Mining Contract: Personal Air Safety System (PASS)

Contract Status & Impact

This contract is complete. To receive a copy of the final report, send a request to mining@cdc.gov.

Underground mining makes increasing use of diesel-powered mining equipment as well as blasting. Because the machinery is operated and the blasting occurs in an enclosed space, high concentrations of potentially harmful air contaminants can be generated. Diesel-powered equipment exhaust products—most notably nitrogen dioxide (NO₂), carbon monoxide (CO), and diesel particulate matter (DPM)—are known to be potentially hazardous air contaminants. While some devices exist to detect these, they are often fairly bulky and expensive, with no connectivity to other systems.

To address this problem, OMSHR is interested in providing mine workers with a monitor that allows them to individually track their exposure to these air contaminants in real time. Because miners work in confined areas with heavy machinery in operation and significant extremes in temperature, vibration, and shock, this monitor must be affordable, easily wearable, very small, and extremely rugged, while able to alert the mine worker through multiple means (i.e., without dependency on a single method to alert the worker to danger). A wireless capability to pass on alerts would be of considerable additional use.

This contract research supports the development of PASS (Personal Air Safety System)—a miniature sensor system small enough to be attached to nearly any convenient location such as the belt, mounted on or integrated within the helmet or a strap, or possibly integrated into ear protection currently worn. PASS builds on the International Electronics Machine (IEM) Corporation’s prior miniature wired and wireless sensor systems for military and commercial vendors. This technology will also take advantage of Commercial Off-the-Shelf (COTS) sensor technology and innovative methods for power cycling to ensure constant operation throughout even multiple shifts between recharges.

The basic PASS unit will track the concentrations of nitrogen dioxide and carbon monoxide and use sight, sound, and vibration to alert the wearer when specific concentration limits are exceeded. This may include tracking concentration levels over time and producing a time-weighted average for exposure (especially for carbon monoxide). Additional PASS development could include the ability to measure and track exposure limits in more advanced ways and to measure the presence of DPM. PASS must also be designed to meet MSHA permissibility requirements for intrinsic safety. Current sensing monitors are used for detecting gases such as methane; PASS could later integrate such capacities as well.