Alderan Resources Limited (ASX: AL8) has revealed it will focus future drilling on the Drum Gold Mine and the Mizpah gold prospect within its Detroit Project, located in the Drum Mountains region of western Utah, USA.
Drum and Mizpah are distal disseminated gold deposits which lie only 2km apart to the southeast of the Basin porphyry.
Managing Director, Scott Caithness, said the decision to focus on Drum and Mizpah follows receipt of assays for hole 3DD21-001 and expedited sections of holes 6DD21-004 and 6DD21-005 which returned low gold grades.
“Based on results to date, Alderan’s Detroit drilling programme has been successful in focusing our future exploration effort. Drum and Mizpah are both clear standout prospects with higher gold grades and potential for both oxide and primary gold deposits,” Mr Caithness said.
“Alderan’s modelling of 1980s drill data at Drum and Mizpah indicates combined potential for approximately 82,000 – 167,000 ounces of dominantly oxide gold mineralisation based solely on these drill holes.
“There is additional upside potential as both deposits remain open and neither have been explored for primary gold mineralisation below the oxide.
“This primary potential is indicated at Mizpah by holes ending in assays up to 9.0g/t gold and at Drum by holes drilled 150m down dip of historically mined ore which intersected up to 15m grading 4.5g/t gold.”
Detroit Drilling Update
Alderan has received gold only assays for drillhole 3DD21-001 and results for the expedited sections in holes 6DD21-004 and 6DD21-005. These holes are part of Alderan’s 10-hole programme to test seven separate geochemical, geological and geophysical targets at Detroit.
Gold assays received to date are low order (<0.1g/t Au) for all of samples submitted; multi-element assays, including copper, are yet to be received.
Hole 3DD21-001
Alderan designed this hole, drilled to a depth of 332.4m, to test the high amplitude 80 millisecond Southern chargeability geophysical anomaly located in close proximity to the historical Charmed gold mine. The anomaly occurs at a favourable stratigraphic contact between shales and limestone and across a west dipping fault.
The hole intersected a largely unaltered sequence of grey limestones and calcareous siltstones and shales. The source of the chargeability anomaly is interpreted to be carbonaceous shales and pyrite intersected in the top half of the hole.
Alderan submitted 242 samples including standards for multi-element analysis and gold assay results received are all low grade with the highest assay being 0.08g/t over the interval from 279.5 – 280.8m (1.3m) downhole.
Hole 6DD21-004
Drill hole 6DD21-004 was drilled to a depth of 209.4m, testing the Northern Extension chargeability anomaly for a distal disseminated gold deposit in favourable host stratigraphy and in close proximity to the Copperhead Fault. The Northern Extension chargeability anomaly has a 3D inversion model strike length of 1.1km, width of 500m and depth extent of 500m at a >20 millisecond cutoff.
The east-southeast trending Copperhead Fault is interpreted to be one of the major mineralising structures at Detroit with Alderan rock samples collected at the historical Copperhead mine grading up to 3.1% copper and 9.1g/t gold.
The hole intersected a sequence of altered calcareous shales and siltstones interbedded with limestones and dolomites. The prospective Chisholm and Tatow units were both traversed with the Chisholm intersected over a downhole length of 61m having strongly developed iron oxide clays and local silicification. The Tatow consists of a 33m length of brecciated, carbonaceous and calcareous siltstone and shale with dark fine-grained sulphide flooded bands.
A 21m length (124.6 – 145.5m downhole) of sheared, carbonaceous and strongly altered Tatow containing >10% sulphides was sampled and submitted for expedited lab analysis2, however gold assays are low grade. The highest assay being 0.04g/t Au over the interval from 139.4 – 140.9m (1.5m) downhole.
Hole 6DD21-005
Drill hole 6DD21-005, testing the 3D inversion modelled 900m long dumbbell shaped Copperhead chargeability anomaly (>20 milliseconds cutoff) in targeted Tatow host stratigraphy near the Copperhead fault ended at a depth of 441.07m. It traversed a similar interbedded fine grained clastic sediment and carbonate sequence as hole 6DD21-004.
The prospective Tatow Formation is intersected over approximately 20m from 389m and consists of silicified, fractured and oxidised, calcareous siltstone with approximately 10% fine grained magnetite and sulphides. A total of 21 samples from a 31.8m interval (396.6 – 428.4m downhole) were submitted for expedited lab analysis with the highest gold assay being 0.07g/t over the interval from 404.5 – 406.1m (1.6m) downhole.
Assays for the remaining portions of the holes are yet to be received along with assays for holes 7DD21-002 & 003 and 6DD21-006.
Drum and Mizpah Background and Next Steps
Drum Gold Mine
Alderan secured an option over the Drum Gold Mine, one of the most productive and economically important sediment-hosted gold deposits in Utah, in late September 2021 as part of its strategy to consolidate the Detroit mining district.
Drum was discovered in 1982 with a drill intercept of 15m grading 8.5g/t gold and was mined from the adjacent East and West pits between 1984-89. Over its six-year mine life, it reportedly produced 125,000oz of gold from 3.17 million tonnes of oxide ore grading 1.22g/t gold. Towards the end of its life, a small underground operation was developed in the West Pit which produced mined grades of +4g/t gold.
Alderan’s review of historical drill hole data at Drum suggests exploration potential for approximately 1.2 – 1.5 million tonnes of remnant mineralisation at an approximate grade of 1.1 – 1.4g/t gold (approximately 42,000 – 67,000 ounces)5. This estimate of exploration potential quantity and grade is conceptual in nature, there has been insufficient exploration to estimate Mineral Resources and it is uncertain if further exploration will result in the estimation of a Mineral Resource.
The mineralisation remains open along strike to the south and down dip to the southwest where drill holes include YC-174 which intersected 15.2m grading 4.5g/t gold (including 6.1m at 10.3g/t Au) 150m from historical ore in
the West Pit. The ore horizon mined in the East Pit remains open down dip to the southwest and has not been drill tested below the West pit. Drum has both long and high-grade historical drill intercepts with hole DM-9 having a 70.1m intercept grading 1.0g/t gold and the highest grade individual assay over a 5ft (~1.5m) sample interval being 38.8g/t gold.
Alderan composite grab rock chip sampling along the outcropping walls of the East and West pits has focussed on altered target host rocks of the Tatow and Chisholm formations which were the prime ore horizons during historical mining and in visible structural zones interpreted to be potential hosts of high-grade mineralisation.
This sampling has verified the potential of Drum with the highest gold assay being 10.65g/t over a 2.8m sampling interval. Additional high-grade sample intervals include 1.7m grading 7.01g/t gold and 2.8m grading 5.86g/t gold. A total of 36 samples grade +0.5g/t gold with 22 of these grading +1.0g/t gold. An additional 17 samples grade +0.15g/t gold which is above the cutoff for oxide gold leach operations in neighbouring Nevada.
Alderan has already commenced drill site permitting so that drilling at Drum can commence in Q1, 2022 as part of its current Detroit drilling programme.
For further information please visit: https://alderanresources.com.au/
