Evaluating Pellistor sensors for reporting of methane emission in coal mine ventilation: Toward low-cost reporting solutions

• OP-TDLAS enables precise shaft-scale monitoring. Continuous, line-integrated measurements yielded 1.854 kt over one month and support annual reporting with an uncertainty of ∼0.015 kt per year. • Pellistor sensors are viable for reporting with routine calibration. With weekly or fortnightly calibration and drift correction, Pellistors reproduced OP-TDLAS emissions within 0.3 percent over one month; expected annual bias is < 0.1 kt where lasers are not feasible. • Uncertainty targets are achievable for compliance. For ventilation-shaft emissions, attainable uncertainties are ∼0.015 kt per year using OP-TDLAS and ∼0.25 kt per year using Pellistors, aligning with measurement-based reporting requirements. This study investigates the feasibility of using a catalytic Pellistor sensor as a cost-effective solution for continuous methane emission monitoring in mine ventilation shafts and channels, in line with the requirements of Regulation (EU) 2024/1787 on methane emissions from the energy sector. The primary aim was to determine whether a Pellistor-based system, when appropriately calibrated and operated, can meet the regulation’s expanded uncertainty target of 5 percent for methane emission values while offering practical advantages for long-term deployment in challenging mining environments. Field measurements were carried out at the Pniówek coal mine using a single Pellistor unit positioned within a high-turbulence, constant cross-section ventilation shaft, alongside a laser-based infrared open-path analyzer (LasIR OP-TDLAS) for cross-section concentration measurements. Calibration used reference gases traceable to national metrology standards, with performance verified at regular intervals. Known influences on Pellistor performance such as humidity, potential hydrogen interference, and sensor drift, were systematically addressed through instrument selection, gas chromatographic cross-checks, and zero/span stability monitoring. Methane concentration homogeneity in the diffuser section was confirmed using an off-axis integrated cavity output spectrometer (LGR OA-ICOS) during dedicated tests, eliminating the need for computational fluid dynamics modelling. The averaging over the cross-section of the shaft and over the reporting integration period effectively smooths short-term variability in methane concentration, ensuring representative values for compliance assessment. The results demonstrate that the tested Pellistor system achieved expanded uncertainties within the 5 percent target for methane emission values, while reducing equipment and operational costs by approximately 95 percent compared with advanced open-path laser optical analyzers. These findings highlight the potential for well-maintained Pellistor installations to provide compliant, reliable, and economical continuous methane monitoring for mining operations.