Second annual report for the period 2 June 1996 to 1 June 1997 for EL's 9022 - 9025, 9325 - 9327, 9570 Helen Springs Project

Abstract

The Helen Springs project area is located approximately 120 km north of Tennant Creek, NT and is bisected by the Stuart Highway. The area covers mid-Proterozoic sedimentary and subordinate volcanic rocks of the Tomkinson Creek Subgroup, within the Tennant Creek Block. It is suggested that this area represents the southern extension of the McArthur Basin, host to HYC Zn-Pb-Ag deposit. Zircon dating confirmed an HYC equivalent age (1640 Ma). Regional stream sediment sampling in the previous field season delineated base metal anomalism warranting follow up work. Extensive soil sampling in the Bootu Creek area exposed anomalism in Cu, Pb and Zn (455 ppm, 1140 ppm and 292 ppm respectively). Willieray area soils returned disappointing results, Rock chips from Bootu Creek also produced very high assays (1.5% Cu, 2.6% Pb, 46.9% Mn), however Willieray was again disappointing. A GEOTEM survey was flown to cover both the Bootu Creek and Willieray area. Four 'priority one' anomalies were delineated, 2 at Willieray and 2 at Bootu Creek. Ground EM was carried out over all four anomalies. Initially 4 drill holes were sited on EM targets. The 2 holes at Willieray intersected clay-rich deep weathered zone, the clay interpreted as the source of the conductors. Two diamond holes were drilled at Bootu Creek targeted on EM anomalies. Both intersected massive Mn at modelled conductor depths. Downhole logging of these holes confirmed the Mn as the source of the conductors. Elevated base metals were encountered in chalcopyrite- galena- and pyrite-bearing, carbonate veins within a black shale unit. Scavenging of these metals by the Mn higher in the sequence explains the anomalous base metal content in the surface sampling. Follow up of the Mn intersection in the eastern drill hole at Bootu Creek was carried out. Four percussion holes were drilled results from which suggest the Mn body is stratigraphic, has at least a 400 m strike length and a likely strike length of 5 km. Also based on EM modelling, it is likely the ore occurs as multiple lenses, occurring over a width of 1 km. Potential exists for a high tonnage, low - medium grade Mn resource. An airborne EM survey was completed over the titles. EM anomalies in EL 9022 and EL 9025 were followed up by ground EM drilling. Minor Mn was intersected in EL 9022. Results from the Redwing and Rossi areas (EL 9025) were more promising with economic manganese grades being intercepted. Base metal anomalism at surface attributed to manganese scavenging.