Published in the March 2011 Australian Longwall Magazine

Demand for variable speed drive technology is growing, while higher motor power requirements are increasingly requiring the use of medium voltage drives underground.

Longwall mines are seeking a variable speed option of conveyors dependent on load, plus higher reliability and less maintenance.

Wider belt widths and lightweight structures are in demand.

Mines also want rapid development and retraction of conveyor equipment and structure.

ACE director and mechanical engineer John Clack said all of these trends form the basis of the company’s equipment design philosophy.

As for possible oversights made by longwall mines, these can include when sites make inaccurate specifications and surveys.

Another issue is when conveyor design specifications are rated on a higher continuous output when compared to longwall continuous capacity.

There can be problems with installation standards at mines and with overly ambitious delivery periods expected for conveyor equipment.

Some longwall mines can fall into strife if management does not place enough importance to their conveyor systems.

“All mines have a specialist longwall engineer but not all mines have a specialist conveyor engineer,” Clack said.

ACE has commissioned conveyor systems up to 6600 tonnes per hour with conveyor lengths up to 9000 metres and installed power of up to 7000 kilowatts.

The underground and surface conveyor specialist also provides VSD and controlled start transmission substation starters. Since the formation of the ACE Conveyor Group in 2007, ACE has completed a number of large projects.