Springvale has a history of poor roof and ground conditions, making it rely heavily on installation of long cable roof support with extensive drilling work with hand-held bolters. Approximately 7,000 cable bolts and trusses are installed every year, equating to 56 kilometres of drilling a year. A large percentage of this drilling is done with hand-held bolters to access the confined spaces where the long cable support is required.
Whilst conventional hand-held bolters are designed to drill small diameter holes and install short roofbolts of up to 2.4m, at Springvale eight metre cables are installed. This has resulted in operator exposure to higher vibration and a higher chance of drill steels jamming which can throw and jar the bolter.
When drilling an operator - through physical strength - must continually balance the hand-held bolter and is exposed to water, drill-fines and falling roof material.
The operator must also manually insert the cable and physically relocate the heavy hand-held bolter.
To address all these issues senior mining engineer Rae O’Brien and senior supervisor Ron Nielson and their team developed the “Truss Master” – a small mobile bolter consisting of a rotary chuck in a fork-lift-style frame. The Truss Master was a finalist in the 2004 New South Minerals Council’s Occupational Health and Safety Innovation Awards.
The Truss Master is on wheels and self-supported and is operated remotely via a flexible umbilical-cord style controls. The friction-grip-guides are used to feed the cable bolt up the hole.
The Truss Master has resulted in reduction in lost time injuries, disabling, occupational overuse (RSI) and fatigue injuries.
When it was first trialled at Springvale in 2003 there was a 40% rise in cable-bolt installation rates compared to conventional hand held bolters. Secondary support was also completed faster.
The Truss Master has now been at use at Springvale for 12 months and at Tahmoor and Angus Place for six months. No injuries or incidents have been recorded with the use of the Truss Master in this time.