Authors: W. Swanepoel, R J Thompson
Paper submitted to the South African Institute of Mining and Metallurgy Journal - Transaction papers, January 2004
Abstract
In surface mining operations, waste stripping contributes a significant percentage to the total production cost and it is important to utilize the best technology available to reduce this cost component to an absolute minimum. Depending on the ore-body geometry, this can be done either by reducing unit costs through the utilisation of larger equipment and incorporating the equipment dimensions into the pit geometry, or conversely, by reducing the stripping ratio by employing smaller equipment to realise improved ore recovery and applying the design parameters applicable to such equipment such as narrower road widths and steeper haul road gradients.
This paper examines the influence of bench height and equipment selection on effective mineral resource utilisation. Initially, conventional mine planning wisdom is reviewed, with special emphasis on optimising resource utilisation. The concept of financial materiality is introduced as a means of classifying the resource as either a massive or selective deposit, following which equipment selection for selective mining is characterised. The question of whether or not lower operating costs always add value in the long term is examined for the Kumba Resources Thabazimbi iron-ore mine. The effect of selectivity in the loading action is simulated in a 3D environment over a range of bench heights and the net result in terms of resource utilisation and net present value determined.
