The Impact of Scattered Mining on Gold Recovery: A Case Study in the Deep Level Gold Mine, South Africa

ABSTRACT: Mining at depth presents significant challenges, particularly rockbursts, which threaten infrastructure, production, and profitability. This seismic events compromise ground stability, reduce accessible ore, and lead to mine closures, shortening mine life. A once-profitable mine faces declining production, increased seismicity, and reduced blasted square meters, forcing a shift to lower-grade secondary reefs. Seismic damage has rendered high-grade areas inaccessible, disrupting the business plan. A 16-month analysis of mine plans, production data, seismic mechanisms, and rock engineering designs reveals that seismic events (M ≥ 2.5) primarily result from stress changes affecting pre-existing weaknesses. Consequently, approximately 50% of planned working areas are irrecoverable, severely impacting ore reserves. Enhancing rock engineering designs and monitoring programs is essential to mitigate seismic risks and optimize recovery. By addressing mining-induced seismicity and implementing effective ground response strategies, the mine can extend its life and maintain sustainability despite reliance on lower-grade reefs.