EL 4226 Howley project area evaluation of gravel resources

Abstract

Exploration work in EL 4226 has been directed toward the further evaluation of the gold bearing gravels in the main drainage channels and the maintainence of existing tracks and haul roads. Previous exploration work has involved air photo interpretation as part of a regional geomorphological study (see previous reports on EL 4226, particularly 20/1/88) . Follow up pan and rock sampling was carried out with encouraging results. Gravel volumes were estimated from a few pits, old diggings and creek incisions and these have been revised as the work has proressed. Present estimates of the gravel resources are as follows: The main gravel resource occurs in 'Elbow Creek' which drains northwestward from Metro ('Big') Rowley along the western side of the EL. Previous estimates are now considered to be somewhat conservative and have been upgraded from 104,00GM3 to 130,000W. Little further work has been done on the evaluation of grade and an average value of 0.4g/LCM still stands. A possible palaeochannel was mapped north of Metro Rowley which may have carried a resource of 12,500W of good grade gravels. However, although the channel may well exist, it now seems unlikely that it contains any auriferous gravels beyond a few small lenses. Most of the valley fill is barren colluvium. Large gravel spreads are associated with the creeks draining northeastward in the northern part of the EL. These gravels are barren due to the position of the watershed which lies to the east of the mineralis,ed anticlinal axis in the northern half of the EL. However, in the southeast, headwater tributaries of Dam Creek drain eastward off the anticline at Metro Howley. A low volume (45,000W ), high grade (0.4 to 0.5g/LCM?) series of deposits was mapped in these creeks previously (20/1/88) and nothing further is added to this conclusion here. However, grades are difficult to evaluate from sampling as in this topographic position, the gold content of the gravels appears to be quite nuggety. RECOMMENDATIONS - Ideally, grade testing and pitting is required ahead of mining operations. Attention should continue to be focussed on Elbow Creek. A programme of random pitting is required to test grades in the hard lower and loose upper gravels as mining proceeds so as to select the best grade material. The Dam Creek tributaries in the southeast of the EL likewise require further test pits although this must be done in conjunction with the work on the main part of the creek system in the adjacent EL 4847. The existence of economic grade gravels in Elbow Creek and Dam Creek is assured by exploration work and the resource is ready to be mined subject to the above conditions.