Metasilicic acid mineral water is a major functional drinking water resource with substantial health benefits. This study unveils the spatial distribution patterns and formation mechanisms of metasilicic acid groundwater hosted within granite, slate, and unconsolidated sedimentary aquifers in Pingjiang, Hunan Province, using hydrogeochemical and multi-isotope tracing methods. Results show that 43 % of granite fissure water, slate fissure water, and Quaternary pore water in the study area contain metasilicic acid contents that satisfy the standard of metasilicic acid mineral water. Among them, granite fissure water contains the highest metasilicic acid content, demonstrating its potential as a candidate for exploiting metasilicic acid mineral water. The metasilicic acid groundwater primarily receives recharge from atmospheric precipitation and belongs to the low-TDS (Total Dissolved Solids) HCO3-Ca(Mg) type. The metasilicic acid mainly originates from the hydrolysis of silicate minerals (e.g., plagioclase) within a carbonate medium. Soil CO2 and intense cation exchange serve as the primary drivers of dissolution. This study provides theoretical references for the exploration, development, and utilization of metasilicate acid mineral water resources within the same type of water-bearing rock group.
High-precision experimental technology and its theoretical development render bubble dynamics a vital research focus in mining engineering. Studies on bubble dynamics hold both theoretical and engineering significance and have yielded remarkable findings. This study therefore reviews bubble dynamics in flotation. Specifically, we introduced typical dynamic parameters and measurement methods such as bubble shape, rising velocity and motion trajectory, with emphasis on the advantages of applying high-speed camera in bubble dynamics measurement. We then discussed how major influencing factors such as bubble size, attached particles, flotation reagents and flow field environment affect bubble dynamics. We also reviewed the current research progress of bubble dynamics models, introduced the model of bubble deformation coefficient, bubble terminal velocity, and drag coefficient, while discussing the role of coupled models in numerical simulations for multiphase flow research. Since existing research primarily focused on idealized multiphase flow systems, investigating the dynamic characteristics of bubbles in actual multiphase flow environments would become a future direction, providing references for optimizing flotation processes.
This study addresses the long-distance and large-lift pipeline transportation of ultra-fine tailings paste by restoring the actual filling pipeline of the mine. We conducted numerical simulation using Fluent software to analyze the effect of speed and mass concentration on the paste pipeline transportation and elbow position. Results show that the paste filling slurry exhibited explicit velocity gradient in the radial direction, and the resistance loss of paste pipeline rose with increasing slurry flow rate. Comparatively, mass concentration exerted a major impact on pipeline resistance: as the concentration of filling slurry increased by 1%, resistance loss increased by 12%-15% on average; as the concentration exceeded 73%, resistance loss increased sharply, causing concentrated local pressure at the elbow and serious wearing of the pipeline. Therefore, for long-distance and large-lift pipeline transportation of ultrafine tailings paste, the suitable flow rate is 1.5-1.6 m/s, and the mass concentration should not exceed 73%. The reliability of these findings was confirmed through on-site industrial experiments and actual resistance monitoring.
The coordinated development of energy digitalization and greening (referred to as "dual transformation") is an essential pathway for optimizing energy systems through digital technologies to achieve high-quality development and carbon reduction in the context of climate change. Based on an in-depth analysis of the theoretical logic of coordinated energy dual transformation, this study constructed an indicator system to measure the progress of energy digitalization and greening. We employed the G1-entropy weight method and coupled coordination model to assess the coordinated development across 30 Chinese provinces from 2013 to 2022. Additionally, the study used the Dagum Gini coefficient, Kernel density estimation, and Markov chain model to analyze regional disparities and dynamic evolution. Results reveal that the coordinated development in energy dual transformation had been gradually improved, exhibiting a declining distribution pattern from eastern to central and western regions. The eastern and the central-western regions exhibited an explicit gap, and internal disparities within the eastern region showed a widening trend. On this account, this study proposed policy recommendations such as accelerating the development of key technologies and new infrastructure, establishing cross-regional and cross-departmental energy data-sharing platforms, and improving market-oriented incentive mechanisms. These suggestions aim to foster new quality productive forces and provide decision-making references for achieving high-quality energy development.
In-situ steam injection for oil shale exploitation (MTI) could significantly improve the in-situ pyrolysis efficiency of oil shale and enhance crude oil mobility. With Fushun oil shale as subject for analysis, this study proposes a thermal-hydraulic-mechanical (THM) coupling model containing a three-dimensional discrete fracture network via numerical simulation based on the Baecher disk model and the Fisher distribution to evaluate the actual pyrolysis effect through variations of the average reservoir temperature and the effective pyrolysis volume. Results show that, this MTI technology allowed 82.73 % of the oil shale reservoir to be pyrolyzed after 1.000 a of heat injection, with 13.33 % of energy loss reduction compared with that under the single heat-injection well mode. During heat injection, reservoir stress concentrated around the production wells, fracture intersections, and the top and bottom of the oil shale layer, with the maximum reservoir stress reaching 34.57 MPa. During pyrolysis, substantial settlement occurred around the heat injection wells, reaching 1.02 m after 1.000 a of continuous heat injection. As heat injection ceased, the elastic rebound of the formation recovered 16.0 % of the settlement loss. This study provides references for accurately evaluating the pyrolysis effect, ensuring the safety of mining engineering, and optimizing the heat-injection exploitation scheme in the large-scale implementation of MTI technology.
