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.

A description of the mica deposits inspected.

The Chilcot copper mine is situated 15 miles south-south-west from Orange, from which it may be reached by reasonably good road. It was examined during 1942 by Dr. N.H. Fisher, Chief Geologist, Mineral Resources Survey, who recommended that a geophysical survey be made to search for additional ore shoots along the lode channel (1942/020). The geophysical survey was made during the three weeks ending 19th December. Operations were commenced over the area north-east of the mine, extending a distance of 550 feet from the mine, thus covering the part favoured by Dr. Fisher for extension of the lode channel. Later the survey was extended a similar distance to the south-west and the north-eastern part was extended a further 150 feet. Methods used comprised geomagnetic, spontaneous, polarisation, electro-magnetic and potential ratio. Traverses were placed at 50 feet intervals and observations by the various methods were made at intervals of 25 feet and, in some parts, at closer intervals. The results of this survey are discussed herein.

This report follows a preliminary report dated 9th September, 1942, and it is not proposed to recapitulate the matter contained therein, although some references to the preliminary report are necessary. The principal purpose of a second visit to the Lakes was to determine accurately the area of useful salt-bearing surface and the nature of the beds. Much evidence confirmatory of the views expressed earlier regarding the structure of the lake beds was noted. However, a plane-table survey revealed that the total extent occupied by recoverable salt is considerably less than a casual inspection would suggest and consists of the following areas, which are shown on the accompanying plan.

Bore No. 3797 on A. Holmes' property is situated about 25 miles north-west of Bore No. 3785 on W.R. Johnston's property reported upon 12/11/41, 19/1/42 and 11/3/42, and about 20 miles north of Bore No. 3752 on G.M. Taylor's property reported upon 1/9/41. The samples examined are from the depth of 50 feet down to 750 feet.

The country rock of the Coimadai antimony orebodies is Lower Ordovician slate and sandstone, with northerly strike and steep westerly dip. It is intruded by narrow east-west striking pre-mineral porphyry dykes, which dip north and are displaced by or in places form the walls of the lode channels. The antimony lodes are lenticular ore-shoots in fault zones which show signs of intense crushing and shearing, the shoots being usually associated with fault intersections or branches. The workings are divided into two sections: No. 1, Draper's, in which the lode system strikes north-northwest and dips 45-55 degrees west, and No. 2, Bondison's, where the strike is east-northeast and the dip 60 degrees to the north. In No. 1 section most of the ore above the adit level has been extracted, but possibly 400 tons of the 5% Sb, ore have been developed below the level, and prospects of further ore are good. Gold values are much higher in No. 2 than in No. 1 section, but few assay data are available with regard to either antimony or gold content.

The felspar deposit which is owned and operated by South Australian Silicates Co. Pty. Limited was visited on the 13th September, 1943, in company with Mr. Sampson, Secretary, of the Company and Mr. S.B. Dickinson, Deputy Government Geologist of South Australia. A description of the deposit follows in the report.

Two samples of diatomite were recently received from Broken Hill Pty. Co. Limited for microscopic examination. They were from Nettle Creek, 9 miles north-east of Mt. Garnet and near Innot Hot Springs. The results of the microscopic examination are given in this report.

Legacy product - no abstract available

The Womobi wolfram mine is situated in M.I.6798 in the Parish of Thologolong, County of Benambra, one mile east of the main Murray Valley Highway and 42 miles by road easterly from Albury. The mine was mapped on September 4th, 1943. The surface was mapped by plane table on Decemeber 1st, 1943, in company with Mr B.P. Utting, and underground mapping brought up to date. The mine is developed by a short adit to the reef, with drives along the reef system 370 feet east and 240 feet west, the west drive being connected to the surface by another adit opening. A connection has been made to the surface from the east drive at 190 feet from the adit, and two short rises were previously in existence 20 feet or so on either side of the adit. At 30 feet in the west drive a winze was sunk 50 feet and a level has been driven along the lode. Stoping is in progress above this level and above the east level.