Mine building that appears to be too wide for a wheelpit but small for a crusher house, on the river bank. It is 7m N-S by 2.5m. The E side is built into the bank. The other sides retain some coursed masonry up to 0.7m high.
Mining at Castle Rock (NPRN 33991) is not precisely dated but associated structures appear to be C19.
D Bick, The Old Metal Mines of Mid Wales, Part 4, 1977, pp 14-15.
Recorded as part of RCAHMW Uplands Initiative Project. R Hayman, H&H, 10/11/2011.