First Quantum Minerals Ltd. (FQM) is investing in a new trolley assist system for Hitachi dump trucks at the Kansanshi copper and gold mine, near Solwezi in Zambia. The massive project includes the installation of a new fleet of 23 electric EH3500ACII models as part of a four-year $370million expansion programme.
Three different project phases are planned to increase annual copper production capacity from the 230,000 tonnes achieved in 2011 to 400,000 tonnes by 2015. The trolley assist package commenced in March 2012 with the installation of a 750m-test track and overhead line for trials by Hitachi engineers.
Kansanshi is Africa’s largest copper mine – and the eighth largest in the world – with an estimated lifespan of at least 11 years. Eighty per cent of the mine is owned by Kansanshi Mining PLC (a FQM subsidiary) and the remaining 20 per cent belongs to a subsidiary of ZCCM Investments Holdings, 85 per cent of which is owned by the Zambian Government.
Mining is carried out in two open pits, which are known as Main and Northwest. FQM uses conventional open-pit mining methods and employs hydraulic excavators and a fleet of rigid dump trucks. The line-up of large Hitachi excavators includes: two EX1200-5s (with over 38,000 and 42,000 working hours respectively); four EX1900-5s (27-40,000); one EX1900-6 (over 14,000); and three EX2500-6s (7-20,000). However, the existing fleet of 11 EH3500ACII trucks is the most recent addition to the Hitachi stable at Kansanshi, with 2,000 to 6,000 working hours between them.
John Coleshaw, FQM’s Project Manager, says, "The EX1200s, EX1900s and EX2500s are quite old now, with some having accumulated more than 40,000 hours. They have given good service and we can’t fault them. The EH3500ACII is a good machine and our operators are happy with their working environment. A main benefit of these models is the automatic retarding control to regulate the downhill speed, which is excellent for safety and preserves the lifetime of the product."
The new EH3500ACIIs have started to arrive on the site and will be ready for full operation with the new trolley line by March 2013. The design of these electric dump trucks has become a more simplified process since the turn of the century. Technological innovation has opened the door for the powerful AC drive to replace the traditional DC drive.
The Assembly Coordinator for the Hitachi machines at Kansanshi is Hugo Truter of Hitachi Construction Machinery (Zambia), Ltd. (HCMZ), who says: "The trials have been going well and the trolley line will be extended by 2km to run from the base of the existing line to the bottom of the Main pit.
"The advantages of using the trolley line are reduced running costs – due to less fuel consumption – and the increased life expectancy of the equipment. The electric trucks excel in environmental performance, in terms of achieving low emissions and noise levels. They also have a lower risk of breakdown and require fewer parts, which in turn means lower costs, less maintenance and consequently minimum downtime."