Annual report on EL 2087 for year ending 7-9-88.

Abstract

Exploration Licence 2087, in the Maranboy area of the Northern Territory, is subject to an agreement between the title holder Ken Day Pty. Ltd. and Denehurst Limited as operators. The EL is located within the southern part of the Pine Creek Geosyncline and comprises early Proterozoic greywackes, siltstones, argillitesand pyroclastics of the Tollis Formation which are intruded by the Maranboy Porphyry and the Yeuralba Granite. These rocks are overlain by Cambrian sandstones and by Cretaceous sediments. Structurally,the Maranboy area is dominated by the Maranboy Anticline, with major faults trending ENE which appear to post-date the mine ralisation. Elliott Exploration Co. Pty. Ltd. were commissioned to undertake a field assessment of the area. This included geological reconnaissance aimed at locating outcropping mineralisation, rock chip sampling and stream sediment sampling. It is concluded that: 1) EL 2087 contains areas of significant tin mineralisation, evidenced by previous working and anomalous areas defined by geochemical sampling. 2) A number of arsenic/base metals anomalies are present, and 3) Although a series of brecciated fault zones with associated mesothermal/epithermal multi-phase quartz-fill occur throughout the area, detailed sampling revealed no gold or base metals content. Drainage geochemistry yielded no trace of gold in the area. It is recommended that: a)Detailed sampling, petrographic and mineragraphic work be carried out on old tin workings to clarify the processes of tin mineralisation operating within the field. b) Detailed geological mapping and geochemical sampling of anomalous tin areas identified by this work programme should be undertaken. c) Detailed geological and geochemical follow-up should be carried out on areas of anomalous arsenic/base metals identified by the current programme. Rock chip samples were selected to locate tin mineralisation rather than assess potential grade of mineralised outcrops. Samples returning tin values in the per cent range therefore would warrant some follow up work. Statistical analysis of the assay results generally indicates that two populations are present, and it is postulated that this feature is related to the subjective manner in which some samples were selected as well as the sampling of two styles of potential mineralisation. The latter effect is highlighted by the occurrence of non-coincident tin/base metal/arsenic anomalies. Stream sediment and pan concentrate samples assays can be treated more objectively, however statistical analysis is affected by the fact that the population of samples is not large and the population does not consistently sample all orders of drainage, due to: the nature of streams in the area and sample availability was generally poor. In addition to these factors, it is clear that some samples returned high tin values due to the presence of old workings in or near the drainage system. No detectable values for gold have been returned, either in rock chip, sediment or pan concentrate samples. This element will not be discussed any further.