De Grey Mining reports further gold hits at Hemi, extends mineralisation of Brolga

by Leena Thomas
Image: De Grey Mining Limited

De Grey Mining Limited (ASX: DEG) announced that the drilling at the Brolga Zone at the Hemi Gold Discovery in Western Australia has resulted in mineralisation extending north towards Aquila and northeast towards Scooby Zones.

The company reported that aircore drilling intersected mineralisation 320m to the northeast of Brolga trending to Scooby. Highlights include 17m @ 1.4 g/t Au from 64m; and 4m @ 3.3g/t Au from 44m.

DEG said that RC drilling extended mineralisation north of Brolga, with significant hits of 40m @ 2.0g/t Au from 36m, 30m @ 1.6g/t Au from 101m, and 5m @ 2.8g/t Au from 142m; and 12m @ 2.9 g/t Au from 36m.

De Grey reported that the metallurgical diamond holes at Brolga returned strong results including HEDD004 with a broad interval at a 0.3g/t Au cut-off grade of 150m @ 1.5g/t Au including 62.0m @ 2.2g/t Au from 47.0m; 19.8m @ 1.8g/t Au from 117.0m; 13.0m @ 2.1g/t Au from 151m; and 15.8m @ 0.9 g/t Au from 170.2m.

The company announced that the RC drilling on 80m line spacing south of Brolga has intersected anomalous mineralisation in intrusive over a strike length of 1km. Intersections include 19m @ 1.2g/t Au from 38m.

Mallina gold project

De Grey’s Mallina Gold Project is located approx. 60km south of Port Hedland in the Mallina Province of Western Australia.

The project hosts numerous large deposits, of which significant gold deposits include Withnell, Mallina, and Toweranna. Other prospects include Hemi, Antwerp, and Scooby.

Hemi prospect

Hemi is a discovery under 30m of transported cover, with two zones of strong, broad sulphide rich alteration with high grade gold mineralisation partially defined in the Aquila and Brolga zones. De Grey had recently defined a third gold in bedrock zone called the Crow zone. Crow is a northeast-trending gold in bedrock anomaly.

Drilling at Hemi

The company had commenced aircore (AC), reverse circulation (RC) and diamond drilling (DD) at Hemi to test and extend the known mineralisation.

DEG said that two aircore rigs are testing for new intrusions or extensions to known mineralisation, while two RC rigs are following up positive aircore results (e.g. Aquila) and providing pre-collars for diamond drilling. De Grey said that two diamond drill rigs are testing for depth extensions and have recently completed holes for metallurgical testwork.

DEG has now announced the drilling update for the Brolga Zone at the Hemi Gold Discovery. The company said that the latest results demonstrate extensions at Brolga to the north, northeast, and south, plus strong continuity of mineralisation within Brolga in dedicated metallurgy holes.

The overall footprint of Hemi is now approximately 2.5km north to south and 2km west to east with three main zones (Aquila, Brolga, and Crow) defined within this large gold system.

Aircore drilling

De Grey announced that a step out aircore drilling is being conducted in all directions around Hemi.

The company said that at Brolga, drilling on a 160m line spacing and 40-80m collar spacing has intersected shallow mineralisation approximately 320m to the east of Brolga.

DEG said that this mineralisation is located along the structural trend toward known mineralised intrusive at Scooby, a further 1km to the north east.

Best results include 17m @ 1.4 g/t Au from 64m in BWAC847; and 4m @ 3.3g/t Au from 44m in BWAC846.

RC Drilling

DEG reported that the RC drilling was conducted to test for extensions to mineralisation to the north, north east and south west of Brolga and to provide pre-collars for deeper diamond drilling into Aquila and Crow.

The company said that the RC drilling has successfully identified more near surface mineralisation at Brolga.

Significant new drilling results north of Brolga include HERC206: 40m @ 2.0g/t Au from 36m, 30m @ 1.6g/t Au from 101m, and 5m @ 2.8g/t Au from 142m; HERC208: 7m @ 3.9g/t Au from 53m; and HERC209 12m @ 2.9 g/t Au from 36m.

DEG said that a fence of RC holes 80m north east of existing RC at Brolga intersected 21m @ 1.0g/t Au from 50m in HERC147; while a fence of three RC holes 80m southwest of previous RC at Brolga intersected 9m @ 2.2g/t Au from 59m, and 3m @ 10g/t Au from 152m in HERC153.

The company said that the RC drilling targeting near surface mineralisation is underway in the west of Aquila.

Metallurgical diamond drilling

The company announced that specific diamond drilling has been conducted at Hemi to provide samples for metallurgical variability and optimisation testwork.

DEG said that the metallurgical drill holes into Brolga were located to provide samples from across the zone, so that it allows metallurgical testing to assess the spatial variability of mineralisation.

Significant results include HEDD004: 62.0m @ 2.2g/t Au from 47.0m, 19.8m @ 1.8g/t Au from 117.0m and 13.0m @ 2.1g/t Au from 151m and 15.8m @ 0.9 g/t Au from 170.2m;  HEDD005: 12.1m @ 1.0g/t Au from 43.8m, 1.6m @ 1.9g/t Au from 69.7m and, 4.3m @ 2.8g/t Au from 96.0m and 3.2m @ 8.0g/t Au from 106.3m; HEDD006: 4.4m @ 1.2g/t Au from 88.7m, 0.9m@ 3.3g/t Au from 110.1m, 4.0m @ 0.8g/t Au from 129.0m, and 23.2m @ 2.8g/t Au from 139.9m; and HEDD008: 36m @ 1.2g/t Au from 74m, 13m @ 1.8g/t Au from 157m, 18.4m @ 0.9g/t Au from 220m, and 10.35m @ 2.1g/t Au from 333m.

The company said that a representative composite sample will be formed using samples from all of the metallurgy holes for testing. DEG said that samples are being separately collected from Aquila for testwork.

Updates and next steps

De Grey reported that follow up aircore drilling will be undertaken to test for strike extensions to mineralisation.

The company said that programs of follow up RC and diamond drilling aimed at extending resources at depth and laterally are underway.

Management comments

De Grey Managing Director Glenn Jardine said: “We continue to test for extensions to known mineralisation around Hemi using aircore and RC drilling.

Aircore drilling has intersected new mineralisation approximately 320 metres north east of Brolga. This is along the structural corridor heading toward Scooby. RC drilling has succeeded in identifying extensions to the north of Brolga, heading toward Aquila.

Specific diamond drilling has been conducted to provide samples for metallurgical variability and optimization test work. The assay results from metallurgical drilling will provide additional information on internal continuity of the gold mineralisation within Brolga.

The rig combination at Hemi is allowing us to locate near surface extensions with aircore drilling, delineate and extend known mineralisation with RC and then look for depth extensions with the diamond rigs. This combination is working successfully toward our strategic goal of making Hemi a Tier 1 scale deposit and finding additional upside nearby.”