Safeguarding mines with strata control

Resin bolts have become an increasingly popular strata control technique that incorporates the use of a chemical adhesive to anchor steel studs into mine walls or ceilings.

The Trajectaflex Resin Firing System, which was developed by Wilco Technologies in South Australia, is a resin capsule installation tool. The system centres around a steel nozzle that is designed to increase the efficiency and safety of resin set bolting cycles. It has been used at a number of mines across Australia and at the Grasberg mine in Indonesia.

Two of the resin-firing systems have now been sent for use at the Oyu Tolgoi mine in Mongolia. It is one of the largest copper mines in the world, with the majority of the value buried more than a kilometre underground.

Wilco CFO Clare Williams said the patented nozzle gave operators the ability to index the bolt hole effectively to install the resin capsules. “Obviously in underground mines strata control is critical, so jumbo operators install the resin bolts and each bolt can hold up to 25 t of rock,” she said.

“The Trajectaflex is a one-man system with less operator movement on and off the jumbo platform, which reduces fatigue and the chance of injury. It eliminates the need for an offsider and makes it easier to load the resin capsules.

The Trajectaflex resin-firing nozzle is a single-pass system that consists of a tension spring with an adapter at each end. It also includes a nylon inner tube and an exchangeable tip. The 800 mm nozzle is set at the end of a rail on a dual boom jumbo, mounted onto an independent slide. This enables operators to drill the hole with one boom while the other boom inserts the resin and the bolt. Each boom can be extended and shortened to make the installation easier.

“The spring is the key,” Williams said. “If the jumbo operator is trying to insert the resin capsules into a 35 mm pre-drilled hole that is four to eight metres away from them, they can flex the spring, which will self-index the nozzle tip into the bolt hole. Then with air pressure, the operator can shoot the resin capsules into the hole they drilled and then insert the bolt.”

The hole can be probed for without damage to the nozzle and there is no need to physically check for correct bolt hole alignment. This process is claimed to be able to save operators up to 40 minutes during bolting cycles compared with the amount of time it takes to insert plastic tubes that are commonly used.

Originally published here.