Applications of a finite discrete element approach to model block cave mining

Abstract

Stress redistribution accompanied by gravity triggers progressive fracturing and caving of the ore into the undercut. As caving of the ore is initiated, the undercut is connected with the production level by blasting bell-shaped ore passages, termed drawbells or drawpoints (see Figure 1b). The broken ore material falls into the production level through the drawpoints, transported to the crusher and, subsequently, brought to the surface. As broken ore is removed from the drawpoints, the ore above continues to break and cave in by gravity, as illustrated in Figure 1.1(c). As the ore1 GENERAL INSTRUCTIONSBlock caving is one of the most cost effective underground mining techniques, largely relying on managing the forces of nature to extract the ore. Block caving is typically employed to mine massive low grade copper, gold and molybdenum mineralization and diamond-bearing kimberlite pipes. High efficiency and low production costs coupled with ever growing demand on natural resources are making block caving method increasingly important for the mining industry. A general block caving mine layout is shown in Figure 1(a), typically consisting of two mining levels (production level and undercut level) placed within the ore column. The ore material is mined sequentially in largematerial is extracted, caving progressively extends upwards, potentially causing a significant surface depression, or subsidence crater, above the undercut and in the adjacent areas.