Lonmin Platinum

At Lonmin Platinum Mine situated in Rustenburg, the Sulphur Fixation Plant (SFP) captures SO2 from the furnace and converter off-gas, predominantly as calcium sulphite / sulphate (CaSOx) solids. These solids are dewatered by the Regen Thickener (55THC001) ahead of vacuum filtering and disposal in a landfill.

To empty the Regen Thickener, its contents are currently dumped into the containment sump beneath, which makes maintenance difficult as the entire sump is flooded. A sump pump discharges the slurry onto a concrete trough that gravity drains into the Smelter process water corner dam, in order to gain access to the area for cleaning and maintenance work. Thickener slurry is high in sodium, resulting in contamination of the process water circuit and the loss of expensive reagent. As part of the SFP Upgrade Project, some of the main reasons for historically emptying the Regen Thickener are being addressed which should improve operations in the future.

However, to further improve the operability of the plant and increase availability, Lonmin chose to construct a dedicated Dual Alkali effluent dam to provide a better means for emptying the thickener, recover the liquid reagent and dispose of the dried solids to landfill during planned and unplanned outages. G4 Mining and Civils (Pty) Ltd was awarded the contract for the Dual Alkali Effluent Sump and commenced work on 26 April 2019.  The project was completed in January 2020 with a project value of R13 000 000, and included construction of:

• – Reinforced concrete effluent sump
• – Pump chamber
• – Liquor chamber
• – Gravel roadway and loading pad
• – Pipe structure support foundation
• – Flocculant plant foundations
• – Thickener underflow pump base
• – Cable rack support plinths

Total concrete on the project – 850m³

Total earthworks – 13 500m³