highly unlikely that anyone would have sunk a level close to or within a hot slag heap so Forge Level must pre-date the slag tip. The Balance Pit at Garn-yr-erw, shown by the above maps to have been sunk around 1838-39, was self-evidently a water-balance pit." In such pits, a tank full of water with empty trams or trucks on top of it was lowered down a shaft. The weight of the full tank and empty trucks was used to raise up an empty counter-balance tank which had full trams of coal on top of it. This was a simple and relatively common method of raising coal to the top of a pit. The method was also used for raising minerals or products from one height to another at many works in South Wales. Forge Pit, from documentary and archaeological evidence, was also a balance pit. The water-balance tanks still exist at the shaft bottom. The water taken down Forge Pit in the balance tanks was diverted away from the pit bottom through Forge Level which drained the water off into the river. Both the Balance Pit and Forge Pit were The Basic Layout of a Balance Pit