This geophysical survey was undertaken as part of a campaign by the N.S.W. Mines Department and the Commonwealth Bureau of Mineral Resources to explore the ore possibilities of the Cobar Mining Field. Tests, made in January 1947, on specimens of ore from the operating mines showed that some of the ore from the New Cobar and Chesney Mines exhibited appreciable magnetisation due to its pyrrhotite and possibly magnetite content. The survey was commenced in March, 1947 using the magnetic method only as a first method of attack. Watts Vertical Force Variometers Nos. 15887 and 16128 were used, the field work being carried out by the writers. The geology of the area, object of the survey, results, and recommendations for future drilling are discussed in this report. Two accompanying plans are included.

The geology and ore reserves of the dolomite deposit near Wall's Siding are discussed in this report. The report should be read in conjunction with the report on "Limestone and Dolomite Deposits at Cow Flat and Wall's Siding, New South Wales" (Record 1947/090).

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.

The Blue Spec Mine, Nullagine, was visited from 20th to 24th September, 1947. An inspection was made of the mine. No. 3 level (depth 450 feet) was mapped and the antimony-gold occurrences on lease 196, and on the property known as "Blacks", were also briefly inspected. The present position regarding water supply was investigated and recommendations made. The ore reserves, workings, economic considerations, and water supply are discussed in this report.

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 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.

Ore reserves in the Geiger-Main and Whip Lodes at Radium Hill have been calculated from up-to-date plans and assay data provided by the South Australian Mines Department and results obtained agree closely with estimates made by the Mines Department. Tonnage of ore (not including dilution) to 600 feet depth on Geiger-Main and Whip Lodes and to 400 feet in Main Lode South block is estimated at 337,500 tons containing 938 tons U3O8, corresponding to an approximate average of 160 tons U3O8 per 100 feet of vertical depth. The data used, method of calculation, and results, are discussed at length in this report.

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

During the past three to five years small amounts of oxidized copper ore have been reported from various localities in the James Ranges to the west of Alice Springs. During a visit to Alice Springs in July of this year information on these deposits was obtained from the Resident Geologists, A.D.M. Bell, and it is considered that potentially they may be of considerable importance and Bell has been instructed to investigate them further. The deposits are briefly discussed in the monthly report by Bell dated 3rd July, 1953. In this report he states that the rocks to the west of Alice Springs, where limestones are developed only on a comparatively small scale, are not likely to contain ore deposits to the extent of those to the east of Alice Springs where extensive limestone deposits occur. This concept is discussed below. [A supplementary note is enclosed which describes an inspection of the area which was conducted in September 1953].