Design and Construction of the Nchanga Copper Tailings Leach Plant Stage 3

Abstract

The Nchanga Division of Zambia Consolidated Copper Mines Limited (ZCCM), the largest producing copper mine in the Commonwealth, has recently commissioned a new plant for reprocessing copper rich tailings. The tailings, some 140 million tonnes in total, are stored in large paddock dams. This paper records the problems and successes involved in completing the design, procurement and construction of the project, on time and ten per cent below budget. Design and project management was by Zambia Engineering Services Limited in Ashford, Kent, a subsidiary of ZCCM, and project funding was from a consortium of international hanks, export credit agencies and development organizations. The subjects dealt with include process design, project capital and funding, management, design and the use of models, estimating and cost control, planning, purchasing and procurement, construction and commissioning. The paper also highlights the problems associated with funding a new project of this type in the Third World in a depressed metals market, and the role of engineering in overcoming financial delays and transport problems. Commissioning started in April 1986 and the plant is now coming up to full production with a few, but not unexpected, problems bearing in mind the size and complexity of the plant. With the addition of stage 3 to the tailings leach plant at Nchanga throughput of ore is increased from 850 000 tonnes/month to 1500 000 tonnes/month and copper output by 40 000 tonnes/annum for a total cost of $250 M.