Thermal Recovery of Backfilled Pit in the Gulianhe Strip Coalmine in the Hola Basin in Northern Da Xing’Anling Mountains, NE China

Frontiers in Earth Science

Futing Ma¹  Xinyu Li²  Huijun Jin³  Xiaoying Jin³  Meiquan Zhu³  Yadong Huang⁴  Yan Li⁴  Doudou Jin⁴  Hongwei Wang⁵  Ruixia He⁵ 

[1] Gulianhe Strip Coalmine, Heilongjiang, China;School of Civil Engineering, Harbin Institute of Technology, Harbin, China;School of Civil Engineering, Institute of Cold Regions Science and Engineering, Northeast-China Observatory and Research-Station of Permafrost Geo-Environment (Ministry of Education), Northeast Forest University, Harbin, China;School of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China;State Key Laboratory of Frozen Soils Engineering, Da Xing’anling Observation and Research Station of Frozen-Ground Engineering and Environment, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China;

关键词: strip coalmine;    Xing’an permafrost;    open-pit;    backfilling;    thermal recovery;    influencing factor;   

DOI  :  10.3389/feart.2022.806022

来源: DOAJ

【 摘 要 】

In the northern Da Xing’anling Mountains in Northeast China on the southern margin of the Eastern Asia permafrost body, the ground thermal state and boreal ecological environment are sensitive to climate change and human activities. Since the 1980s, the Hola Basin here has been continuously and extensively developed. In particular, open pits and later backfilling in strip coal mining alters land–atmospheric hydrothermal exchanges in permafrost regions, leading to serious damages to the permafrost environment and boreal forest. After mining, pits need to be backfilled timely and properly for hydrothermal recovery of Xing’an permafrost and the boreal ecological environment. In this study, based on the comparative analysis of monitored ground temperatures in backfilled and undisturbed areas, influencing factors of thermal recovery after backfilling were analyzed through numerical simulations. Results show that the thermal recovery of permafrost in the backfilled area is closely related to temperature, depth, material, and soil moisture content of backfill. The warmer, finer, and thicker the backfill soils, the longer the permafrost recovery. Thermal recovery of permafrost also depends on the moisture content of backfill; the shortest recovery occurs at 15–25% in the backfilled soil moisture content. Based on numerical simulations and combined with enlightenments from features of the ecosystem-protected Xing’an permafrost in Northeast China, a composite configuration of organic soil, crush-rock layer, and proper re-vegetation measures is advised. Based on prudent regulation of heat transfer modes, this composite backfilling method can effectively cool the backfilled ground and can even possibly offset the climate warming.

【 授权许可】

Unknown