Research and Application Status and Development Trend of Alkali-Activated Binder Powder for Mine Backfill

To improve the economic and social benefits of mining and backfill,it is necessary to find the backfill materials suitable for mineral mining,improve the various properties of the filling materials,and develop low cost,high performance new filling materials.Portland cement is neither environmentally friendly nor economical.Currently,we have begun to study and apply some industrial waste,such as slag,fly ash,and other solid wastes,with certain activities as the primary component of cementing material that will not only meet the technical requirements of filling,but also comprehensively utilize industrial waste and possess a benign,sustainable lifecycle for environmental protection.This study expounds the composition and reaction mechanism of alkali-activated binder powder used for cemented paste backfill material,summarizes the research and application status of alkaliactivated binder powders,including mechanics,durability,economic and environmental,and discusses future development directions for mine binder powders.It needs to continue to expand the utilization range of solid waste and improve the utilization rate of solid waste in the future.The development and research of this binder powder plays an important role in the progress of filling technologies.Hence,the research about alkali-activated binder powder contains great development potential and broad prospects.

Detecting the backfill pipeline blockage and leakage through an LSTM-based deep learning model

Detecting a pipeline's abnormal status,which is typically a blockage and leakage accident,is important for the continuity and safety of mine backfill.The pipeline system for gravity-transport high-density backfill(GHB)is complex.Specifically designed,efficient,and accurate abnormal pipeline detection methods for GHB are rare.This work presents a long short-term memory-based deep learning(LSTM-DL)model for GHB pipeline blockage and leakage diagnosis.First,an industrial pipeline monitoring system was introduced using pressure and flow sensors.Second,blockage and leakage field experiments were designed to solve the problem of negative sample deficiency.The pipeline's statistical characteristics with different working statuses were analyzed to show their complexity.Third,the architecture of the LSTM-DL model was elaborated on and evaluated.Finally,the LSTM-DL model was compared with state-of-the-art(SOTA)learning algorithms.The results show that the backfilling cycle comprises multiple working phases and is intermittent.Although pressure and flow signals fluctuate stably in a normal cycle,their values are diverse in different cycles.Plugging causes a sudden change in interval signal features;leakage results in long variation duration and a wide fluctuation range.Among the SOTA models,the LSTM-DL model has the highest detection accuracy of98.31%for all states and the lowest misjudgment or false positive rate of 3.21%for blockage and leakage states.The proposed model can accurately recognize various pipeline statuses of complex GHB systems.

膏体充填条带开采技术

为了解决煤矿采空区全部充填开采成本相对偏高的问题,同时有效地控制煤矿开采地表沉陷和保证承压水上采煤的安全性,提出了煤矿膏体充填的条带开采技术,该技术以煤层顶板(关键层)、受承压水影响的底板极限垮落步距和条带煤柱留设的理论为原则,设计了膏体条带充填的充填宽度和留设宽度,并对影响条带充填体稳定的充填体尺寸、物料的配比、充填体空间的围岩岩性、地质构造和充填体侧向应力等因素进行分析。理论分析证明该技术构成的"煤层底板—充填条带—上覆岩层—主关键层"的结构体系能够有效控制地表下沉和减少底板破坏深度,达到承压水上建(构)筑下安全采煤的需求并最大程度地减少充填开采成本。

影响中深部充填质量的因素探讨及对策

金川二矿区是我国最大的充填法开采的大型铜镍矿,年产矿石突破400万t,其开采深度超过千米,随着开采深度的加深,矿区地压日益明显,充填质量的好坏直接影响到矿山的安全生产。本文介绍了金川二矿区深部开采的矿区应力状况,探讨了充填材料、充填材料制备及采场充填工艺对充填质量的影响,并研究了保证充填质量的策略,对矿山中深部开采具有一定的借鉴。

基于弹性地基梁理论的端面顶板稳定性分析

端面冒顶一直是影响工作面安全高效开采的一大技术难题。采用弹性地基梁理论建立了端面顶板挠度微分方程,并运用PHASE 2D有限元软件建立了端面顶板稳定性数值模型,获得了煤层埋深、支架刚度、煤体刚度等因素对充填开采工作面端面顶板稳定性的影响。研究结果表明:采深越大或液压支架刚度越小,端面顶板下沉越明显;煤层地基系数或顶板弹性模量增大时,端面顶板下沉有所减小,但影响较为有限;从可行性考虑,提高液压支架刚度,可以有效控制工作面顶板变形,降低端面冒顶及煤壁片帮的风险。煤层埋深从200 m增加至250、300 m时,工作面前方塑性区宽度及支承压力显著增大,直接顶最大下沉量分别为61、78、96 mm。煤层弹性模量从2500 MPa增大至3500、4500 MPa时,工作面前方支承压力峰值略微增大,工作面前方煤体塑性区宽度也略微增大;直接顶下沉量略微减小。现场观测表明,充填开采条件下支架阻力较小,工作面区域矿压显现不明显,顶板下沉得到有效控制。