Modern Mining September 2016

COAL

commissions on schedule

Cementation’s involvement at Impumelelo – which is an entirely ‘greenfield’ project – has extended well beyond the underground bunker. “We were appointed in 2011 as the contractor for the sinking of the two vertical shafts – the main and ventilation shafts – the mine requires and also for decline development,” he says. “The first resources arrived on site in May 2011, although the formal sod turning and contract signing only took place several months later in August. Both vertical shafts have been sunk to a depth of 200 m with the main shaft being 11,7 m in diameter and the vent shaft 6,5 m. The decline is 1 000 m long, dips at 17 deg and has a width of 6,5 m and a height of 3,5 m. “We commissioned the main shaft in December 2014 and in January 2015 the first Continuous Miner (CM) – eventually there will be 10 CMs – started cutting coal. In August 2015 we commissioned the decline conveyor to 4 Seam and in the following month the ven- tilation shaft fans were commissioned. With the coal bunker having become operational on 9 June 2016, we are now all but complete at Impumelelo with the final value of Murray & Robert’s contract – including the bunker – being R1,06 billion.” Turning to the coal bunker, Wells says it was constructed over a period of a year (starting in May 2015), with Murray & Roberts Cementation

deploying a team of just under 100 to undertake the work. Excavation extended over roughly the first six months with construction – civils and structural steelwork – occupying the remain- ing six months. “It was a massive undertaking and we were under huge pressure to meet mile- stones but fortunately we were able to meet all the critical interface dates,” he comments. “I attribute the success we had to the intensive planning we put into every phase of the opera- tion and also the cooperation and support we

Above: Isometric view of the box front structure. Left: Coal discharging into the 1 500-ton capacity bunker. Note the steel walkway – this alone weighed 3,5 tons. Centre: The box front showing the feed level (below) and chute level. Below: Chute level of the box front. Each chute weighs about 4 tons fully assembled.

September 2016  MODERN MINING  23