Respirable dust exposure in underground gold miners at Obuasi in Ghana

Mechanised large-scale mining by European companies which began in the Gold Coast (now Ghana) as early as 1877 presently employs approximately 20,000 people. The Obuasi gold mine is one of the world's oldest and richest goldmines producing about eighty percent of Ghana's gold output. The study was conducted to quantify personal exposure to respirable dust and silica for different underground mining occupations in the Obuasi mine. Personal respirable dust samples were taken from a stratified sample of 125 (10%) of the 1229 underground miners available for the study. All filter samples were analysed gravimetrically and 1 in 10 filters analysed for their silica content. The mean shift/daily concentration of the underground respirable dust was 0.83 mg/m3 (SD ± 0.55) and a range of 0.07 to 2.86 mg/m3 over a mean sampling time of 6 hours. The concentration of respirable silica ranged from 0.01 to 0.12 mg/m3; mean 0.06 mg/m3. The mean silica content of the respirable dust was 9.93%. The present study shows a low personal respirable dust exposure levels as well as silica content in the Obuasi gold mines in Ghana. Keywords: respirable dust, crystalline silica, mining, personal air measurements Journal of Science and Technology Vol. 26(1) 2006: 14-21