Thematic Evolution and Policy Design Consistency in China’s Coal Mine Methane Policy: Evidence from LDA and PMC Analysis

Coal mining is a major source of energy-related methane emissions; coal mine methane (CMM) governance is therefore relevant to climate mitigation and environmental sustainability. However, systematic evidence remains limited on how policy attention has evolved across China’s CMM policy system and how key design elements are configured within individual policies. This study examines the thematic evolution and policy design consistency of China’s CMM policies from 1988 to 2025. Latent Dirichlet Allocation (LDA) was applied to 163 policy texts, and the Policy Modeling Consistency (PMC) Index was used to assess 12 selected policies. Four themes were identified: CMM extraction and utilization, coalbed methane resource planning and regulation, methane utilization and low-carbon transition, and coal mine gas safety management. Coal mine gas safety management remained recurrent, while methane utilization and low-carbon transition became more prominent in later years. The PMC assessment indicated acceptable-to-excellent overall consistency but uneven dimensional coverage; Policy Timeliness, Policy Instruments, and Policy Object had the lowest mean scores. These findings indicate that policy timeliness, instrument configuration, and target-actor specification warrant particular attention in future CMM policy design.