Ridgeway Gold Mine (RGM) is an underground sublevel caving (SLC) operation that is owned and managed by Newcrest Mining Limited (NML). Production drill and blast practices are critical to the success of the SLC method at RGM. SLC production ring precharging was introduced in November 2001 to enhance these practices and deliver safety, productivity and cost improvements._x000D_
Current precharging practices require up to two rings to be loaded ahead of the ring to be blasted in each drawpoint. The explosive may be required to remain in the up-holes for periods of four weeks or more prior to blasting. During this sleep' time it is subjected to repeated shock from the blasting ofadjacent rings and from rings in adjacent drawpoints. The project described in this paper was designed to gain an understanding of the factors affecting explosive performance in the precharging environment and to develop explosive products and operating practices that would meet RGM's requirements in terms ofsaf ety, reliability and blast outcomes._x000D_
Several months oflaboratory and field testing were required to characterise the explosive and quantify the effect of post-loading blasting shock. These results were used to determine the most appropriate loading and sleep time criteria for RGM's precharging practices. In addition, the information is being used to guide the development of the next generation of emulsion explosives for use in underground precharging operations._x000D_
FORMAL CITATION:Wiggin, M, Trout, P and Macaulay, B, 2005. Solving the problems of precharging sublevel caving rings at Ridgeway Gold Mine, in Proceedings Ninth Underground Operators' Conference 2005, pp 81-90 (The Australasian Institute of Mining and Metallurgy: Melbourne).