Powys Metal Mines Survey

Nantiago

Geology
Ordovician Upper Van mudstones and grits. The main vein has a ENE-WSW strike. The N-S cross vein has calcite with galena and sphalerite.

Workings
A shaft and deep adit plus two other levels are visible. There are numerous small trials on the surrounding slopes.

Transport
Numerous tramways for running the ore from the adits to the dressing floors are visible.

Power
Leats running off from Nant Iago supplied water to three waterwheels and 2 Pelton wheels used for pumping, drawing and processing. The pumping wheel reached a maximum size of 60ft diameter. One cast iron Pelton wheel is intact and in situ on the dressing floor. A small gas engine was also formerly present on the dressing floor. The line of the high pressure pipe to the Pelton wheels can be seen as a scar on the hillside above.

Processing
In 1900 a new three-storey processing mill was erected which was driven by 2 Pelton wheels and included a stone breaker, rolls, trommels, and six 4 compartement jigs. This replaced a dressing floor about which we have little information. The 1900s mill is partially intact on the ground floor with much processing machinery either in situ or scattered around. Much woodwork survives. A collapsed trommel screen is still in place together with a Pelton wheel and part of a belt driven drive shaft. A small feeder cone is also present. It is possible that other machinery lies buried within the main structure.

Other features
Miners' barracks SN82558631, a store shed, mine office, and magazine are present but are poorly preserved. The cast-iron winding wheels from the shear legs and adjacent cage winder are present in the top of the shaft along with other debris. A cast-iron winding drum with gear wheel and rewound cable is partially buried in a spoil tip adjacent to the shaft SN82478638.

Comments
This site has two important features:

(1) The 1900 processing plant is the best preserved of its kind in the West Montgomeryshire orefield. It also has the highest concentration of in situ machinery and other dressing floor features on a mining site in this area.

(2) Other machinery parts related to the engine shaft winding gear survive in part. Again this is the most intact assemblage in West Montgomeryshire.