The use of diesel-powered equipment in underground coal mining has grown substantially during the past 20 years. The periodic measurement of carbon monoxide (CO) in the exhaust of such equipment is mandated by several states and by federal regulations (MSHA) in order to assess engine operating conditions and compliance with engine exhaust emission limits. Both Pennsylvania and West Virginia state regulations limit the tailpipe CO concentration of mining equipment used in underground coal mines to 100 parts per million (ppm) at any time under a normal engine operating temperature range. The tailpipe field measurement of CO on a unit of diesel-powered mining equipment can be performed with several commercial devices. Most of these devices consist of a sampling probe, a sample conditioner, an analytical unit and a pump to draw the sample. For underground mining applications, the analytical unit is usually an electrochemical cell. The choice of the electrochemical cell is particularly important because the cell has to provide reliable measurement in the range of interest. Generally, the function of the sample conditioner is to remove water vapor, diesel particulate matter (DPM) and other compounds from the sample that might affect the measurement. Currently, two commercially available instruments are being used to measure tailpipe CO concentrations from diesel-powered mining equipment in West Virginia coal mines. One of these instruments is generally used as an ambient monitoring device, and questions have been raised concerning its accuracy when this instrument is used to measure tailpipe CO concentrations. The subject of this informational report is the comparison of these two field instruments with a reference laboratory analyzer when challenged with the same sample extracted from a diesel engine exhaust tailpipe.
Mining-industry; Mining-equipment; Diesel-emissions; Diesel-engines; Diesel-exhausts; Equipment-reliability; Regulations; Coal-mining; Underground-mining; Testing-equipment; Measurement-equipment; Oxides; Emission-sources; Motor-vehicle-parts; Motor-vehicles; Exhaust-gases; Exhaust-systems; Gases; Exposure-levels; Exposure-limits; Machine-operation; Electrochemical-analysis; Sampling-equipment; Sampling-methods; Sample-preparation; Analytical-instruments; Analytical-processes; Laboratory-equipment