The backfill binder material is the key to the cost and performance of cemented paste backfill. This study aims to understand the current situation of metal ore backfill binders, identify industry challenges, inspire research ideas, and explore development directions. Current research investigates trends and developments of backfill binders through literature review, experience summary, field research, statistical analysis, and other methods. Firstly, the main backfill binder types are summarized, including cement, metallurgical slag, thermal slag, chemical slag, and tailings binders. Secondly, the research progress regarding reactivity activation, hydration mechanism, harmful ion solidification, energy conservation, and carbon reduction is summarized. Thirdly, three industrial applications of new backfill binders are introduced and summarized. Cement is still the most common, followed by slag powder binder. The cases of steel slag binder and semi-hydrated phosphogypsum backfill have shown significant effects. Solid waste-based backfill binder materials are gradually replacing cement, which is a trend. Finally, further research is discussed, including hydration modeling and simulation, material properties under extreme environments, hardening process control, and technical standards for backfill binders. This work provides a reference and basis for promoting green and efficient paste backfill and sustainable industry development.

The high consumption and high cost of cement are the bottleneck problems that limit the development of cemented tailings backfilling technology. The low-consumption cement backfill is immersed in a weak acid/alkaline groundwater environment for a long time. Reducing the consumption of cement can easily lead to problems such as a sudden decrease in strength and the leakage of heavy metals. Through the monolithic leaching test in static and uniaxial compressive tests, the heavy metals’ leaching concentration and the compressive strength of low-consumption cement backfills in different pH soaking solutions were measured at different soaking times. Results show that a lower cement concentration will result in a lower CTB compressive strength and a higher rate of heavy metal leaching. Long-term exposure to an acidic/alkaline environment will lead to the instability and destruction of the CTB structure. A microscopic examination reveals that the creation of hydration products can improve the structure’s compactness while also lowering the internal porosity of CTB but can also solidify heavy metal ions in various ways. A first-order reaction/diffusion model (FRDM) can better evaluate the leaching behavior of CTB. This study helps to improve backfilling technology, thereby contributing to the creation of sustainable mining geotechnologies.

Under the background of intelligent construction of coal mines, gas extraction design is still based on manual design, which is complex, time–consuming, and error–prone, and its automation degree needs to be improved. In order to solve this problem, taking the 1302 working face of a mine in Shanxi Province as the research object, this paper carried out relevant research. Firstly, the influencing factors of gas extraction were determined, and the influence rules of different parameters on the extraction effect were studied by numerical simulation. Secondly, an intelligent optimization method of gas extraction drilling parameters based on deep mining called the PSO–LSTM model, is proposed. This model uses the PSO algorithm to optimize the parameters of the LSTM model, so as to improve the accuracy of the LSTM model results. Finally, a quantitative expression algorithm of 3D spatial information of gas extraction drilling holes based on Python is proposed, which can automatically generate 3D spatial models of bedding or through gas extraction drilling holes using optimized drilling parameters and known 3D information of coal seams. This study shows that the results obtained using the PSO–LSTM model are the same as the drilling parameters obtained using numerical simulation, which verifies the accuracy of the PSO–LSTM model. According to the optimized drilling parameters, a 3D model of gas extraction drilling is quickly generated, which greatly reduces the tedious work of drawing construction drawings for coal mine enterprises and improves the intelligence level of coal gas extraction drilling.

To investigate the thickening characteristics of ultrafine tailings and the relationship between bed height and underflow concentration, a series of experiments, including graduated cylinder sedimentation tests, small-scale dynamic thickening, and semi-industrial experiments, were conducted. The results show that adding flocculants accelerates settling velocity, with a significant change occurring at 50 g/t when the bridging effect weakens. Solid flux increases initially with feed concentration but decreases after reaching a peak at 8%, where the maximum solid flux is 0.322 t·m⁻²·h⁻¹. Reducing solid flux, lowering flocculant dosage, and increasing bed height all contribute to higher underflow concentration, while reducing solid flux and increasing flocculant dosage lowers overflow turbidity. The variation in underflow concentration in the deep cone thickener (DCT) occurs in three phases: continuous feeding with no discharge, dynamic equilibrium with a stable bed height, and bed descent with increasing underflow discharge. At the same bed height, underflow concentration is lower during the bed descent phase compared to the continuous feeding phase. This study offers valuable insights for the precise control of underflow concentration in ultrafine tailing thickening processes.

The high-efficiency dewatering of ultra-fine tailings is one of the most prominent challenges in tailings thickening. The two-step shear flocculation process represents a promising practical method to achieve the dewatering of ultra-fine tailings. In this paper, a small self-made experimental device was used to simulate the two-step shear flocculation process of ultra-fine tailings, strengthening the effect of shear failure and shear coagulation, and we explored the mass fraction of ultra-fine tailings, floc structure size, floc strength, and regeneration performance of tailings slurry according to the variation in shear action in different stages. In addition, the synergistic mechanism of shear failure and shear coagulation in the two-step high-efficiency dewatering process of ultra-fine tailings was proposed. The results show that the dewatering of ultra-fine tailings was significantly improved by two-step flocculation, and the mass fraction of tailings can reach more than 71%. In the primary floc failure stage, the value of G₁T₁ should be higher than 100,000, and in the secondary floc regeneration stage, the value of G₂T₂ should be in the range of 7000~11,000. This paper provides a reference for the regulation of the shear mode and action range in the two-step flocculation process of ultra-fine tailings.