Report on evaluation of Marktree vermiculite deposit, Mud Tank carbonatite complex NT for the period 1 January 1988 to 30 November 1988

Abstract

This report covers work carried out in the period 6 to 18 months from commencement of AS81 and is the second report on the Mud Tank Carbonatite Complex. Current exploration has included regional drainage geochemistry, photo interpretation, Landsat imagery interpretation including detailed Thematic Mapper imagery studies, acquisition of new colour aerial photography and excavation, mapping and sampling of about 2.5km of costeans. A calweld drilling program was completed in conjunction with a significant bulk sampling program. All samples were processed through a crushing and screening plant and various product retained for further work. Bulk samples were tested in a commercial exfoliation furnace to determine bulk density characteristics of 1 to 2mm material. Some results were within acceptable limits, however, variable furnace performance has been indicated by the results. Resource potential calculations, based on a number of assumptions as to geological continuity, ultimate ability to beneficiate the vermiculite and weathering depth, indicate geological potential for 4 to 7 million tonnes and vermiculite that may have ore potential in the Zircon Hill area. Early dioritic intrusive phases have been identified in the carbonatite complex. These have been largely metasomatised to mica rich rocks. Both metasomatic and magmatic mica dominated units are thought to be present and a range of variably differentiated generally calcite dominated intrusive's together with alkali pegmatite's form the youngest phases of the carbonatite complex. Evidence of only minor fenitization of wall rocks has been and consists dominantly of feldspathisation and minor restricted green amphibole development. The future program will consist of additional consteaning at various locations on Zircon Hill and close spaced drilling to better identify resources and additional costeaning on other parts of the carbonatite complex to explore lenses with ore potential. Drainage geochemistry will be completed, together with photo feature evaluation. Laboratory test procedures are to be developed to provide reliable small scale test procedures and an extensive program of asbestos testing undertaken. Metallurgical testing will include crushing tests, beneficiation tests in air classifiers and concentrate exfoliation in various types of exfoliation. Environmental studies will be commenced to support any lease application that may be made by SCSC. Exploration for supplies of process water may be undertaken pending resolution of metallurgical problems.