Mineração

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Chapter

2

SURFACE MINING METHODS
REFERENCE:
BULLIVANT, DA. Current Surface Mining Techniques. Journal for the Transportation of Materials in Bulk: Bulk Solids Handling, vol 7, n6, December 1987, pp827-833.

2.1 Ore reserves Suitable for Surface Mining
Ore reserves suitable for surface mining can be classified initially as; Relatively horizontal stratified reserves with a thin or thick covering of overburden Stratified vein-type deposits with an inclination steeper than the natural angle of repose of the material so that waste cannot be tipped inside the pit Massive deposits, deep and very large laterally such that dumping of the waste within the pit is not possible. Of all the variations of surface mining methods available, the three most common methods only will be described here, namely; Strip mining Terrace mining Open-pit mining Figure 2.1 refers to the classification of these methods

2-1

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Figure 2.1

Classification of mining methods

Note how the general classification system works, from stratified (or layered) types of deposits, through the type of layering, the thickness of overburden and finally the means by which overburden is handled; specifically, in-pit or ex-pit systems. A further consideration is the type of material (waste or ore) handling systems that can be used in each type of mining operation, namely cyclic (discontinuous) or continuous systems. Refer to Bullivant’s reference for a description and analysis of the two systems and how they could be applied (and under what circumstances) for each type of mining method considered here.

2-2

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2.2 Strip Mining
Strip mining is ideally applied where the surface of the ground and the ore body itself are relatively horizontal and not too deep under the surface, and a wide area is available to be mined in a series of strips. Typical examples of this type of mining are the larger tonnage coal mining operations in Mpumulanga.