Optimised Open Pit Design Using Minessight Software - A Case Study at the Bisha Mining Share Company, Eritrea East Africa

Abstract

This study investigates the optimization of open pit design using the Lerchs-Grossman (LG) method within the Minesight Economic Planner software, focusing on the Volcanogenic Massive Sulphide (VMS) orebody at the Bisha Mining Share Company in Eritrea, East Africa. The primary objective is to develop an optimized pit outline that ensures both profitability and safety, considering geological, geotechnical, and economic factors. The research employs a systematic methodology encompassing literature review, comprehensive data collection, and iterative pit optimization and design processes. Key inputs include geological data, geotechnical parameters, and economic variables such as fluctuating metal prices. Geotechnical assessments by BGC Engineering provided critical insights into slope stability and rock mass characteristics, essential for safe pit design. The LG method facilitated the generation of optimized pit shells, which were refined to produce detailed pit designs incorporating practical mining considerations. Results indicated an optimized pit containing 28.31 million tonnes of ore with significant grades of gold, silver, copper, and zinc, with a minimal deviation of 2% from the detailed design. This study underscores the efficacy of integrating advanced computational tools and multidisciplinary data in open pit optimization, demonstrating the approach's robustness in achieving feasible and profitable mining operations. The findings also highlight the importance of dynamic economic modeling and continuous geotechnical evaluation to adapt to market fluctuations and ensure long-term operational stability. This research contributes valuable methodologies and insights for the mining industry, promoting enhanced efficiency, safety, and sustainability in open pit mining practices.