Little evidence remains of the later large-scale mining operations, as much of the area was reclaimed. A large shaft, capped with concrete in 1954, remains on the village green at SJ 2090 7015. This shaft, the site of Lewis’s Shaft and the dressing plant of the Halkyn Mining Company in the early 20th century, is shown as a whim shaft on the OS 1st edition map.

The large-scale 20th-century workings of the Halkyn District United Mines around the Pen-y-bryn Shaft at SJ 2030 7070 have been lost to the quarry. Remaining evidence includes earth mounds and spoil heaps. The main shafts at SJ 2067 7017, SJ 2065 7010, and SJ 2062 6998 were made safe as part of a program in the 1970s.

The Deep Level Mine, like other mines in the area, was drained by the Halkyn Deep Level Tunnel, which began construction in 1818.

The extensive mining sett worked the Crockford or Deep Level Vein to the west of the Pant-y-gof Vein, with early mining activities taking place at Pantyffrith. The area was later affected by a land reclamation project in the early 1970s. Two commemorative stones in the vicinity of the reclaimed mine area acknowledge the Prince of Wales Award for the reclamation of derelict land, presented to the local residents of Halkyn and The Wimpey Asphalt Pant Quarry.

Smith (1921) records the principal shafts on the Pant-y-gof Vein as Trustees (near the Engine House), Pant-y-Gof Shaft (200 yards northeast of the Engine House), and Eaton’s Shaft, along with two levels: the Deep Level and another on Eyton’s Shaft. The mine was part of the Halkyn District United Mines Ltd. from 1928.