I mad these notes on a visit in 1998:
There were in fact two mines worked here (Fedw and West Fedw), situated at Tylwch , south of Llanidloes at NGR SN975793. Most of the mine workings here are on a tributary of the Afon Dulas, with one outlying adit draining direct into the Afon Dulas. At the upper reach of the tributary there is an open level, which is holding back water, but not draining (the land owner believes this to be the water supply to Plas Tylwch). The tributary then passes under the B4518 to a mire (the remains of a holding pond) past extensive spoil heaps, filled shafts and the remains of the dressing floor ( traces of circular buddles visible) of Fedw mine, before joining the Afon Dulas. The adit on the bank of the Afon Dulas has a small spoil heap associated with it and is thought to be the deep adit for Fedw mine. The adit is dammed with vegetation/soil which allows the slow passage of waters, however an errosion feature suggests that it discharges at greater volume occasionally. North of West Fedw at is a level which was intended to be the deep adit for that mine. This level extends about 300 ft into the hill before coming to an end (bare rock rather than a fall), ie the work was abandoned before reaching the main workings.