Measurement & analysis

Distributed Measurement of Conductor Temperatures in Mine Trailing Cables Using Fiber-Optic Technology (PDF, 63 KB, 1998-03)
Mine trailing cables operated above safe thermal limits can cause premature insulation failure, increasing electrocution and fire hazards. This paper describes a unique approach to measuring temperatures within reeled cable under dynamic test conditions.

Optically Powered Remote Gas Monitor (PDF, 1565 KB, 1995)
Many mines rely on toxic gas sensors to help maintain a safe and healthy work environment. This report describes a prototype monitoring system developed by the U.S. Bureau of Mines (USBM) that uses light to power and communicate with several remote toxic gas sensors.

Remote Fiber-Optic Methane Monitor (PDF, 1160 KB, 1992)
Reports on the U.S. Bureau of Mines development and testing of an instrinsically safe methane monitor based on differential absorption of infrared light.

Engineering controls

Continuous Wave Laser Ignition Thresholds of Coal Dust Clouds (PDF, 94 KB, 2003-08)
Laser-based instruments are used in areas where coal dust ignition presents a safety hazard. NIOSH is conducting a study to help determine when an optical beam may be considered a potential ignition source in underground coal mines or coal storage facilities.

Ignition of Methane-Air Mixtures by Laser Heated Small Particles (PDF, 790 KB, 2000)
Optical technologies have progressed rapidly in the past 15 years. NIOSH is conducting a study to help provide a scientific basis for developing appropriate safety guidelines for optical equipment in underground coal mines.

Ignition Tests With a Fiber-Optic Powered Instrument (PDF, 388 KB, 1996)
New types of industrial instruments use fiber-coupled laser energy to power remote sensors. The U.S. Bureau of Mines began an investigation of laser-powered fiber-optic instruments in explosive atmospheres in support of the standard-making process.

Laser Ignition of Flammable Gas (PDF, 512 KB, 1999)
Emerging laser technologies are quickly gaining acceptance in the industrial workplace. The National Institute for Occupational Safety and Health is conducting research to help provide a scientific basis for developing appropriate safety guidelines for optical equipment in the presence of flammable methane gas and/or coal dust.

Laser Safety in Underground Coal Mines (HTM, 2001)
New laser technologies are being developed for a variety of applications. In the coal mining industry, lasers can be used to detect the presence of dangerous gases, to monitor the level of coal in storage facilities, and to survey the underground mine, to name a few applications.

Methane-Air Mixtures Ignited by CW Laser-Heated Targets on Optical Fiber Tips: Comparison of Targets, Optical Fibers, and Ignition Delays (PDF, 2042 KB, 2006-09)
Researchers conducted experiments to estimate the mean and standard deviation of laser powers needed to ignite 6% methane-air atmospheres using single mode optical fiber tips covered by two types of iron oxide (Fe3O4 and (FeMn)(2)O-3) mixed with a ceramic adhesive.

Threshold Powers and Delays for Igniting Propane and Butane-Air Mixtures by CW Laser-heated Small Particles (PDF, 903 KB, 2006)
The National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory conducted a study of laser safety in potentially flammable environments. Researchers measured threshold igniting powers as a function of beam diameter for butane and propane-air mixtures by laser-heating targets placed on optical fiber tips using a 1064 nm laser.

Information gateways

ISA Committee - ISA-SP12.21, Fiber Optics (http://www.isa.org/mstemplate.cfm?micrositeid=156&committeeid=4618)
This committee prepares standards and recommended practices for the construction, test, and installation of fiber optic systems intended for instrumentation and communication systems in hazardous (classified) locations.