露天矿内排土场近自然地貌重塑研究——以新疆黑山露天矿为例

Research on the reshaping of the near-natural landform of the internal dump for open-pit mine:a case study of Heishan Open-Pit Mine,Xinjiang,China

露天开采作为我国矿产资源的主要开发形式,其长期高强度人为扰动形成的传统“梯田式”内排土场面临占地面积大、景观破碎等问题。近自然地貌重塑作为矿区修复的重要手段,具有融合矿区内外景观的独特优势。为设计与周边自然地貌相融合的露天矿内排土场地貌,在现有开采工艺基础上,提出一种采排复一体下基于调整曲面的内排土场近自然地貌重塑模型;以新疆黑山露天矿为例,构建内排土场近自然设计地貌,及区域原始地貌和传统设计地貌2个对照组,结合CLiDE演化模型,模拟并评价10 a内近自然设计地貌的抗水蚀效果。结果表明:①地貌设计上,近自然地貌重塑模型在采排复一体化过程中可依据采复子区采前地表、矿层顶板及底板数字高程数据,自动求解复填可用土方量,获取复填子区地表高程近自然设计结果;②土方调配上,近自然设计地貌土方平均运距较传统设计地貌高0.49 m/m^(3),较后者高约0.06%,两者土方平均运距极为接近;③视觉上,近自然设计地貌能够与周边自然景观相融合,相较传统“梯田式”地貌,其与周边自然地貌间无明显拼接痕迹;④土壤水蚀模拟上,近自然设计地貌较传统“梯田式”地貌10 a可减少约39.07%的土壤水蚀量,其可显著提高内排土场表土抗水蚀能力;⑤土壤运移演化上,近自然设计地貌表土流失及堆积区的空间位置与自然原始地貌重叠率达57.27%,较传统设计地貌高2.96%,其区域表土运移特征与采前自然地貌更为接近。

Open-pit mining is the main development form of China’s mineral resources.In the process of open-pit mining,the traditional“terraced”internal dumps formed by long-term high-intensity human-made disturbances face problems such as large area and fragmented landscape.As an important means of restoration of the mining area,the near-natural landform remodelling has the unique advantage of in⁃tegrating the landscape outside the mining area.In order to design an open-pit mine dump that is integrated with the surrounding natural landforms,based on the existing mining technology,this research proposes a near-natural landform remodelling of the internal dump by the adjustment of the curved surface under the integration of mining-disposal-refilling.Taking the Xinjiang Heishan open-pit mine as an example,the paper constructs the nearly natural design landform of the inner dump and two experimental control groups,including natural primitive landform and traditional design landform.Finally,the CLiDE evolution model is used to simulate and evaluate the nearly natural design landform’s anti-water erosion effect within 10 years.The results show that:①In terms of geomorphology design,the near-natural geomorphology reshaping model can show according to the DEM before mining,the DEM of mine roof and the DEM of mine floor during the mining-disposal-refilling integration process to get the available earthwork for the refilling automatically and then obtain the near-nat⁃ural design results of DEM of the refilling sub-area;②In terms of earthwork allocation,the average earthwork distance of the nearly nat⁃ural design landform is 0.49 m/m^(3) higher than that of the traditional design landform,which is about 0.06%higher than the latter.Their average earthwork distance values are very similar;③Visually,the near-natural design landform can be integrated with the surrounding natural landscape.Compared with the traditional“terraced”internal dump,there is no obvious splicing mark between it and the surround⁃ing natural landform;④In the process of soil water erosion simulation,the nearly natural design landform can reduce the amount of soil water erosion by about 39.07%compared with the traditional“terraced”landform in 10 years,which can significantly improve the water erosion resistance of the internal dump’s topsoil;⑤In terms of soil migration and evolution,the spatial location of the topsoil loss area and accumulation area of the nearly natural design landform has an overlap rate of 57.27%with the original natural landform,which is 2.96%higher than that of the traditional design landform.The surface soil migration characteristics of the near-natural design landform are more similar to the natural landform before mining.