Molybdenum

Content maintained by Roy Towner and Leesa Carson

• Molybdenum
• Resources
• Exploration
• Production
• World Ranking
• Industry Developments

Molybdenum (Mo) is used in steels and superalloys to enhance strength, toughness and corrosion resistance. The main commercial source of molybdenum is molybdenite (MoS₂) but it is found also in minerals such as wulfenite (PbMoO₄) and powellite (CaMoO₄). Molybdenum is mined as a principal ore and is recovered as a by-product or co-product of copper and tungsten mining.

Australia' s Economic Demonstrated Resources (EDR) of molybdenum rose from 198 kilotonne (kt) in 2007 to 224.6 kt in 2008. All the increase in economic resource occurred at Spinifex Ridge in Western Australia (WA). Western Australia is the largest holder of molybdenum resources with about 98% of EDR followed by the Northern Territory (NT) with 1.4% EDR. All EDR is accessible for mining. JORC Code Reserves account for 99% of EDR.

Subeconomic Demonstrated Resources account for about 62% of total Demonstrated Resources. Queensland (Qld) accounts for 75% of subeconomic resources followed by WA with 23% and South Australia (SA) with 2%. In 2008, the Paramarginal Resources increased by about 9% to 101 kt, while the submarginal resources decreased from 261.7 to 259.7 kt because of resource assessment. Inferred Resources increased by 35% to 664 kt in 2008. WA and Qld account for 60% and 39% of Inferred Resources respectively.

The rise in molybdenum price has led to increased molybdenum exploration, which has resulted in resource upgrades for several deposits. Data relating to exploration for molybdenum are not available nationally.

There was no molybdenum production in Australia in 2008.

The distribution of molybdenum resources and production is concentrated in a few countries, with China, the United States (USA), Chile and Canada holding about 88% of the resources. In 2008, world economic resources are estimated to be about 8600 kt based on the United States Geological Survey (USGS) data.

USGS estimates that world production in 2008 amounted to 212 kt of molybdenum which compared with 205 kt in 2007. The USA, China and Chile accounted for about 78% of global outputs in 2008 with USA producing 61.4 kt followed by China with 59.8 kt and Chile with 45 kt.

The world molybdenum price 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, but declined sharply from late October 2008 to US$8/lb where it continued through the first quarter 2009.

For almost 20 years the market has been stagnant, but has been transformed as a result of limited supplies and continued strong demand. China's high level of steel production and consumption has led to strong internal demand for molybdenum. This consumption, together with export quotas, continued to reduce China' s molybdenum exports in 2007 and through 2008, thereby supporting the high prices.

In June 2008, Queensland Ores Ltd announced the processing of the first tonne of molybdenum concentrate at its Wolfram Camp tungsten-molybdenum project 90 kilometres (km) west of Cairns in Qld. However, the company suspended operations on 18th November 2008, because of a number of mining and metallurgical issues which impacted on the performance of the treatment plant and the production of the concentrates. The two principal problems were the inability to deliver targeted grade material to the run-of-mine stockpiles, and the inability of the treatment plant to recover an acceptable quality of concentrates from the ore feed. The falling price of molybdenum in late 2008 compounded these issues. In June 2009, Metallic Minerals Ltd completed a takeover bid of Queensland Ore Ltd.

In 2008, Moly Mines Ltd signed a 10 year off-take agreement with ThyssenKrupp Metallurgie GmbH for 100% of its molybdenum product from the Spinifex Ridge project in the Pilbara region of WA. The molybdenum concentrate is toll processed to oxide and ferro-molybdenum under an agreement with Molymet at its plant in Santiago, Chile. Moly Mines is reviewing alternative development scenarios for the Spinifex Ridge project, reflecting the recent downturn in world molybdenum prices and the ongoing uncertainty in the international financial and credit markets. Scoping study activities have commenced for the development of an 8-10 million tonnes per annum (Mtpa) operation and processing plant. The project has a combined proven and probable ore reserves of 451 million tonnes (Mt) grading 0.05% Mo and 0.08% Cu.

Thor Mining PLC reported total Proven and Probable Reserves of 2.21 Mt grading 0.47% tungsten oxide (WO₃) and 0.21% molybdenum disulphide (MoS₂) for its Molyhil tungsten-molybdenum project, 250 km north east of Alice Spring in the NT. The company's proposed mine management plan for an open cut operation has been approved by the NT Department of Primary Industry, Fisheries and Mines, subject to placement of a bond for rehabilitation of the proposed mine site.

In 2008, Glengarry Resources Ltd sold its Maitland Cu-Mo deposit west of Townsville in Qld to Kagara Resources. The deposit has a combined Indicated and Inferred Resource of 1.5 Mt grading 1.5% Cu including 115 000 tonnes at 0.17% Mo.

In late 2008 Ivanhoe Australia discovered high-grade molybdenum and rhenium sulphide mineralisation at the Merlin deposit. Molybdenite mineralisation occurs in an east-dipping shear and breccia zone with extremely high-grade portions occurring as a molybdenite-supported breccia. The mineralised intervals are defined in a wedge-shaped body which tapers up-dip and bifurcates into upper and lower zones. The mineralised zone starts at a depth of 100 metres (m) and extends down-dip for more than 400 m, with an average width of approximately 25 m. The currently identified strike length is 900 m. The Merlin deposit, near Cloncurry in northwest Qld, has an Identified Resource of 13 Mt grading 0.8% Mo, and 14 grams per tonne (g/t) rhenium (Re), 0.2% Cu and 4.8 g/t Ag.