Focus on Harsh Environments: How to mine more yet maintain less

From increasing its scheduled maintenance activities from five per cent to 40 per cent, to reducing unplanned shutdowns in targeted areas by 50 per cent, a new approach to maintenance at the Brunswick Mining Division (Bathurst) of Noranda Mining and Exploration Inc., has yielded big rewards since its launch in 1999.

“The improvements are excellent in some areas,” says Jean-Guy Paulin, the Bathurst, N.B., mine’s information and maintenance systems superintendent.

“When we started the maintenance management process improvements, we hired Strategic Asset Management Inc. (SAMI) from the United States to help make an assessment of our maintenance practices and provide guidance. The first part of the program was to improve the work management process — work ID, prioritization, planning and scheduling. We [also] decided to start a maintenance reliability improvement program with SAMI’s help.

“Our efforts in reliability have enhanced the efficiency of the maintenance group and increased the availability of our equipment,” says Ron Tessier, the Bathurst operation’s plant manager.

Most areas of the mine’s operations are covered, and scheduled maintenance has risen rapidly. It includes “anything that we can identify ahead of time, that we can organize,” says Paulin. The figures were six per cent planned and scheduled in 1998 and 36 per cent in 2001. That year, of a total of 483,000 maintenance work hours, 175,000 hours were scheduled a week in advance. In the first five months of 2002, the figure rose to 41 per cent. “The intention is to reduce the amount of breakdown maintenance,” says Paulin.

Maintenance time against production has dropped, even as production has increased: The tonnage of ore mined rose from 3.2 million tonnes in 1998 to 3.5 million tonnes in 2001, and concentrate production rose 21 per cent to 786,000 tonnes in the same period. Yet maintenance hours dropped six per cent to 483,000 hours in the same period and overtime dropped by 15 per cent to 30,000 hours. One of the contributing factors is the reliability improvement program, according to Paulin.

Ore mined per man-hour of maintenance increased by 17 per cent to 7.4 tonnes in the same period. “I was expecting an improvement in productivity because we were concentrating on getting better at repairing equipment and reducing shutdowns,” Paulin says.

Six Sigma techniques used

The Brunswick mine used Six Sigma techniques to effect reliability improvements — to find out where the most frequent work is done and decrease the amount of work.

“The first phase was about being more effective at repairing equipment,” says Paulin. “The second phase was a focus on monitoring equipment and improving reliability; for example, monitoring man-hours, understanding what is wrong with the equipment so it can be improved, and identifying equipment that requires frequent repairs.

“You can’t improve something you don’t know. Define and measure what you do, measure your performance and analyze your information, such as work orders. When it is all analyzed, look at improvement methods, implement them and make sure they work.”

Take, for example, the mill lube oil system in the Semi-Autogeneous Grinding Mill (SAG), where ore is ground to a fine powder. “When the project was started by Terry Fortune (a Six Sigma black belt), we had 28 days mean time between failures that caused an unplanned shutdown of the SAG mill. When it shuts down, we have no more feed for the main plant. Since the project was started we have had just one occurrence due to the lubrication system after 368 days, and that happened 174 days ago,” Paulin explains.

The mill supervisor, Don McLean, and his team have reduced the unplanned shutdowns of SAG mill systems — conveyors, silo, feeders, pumping system — by 50 per cent, from nine a month to four a month.

Mark Rice (also a black belt) started a production drilling reliability project in 2000. “We had a fleet of 10 MTI downhole drills. Now we have six drills and the maintenance cost per foot drilled has dropped from $3.11 to $1.75,” Paulin notes.

Currently, explains Paulin, “we are trying to integrate the Six Sigma methodology with our equipment maintenance program. We are working on four more reliability projects and have created the position of reliability engineer to help further these goals. There is still a lot of work to do, but many employees have done a lot of work to get where we are since embarking on this road in 1998.”

Carroll McCormick is a Montreal-based writer and regular contributor to Machinery & Equipment MRO.