runoff from the infrastructure areas will also reduce the runoff in the natural streams.
However, the mine will operate with a water surplus (i.e. the dirty water make will exceed the reuse of dirty water on the mine). It is therefore planned to construct a water treatment plant, which will treat the dirty mine water make to potable standards. This will supply the mine’s potable water needs, with the surplus treated water being discharged to the natural system.
In order to mitigate the flow reduction in each affected stream, AAIC plans to distribute the treated water proportionately amongst the affected streams.
The final allocation of discharge to each stream will be determined jointly by the surface water specialist (Jones & Wagener (J&W)) and the wetland specialist (Wetland Consulting Services (WCS)), once the reserve determination study (currently being carried out by WCS) has been completed. It is currently anticipated that the reserve determination study will be completed in March 2012.
However, AAIC requires a preliminary assessment of the allocation of discharge prior to this date. J&W were therefore requested by Mr Lampies Lamprecht of AAIC, during the New Largo Water Management Meetings, to carry out this preliminary assessment.
It is important to note that the assessment given in this note is PRELIMINARY and is based on surface water runoff considerations only. The outcome of the reserve determination study can be expected to significantly alter the distribution of flows given here.
2 ASSESSMENT
The affected sub-catchments were delineated for both the base case (LOM Rev 6) and alternative case (LOM Rev 7a). Each sub-catchment was allocated a number. These are shown in Figures 1(a) and (b) respectively. Prospective discharge points, or nodes, were identified in the watercourses surrounding the mining area, also indicated on the figures.
2
Ref: C184-MP-Disch-Rev0
New Largo Colliery
In this assessment, the proportional flow reduction, and therefore the proportional distribution of treated water discharge, has been based entirely on the affected catchment areas (i.e. the assumption that the flow reduction will be directly proportional to the catchment area lost).
The proportional loss of catchment was determined at key stages in the life of mine for both LOM revisions.
The area of each sub-catchment, as well as the node towards which it drains, is shown in Tables 1 and 2 for LOM Rev 6 and Rev 7a respectively.
Table 1 Catchment areas and discharge point for LOM Rev 6 Refer to Figure 1(a)
Sub-Catchment
Number
Area
(km2)Drains to node
1 0.88 NLD1
2 0.27 NLD15
3 0.76 NLD14
4 0.87 NLD2
5 3.20 NLD3
6 1.84 NLD4
7 0.96 NLD5
8 6.54 NLD6
9 1.16 NLD7
10 1.41 NLD7
11 0.81 NLD8
12 5.25 NLD8
13 1.56 NLD8
14 0.13 NLD9
15 2.86 NLD9
16 0.93 NLD10
17 0.19 NLD10
18 0.06 NLD10
19 3.42 NLD10
20 7.30 NLD11
21 0.03 NLD10
22 3.98 NLD16
23 2.93 NLD12
24 3.40 NLD12
25 1.69 NLD12
26 4.10 NLD1
27A 5.35 NLD13
27B 0.45 NLD12
TOTAL 62.33
3
Ref: C184-MP-Disch-Rev0
New Largo Colliery
Table 2 Catchment areas and discharge point for LOM Rev 7a Refer to Figure 1(b)
The catchments affected at key stages during the LOM are presented in Tables 3 and 4 for LOM Rev 6 and Rev 7a respectively. In these tables the discharge allocated to each prospective discharge point is expressed as a percentage of the total discharge.
Note that while it is acknowledged that the opencast will be rehabilitated concurrently to mining, with clean runoff from the rehabilitated areas being returned to the catchment, the mine water make (and therefore the volume of treated water to be discharged) will increase significantly over the life of mine. The rehabilitated areas have therefore not been taken into account in this assessment, as there will anyway be a need to distribute the treated water so as to limit the impact of the increased flows on the individual watercourses.
Sub-Catchment
Number
Area
(km2)Drains to node
1 3.90 NLD1
2 0.72 NLD3
3 1.84 NLD4
4 0.96 NLD5
5 6.54 NLD6
6 1.16 NLD7
7 1.41 NLD7
8 0.81 NLD8
9 5.25 NLD8
10 1.56 NLD8
11 0.13 NLD9
12 0.03 NLD10
13 2.86 NLD9
14 0.93 NLD10
15 0.19 NLD10
16 0.09 NLD10
17 3.42 NLD10
18 7.30 NLD11
19 3.98 NLD16
20 2.93 NLD12
21 3.40 NLD12
22 1.69 NLD12
23A 5.35 NLD13
23B 0.45 NLD12
TOTAL 56.90
4
Ref: C184-MP-Disch-Rev0
New Largo Colliery
Table 3 Preliminary allocation of discharge to prospective discharge points for LOM Rev 6 (refer to Figure 1(a))
Table 4 Preliminary allocation of discharge to prospective discharge points for LOM Rev 7a (refer to Figure 1(b))
By 2019 By 2034 By 2049 By Closure
NLD1 4.98 8.0 32.3 13.4 9.4 8.8
NLD2 0.87 1.4 2.3 1.6 1.5
NLD3 3.20 5.1 8.6 6.0 5.7
NLD4 1.84 3.0 4.9 3.5 3.3
NLD5 0.96 1.5 2.6 1.8 1.7
NLD6 6.54 10.5 17.6 12.3 11.6
NLD7 2.57 4.1 4.8 4.5
NLD8 7.62 12.2 11.4 13.5
NLD9 2.99 4.8 5.3
NLD10 4.63 7.4 8.2
NLD11 7.30 11.7 13.7 12.9
NLD12 8.47 13.6 33.0 22.8 15.9 14.2
NLD13 5.35 8.6 34.7 14.4 10.1 0.0
NLD14 0.76 1.2 2.0 1.4 1.3
NLD15 0.27 0.4 0.7 0.5 0.5
NLD16 3.98 6.4 10.7 7.5 7.0
TOTAL 62.33 100.0 100.0 100.0 100.0 100.0
PRELIMINARY allocation of discharge:
Percentage of total disharge to be released at
each discharge pointProspective
discharge point
Total affected area
draining to
discharge point
(km2)
Percent of total
affected area
draining to
discharge point
By 2019 By 2034 By 2049 By Closure
NLD1 3.90 6.9 27.2 10.0 8.2 7.6
NLD2
NLD3 0.72 1.3 1.8 1.5 1.4
NLD4 1.84 3.2 4.7 3.9 3.6
NLD5 0.96 1.7 2.5 2.0 1.9
NLD6 6.54 11.5 16.7 13.7 12.8
NLD7 2.57 4.5 5.4 5.0
NLD8 7.62 13.4 12.7 14.9
NLD9 2.99 5.3 5.9
NLD10 4.66 8.2 9.1
NLD11 7.30 12.8 18.7 15.3 14.3
NLD12 8.47 14.9 35.5 21.7 17.8 15.7
NLD13 5.35 9.4 37.3 13.7 11.2
NLD14
NLD15
NLD16 3.98 7.0 10.2 8.3 7.8
TOTAL 56.90 100.0 100.0 100.0 100.0 100.0
PRELIMINARY allocation of discharge:
Percentage of total disharge to be released at
each discharge pointProspective
discharge point
Total affected area
draining to
discharge point
(km2)
Percent of total
affected area
draining to
discharge point
5
Ref: C184-MP-Disch-Rev0
New Largo Colliery
Figures 1(a) and (b) attached overleaf. Note by:
MA Moodley BSc Eng MW Palmer MSc Eng for Jones & Wagener Document source: C:\AllJobs\C184_NewLargo\Word\C184-00_NTE-02_r0_mmmp_NewLargo-PrelimDischAlloc-111222.docx Document template: Memo_tem_Rev2_Jan09.dot
0 1 2 3 4km
MINEBOUNDARYPHOLA-KUSILE
CONVEYOR ROUTE
B2H14
Wilg
erivi
er
Klipfonteinspruit
Saalklapspruit
Wilg
erivi
er
Klipfonteinspruit
Saalklapspruit
18 21
General arrangement of catchment area lost due to mining for mine plan Rev.6
ANGLO AMERICAN INYOSI COALNEW LARGO COLLIERY
Job No C184-03
Scale 1 : 75 000(A3)
MINING INFRASTUCTURE
CATCHMENT AREAS LOST
LEGEND
DISCHARGE POINTSNode NLD13
NODE NUMBER14
MINEBOUNDARY
PHOLA-KUSILECONVEYOR ROUTE
B2H14
Wilg
erivi
er
Klipfonteinspruit
Saalklapspruit
Wilg
erivi
er
Klipfonteinspruit
Saalklapspruit
General arrangement of catchment area lost due to mining for mine plan Rev.7
ANGLO AMERICAN INYOSI COALNEW LARGO COLLIERY
Job No C184-03
Scale 1 : 75 000(A3)
MINING INFRASTUCTURE
CATCHMENT AREAS LOST
LEGEND
DISCHARGE POINTSNode NLD13
NODE NUMBER14
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