The most productive mine in the orefield, initially operated by the Beaumonts and later by the Weardale Lead Co., transitioned to fluorspar extraction in the 1940s. Reopening efforts were undertaken by the British Steel Corporation in 1969-70, rechristening it as the Beaumont Mine. However, the anticipated reserves of fluorspar were not discovered. By 1983, despite all equipment remaining intact, pumping operations ceased, and the mine became inactive.

Despite the commercial setback, the British Steel operation yielded some significant specimen finds. Particularly noteworthy were the pale lavender, twinned fluorites discovered circa 1970 in the remnants of flats along the Diana Vein, often associated with sphalerite and siderite.

The haulage engine house and hoppers remain as well as the (gated) mine entrance. There is also a row of miners cottages from the lead mining days.

As a lead mine
1877-1882 W.B. Beaumont
1883-1896 W.B. Lead Mines Co. Ltd

As a Floruite mine
1973-1979 British Steel Corporation
1980 British Steel Corporation, Ore Mining Branch
1983 Weardale mining and processing (unsure if they ever worked the mine)

The mine yard itself is not a public car park, however there is no access to the remaining mine infrastructure.