Annual Report for the period 29 September 1985 to 28 September 1986 EL 4498 Ranford Hill

Abstract

Ranford Hill, EL 4498, was explored by Australian Coal and Gold Holdings Ltd for tin, gold, diamond and uranium mineralisation in lower Proterozoic inetasedimentary rocks of Pine Creek Geosyncline. Exploration methods employed included gridding; detailed geological mapping at a scale of 1:400; rock chip sampling; stream sediment sampling with analysis of the fine fraction and mineralogical examination of the coarse, heavy mineral fraction; and an airborne magnetometric/radiometric survey. Expenditure in the second year of the Licence amounted to $45,027. The Mary River Camp tin occurrences were gridded and geologically mapped at a scale of 1:400. Data is presented show a complex system of quartz-tourmaline veins, quartz veins and granite dykes with associated tin mineralisation. Tin values of up to 3.3% (REC 147) were from shallow prospecting pits. Further geological interpretation of data is currently being undertaken. Gravels from the drainage areas of the lode deposits were also sampled, with disappointing results. The results concentration of thin horizons of cassiterite at the base of the gravel section, directly overlying basement. Samples were collected from streams in the southern area of the Licence, south of Ross Smith Battery. Heavy minerals from the coarse fraction were mineralogically examined, and economic minerals identified: Samples RH 30,32 and 33 contain discrete grains of gold. Samples RH 29,30,33 and 35 contain cassiterite in greater than trace quantities. All samples should be investigated by further sampling and geological reconnaissance. Geochemical anomalies were also obtained from the -80# of the samples. Samples RH 31 and 33 have anomalous gold values of 0.0llppm and 0.300ppm, while samples RH 30 and 31 have anomalous tin values of l00ppm. These samples should also be investigated in conjunction with follow-up programmes for the alluvial samples. An airborne magnetometric and radiometric survey of 278.8 line kilometres at a flight line spacing of 150 metres was flown by Geoterrex Pty Ltd over the area to the north of and south of the Little Mary River in the northwest portion of the EL. The primary target in this area is gold mineralisation, and geophysical interpretation of the data currently being undertaken by Geoterrex Pty Ltd. The third year exploration programme will consist of follow-up of geochemical, mineralogical and geophysical anomalies outlined in the 1985/1986 field programmes.