Annual report EL 2710, 15 July 1982 to 14 July 1983

Abstract

In the 1982-83 licence-year drilling continued, although principally at Anomaly 4-5. Five holes, with a cumulative depth of 471.50m. were completed, of which 144.40m. was rotary percussion and 326.75m. NQ diamond drilling. The stratigraphy of the Bigrlyi Prospect is concerned with a portion of Lower Mt. Eclipse Sandstone, positionally near Basement although somewhat younger than similarly placed rocks of the eastern Ngalia Basin. Essentially, the rocks are a fairly monotonous sequence of crossbedded sandstones varying mainly in colour and the nature of the cement. The zone of interest has been mapped in terms of eight units, labelled A-H. The youngest, Unit A, is a general term for any rock above Unit B and is not a unit in the same sense as the others. Unit B is distinctive being red and grey and/ or green and is micaceou~ calcareous and fine grained. It contains potentially economic mineralization at Anomaly 8 and somewhat weaker mineralization at Anomaly 14-15 (and possibly elsewhere). Unit C is generally a medium grained grey unit and is host to the bulk of the mineralization at Bigrlyi. Unit D is lithologically similar to Unit C except that it is red and tends to be barren. Exceptions can be found at Anomaly 8 and most notably at Anomaly 4-5 where significant grades have been obtained during the course of this years work. The remaining units are red and to this point, nave been found to be barren. A brief reconnaissance radon-in-soil gas survey was carried out in the area east of Anomaly 15.