EVOLUTION OF CEMENTED ROCK FILL AT MOUNT ISA MINES LIMITED

Abstract

Mount Isa Mines Limited has used Cemented Rock Fill (CRF) since 1973 to fill voids within the copper orebodies where pillar extraction is an integral component of the overall extraction sequence. To date, 64 million tonnes of CRF have been placed into 173 stopes, containing on average, binder contents of 1.3% cement and 2.6% copper reverberatory furnace slag. Multiple exposures of fill masses in excess of 200m high and 40m wide have been created with minimal fill dilution in the ore. Development of CRF as a cost effective engineering material has been achieved as a result of considerable research effort, motivation to pursue increased fill performance and sound stope design aimed at minimising risk in the advent of poor fill performance. This paper describes the evolution of CRF at Mount Isa Mines Limited. Consideration is given to understanding of in situ structural characteristics of CRF and describing the research and development undertaken to produce an efficient filling strategy using CRF. An in situ transportation model for CRF is described.