American West geophysics turn up new Canadian copper storm

American West Metals has delivered three holes intersecting between 30.5m and 47.2m of visible copper sulphides after a reverse-circulation (RC) drilling campaign at its Storm copper project on Somerset Island in Canada’s Nunavut territory.

The company says the second hole of the program revealed a visible copper sulphide run of 36.5m dominated by chalcocite – an important copper ore mineral – between 79.3m and 115.8m down-hole, just north of the Cyclone deposit.

The company is hailing the outcome as an “immediate success” for the onset of its 2024 drilling program, viewing it as validation of its moving-loop electromagnetic (MLEM) geophysical techniques in the advanced reconnaissance stage. It says it shows a close correlation between MLEM and the drill program’s latest run of thick copper intercepts, pointing to the project’s potential to rapidly convert targets to resources.

The drilling program consisted of four initial holes, comprising two holes put in near the company’s Cyclone deposit and two holes near The Gap on the southern graben margin.

American West Metals managing director David O'Neill said: “The exploration drilling has had immediate success and has clearly demonstrated that the southern graben area can host multiple high-grade copper deposits. This vast fault network remains largely untested, highlighting the exceptional exploration upside and resource growth potential of this area.“

The 36.5m visible copper sulphide came from the campaign’s second hole, which was drilled to a downhole depth of 140.2m. It targeted a MLEM anomaly pointing to a possible northward continuity of Cyclone’s resource and a previous step-back hole that jagged 7.6m going 1 per cent copper from 105.2m downhole.

American West plunged a third drillhole into its The Gap area, midway between its small Cirrus prospect and the high-grade Thunder deposit. The objective was to follow up a strong conductor, picked up by the MLEM survey, which extends through an area of about 300m by 200m.

The conductor lies within a much larger zone of moderately conductive EM, which the company believes could indicate a greater extent of copper mineralisation at The Gap. The entire 149.4m length of the hole proved to be variably mineralised with a combined total of 47.2m of breccia and vein-style copper mineralisation, including a strongly sulphide-mineralised breccia interval about 10m thick from 39.6m downhole.

Management says the breccia/vein zone – characterised by the valuable copper ore minerals chalcocite, bornite and chalcopyrite – is visibly similar to that of a previous intercept nearby that nailed up to 4.4 per cent copper. It says the intercept also resembles the style noted at its Thunder prospect, 1.2km to the east, where a previous hole intersected 48.6m running 3 per cent copper.

The fourth hole was put in to 199.6m downhole depth beneath the third hole and across its section in a bid to better define the shape of the body intercepted in the third hole and its orientation. The hole succeeded in its objective, showing the body to be almost flat-lying, which could imply potential for horizontal extension.

The program demonstrated the potential for a possible northwards extension at Cyclone, which contains a JORC mineral resource estimate of 12.1 million tonnes at 1.2 per cent copper and 3.8 grams per tonne silver. It has also shown extension potential at The Gap, suggesting the 4km-long string of targets extending from Cirrus in the north-west and on to Corona, Lightning Ridge and Chinook in the south-east along the southern graben margin could lead to considerable resource growth.

The first hole drilled in the program was put in 500m north of Cyclone but showed little of interest. The company says it will revisit the location as it believes the weak fixed-loop electromagnetic (FLEM) signature might indicate a deeper target.

Management says the first phase of its MLEM survey has been completed in the Storm area and has successfully defined more than 10 new high-priority drill targets. Phase two surveying is now underway but has been rejigged to evaluate greater depths below 250m and underneath known targets using a 400m-by-400m loop.

The deeper targets include those where previous drilling of five deep diamond holes intersected a prospective copper horizon spanning more than 5 square kilometres at  about 270m to 300m vertical depth where grades up to 2.7 per cent copper occur in a sedimentary system and look like analogues of those in the southern African Copper Belt deposits.

Other MLEM surveys are planned to kick off in American West’s summer exploration program to assess the underexplored regional Tornado, Blizzard and Tempest areas. The company says its ongoing RC drilling at Storm will continue to test the burgeoning number of geophysical and resource expansion targets, while it will also continue its deeper phase-two MLEM in the immediate Storm area before moving on to the Tornado and Blizzard copper prospects.

A second RC drill rig is now onsite and some 20,000m of both RC and diamond drilling is planned for the coming weeks. Other preparations are underway for a broad range of environmental monitoring and survey activities through 2024, while studies on potential ore beneficiation methods are progressing on a variety of ores from the Cyclone and Chinook Deposits.

At the current discovery rate, American West’s MLEM geophysics will provide more targets in the short term than it can keep up with – but that sort of pipeline is one many explorers would envy. Now all the company needs is for the assays from its recent thick drill intercepts to come home and put the final tick of approval on the methodology.

Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au