Mining Project: Design of Proximity Systems for Underground Mobile Equipment

Research Summary

Coal mining deaths, for surface and underground mining combined, dropped from 20 in 2013 to 16 in 2014—the lowest number of coal mining deaths ever recorded annually in the United States. Of those 16, the majority (10) occurred in underground coal. Six of those occurred when the miner was either struck or pinned by mobile haulage equipment. According to 2010-2014 data from the Mine Safety and Health Administration (MSHA), there are an average of 6.2 fatal accidents per year of this type. In each of the previous five years, underground mobile haulage equipment was the source of the majority of fatalities in underground coal mining. MSHA has published a proposed rule  to require proximity detection systems on mobile equipment in underground mines.

Surveillance data from MSHA, along with input from mining industry stakeholders, have defined the need for design guidelines to develop advanced proximity systems for mobile equipment. To address this need, this project research provided guidance and information to MSHA and proximity system manufacturers to improve proximity detection systems for the protection of underground personnel from accidents and fatalities caused by underground mobile haulage equipment.

This project had two research aims designed around several research questions, as follows:

1. What are the design parameters for proximity warning systems on mobile haulage equipment that provide optimum protection for underground workers while ensuring they cause no additional risk of injury to the operator? What actions should these systems take and when, where, and why should they activate? Should different actions be taken in different parts of the mining operation?
2. Do current MSHA-approved systems provide optimum protection or are other proximity detection technologies besides those currently approved for use in underground coal mines needed for mobile underground haulage equipment? Would technologies such as sonar, radar, radio frequency identification (RFID)-based, and other sensor technology apply to underground mobile haulage equipment and what additional protections would these technologies provide? Could new technologies, such as RF wireless access points, be used for triangulate positions of vehicles and workers?

NIOSH conducted research to improve the performance of current proximity detection systems (PDSs) by investigating scenarios where their performance might be adversely impacted and developing innovative solutions to mitigate those effects. Examples of the scenarios investigated include the electromagnetic interference (EMI) issue caused by a personal dust monitor (PDM) to a PDS and the environmental influence caused by trailing cables and steel mesh that are commonly used in underground coal mines.

The results and findings from this project benefitted NIOSH stakeholders including regulatory agencies, designers, installers, and those maintaining mine safety systems by defining how proximity systems should function and be evaluated to prevent traumatic injury from pinning and struck-by accidents. Mitigation strategies developed for EMI and environmental influences helped to enforce a consistency about the function and behavior of PDSs which led to better acceptance by underground workers. Properly designed PDSs improved the safety of underground workers, thus causing a reduction in striking and pinning accidents involving underground mobile equipment.