QUEENSLAND DEPARTMENT OF MINES URANIUM EXPLORATION IN QUEENSLAND, 1967-71 by J. H. Brooks ! „ REPORT No. 69 GEOLOGICAL! SURVEY OF QUEENSLAND J. T. Woods Chief Government Geologist QUEENSLAND DEPARTMENT OF MINES URANIUM EXPLORATION IN QUEENSLAND, 1967-71 by J. H. Brooks ^..•Vi-.V-.-;., REPORT No. 69 GEOLOGICAL SURVEY OF QUEENSLAND J. T. Woods Chief Government Geologist WF * Co W2 TABLE OF CONTENTS Page SUMMARY 1 INTRODUCTION 1 HISTORY OF EXPLORATION I AIRBORNE R2VDIOMETRIC SURVEYS 2 DRILLING 2 RESERVES 4 DISTRIBUTION 6 EXPLORATION 6 Westmoreland 6 Caltor. Hills 8 Paroo Creek 8 Gorge Creek 10 Spear Creek 10 Mary Kathi'een 10 Georgina Basin 11 Georgetown 11 Mesozoic Sedimentary Basins 12 FUTURE OUTLOOK 14 REFERENCES 15 TABLES Table 1 Drilling for uranium in Queensland - annual footages 3 Table 2 Queensland uranium reserves 5 Table 3A Uranium exploration under Authority to Prospect, 1965-71 16 Table 3B Uranium exploration by the Bureau of Mineral Resources 19 Table 4 Drilling for uranium in Queensland - individual deposits 20 FIGURES Figure 1 Areas of Queensland covered by airborne radiometric surveys Opposite 1 Figure 2 Drilling for uranium in Queensland, annual totals 4 Figure 3 Locality plan, uranium occurrences, Westmoreland area 7 Figure 4 Locality plan, uranium occurrences, Mount Isa area 9 Figure 5 Post-Triassic sedimentary basins in Queensland 13 QUEENSLAND SHOWING URANIUM EXPLORATION IN QUEENSLAND 1967-71 by J, H. Brooks Geolot ical Survey of Queensland SUMMARY Exploration for uranium revived in 1967 after a period of little activity, and a peak was reached in 1970, when drilling for uranium totalled 143, 920 feet, and numerous airborne and gronnd ra-iiometric surveys were carried out. Total Queensland reserves ot TJ3O8, in ore with a grade exceeding 21b/ton, are estimated to be 28, 926 short tons. Increases in reserves in the 1967-71 period resulted largely from further exploration of previously known deposits in the Precambrian of north- western Queensland. The largest deposits are in the Westmoreland area, but the only firm plans for production of uranium are at the Mary Kathleen deposit, which is to recommence production in 1974. Extensive explora- tion for sedimentary uranium deposits, mainly in Jurassic and Cretaceous sequences, has not been successful, but there is considerable scope for further exploration. INTRODUCTION This report reviews the period of intense exploration for uranium from 1967 to 1971 and is, in part, supplementary to the publication "The uranium deposits of North Western Queensland" (Brooks, 1960), which is out of print. Information has been compiled from open file company reports and published reports of exploration companies. Some results of exploration on current Authorities to Prospect and Mineral Leases are held by the companies concerned as confidential. The Mary Kathleen deposit has been described by Hughes and Munro (1965), but no recent geological descriptions have been published on the Westmoreland deposits or the Paroo Creek-Calton Hills deposits. HISTORY OP EXPLORATION The first period of uranium exploration from 1954 to 1960 was followed by a hiatus to 1966. During this period the only drilling carried out on uranium deposits were short programmes at the Mary Kathleen mine in 1964, following the cessation of production, and the Monakoff copper-uranium prospect near Cloncurry in 1965. With the projected improvement in market prospects for uranium, interest in exploration revived strongly in 19 67. Mary Kathleen Uranium Ltd launched an extensive drilling p. ?gramme to augment proved reserves at the Mary Kathleen deposit and searched for uranium over a wide area around Mary Kathleen. In the same year several Authorities to Prospect were taken up in northwestern Queensland by Queensland Mines Ltd, Mount Isa Mines Ltd, and The Broken Hill Proprietary Co. Ltd, primarily for uranium explora- tion, and Kerr McGee Australia Ltd extended the search for uranium to the Mesozoic sandstones of the Surat Basin in southern Queensland. The most significant discovery was made by Queensland Mines Ltd in the latter part of 1968, when extensive primary uranium mineralization was found adjacent to previously known occurrences of secondary uranium minerals at Redtree in the Westmore- land area. Drilling has since delineated primary and secondary deposits of uranium con- taining the largest known reserves in Queensland. In the following year the same company located substantial tonnages of uranium lore at the Valhalla prospect, north of Mount Isa, and made a new discover} of potential significance, the Warwai, in the Calton Hills area, north of Mount Isa. l! 2. URANIUM EXPLORATION IN QUEENSLAND, 1967-71 The level of exploration activity in terms of radiometric surveys and drilling was far higher in the 19 67-71 period than in the firat uranium "boom" of 1954-60. Whereas the individual prospector was very prominent in the first uranium "boom", exploration in thel967-71 period was almost entirely by mining companies. Although radiometric surveys have become much more sophisticated in regard to instrumentation, very few entirely new uranium occurrences have been discovered and none of the new occurrences has yet been proved to be of major economic importance. AIRBORNE RADIOMETRIC SURVEYS Prior to 19 67 airborne radiometric surveys were largely carried out by the Bureau of Mineral Resources and by mining companies using scintillometers in light air- craft or helicopters. Since then most of the surveys have been carried out by geophysical service companies using specially fitted aircraft. Companies which have carried out air- borne radiometric surveys in Queensland include Geophysical Resources Development Co., Texas Instrument Inc., McPhar Geophysics Pty Ltd, Air Research Pty Ltd, Adastra Hunting Geophysics Pty Ltd, Air Search Exploration Pty Ltd,' and Canadian Aero Services Ltd. j Other significant developments have been the introduction of multi-crystal gamma ray spectrometers and the use of computer processing to produce automatically plotted isoradiation maps. The ability of the gamma ray spectrometers to discriminate between radiation from different sources has been of distinct advantage in follow up ground work and the spectrometers rapidly received acceptance by exploration companies. In addition to surveys specifically for uranium, several aerpmagnetic- radiometric surveys have/ been carried out by mining companies as part of general ex- ploration programmes over Authorities to Prospect, and by the Bureau of Mineral Resources in connection with regional geological surveys (Bowen Basin, Herberton, Mossman and Cloncurry areas). A gamma ray spectrometer survey was also carried out by the Bureau of Mineral Resources over part of the Georgina Basin in connection with a study of the occurrence of phosphate. r The Westmoreland uranium deposits were found as a result of an airborne scintillometer survey (Livingstone, 1957) and more recent detailed airborne surveys have located additional anomalies which are being investigated. Of the other occurrences of uranium found from airborne radi,ometrie surveys, only the Warwai prospect has warranted extensive exploration by drilling.- ,•="..• > Areas covered- by airborne radiometric surveys are shown on figure 1 and further information is summarized in Table 3. • - DRILLING , , . The total reported footage of diamond core drilling and non-core drilling for uranium in the 1967-1971 period was 405,287 feet. Details are given in Tables 1 and 4. The major programmes were Malry Kathleen (8(4, 438 feet), Westmoreland (Qld Mines 141,599 feet, B. H. P. 20,309 feet), Valhalla (46, 516 feet), Skal (13, 467 feet), and Warwai- Watta (16,032 feet). Annual drilling footage reached a peak of 143, 920 feet in 1970, and showed a marked reduction in 1971, Local factors contributing to this were Queensland Mine* Ltd's tr&nsferral of its major exploration effort to the Northern Territory and the absence of discoveries meriting exploratory drilling. The magnitude of the drilling pro- grammea im elation to the extent of fthe uranium deposits reflects the erratic, distribution of uranium mineralization, necessitating a closely-spaced pattern of drill holes in order to make reliable estimates of ore jreserves. However, the 1967-70 discovery rate of approximately 100 lb U3O8 per foojt drilled (including refractory ores) compares very favourably with ratea in the U.S.A. ((Sherman, 1971). , URANIUM EXPLORATION IN QUEENSLAND, 1967-71 3. TABLE 1 DRILLING FOR URANIUM IN QUEENSLAND - ANNUAL FOOTAGES Footage Year Main Programmes Core Non-core Total 1954 8,722 8,7 22 Mary Kathleen, Skal, Pile, Monakoff 1955 35, 640 - 35, 640 Mary Kathleen, Elaine Dorothy, Ander- son's 1956 4,146 - 4,146 Mary Kathleen 1957 6,107 1,473 7,580 Mary Kathleen, Helafells 1958 6,830 1,208 8,038 Mary Kathleen, Milo, Redtree 1959 30, 466 139 30, 605 Mary Kathleen, Anderson's, Skal 1960 9,666 - 9,666 Mary Kathleen, Anderson's, Skal 1961-63 - - - 1964 8,393 - 8,393 Mary Kalhleen 1965 1,511 1,511 Monakoff 1966 250 - 250 1967 26, 186 119 26, 305 Mary Kathleen 1968 39,459 19,595 59, 054 Mary Kathleen, Skal, Bikini, Elaine Mary, Pile, Future, Mighty Glare, Carol, Surat Basin 1969 84, 048 50, 850 134,898 Mary Kathleen, Westmoreland (Redtree, etc), Valhalla, Skal, Queens Gift, Printi, Eromanga Basin 1970 65,866 ; 78,054 143,920 Westmoreland (Redtree, Long Pocket, etc), Valhalla, Watta-Warwai, Tjilpa, Mirrioola, New Batman, Marraroo, Jurraveel, Yvonne Theresa, Eagle, Elizabeth Ann, Eromanga Basin 1971* 15, 810 25, 603 41,413 Westmoreland, Watta, Surat Basin Totals 343, lffO 177,041 { 520,14 J .! * Provisional figures f 4. URANIUM EXPLORATION IN QUEENSLAND, 1967-71 FIGURE 2 DRILLING FOR URANIUM IN QUEENSLAND 140 ANNUAL TOTALS 130 120 110 - 100 1954 YEAR Drawn by Drafting Branch Department of Mints Briibint M.O. «-7Mt /';\;.<-, •• • ,' '"'. RESERVES „ Prior to 1967; reserve* were 7, 670 short tons U3O8 in the Mary Kathleen deposit and 2, 750 short tons U3O8 in the Slcal and Anderson's lode. Since 1967 extensive drilling-at Mary Kathleen Increased reserves only marginally to 8,726 short tons U3O8 with a further 2,253 short tons U3O8 in low grade ore.