The latest on technologies to detect, monitor and control silica

By Justin Patts & Milan Yekich, NIOSH

Introduction

Researchers from the National Institute for Occupational Safety and Health (NIOSH) recently presented at the 2023 CalCIMA Spring Thaw to share their work towards managing the hazards of respirable dusts including respirable crystalline silica (RCS). While the problem of silica exposure in mining is as old as the industry itself – NIOSH has been investigating novel adaptations of existing technologies that can improve the ability to detect, monitor and lower miners’ exposure to RCS. With the Mine Safety & Health Administration (MSHA) considering lowering the existing RCS personal exposure limit, now is the right time to be on the lookout for solutions which can lower exposures in our mining operations.

LOW-COST DUST MONITORS

In the last 10 years, global demand to monitor air quality has led to the development of so-called “low-cost” particulate monitors, typically under $300 each.

NIOSH is conducting research to determine if the performance of these sensors is high enough to yield utility in operational mining environments. To accomplish this, testing is being conducted comparing the output of low-cost dust sensors and traditional sampling methods exposed to the types of dust found in the metal/ non-metal (M/NM) industry. Already seeing promise in the lab test results, researchers have begun preliminary case studies in operating mines to see how the sensors perform under representative real-world conditions.

NEXT-GENERATION CAB FILTRATION SYSTEMS:

NIOSH has conducted research on the performance of mobile equipment cab and control room filtration systems for more than 15 years and published extensively on the necessary components and characteristics for high-performing enclosure filtration. In their current research effort, they aim to specify, acquire, and demonstrate smart filtration and pressurization systems for mobile equipment. These smart filtration systems will be able to sense the air quality in real-time, change the operating parameters of the system to improve that air quality and then report the conditions both to the operator as well as remotely to the mine’s central maintenance dispatch. The goal is to have the best-possible air quality not just when the equipment is new but over its life cycle as seals deteriorate, filters load, etc.

RAPID QUARTZ ANALYSIS METHODS:

Having the ability to monitor exposure for RCS and doing so in a cost-effective and timely manner in the field is critical for selfassessment of compliance at the end of a shift. NIOSH researchers have developed the rapid quartz analysis, which is a 3-step field-based approach using a portable Fourier transform infrared (FTIR) analyzer in conjunction with the direct-on-filter analysis approach. This allows operators to estimate RCS on site, immediately after sampling, indicating if engineering controls need to be implemented. All the components are commercially available, in addition to the free download of the field analysis of silica tool (FAST) software to allow an occupational safety and health professional on-site to generate the exposure estimates right away. In addition, since the field methodology does not destroy the samples, the professional can, if needed, combine the benefit