Dart Mining (ASX:DTM) reports further ‘encouraging’ assay results from deep diamond drilling of geophysical targets completed this year at its 100% owned Granite Flat Copper-Gold Project in Victoria.
The company reports the assays demonstrate broad intervals of gold mineralisation, coincident with intervals of copper, silver, and molybdenum, which further emphasises significant bulk tonnage potential at the project.
Dart notes the assays returned ‘exceptionally long’ intersections of ‘low-grade’ gold with intervals of copper and molybdenum mineralisation.
The drilling program comprised of more than 1,002m across 3 holes which were primarily designed to test strong Induced Polarisation (IP) chargeability anomalies and were interpreted to possibly represent stronger zones of sulphide development.
Dart reports it will continue advancing the project with the next stage of drilling, targeting both the recently announced geochemical anomalies and the IP resistivity anomalies.
Assay highlights include:
- 113m @ 0.24g/t Au, 0.11% Cu and 0.75g/t Ag from 28m (EMDHH006), including 47m @ 0.33g/t Au, 0.16% Cu and 1g/t Ag.
- 165m @ 92ppm Mo from 151m, including 25m @ 330ppm Mo (EMDDH006).
- 409m 0.11g/t Au and 0.05% Cu from 23m (EMDDH006 entire hole, no cut-off).
- 42m @ 0.26g/t Au from 5m (EMDDH007), including 5m @ 1.12g/t Au, 0.6g/t Ag and 0.12% Cu.
- 143m @ 0.18g/t Au from 12m, including 25m 0.49g/t Au (EMDDH008).
- 291m @ 0.11g/t Au from 12m (EMDDH008 entire hole, no cut-off).
Additional geophysical targets await drill testing.
Dart Mining Chairman, James Chirnside said the assay results were ‘encouraging’.
“These encouraging drill results demonstrate that the company’s identified geophysical targets are associated with long intercepts of gold, copper, and silver mineralisation.
“These encouraging drill results demonstrate that the company’s identified geophysical targets are associated with long intercepts of gold, copper, and silver mineralisation”
This further underscores the significant bulk tonnage potential of Dart’s Granite Flat Copper-Gold project.”
Hole EMDDH006 was designed to target a substantial IP geophysical anomaly identified in late 2021.
At 432.6m depth, EMDDH006 represents the deepest hole to date in the Granite Flat project.
Throughout the length of the this hole, several intervals of potassic-and phyllic-altered quartz-feldspar porphyry and monzodiorite were identified, which are broadly associated with low grade copper-gold and molybdenum mineralisation.
The copper and molybdenum grade distribution in EMDDH006 displays a notable correspondence with the IP anomaly targeted, whereby gold mineralisation is associated with a low chargeability zone immediately above the high chargeability anomaly targeted.
Molybdenum mineralisation primarily follows the outer portion of the high chargeability anomaly, and all copper, molybdenum and gold mineralisation diminished towards the centre of the high chargeability anomaly.
EMDDH007 targeted a second ‘significant’ IP anomaly 1.3km away on the southern side of the Granite Flat project, and was drilled to a depth of 267.32m.
Hole EMDDH007 encountered narrower zones of gold, silver, and copper mineralisation, in part associated with narrow structures and basaltic dykes carrying disseminated pyrite and chalcopyrite, with semi-massive sulphide mineralisation near the margins.
Diamond hole EMDDH008 was drilled to a depth of 303m and targeted a sheeted vein system situated above a zone of elevated resistivity.
Whist not a strong low chargeability anomaly, the assay results from EMDDH008 display a similar pattern to the previous two holes, whereby zones of diminished chargeability are associated with long intercepts of ‘low-grade’ gold mineralisation.
These results indicate that significant intercepts of long, ‘low-grade’ gold mineralisation appears to be more closely associated with areas of elevated resistivity.
Dart’s preliminary interpretation is that zones of moderate to strong resistivity may reflect areas of stronger silification favourable to gold mineralisation and potentially to stronger chalcopyrite mineralisation.
As a consequence of this interpretation, Dart intends to test the strong resistivity anomalies located between the strong chargeability anomalies.
The gold results from the three diamond holes are ‘very encouraging’, demonstrating ‘strong, low-grade’ gold mineralisation over long intervals in holes separated by up to 1.5km.
This further demonstrates that the mineralising system at Granite Flat is of ‘significant’ size, corroborated by the exceptional soil results as reported in August.
The Granite Flat project is located 9km southeast of Mitta Mitta township and is accessed by the Omeo Highway.
Historically the prospect was mined at several small production centres between 1856 and 1918, following an initial discovery identified by tracing the source of alluvial gold in the Mitta River upstream.
Previously explorers have targeted the area with geophysical surveys, rock chip, soil and stream sediment sampling, and drilling and trenching.
Historic soil grids have established several large, ‘strong’ Cu-Au anomalies that have seen variable drilling efforts across the prospect.
In total, 18 costeans, 52 RC, and 19 diamond drillholes have been completed by previous explorers between 1986 and 1997.
The broad intersections of ‘low-grade’ Cu-Au mineralisation returned in historic drilling at Dart’s recent 42 hole RAB drilling program are hosted within potassic, chlorite and epidote-altered granodiorite, further confirming the potential for porphyry-style mineralisation.
Mineralised zones at Granite Flat are hosted within the Banimboola Quartz Monzodiorite (BQM).
The BQM has been broadly identified as hosting a porphyry style of Cu-Au mineralisation associated with I-type granitoid and sulphide veins, with alteration varying from silicic to argillic to propylitic, with moderate to high background copper.
Monzonite intrusive bodies are often the host of porphyry systems in the Lachlan Fold Belt.
Additionally, the Granite Flat prospect lies adjacent to the Gilmore Suture, a significant crustal-scale structure that is associated with the emplacement of several porphyry Cu-Au systems across the border in New South Wales.
Whilst still in the early stages of exploration, Dart Mining geologists believe that many of the geological characteristics and mineralised features of the Granite Flat prospect correspond with key elements of the porphyry exploration model.
Dart Mining’s objective is in exploring, evaluating and developing several historic goldfields, as well as validating a new porphyry province in Northeast Victoria.
The area is prospective for precious, base, battery and other strategic metals.
These include lithium, gold, silver, copper, molybdenum, zinc, tungsten, tin, tantalum and other important minerals.
Dart mining has built a strategically important gold exploration footprint in the Central and Northeast regions of Victoria, where historic surface and alluvial gold mining proves the existence of a significant regional gold endowment.
Images: Dart Mining Ltd
