The Olympic Dam mining operation is some 520 kilometres NNW of
Adelaide on the Roxby Downs Pastoral lease. The deposit containing
copper, uranium, gold and silver was discovered in 1975 by Western
Mining Corporation (WMC). A joint venture was formed in mid-1979
between WMC (51 per cent) and British Petroleum (BP, 49 per cent) for
the development and exploitation of the deposit. WMC assumed 100 per
cent ownership after acquiring BP's share in early-1993. Ore is won from
a highly mechanised underground mining operation and processed to
refined products. Current annual output from the mining of 3.0 Mt of ore
is approximately 83 500 t of refined copper, 1400 t of uranium oxide, 750
kg of gold and 12 000 kg of silver. Conventional long hole, open stoping techniques are used to extract the
production ore. Since stope production began in April 1988, full surveys
and appraisals of stopes have been carried out to evaluate the integrity of
the design and blasting techniques. This evaluation included the
determination of the degree of dilution or non break that had occurred.
Performance information also made it possible to re-design any adjacent
stopes to retrieve remaining ore and conversely, avoid the chances of
targeting backfilled material in the future. Performing stope surveys proved not only to be a time-consuming
process but one fraught with access and line-of-sight problems.
Occasionally it was not possible to obtain any stope survey data, and as
was often the case with the mine pass system, rarely. In 1992 the sudden
failure of the pillar between the fine ore and mullock passes and the
subsequent delays to production, emphasised the need to effectively
monitor pass wear. Initial information regarding the development of the
Cavity Measurement System (CMS) prototype (Figure 1) indicated that it
had the potential to solve these problems by the introduction of a remote
scanning device into a cavity. Following a great deal of investigation, Olympic Dam Operations
purchased the first CMS in Australia. This paper discusses its application
for all underground void surveys and the procedures developed to manage
both field and office requirements.