Gascoyne Resources Ltd (ASX:GCY) has proven the potential of the Gilbey’s North Prospect of the Dalgaranga Gold Operations in Western Australia with down-dip extensional drilling returning an “exceptional” result of 32 metres at 8.58 g/t gold from 167 metres downhole with a higher-grade component of 14 metres at 16.4 g/t gold.
This drill hole (DGRC1026) was collared at a 45-degree angle, further to the northeast of a previous high-grade intercept of 54 metres at 6.55 g/t gold (DGRC0971), designed to test the orientation and true width of the gold system.
Northerly system extends further than expected
“Our strategy to extend the mine life at Dalgaranga is well on track,” Gascoyne Resources managing director and CEO Simon Lawson said.
“We engaged our people to help define our future and we made a significant discovery with the drilling of the northerly extension to the Gilbey’s system earlier this year.
“What we initially discovered was a high-grade, relatively narrow extension to the 'G-Fin' lode system seen in the northern end of the main Gilbey’s pit. This was a significant discovery and showed us that Dalgaranga has a lot more to offer than some may have believed.”
This latest gold result originated 30 metres beneath the previous high-grade intercept, illustrating the down-dip potential of the prospect as well as the high consistency of mineralisation at depth.
More drilling needed to define system
“As we systematically drilled further north on the G-Fin extension we also drilled through what appeared to be a hanging-wall mineralised zone which we initially thought may run parallel to the trend of the main kilometre-long northerly-striking Gilbey’s mine sequence,” Lawson continued.
“Further drilling of this hanging-wall zone shows that it actually strikes at almost right angles, or east-west, to the strike of the initial north-south footwall or G-Fin extension discovery.
“As a result, we have just drilled seven new holes north-south to assist in defining the potential true width and extent of this new system.”
Gascoyne has mobilised seven reverse circulation (RC) drill rigs to Gilbey’s North to test the 'true width' of the mineralised system, drilling at a 45-degree angle to the north of drill hole DGRC1026 and a 90-degree angle north of drill hole DGRC0971.
Assays from these holes have been fast-tracked and are expected shortly.
Broad zone prospective for gold mineralisation
“Given the consistently high-grade of the east-west mineralised zone, it is imperative that we understand the potential volume of this new mineralised zone as it will have a significant impact on our initial mineral resource estimate for Gilbey’s North,” Lawson said.
“What we believe we are seeing is a regional-scale east-west fault system interacting with the typically stratigraphic-hosted north-south Gilbey’s mineralised system.
“The intersection point between the east-west structural plane and the north-striking stratigraphic host, otherwise known as an ‘intersection lineation’ creates a broad damage zone where gold has precipitated and/or been remobilised and enriched in this area.
“Proving the intersection lineation model is an important development for us as we have seen a number of smaller offsets throughout the main Gilbey’s mine sequence that may represent similar opportunities.
“Regionally there are also a number of existing high-grade prospects that appear to line up with our structural projections and may prove to be part of the same mineralisation model.”
Several other holes at Gilbey’s North have yielded notable gold results, including:
- 31 metres at 4.68g/t gold from 132 metres, including 5 metres at 18.1g/t gold;
- 26 metres at 3.05g/t gold from 150 metres, including 2 metres at 14.2g/t gold; and
- 2 metres at 12.13g/t gold from 133 metres, including 1-metre at 22.7g/t gold.
Finally, Gascoyne is working on a maiden mineral resource estimate for Gilbey’s North, but has delayed publication until late August in order to incorporate several recently drilled assays which are pending.