Geohydrological Investigation General Waste (Witkoppies) Landfill Site, Eskom Majuba Power Station

A geohydrological investigation was carried out for the Majuba General Waste Landfill Site at Majuba Power Station located within the jurisdiction of the Gert Sibande District Municipality. The site is located on Portions 1 and 6 of the farm Witkoppies 81 HS located on the southern side of Majuba Power Station.

Our geotechnical firm conducted a comprehensive geohydrological study for the Majuba Power Station’s General Waste Landfill Site within Gert Sibande District Municipality’s jurisdiction. Situated on Witkoppies farm’s portions 1 and 6, this project demanded the precise water sampling of resources within a kilometer radius at five different locations.

Drilling three monitor boreholes and performing yield testing was an integral part of the fieldwork. Furthermore, a water laboratory in Empangeni, accredited by the South African National Accreditation System (SANAS), diligently analyzed the borehole water samples.

Originally, the plan involved decommissioning the current landfill site and establishing a new one along the eastern boundary access road. However, an ‘Alternative Site’ was also contemplated to the south of the existing landfill. Hence, a combined study area of 10 hectares was examined.

The site is predominantly underlain by Vryheid Formation’s shale and sandstone sediments. Intrusions of Post-Karoo dolerite, typically capping the area’s low hills, have also been observed. The geology of the freshly drilled boreholes predominantly revealed carbonaceous shale with some sandstone and a dolerite sill varying from 3m to 14m thick.

The locale is draped by transported soils, including hillwash and alluvium, over its bedrock. Numerous hillslope seepage wetlands, suspected to emanate at the dolerite/sedimentary bedrock contact zones, form spring lines at various elevations. These wetlands support thriving hydrophilic grasses and shrubs.

LL3034 01 Majaba PS Loc

Historically, the region surrounding the site was agricultural land. Now, it boasts expansive pastures and lush Eragrostes grass. Moreover, the closed landfill site has developed a Kikuyu grass cover, hosting a few alien shrubs and a lone Acacia Karoo sapling.

Weather data spanning 38 years (1980-2017) from the Meteorological Station No. C1E007, located about 50km north-northwest of the Majuba Power Station, was utilized.

Despite potential air quality concerns, no odours emanating from the closed landfill site were detected during the site visits in 2018 and 2022. Gas and odour generation appears negligible, and the prevailing wind during the day is mainly from the west, with strong wind speeds and minimal calm periods.

Regarding groundwater potential, the yield range for BH1 is unknown. Recent boreholes demonstrated yields varying from dry to <1l/s. These monitor boreholes are earmarked for livestock watering only and comply with a ‘Low’ type of aquifer classification. These aquifers will solely be utilized for monitoring groundwater in the vicinity of the landfill site.

An established rating and ranking system was used to assess potential environmental impacts from construction, operation, and closure phases of the landfill site. All impacts identified hold medium to high negative significance, but with proper mitigation measures, these can be decreased to low or medium.

LL3821 03A1 Eskom Majuba LFS Reg Geology

A groundwater quality monitoring program is set to be implemented once the site becomes operational, in alignment with DWAF Minimum Requirements for Waste Disposal by Landfill (2nd Edition, 1998). This program will monitor boreholes BH1, BH2, BH3, and BH4.

The proposed Alternative A landfill site, east of the closed landfill site, should be developed primarily because it doesn’t interfere with the uppermost spring line and has sufficient cover soils for interlaying and capping. However, this development can only proceed with the strict implementation and adherence to the recommended mitigation measures. With these precautions in place, this project can indeed secure environmental authorization.

About the author