The opencast Bilina coal mine (Czech Republic) produces eight million tons of subbituminous coal per year. To evaluate greenhouse gas emissions from the mine, we measured the chemical and isotopic composition of gases released from fresh coals using the canister method and after coal crushing and milling. The δ¹³C values of the released methane (CH₄) and carbon dioxide (CO₂) corresponded to their biogenic origin (δ¹³C (CH₄) −70 ‰ to −55 ‰ vs. VPDB, δ²H − 275 ‰ to −260 ‰ vs. VSMOW, δ¹³C (CO₂) -10 ‰ to −16 ‰ vs. VPDB). The findings revealed that secondary biogenic gas production replaced original coal bed gases and the excavated coal is rich in CO₂ (0.615 m³ ton⁻¹), but very low in CH₄ (0.09 m³ ton⁻¹). Additionally, most of the secondary CH₄ was released before excavation. The loss of CH₄ (0.235 m³ ton⁻¹) was calculated back from the isotope fractionation of residual CO₂. High CO₂ emission increased its atmospheric concentration in the mine (570–2000 ppm).

露天 Bilina 煤矿（捷克共和国）每年生产 800 万吨次烟煤。为了评估该矿的温室气体排放量，我们使用罐法以及煤破碎和碾磨后从新鲜煤中释放的气体的化学和同位素组成进行了测量。释放的甲烷 (CH ₄ ) 和二氧化碳 (CO ₂ )的 δ ¹³ C 值与其生物来源相对应（δ ¹³ C (CH ₄ ) -70 ‰ 至 -55 ‰ vs. VPDB，δ ² H - 275 ‰至 -260 ‰ 与 VSMOW，δ ¹³ C (CO ₂) -10 ‰ 到 -16 ‰ 与 VPDB)。研究结果表明，二次生物气产量取代了原始煤层气，开采的煤富含CO ₂（0.615 m ³ ton ^-1），但CH ₄含量非常低（0.09 m ³ ton ^-1）。此外，大部分次生CH ₄在开挖前已释放。CH ₄的损失（0.235 m ³ ton ^-1）由残余CO ₂的同位素分馏计算。高 CO ₂排放增加了其在矿山中的大气浓度（570–2000 ppm）。