A report on the Lake Cargellico magnesite deposit following a visit on 30th May, 1944.

At least as early as 1940, it was realised by the Department of the Interior that the reserves of suitable rock (shale or slate) in the pit adjacent to the Canberra Brickworks were limited. A decision was made to find a temporary site to provide sufficient material to supply the brickworks for two years. A site at Deakin, 1700 yards by road east from the existing brickworks was selected and was recommended by Dr. W.G. Woolnough in 1940 as suitable, subject to testing by costeans and pits. A survey of the area in the subdivision of Deakin, Canberra City Area, was then arranged and was made during March and April, 1944, the object being to determine if there were sufficient reserves of suitable material to supply the Canberra brickworks for a period of not less than two years. This report describes the results of this survey.

This sample of bryozoal marl from Montagu, Tasmania, was collected by Mr. F. Canavan. It contains a faunal assemblage typical of the Balcombian Stage of the Middle Miocene as found in Victoria and can be referred to Longford substage of the Balcombian.

Gibsonvale tin field is situated approximately three miles southeast of the village of Kikoira. This preliminary report was prepared following an examination of the tin field by the writer. Aspects of the general and economic geology of the field are discussed herein.

The area was visited in company with Mr. R.S. Matheson of the Geological Survey of Australia in December, 1942, when eleven pigmatite bodies bearing mica and beryl were examined. The report furnished after that visit (1943/2), gives details of access, topography, climate and vegetation which are not repeated here. In view of the urgent demand in Australia for "strategic" mica, i.e. mica of quality equivalent to Clear and Commercial-clear, it was recommended that one deposit at Yinnietharra should be opened and prospecting of others carried on simultaneously. As a result of these recommendations, the Deputy Controller of Mineral Production started mining operations on the selected dyke by open-cutting in June, 1943. Although it was stressed in the abovementioned report that poor exposure of the dyke, on which there were no workings, rendered any estimate of the probable yield of marketable mica speculative, the results actually obtained were far below expectations, and a heavy financial loss on the project was incurred. Consequently, while the question of abandoning the mine was under consideration, a detailed examination of the workings was carried out in June, 1944, again in the company of Mr. Matheson, and the results of this investigation, which was not wholly confined to geological aspects, are embodied in the present report.

A brief report on the occurrence of beryl on Yinnietharra Station, Western Australia was prepared following a visit to the locality in December 1948. That report referred to three deposits: 1) 0.25 to 0.5 mile N.25°W. from The Cairn; 2)0.25 mile S.60°E from the Mica King mine; 3) Rowe's mine, 2 miles southeast from Morrissey Hill. The report stated that 20 or 30 tons of detrital beryl in large pieces could be picked from the surface with ease. It was pointed out that by collecting small pieces and wider search the immediately available tonnage might be doubled. In June 1944, the first two of the above deposits were again visited, as was one on Bidgemia Station not seen on the previous occasion.

The Curragundi Bore is situated in Portion 15, Ph. Gingham, County Benarba, 12 miles east of Four Posts No. 2 Bore and 11 miles west of Midkin No. 3 Bore. It is about 40 miles southeast of Boronga No. 2 Bore reported upon 30/5/42. The samples examined for micro-fauna were taken from the depth of 50 feet down to 2107 feet 6 inches. The results of this micro-examination are recorded in this report.

These investigations were carried out at the request of the Secretary for the Navy. The following report is intended to confirm provisional information made available to naval personnel during and at the conclusion of the surveys. The Fremantle Degaussing Range is situated in Gage Roads near Fremantle Harbour. The position of the coils forming shallow and deep ranges is shown in Fig. 1. Deperming operations were carried out in Careening Cove, Garden Island. The objects of the investigation were twofold. First, to determine the average normal values of the vertical (Z) and horizontal (H) force components of the Earth's magnetic field in that part of the harbour which would be occupied by a ship in passing over the coils, and second, to determine the average normal values of Z and H in the vicinity of Careening Cove, Garden Island.

The samples of chalk examined for a micro-fauna came from two localities in the Dandaragan district: "Kayanaba" Station and "Chelsea" Station. The material yielded numerous fairly well preserved tests of foraminifera and ostracoda referable to Upper Cretaceous species. The results of the examination are recorded in this report.

This report deals with the results obtained in tests with the electrical resistivity method on the brown coalfields at Morwell and Traralgon, Victoria, in an attempt to develop a rapid method of determining the presence of the coal and its depth below the surface. These tests were carried out in the latter part of 1943 by the Geophysical Section of the Mineral Resources Survey at the request of the Victorian Electricity Commission. Thirty-four resistivity-electrode separation tests were made over a wide variety of geological sections in the parishes of Maryvale, Hazelwood and Loy Yang. These tests were preceded by a number of tests by specific resistivity made on various types of overburden and on coal exposed in the open cuts at Yallourn. This report discusses the results of these tests although verbal information concerning them has already been made available to the Commission's officers. It will be shown that under certain conditions, the predictions of the depth to coal are reliable within fairly narrow limits while under other conditions the predictions are misleading. It is proposed in the first instance to outline the method and apparatus used in these tests. In addition, it is considered advisable to outline the methods of interpretation employed in order that the conclusions reached will by fully appreciated. In addition to discussing the resistivity results, the report deals briefly with the possibility of using gravity methods on the same prospecting problem. Calculations have been made of gravity anomalies to be expected from certain coal sections and it is shown that under favourable conditions this might prove of value in determining the presence and position of the coal.