Groundwater flow through Konkola (Bancroft) copper mine - Zambia

Abstract

This thesis describes the results of field based research on the Konkola (Bancroft) underground copper mine groundwater flow problem, in Zambia. Konkola is one of the wettest mines in the world, pumping an average of 360,000 m^/d of water. To understand how groundwater flows into and through the mine and subsequently formulate a long-term cost-effective groundwater management solution, an integrated study of historical and current dewatering and mining records, structural geology, surface hydrology, rock chemistry and groundwater chemistry, was carried out. The results enabled the development of a numerical model, to be used to make groundwater discharge and water level drawdown predictions for future groundwater management decisions. The results obtained clearly reveal that; mine water can be divided into that which originates from surface recharge close to the mine and that which originates from regional aquifers at depth. This has enabled the origin of water in the mine to be essentially established. A considerable percentage of the water entering the mine comes via the Hangingwall Aquifer with its connection to the surface sources of recharge. Flow to the mine is dominated by flow through fractures and fissures which form zones of high conductivity. The flow in these zones can be modelled by finite difference networks. Significant reduction of water inflow into the mine can be achieved by implementing a water-exclusion groundwater management solution.