Molybdenum

David Champion (david.champion@ga.gov.au)

Roy Towner (roy.towner@ga.gov.au)

Molybdenum (Mo) is used mostly in steels and superalloys to enhance strength, toughness, thermal and corrosion resistance, and to reduce brittleness. Applications include high speed steels, stainless steels (especially to increase corrosion resistance), high temperature steels and in cast iron. It is used also in nickel, titanium and molybdenum base alloys for applications requiring high strength and stability at high temperatures such as heating elements, radiation shields, glass melting equipment and in jet and rocket engines. Other uses include as catalysts, lubricants and pigments, as well as applications in the electronics industry and as trace nutrients in fertilisers. The main commercial source of molybdenum is the mineral molybdenite (MoS2) but it is found also in minerals such as wulfenite (PbMoO4) and powellite (CaMoO4). Molybdenum is mined as a principal ore but is more commonly recovered as a by-product or co-product from copper and tungsten mining.

Resources

Australia's Economic Demonstrated Resources (EDR) of molybdenum decreased from 324 kilotonnes (kt) in 2010 to 167 kt in 2011. This decrease results from the reclassification to Paramarginal status of 220 kt of reserves at the Spinifex Ridge Molybdenum-Copper Project deposit in Western Australia (WA) which the owner, Moly Mines Limited, indicates is not currently economic. Spinifex Ridge is Australia's largest molybdenum deposit. The reduction in Australia's total EDR was partly offset by increases in new economic resources at Aeon Metals Limited's Whitewash Project in Queensland (Qld) and Dart Mining's Unicorn deposit in Victoria (Vic). The majority of Australia's EDR is in Qld with 87%, followed by Vic with about 9% (57% in WA, followed by 38% in Qld, if the Spinifex Ridge Molybdenum-Copper Project resources are included). Prior to 2011, the majority of Australia's EDR was in WA (Spinifex Ridge deposit).

Australia's Subeconomic Demonstrated Resources (SDR) accounted for about 88% of the total Demonstrated Resources, with 75% of SDR in Qld and the remainder in WA. In 2011, Paramarginal Resources and Submarginal Resources stood at 1220 kt and 0.5 kt respectively.

Inferred Resources of molybdenum increased from 514 kt22 in 2010 to 562 kt in 2011, largely as a result of increased resources at the Anthony deposit in Qld. Queensland and WA account for 65% and 28% of Inferred Resources respectively.

Accessible EDR

All of Australia's EDR of molybdenum is accessible.

JORC Reserves

Joint Ore Reserve Committee (JORC) Code reserves comprise total molybdenum in Proved and Probable Ore Reserves as defined in the JORC Code. In 2010, JORC Code reserves of 220 kt (unchanged from 2009) accounted for approximately 68% of Accessible Economic Demonstrated Resources (AEDR). All of these reserves were from the Spinifex Ridge Molybdenum-Copper Project deposit in WA. As reported by Moly Mines Ltd, the current molybdenum price makes this deposit uneconomic, resulting in the JORC Code reserves for 2011 being zero.

Exploration

Data on exploration expenditure for molybdenum are not available nationally.

Production

There was no molybdenum production in Australia in 2011.

World Ranking

According to United States Geological Survey (USGS) data, updated by Geoscience Australia for Australia's resources, world economic resources of molybdenum in 2011 are estimated to be about 10 100 kt with China holding 43% of the resources followed by the USA with 27% and Chile with 12%. Australia accounts for just over 1.5% of the world's economic resources of molybdenum.

The USGS estimates that world molybdenum production in 2011 amounted to 250 kt compared with 242 kt in 2010. China, the USA, Chile and Peru accounted for about 86% of global outputs in 2011 with China producing 94 kt, followed by the USA with 64 kt, Chile with 38 kt and Peru with 18 kt.

Industry Developments

World molybdenum prices soared in 2007, reaching a high of US$38 per pound (lb) in September 2008 from a low of about US$5/lb in 2001. After the global financial crises in October 2008, the averaged price declined sharply to US$8/lb and continued at that level through the first half of 2009. This led to a tightening of global supplies as many companies ceased operation. However, increased demand from China, Japan and Korea resulted in prices increasing, with the average price for the second half 2009 to early 2012, fluctuating from US$14 to US$18/lb. Since then, prices have eased to below US$13/lb in mid 2012.

Ivanhoe Australia Ltd's (Ivanhoe) Merlin molybdenum-rhenium (Re) deposit, approximately 100 kilometres (km) south of Cloncurry in northwest Qld has progressed through scoping, pre-feasibility and feasibility studies. Outcomes from the feasibility study, which was completed in April 2012, included a mine life of 15 years with a throughput rate of 500 kt a year (with a processing plant located at the nearby Osborne Mine), and an average production of 5100 tonnes of molybdenum and 7300 kilograms of rhenium a year for the first seven years. The feasibility study was based on an April 2012 upgrade of Probable Reserves to 7.1 million tonnes (Mt) at 1.1% Mo and 18.1 grams per tonne (g/t) Re for a contained 78 kt Mo and 129 tonnes Re. Indicated Resources are 6.7 Mt at 1.39% Mo and 23.4 g/t Re with contained 93 kt Mo and 157 tonnes of Re. Probable Reserves are included in the Indicated Resources.

The Merlin deposit consists of high-grade molybdenite mineralisation within the faulted basal metasediments of the Kuridala Formation in the Mount Isa eastern succession. The molybdenum mineralisation is overlain by discrete copper- and zinc-rich polymetallic sulphide zones of the Mount Dore ore body. The Merlin deposit is the world's highest grade molybdenum and rhenium deposit with very high-grade molybdenum mineralisation close to the surface at its southern end in the Little Wizard deposit. The company reported an Indicated Resource for Little Wizard of 15 000 tonnes grading 6.49% Mo, 83.9 parts-per-million (ppm) Re, 2.3% copper (Cu) and 25 g/t silver (Ag). Ivanhoe commenced construction of a decline at Merlin in late 2010 and reported that phase 1 was completed in early 2012. In late 2011, a cross-cut off the decline provided access to the Little Wizard ore body. Phase 2 of the decline development is awaiting project approval. Ivanhoe has been investigating strategic partnership options to secure long-term funding needed to progress development of Merlin and its other projects in the Cloncurry area.

Syndicated Metals Limited (Syndicated) announced a new farm-in and joint venture agreement with Cerro Resources NL in May 2011, giving Syndicated a controlling interest and management of the Kalman molybdenum-rhenium-copper-gold (Au) project, with rights to earn an 80% interest. The Kalman project is hosted by calc-silicate rocks of the Corella Formation within the eastern succession of the Mount Isa Inlier, around 60 km southeast of Mount Isa in northwest Qld. The deposit has Inferred Resources of 60.8 Mt at 0.05% Mo, 1.19 g/t Re, 0.32% Cu and 0.15 g/t Au, with a contained 30.4 kt of Mo. A total of 27.3 kt Mo occurs within an identified internal molybdenum domain of 24.9 Mt at 0.11% Mo and 2.78 g/t Re. Syndicated undertook drilling in late 2011 as part of a planned update of the Kalman resource model which will be used as a basis for an economic evaluation of the deposit.

Aeon Metals Limited (Aeon, formerly Aussie Q Resources Limited) continued exploration for porphyry copper-molybdenum mineralisation in its Rawbelle tenements near Monto, Qld. Focus was on both the advanced Greater Whitewash Project, comprising the Whitewash, Gordon's, Whitewash South and Windmill Hill molybdenum-copper deposits, and their copper-molybdenum exploration projects John Hill and Kiwi Carpet. The deposits of the Greater Whitewash Project occur within a 5 km corridor along strike of each other. The deposits have a total JORC Code compliant resource of 242 Mt grading 258 ppm Mo, 1173 ppm Cu and 1.54 ppm Ag, including Indicated Resources of 185 Mt grading 263 ppm Mo, 1189 ppm Cu and 1.55 ppm Ag with a contained 48.5 kt Mo. Mineralisation in these deposits occurs as veins within a molybdenum-copper porphyry system confined within granodiorite. In October 2011, Aeon lodged a Mineral Development Licence for the Greater Whitewash Project, which it expects to be granted in the second half of 2012. The company have undertaken favourable metallurgical testing with good recoveries of molybdenum, copper and silver. The John Hill and Kiwi Carpet copper-molybdenum targets are approximately 10 km along strike from the Greater Whitewash Project. Aeon is continuing drilling at the John Hill Project, with indications it has identified a large porphyry system with potential ore grade mineralisation over wide intervals. Best drill intercepts include 494 metres (m) at 0.22% Cu, 163 ppm Mo and 1.09 ppm Ag and 128 m at 0.21% Cu, 71 ppm Mo and 0.9 ppm Ag. Best molybdenum intercepts included 5 m at 580 ppm and 25 m at 315 ppm Mo.

Aeon also has been drilling at the Kildare Project, 13 km south of the Greater Whitewash Project, which is owned by joint venture company SLW Queensland Pty Ltd (Aeon 35%, and Hong Kong based SLW Minerals 65%). Best drill results to date include 6 m at 4264 ppm Mo and 40 m at 475 ppm Mo.

In February 2011, Zamia Metals Limited reported an upgraded JORC Code compliant Inferred Resource of 173 Mt grading 0.43% Mo at a cut-off grade of 200 ppm Mo, for 163 million pounds of contained Mo, for its Anthony molybdenum deposit, approximately 60 km north-northwest of Clermont, Qld. The deposit is a porphyry molybdenum system associated with the Dead Horse Bore intrusive complex in which the molybdenite occurs in stockwork quartz veins and breccia zones within intrusive rocks as well as in surrounding schists of the Anakie Inlier. The deposit is oxidised to a depth of 60 to 80 metres. In June 2011 and March 2012, the Inferred Resources were upgraded to include the Oxide Resource and the Transitional Resource respectively, with total resources of 260 Mt at 400 ppm Mo, at a cut-off grade of 200 ppm Mo, for 230 million pounds of contained Mo. Zamia is evaluating project economics and joint venture options for the Anthony deposit.

Intermin Resources Limited's (Intermin) wholly owned Julia Creek Vanadium-Molybdenum project has a total resource of 5308 Mt grading 0.375% vanadium oxide (V2O5) and 312 g/t molybdenum trioxide (MoO3), within the St Elmo, Alisona and Lilyvale deposits, spread between Julia Creek and Richmond, in northwest Qld. Just over 80% or 4332 Mt of the total resource comprises Indicated Resources with contained molybdenum of slightly more than 900 kt. The resource includes Measured Resources of 204 Mt at 0.4% V2O5 and 300 g/t MoO3. Intermin's tenements are located within the Cretaceous Toolebuc Formation of the Eromanga Basin, where vanadium and molybdenum, as well as nickel and copper, occur within weathered and fresh oil shale horizons. The company is undertaking laboratory testing and feasibility work into mining the Lilyvale resource, which includes higher grade Indicated Resources of 87.7 Mt at 0.55% V2O5 and 384 g/t MoO3. Intermin also is in negotiations with potential investors. The company has indicated that the moratorium on oil shale mining introduced by the previous Queensland government has complicated this task.

In 2011, Metallic Minerals Limited completed the sale of its wholly owned subsidiary, Wolfram Camp Mining Pty Ltd, to the German mining company Deutsche Rohstoff AG (DRAG) to give DRAG an 85% stake in the Wolfram Camp tungsten-molybdenum project, 90 km west of Cairns in Qld. In November 2011, DRAG announced it had acquired full ownership of Tropical Metals Pty Ltd which had held the remaining 15% of the Wolfram Camp Mine project, as well as all of the Bamford Hill tungsten-molybdenum deposit 25 km south of Wolfram Camp. This gave DRAG full control over both deposits. The most up-to-date resource estimate for Wolfram Camp was released by Planet Metals Limited in May 2010 and reported 1.42 Mt grading 0.6% tungsten trioxide (WO3) and 0.12% Mo, comprising 0.78 Mt at 0.56% WO3 and 0.13% Mo in Indicated Resources and 0.64 Mt at 0.65% WO3 and 0.11% Mo in Inferred Resources. DRAG delivered its first WO3 concentrate from Wolfram Camp in February 2012 and in June 2012 daily production was reported to be about 1.5 tonnes of concentrates a day. DRAG has forecast that the Wolfram Camp mine will produce approximately 7000 tonnes of WO3 concentrates and 800 tonnes of Mo concentrates during the next four years. 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.

Thor Mining PLC (Thor) has reported in January 2012 that its Molyhil tungsten-molybdenum project 250 km northeast of Alice Springs in the NT had 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 include Probable Reserves in open cut at April 2012 of 1.64 Mt at 0.42% WO3 and 0.13% MoS2. Potential development of the project was hampered by the global financial crisis and a decline in international metal prices, resulting 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, committing it to taking all 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 definitive feasibility study of the deposit, with a mine life of four years based on current reserves.

Moly Mines Limited's (Moly Mines) Spinifex Ridge Molybdenum-Copper Project, containing the Spinifex Ridge deposit is located in the Pilbara region about 50 km northeast of Marble Bar. The Spinifex Ridge deposit has a Measured and Indicated Resource of 206.8 million tonnes (Mt) at 0.06% Mo, 0.1% Cu and 1.5 g/t Ag and 445.5 Mt at 0.04% Mo, 0.07% Cu and 1.1 g/t Ag, respectively (2008 figures, reissued in 2012). The total resource of 652 Mt contains 294.5 kt Mo, 5.2 kt Cu and 26.4 million ounces Ag. Mineralisation at Spinifex Ridge occurs as vein-hosted molybdenite and chalcopyrite associated with an Archean granodiorite which has intruded mafic and felsic volcanic rocks. The Spinifex Ridge Molybdenum-Copper Project has all the necessary permits and is ready for immediate development. The deposit underwent a feasibility study and, prior to the global financial crisis, was scheduled to become Australia's only molybdenum producer. As indicated by Moly Mines, the deposit is sub-economic at current metal prices and is on hold until markets improve. Prior to the downgrade by Moly Mines, which resulted in reclassification of 220 kt of reserves to Paramarginal, the deposit contained more than 75% of Australia's EDR of molybdenum, but less than 1% of Australia's EDR of copper.

Peel Exploration Ltd (Peel) released a resource estimate in April 2008 of 1.29 Mt at 0.61% WO3 and 0.05% Mo, for the Attunga deposit 20 km north of Tamworth in New South Wales (NSW). Mineralisation at the deposit occurs within skarns developed at the contact of a lime-rich sequence with the Inlet Monzonite. In 2010-11, Peel undertook a study to investigate development options, which revealed conditions were favourable for a low capital expenditure operation. There was no field activity in 2011-12. In April 2012, Peel indicated it had begun a review of the Attunga tungsten deposit. The company has indicated it is seeking potential joint venture/off-take partners.

In March 2012, Straits Resources Limited (Straits) announced a significant resource upgrade for its Temora copper-gold project southeast of West Wyalong in southern NSW. Total resources are 279 Mt at 0.5% Cu, 0.2 g/t Au, and 30 g/t Mo, of which 26 Mt at 0.3% Cu, 0.5 g/t Au and 30 g/t Mo are Indicated Resources with the remainder being Inferred Resources. The resource occurs within the Yiddah, Mandamah, Culingerai, Estoril and Dam prospects.

In 2011, Zodiac Resources Pty Ltd which is 58.7% owned by Goodrich Resources, entered a farm-in agreement with Augur Resources (Augur), which allowed Zodiac to acquire a 75% interest in Augur's Yeoval Project, about 85 km north of Orange in NSW. Augur previously released an Inferred JORC Code resource estimate for the Yeoval Porphyry deposit of 12.9 Mt at 0.38% Cu, 0.14 g/t Au, 120.1 g/t Mo, and 2.2 g/t Ag. Zodiac completed an Induced Polarisation survey around the Yeoval deposit and its environs in 2012 which suggested that the known mineralisation was part of a larger mineralised system.

Dart Mining NL (Dart) released upgraded figures in September 2012 for its Unicorn Project 20 km south of Corryong in northeast Victoria which show the deposit has total resource of 203 Mt at 355 ppm Mo, 480 ppm Cu and 2.97 ppm Ag. These include Measured Resources of 102 Mt at 367 ppm Mo, 599 ppm Cu and 3.58 ppm Ag for a contained 38 kt Mo, and Indicated Resources of 35 Mt at 362 ppm Mo, 414 ppm Cu and 2.75 ppm Ag for a contained 13 kt Mo. Molybdenite (MoS2) mineralisation at Unicorn is associated with rhyolitic intrusives and occurs within stockwork veins in the rhyolites, surrounding metasediments and breccia zones. It is disseminated also throughout the rhyolites. Dart completed a favourable scoping study into the deposit in October 2012, which suggested an initial open pit mine life of 14 years with annual production of 10 million tonnes per annum. Metallurgical testing demonstrated molybdenum recoveries of more than 90%. Dart has indicated it plans to initiate a prefeasibility study as well as look at the potential of underground mining.

Havilah Resources NL (Havilah) reported a combined JORC Code compliant Indicated and Inferred Resource of 11.3 Mt grading 0.89% Cu, 0.64 g/t Au and 500 ppm Mo for 5.68 kt of contained Mo for its wholly owned North Portia deposit 30 km north of its Kalkaroo deposit in South Australia. The vein and breccia style of mineralisation at the North Portia deposit is hosted in a 150-metre sequence of carbonate-rich siltstones and shales. Resources occur in both supergene and sulphide mineralisation. Havilah also identified a standalone supergene molybdenum resource with Indicated Resources of 7.7 Mt at 340 ppm Mo for a contained 2.6 kt of Mo. Havilah indicate that a mining lease has been granted for North Portia and that metallurgy and mining studies are in progress, particularly with regards to the copper-gold-molybdenum in the oxidised ore.

Endnotes

22 Revised downward from 607kt figure reported in 2011 AIMR Report.