Mining and quarrying accounted for less than 1% of Kenya's GDP in 2000, having declined steadily since the end of World War II. Kenya was chiefly known for its production of fluorspar, limestone, gemstones, salt, soapstone, and soda ash. Cement was a leading industry and export commodity in 2002; production fell by half from 1996 to 2000 because of economic difficulties and decreasing export demand. A soda works at Magadi produced 246,000 tons in 2000, and Magadi Soda Ash Co. Ltd., the sole soda ash producer, extracted salt from the production of soda ash and was the largest salt producer. Lake Magadi had substantial resources of salt, trona (12.6 million tons), and soda ash (7 million tons). National output of crude salt was 44,900 tons in 2000, 21,742 in 1998, 6,280 in 1997, and 41,000 in 1996. Fluorspar (acid-grade) production, in the Keiro Valley, was 90,000 tons; exports increased to 83,658 tons at a value of $7.5 million in 1999, from 56,202 tons at a value of $4.7 million in 1995. In 2000, 690,000 tons of limestone was produced for cement, and 31,500 tons was produced for dimension stone. A limestone deposit near Bamburi and Mombasa had resources of 50 million tons, a travertine resource from the Umani Crater had 35–60 million tons, and marble resources at Mutini totaled 23 million tons.
In 2000, Kenya also produced secondary aluminum, anhydrite, barite, natural carbon dioxide gas, hydraulic cement, diatomite (near Gilgil, in the Rift Valley), feldspar, precious and semiprecious gemstones (amethyst, aquamarine, Iolite cordierite, green garnet, ruby, sapphire, and tourmaline), gold, gypsum, kaolin (total resources, from the Nyeri district, of 15–20 million tons), refined secondary lead, lime, petroleum refinery products, crude steel, coral, granite, marble, industrial sand (glass), shale, sulfuric acid, and vermiculite. The country also may have produced brick clays, coal, gravel, iron ore, kyanite, meerschaum, mica, murram (laterite), crushed rock, construction sand, and silica sand (from Kaloleni). Kenya's only lead mine stopped production in 1996. There were several gold deposits in the country—the Migori deposit contained 1.6 million tons at a grade of 4.3 grams per ton of gold. There were four substantial deposits of mineral sands in southeastern Kenya that contained ilmenite, rutile, titanium dioxide, and zircon—the combined resources of the Kilifi, Mambrui, Vipingo, and Kwale deposits were 3,100 million tons. Tiomin Resources Inc. was to exploit the mines sequentially, starting in 2003 at Kwale, because of its higher grades of economically recoverable minerals, and expected an annual output during the first six years of 300,000 tons of ilmenite, 75,000 tons of rutile, and 37,000 tons of zircon.