Development of a Suitable Mine Backfill Material Using Mine Waste for Safe and Economic Ore Production at Konkola Mine (Zambia)

摘要

Use of backfill material in mining operations has progressively become a fundamental part of underground mining operations in most mining houses worldwide. This has mainly been driven by the need to increase ore recovery and productivity. One of the methods to increase ore production has been through complete ore extraction from underground The underground mining activities have lead to creation of large volumes of voids which, if not addressed, would lead to long term global instability of the mine. The ever-increasing depths reached by underground mining will, in the future, place even more demands on sound backfill and mine design systems if safe and efficient operating conditions are to be maintained. It has been recognized that carefully engineered and efficiently run backfill systems can significantly enhance a mining operation. By contrast, badly engineered and poorly run backfill can be a serious impediment to the mine and, worst of all, compromise safety Geotechnical investigations have been carried out on the available mine waste materials at Konkola Copper Mine (KCM) in Chililabombwe, Zambia, to develop a suitable backfill material which would facilitate complete ore pillar recovery underground and ensure safe and economic ore production at Konkola mine (Zambia). The material would need to have the strength of 1 MPa, as spelt out by Konkola mine management and suitable drainage characteristics to resist failure due to self weight in a backfilled stope and therefore facilitate total ore extraction from underground Geotechnical tests have shown that the suitable backfill material for safe and economic ore production at Konkola Mine is the blend between the hydraulic fill material produced at 65% solid fraction at the old backfill plant and waste rock the mine dump crushed to 2.83 mm size. The blend ratio must be 3:7 by weight, respectively, with addition of 4% Zambezi Portland cement. This material, mixed on surface, must be pumped to the various stopes underground at Konkola Mine and allowed to cure for not less than 28 days to attain the recommendea UCS of 1 MPa needed to facilitate total ore pillar recovery.