Cornish Metals reported an unexpectedly high-grade intersection of 2.19% tin more than 100 metres below any historic mining at South Crofty mine in Cornwall.
Cornish Metals said the results reflected the mine’s potential and the possible discovery of “economic structures” in areas of the mine not previously considered.
The company contrasted the findings with the Renison Bell underground tin mine in Tasmania which mined an average grade of 1.32% tin in 2019.
The results are the second set posted by the company which has so far intersected three lodes in its diamond drilling programme.
The first results, posted six days ago, also revealed high-grade results. (bit.ly/3myPWxA)
| Hole ID | Lode Name | From(m) | To(m) | Width(m) | True Width (m) | Grade(Sn %) | Grade(Cu %) | Sn Eq %* |
| SDD20-001 | Tincroft South | 376.55 | 378.77 | 2.22 | 1.15 | 0.77 | 2.69 | 1.73 |
| (including) | 378.04 | 378.77 | 0.73 | 0.38 | 1.58 | 5.16 | 3.43 | |
| Tincroft | 470.35 | 472.52 | 2.17 | 1.66 | 1.34 | |||
| (including) | 471.79 | 472.52 | 0.73 | 0.56 | 2.50 | |||
| Intermediate | 620.60 | 623.26 | 2.66 | 1.85 | 2.19 |
Cornish Metals has tested multiple tin-bearing, vein-like lodes in the central section of South Crofty.
Today’s results are from an intercept which is a ‘step out’ from the intermediate lode, not included in the current resource, and is 110 metres below any historic mining on this lode.
Additional lode structures with visible tin mineralisation have been intersected deeper in hole SDD20-001 and the company is awaiting the assays.
“The intermediate lode structure was predicted by our geological team to be in this area but such a high-grade intersection so far beneath the old mine workings was not anticipated,” said Cornish Metals chief executive Richard Williams.
“It does reinforce the exploration potential at South Crofty and our ability to find economic structures within areas of the mine that have been previously overlooked.”
The 2,000-metre diamond drill programme began in June 2020 and is testing drill targets beneath mineralised veins or lodes that were mined until South Crofty mine closed in 1998.
Cornish Metals will also test the suitability of directional drilling combined with ‘wedges’ to produce multiple intersections of vein structures from a single surface or underground drill hole.
The initial programme comprises up to 2,000 metres of diamond core drilling from a single surface parent hole and up to three daughter holes that will be wedged-off the parent hole.
In addition to the parent hole, the first daughter hole has been completed, and a second daughter hole is currently being drilled.