An attempt to reduce the delays that impact on its main face is already beginning to reap benefits for UK Coal’s Rossington colliery in South Yorkshire. This year gate belt conveyors have improved their running time to an average 95%, with a potential increase of over 9,000 tonnes, reported the company newsletter NewScene in April.
The mine has been in review because of geological and financial problems. Earlier this year UK Coal said it had received £3.3 million in investment aid for Rossington which only produced 82% of targeted output in 2003.
As part of identifying a way forward, a four-man team – conveyor manager, mecahncial and electrical shift charge engineers and an overman – are working to identify conveyor delays as an initial target.
The mine’s ROM production is transported on a 14km long conveyor system and Mondays are spent discussing the delays that occurred in the previous seven days. Using the colliery information system, information is catalogued and repeated delays are highlighted.
“While major breakdowns, tracking issues and roller failures are dealt with immediately, the main aim is spotting trends which have the knock-on effect of a few minutes lost regularly here and there,” said conveyor manager Dale Lockley.
One recurring hold-up involved drive drums and once the problem was solved an average 120 minutes a week was saved. A patrol system and workmen back up belt maintenance, each covering a zone either side of the 1,000t vertical bunker throughout a shift.
“A ten minute stop on one of our 48 inch, 1,500 tph conveyors costs the pit £7,500 in lost revenue,” Lockley said.
Meanwhile, the installation of a new belt jointing station at Thoresby colliery for 5,000m of conveyor belt has resulted in a safety bonus and a 40% saving in time. It now takes 55 minutes to build a joint into the conveyor, allowing the pit to complete five joints a weekend.
Some 48 joints couple together the mine’s main belt installation which is rated at 2,000tph. Each joint is renewed every six months which previously took six mine staff 90 minutes to complete. This involved hauling the belt out of the loop, using an electric Pickrose haulage winch, clamps, pull lifts and torque wrenches.
Now re-making a joint is like attaching a zip to the 1554 inch, 20mm thick belt. A 9mm stainless steel pin provides the connection between the two belt ends.
“The weekend maintenance belt staff are pleased with the device because it’s quicker and easier. More important it’s safer because of the reduction of manual handling and use of lifting equipment previously required,” said conveyor manager Trevor Lowe.