Mining Environmental Target Surveillance Investigation. Kyanite "Sillimanite" Group Minerals.
NIOSH 1981 Nov:21 pages
Potential health hazards of miner exposures to kyanite (1302767) dust were investigated. Potential toxicity of four minerals in the kyanite group was estimated on the basis of physical appearance and free silica (14808607) content. The four minerals of the group were andalusite (12183801), sillimanite (12141456), mullite (1302938), and kyanite. Bulk samples and breathing zone air samples were taken and analyzed by light microscopy and transmission electron microscopy. Quartz (14808607) was commonly found around kyanite deposits and cristobalite (14464461) was formed when the minerals were calcined. Free silica in respirable dust samples reached as high as 48 percent. Andalusite, kyanite, and sillimanite decomposed at about 1550 degrees-C to form mullite and cristobalite. Cristobalite was present in the minerals produced in two facilities. Breathing zone air samples of free silica exceeded NIOSH recommended standards in 8 of 17 samples, with respiratory protection worn by five of the eight workers. The author concludes that potential exposure to dusts containing free silica exists for about 175 kyanite ore miners.
NIOSH-Author; Mining-industry; Air-contamination; Dust-exposure; Safety-research; Sampling-equipment; Testing-equipment; Laboratory-testing;
1302-76-7; 14808-60-7; 12183-80-1; 12141-45-6; 1302-93-8; 14808-60-7; 14464-46-1;
NTIS Accession No.
Mining Surveillance Team, Environmental Investigations Branch, NIOSH, Cincinnati, Ohio, 21 pages, 16 references