Abstract
Mining organisations find block cave mining favourable due to being low on operational cost as well as the ability to extract low-grade orebodies. This method comprises various development phases, which commence with the undercut blasting to initiate caving and the subsequent extraction of ore through drawbells in the production level. Block caving also enables the mining of large orebodies with weaker surrounding rock mass. Over time, the presence of large boulders register in the drawpoints, with potential to reduce cave availability. Other considerations for choosing block caving include the need to satisfy safety and production requirements and minimal blasting only limited for the treatment of hang-ups. Hang-ups cause high frequency of idling draw-points that disturb the flow of ore, which require treatment to reduce delays through the function of the Secondary Breaking Unit (SBU). The requirements for SBU include the prioritisation of critical draw-points by ensuring an effective draw control to improve cave availability and to minimise waste ingress. This research study aims to investigate strategies to employ in order to improve cave availability and production performance. The data collection process for the research includes the collection of the real operational data from the mine that covers eighteen months between January 2017 and June 2018. Data collected involves the Load Haul Dump and production data in terms of monthly tonnages. The process also includes the collection of overall loading and hang-up equipment performance. The criteria is on obtaining consistent data longer than six months for analysis. For the comparative and correlational analysis, this study adopts the Pearson’s correlation coefficient. The other considerations involve outlining major contributing factors to low cave availability to determine factors to improve. Once the factors are outlined, the strategies are formulated based on the available literature to determine consistency with the current mine. The results indicate that there is no correlation between improvements in the loading equipment availability and production performance if the other variables remain constant. Focusing on increasing loading equipment as a sole determinant to improve production performance is inadequate. The second main finding indicates two major contributing factors to low cave availability, which include hang-ups and rehabilitation work. The last finding indicates two strategies to improve production performance, which involves the effective treatment of hang-ups and the minimisation of dilution in the ore.
M.Phil. (Engineering Management)