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.

Dyson's Find is situated 1000 yards east-north-east of White's workings. A radiometric anomaly was discovered here in 1950 by geophysicist D.F. Dyson while traversing the sedimentary rocks between Giant's Reef to the south and the edge of Rum Jungle to the north. No uranium minerals were visible on the surface but costeaning revealed four lines of strong secondary uranium mineralisation. In 1950 the area was mapped by H.J. Ward on a scale of 50 feet to one inch. A prospecting shaft (No. 1 Shaft) was sunk to a depth of 54 feet on one of the uraniferous lodes and some costeaning carried out. In 1951 further mapping on a scale of 20 feet to one inch was done by the writer. Diamond drilling was carried out and a new shaft (No. 2) was sunk to 84 feet. A plan showing the surface geology and working and a section along coordinate N170 accompanies this report. [Geology, structure, mineralization, workings, diamond drilling, ore reserves, and prospecting recommendations are discussed].

The geology, production history, ore grade, and ore reserves of the Northern Star Mine are discussed in this report. Four accompanying plans are included.

During the 1950 Field Season three radiometric anomalies were located by geophysical methods on a low hill situated between 1,300 and 2,000 feet east of White's Deposit. This area is known as White's Extended Prospect. In 1951 geological mapping on a scale of 40 feet to an inch was undertaken and this was followed by costeaning and diamond drilling. Owing to other commitments in the Rum Jungle area the explanatory programme and mapping in the White's Extended area has not been completed.

Fluid inclusion studies have been carried out on quartz veining from Jackson's Pit and Eva uranium mines and the Dianne and St Barb copper prospects in the Westmoreland region. Four types of inclusions have been observed. Type A, vapour-rich inclusions, contain 30 - 100 vol.% vapour with varying amounts of CO2 ± N2 ± CH4. Type B, liquid-rich inclusions, contain up to 30 vol.% vapour. Type C inclusions are liquid-only. Type D, three-phase (vapour + liquid + solid) liquid-rich inclusions, contain a small daughter crystal. Type A, vapour-rich inclusions and some Type B, liquid-rich inclusions homogenised over the range 171 to 385°C. Other Type B and Type D inclusions typically homogenised between 100 and 240°C with a mode around 120°C, while the presence of liquid-only inclusions suggests trapping at temperatures below 50°C. This may indicate three phases of fluid flow in the region with progressively cooling fluids. Eutectic melting temperatures as low as -79.8ºC in Type B and C inclusions suggest the presence of CaCl2 and other salts in the fluids. Final ice meeting temperatures for Type B and C inclusions fall into two groups. The first group has final melting temperatures below -10ºC while the second group shows final meeting above -10ºC and more typically close to 0ºC indicating the presence of low salinity fluids. This suggests mixing between saline basinal fluids and low salinity meteoric fluids that continued down to temperatures below 50°C.

The existence of wolfram in the deposit has been known since about 1915, and mining was carried out intermittently from that time until about 1938. It was not until June, 1951, when the deposit was visited by us, that the existence of scheelite in important quantity in the known ore was established. During this visit, also, a study of the structure of the deposit convinced us that, although only a little ore was exposed, considerable quantities of non-outcropping ore might be found. As magnetite is one of the gangue-minerals, a request was made for a magnetic survey. This survey was carried out by the Geophysical Section. Subsequent diamond drilling by Tungsten Consolidated Limited has shown that substantial bodies of scheelite and wolfram ore exist in the area under the structural conditions originally postulated; these conditions are outlined below. The geology of the deposits and the results of combined geological, geophysical, and diamond drilling investigations are discussed.

A review of mineral exploration activity in Australia for 2009. This extended edition includes coverage reported in the shorter edition.

Mapping carried out at Kuridala by C.J. Sullivan and R.S. Matheson during the period June 17th-27th has shown that the ore deposits occur in a major fault (and associated lesser shears). The existence of the fault system is considered to have been proved, and it has been traced, with some interruptions over a distance of three miles. It may extend for many miles beyond the present limits of mapping. The geological information given appears to rule out a number of chances of occurrence at shallow depth, formerly considered likely, and thus is somewhat discouraging. However, the work does indicate that repetition deposits are likely to be present and opens up intriguing possibilities.

The Treasure Mine, Hatches Creek, is believed to have been discovered in 1914 and has been one of the most consistent producers of wolfram to the present time. This report gives an account of the economic geology of the mine. The ore type, reefs and workings, ore localization, and ore reserves are described.

The Tallandoon Antimony mine, known locally as Dalgliesh and Murphy's, is 2 miles northwesterly from Tallandoon store on the main Omeo Highway and just within the northeast boundary of the Parish of Tallandoon, County of Bogong. This record comprises a description of the general geology and geological report on the antimony deposits.