The subject quarterly reports record primarily the progress and results of surface and underground exploratory drilling designed to define the Olympic Dam orebody. Further brief comments are provided about the establishment of mining and mineral processing infrastructure, and updated locational plans are included for the activities/features mentioned. During the period of maximum appraisal activity, from early 1981 until mid-1984, up to 13 surface diamond drilling rigs and five underground diamond drilling rigs, working 2 shifts/day, were in use. Geological logs for the resulting drillholes are reported herein, and significant mineralised intercepts that were found are summarised. The Whenan Shaft, sunk at the position of surface drillhole RD100, was excavated to a total depth of 500 m over the period December 1980 - August 1982. After its completion, a campaign of underground exploratory drilling began in May-June 1982 from platforms established at the -420 m level in the shaft. When a sufficient amount of drillhole information about the orebody had been collected by this means, underground drive development was begun in early 1984, initially starting from the -320 m and -380 m levels in Whenan Shaft, and proceeding southwards from the shaft into a part of the deposit where high gold values had been indicated in raw assay results of diamond drill cores recovered by surface drilling. At the same time, following on from a site preparation and build phase that commenced in July 1983, a newly commissioned 5 tonnes/hour metallurgical processing pilot plant was used to test treat bulk parcels of copper-uranium ore extracted from the underground development openings. The pilot plant ran initially for ten months, from February to November 1984, producing 509 dry tonnes of copper concentrates from the grinding and flotation circuit, which were shipped to Finland to undergo smelting trials. In August 1984, an on-site Sirosmelt furnace was also commissioned to produce trial products of matte and blister copper. From early 1985 onwards, underground development driving at Olympic Dam was focussed on providing access to rich copper-uranium ore zones that had been defined at some distance to the north-west of Whenan Shaft, as well as continuing to drive acess tunnels into the southern gold zone. From the middle of 1985 onwards, copper concentrates produced by the restarted pilot plant were upgraded in a newly completed uranium leaching and reflotation circuit, to investigate optimum ways of reducing the uranium content in the feed concentrates that would be destined for smelting, and thus allow the WMC to produce a commercially acceptable copper metal output. At this time, the primary flotation circuit tailings were still not being processed to extract any uranium. During March 1986, excavation commenced of a transport portal for a service decline (road) from the surface, starting from a site located immediately to the north-west of Whenan Shaft. The decline was intended to connect the now extensive underground workings (with the shallowest being at the -260 m level) with the existing surface installations. At about this time, construction of surface facilities for the WMC's planned first stage full-scale mining and ore treatment operation was also commenced.