Underground ventilation specialist Aquacrete has introduced a new product for rib consolidation in underground coal mines. The Aquacrete OPR2 is applied directly to ribs, effectively replacing meshing in some instances, though is not a substitute for rock bolting.

The versatility and rapid setting properties of the Aquacrete OPR2 product allows formation of structured pillars in conjunction with an overall 'lock in' application to stabilise bad ribs. This method of consolidation reduces the cost in both time and materials to make safe unstable rib conditions.

Used primarily to help with face bolt-up prior to a longwall changeout, the product has been successfully used in various New South Wales mines.

"Longwall lift off and set-up trials have been carried out and have produced both time and dollar savings whilst creating an environment safe to work in. Aquacrete, being white in colour, produces a better and more aesthetic working environment," the company said.

One NSW mine manager said the product had performed extremely well in a trial application and that at next changeout Aquacrete would be applied to the whole face.

Aquacrete national sales and product development manager Stan Nowotny said the installation time is crucial to the longwall lift off program. With cooperation from the colliery to deliver the product to site and the use of trained Aquacrete installers, consolidation of the longwall face is achieved in under two shifts.

Depending on the condition of ribs, a depth of coverage of 30-50mm is usual, with strap pillars every metre apart. Each strap is about 250mm wide, shot blasted in a straight line from roof to floor. The fluted appearance of the Aquacrete rib line also offers security against wayward machine operators and rib burst.

While the technique is not intended to replace rib bolting, at a minimum, shot blasting the rib line with Aquacrete dispenses with the mesh and provides a solid platform for rib bolting, Nowotny said. Additionally, the bolting pattern can be changed to suit the conditions of the ribs.

"The versatility and rapid setting properties of the Aquacrete OPR2 product allows formation of structured pillars in conjunction with an overall 'lock in' application to stabilize bad ribs. This method of consolidation reduces the cost in both time and materials to make safe unstable rib conditions," he added.

Aquacrete has had a presence in NSW for about three years and currently employs 18 personnel from Newcastle.