Mining Contract: Cap Lamp Particulate Monitoring System

Contract Status & Impact

This contract is ongoing. For more information on this contract, send a request to mining@cdc.gov.

Coal seams are becoming smaller and more difficult to mine, and they require additional rock cutting which increases miners’ exposure to respirable silica. The best way to protect workers and provide information to mine operators is to have a real-time, silica-monitoring device integrated into existing equipment that mine workers currently wear.

This contract will develop a Cap Lamp Particulate Monitoring System (CPMS)—an integrated silica monitoring and tracking device—by leveraging research performed using multi-wave Raman light detection and ranging (LIDAR) to identify the optimal emitter and detector for the measurement of crystalline silica. The CPMS will alert miners when the silica permissible exposure limit (PEL) as established by the Occupational Safety and Health Administration has reached unsafe levels, or when an individual miner’s exposure to particulates has reached an unsafe level. To successfully develop this technology, two barriers must be overcome:

1. Identify the commercially available emitters and detectors that can be utilized.
2. Successfully integrate all the components into the helmet while meeting size and power restrictions of a cap lamp headpiece and waist-worn battery.

An intrinsically safe waist-worn battery approved by the Mine Safety and Health Administration (MSHA) for the Strata Personal Alarm Device and an intrinsically safe underground cap lamp will be leveraged to develop an intrinsically safe silica detection system that will be placed inside a cap lamp and waist-worn battery pack. The system will use infrared spectrophotometry, which is an accurate and widely used method to determine silica content. It will also incorporate the principles of Raman scattering.

Despite its potential for accuracy, the instrument’s cost, size, and data collection speed are major obstacles to making such a device mobile and operable in real time. Fortunately, advances in LIDAR technology incorporating Raman scattering measurements has shown great promise. A prototype of the CPMS will be developed through identification of optimal Raman backscattering wave-length emitters and detectors, testing and evaluation of commercially available off-the-shelf emitter and detectors on custom printed circuit boards, and integration of both an emitter and detector into the cap lamp.