Safe mining practices under wide spans in underground non-caving mines – Case studies

Abstract

Abstract Mining under wide span is of concern as it increases the probability of back caving causing personnel injury and equipment damage in underground mines in open stoping and underhand drift-and-fill methods. Though restricting personnel access to well supported lateral development is commonly practiced, it is not always possible to implement this requirement due to various factors such as ore loss control, drilling equipment limitations, availability of remote operating capacity and consideration of productivity. Even with rules implemented to limit personnel entry into openings with wide spans, the hazards of equipment damage and back caving still exist. Over the years, different practices have been reported and adopted to minimize risks associated with exposure to large spans in various underground mines. Lessons from these practices are beneficial to current and future mines with challenges of safe extraction of thick deposits in a non-caving setting. This paper briefly summarizes practices in mining wide orebodies using the open stoping method without personnel access and underhand mining using the drift-and-fill method with personnel exposure in the industry and presents cases from Kinross mines where the hanging pillar design was tested, and stope backs were naturally and artificially supported for extraction under wide spans using the open stoping method.