De Grey Mining Limited (ASX:DEG) expects to increase its 1.2 million ounce gold bounty at the Pilbara project in Western Australia after receiving high-grade results from recent drilling.
A new estimate is being prepared to include recent results from the Amanda and Amanda East deposits at the project, which is 60 kilometres south of Port Hedland.
Best result from the reverse circulation (RC) drilling at Amanda is 14 metres at 4.94 g/t gold from 19 metres, including 6 metres at 10.85 g/t from 20 metres.
Amanda East returned a strong result of 23 metres at 1.35 g/t from 10 metres, including 6 metres at 3.93 g/t from 20 metres.
This was the first detailed drilling carried out at the Amanda deposit since 2007 and has provided improved understanding and upside potential.
READ: De Grey Mining’s drilling expands high-grade gold footprint at Pilbara project
There were 16 holes drilled at Amanda for 978 metres and 17 holes at Amanda East for 1,092 metres.
The drilling was part of an infill and extensional RC program targeting improved and additional resources at the Mt Berghaus, Mallina, Toweranna and Amanda deposits.
At Amanda, mineralisation is open at depth and along strike to east and west, as well as the 500 metres of strike between the Amanda and Amanda East zones.
High-grade results
Other high-grade Amanda zone results are:
- 12 metres at 1.46 g/t from 14 metres, including 6 metres at 2.62 g/t from 18 metres;
- 13 metres at 1.23 g/t from 37 metres; and
- 15 metres at 1.00 g/t from 34 metres.
Amanda East also returned:
- 7 metres at 2.84 g/t from 9 metres;
- 7 metres at 2.39 g/t from 38 metres;
- 7 metres at 2.22 g/t from 43 metres; and
- 12 metres at 1.34 g/t from 16 metres.
To date, De Grey has defined more than 1.2 million ounces of gold across the 1,480 square kilometre Pilbara project, including 35,400 ounces at the Amanda deposit.
Many anomalies are untested
Only 10% of the 200-plus kilometres of mineralised shear zones have received detailed shallow RC and diamond drilling to a nominal depth of 100-150 metres.
There are more than 40 identified yet untested soil anomalies along the highly prospective regional-scale shear zones and conglomerates.
The Amanda deposit is within the Tabba Tabba Thrust, which also hosts the 287,700-ounce Wingina deposit 8.5 kilometres to the southwest.
Whilst Amanda and Wingina are essentially outcropping, limited detailed exploration drilling has occurred along the intervening strike length where mineralisation is outcropping and undercover.
The Edkins prospect is a prime example where previously reported high-grade RC drilling results of 2 metres at 43.2 g/t, 3 metres at 29.3 g/t and 3 metres at 7.3 g/t have not been followed-up.
Future work programs
Planning is underway for more systematic aircore/RAB drilling traverses targeting mineralisation masked by the thin veneer of sand cover, together with more detailed mapping and sampling of outcropping ridges along the Tabba Tabba Thrust.
As well as this drilling and preparation of a resource estimate, De Grey also proposes open pit mining optimisations as part of a pre-feasibility study economic assessment.
Infill RC drilling is also proposed between the two deposits utilising a specialised track-mounted RC rig capable of drilling shallow angled drill holes in areas where access for larger drill rigs is limited.