高原高寒矿区生态修复中的煤炭资源保护技术

Techniques for coal resource conservation during the ecological restoration of alpine mining areas on plateaus

【目的】木里煤田地处青藏高原东部高寒地区,长期的煤炭开采对当地生态环境造成了一系列问题,其中主要问题之一是露天采区存在大量已扰动的煤炭资源,因此需研究生态修复与资源保护的协同,探索如何在矿区生态恢复过程中实现煤炭资源的科学、有效保护方法。【方法】以木里煤田聚乎更矿区为例,在分析露天采区煤炭资源破坏特征的基础上,从地质机理分析的角度出发,按照生态地质层构建方法,采用人工方式构建残留煤层顶板及上部保护层,并充分利用矿区地质环境条件,兼顾资源集约利用、经济性、与景观协调性的原则,因地制宜,分区分类施策,将煤炭资源保护有机融合于矿区生态修复过程中,建立了两种煤系矿产资源保护技术,分别为:人造冻土层煤层顶板生态地质层构建技术和“以水代填”煤炭资源保护技术,其中人造冻土层煤层顶板生态地质层构建技术可进一步分为边帮煤层保护技术、采坑底部煤层顶板模拟冻土层技术和自燃煤层治理保护技术。【结果和结论】通过探坑实地测量验证,治理完成18个月后,人工构建的煤炭资源保护层已逐步恢复并初步形成冻土层,热融季消融深度为1.8~2.3 m,形成了新的煤层保护层。“以水代填”兼顾了经济性的同时,实现了煤层保护与景观协调性的统一,取得了良好的应用效果。探索形成了高寒矿区煤炭资源保护与生态修复协同的新思路,为类似地区露天煤矿生态修复治理提供参考。

[Objective]The prolonged coal mining of the Muli coalfield,located in an alpine region in the eastern Qinghai-Tibet Plateau,has posed many ecological challenges,which especially include the presence of considerable quantities of disturbed coal resources in open-pit mining areas.This study aims to achieve scientific and effective coal resource conservation during the ecological restoration of coal mines.[Methods]Focusing on the Jvhugeng mining area of the Muli coalfield,this study investigated the destruction characteristics of the coal resources in the open-pit mining area.From the perspective of geological mechanisms behind the destruction, this study artificially constructed the roofs of residualcoal seams and their overlying protective layers using the method for constructing eco-geological layers. By fullyleveraging geologic environments in the mining area while considering intensive resource utilization, economic viability,and coordination between resources and landscapes, this study integrated coal resource conservation into the ecologicalrestoration of the mining area using countermeasures tailored to zones and categories based on local conditions. Accordingly,this study developed two techniques for coal measure resource conservation: the technique for constructing coalseam roofs using artificial frozen soil layers as eco-geological layers and the technique for coal resource conservation byreplacing backfill with water. The former technology can be further divided into the conservation technique for slopecoal seams, the technique for simulating frozen soil layers as the roofs of coal seams at the mining pit bottom, and thetechnique for managing and conserving coal seams subjected to spontaneous combustion. [Results and Conclusions]Field measurements of test pits reveal that 18 months after control, the artificially constructed coal resource conservationlayers had progressively recovered and preliminarily formed frozen soil layers. During the melting season, thefrozen soil layers exhibited melting depths ranging from 1.8 m to 2.3 m, leading to the formation of new coal seam conservationlayers. Replacing backfill with water contributes to both coal seam conservation and landscape coordinationwhile considering the economic viability, suggesting satisfactory application effects. This study, developing a novelphilosophy for the coordination between coal resource conservation and ecological restoration in alpine mining areasthrough exploration, provides a reference for the ecological restoration and control of open-pit coal mines in similar regions.