Document M496L3kpq2Jz3LkVdrmVN3G9V

PRODUCED BY FORD rpentlne hills of Thetford and Coleraine. By 1900 this area had ol:edy produced 150,000 tonnes of chryaotlle fiber; by 1980 nearly 40 111ion tonnes had been mined -- approximately 40 percent of the world's Jtal asbestos production to' that data. At present Quebec is the second ending producer of asbestos, approximately 1.4 million tonnes per nmm, and is led only by the Oral areas of Russia, where the annual prouetlon la approximately 2.4 million tonnes. The serpentlnltes associated with ophlolltes within the Oral Mounain belt of the Soviet Onion account for about 95 percent of the Russian -reduction, all of which is chrysotlle fiber. The two principal centers >f production in the Orals are the Oralssbest complex, 90 km northeast of Sverdlovsk, and near Dzhetygara, In the southern Orals. Other major Type I chrysotlle asbestos deposits are found In the ttallan Alps, the Troodos Mountains of Cyprus, and the Coalings area of California. The classic asbestos deposits of north Italy are located In the Susa, Lanzo, Aosta, and Val Malenco areas of the Alps. These are areas underlain by metamorphosed ultranaflc rocks of the alpine-type. At present the Balangero mine, located 30 km northwest of Turin In the T.anzo area, la the only operating asbestos mine In western Europe of any significance. The mine opened In 1916 and Its present production Is about 160,000 tonnes of chrysotlle fiber per year. The occurrence of asbestos on Cyprus may hove been known many cen turies ago, but significant production of chrysotlle fiber began only In the 1920's. Production is now about 40,000 tonnes per annum. The deposits are In the Mt. Troodos Ophlollte Complex, one of the best studied ophlollte sequences In the world. Sear Coolings, California, and located In the southern extension of the Di.iblo Range Is a eerpentlnite dome exposed to the surface In an area 19.2x6.4 km and extending In depth to perhaps 4.5 km. This serpentine dloplr consists of highly sheared serpentine minerals, which replaced the original ollvlne-orthopyroxene assemblage. The dlaplr probably formed by dicncmbcrment of on ophlollte pcrldotlte by tectonic forces, the sheared cflangc moving upwards dlnplrlcnlly during subsequent orogcnlc eventa (Coleman, 1977, 1980; Mumpton and Thompson, 1975). The chrysotlle asbes tos is mined by several companies at Coalings, but mining Is sporadic and production Is limited. Even though the ore runs up to 50 percent 798 8005 0060 chrysotlle (Quebec ore usually runs 3 to 6 percent), mining has lagged because of environmental controls and the shortness of the fibers (grades nos. 6 and 7). The reserves at Coalings are tremendous; per haps tens of millions of tonnes of sfjprt fiber are available near the surface, making Coalings a vast resource fpr a type of asbestos which will be useful to strengthen plastics, tiles, ete. Type II deposits of southern Africa Vhereas most of the chrysotlle mined in the two major asbestos producing countries, Canada and the U.S.S.R., Is from eerpentlnized ultranaflc rocks within ophlollte sequences, almost all of the southern African production comes from Archean ultramafle stratiform complexes. These are generally associated with the eneient greenstone belts on tho Rhodesian and Kaapvnal Cratons (Anhaeusser, 1976). Vlthln the African greenstone belt, and particularly In the Lower Ultramafle Unit, a number of layered differentiated ultramafle pods and sills are developed vblch contain chrysotlle fiber of economic Importance. While age, strati graphic, and genetle relationships of these Archean ultramaflcs are quite different from those of the ophlolltes, both contain perldotite assem blages, Including dunltea, which have altered to chrysotllc-hcarlng serpentlnlte. South Africa and Suaniland. Mere the two largest producers of chrysotlle asbestos are the Mssuli and Havelock mines, situated approxi mately 30 km southeast of Barberton, South Africa. The Havelock mine is situated just over the Transvaal border In Swaziland. These deposits are Included within the Svarthopple Formation, whleh straddles the Svazlland-Transvaal border. This formation Includes green and grey schists, banded chcrtn, and a number of serpentine pods or lenses positioned In the same stratigraphic horizon. The eerpentlnized nltramaflc Inclusions are considered to represent parts of a once continuous or nearly con tinuous differentiated sill emplaced peneeontemporaneously with the remaining Swartkopple roeka and conformable with the letter (Anhaeusser, 1976). The other active chryaotlle mines In South Africa occur In ultrnmaflc bodies similar to those In the ftsoull-Havclock area. Deposits located in Barberton Mountain Land of South Africa occur in the Stolzburg, Koedoe, Handsup-Mundt's Concession, Kaopaehoop, Kalkkloof, and 299