Water quality at KCM
Konkola Copper Mines (KCM) in Zambia, which is Africa’s largest copper mining operation, has been in continuous production for over 60 years. Vedanta acquired a majority share of KCM in 2004. Konkola operates some of the wettest mining operations in the world – mining processes require ~350,000m3 of water to be removed every day.
KCM embarked on a 10-year, US$22 million project to improve the quality of its discharge water. Previously, sediments had been removed from the water flowing through the mines before being discharged to the surface. However, the concentration of suspended solids tended to remain high, which meant that additional measures were needed to improve water quality.
At KCM, suspended solids are primarily removed from water via 20 settling tanks, both on surface and underground. To improve the efficiency of these tanks, four major projects were undertaken:
- Refurbishment of existing underground settlers to make them more efficient
- De-silting of choked drain drives, which included the removal of mud that had accumulated over the years
- Procurement and installation of slurry pumps, which allowed the desludging period to be reduced from eight months to three weeks
- Procurement and use of flocculants to enhance settling
The immediate outcomes of the project have been two-fold:
- Suspended solids levels are now below the statutory threshold of 100 mg/l
- Wear and tear on pumping infrastructure is notably reduced due to improved water quality, which has lessened abrasive impacts