Cornish Metals (AIM:TIN), the AIM-listed developer of the South Crofty tin project in Cornwall, reported final assay results from its 2026 surface drilling programme at Roskear on Thursday.
The results confirm known tin lodes continue beyond the western limit of the current Mineral Resource Estimate, matching the company's geological model, while the second hole also uncovered a new high-grade tungsten zone and copper mineralisation not previously modelled.
Drillhole SDD26_002, drilled to 1,131 metres, returned multiple tin intersections including 1.51m at 1.46% tin (with 0.33m at 5.71% tin) at Roskear South, and 1.39m at 0.54% tin at Roskear B.
The hole also discovered a new tungsten zone returning 8.58m at 1.41% tungsten, including a standout 0.52m interval grading 15.15% tungsten, alongside high-grade copper intercepts of 0.62m at 6.59% copper and 0.58m at 1.85% copper with 14.20% zinc.
Roskear B was intersected approximately 91m west of the SDD26_001A intercept and 290m west of the company's metallurgical drillhole DD22_001, extending the confirmed footprint of mineralisation westward.
South Crofty is Cornish Metals' wholly owned, permitted underground tin project, where the company is progressing dewatering, shaft refurbishment and process plant engineering toward a final investment decision.
The Roskear West programme, comprising two holes totalling 2,330 metres, was the first drilling to test the company's near-mine Exploration Target identified in November 2024; results from the first hole, SDD26_001A, were reported on 9 July and had already shown tin intercepts outside the current resource envelope, including two previously unrecorded lodes.
"This is the first drilling programme to test our near-mine Exploration Target, and the results of SDD26_002 have demonstrated what we hoped," said Lauren Beverage, Chief Geologist of South Crofty.
"The new high-grade tungsten zone was not what we were drilling for, but is a welcome addition. Grades of this scale are not often seen in tungsten exploration, and they come at a time when tungsten has become a strategically significant critical mineral in the Western world," she said.
Tin remains the focus of South Crofty's production guidance, and tungsten does not currently form part of the resource estimate, but the company said the tungsten and copper results will be assessed as part of its wider exploration work.
Cornish Metals noted that tungsten concentrate was historically produced at South Crofty before processing moved to Wheal Jane in the late 1980s, and that provision has been made in the current plant design layout for potential future tungsten concentrate production using wet high-intensity magnetic separation equipment.
The company said tungsten is designated a critical mineral by the UK, EU and US, with China accounting for approximately 82% of global mined production in 2024 and having introduced export controls on tungsten-related products in February 2025.
Mineralisation was intersected throughout the granite section of SDD26_002 and remains open further to the west, with the company saying it will report any material developments from further evaluation of the exploration data.