Draft Status Quo Report for the Pixley Ka Seme ... - SRK Consulting

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SRK Consulting in association with BKS Pixley Ka Seme Local Municipality EMF – Draft Status Quo Report Page 23 lower down the slopes. The western extremity of the study area is characterised by soils which are comprised of clay. The bulk of PKSLM has loam clay/loamy soils while the western section is dominated by sandy loam/loam. The far northern portion along the Vaal River has sandy alluvial soils. The arability of the soils of the study area is depicted in Map 7. High potential arable soils are restricted to the north-eastern portion of the study area. 3.2.4 Topography and geomorphology The north-western part of PKSLM is characterised by undulating landscape of the Highveld Grasslands. These areas reach heights of 1,600 to 1,700 m above sea level. The south eastern part of the municipal area is more rugged and hilly, characterised by low to high mountains in the Volksrust and Wakkerstroom areas as a result of the presence of the resistant sandstone beds. The Langkrans, Versamelberg, and Langberg in the vicinity of Volksrust reach over 2,000 m above sea level, while those near Wakkerstroom reach above 2,200 m. Dolerite sills give rise to characteristic flattopped hills. Topography of the study area is depicted in Map 8. 3.2.5 Geology The study area is situated entirely on rocks of the Karoo Supergroup. Dolerite sills are intruded along bedding planes of sedimentary rocks, or as dykes intruded at right angles to the bedding. The intrusion of the dolerite results in resistance to weathering and gives rise to hills and ridges (see Map 8 and Map 9). Dolerite weathers to clayey soils, which are expansive and problematic to building foundations. Coal resources Coal mining activity is limited in the PKSLM, with the Savmore Coal Mine on the eastern extent being the only operational mine. There are small as well as defunct coal mining operations outside the study area near its eastern border, as well as to the north in the Ermelo district (SRK, 2010). Small-scale coal mining is occurring in the east where seams are close enough to the surface to support this level of exploitation. East of Amersfoort there are prospecting rights for coal. There are also prospecting rights well to the south-east of Wakkerstroom. There has been a recent application (July 2010) for prospecting rights on a farm in the Utrecht magisterial area of KZN. This farm is within the Enkangala Grassland Project domain, and about 3-4 km outside of Wakkerstroom (Angus Burns, pers. comm.) The coal seams are generally flat-lying to gently undulating with a regional dip to the southwest. Faulting and associated dolerite intrusions are common throughout the coalfield, but increase to the south where they impact on mining potential. The coal resource forms part of the Ermelo Coalfield, with five coal seams denoted from A to E starting at the surface located in Vryheid Formation. The B and C seams are most widely developed to mineable thicknesses. The beds of the Vryheid Formation outcrop over the eastern portion of PKSLM providing some potential for open-cast coal mining. The highly weathered seams are not generally amenable to good coal recovery, and activities are likely to be restricted to small-scale recovery by entrepreneurs using low-cost mining methods. Their marginal nature is likely to present a challenge to compliance with environmental management programmes and financial provision for rehabilitation. The distribution of existing coal boreholes is shown in Map 10, while Map 11 shows the extent of potential underground and surface mining for PKSLM. Underground mining would be required to access coal reserves to the west where they are overlain by shales and siltstones of the Volksrust Formation. There also appears to be potential for underground coal mining in the remainder of the study area where the coal resource is more than 50 m deep and the coal seam is at least 1 m wide (see Map 11). Since the Majuba Coal Mine was decommissioned, the Majuba power station south of Amersfoort has been supplied by coal trucked from as far afield as Witbank. Underground Coal Gasification (UCG) technology converting unmined local coal seams into combustible gas is being piloted to supply the power station (Engineering News, 2007). Should the pilot project prove successful, it could give rise to similar projects utilizing the deep-lying coal resources. KILI/BEAT G:\404946_PIXLEY EMF\7REPORTS\Status Quo report\Draft report\Draft status quo report, July 2010.docx July 2010
SRK Consulting in association with BKS Pixley Ka Seme Local Municipality EMF – Draft Status Quo Report Page 24 Other mining The geological materials present in PKSLM are not considered to be that favourable for exploitation as construction materials. However there is some sand and aggregate mining in the northern and north eastern parts of the study area, and rock quarrying in the central parts (see Map 32). 3.2.6 Water resources Surface water quantity The PKSLM is situated in the headwaters of three major rivers and Water Management Areas (WMAs), namely the Upper Vaal, Thukela and Usutu to Mhlatuze (see Map 12 for WMAs and major surface water sources, and Section 3.2.7 for information on the numerous wetlands in PKSLM). The bulk of the study area falls in the Upper Vaal WMA, while the eastern portion falls in Usutu to Mhlatuze WMA and the southeastern portion lies in the Thukela WMA (in Van Niekerk et al., 2010). PKSLM totally and/or partially contains 14 quaternary catchments (see Table 3-1). The portion of the Upper Vaal WMA that falls within the PKSLM comprises tertiary catchments C11 and C13. The C11 catchment is upstream of Grootdraai Dam and C13 comprises the Klip River that joins the Vaal River downstream of Grootdraai Dam. The Usutu WMA comprises the Assegaai and Hlelelo Rivers as well as the Heyshope Dam in the tertiary catchment W51. The portion of the PKSLM which falls within the Thukela WMA, includes the towns Wakkerstroom and Volksrust in tertiary catchment V31 upstream of Zaaihoek Dam in the Slang River, a tributary of the Buffalo River. Quaternary Catchment Table 3-1: Details of the 14 Quaternary Catchments in the study area Combined Catchment area Forestry Alien veg. Irrigated minor dams MAE MAP Gross Net area area area area volume (km 2 ) (km 2 ) (km 2 ) (km 2 ) (km 2 ) (km 2 ) (mcm) (mm) (mm) C11B 536 536 0.00 0.00 0.83 0.49 1.61 1,400 705 C11C 450 450 0.00 0.00 0.71 0.10 0.38 1,400 765 C11D 373 373 0.00 0.00 0.59 0.69 1.54 1,400 702 C11E 1,157 1,157 0.00 0.00 1.78 0.81 1.31 1,400 697 C11J 1,002 1,002 0.00 0.00 1.54 0.19 0.29 1,450 658 C11L 948 948 0.00 0.00 1.48 0.61 1.63 1,450 675 C13A 595 595 0.00 0.00 0.57 0.09 0.20 1,400 779 C13B 616 616 0.00 0.00 0.71 0.00 0.00 1,400 683 C13D 896 896 0.00 0.00 0.99 0.00 0.00 1,400 698 V31A 622 622 0.00 1.70 4.42 0.02 0.30 1,400 916 V31B 505 505 20.40 21.80 5.18 0.51 2.10 1,400 856 W42C 377 377 10.40 1.10 0.00 0.00 0.00 1,400 1,017 Source: WRC (2008) The accumulated stream flow varies greatly from a high 264 mm in the east upstream of Heyshope Dam to a low 57 mm in the west. The Upper Usutu to Mhlatuze WMA in PKSLM including the Zaaihoek Dam is already highly developed and cannot sustain additional water use. Water transfers to the Upper Vaal and Olifants WMA, and afforestation account for the bulk of available water. The Upper Vaal WMA receives the bulk of available water by relatively high quality water transfers from the Upper Usutu to Mhlatuze. There is a large projected growth in demand in the WMA as a whole, but also for additional requirements in its upper reaches for petrochemical industries and power generation. The Thukela WMA is the source of water for the Thukela-Vaal Transfer Scheme which, inter alia, transfers water from the Thukela River catchment to the Sterkfontein Dam in the Vaal River system. International obligations govern the supply of water to neighbouring countries of Namibia, Swaziland and Mozambique situated downstream of the three WMAs whose headwaters fall in the study area. Surface water quality The overall quality of the rivers in the region is acceptable. Besides mining activities in the PKSLM, discharge from the various Waste Water Treatment Works (WWTW) pose a potential threat to the water quality in the rivers (see Section 3.3.2). Surface water quality in the PKSLM is indicated in Map 13, and can generally be described as follows (in Van Niekerk et al., 2010): • Water resources in the vicinity of major centres have poorer water quality than outlying areas mainly due to effluent outflow from WWTW battling with under-capacity and maintenance; • Total Dissolved Solids (TDS) concentrations are below 270 mg/l or 30 mS/m, and are thus acceptable for drinking water; • Calcium sulphate salts are dominant in the rivers, indicating water quality influences from acid mine wastes and many other industrial processes such as tanneries, textile mills and processes using sulphuric acid or sulphates. Atmospheric sulphur KILI/BEAT G:\404946_PIXLEY EMF\7REPORTS\Status Quo report\Draft report\Draft status quo report, July 2010.docx July 2010
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