Tailings storage is not only harmful to the environment, but also poses a great challenge to mine safety production. We consider whether coarse-grained tailings can replace standard sand in concrete to rationalize tailings’ valorization/consumption. Hence, this paper aims practicability of employing tungsten tailings to prepare shotcrete for roadway support and to explore the impact of tailings replacement (TR) rate on strength features and fine structural characteristics of coupled cemented tailings-sand concrete (CCTSC). The tailings weight replacement rate was set at 0 %-100 % with a gradient interval of 20 % in order to carry out the macro-mechanical strength and micro-mechanisms of action studies of CCTSC. Results illustrate that uniaxial compressive strength (UCS) of CCTSCs takes a linear distribution link with tailings’ replacement rate. When TR is 0 % and 100 %, the corresponding UCS of CCTSC is 4.86 MPa and 9.63 MPa, respectively, representing an increase of 98.1 %. A mixture of tensile and tensile-shear damage mainly characterizes the damage modes of CCTSC. The hydration materials of CCTSC are ettringite (AFt) and calcium silicate hydrate (CSH) gel. Hydration products gradually transitioned from Aft to CSH with increasing TR. The conclusions of the present investigation will afford data support for preparation of shotcrete support constituents for tungsten mine tailings, and its practical implementation will also have a major impact on subsequent use of tailings resources as well as low-cost green and smart mining of underground mines.

中文翻译：

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部分替代钨尾矿探索耦合水泥基尾砂混凝土的微观结构和力学特性


尾矿贮存不仅对环境造成危害，而且对矿山安全生产提出了巨大挑战。我们考虑粗粒尾矿是否可以替代混凝土中的标准砂，以合理化尾矿的增值/消耗。因此，本文旨在探讨利用钨尾矿制备喷射混凝土用于巷道支护的实用性，并探讨尾矿置换率（TR）对水泥尾矿砂耦合混凝土（CCTSC）强度特性和精细结构特性的影响。为了开展CCTSC的宏观力学强度和微观作用机制研究，尾矿重量替代率设定为0%-100%，梯度区间为20%。结果表明，CCTSC的单轴抗压强度（UCS）与尾矿置换率呈线性分布关系。当TR为0%和100%时，CCTSC对应的UCS分别为4.86 MPa和9.63 MPa，增加了98.1%。 CCTSC 的损伤模式主要以拉伸和拉伸剪切混合损伤为特征。 CCTSC的水化材料是钙矾石(AFt)和水合硅酸钙(CSH)凝胶。随着 TR 的增加，水合产品逐渐从 Aft 过渡到 CSH。本次调查结论将为钨矿尾矿喷射混凝土支护成分的制备提供数据支撑，其实际实施也将对尾矿资源的后续利用以及地下矿山低成本绿色智能开采产生重大影响。