Health Hazard Evaluation Report: HETA-88-022-1926: Summitville Consolidated Mining Company, Inc.; Del Norte, Colorado

Abstract

In response to a request from the Summitville Consolidated Mining Company, Inc. (SIC-1041), Del Norte, Colorado, an evaluation was made of cyanide (57125) exposures among heavy equipment operators working on a heap leaching pad at a surface gold mine. Several operators had experienced symptoms consistent with cyanide poisoning. This company was involved in gold and silver mining operations. Air samples for cyanide showed that the exposures for heavy equipment operators ranged from 0.004 to 0.02mg/m3. All results were below the NIOSH REL for cyanide. Area samples collected nearest the surface of the leach pad revealed concentrations of 0.09 and 0.06mg/m3 in samples collected in a low area where pools of the cyanide solution had accumulated. Ambient temperatures during the sampling were far colder than they had been during the time when the workers were taken ill. No health hazard from cyanide exposure could be documented at the time of the survey. The authors recommend: continued training for employees; that well trained medical personnel and cyanide emergency kits be available on site; monitoring operational factors; use of a continuous reading monitor in the bulldozer cab when contaminant concentrations may be high; equipping bulldozer cabs with emergency escape respirators; cautioning equipment operators not to leave their equipment cabs in the leach pad area without proper personal protective equipment; and good general housekeeping and personal hygiene practices