The largest mine in the Lake District worked on a single vein. This operation yielded over 2 million tonnes of lead ore and 2,000,000 oz of silver through nearly continuous extraction spanning two centuries until its closure in 1962 due to ore exhaustion. While specimens from this mine occasionally appear on the market, they are not abundant and primarily consist of primary minerals. Notably, specimens include attractive clusters of galena and calcite crystals, as well as small yet exquisite galena and chalcopyrite crystals atop micro-crystalline quartz, collected by Sir Arthur Russell from the 150-foot level. Calcite occurs in various habits, including scalenohedral and nail-head forms, with an exceptional example of the latter housed in the Keswick Museum. Additionally, baryte was found in coxscomb groups in the upper levels, while cerussite, witherite, and pyrite have also been reported.

• 1859-1869 John Jameson & Co.
• 1870-1874 John Jameson
• 1875-1878 John Jameson, Wm Whitwell, R.B. Smith,
• 1879-1906 Greenside Mining Co.
• 1914-1935 Greenside Mining Co. Ltd
• 1936-1962 Basinghall Mining Syndicate