This report describes a geophysical survey made in May 1952 and August 1953 at the Silver Valley mine workings, near Inverell, N.S.W. From the workings there is evidence of mineralisation along a well-defined fissure and one ore shoot has already been partly developed. The survey was made in an attempt to locate other ore shoots of sufficient size to warrant mining operations. Self-potential, magnetic and electromagnetic methods were used in the survey. The self-potential method showed a well-defined anomaly on the eastern extension of the fissure, indicating that a small body of sulphides may exist there with its centre about 300 feet east of the known ore shoot. The magnetic and electromagnetic results showed no pronounced anomalies which could be correlated with any defined ore shoot. Recommendations are made as to how the self-potential anomaly could best be tested. These comprise sinking a shaft at the centre of the anomaly, extending an existing adit, or driving a new adit from a point nearer the anomaly.

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A geophysical survey, comprising self-potential and electromagnetic methods, was made during the 1952 and 1953 field seasons at the Labour Victory Copper Mine, about 7 miles north-north-west of the Mt. Elliott Copper Mine, near Selwyn, Northern Queensland. The self-potential survey covered an area of 2,400 feet x 900 feet, but owing to other operational commitments during the 1953 season, the electromagnetic survey was confined to the southern part of the area. The primary object of the work was to determine the extent of the mineralisation associated with the known lode, which strikes north-south through the centre of the surveyed area. The self-potential survey revealed a well-defined anomaly nearly 1,000 feet long, in the northern part of the area. The axis of this anomaly is parallel to, but about 75 feet west of, the known lode. The disused main shaft of the now idle mine is at the southern end of the anomaly, which in this vicinity deviates slightly towards the south-east, i.e. towards the known lode. No workings exist in the area of the indication, and no outcrops were found, the rock formations being hidden for the most part by alluvium. The electromagnetic results confirmed those of the self-potential survey, but the electromagnetic indication extends farther to the south. The results suggest that the indication may be caused by lenticular bodies and that these are disturbed by cross faults. No mineralised deposits were indicated by the electrical results in the southern part of the area. It is recommended that some trenching and geological and geochemical work be done in the area of the strong electrical indication. If the results of the testing show that the indication is not due to graphitic or pyritic schists, it is recommended that a number of diamond drill holes be put down. Suggested locations for five such drill holes are given. If the anomaly is due to ore the geophysical results suggest an ore body of considerable size.

In response to applications by the Tasmanian Department of Mines and the interested company, Eagle Metal and Industrial Products Pty. Ltd., Tasmania, a geophysical investigation, including self-potential, electromagnetic and magnetic surveys, has been made over the copper-nickel deposits of the North Dundas Field, situated about 5 miles north-east of Zeehan, Tasmania. The nickel ore occurs in the foot-wall of north-striking ultrabasic dykes. The ore shoots already worked had proved very rich but quite small. Important results were obtained in the Cuni North Area only. Conductive indications which appear to be due to mineralization extend over a length of 800 to 1000 feet. The line of mineralization is intersected by cross faults. Drilling targets for five short diamond drillholes are given. Further exploration should be confined mainly to this area. The geophysical results indicate that mineralization farther south is limited in extent and perhaps of no economic interest.

Results are given of a geophysical test survey made at three localities on the Newcastle coalfield in August, 1952, to determine whether intrusive doleritic dykes could be located by the magnetic method. Knowledge of the position of the dykes would assist in planning the lay-out of underground workings and of surface roads. The results showed only slight variations of the magnetic field, but some weak anomalies of less than 100 gammas were recorded. The position of these anomalies coincides with the inferred position of the basic dykes near the surface. The variation in the shape of anomalies suggests non-uniformity of the magnetic properties and shape of the dykes. The magnetic method might be helpful in determining the position and extent of the dykes beyond the areas where they are known, but supporting evidence from other geophysical methods such as the gravity of electric resistivity methods may be needed to verify the magnetic results.

Self-potential and magnetic surveys made in the vicinity of the Mount Cleveland Tin Mine, near Waratah, Tasmania, are described and discussed. The first survey, which is described in Part I of this report, was made in April and May, 1953, at the request of the Department of Mines, Tasmania. The object of the survey was to ascertain whether geophysical methods could detect the known area of mineralisation and, if so, whether any additional areas of mineralisation could be discovered. Results of the first survey show that the geophysical anomalies, particularly the self-potential ones, coincide with the old mine workings. The anomalies over Luck's and Hall's workings, however, cover larger areas than the actual mine workings, thus indicating that further sulphide mineralisation may exist beyond these old workings. Anomalies not related to the old workings appear in an area north-west of Deep Creek, between traverses O and R. Both self-potential and magnetic methods revealed anomalies along these traverses between 350.E and 650.E, where geological investigation has also shown mineralisation to exist. Based on the results of the first survey, the grid was extended and surveyed to the north-east and south-west in March and April, 1954. This second survey, which is described in Part 2 of the report, shows that the anomaly connected with Henry's workings does not extend to the north-east, but terminates sharply between traverses P and Q. Some additional anomalies were recorded in the north-eastern extension of the grid, but in the south-western extension there was no geophysical evidence of mineralisation. It is suggested that further mining exploration work should be concentrated mainly near the former mine workings and in the area to the north-west of Deep Creek, between traverses O and R. Some prospecting trenches should also be put down to test the minor anomalies in the north-eastern part of the area.

The geochemical map (copy attached) prepared by Mt.I sa Mines Ltd., has been compared with plans showing the self-potential and electromagnetic results of the geophysical survey carried out at the Labour Victory Mine, near Selwyn, Queensland in 1952 and 1953. (Plates 4 and 7 of B.M.R Records 1954, No. 2). Transparencies of these two plates are also attached.

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This report presents the results of detailed geological mapping of an area of approximately seven square miles surrounding the Mount Elliott copper mine, Selwyn, Queensland. The survey was made to determine the relationship between the geological structure and the mineralized zone containing the Mount Elliott copper deposit. A geological map of the actual exposures has been compiled (Plate 1) and interpretations of this data are shown on one plan (Plate 2) and eight sections (Plates 3, 4, 5 and 6). This report is intended as a supplement to the report by C.J. Sullivan (1951) and should be read in conjunction with it.

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