1929 Deposit of potassium nitrate ML 516, near Mount Sonder, Central Australia

Abstract

Early in 1927 beneath a flat capping manganiferous ironstone, a deposit of ochre coloured sandstone containing a considerable percentage of nitrate of potash was accidentally discovered by an indigenous boy about 120 miles W. from Alice Springs. He had entered a cave in the sandstone which had been formed by weathering under the edge of the ironstone and lighting a fire on the floor was frightened out by a burst of violent flame due to the ignition of crystals which had effloresced out of the exposed walls and floor. He mentioned his adventure to someone some months later with the result that Messrs Wolfe and J.O'Neil pegged out and registered a Mineral Lease No 516 with the Warden at Alice Springs on 23rd September, 1927. During the four months last summer that the writer spent in Central Australia inspection and sampling mining properties for a group of Melbourne capitalists he was told of this show by Mr. E. Alchurch, the local Post and Telegraph master. Being much interested he got all available particulars and went out and inspected the claim on 9th February, 1929. As the site of the claim is rather far out in poor country about which little is known and very few people have actually seen it the following particulars should be interesting. The Mineral Lease as pegged comprises 40 acres taking in the above outcrop and another similar of large size approximately as shown on the sketch plan herewith. There is another still larger and of higher elevation above the plain, about half a mile away, which has not been taken up. The lease is described in the Warden's office as being nine 9 miles S.W. from Mt. Sonder, but it has not yet been accurately located or surveyed and appears to the writer to be more like five 5 miles W.S.W from that mountain and six (6) miles due South from Mt. Razorback and is eighteen (18) miles by track West from the gorge which the Fink River has forced through the main Macdonnell Range on its way South towards Lake Eyre and roughly some 50 miles N.W. from the Hermannsburg mission station. The sketch plan shows the size and positions of the two flattened iron-stone outcrops which stand up about 35 feet and 50 feet above the surrounding plain, The Northern and smaller cap has a superficial area of about 50,000 sq feet while the larger one to the South would be about half as large again and is flanked on the southern side by limestone containing fossils of obviously marine origin. At the S.E. corner of the smaller outcrop is a cave about 20 x 12 feet area x 5 feet deep, immediately below the ironstone cap which at this point is 4 feet or 5 feet thick. The walls and floor of this cave are an ochre-coloured soft sandy rock containing small translucent crystals with larger ones which have effloresced on the outside. Tests have been made of samples taken by the writer from this cave by W. Dods of 277 Franklin Street, Melbourne. See hard copy company report for results. See CR1940-0002 for further details.