Brenton Symon’s 1865 map identifies the Gwter Siani Vein and the Nant-y-Cwm Mawr Vein as running in an east-west direction. Along these veins, old mining shafts are positioned near the road leading up from Minera, just north of the Wynnstay sett. Several of these shafts remain identifiable today, with varying degrees of preservation. At SJ 2480 4980, a single shaft is present, featuring a damaged whim circle with an outer wall. Nearby, at SJ24954980, an old shaft is accompanied by spoil heaps, while at SJ 2470 4995, the remains of a collapsed shaft can be seen.

Further along, at SJ 2445 4990, a capped shaft has been fitted with ladder access for use by a caving club, with a leat running between the shaft and its spoil heap. Another capped shaft at SJ 2440 4995 includes an access trap door, while at SJ 2445 4980, the remains of a shaft and spoil heap are still visible.

Additionally, the Gomerian Level was constructed to unwater the Pool Park and South Minera Mines. This drainage level was driven from a point west of the Cae-llwyd reservoir at SJ 2700 4780, potentially originating from a shaft mound at SJ 2650 4780. It extended in a northwesterly direction, closely following the path of the South Minera Vein.