An occurrence of primary magnetite mineralisation within buried Archaean magnetic basement, first inferred from a strong northeast-trending linear magnetic anomaly observed at a location 20 km south of Ooldea Siding at the northern edge of the Nullarbor Plain, and also found in a diamond drill core cut in the 1985 SA Government stratigraphic drillhole Ooldea 3, is being explored for its possible economic potential. The subject tenement is also considered to be prospective for gold and base metal mineralisation, on the basis of results obtained earlier by Amoco Minerals' exploratory drillhole ORP2 drilled further to the north-west within former EL 616, which had encountered highly metamorphosed and deformed metasedimentary gneiss containing relict banded iron formation, overlain by Cambrian sandstones carrying elevated gold values. Early work undertaken by the licensee Baram Holdings and its joint venture partners Kingsgate Consolidated and Offshore Diamond Mines comprised a review of all available geological and geophysical data, a Landsat imagery and aerial photo interpretation of surface features, with follow-up ground-based reconnaissance, and the re-logging and re-assay sampling of the stored drill cores from the abovementioned holes Ooldea 3 and ORP2, plus mineral extractive metallurgical testing of the magnetite-rich intervals in the Ooldea 3 core. These occupy a 50-60 m thick zone in the core, and had yielded spot assay values of up to 56% Fe2O3 + FeO. Davis Tube mineral separations were performed for the licence operator by the WA Department of Mines' Mineral Processing Laboratory during May 1990, on seven 2-3 m composite bulk samples of the Ooldea 3 cored magnetite mineralisation. These samples were ground to minus 75 microns and yielded a magnetite concentrate up to 40%, but with an unacceptable silica content (24-32%). A sample ground to minus 63 microns yielded a much improved concentrate with a very low silica content of 2.4%, but the magnetite content of the finer ground material was only 20.5%. The re-assaying of ORP2 drill core samples for gold by both AAS and fire assay methods yielded very disappointing values (max. 0.010 g/t Au, vs an average 0.15 g/t over 18 m as reported by Amoco Minerals). Accordingly, the potential for discovering shallow gold or base metal deposits in the Ooldea region was downgraded. The consortium's previous geophysical modelling of gravity and magnetic data collected by the BMR and SADM over the ~65,000 nT target magnetic anomaly had indicated the presence of a steeply eastwards-dipping tabular body up to 1 km wide and extending along strike for up to 20 km. It appeared to persist from about 100 m below the surface down to a depth of >1 km. Computer modelling of the SADM ground gravity and magnetic data collected along a traverse passing through the Ooldea 3 drill site suggested that this drillhole had intersected only the eastern margin of the magnetite deposit, and that higher magnetic susceptibility rocks occupy a large volume further to the west. Detailed airphoto interpretation suggested that some highly sheared units of the Karari Fault Zone may occur as outcrop/subcrop approximately 10 km south-west of the Ooldea 3 drillsite, and therefore it was hoped that a significant proportion of the zone, here possibly also magnetite-enriched, may lie near the surface rather than at 130 m depth as in the SADME drillhole. During July 1990, the joint venturers conducted a 25 line km ground magnetic survey, of 5 lines spaced 500 m apart with readings taken every 10 m, over the above area of structural interest (the 'Baram' grid) located 11 km south-west of Ooldea 3, to try to better define the magnetic anomaly section there. Magnetic intensity values around 3000 nT higher than those recorded at Ooldea 3 by SADME's 1985 Moondrah ground magnetic survey were seen, lending credence to the structural model of a shallowing, magnetite-rich basement being present on top of a horst block at this location, where quartzite float had been observed during the latest traverses. Encouraged by this result, the JV commissioned 3D inversion computer modelling of all the available magnetic data for this region along the Karari Fault Zone, from the Department of Geophysics at Curtin University in Western Australia. This showed that the main 'Ooldea' anomaly after levelling has a relative magnitude of ~6000 nT, reached at its northern end. Thus a conclusion was made that the Mulgathing Complex rocks buried there should contain much more magnetite than those encountered in Ooldea 3 drillhole. Because of the supposed favourable economic implications, and despite having scant factual geological evidence based only on core sample logs, assays and petrophysical data coming from a single drillhole, licence operator Offshore Diamond Mines (ODM) began researching the status of the market for magnetite in Australia, and the engineering requirements for establishing an open pit mining operation at the Baram site to produce 1 Mtpa, perhaps destined for a conceptual hot briquetted iron smelter at Whyalla, and/or to sell as fines for use in heavy media mineral separation plants. An inferred in-place magnetite resource for the entire 25 km long Ooldea anomaly area was calculated from the geophysical data so far obtained, using magnetic susceptibilities converted to ore grade. For a section of the tabular mineralised zone taken down to 100 m depth, the speculative figures derived were a total rock mass of 318.9 Mt containing 96 Mt of magnetite, i.e. an average petrophysical ore grade of 29% Fe3O4. A preliminary feasibility study for a mine having an envisaged 20-year life was also prepared by ODM, with basic costings. By mid-1991, Whyalla Steelworks owner BHP Ltd had become attracted to the development possibilities of any large magnetite deposit which might exist at Ooldea, and that company commenced an in-house review of the resource situation. To confirm the JV's assumptions concerning its postulated large magnetite occurrence, an independent technical review of the data accumulated was commissioned from Martin Resource Consultants based in Perth. Their report concluded that for a 2 Mtpa operation, an average price of $45 per tonne would be needed to yield a yearly profit of $10 million. Thus the deposit was not viable at the current local market price for magnetite concentrate ($38 per tonne ex - Savage River, Tas.). Late in 1991, ODM approached several large companies involved in iron and steel manufacture, with a view to introducing a major partner to assist in developing its purported medium grade magnetite deposit. By mid-March 1992, ODM had moved to acquire 100% ownership of the Ooldea exploration tenement, by buying out the other two joint venture partners' respective 40% and 20% interests. Discussions were begun with Midrex Corp. of North Carolina, USA regarding the possibility of establishing a direct reduction ironmaking (DRI) plant in the Ooldea region, which would use that foreign company's newly invented FASTMET rotary hearth furnace process. The envisaged low capital cost DRI plant could perhaps be fuelled by SA's low grade coal resources (e.g. Lock, Wintinna), as apparently it would have a low electricity consumption and would be flexible in its feed requirements for iron ore fines and pulverised coal. The proponent provided ODM with its proprietary research insights into likely environmental factors, mineral processing plant design and production marketing forecasts as they might apply to the South Australian case, and these are included in this data release. On 30/11/1992, Mineralogy Pty Ltd, an Australian company specialising in the development of large magnetite deposits, entered into a farm-in agreement with ODM to acquire 95% of EL 1620 in the name of its subsidiary firm Cosmo Developments Pty Ltd, and to take over operating the tenement. Mineralogy immediately started to do detailed pre-feasibility studies on the Ooldea magnetite occurrence, now touted as suitable for a potential 6 Mtpa mining operation, and began to assess the outlook for new opportunities where fines production from Ooldea might contribute at a profit to future world magnetite sales. No new field work ensued on the licence area during the following full five-year term of tenure of renewed EL 2047, principally because of delays in obtaining legal rights to gain access onto the ground to perform proposed deposit appraisal drilling (which was originally programmed as being 3 diamond cored holes, and later amended to be 10 RAB holes]. This situation arose due to the national ramifications of the Australian High Court's decisions made in the landmark separate Mabo and Wik Native Title cases raised against the Commonwealth Government. Moreover, due to protracted local political issues and procedural developments associated with organising an effective South Australian process for exploration companies to engage in formal negotiations with aboriginal groups and Native Title claimants, which might lead to agreed land use sharing and compensation arrangements, no negotiated land access settlement with the custodial groups was able to be realised until late October 1998. Thereafter, further impasses in negotiations with the parties behind multiple conflicting Native Title claims still prevented a resumption of field work before the licence came up for advance notice of its third term renewal application during December 1999.