David Champion (David.Champion@ga.gov.au)
Tungsten (W) metal, and its alloys, are amongst the hardest of all metals and has the highest melting point of all pure metals. The combination of its hardness and high temperature capabilities make it desirable for many commercial and industrial applications. Tungsten's range of properties also makes it difficult to substitute with other metals. It occurs as wolframite, which is an iron-manganese tungstate mineral ((Fe,Mn)WO4), and scheelite (CaWO4). The major use for tungsten is within cemented carbides, also called hard metals. Tungsten carbide has a hardness approaching that of diamond and is used for cutting and in wear-resistant materials, primarily in the metalworking, mining, oil drilling and construction industries. Tungsten alloys are used also in electrodes, filaments (light bulbs), wires and components for electrical, heating, lighting and welding applications. Tungsten is used also in chemical applications, including as catalysts, as well as pigments for paints. Ferrotungsten (FeW) is a high value-added intermediate product and is used in steels and alloys where hardness and heat resistance are required. Tungsten is commonly supplied as mineral concentrates typically with 65% or more contained tungsten trioxide (WO3). A number of secondary tungsten compounds are also important. These include ammonium paratungstate (APT), tungsten trioxide (WO3), ferrotungsten (FeW) and tungsten carbide (WC), as well as tungsten metal.
Australia's total Economic Demonstrated Resources (EDR) of tungsten at December 2011 were 376 kilotonnes (kt), similar to resources in 2010 (367 kt75). Australia's EDR are in deposits at Dolphin and Bold Head on King Island in Bass Strait off Tasmania (Tas), Kara and Mount Lindsay in Tas, at Watershed in Queensland (Qld), O'Callaghans, Big Hill and Mount Mulgine in Western Australia (WA) and Molyhil in the Northern Territory (NT). The majority of Australia's EDR of tungsten are within WA (about 61%), with most of this at the O'Callaghans deposit (about 50%), while Tas has 22% and Qld 14%.
In 2011, Subeconomic Demonstrated Resources (comprising Paramarginal and Submarginal Resources) were 12 kt, which is equivalent to 3% of the total Demonstrated Resources. Meanwhile, Inferred Resources decreased slightly from 110 kt in 2010 to 107 kt in 2011. Queensland accounts for 47% of Inferred Resources, followed by WA with 32%, Tas with 11% and New South Wales (NSW) with 9%.
For location of tungsten deposits refer to Fig. 14 in the Tin chapter.
All of Australia's EDR for tungsten are unencumbered.
Joint Ore Reserve Committee (JORC) Code reserves comprise total tungsten in Proved and Probable Ore Reserves as defined in the JORC Code. In 2011, JORC Code reserves of 182 kt accounted for approximately 48% of Accessible Economic Demonstrated Resources (AEDR).
Exploration in 2011-12 was largely within more advanced projects with the emphasis on feasibility studies. These projects are briefly discussed under Industry Developments below. Data on exploration expenditure for tungsten are not reported by the Australian Bureau of Statistics.
During 2011, 27 tonnes of high-grade scheelite concentrates averaging 72% WO3 together with magnetite was produced at the Kara scheelite mine near Hampshire in northwest Tas, representing 15.4 tonnes of contained tungsten. The scheelite and magnetite were produced from skarn within Ordovician limestone adjacent to the contact with Devonian granite. Initial production of wolframite concentrates commenced at both Wolfram Camp and Mount Carbine in north Qld in 2012.
In 2011, world economic resources of tungsten were estimated to be around 3300 kt based on the United States Geological Survey (USGS) data and updated by Geoscience Australia for Australia's resources. According to the USGS, China holds approximately 58% of tungsten resources followed by Russia with 7.6% and the USA with 4.2%. Based on the USGS figures and those updated by Geoscience Australia, Australia has an 11.4% share of world resources of tungsten.
The USGS estimates that world production of tungsten in 2011 amounted to 72 kt compared with 69 kt76 in 2010. China was the major producer with approximately 83%, followed by Russia with 4.3%. USA production was not recorded for confidential reasons. Over the past few years, the Chinese Government has restricted the amount of its tungsten ores that can be offered on the world market by applying export quotas and taxes, favouring instead the export of value-added downstream tungsten materials and products.
The price of tungsten rose dramatically following the global financial crisis from a low of less than US$200 per metric tonne unit (MTU = 10 kilograms) of ammonium paratungstate (APT) in late 2008 to mid 2009 to reach new highs of US$480/MTU in mid 2011. This price increase reflected growth in demand and tightening of supply by China. Prices have eased since to around US$400/MTU in mid-2012, but are still above 2000-10 long term average levels. There has been continued activity at a number of projects, including initial production at both Wolfram Camp and Mount Carbine in north Qld.
In 2011, Metallic Minerals Limited completed its sale of the wholly owned subsidiary, Wolfram Camp Mining Pty Ltd, to the German mining company, Deutsche Rohstoff AG (DRAG), which has given DRAG an 85% stake in the Wolfram Camp tungsten-molybdenum project, 90 kilometres (km) west of Cairns in Qld. In November 2011, DRAG announced it had acquired Tropical Metals Pty Ltd which held the remaining 15% of the Wolfram Camp Mine project, as well as 100% of the Bamford Hill deposit 25 km south of Wolfram Camp, giving DRAG full control over both deposits.
In February 2012, DRAG delivered its first WO3 concentrate from Wolfram Camp. In June 2012, daily production was reported to be about 1.5 tonnes of concentrates a day which was worth about $1 million a month. The Wolfram Camp mine was officially reopened in July 2012 and the company is expecting commercial production from July 2012. The company also announced a planned exploration program at both Wolfram Camp and Bamford Hill and indicated it was targeting a JORC Code compliant resource estimate for Bamford Hill. The most current resource estimate for Wolfram Camp, which was released by Planet Metals Limited in May 2010, is 1.42 million tonnes (Mt) grading 0.6% WO3 and 0.12% molybdenum (Mo) comprising 0.78 Mt at 0.56% WO3 and 0.13% Mo in Indicated Resources and 0.64 Mt grading 0.65% WO3 and 0.11% Mo in Inferred Resources.
Vital Metals Limited's wholly owned Watershed scheelite project 150 km northwest of Cairns in Qld at 30 June 2012 has a Measured Resource of 4.42 Mt at 0.25% WO3, an Indicated Resource of 11.51 Mt at an average grade of 0.24% WO3, in addition to an Inferred Resource of 4.73 Mt at 0.26% WO3, using a cut-off grade of 0.10% WO3, for 50 700 tonnes of contained WO3. In mid-2011, Vital announced it had entered an earn-in agreement with Japan Oil, Gas and Metals National Corporation (JOGMEC) for 30% of the Watershed project by co-funding a definitive feasibility study (DFS) for the project. The DFS is scheduled for completion in late 2012. Once completed the JOGMEC interest will pass to a Japanese-owned corporation which, in partnership with Vital, will take the project into development and operation. Vital predicts construction will begin in 2013 with concentrate being produced in 2014.
Carbine Tungsten Ltd (formerly Icon Resources Limited) has completed construction and opened its tailings re-treatment plant at the Mount Carbine project in March 2012 with the first shipment of 1134 MTU of WO3 concentrate in late June 2012. The company announced that the grade of concentrate produced greatly exceeded expectations from the tailings-recovery feasibility study. The company is hoping for final production of 5000 MTU a month from the re-treatment plant with an envisaged project life of around two years. The tailing dams are estimated to comprise approximately 2 Mt at 0.1% WO3. In September 2012, Carbine Tungsten released an Indicated Resource of 12 Mt at 0.07% WO3 for the low-grade stockpile. The company reports a production target of 15 000 MTU of WO3 in concentrate a month from the low-grade stockpile material. This target assumes a processing rate of 3 million tonnes per year (Mtpa) to the X-ray sorter and a milling rate of X-ray sorter accept of about 300 000 tonnes a year. Based on both test work and results from the tailings re-treatment plant, the company expects a recovery rate of 80% WO3.
Carbine Tungsten has completed a favourable feasibility study investigating the economic viability of re-establishing the Mount Carbine tungsten mine. The study considered both an open-cut, hard-rock resource and processing of previously stockpiled low-grade material, which together would provide a 15 year project life. A result of this study was resource upgrades in June and August 2012, with an Indicated Mineral Resource of 18.1 Mt at 0.14% WO3 and an Inferred Resource of 29.3 Mt at 0.12 % WO3 at a 0.05% WO3 cut-off for 48 kt of contained tungsten beneath and adjacent to the Mount Carbine open-cut mine which closed in 1987. Carbine Tungsten indicated that it considered the Indicated Resource is also a Probable Reserve based on mining 3 Mtpa and a price of US$290/MTU at a cut-off of 0.05%. Carbine Tungsten also indicated it intends to begin construction for the hard rock project in early 2013 and is envisaging production from 2014 of 250 000 MTU a year of tungsten concentrate. The company recently completed a program of five deep diamond drill holes testing the extent of the mineralising system at depth and along strike and dip close to the Mount Carbine Mine with some favourable intersections, including 12.37 metres (m) at 0.133% WO3 from 81 m.
The Dolphin Joint Venture between King Island Scheelite (KIS) and Chinese Hunan Nonferrous Metals Corporation (HNC) to redevelop the former King Island scheelite mine on southeast King Island off Tas was terminated in December 2010. HNC transferred its 50% interest in the joint venture assets to KIS's wholly owned subsidiary, Australian Tungsten Pty Ltd (ATPL). HNC has a royalty of 2% on future project revenue from the project, capped at $3.9 million. KIS has undertaken a DFS investigating both re-treatment of tailings and re-opening the underground mine. Outcomes of the DFS include a planned 10-year mine life from both underground mining and re-treatment of tailings, although it would be 7.5 years if mining was from Dolphin only, producing 3500 tonnes per annum (tpa) of contained WO3 in concentrate. King Island Scheelite reported in May 2010 Indicated Resources for the Dolphin Mine and Bold Head Mine as 8.42 Mt averaging 0.95% WO3 and 2.3 Mt averaging 0.73% WO3, respectively, for a combined total of 96 780 tonnes of contained WO3 at a cut-off grade of 0.25% WO3. Estimates of Probable Reserves were upgraded in August 2011 to 2.69 Mt averaging 1.04% WO3 and containing 27 940 tonnes of WO3. In June 2011, the company also reported Measured Resources for the tailings at the Dolphin Mine at a cut-off grade of 0.08% WO3 as being 2.7 Mt averaging 0.17% WO3, with 459 000 tonnes of contained 4590 tonnes of WO3.
Following completion of a successful prefeasibility study in March 2011, Venture Minerals Limited (Venture) commenced a bankable feasibility study for its Mount Lindsay tin-tungsten (Sn-W) deposit. The Mount Lindsay project is located 15 km northwest of Renison Bell tin mine and 20 km west of Rosebery in western Tas. The prospect is in magnetite-rich (Fe3O4) skarns within the contact aureole of the Meredith granite, which is part of a suite of Devonian granites that are the source rocks for a number of large (Sn-W-Fe3O4) deposits in western Tas and on King Island in Bass Strait. The Mount Lindsay Sn-W deposit has combined resources of 43 Mt at 0.4% Sn equivalent with a 0.2% cut-off or 10 Mt at 0.7% Sn equivalent at 0.45% cut-off. The latter figure includes Indicated Resources of 6.2 Mt at 0.4% Sn and 0.3% WO3. The deposit also includes an iron resource. The bankable feasibility study is expected to be completed in the second half of 2012. Venture completed drilling associated with the feasibility study in late 2011. Highlights from the drilling included 48 m at 0.8%, 30 m at 0.9% and 68 m at 0.6% Sn equivalent at the No. 2 skarn, and 22 m at 1.7%, 12 m at 2.0% and 22 m at 1.2% Sn equivalent at the Main skarn. The company also completed a pilot-scale metallurgical program in August 2012, which demonstrated recoveries of 72% for Sn and 83% for WO3 as well as a high-grade tungsten concentrate of more than 66% WO3. In September 2011, Venture submitted a Mining Lease Application for the company's Mount Lindsay Tin-Tungsten Project.
Frontier Resources Ltd announced in April 2012 that it was divesting its Tasmanian projects and assets into the subsidiary Torque Mining Ltd, with an initial public offering planned for later in 2012. The company continued exploration of its Moina Project area, focussing on the stratiform gold and base metal Narrawa deposit 40 km southwest of Devonport in Tas and on the gold-bismuth (Au-Bi) Stormont skarn deposits 190 km northwest of Hobart, Tas. Exploration in the Moina Project area is targeting mineralisation associated with the Dolcoath Granite, including tungsten and tin. The company previously completed a detailed soil geochemical program over four square kilometres encompassing the Narrawa deposit and identified zones anomalous in tungsten, tin, molybdenum, copper (Cu) and bismuth as well as gold.
In January 2012, Thor Mining PLC (Thor) reported Indicated Resources of 3.8 Mt at 0.29% WO3 and 0.22% molybdenum disulphide (MoS2) and Inferred Resources of 0.9 Mt at 0.25% WO3 and 0.25% MoS2. Resource figures in April 2012 include open cut Probable Reserves of 1.64 Mt grading 0.42% WO3 and 0.13% MoS2 for its Molyhil Tungsten and Molybdenum Project, 250 km northeast of Alice Springs in the NT. Potential development of the project was hampered by the global financial crisis and a decline in international metal prices, which resulted in the company scaling back activities. Thor had signed an off-take agreement with one of China's largest State-owned companies, CITIC Australia Trading Limited, for CITIC to take all of the molybdenum and tungsten concentrates produced from the project but that agreement has since lapsed. The recent increase in tungsten prices has resulted in renewed interest and in mid-2012 Thor completed a positive DFS of the deposit, with a mine life of 4 years based on current reserves.
Hazelwood Resources Limited (Hazelwood) released an initial ore reserve estimate at a cut-off grade of 0.05% WO3 for the Big Hill deposit of Proven Reserves of 18.78 Mt averaging 0.11% WO3 and Probable Reserves of 6.43 Mt averaging 0.11% WO3. Using a cut-off grade of 0.05% WO3, the deposit's Measured Resources are 22.94 Mt averaging 0.11% WO3, with Indicated Resources of 11.95 Mt grading 0.1% WO3 and Inferred Resources of 12.54 Mt grading 0.08% WO3 for a total resource of 47.43 Mt averaging 0.1% WO3. The deposit is part of the Cookes Creek tungsten project located 70 km from Nullagine in WA. Hazelwood is undertaking a definitive feasibility study for the Big Hill deposit, including large-scale metallurgical test work on bulk ore samples, which has demonstrated the ability to produce high-purity tungsten concentrate.
Hazelwood completed an integrated prefeasibility study in 2010 that incorporated its Big Hill tungsten deposit and its jointly owned ferrotungsten project in Vietnam. In June 2011, Asia Tungsten Products Company Ltd (ATC), which is 60%-owned by Hazelwood, completed construction of a ferrotungsten plant in the Vihn Bao district near the Port of Haiphong in northern Vietnam. The plant is production-ready and is expected to have a capacity of approximately 3000 tonnes of contained tungsten in the form of 75%-grade ferrotungsten a year. Production is planned to commence in 2013 but progress has been delayed by funding negotiations, which include finance for the plant start-up. Hazelwood has indicated it plans to develop the Big Hill deposit to provide feedstock for the Vietnam ferrotungsten project. The company announced in mid-2012 that a non-binding memorandum of understanding had been agreed for the acquisition by Hazelwood of the remaining 40% of the ATC Ferrotungsten Project, subject to both shareholder and regulatory approval. Hazelwood also announced that a purchase agreement had been reached with a North American-based supplier for up to 54 tonnes of tungsten concentrate a month, which the company indicates will cover up to half of the required feedstock for the first 12 months of operations. Hazelwood indicated that longer-term supply arrangements would be put in place once the smelter reached steady-state operations.
Hazelwood is also evaluating the Mulgine Hill and Trench deposits of its Mount Mulgine Project which is owned 70% by Hazelwood and 30% by Gindalbie Metals, as a potential additional feedstock source. Hazelwood released new resource figures for Mulgine Hill in March 2011, which, based on a cut-off grade of 0.05% WO3, included Indicated Resources of 10.16 Mt averaging 0.16% WO3 and Inferred Resources of 5.35 Mt at 0.12% WO3 for about 18 000 tonnes of contained W. The company also indicated that 95% of the resource is within 100 m of the surface.
Newcrest Mining Limited (Newcrest) released a maiden ore reserve and revised resource figures for its O'Callaghans polymetallic (tungsten-copper-zinc-lead) skarn deposit about 10 km south of Telfer in WA. The company reported Probable Reserves of 51 Mt grading 0.34% WO3 contained within Indicated Resources of 69 Mt grading 0.34% WO3 and Inferred Resources of 9 Mt grading 0.25% WO3. Mineralisation occurs within a sub-horizontal polymetallic skarn at the contact between the O'Callaghans granite and limestone of the Proterozoic Puntapunta Formation. Newcrest is undertaking a prefeasibility study into the deposit, which is expected to be completed in the 2012-13 financial year. Based on its 2011-12 results, Newcrest is indicating potential development of the O'Callaghans deposit within the next five years, subject to board approval.
At its Tallebung tin-tungsten deposit, 70 km northwest of Condobolin in central NSW, YTC Resources (YTC) has commenced a Right to Negotiate Process under the Native Title Act to obtain access to undertake two deep drill holes aimed at testing targets from a previous resistivity survey (below outcropping mineralisation) and to assist in scoping of the Tallebung system for a potential large tonnage low-grade tin deposit. Previous trenching and drilling by YTC (2008 and earlier) has indicated broad low-grade tin-tungsten-silver mineralisation.
In 2011-12 Thomson Resources (Thomson) undertook exploratory drilling of magnetic targets in four prospects of the Cuttaburra and Falcon projects, spread over an east-west 40 km zone within the southern part of the undercover Thomson Orogen in northwest NSW. Thomson reported that drilling on the four prospects intersected evidence of mineralised hydrothermal systems, including alteration and mineralisation. Two of the targets gave high-grade polymetallic intercepts, particularly Au to 3.7 grams per tonne (g/t) and silver to 113 g/t, as well as Bi to 0.4%, Cu to 0.5%, lead to 1.8%, Sn to 0.8%, W to 0.6% and zinc to 4.25%. Mineralisation is reported to occur as sheeted and stockwork veins up to a metre wide within zones of altered basement rocks of the Thomson Orogen. On the basis of the polymetallic assemblage, along with the presence of granite intersected in one hole, Thomson is suggesting an intrusion-related, gold-style of mineralisation. The company has planned additional drilling to test shallower parts of the mineralisation.
Following release of a resource estimate in April 2008 for the Attunga deposit 20 km north of Tamworth in NSW, Peel Exploration Ltd (Peel) undertook a study in 2010-11 to investigate development options which showed that conditions were favourable for a low-capital expenditure operation. Mineralisation at Attunga occurs within skarns developed at the contact of a lime-rich sequence with the Inlet Monzonite. There was no field activity in 2011-12, but in April 2012 Peel indicated it had begun a review of the Attunga deposit and was seeking potential joint venture or off-take partners.
Carpentaria Exploration Ltd continued work at its Broken Hill tin and tungsten project north of Broken Hill in NSW. The work was carried out at the historic Euriowie and Waukeroo Tin Fields, the historic Kantappa tin mine and the Yanco Glen scheelite (tungsten) deposit, which has an Inferred Resource of 0.83 Mt of 0.21% WO3. In 2012, Carpentaria undertook a drilling program at Yanco Glen to confirm the resource and test possible extensions. Intersections included 11 m at 0.47% WO3 and 5 m at 0.86% WO3 as well as 3 m at 0.15% WO3 in a newly identified mineralisation zone about 1.5 km south of Yanco Glen. Interpretations of drill results are in progress. The company also undertook a mining option study which demonstrated that the Yanco Glen resource has potential for open-pit mining.
Cullen Resources has recently completed three exploration drill holes testing targets in the Doyenwae and Trig Orr prospects of its Minter Project area about 50 km northwest of West Wyalong in central NSW. Target areas were based on previously identified wolfram (tin and arsenic) geochemistry anomalies from soil sampling and prior shallow drilling. The company is targeting tungsten stockwork and vein-type mineralisation associated with granite cupolas of the Silurian Kikoira Granite.
75 Reassessed as 367 kt, down from the previously reported 403 kt.
76 Reassessed as 69 kt up from the previously reported 61 kt.