The Bisha Mine is located in a semi-arid ecosystem and careful water stewardship is one of our most pressing economic, environmental, and social issues. We continually look for ways to minimize fresh water use and maximize water recycling to protect community water sources and surrounding habitats. On an ongoing basis, we monitor daily water balance and consumption, and conduct regular water quality and groundwater table monitoring.
In 2016, we extracted 2.38 million cubic metres (m3) of water for operations compared to 1.74 million m3 in 2015 (a 27% increase), as shown in the table. The increase is a direct result of zinc being added to the process as more water is required for this metal than for copper. The decline in water consumption in 2015 meanwhile, was due to the changing process demands of shifting from gold to copper production in late 2014 and the temporary suspension of operations in 2015 due to a fuel shortage.
Most water used at the mine is groundwater, drawn primarily from the Mogoraib aquifer. Smaller amounts of water are added from dewatering the mine pit located in the Freketetet aquifer and an aquifer near the Harena pit.
There are legitimate concerns when a mining operation in a semi-arid environment competes for limited water resources with nearby communities, native plant ecosystems, and animal populations – resident and nomadic.
Both the Company and two local communities (Mogoraib and Adarat) rely on the Mogoraib River aquifer. The remaining two aquifers supplying Bisha Mine are not shared with any community due to distance. Rainfall only contributes limited water resources, primarily supporting our rehabilitation activities.
In 2015-16, BMSC updated and extended our regional hydrogeology study to evaluate the interactions between competing users of the Mogoraib River aquifer (see text box for key study results). The study provides more comprehensive information regarding aquifer dynamics and recharge, and is being incorporated into the mine water management plans.
The primary water demand is in the process plant. Water is considered a valuable resource and BMSC invests in technology to further improve our reuse. Water is recovered from the tailings before discharge to the pond and recycled from the Tailings Management Facility (TMF) and returned to the plant as process water. Treated sewage also discharges to the TMF. In 2016, approximately 107,105 m3 (4.5% of water use) was recycled from the TMF, a reduction of 10% over the amount recycled in 2015. The decrease is related to the increased acidity of the tailings pond due to the practice of sending pit water to the TMF. The acidic nature of the pit water, combined with the metal species (i.e., free Cu), impedes recovery in the plant. An upgraded return water treatment plant was inaugurated in late 2016, which should increase the recycle rate. No water is discharged from TMF to the surrounding area as it does not meet the IFC effluent discharge standard.
Water quantity and quality is monitored continuously on-site. The environmental laboratory was significantly advanced in 2016 and is now fully operational.