By Sam de Beer
John Gaisford’s article on the role of Land Cruisers in the prospecting and exploration side of the mining business (SA4x4 June 2017) parallels my experience of Land Cruisers as workhorses. I have been involved in underground mining for more than 40 years. In Canada and Australia, I worked at open pit mines and underground mines that used wheeled and tracked vehicles for operations. Every underground mine has an adit (from Latin aditus) where you enter the mine, and then you drive in a spiralling tunnel and long straight ramps, up or down, to the work places. Once you arrive at your workplace, you park your vehicle in a safe place (i.e. where it won’t be run over by a bogger or an underground truck), take your equipment to the fresh rock face, and start your work. A pinch bar is used to bar down loose rocks to make the face safe. After you have washed the face down with pressurised water, you map and sample the face and take an ample number of samples. The hoses, ladder, pinch bar, hammers, sample bags, laptop computer, buckets, tape measures, survey devices, etc. are put on or returned to the back of the vehicle, and then you are off to another face to repeat the process.
The underground roads are really rough, especially as you get closer to the faces. Covering the “road” are big loose rocks – some as sharp as knives, and others with points like spears − which can be very tough on man and machine. The tyres take a beating, so every vehicle carries two spare tyres, just in case. There is always water pouring out of fissures and drill holes in a mine, creating huge pools of both water and mud all the way. This water and mud can be quite corrosive, and every vehicle must be washed every day, after every shift, with a pressure- or steam washer at a wash bay. Every vehicle goes for a service every week; if your vehicle arrives at the workshop and the mechanics find mud underneath it, there is hell to pay.
Tyres used on these underground vehicles are always cross-plies, and the tyre pressure is quite high. The radial tyres that were tested, some of them in the top end of the market, never made the grade – the rubber was too soft, so the sidewalls were punctured and the tyres lost their knobbies on the rough rocky roads in the pits and underground.