The geophysical expression of the Lone Sister deposit is a coincident magnetic low-resistivity high due to the rhyolite dome. As with the 309 deposit, it is also associated with a negative chargeability due to severe EM coupling or current channelling probably related to the contact.
Exploration to date has been directed towards delineating near-surface mineralisation in order to justify open-pit mining. However, the model for Lone Sister envisages a host felsite dome with disseminated and marginal mineralisation and steep plunging ore shoots which are interpreted to have been derived from a deeper intrusion source. The main breccia zone and eastern vein-breccia zone may be hosted in flexures in through-going structures and so these steep plunging ore zones display potential to continue to depth. At present the resource drilling extends to only 250m below surface. The potential for increasing the high grade resource is favourable and deeper drilling is required below the fluidised breccias hosting the high grade resource. Geophysics, geochemistry and mapping should be extended to detect other buried intrusions that may be similarly mineralised.
Intersections > 5 g/t Au in drill holes at Lone Sister at tabulated below. Some spectacularly high grades have been intercepted, especially below 200m down hole in LRCD 15.
|
