Extended working hours in shift work and its impacts on productivity, health and safety in South African deep mines

Abstract The increasing mining depth is reshaping the operational realities of South African underground mines. The South African deep-level gold and platinum mining industry operates within a legislated 8h (500-minute) shift system that was historically considered adequate to complete a full daily mining cycle, including drilling and blasting. However, as mines have matured and operations have extended deeper underground with longer horizontal distances to working places, the effectiveness of this shift arrangement has increasingly been questioned. Consequently, gold and platinum mines are beginning to adopt extended working hours to increase the effective hours that underground mine workers work. This study investigates how extended working hours and different shift systems influence productivity, health, and safety performance in South African deep-level mines. To achieve this aim, the study analyses and compares the productivity and fatigue-related safety outcomes between the conventional 8-hour shift and extended 10-hour, 12-hour, and continuous operation (Conops) shift systems. The study also identifies optimal shift patterns that balance production efficiency with occupational health and safety in deep-level mining. It was found that the extended 12-hour double-shift system achieves optimal blast and limits challenges related to lengthy travel time before workers arrive at the work face. The system also aids continuity of operations, which helps achieve efficient operations.