Early mining in the area is likely to have been on the productive Westminster Vein, on which the Nant Mine worked the western end. Ellis's Shaft is capped with concrete at SJ19805768 and has an air vent inserted. The rectangular stone-lined Engine Shaft was capped by the 1978 shaft capping programme conducted by NKC Partnerships, and was reported as 2.1m x 3.4m. It lies to the west of the engine house. Shafts along the Westminster Vein lie to the west of the Nant Engine Shaft and can be located in woodland at SJ19255780, two adjacent shafts at SJ19305780, two adjacent shafts at SJ19355770; single shafts at SJ19505775 and SJ19605775. The most westerly working on the vein was apparently an old whim shaft to the north of Bryn-y-gloch. To the west, the Castell Engine Shaft at SJ20305750 remains unidentifiable in the vicinity of Castell Farm. It served to pump out New Shaft, which appears as a whim on the abandoned mine plan deposited CRO. The mine workings were drained by the Nant Adda Level, the portal of which is situated at SJ197577. The Grosvenor Caving Club have gained access to the underground workings and report that artefacts remain underground that might shed light on mining technology.