INVESTIGATION OF UNPLANNED DILUTION IN OPEN STOPING MINING METHOD: A CASE STUDY OF THE RIDDER-SOKOLNY MINE

Abstract

The open stoping mining method is considered as one of the most common mining methods for steep orebodies due to its several advantages. However, open stopes are susceptible to unplanned dilution. Dilution can jeopardize the profitability of the mining operations because it increases the production cost. This has been the case in the Ridder-Sokolny mine, where large amount of unplanned dilution was observed. The thesis is aimed to characterize the unplanned dilution experienced in the Ridder-Sokolniy mine and to develop an alternative open stope design tool to the conventional ELOS graphs used in that mine. Unplanned dilution data and design parameters of 107 stopes were collected. Firstly, the performance of the ELOS method was evaluated. Next, the multinomial logistic regression model was implemented to derive probabilistic charts relating the unplanned dilution and its two key influencing factors. The results showed poor to fair agreement with the actual unplanned dilution with the ELOS method. Therefore, this design method is not reliable for unplanned dilution in Ridder-Sokolny mine. On the other hand, the proposed charts indicated that the generated probabilistic map provide desirable accuracy of 63% for estimation of unplanned dilution in stopes. It was concluded that the multinomial logistic regression charts could be used to design open stopes as they can assist in selecting the stope dimensions that would minimize unplanned dilution.