Eagle zone’s latest high-grade results from infill and extensional drilling at Hemi  – part of De Grey’s Mallina gold project in WA – have highlighted the potential for underground mining.

DeGrey Mining says the gold mineralisation is similar to what’s been turned up at adjacent deposits of Aquila, Brolga, Crow, Falcon and Diucon.

And like Diucon, Eagle shows a strong structural overprint which can carry high gold grades and occasional visible gold.

New results include:

  • 53.0m at 5.8 g/t gold from 315m including 3.6m at 76.6 g/t gold from 339.4m (HERC955D) extending mineralisation around 100m below the maiden mineral resource estimate (MRE)
  • 51m at 6.3 g/t from 106m including 0.6m at 143.5 g/t from 147m and 1m at 142.0 g/t from 150.0m (HEDD103) extending mineralisation approximately 40m to the south of the maiden MRE
  • 60.8m at 2.7 g/t from 41.2m including 1m at 36.4 g/t from 68m and 1m at 72.9g/t from 73m (HEDD202); and
  • 7m at 16.5 g/t from 132m including 2m at 55 g/t from 136 m (HMRC010) to the east of Eagle

Moreover, extensional drilling in the northwest of Eagle continues to intersect mineralisation including 31m at 2.1 g/t from 155m and 19m at 1.8 g/t from 192m (HMRC229).

The company says this confirms potential new lodes approximately 240m north of Eagle.

Underground mining below pit designs

De Grey Mining (ASX:DEG) general manager exploration Phil Tornatora says the high-grades add the potential for underground mining below the proposed Eagle pit designs.

“Resource extension and definition drilling at Eagle has continued to identify high grade mineralisation associated with quartz-carbonate veining, sericite-albite alteration and visible gold.

“A zone of high-grade intercepts at Eagle has now been intersected on several sections over a strike length of around 200m, and a down dip extent of at least 250m.

“Drilling in progress may expand the extent of high-grade mineralisation…. geological studies are continuing; however, the high-grade mineralisation may represent a structural overprint on earlier intrusion hosted sulphide mineralisation.

“These high-grade zones have the potential to positively impact Eagle pit shell optimisations, mining and processing schedules and significantly adds to the potential for underground mining below proposed pit designs,” Tornatora adds.

De Grey Mining
New pit shell optimisations to be conducted as part of the PFS are expected to extend the scoping study open pit mine design.

Resource definition and extension drilling ongoing

The company has prioritised resource definition drilling to a 40m x 40m spacing above 400 vertical metres to increase the resource confidence level from JORC Inferred to Indicated in areas of Eagle where plans are afoot to mine by open pit methods.

Resource definition drilling for the PFS will continue into the first quarter of 2022, and new pit shell optimisations are expected to extend the scoping study open pit mine designs.

“Resource definition drilling at Eagle to increase the resource confidence from JORC Inferred to Indicated is continuing so that the Eagle resource can be included in the prefeasibility evaluation,” Tornatora says.

“Eagle was not included in the Scoping Study ten-year evaluation period.”

Resource extension drilling at Eagle will continue throughout 2022.




This article was developed in collaboration with De Grey Mining Limited, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.