Location of the Myponga/Wild Dog Uranium mine (1).
(click for the larger South Australian uranium map)
The original uranium mineralisation was discovered in October 1953 by a prospector, W. F. Wenham, who bought radioactive specimen material to the (then) Department of Mines for examination. An immediate inspection was made by officers of the Geological Survey Branch and some sampling carried out. The discovery was made by Geiger counter in an area in which rock outcrop is not good, the lode material being completely obscured by sand and soil. Within a few inches of the surface extremely radioactive secondary minerals were revealed, and preliminary grab samples assayed up to 20% U3O8. A few days later, the same prospector made a further discovery nearly half a kilometre to the north. In this instance, two radioactive nuggets were found in the subsoil which on examination proved to be massive pitchblende enveloped by secondary alteration products.
These two discoveries, which became subsequently the sites of the No. 1 and No. 2 lodes of the Myponga Project, are the first of significance to be made in the Adelaide Hills other than the davidite occurences near Houghton. As an immediate consequence a wide prospecting campaign was undertaken in the Myponga area spreading south to Yankalilla and north to Mt. Compass, using both airborne and manual methods. Public interest was also arosued by the awarding of a 5,000 discovery reward, and many private prospectors combed the area.
No further discoveries have been made.
Following the initial inspections, recommendations were made for testing and a program of open cutting, drilling and shaft sinking was commenced. A departmental camp was established on the site and approximately 3 kilometres of access-track construction undertaken. The project was brought to a close in May 1955.
Overview of Geology
The country rock is composed of Archaean age metasediments, intruded ad altered in places by later pegmatites, with four gneissic rock types distinguishable. Secondary uranium minerals are distributed along joint surfaces and foliation planes in the gneiss country rock. The main uranium minerals are uranophane, gummite, and meta-autonite. There is no associated sulphide mineralization in either lode.Project Development
A major drilling program was undertaken, resulting in a total of 3,000 metres of exploration holes being completed. As soon as sufficient information became available from drilling, shaft sinking was commenced on No. 2 Lode, two shafts being sunk to shallow depths. On No. 1 Lode, following excavation of the near-surface ore, an inclined shaft was sunk following the main pitch of the geological strucure. This was continued to an inclined depth of 38.4 meters. At a depth of 16.8 metres from the portal a drive east was taken for 6.7 metres. At 38.4 metres, shaft sinking was discontinued and a programme of horizontal and vertical exploration carried out.The No. 1 Lode
Sampling from the first open cut revealed showed the average thickness of the mineralized zone to be about 1.07 metres with a grade of 1.33% U3O8. From the shaft that was being excavated, it was shown that the ore was found in vertical geological structures, and consequently horizontal development was undertaken to intersect the ore lodes. However, ore mineralization was not as extensive as hoped for and further samples returned low assay values of 0.47%, 0.96%, 0.24% and 0.10% U3O8.The No. 2 Lode
A total of seven trenches, four diamond-drill holes and twelve wagon-drill holes were completed at the No. 2 Lode. A prospecting shaft was sunk into the richest ore lens to a total surface length of 15.2 metres and a width of 0.6 to 0.9 metres. Uranium ore was encountered at 1.5 metres, and continued for 5.8 metres. The average grad was 1.2% U3O8. Further drilling showed no signs of further mineralization and the shaft was discontinued at 8.23 metres.A second prospecting shaft, 18.3 metres further north of the first shaft, showed spotty uranium-bearing material in small lenses and fragments within the host rock. The shaft was extended to a depth of 11.43 metres and discontinued.
Production
The No. 1 Lode produced a total of 321.86 tonnes of ore at an average grade of 0.37 % U3O8. The No. 2 Lode produced a total of 18.55 tonnes of ore at an average grade of 0.22 % U3O8. The ore was transported to the Port Pirie uranium treatment complex (1) for processing and sale to the Combined Development Agency, the U.K.-U.S.A. military uranium procurement group.The total production from the Myponga Project was 340.41 tonnes at 0.34 % U3O8, giving a total of 1,246 kg U3O8 (2), (3).
Summary - The Obvious Questions ?
Curiously, a map of the area shows that the roads bypass the Myponga area, despite passing along the coast elsewhere along the Peninsula (4). One must ask the question about the risks to the public of uranium mineralization so close to the surface, and only covered by sandy soil with minimal vegetation. Another question that needs to be addressed is the extent of rehabilitation of the area, and the compensation paid to the local Aboriginals and farmers of the area.Given the very low profile that this mine has received, one must wonder why - is it because of a Rum Jungle too close to Adelaide ? Or perhaps another reason ?
If anyone has any more information, please let me know !
courtesy of the Uranium Information Centre
after not knowing of the mine before prompting by me!.
Page last updated - February 7, 1998.
1 - Mining In South Australia, 1982, Compiled by J. F. Drexel, Department of Mines & Energy South Australia, Special Publication No. 3.
2 - Parkin, L; 1957; The Myponga Uranium project, SA Mineral Review #103, pages 46-53.
3 - Nuclear Weapons Proliferation In South Australia; May 1997; The Nuclear Information Centre - Briefing Sheet.
4 - Australia Road Atlas, Hema Maps, 1995.
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