Modern Quarrying July-August 2015

FACE TO FACE WITH ASPASA

across the entire section, which deter- mines the overall utilisation you are get- ting out of crusher. Reputable companies will be able to look at a liner and tell you the effectiveness of crushing taking place and be able to develop liners to address inefficiencies.” Active representation Pienaar has once again been appointed to the executive council of the Chamber of Mines, and is also involved with the MHSC which is chaired by the Chief Inspector of Mines. This tripartite body comprises the unions, the state and employers. Pienaar is an alternative on the Council, chairperson of the HR Committee and an alternative on the MRAC Committee, which oversees draft legisla- tion as it comes in from the various task teams. Aspasa is more than a voice for industry; it champions the interests of its members and Pienaar says the issues it is fighting for are aimed at providing a sustainable, responsible and professional industry. MQ

be choke fed for optimum performance. It is therefore vital that feeders and screens deliver the right amount of materials to the crushers at all times. Moisture should also be kept to lower than 5,0%, fines and the use of water minimised to avoid wear on liners from the bottom. If you screen right, your crushing is right,”Fletcher says. It is always advisable to run a plant at 100% for less time, rather than running it on trickle feed for a long period of time, as the lowmaterial levels may cause damage to the crusher. Any crusher works better when full. Equally important is the selection of the right type of liner with the right type of profile to feed materials and ensure the correct movement within the process. Depending on the application there are coarse to fine profiles that can be speci- fied to meet crushing requirements. According to Fletcher, maintenance staff should monitor the wear pattern regularly to ensure it is even from top to bottom and also ensure that the liners are replaced at 25-40% of their thickness to prevent damage to the machine. “They should also look at the wear pattern to ensure crushing is taking part

Report and photographs by Dale Kelly

Regulation 292 in which speed limits will be reduced to 40 km/h in urban areas, 80 km/h outside urban areas and 100 km/h on highways, where they pass through urban areas, is also being challenged. The objection raises the point that heavy vehicles cannot operate within their optimal efficiency at 40 km/h with a load and tend to overheat.

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MODERN QUARRYING

April - May 2015