DANGEROUS DUST: Protecting Miners from Respirable Crystalline Silica

The mining industry is booming. Mining contributed $125 billion, or five percent of Canada’s total gross domestic product (GDP) in 2021. The industry employs 665,000 workers in Canada¹ and 566,000 in the US.²  These numbers are expected to rise exponentially as mining companies strive to meet the rising global demand for critical minerals and materials needed to power the clean energy transition and advanced manufacturing -- from zero emission vehicles (Li-ion batteries, permanent magnets and specialty alloys), wind turbines and hydrogen fuel cells, to information and communication technologies (including semi-conductors).

While mining is poised for unprecedented prominence, there remains the fact that it’s an inherently dangerous profession. For instance, tens of thousands of miners face occupational exposure to hazardous silica dust, also known as respirable crystalline silica. Silica dust can be generated in most mining activities, including cutting, sanding, drilling, crushing, grinding, sawing, scraping, jackhammering, excavating, and hauling rock, gravel, and sand. These tiny silica dust particles are at least one hundred times smaller than a grain of sand and breathing them in can contribute to silicosis (long-term stiffening of the lungs). Scarring and inflammation can occur, reducing the lungs’ ability to take in oxygen. This occupational hazard also contributes to workers’ risk of developing other respiratory diseases (e.g., emphysema), progressive massive fibrosis, kidney disease and lung cancer. These illnesses are sometimes chronic and irreversible, potentially leading to disability or fatality.³

SAFETY MEASURES

There are a variety of control measures available to help mitigate the risk of silica dust exposure at the mining worksite. When respiratory hazards are present, it’s best to apply the hierarchy of controls, which include levels of actions to reduce or remove hazards. For mining, these are usually most relevant:

·       Engineering controls, including wet and dry methods to reduce dust exposure

·       Administrative controls, including training, supervision, and medical surveillance and monitoring, safety plans, and regular site inspections and exposure assessments

·       Personal Protective Equipment (PPE), notably proper respiratory protection

RESPIRATORY PPE

Although PPE is considered a last line of defense in the hierarchy of controls, respiratory PPE is critical for mine workers and it’s required by the Mine Safety and Health Administration.³  There are a number of different types of respirators suitable for above ground/open pit and below ground mining, including half masks, full facepieces and disposable respirators. Honeywell offers PPE solutions that can contribute to compliance, durability, comfort, and enhanced work productivity. The 7700 Series half mask is highly regarded. It features a wide sealing area. The 7600 full facepiece features a  Premium grade silicone sealing area, plus a lens offering 200 degrees of vision. The DC300 N95 disposable mask is an excellent choice for mining drivers. It’s humidity- and moisture-resistant with a rigid outer shell to help prevent the mask from collapsing in humid environments. The molded nose bridge also enhances a proper fit and secure seal.

MSHA SILICA SAFETY STANDARDS PROPOSAL

In June of 2023, The U.S. Department of Labor announced a proposal by its Mine Safety and Health Administration (MSHA) to amend current federal standards to better protect the nation’s miners from health hazards related to exposure to respirable crystalline silica, or silica dust. The proposal intends to lower the permissible exposure limit (PEL) for silica to 50 micrograms per cubic meter of air for a full shift exposure, calculated as an 8-hour time-weighted average. This is the same as the Occupational Safety and Health Administration’s (OSHA) current silica standard.⁴

Extensive sampling requirements are also proposed, as well as incorporating certain elements of ASTM F3387-19 Standard Practice for Respiratory Protection (ASTM F3387-19), including fit testing, respirator selection, inspection, and storage.

There’s also a medical monitoring element to the MSHA Silica proposal, which would help improve early detection of respirable crystalline silica-related disease with medical surveillance requirements for metal and nonmetal underground miners (MNM), modeled on existing medical surveillance requirements for coal miners.

OSHA REQUIREMENTS

OSHA requires all employers provide a medical evaluation to determine an employee’s ability to use a respirator prior to fit testing or respirator use occurring in the workplace.

Honeywell offers a series of respiratory protection programs designed for businesses and governmental agencies to help comply with OSHA requirements, including an Online Medical Evaluation Program and qualitative fit testing kits (Fit test methods: irritant smoke, bitter tasting, saccharine and isoamyl acetate) are amongst the best ways to assist your facility in achieving compliance and healthy work environment.  

For more information and additional resources, please contact your Honeywell respiratory specialist. 

SAFETY GOALS

As mining continues to experience extensive growth, especially in Canada and the United States, the health and safety of miners must be front and center. Between regulatory changes, continuous performance improvements, and utilizing reliable, effective PPE, the goal of a “culture of safety” in mining  can be achieved as the industry continues to play an integral role in the growing pursuit of global clean energy. 

SOURCES:

¹ https://natural-resources.canada.ca/our-natural-resources/minerals-mining/mining-data-statistics-and-analysis/minerals-and-the-economy/20529#Employment

² https://www.statista.com/statistics/193214/employment-in-total-us-mining-industry-since-1998/#:~:text=The%20United%20States'%20mining%20industry,to%20be%20an%20important%20industry

³ https://www.osha.gov/training/library/respiratory-protection/major-requirements#:~:text=For%20protection%20against%20particulates%2C%20the,42%20CFR%20Part%2084%3B%20or

⁴ https://ogletree.com/insights-resources/blog-posts/mshas-proposed-respirable-crystalline-silica-standard/