Alto Metals is planning to turn the ground at its Indomitable prospect into Swiss cheese in an aggressive hunt for gold extensions – particularly at depth – at the site near the Western Australian town of Sandstone.
The company says recent drilling results at its prospect have demonstrated the potential for a significant high-grade gold system. Results announced this month include 16m at 13.1 grams per tonne gold from 19m, 16m grading 7.2g/t from 65m and 25m at 7.5g/t from 41m, with each intersection having a higher-grade component up to 6m in width and up to 62.2g/t gold.
But while Alto says it remains firmly committed to its gold hunt, it now also believes the project may have a blue-sky lithium horizon. And with mining giant Rio Tinto recently farming into Everest Metals’ adjoining ground as part of its lithium-finding mission, the wider mineralisation possibility is not something to be ignored.
Alto has revealed it has already received third-party enquiries in respect to the lithium potential of its ground.
But in the meantime, the gold quest at Indomitable will continue as the company’s main mission through plans for deeper reverse-circulation (RC) drilling to test high-grade targets below its recent shallow high-grade intersections. Drilling to date at the deposit has been limited below 200m, offering considerable potential upside.
Alto recently released an independent mineral resource estimate for its wholly-owned Sandstone gold project, with an optimised and pit-constrained 17.6 million tonnes at 1.5g/t gold for 832,000 ounces within $2500-per-ounce pit-shells. More than 90 per cent of the resource is within 150m from surface and the unconstrained resource is 1.05 million ounces of gold.
However, after also reviewing lithium prospectivity on its Sandstone tenements, Alto has identified several pegmatite targets from high-resolution satellite imagery and multi-spectral analysis. Field inspection has identified outcropping pegmatites where several of the lithium targets were located.
The area is on the eastern flank of the Sandstone project area where Rio recently secured the adjoining ground, with a focus on lithium exploration.
Alto is now conducting field mapping and surface rock-chip sampling to further assess the lithium potential of its ground and is planning a soil geochemistry program. Management says no previous lithium exploration has been undertaken at the Sandstone project and considers its early work encouraging.
The company has engaged CSA Global and Terra Resources to support its lithium targeting work across its tenements.
Planning for the next phase of drilling at Indomitable is well underway to follow up on some of the exceptional results recently announced. Drilling is targeting the orientation of these interpreted high-grade structures within the fresh rock at depth. While our focus remains firmly on gold exploration at the Sandstone Project, our campaign-based exploration programs has allowed us to undertake low-cost regional exploration in parallel, targeting lithium. We are now moving to implement follow-up field verification and mapping programs to further define these targets. Alto Metals managing director Matthew Bowles
The company considers the Sandstone greenstone belt as being highly-prospective for lithium given lithium-caesium-tantalum pegmatites occur predominately in Archean greenstone belts of similar ilk to those at the project. Recent lithium exploration activity by Rio on ground adjoining Sandstone, in addition to ASX-listed Sensore farming into nearby ground held by Gateway Mining, has emphasised the lithium prospectivity of the region.
Remote sensing by Terra successfully identified many lithium pegmatite targets through the entire Sandstone project area, with a concentration in the greenstone granite contact on its eastern side. Targets were identified by shape, texture and colour and represent potential concentrations of lithium based on spectral signature characteristics.
Lithium is difficult to detect using satellite imagery and Terra reprocessed historical satellite data for correlation with known spodumene spectral bands.
Alto’s field inspection has confirmed outcropping pegmatites that appear to be parallel to the granite-greenstone contact, although much of the area is covered, limiting rock exposure at surface. The company will assess regional granite samples for the source-rock potential of lithium-rich pegmatites. The company also plans to assay selected historic drill samples for lithium and pathfinder elements.
Sandstone is contained within a 10km radius and continues to grow with each drilling program.
Indomitable is the current focus for extensional drilling. Its oxide gold footprint now extends to more than 3km and its resource tripled to 210,000 ounces in four deposits from surface with low stripping ratios in Alto’s April resource upgrade.
The deposit is open in every direction with the high-grade extensions in fresh rock at depth providing a juicy target for potentially-substantial resource increases. Indomitable sits in the 20km “Alpha Domain” priority target gold corridor that also contains the Vanguard and Havilah deposits. Vanguard has a 150,000-ounce resource at a head grade of 2g/t gold, while Havilah has 46,000 ounces of gold from surface.
Alto’s Lord Nelson deposit is open down-plunge and has a 263,000-ounce gold resource under its old open pit, which gives a low stripping ratio. Its Lord Henry deposit contains 90,000 ounces of gold and is just 3km from Lord Nelson, with resources also being under the old pit.
In recent drilling at its Musketeer deposit, the company extended the mineralisation along strike by 240m. Nine step-out holes drilled at its Duke of Windsor and Eclipse mines confirmed extensions to the historically-mined reefs, with results up to 3m at 5.1g/t gold from 87m, including 1m grading 12.3g/t gold at the latter.
Given the recent high-grade gold intersections combined with the limited drilling, Alto is bringing a focus on deeper probing to delineate high-grade gold mineralisation. And with the rigs getting ready to roll at Indomitable, its excitement is palpable.
If the company can do enough work to demonstrate lithium potential on its ground, it may just snag a big fish to do the heavy lifting on that exploration front. It would give shareholders a free ride while Alto’s flagship gold project keeps growing and pushing towards development.
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