Summary of the Frances Creek Iron deposits Northern Territory

Abstract

Hamersley Iron Limited have tested the possibility for further mineralisation to be located in the Francis Creek area approximately 25 km to the north of Pine Creek. This area produced almost 8Mt of iron and phosphorus ore from 1966-1974. Mining ceased due to damage at the port facilities in Darwin and the start up of the Paraburdoo Mine in WA. A brief field reconnaissance of the area and review of the stored diamond core was undertaken to assess the potential of the area. Work to date has consisted of collating the historical data to compile summaries of the drilling, diamond drilling, resources and complete stack sections on selected deposits. During October 1999 a helicopter assisted reconnaissance of the Francis Creek area was undertaken. This work also included rock chip geochemistry on samples from the Helene 6/7 deposit, and diamond drill hole geochemistry. Based on the results of the recent work it is interpreted that the mineralisation was formed from hypogene fluids derived mainly from the intrusion of granites along the southern edges of the better deposits. Later supergene style mineralisation has then overprinted these deposits, possibly helping to leach some of the phosphorus also. Although the material mined and observed in the field is of high quality and grade it would appear that the potential to find more than 20 Mt of further material is extremely low. It is therefore recommended that no further work should be undertaken within the existing area.