SINCE listing on the ASX in late 2007, GBM Resources has acquired a selection of licences and licence applications covering more than 5839sqkm within Queensland and Victoria. The company is committed to exploring iron oxide copper gold (IOCG) style mineralisation at the Brightlands project; a suite of projects held in joint venture with Pan Pacific Copper and Mitsui; and the Bungalien phosphate joint venture with Swift Venture Holdings Corporation.
In March, GBM announced its $5.8 million 2011 exploration program, focussed on advancing these existing targets. GBM allocated $2.5 million to the Brightlands project, $3 million to the Pan Pacific/Mitsui joint venture tenements and $280,000 to the Bungalien
phosphate joint venture. “2011 has been a big year,” GBM managing director Peter Thompson said, “and the programs have been very successful”. Polymetallic IOCG potential: Brightlands The Brightlands tenement area, southeast of Cloncurry in Queensland,
has been the subject of previous exploration by several companies, although historically focus was narrow and did not provide understanding of the larger geological system of the area. GBM’s examination of historical data suggested widespread mineral occurrences with IOCG potential and high-grade Tick Hill-style gold mineralisation.
The 2011 exploration program aimed to build on work from 2010 that provided an initial exploration target of between 30 and 80 million tonnes of mineralised material grading between 0.8 and 1.2 per cent copper equivalent. The program started in early April, with drilling results throughout the year showing copper, gold, silver, molybdenum, cobalt and uranium grades: confirming Milo as a large polymetallic IOCG find in the Mt Isa region. Mr Thompson said many targets within the project showed potential, but the key priority was Milo. The 2011 program extended the Milo mineralisation to the north and west of previous drilling, and the significantly mineralised breccia structure is believed to be open along strike and at depth. GBM hit a significant economic milestone when preliminary metallurgical test work completed in July demonstrated Milo could provide a saleable copper concentrate grading 24 to 27 per cent with recoveries of 75 to 80 per cent. By-product elements including gold, silver, molybdenum and uranium were also found to have favourable metallurgical features.
What GBM didn’t expect to discover was a potential source of rare earth elements within Milo. However, in July a broad zone of rare earth elements and yttrium (REEY) mineralisation was intersected. The dominant rare earth elements related to the mineralisation were lanthanum, neodymium and cerium, with associated yttrium. The REEY zone was open along strike and at depth, and Mr Thompson said GBM would undertake further drilling
to test extension and depth.
“At the moment [we’re] testing the previous holes that we’ve drilled…to assess the rare earth content, so it’s looking pretty positive,” he said. Based on the various REEY in samples analysed to date, GBM determined the value of the mix of rare earths at Milo would have a weighted average value of about US$150/kg, in comparison to the current copper value of $8/kg. Five months of flotation tests were completed in October, and Mr Thompson said that the results of these and other metallurgy tests had given GBM a lot of
confidence in the potential development of saleable copper concentrates from Milo. He added that the tests also showed it would be possible to recover up to 80 per cent of the ore’s molybdenum, more than 90 per cent of its uranium, and 75 to 80 per cent of its gold and silver. “We’ve just recently re-commenced drilling at Milo,” Mr Thompson said in November, “focussing on the northern extension of the mineralised zone”. Continuing positive results from Milo would provide the basis of a scoping study for a proposed polymetallic development, currently planned to start in January 2012, he said.
“Key elements of the scoping study will be to achieve a maiden resource out of Milo and complete work on the rare earths mineralisation which will take us into the next development phase of a pre-feasibility study by mid 2012,” Mr Thompson said. IOCG potential: Pan Pacific/Mitsui farm-in Four GBM project areas covering 1580km in the Mt Isa region of North Queensland – Bungalien/Horsecreek, Grassy Bore/Talawanta, Mount Margaret and Chumvale – are subject to a farm-in agreement with Pan Pacific and Mitsui