Sizing equipment for open pit mining – a review of critical parameters

Over the past century, open pit mines have steadily increased their production rate. Larger equipment and new technologies make it possible to mine larger batches of materials in a shorter time. Low commodity prices have forced companies to decrease their unit cost, by using new technologies and improving productivity. In the late 20th century, with companies facing low commodity prices and competing with strong rivals globally, larger equipment with lower unit costs ensured survival. As a result, mine geometry and mining equipment have dramatically increased in size. To date, in terms of productivity, the mining industry continues to adhere to the ‘bigger is better’ mentality. There are indications that this strategy may not always be advantageous. This paper will discuss on-going research into understanding the effects of equipment size on surface mining. The research includes investigation of mine and mill construction and operating costs, mine productivity, mine design, and economic optimisation. It identifies the significant variables that need to be considered and suggests an approach to quantify their impact on the mine. The paper also proposes a new view to mine planning and equipment selection with respect to the sensitivity to equipment size factors.