Walk-through survey report: control technology for mine assay laboratories at Pinson Mine, Winnemucca, Nevada, report no. CT-198-11a.
A study was made to evaluate control measures used in the mine assay laboratory at the Pinson Mine (SIC-8734), Winnemucca, Nevada. Pinson Mine was a gold and silver mining operation employing 110 persons. Ten of these work in the assay laboratory operation covering two shifts. The assay laboratory performed about 10,000 determinations each month, of which 2,500 to 3,000 were fire assay analyses. Workers were potentially exposed to lead (7439921), crystalline silica (14808607), respirable dust, mercury (7439976), and arsenic (7440382). Engineering methods used to control exposures consisted of material substitution, process and equipment modification, isolation and automation, and local and general ventilation. The Mine employed local exhaust ventilation and partial enclosures in the sample preparation area, flux mixing and fire assay areas. HEPA filtered half mask respirators were also worn during hazardous tasks. The greatest potential for exposure was in the sample preparation area, during litharge mixing, and in the fire assay room. Because of the apparent effectiveness of the control methods used at this site, the authors recommend the inclusion of this site for an in depth evaluation.