The historic mineral sector of Swaziland has essentially collapsed. The kingdom contained the world's oldest known mine site, the Lion Cavern, at the Ngwenya iron mine, on Bomvu Ridge, northwest of Mbabane. Carbon-14 dating estimated that mining—of hematite (libomvu) and specularite ochres, for cosmetic and ritual uses—took place at the site from 43,000– 41,000 BC until at least 23,000 BC ; the mine was closed in 1977. Mining's role in Swaziland's economy has been declining in recent years, and mining and quarrying accounted for 1.4% of GDP in FY 2000/01. A methane gas explosion caused Swaziland's only coal producer to close in 2001, asbestos mining ceased in 2000, diamond mining ceased in 1996, and mining of the once-major export iron ore stopped in the late 1970s (it reached 2.24 million tons in 1975).
In 2001, Swaziland produced 350,000 cu m of quarry stone products, and also produced brick clay, anthracite coal, pyrophyllite, and sand and gravel. Small-scale, unreported gold mining has taken place. The mining of chrysolite fiber asbestos, once the dominant source of mining revenue—employing 1,000 workers at Bulumbe, one of the world's largest asbestos mines— ceased because of declining reserves, environmental concerns, and weak markets. Mined since 1939, 27,693 tons of asbestos was produced in 1998. Mining of mainly industrial-quality diamonds was from a single kimberlite pipe at Dvokolwako, and was jointly operated by the Swazi Nation (distinct from the government) and a South African company; production was 70,000 carats in 1996. Although fewer than 1,000 Swazis were directly employed in the mining sector, 1,000 people processed timber from the country's extensive pine populations for mines in South Africa, and 10,000–15,000 Swazis were employed in South African mines. Their contributions to Swaziland's economy through wage repatriation have been diminished, though, by the collapse of the international gold market and layoffs in South Africa.