Since the shearer’s installation in April, monthly output has doubled from 420,000 tonnes run of mine to 870,000t in July.

Coal is mined at an extraction height of 4.5 meters from a coal seam height of 5-6m across a face width of 250m. Shifts of 3 x 8 hours per day are worked on the face which is normally manned up 24 hours a day.

While the 1860 kW machine performed well initially, the hard cutting conditions, continuous operation and very high production demands required the ranging arms and haulage system to be beefed up.

Working closely with the customer’s engineers and managers, Joy service engineers manufactured gearing to increase the drum speed while larger drums (supplied by the mine) were installed to reduce the load on the trailing drum.

The machine had its best day since start up during the week of July 21 when it cut 38 webs, while the daily average for the week was 34 webs. This is a run-rate of over 1 million tonnes per month.

There still remains some potential for even higher settings and correspondingly higher output, as experience is gained with certain components of system, Joy said.