Respirable Dust and Respirable Silica Exposure in Ontario Gold Mines

Abstract

A comprehensive survey of respirable dust and respirable silica in Ontario gold mines was conducted by the Ontario Ministry of Labor during 1978–1979. The aim was to assess the feasibility of introducing gravimetric sampling to replace the assessment method which used konimeters, a device which gave results in terms of number of particles per cubic centimeter (ppcc) of air. The study involved both laboratory and field assessments. The field assessment involved measurement of airborne respirable dust and respirable silica at all eight operating gold mines of the time. This article describes the details of the field assessment. A total of 288 long-term (7–8 hr) personal respirable dust air samples were collected from seven occupational categories in eight gold mines. The respirable silica (α-quartz) was determined by x-ray diffraction method. The results show that during 1978–1979, the industry wide mean respirable dust was about 1 mg/m³, and the mean respirable silica was 0.08 mg/m^3.The mean% silica in respirable dust was 7.5%. The data set would be useful in future epidemiological and health studies, as well as in assessment of workers’ compensation claims for occupational diseases such as silicosis, chronic obstructive pulmonary disease (COPD), and autoimmune diseases such as renal disease and rheumatoid arthritis.

Keywords:

• respirable dust
• respirable silica (α-quartz)
• gold mines
• konimeter counts
• gravimetric concentrations
• silicosis

ACKNOWLEDGMENT

The authors thank all the staff of the Ontario Ministry of Labour who were involved in the study. They also express their appreciation to all the workers and management personnel who participated in and helped with the study.