Project Highlight – Worker Exposure Monitoring in an Operational Mine

Project Description: Quality Environmental Services and Technologies (QUEST) was contracted to perform worker exposure monitoring in an operating commercial mine (project site) in the state of Colorado. QUEST performed worker exposure monitoring pursuant to the PH06-IV-1: Metal and Non-Metal Health Inspection Procedures found within the Mine Safety and Health Administration (MSHA) guidelines. From 2018 to 2021, QUEST conducted annual exposure monitoring and analysis at the project site. The data from the annual exposure monitoring was compared to MSHA standards for permissible exposure levels (PELs) of certain environmental constituents.

Sampling and Analysis: QUEST performed exposure monitoring at the project site of four environmental conditions; noise, respirable dust, airborne silica, and diesel particulate matter (DPM). The annual monitoring events utilized personal samples, worn by mining employees, and static position samples located at critical locations within the project site. The sample plan for each monitoring event comprised the use of a noise dosimeter, personal air pump, and a static air sampling apparatus. QUEST calculated the time-weighted-average (TWA) and the shift-weighted average (SWA) to determine worker exposure to these environmental conditions.

Conclusions: During these monitoring events, conducted annually between 2018 and 2021, QUEST identified certain exceedances in both noise exposure and respirable DPM exposure. As per QUEST’s findings and recommendations, subject employees were enrolled in a hearing conservation plan (HCP) and a respiratory protection plan. These recommendations were derived from comparing the collected exposure data to the MSHA guidelines, with the intention of reducing worker exposure of these environmental conditions to a level that is below the PEL. QUEST data and conclusions highlighted the difference in exposure of noise and DPM between miners and drivers at the project site. These findings were reflected in the recommendations for medical surveillance and personal protective equipment (PPE) for the various occupations and operations at the project site.