Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Superficial deposits of ferruginous manganese ore occur on the southern end of the Teano Range, Peak Hill Goldfield, Western Australia at about 150 miles by road north-north-west from Meekatharra. During the course of an investigation of new manganese discoveries in north-west Western Australia by L.E. de la Hunty of the Geological Survey of W.A. and the writer, the opportunity was taken to inspect two groups of small deposits in the Teano Range. One group contains about 14,200 tons of ore which averages about 2 per cent manganese and 32 per cent iron, and the other group 4,000 tons of marginal grade containing about 46 per cent manganese and 3.5 per cent iron. The former group is not of marketable quality and the other is too small and too remote to be of commercial value.

This prospect is situated on the northern bank of the East Finniss River, approximately 500 yards north-east of Brown's workings and 800 yards south-west of White's workings. About 50 years ago the area was prospected for copper and abandoned after several costeans had been dug. A small radiometric anomaly was discovered in 1950 and the area was radiometrically contoured. A geological map on a scale of 20 feet to one inch was prepared by the writer during the 1951 field season, and accompanies this report (Plate 1). [Geology, structure, mineralization, workings, diamond drilling, and prospecting recommendations are discussed].

The Crater Prospect is situated about 4 miles south-south-east of White's workings and 1 mile north-east of the junction of Batchelor Road and the Darwin-Birdum railway line. It is the name assigned to a type area of an extensive radioactive bed of conglomerate. Low grade but wide-spread radioactivity was discovered by R.S. Matheson and D.F. Dyson (geophysicists) in June 1951, while prospecting along the sedimentary beds out-cropping immediately south of the Rum Jungle granite on the south-side of Giant's Reef fault, and on the south side of another major parallel fault. Geiger-Muller traverses along the strike of a grit-conglomerate horizon away from the Crater prospect revealed that the radioactivity extends westwards for 1.5 miles and for half a mile to the east. The radioactivity, which was confined to the conglomerate, was low-grade and discontinuous over this distance of 2 miles. The Crater Prospect, which can be regarded as a type locality, was geologically mapped by the writer on a scale of 200 feet to one inch after the area had been radiometrically contoured, and the plan accompanies this report (Plate 1). [The geology and structure of the prospect, nature of the radioactivity, and prospecting recommendations are discussed].

This report covers the work carried out by the author who was the geophysicist in charge of seismic and magnetic work conducted on Macquarie Island during 1951-52. It deals mainly with the preparation of and repairs to huts, the continuation of the seismic recording programme and the installation of a magnetic recorder. Although scientific achievement was not outstanding, the way has been prepared for a successful observing programme in the future.

A geological investigation of the Yeuralba mineral field was undertaken by the Bureau of Mineral resources as part of the field activities for the 1952 field season. Actual field work occupied five weeks in August and September. Most of this time was devoted to sampling individual greisen occurrences. In addition, a geological map of Yeuralba and the surrounding area was prepared on a scale of 1:25,000. Sandstones and tuffaceous sandstones of Lower Proterozoic age have been folded and intruded by porphyry, epidiorite, and granite, in the Yeuralba area. The granite intrusion was followed by a strong tensional movement and a regional system of black faults and strong joints was developed. Lower Cretaceous sandstone and porcellanite unconformably overlie the igneous rocks and Lower Proterozoic metamorphics. The granite has been hydrothermally altered to a marked degree along these fractures. Tin, tungsten, gold and bismuth mineralization is associated with greisen, tourmalite, topazite, and other alteration products of the granite. Cassiterite-bearing tourmalites and assiterite-wolframite-gold-bearing topazites and tourmalites occur within the granites mass and wolframite-scheelite-bismuth-bearing greisens at the contact between the granite and the sediments. Bulk sampling and preliminary grab sampling of a number of these bodies indicates that several of the bodies should be tested in a more detailed manner, to determine whether they will bulk at a grade which would permit economic mining of the deposits.

The activity of Mount Lamington over the last half year has tended to confirm conclusions drawn from earlier observations, namely, that conditions of slow decline in overall activity pointed towards a return to the dormant state. There have been fluctuations in activity during this period, renewed dome building in some sectors of the crater and on one occasion, explosions were reported to have occurred near the dome summit.