The period 7th to 28th January, 1951 was spent at Selwyn by the writer: approximately one week was spent in preparing a semi-regional map at a scale of 1 inch to 400 feet; one week was given to mapping a smaller area at a scale of 1 inch to 40 feet. Level plans have been constructed showing what are considered to be the broad outlines of ore arrangement and structure and a number of sections have been constructed. Nineteen plans and sections illustrate this report. Twelve typical ore and rock specimens were studied in thin section and the information obtained has been incorporated in this report. An account of the regional geology of the prospect and the geology of the ore deposits is given in this report.

This report comprises notes on the geology, ores reserves, and exploration of the Maude and Yellow Girl Gold Mining Company.

This report describes a geophysical survey made in May 1952 and August 1953 at the Silver Valley mine workings, near Inverell, N.S.W. From the workings there is evidence of mineralisation along a well-defined fissure and one ore shoot has already been partly developed. The survey was made in an attempt to locate other ore shoots of sufficient size to warrant mining operations. Self-potential, magnetic and electromagnetic methods were used in the survey. The self-potential method showed a well-defined anomaly on the eastern extension of the fissure, indicating that a small body of sulphides may exist there with its centre about 300 feet east of the known ore shoot. The magnetic and electromagnetic results showed no pronounced anomalies which could be correlated with any defined ore shoot. Recommendations are made as to how the self-potential anomaly could best be tested. These comprise sinking a shaft at the centre of the anomaly, extending an existing adit, or driving a new adit from a point nearer the anomaly.

A geological report on the Alexander, Halley's Comet, and Manolis' Workings mines. The production, grade, geology, mineralisation, ore reserves, and prospecting of the mines are discussed. Accompanying geological plans are included.

A request was made for an estimation of the ore reserves indicated to date in the King Island Scheelite Mine, and for a drilling campaign to be drawn up to prove a total of fifteen years supply of ore at an annual rate of consumption of 200,000 tons. These two matters are dealt with in this report.

The Kangaroo Caves zinc-copper deposit in the Archaean Panorama District in the northern Pilbara Craton, Western Australia contains an Indicated and Inferred Mineral Resource of 6.3 million tonnes at 3.3% zinc and 0.5% copper. The Kangaroo Caves area is characterised by predominantly tholeiitic volcanic rocks of the Kangaroo Caves Formation, which is overlain by turbiditic sedimentary and volcanic rocks of the Soanesville Group. Zinc-copper mineralisation is hosted mainly by the regionally extensive Marker Chert, the uppermost unit of the Kangaroo Caves Formation, and structurally controlled by D1 synvolcanic faults. The upper area of the deposit is characterised by quartz-sphalerite ± pyrite ± baryte ± chalcopyrite, whereas the lower area contains mainly chlorite-pyrite-quartz-carbonate-sericite ± chalcopyrite ± sphalerite. Laser ablation inductively coupled plasma mass spectrometry analyses show that cobalt-nickel ratios in pyrite are significantly greater in the upper, zinc-rich area (median copper/nickel = 0.4) of the deposit than the lower, zinc-poor area (median copper/nickel = 5). Structural analysis of the Kangaroo Caves area combined with Leapfrog modelling of ore and trace element distribution shows that the deposit is predominantly an elongate sheet of zinc mineralisation (-1%), which plunges ~30° to the northeast and is approximately 1000 metres in length. The morphology of the Kangaroo Caves deposit was retained from its original formation, despite rotation during the D2 event. Variations in hydrothermal alteration assemblages, including the copper and nickel contents of pyrite within the deposit and underlying dacite, are interpreted to be the result of variations in the influx and mixing of seawater with upwelling volcanogenic fluids during zinc-copper mineralization. At the Kangaroo Caves area the cobalt-nickel ratio of pyrite can be used as an exploration vector towards high-grade zinc-copper mineralization.

A geological survey of the mount Bischoff Mine area was commenced in January, 1944, with the objects of delimiting the known ore shoots, determining the field relationships of those and so arriving at an understanding of ore occurrence which could be applied to the location of possible new shoots. By April the open cut area had been surveyed accurately and in detail, a general geological reconnaissance made and detailed geological mapping carried out of half of the open cut and a considerable part of the area outside the open cut. This report comprises a discussion of existing and suspected ore reserves. The report includes an assay plan and a diagram of assay sections of the Greisen orebody.

This report presents the results of a geological investigation of the Crusader copper deposit, Dobbyn, Queensland. The purpose of the survey was to investigate the geological setting of the Crusader Mine and thereby to determine the factors controlling the deposition of ore, and the possibility of producing ore from the deposit. An area of about six square miles was mapped using enlarged aerial photographs, and a plane table survey was made of the miner area, using a telescopic alidade.

The Cobar mining field was examined between August, 1946 and June, 1947. Attention was concentrated on the operating mines, viz. New Occidental, New Cobar and Chesney. New Occidental Gold Mines, N.L. owns all three deposits and had requested assistance from the Commonwealth Government to search for new orebodies on their leases. It had previously been recognised that each of these orebodies lay close to a sharp contact between fine-grained and coarse-grained sediments. Of particular interest are the portions of the contact which have been subjected to minor folding, because, immediately to the south of these folds, fracturing favourable for ore localisation has developed. The geological examination was carried out in conjunction with the Geological Survey, Mines Department, New South Wales. Surface and detailed underground mapping were carried out. A preliminary magnetic survey of part of the field was carried out by the Geophysical Section during the first half of 1947. A special study of the New Cobar Mine and the plans of that deposit were made by Dallwitz, Fleischman and Ivanac. This report provides a comprehensive overview of the situation, topography, history, structural geology and general geology of the area. Detailed descriptions are given of the history, workings, orebodies, and structure of each individual deposit. Various accompanying plans of the mines and the Cobar mineral field are included.

The mine manager at Mount Bischoff Tin Mine, Mr. Eddy, proposes to mine the Greisen Orebody by means of a system of gloryholes, in combination with stoping. It was requested that a scheme of development work necessary for opening up the orebodies preparatory to mining should be decided on and set out on paper. This report is concerned with the proposals for development and testing work which would determine whether the larger gloryhole would be justified or whether a smaller gloryhole on the hanging wall ore and stoping on footwall ore would be a more profitable method.