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This study proposed the multi-coupling grouting system with the aim to tackle green mine problems such as surface collapse, water resources destruction and coal based solid waste accumulation.Successfully applied, this system yielded the following major achievements: this study (1) probed into the patterns of development and evolution in mining separation space and primary fracture space, and conducted the intelligent identification of grouting space by means of theoretical analysis, physical and numerical simulation and field detection.(2) prepared multi-source inorganic high-performance grouting materials for different scenarios by using coal-based solid wastes (coal gangue, fly ash), and developed a new KEP grouting material with underwater dispersion resistance, high volume coefficient and high plastic strength.(3) applied cluster well and feather well to grouting hole drilling and and developed an all-weather, high pump pressure and large flow intelligent grouting system; The reinforcement grouting technology is applied for the first time to strengthen the effect of grouting to reduce settlement.(4)put forward the technology system of grouting effect monitoring and detection, and emphatically expounded the borehole detection method of combining drilling core and well logging.(5)formed an intelligent technology system based on the methods of separation space grouting to reduce settlement and treat waste, caving zone grouting to treat waste, goaf grouting to strengthen foundation bearing capacity and treat waste, and roof fissure grouting to control water gushing as the core.Engineering demonstrations of this system have been carried out in Xiadian coal mine, Xinpu phosphate mine, Caojiatan coal mine, Gaojiabao coal mine and other places, which yielded good results.

Zn1−xMgxTe crystal is expected to be less harmful, more efficient, and economical as a blue-green LED material. In this study, Zn1−xMgxTe and P:Zn1−xMgxTe crystals with different x (0.06 ≤ x ≤ 0.25) values were prepared by the travelling Te solution method. The required polycrystalline materials for crystal growth were successfully synthesized by an element direct reaction method. The XPS results demonstrate that the Mg element is present in Zn1−xMgxTe polycrystalline as Mg2+. The lattice constants of zinc-blende Zn1−xMgxTe are approximately linearly dependent fitted as α(x) = 6.107 + 0.18x (Å). The Mg content dynamic equilibrium between the source materials, Te solution and crystal was anticipated to be progressively achieved throughout the crystal growth and then the segregation of the Mg in the as-grown crystal is reduced. The ranges of fluctuations in the Mg contents for Zn0.90Mg0.10Te and Zn0.75Mg0.25Te were 0.092–0.104 and 0.212–0.227, respectively, along the radial direction. When compared to the calculated values found in the literature, there is less axial segregation of the Mg component during the crystal growth. The Mg content along the axial direction of the crystal of Zn0.82Mg0.18Te increases at a rate of around 0.0047 cm−1, which is significantly less than that of Zn0.80Mg0.20Te crystal grown by the melting method (0.028 cm−1). As-grown Zn0.90Mg0.10Te and Zn0.75Mg0.25Te crystals have infrared and UV-vis-NIR transmittance values close to 60%, and their bandgaps are between 2.2 eV and 2.4 eV, respectively. The resistivity of intrinsic Zn0.75Mg0.25Te crystals is as high as 1.62 × 108 Ω cm. The lowest resistivity of P:Zn0.92Mg0.08Te crystals with p-type conduction is 28.6 Ω cm, and the greatest hole concentration is 8.02 × 1016 cm−3, according to the results of the Hall test. [ABSTRACT FROM AUTHOR]

The rock-breaking mechanism and effect of confined blasting were analysed by blasting and impact dynamic mechanics, fluid dynamic mechanics, fracture mechanics as well as blasting experiment. The results showed that the fracturing of surrounding rock in confined blasting condition is the result of coaction of rock pre-cracking by shock wave and stress wave and the continuing expanding crack-enhancement of confined medium, and the model of crack development of borehole surrounding rock in confined blasting condition was established. This study acquired the damage range of surrounding rock under the action of shock wave and stress wave, as well as the crack development characteristics of surrounding rock after the wedge-in confined medium into the crack space. Deep-hole confined blasting experiment on large rock showed that the high-efficient utilisation of in-hole explosive was achieved and the safety of rock blasting operation was ensured. Safe static rock-breaking under the action of high-efficient explosive blasting was achieved as well as the unification of super dynamic load of explosive blasting and static rock-breaking of water medium. Keywords: Shock wave, Confined medium, Water-wedge action, Crack development, Confined blasting

The mining confrontation caused by a super-long working face is an important factor that leads to difficulties in the control of surrounding rock in facing-mining roadways. To address this issue, this study takes the 18106 working face of Xiegou Coal Mine as the engineering background. First, deformation characteristics of the surrounding rock in two stages of roadway mining are explored, and the principle of determining the time for fracturing construction is presented. Additionally, the influence of fracturing space position on the control effect of the roadway's surrounding rock is examined. Results show that the roadway which is influenced by adjacent working face mining has obvious asymmetric deformation, and the order of deformation is as follows: pillar side > roof > coal side > floor. The roof activity in goaf is the key factor of roadway deformation, and the proportion of deformation is 60%, followed by the influence of advance stress, accounting for 38%. After fracturing, with the increase in fracturing height, the deformation of the surrounding rock decreases, and the decrease in deformation of the roof and two sides also reduces, while the decrease in deformation of the floor remains relatively stable. The reasonable fracturing height is 10 m, and the reasonable fracturing construction time is 17 days before the confrontation between the working face and the roadway. Field practice suggests that there are effective cracks in the roof after fracturing, and the deformation of the surrounding rock in facing-mining roadways is reduced by more than 60% compared to that without fracturing. Hydraulic fracturing is significant for controlling the deformation of the surrounding rock in facing-mining roadways. [ABSTRACT FROM AUTHOR]