Report on permian foraminifera in core samples obtained from bores at Coorabin, 1942-3.

This progress report follows a general report on the Wymah field by N.H. Fisher and C.L. Knight, submitted in June, 1942. It contains details concerning the development, ore structures, and mineral reserves of the Wymah wolfram mine.

This report is written chiefly to present estimates of reserves of bauxite proved to date in Gippsland. Consequently, discussions of the geological aspects of the investigation, though essential to an understanding of the subject, are kept to a minimum. The existence of bauxite in the neighbourhood of Boolarra and Thorpdale, County Buln Buln, South Gippsland has been known for some years and bauxite from Nahoo, Allot. 8 Ph. Narracan South, has been used for chemical purposes for over 20 years. Eleven additional discoveries were made from time to time up to April, 1942, when an extensive prospecting programme was undertaken. In the short time that has elapsed since then a further twelve deposits have been discovered, making a total of twenty-four deposits in the adjoining parishes of Moe, Allambee East, Narracan South, Mirboo and Budgeree in the county of Buln Buln. Several of these deposits have been systematically tested by shaft sinking and boring. This exploration is still in progress.

The presence of muscovite on Yinnietharra Station in commercial sizes and qualities has been known since 1913, but little active development was carried out in the locality until 1926, when a syndicate, formed in England, took up leases and began operations. Activity lapsed the following year, but desultory prospecting more recently has led to the production of a few small cases of spotted mica, some of which was sold in Melbourne in the early part of 1942. The deposits described hereunder are shown on the accompanying locality map, Plate 1. At this stage only brief references are made to deposits containing stained and spotted mica unsuitable for critical electrical or radio applications.

A description of the mica deposits inspected.

Mullalyup is a small village about 140 miles south from Perth and 33 miles by rail south-east from Bunbury. The main highway between Perth and Bridgetown passes through the village. The region is occupied by Basement rocks which appear to consist mainly of schist and gneiss. The regional strike is about north-west. The hill slopes and lower levels carry a heavy cover of soil and the hilltops are mostly covered with laterite and, in places, high-level gravels. These gravels are widely distributed in this region. The mica occurs, as usual, in pegmatite dykes, and five such deposits are shown on the attached plan. Some difficulty was experienced in locating these deposits owing to the thick undergrowth and hill terrain and it is probable that other pegmatites exist in the locality. Search was confined mainly to the slopes and it was considered that soil in the valleys and laterite on the hill tops would obscure outcrops of any pegmatite dykes, except at intermediate levels.

Ajana is 66 miles north from Geraldton by rail and is the terminus of the branch railway which passes through Northampton mining district. Aspects of regional geology and mineral occurrence are discussed in these notes.

In view of the shortage of tungsten supplies in allied countries, efforts are being made in Australia to increase production with a view to not only satisfying domestic requirements, but also exporting to Great Britain and the United States of America. The King Island scheelite mine is at present the largest producer of tungsten ore in Australia, and the possibilities of increased production from it were, therefore, among the first to be considered. Geological and geophysical surveys were made in June and July, 1942. A preliminary report was prepared in September and a drilling campaign drawn up to test the deposits with the object of proving sufficient ore-reserves to justify increased production for war purposes. Up till the present, fifteen drill holes have been completed and under a modified programme four remain to be drilled (two of these are in progress). This second preliminary report is based on the drilling and assaying results to date (details of thirteen holes are available).

This collection of fossils was made by Mr. H.J. Cook, Supervisor of the Lakes Entrance project during December, 1942. It consists chiefly of broken specimens of molluscan shells, the most important being a fragment of large Mitra, Fulgoraria ancilloides (Tate) and an almost complete specimen of Cypraea consobrina (McCoy). The importance of the discovery of the latter species is discussed in the report on my recent visit to the shaft, but the presence of the former (which had previously only been recorded from the Balcombian and has a length of 110 millimetres) in the present collection, again indicates that valuable information has been lost through inadequate sampling of a rich shelly zone in the Kalimnan stage.

No. 27 Bore, Mirboo North, is one of a series of bores being drilled in that area to prove the extent of the bauxite deposits. This report describes the results of a microscopic examination of the samples taken from this bore. Samples were taken from between the depth of 0 to 83 feet.