EL 1167 Boxhole Bore, Northern Territory Annual report for year ended 05-03-1977.

Abstract

Investigations in the area covered by the EL have concentrated in the Turkey Creek - Boxhole Bore vicinity where lead sulphides were located in silicified dolomites in 1959. A number of shallow pits were sunk on outcropping mineralization over a 3 km strike length by the finder, Mr. W.H. King. Enterprise Exploration drilled a total of 8 core holes aggregating 439 Ii in 1960 to test the westerly (down dip) extension of mineralization. Concurrently the area was mapped by the BMR both regionally and in the vicinity of the workings. Results of the drilling were not encouraging. In 1971 Central Pacific Minerals undertook an induced polarization programme followed by percussion drilling of 9 holes aggregating 337 metres close to outcropping mineralization. Assay results suggested that no further work was warranted. Australian Anglo American conducted a gravity survey and undertook some detailed geological mapping during 1974. Follow up work was not recommended. In summary, previous workers recognised the stratabound nature of the mineralization and tried various techniques to locate extensions down dip. Results were not considered sufficiently encouraging for further work. The principal object of the exploration programme to date has been to locate lead and zinc mineralization in Cambrian carbonate rocks ie mineralization of the Mississippi Valley type. To this end the following continuing work programmes have been initiated. (i) Inspection and analysis of cores and cuttings from available previous drilling to locate anomalous areas and to assist in interpretation of the stratigraphic sequence. (ii) Interpretation en a regional basis of available geophysical data (gravity and aeromagnetics) in an aattempt to define basement topography and subsequent fault structures. (iii) Regional and photo-geological interpretation at 1:80,000 scale to aid surface mapping. (iv) Reconnaissance prospecting using geochemical spot tests and soil sampling to locate surface indications of mineralization for more detailed work. Cv) Reconnaissance geological traversing and mapping to locate favourable lithological units and structures. (vi) Drilling to test for mineralization and to aid stratigraphic interpretation. Unfortunately cores from Enterprise Exploration drilling in 1960 were not available for inspection. Analysis results of samples taken from 3 Central Pacific Minerals percussion holes (W04, WDS and WD6) are included. Mapping was carried out at a scale of l:2,000 over the mineralized area. A plan incorporating this work and previous geological mapping is given along with soil sample traverse locations. Analysis results are plotted. Four diamond drill holes located on selected points of a 1600 m square grid failed to intersect sulphide mineralization. Aggregate depth was 786.65 metres. Interpretation of the regional geophysical data did not yield specific targets within the Exploration Licence. No surface mineralization was located away from the Boxhole Bore region during a reconnaissance prospecting programme.