Molybdenum (Mo) is used as an alloying element for stainless steel and other metals. It enhances the resistance of metals to corrosion and their strength at high temperatures. Molybdenum is also used as a refractory metal in chemical applications, for example, for catalysts, lubricants, and pigments. For most uses of molybdenum there is no acceptable substitute.
Although molybdenite (MoS2) has been found widely in Victoria, production has been recorded from only five deposits. The most significant of these was the Everton deposit. Like tungsten, molybdenum deposits are found mainly at the margins of highly fractionated and oxidised I-type granitic intrusions or adjacent to metamorphic aureoles, where they form during late magmatic hydrothermal activity. The deposits are commonly irregular vein networks, joint fillings, or disseminated flakes in pegmatite or aplite dykes.
Molybdenite is a minor component of most of the copper deposits in eastern Victoria. It is associated with Early Devonian intrusions including the Wangarabell, Croajingalong, and Genoa Peak granites in the far east of the State; the Everton Granodiorite in the Tabberabbera Zone; and the Moliagul Granodiorite, Mount Korong Granite and Mafeking Granite in western Victoria. There are also minor molybdenite occurrences near Gong Gong, Pittong, Maldon, Dromana, Yea, Violet Town (all Late Devonian), and Mount Stavely.
Mineralisation at the Everton deposit is in the form of a distinctive concentric pipe-like body. Between 1917 and 1944 the Everton mine produced approximately 325 tonnes of molybdenum concentrate. Mount Moliagul has been the subject of sporadic exploration and mining, but there has been little production from this area.
At the Mount Unicorn base metal prospect in eastern Victoria, geochemical sampling has identified a high-grade molybdenum anomaly over a 20 hectare surface area. Molybdenum at concentrations of up to 997 ppm was found in soil and rock samples. Two nearby molybdenum prospects in porphyry targets at Mount Morgan and North Mammoth are also being assessed.
There have also been minor amounts of molybdenum production from Mount Douglas near Wedderburn, Wangarabell in East Gippsland, and the Womobi wolfram mine near Thologolong where molybdenum was produced as a by-product of tungsten mining.
- Minerals of Victoria - Geological Survey of Victoria Report 92
- Victoria's Minerals, Petroleum and Extractive Industries - Statistical Review
- Geology of Victoria - Geological Society of Australia