During the intial two years (1972 - 1974) of exploration at Telfer, water require- ments were limited to supporting a 50 man camp and diamond drilling to verify thickness and grade of the stratabound ore deposit. Water bores were drilled to intersect the Middle Vale Reef down dip from its outcrop about 70 metres below surface. The MVR reef is an oxidized pyritic horizon which contains 30% - 65% sulphide below the zone of oxidation and forms a highly porous leached gossanous zone to a depth of 100 metres. Surface run-off water from the low hills associated with the Main Dome structure have led to annual re- charge of this extensive aquifer which MAP AREA Lake Waukarlyearly Permian rocks Precambrian basement - - ~;; rocks Sand d.n.s p. __x000D_
Drainage sg 1 qo~ (`-~.~ ? ;+ Palaeochannel and 1 d {- subsurface drainage % GLENN BOREFIELD PASSMORE FAULT ;TsI1. G-OId MIns BOUNDARY oChr~st as t .` Pool 4, 1 j`` Lake Dora t ~daN 22' 0, 50 Niter KILOMETRES Fig 1. Telfer district map, Great Sandy Desert, Western Australia.