JOHANNESBURG (miningweekly.com) – The official sod-turning ceremony for the construction of the Mogale tailings retreatment project is to take place this month.
The Mogale gold dumps contain a probable mineral reserve of 123.6-million tons of re-mineable material at a head grade of 0.29 g/t for an estimated content of 1.14-million ounces of gold.
The definitive feasibility study (DFS) points to fast payback, low costs, 25% production uplift, long life, high ungeared return and the upliftment of a depressed area, where there is low employment, illegal mining activity, and serious environmental degradation.
Seen as an important mining and rehabilitation development for the West Rand District, the project – being undertaken by London- and Johannesburg-listed Pan African Resources – is expected to produce an average of 50 000 oz of gold a year over 20 years.
Near Krugersdorp and Kagiso, west of the Golden City of Johannesburg, it is expected to provide economic opportunity, local procurement, and jobs during construction and ongoing operations.
Modern technology was employed to survey available tonnages across the project area, with historical holes twinned to verify previously reported head grades. More than 80 new boreholes were sunk – totalling some 2 761 m of drilling – in areas with little or no data.
The DFS pointed to operating costs of R78/t and an all-in sustaining cost of $914/oz.
Standard hydro mining will be deployed and a large carbon-in-leach facility built, where the remined tailings will be processed with additional water treatment that will potentially improve gold recoveries.
At Pan African’s existing Elikhulu and Barberton tailings retreatment plants, optimised tailings management has reduced the pollution load on the surrounding land and underground water resources. This has resulted in improved freshwater quality and lower levels of radiation and toxicology, allowing the re-introduction of indigenous flora and fauna species to the area, which has shown an ability to recover faster. These same benefits can now be extended to the West Rand facilities.
Solar power generation is also on the cards at Mogale by Pan African, which pioneered the 10 MW photovoltaic solar plant at Elikhulu. Targeted by the group is an overall 30 MW of solar capacity by 2024. This will produce about 75 000 MWh of power a year, save about R100-million a year in electricity bills and reduce group carbon emissions. Beyond solar, battery technology and wind power are also under consideration.
The recovery of gold from dumps is viewed as a must as part of environmental restoration and making land available for proper re-use.