From the 18thC. Greenwich Hospital leased the rights to mine for lead and other minerals to a number of companies. The most significant of these was the London Lead Company, but other smaller companies and partnerships also took on leases, with varying degrees of success. The London Lead Company's work led to Alston Moor becoming one of the main lead producing areas in the country by the mid-19th C, especially around Nenthead. The population of the area rose to a peak of around 5,000 in this period. By the 1860s, cheaper imports were making the local lead industry unprofitable, and by 1896 the leases had passed to the Vieille Montagne company, who worked the mines for zinc, which had earlier been of little commercial value.