1939 Report on a visit to the Excelsior Lease, White Range.

Abstract

In compiling the following report on the recent inspection of White Range, made in company with your Engineer, Mr. Chas. TheBon, I have assumed that the report is supplementary to Mr, TheBon's report, and have consequently omitted all details of the trip itself, and other matters apart from technical considerations. The White Range, about 6 miles from Arltunga, and 70 from railhead at Alice Springs, is a massive ridge bearing approximately S 30E from a fairly abrupt escarpment on the N.W end and curving round towards the East, where it falls away easily to the general level of the surrounding country. It is composed of bedded quartzite, Neither in the immediate neighbourhood, nor anywhere in the country which we traversed from Alice Springs by car, were any occurrences of plutonic rocks visible. The beds of Quartzite are lying at low angle - 150 to 200 - dipping to the N.E, and are crossed at intervals by stringers and veins of hard white quartz, with a very regular strike of 240 (approx. NE - SW) dipping at 50 to the S.E. The veins of quartz vary in width from a few inches to 50 feet or more, and in the centre of the larger quartz bodies large vugs or lenses of honeycomb quartz have been formed, which have been filled (in my opinion) with a Secondary enrichment of suriferous pyrites, weathering near the surface to a gossany ironstone. These lenses of mixed quartz and ironstone constitute the ore-bodies which have been worked when the White Range was producing gold. Measurements were taken of one of the more regular of these excavations. It was 93 ft, long and 56 ft, deep lenticular in shape with a maximum thickness of 15 ft, and an average thickness of 5 ft. Probably about 1500 tons of ore were taken from this lens. The quartz walls of the excavations are heavily stained with iron, with an, occasional inclusion of iron pyrites. Samples were taken by cutting across the quartz formation from wall to wall of the excavations, and it is to be borne in mind that (assuming the correctness of the theory of a secondary deposit in the honeycomb quartz) such samples would naturally be richer than samples taken across the quartz formation further removed from the lenses, hence the probabilities of a working value in the main quartz bodies been greater, it would have been considered necessary to sample the veins at points free from the possibility of poisoning but the richer ore of the lenses. In view of the cost and difficulty of opening up these formations for sampling, and as a result of panning; samples taken, it was judged to be unnecessary.