At some time between 11:35am and midday on 4 October 1990, miner Martin Rowlands and nipper Ricky Gudge were replacing a faulty hydraulic hose on the right-hand boom of an Atlas Copco Boomer H128 two-boom jumbo (more specifically identified as MIM Unit No 3521) which was then drilling at the heading of KD51 incline on 9a sublevel in the Hilton mine. Both men were standing between the right-hand or western sidewall and the right-hand boom of the jumbo which was approximately one metre above floor level and the same distance from the sidewall. While they were so engaged a section of the western sidewall slipped off and fell upon them. Rowlands was crushed and held against the boom which Gudge fell to the floor with rocks covering his lower body. Rowlands died at the site from asphyxia and spinal cord avulsion. Gudge suffered a fractured skull and lumbar spinal injuries.
We cannot emphasise too strongly the need for all face persons to be constantly alert for deteriorating ground conditions and the continual need to bar down. This assumes greater importance with the increasing size of development openings. To ensure that a suitable scaling
bar is always available, management should investigate the practicability of carrying such a bar attached to each mobile face unit.
Where it is deemed necessary to install temporary ground support right up to the face of an advancing development heading, procedures should be adopted to minimise personnel exposure to unsecured ground. These include:
Individual split-sets should be placed as soon as each hole is drilled and each ring of support should be completed before proceeding with the next ring closer to the face.
When doing maintenance work on mobile equipment, the unit in question should be positioned under secured ground and adequate space allowed for the work to be performed.
In unravelling ground, smooth wall blasting techniques should be adopted for the sidewalls and the backs to limit the damage to the ground.