De Grey needs a bigger drill rig after confirming major Pilbara gold discovery
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Special Report: Seven follow up holes at the Hemi prospect have intersected thick, high-grade gold mineralisation on two sections 640m apart. This thing could be big.
The untouched Hemi prospect was discovered mid-December under a shallow ‘blanket’ of transported cover.
Maiden thick and high-grade results like 12m grading 9 grams per tonne (g/t) supported De Grey’s (ASX:DEG) theory that its rapidly growing — but grossly underexplored — 1.7-million-ounce Mallina Gold Project in the Pilbara hosted numerous large deposits.
For any discovery, things like orebody depth, grade, and thickness of mineralisation all play a massive part in measuring potential gold production costs.
Now, results from the first seven follow-up holes at Hemi have intersected this thick, high-grade zone on two sections 640m apart.
‘Section A’ is 30m wide and starts 30m below surface. Importantly, the deepest hole (so far) has intersected the highest grade to date of 24m at 7.5g/t and finishes within the gold zone. So the drilling has already established the gold is 130m deep!!!
This depth is at the limit of penetration for the aircore drill rig. So De Grey needs to wheel in the bigger RC and diamond rigs.
On Section B, drilling defined a zone of oxide mineralisation about 20m thick immediately beneath 30m of transported cover.
Significant results include 24m at 4.2g/t from 36m but aircore drilling could not penetrate any deeper as the ‘intrusive’ rock is harder in fresh rock.
Hence the gold zone at both A and B remains untested and entirely ‘open’ in multiple directions.
Larger capacity reverse circulation (RC) drilling is now required to test deeper across Sections A and B.
Larger capacity RC and diamond rigs are now being mobilised to site for deeper and more detailed drilling, with the view to establishing an initial resource at Hemi.
At this stage, De Grey believes that Section A and Section B are linked. However, several mineralised structures could exist.
For an exploration geologist, these results are both satisfying and exciting, says De Grey technical director Andy Beckwith.
“Hemi’s shallow high-grade gold zones provide an excellent opportunity to increase resources and further de-risk our path to production,” he says.
“The individual assays down hole are very robust, creating solid high-grade gold zones over considerable thicknesses which we expect to continue at greater depth.
“We currently interpret the two 640m sections are structurally related, suggesting we could be drilling a major new gold discovery.”