Retrospective Analysis of the Gas Balance and a Concept for Spatially Differentiated Mine Methane Capture: A Case Study of the Karaganda Coal Basin, Kazakhstan

This study quantifies discrepancies between design and actual gas-emission indicators and distinguishes changes in absolute methane inflow from production normalization in interpreting mine gas balances. The retrospective sample comprises nine longwall panels in seams D6 and K10 at five mines in the Karaganda Coal Basin. The procedure combined paired comparisons of aggregate indicators, arithmetic checks of methane-removal pathways, recalculation of specific emissions from flow and production, exact symmetric decomposition, and sensitivity checks for sample composition and aggregation level. The mean actual-minus-design specific-emission difference was 8.18 m3/t (95% confidence interval 0.79–15.57; paired t-test p = 0.034), whereas the Wilcoxon test yielded p = 0.0586 and the interval with equal weights for five mines included zero (−2.77–23.04 m3/t). For the recalculated indicator, the mean difference of 8.30 m3/t comprises a flow component of 2.47 m3/t and a production-denominator component of 5.83 m3/t. The absolute-flow difference relative to flow reconstructed at design production was not statistically significant (5.35 m3/min; p = 0.594). The mean panel-level controlled-removal share was 77.39%, and the ratio of summed flows was 79.11%; neither is a utilization fraction. The contribution is a quantitative distinction between inflow discrepancies and production-normalization effects, with explicit accounting boundaries and aggregation choices. Spatially differentiated capture is formulated as an engineering hypothesis; small sample size, within-mine dependence, and missing metrological documentation limit generalization.