On the West side of Trevellas Combe (historically spelled “Trevallas Combe”), at Wheal Butson Farm.

Dines gives details of a number of shafts and adits. Of these traces are still visible - all the shafts clwyd capped, and likely blocked adits evidenced by flows of water.

Likely mined Copper, and perhaps also Zinc and Lead.

Dines:

Also called East Tywarnhayle (A.M. R 4, dated 1851), this mine is on the west side of Trevallas Coombe, opposite Burrow and Butson Mine (6-in. Corn. 56 Ν.Ε.) and worked the same lode, here coursing E. 15° N. and underlying 32° S.

Engine Shaft, 500 yds. E. by S. of Hurlingbarrow farm, is vertical to the 20-fm. Level and on the underlie to the 50-fm. below adit (12 fms.). At 115 yds. W. of Engine Shaft is Way’s, vertical to below adit and on the underlie to the 20-fm., and at 50 yds. N.E. is Thomas’s, vertical to below adit and on the underlie to the 11-fm. A third shaft, unnamed on the plan (A.M. R 45, dated 1851 and similar to R 4), 210 yds. E. by N. of Engine Shaft, is vertical to 10 fms. below the 20-fm. Level; there are also five adit shafts.

Adit Level commences near the stream and extends to 100 fms. W. of Engine Shaft, a total of 260 fms. There is only a short drive at the 11fm. - Level from the bottom of Thomas’s Shaft. The 20-fm. Level is in two parts, one extending for 45 fms. E. and 55 fms. W. of Engine Shaft, and the other for 8 fms . E. and 40 fms. W. of the unnamed shaft; the 35-fm. Level opens up the lode for 45 fms. E. and 55 fms . W. of Engine Shaft, and the 50-fm. for 25 fms. E. and W. There are three very small stopes on Adit Level, one just west of Way’s Shaft and the others on either side of Engine Shaft, and a fourth below the 11-fm. Level. Two vertical N.-S. crosscourses intersect the lode, respectively at 40 fms. and 110 fms. E. of Engine Shaft.

A separate working is from an adit that commences close to the stream 340 yds. E. of Engine Shaft and at 105 fms. S. by W. of its entrance meets a shaft on a lode that is driven on for 10 fms. W. to a crosscourse (the eastern one of the main workings).

Now, as of 2024, conveniently adjacent to the Goonbell to Chiverton section of the St Agnes to Threemilestone Saints Trail.

The land on which the shafts lie, above Roskarros, is private, however the remains of the drainage adit lie on common land by Brook View Barn.