A review by Alderan Resources (ASX: AL8) of historic results from the recently-acquired Drum gold mine in North America has highlighted the potential for high-grade extensions to remnant mineralisation.
The mine is located in the southeast portion of Alderan’s flagship Detroit copper-gold project in the Drum Mountains region of western Utah.
It has a strong gold mineralised footprint which has received no modern exploration since mining ceased in 1989.
As part of its review, Alderan looked at historical data from 404 holes drilled around the Drum deposit during the 1980s to assess its potential to host an economic gold deposit.
The average hole depth was 49m and only 11 holes were drilled to over 100m (maximum hole depth 154m).
Alderan said the review outcome was consistent with the mine’s reported historical production of 125,000 ounces of gold from 3.17 million tonnes of oxide ore grading 1.22 grams per tonne and supported the potential for remnant gold mineralisation below the adjacent East and West open pits, plus down dip and along strike extensions to the main Drum deposit.
It highlighted that mineralisation in both pits remains open along strike to the south and down dip to the southwest and the mined mineralised horizon in the East Pit has not been drill tested below the West Pit.
A 3D model of gold distribution at Drum from the historical drilling has highlighted that significant gold intersections (grading more than 1.1g/t) sit immediately outside the historical pit boundaries to the southwest.
The model suggests the mine has exploration potential for between 1.2-1.5Mt of remnant mineralisation grading 1.1-1.4g/t gold for between 42,000-67,000oz.
The mineralisation remains open along strike to the south and down dip to the southwest where historic drilling returned an intersection of 15.2m at 4.5g/t gold (includes 6.1m at 10.3g/t), which is 75m from the West Pit boundary and 150m from historical ore.
The model highlighted the presence of two sub-parallel, southwest-northeast trending higher-grade zones on the northern and southern side of the pits. These zones parallel the sub-vertical King Tut Fault which trends along the pits’ south-eastern edge and is believed to be a key control on mineralisation.
Alderan’s review included historical assays from 5,425 samples analysed by fire and AAS (atomic absorption spectrophotometry) techniques. The highest individual assay grades 38.6/t gold and 24 holes ended in anomalous grades of more than 0.5g/t gold.
Samples were predominantly collected at 1.54m downhole intervals, with the exception of a small number of holes drilled outside the pit boundaries, which were sampled every 3.08m.
The company said its forward plan includes in-pit rock sampling, structural and geological mapping and a magnetic geophysical survey.
A drilling program is being planned for Drum in the new year pending exploration results and the receipt of drilling permits.
Prolific mining district
Located within Utah’s prolific Detroit mining district, the Detroit project contains numerous historical copper, gold and manganese mines.
The area has been previously explored for copper and gold by the likes of Anaconda Copper, Bear Creek Mining Company, Newmont Corporation and BHP Group (ASX: BHP) but none were able to build a significant contiguous land position to enable district-wide modern exploration.
Alderan has a consolidated exploration area at Detroit covering 25.5 square kilometres through a series of option agreements with tenement owners.
The Drum gold mine was discovered in 1982 with a drill intercept of 15m at 8.5g/t and was mined from the East and West pits for six years from 1984, during which time it reportedly produced 125,000oz of gold from 3.17Mt of oxide ore grading 1.22g/t.
Towards the end of its life, a small underground operation was developed in the West Pit which produced grades greater than 4g/t gold.
In September, Alderan secured an option to acquire unpatented lode mining claims at the Drum mine following an agreement between North Exploration LLC and Alderan’s US subsidiary Valyrian Resources Corp.