LOAD & HAUL
undertake, whether for loading, blasting safety, etc. Other broad-based and high-capacity unit manufacturers include Komatsu and Joy Global . Since mergers the latter offers the P&H range of five wheel loaders from the L-950 up to the L-2350. Tese are designed for four or five optional passes to load dump trucks of 91-360 tonnes. Te L-2350 the largest wheel loader in the world and is manufactured by group company Le Tourneau, which Joy acquired in 2011. It is designed mainly for the lower density product of opencast coal mining. Komatsu manufactures and range of 33 models of medium and large wheel loaders up to the ‘Mountain Mover’ WA1200-3, which is claimed to have the largest bucket in its class at a standard 20m3. It has 1165kW of power and an
operating weight of 205 tonnes. Largest in the Kawasaki range is the 135ZV-2 with a maximum rock bucket capacity of 9.7m3, and high-lift versions available. Fuel/energy economy are increasing
importance in all mobile equipment in mining but perhaps the great variations in power requirements in wheel loaders from idling to breakout and lifting, make optional control particularly important. Similarly manufacturers have incorporated tyre wear control measures into the more sophisticated systems such as maximum wheel speed control and maximum traction control. Even so, if the material and floor comprises abrasive or sharp particles then the fitting of protective tyre chains, particularly the drive wheels, could be advisable.
therefore flexibility of use. General negative factors can include limited breakout force for digging into compact piles, whether blasted or not, and the care required to limit tyre wear where working with and over sharp rock fragments. Whatever means of excavation and loading is chosen the unit’s bucket must suit the material being handled, including maximum handling mass and volume. Ideally the loader bucket would fill the means of transport, usually a dump truck, in a whole number of passes. Caterpillar, publishes a checklist of the many factors applicable to the choice of
30 INTERNATIONAL MINING ENGINEER
method and model of excavator/loader according specific mine operations. Tis is just for guidance, depending on the advice of a Cat dealer. Factors to be considered include the loading area to be covered (including multiple locations), the condition of the material to be handled (fragmentation, digging required, etc), the bench/face height, the angle of repose of the material and any cleaning up required, whether the working floor is uneven and it firmness, the traction possible on the floor and whether its material is sharp, the digging horizon and location(s), and the amount of travel the unit may have to
Komatsu’s largest wheel loader is claimed to offer increased power with lower operating costs, including a dual-mode hydraulic systems for standard or high-power loading
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