Plas Tan y Bwlch No description specified. 1-4 (4 Records) Documents The Experimental Hafting of Stone Mining Hammers (1990) Firesetting and Primitive Mining Experiments, Cwmystwyth, 1989 (1990) Firesetting experiments at Rhiw Goch, 1989 (1990) Firesetting Experiments on the Great Orme, 1989 (1990)