Annual report on EL 4183 Cox Peninsula for 1987 NT.

Abstract

During the 1986/87 work programme a number of pegmatites were investigated in detail including exploration trenching and sampling and auger drilling. A trench was cut into the banks of the East Charlotte River to test for mineralized alluvium. A 6 m deep 57 m long trench was cut. The sampling procedures for alluvial and pegmatite deposits have been described in previous reports. Similarly the preconcentration and assaying techniques have been comprehensively described in previous reports. Work carried out at various location; Ah Bung - A total of 190 m of costeaning was completed over the old workings. Auger drilling totalled 134.5 m. Ah Hoy Pegmatites - During 1986 a further 278 m of costeaning was completed over outlying pegmatites and the strike extensions of the western and eastern pegmatites. Auger drilling totalled 1910.5 m of which 807.5 m was drilled in the eastern pegmatite and the remainder in the western pegmatite. Kelly's Prospect - A total of 252 m of auger drilling was completed. Mammoth Prospect - A 25 m grid was placed over the prospect and 155 m of costeaning was completed. Auger drilling totalled 206.5 m. Mammoth Extended - The prospect has been mapped at a scale of 1:500 and 51 m of trenching completed. East Charlotte River -A single costean (57 m) was dug across the narrow channel immediately east of the crossing. The trench is downstream from the Booths drainage outlet. Seven samples were collected from the wash horizon on the northern and southern sides of the channel and returned turned grades ranging from 0.013 kg/tonne SnO2 and 0.003 kg/tonne Ta2O5 to 0.099 kg/tonne SnO2 and 0.027 kg/tonne Ta205. Mineralisation is associated with the present channel, which remained unsampled due to sub-surface water, and a single sample 20 m north of the channel returned a grade of 0.105 kg/tonne Sn02 and 0.025 kg/tonne Ta205 (1.5tonne/LCM), otherwise grades are sub-economic. Additional systematic trenching in the area will substantiate the grades recovered to date. Of the pegmatites explored in 1986/87 the Ah Hoy and Kelly's deposits showed the most promise for productive tonnages and grade. Ah Bung was found to be a narrow vein system with little tonnage potential and Mammoth and Mammoth Extended were essentially unmineralised pegmatites. Initial trenching of the East Charlotte River produced promising results. This drainage will be the subject of more detailed investigation during the 1987/88 season.