Mining Project: Evaluation of LIDAR as a Novel Remote Dust Sensing Technology

Research Summary

The goal of this research was to evaluate the feasibility of using Light Detection and Ranging (LIDAR), a remote sensing technology analogous to RADAR, as a dust monitoring tool in the mining industry. LIDAR is a remote sensing technology that can rapidly scan large volumes for contaminants. MSHA issued a final rule reducing the exposure limit for respirable coal mine dust from 2 mg/m³ to 1.5 mg/m³ effective in August, 2016. To achieve lower exposures without negatively affecting production levels, a better understanding is needed of the sources and transport of respirable dust and how to optimize the performance of dust controls. If LIDAR can be utilized in mining to remotely monitor the location and movement of dust, new opportunities to reduce the exposure of miners to respirable dust will become available. This project was the initial evaluation of light detection and ranging technology (LIDAR) by NIOSH for remote dust source and transport monitoring.

This project directly supports the NIOSH Mining Program Strategic Goal 1, to "Reduce respiratory diseases in miners by reducing health hazards in the workplace associated with coal workers’ pneumoconiosis, silicosis, and diesel emissions."

The ability of LIDAR to remotely determine the location and movement of airborne dust was examined. Tests were conducted in the longwall and continuous miner model mine galleries at the Bruceton Research Center. The following tasks were completed during this project:

1. Test the ability of the LIDAR system to function in a volume that includes complex structures. The "vision" of the LIDAR system was evaluated to determine its ability to successfully scan the length of the longwall gallery face.
2. Test the effect of various dust concentrations on the LIDAR system. Multiple dust concentrations within the range observed on actual longwall and continuous miner faces were used to challenge the LIDAR system.
3. Test the effect of various air velocities on the LIDAR system. Two air velocities were used on the longwall gallery to determine if the LIDAR can observe the location and movement of dust under these conditions. One velocity was used on the continuous miner gallery.

The LIDAR system output qualitatively matched sample results obtained with nephelometric data logging instruments typically used to monitor airborne respirable dust; however, differences in the magnitude of the concentrations reported by the two methods existed.  Potential reasons for the observed differences include the LIDAR's heightened response to very small dust particles due to the interaction with the laser wavelength, response of the LIDAR to particles larger than respirable size, and assumptions made regarding particle shape when estimating the extinction coefficient for concentration estimates.