The Scheelite Prospects of the Jervois Range, Bonya Creek and Molyhill areas

Abstract

The scheelite prospects of the Jervois/Bonya Creek/Molyhill area, Northern Territory are found in calc-silicate rocks of various compositions, charactertically vesuvianite-rich at Jervois, garnet-amphibole-rich at Bonya Creek and magnetic-rich at Molyhill. Scheelite occurs such as quartz or calcite. The mineralized calc-silicates at Jervios and Bonya occur in a medasediment sequence intruded by granite. The Molyhill calc-silikcate is a proof pendant. Most mineralisation occurs close to granite or granite pegmatite. The most important of the scheelite prospects in the region are held by Petrocarb Exploration NL under leases, claims or applications, or under options from the Johannsen family. Those prospects examined in detail are the Crystallization Plant, Green Parrot and Bellbird Scheelite prospects at Jervois, the white Violet, Samarkand and Jericho prospects at Bonya Creek and the Moylhill open cut. Each of these prospects has been sampled or drilled previously. Os these, the Bellbird Scheelite, White Voilet and Molyhill open cut prospects are the largest, having surface potentials of about 5000, 3330, and 7000 tonnes/ vertical metre respectively. Despite the relatively large tonnage potential grade is difficult to estimate by conventional sampling. Drilling results and visual estimation at Bellbird Scheelite and White Violet Prospects suggests grades of 0.3percent and 0.4percent WO3 respectively, with small high grade patches. The Molyhill prospect which is currently being mined at a small scale has a recovered grade of 0.5percent WO3. Without estimates of head grade to the mill the deposit may have been assumed to have a grade of 0.5percent, although, available assays from drilling suggest 0.3percent may be more realistic overall. Of the smaller deposits, the Jericho prospect at Bonya Creek has probably the best potential with 600 tonnes per vertical metre at a grade of about 1percent WO3 estimated visually and from drilling results. Further drilling and bulk sampling of all of these prospects should be carried out before a firm estimation of tonnage and grade can be made, since most potential lies at depth.