Report on gold sampling on EL 12 Jabiluka 2, April-June 1975.

Abstract

Assays of metallurgical composite samples of Jabiluka Two uranium ore zones indicated the presence of gold in possible economic quantities. A programme for sampling gold was initiated in the first phase to involve assaying the individual uranium ore zones. Phase Two of the programme involved splitting and assaying Hanging Wall and non-ore Mine Sequence core, as well as assaying 1974/75 Wet Season Programme uranium intersections. Phase One of sampling programme is completed. Phase Two is still in progress. High gold values fall into two groups geographically and stratigraphically, five intersections being in the Mine Sequence ore zone and three intersections being in the Upper Graphite ore zone. Depth of intersection varies between 99 metres and 291 metres from surface.

Five of the intersections coincide with high, (>1% uranium) values, the other three contain low to medium grade uranium. Three include definite pitchblende veins, two contain uranium in injected chlorite. High grade uranium intersections do not necessarily contain gold. The most common host rocks for the gold appear to be chlorite schists and chlorite graphite schists. To date, results of the Hanging Wall sampling are not encouraging, the majority of values being below detection limit. Economic gold values occur in both the Upper Graphite and Mine Sequence ore zones of Jabiluka Two uranium orebody. Further drilling is required to establish continuity and limits of the gold bearing horizons and to indicate reserve potential.