Stability and reliability of pit slopes in surface mining combined with underground mining in Tonglushan mine

Slope stability is of critical importance in the process of surface-underground mining combination. The influence of underground mining on pit slope stability was mainly discussed, and the self-stabilization of underground stopes was also studied. The random finite element method was used to analyze the probability of the rock mass stability degree of both pit slopes and underground stopes. Meanwhile, 3D elasto-plastic finite element method was used to research into the stress, strain and rock mass failure resulting from mining. The results of numerical simulation indicate that the mining of the underground test stope has certain influence on the stability of the pit slope, but the influence is not great. The safety factor of pit slope is decreased by 0.06, and the failure probability of the pit slope is increased by 1.84%. In addition, the strata yielding zone exists around the underground test stope. The results basically conform to the information coming from the field monitoring.

Reliability Theory Study of Combined Mining Technology System in Surface Mines

The connection between all the single systems iu combined technology is analysed, and the mine engineering reliability is calculated in any area of the mines using combined technololgy system. The reliability design and distribution method in this system is put forward, thus the basis is set for the decision to raise the total production capability or the surface mines in which the combined system is used.

Optimization principle of combined surface and underground mining and its applications

The pit limit optimization is discussed, which is one of the most important problems in the combined min-ing method, on the basis of the economic model of ore-blocks. A new principle of the limit optimization is put for-ward through analyzing the limitations of moving cone method under such conditions. With a view to recovering asmuch mineral resource as possible and making the maximum profit from the whole deposit, the new principle is tomaximize the sum of gain from both open-pit and underground mining. The mathematical models along the horizon-tal and vertical directions and modules for software package (DM&MCAD) have been developed and tested inTonglushan Copper Mine. It has been proved to be rather effective in the mining practice.

Heterogeneous information phase space reconstruction and stability prediction of filling body–surrounding rock combination

Traditional research believes that the filling body can effectively control stress concentration while ignoring the problems of unknown stability and the complex and changeable stress distribution of the filling body–surrounding rock combination under high-stress conditions.Current monitoring data processing methods cannot fully consider the complexity of monitoring objects,the diversity of monitoring methods,and the dynamics of monitoring data.To solve this problem,this paper proposes a phase space reconstruction and stability prediction method to process heterogeneous information of backfill–surrounding rock combinations.The three-dimensional monitoring system of a large-area filling body–surrounding rock combination in Longshou Mine was constructed by using drilling stress,multipoint displacement meter,and inclinometer.Varied information,such as the stress and displacement of the filling body–surrounding rock combination,was continuously obtained.Combined with the average mutual information method and the false nearest neighbor point method,the phase space of the heterogeneous information of the filling body–surrounding rock combination was then constructed.In this paper,the distance between the phase point and its nearest point was used as the index evaluation distance to evaluate the stability of the filling body–surrounding rock combination.The evaluated distances(ED)revealed a high sensitivity to the stability of the filling body–surrounding rock combination.The new method was then applied to calculate the time series of historically ED for 12 measuring points located at Longshou Mine.The moments of mutation in these time series were at least 3 months ahead of the roadway return dates.In the ED prediction experiments,the autoregressive integrated moving average model showed a higher prediction accuracy than the deep learning models(long short-term memory and Transformer).Furthermore,the root-mean-square error distribution of the prediction results peaked at 0.26,thus outperforming the no-prediction method in 70%of the cases.

Predicting coal mining faults using combined rock relationships

By studying different compressive strengths and changes in the characteristics of rocks,five variables were selected to predict faults in coal mines. Drillholes in the mined area were divided into two populations, i.e., drillholes containing faults and drillholes without faults. Discriminant functions were established from the values of the five variables using Fisher's approach. Drillholes in the non-mined areas were allocated to one of the two populations by using discriminant functions. The terrenes of each drillhole were divided into 10 sections, above and below a minable coal seam. Each section has 10 layers of rocks. The population to which each drillhole in a section belongs is sorted out and the probability of each drillhole with faults obtained,i.e., a contour map of predicting the probability of faults in coal mining is shown. A comparison with the real distribution of faults shows that the precision of accurately predicting faults is greater than 70 per cent.

STUDY ON THE SMALL CRACKS OF COVER STRATA AFTER THE COMBINED MINING IN THE THIN SEAMS

By using the continuous exploration system with multi-pipeline in the borehole, the failure cracks of cover strata (specially, the small cracks developing) after the combined mining of 16, 17 thin seams of the 4th mining block in Zhaopo Mine is explored. After that, the researching result is considered as the output and the testing result of rock mechanics parameters is considered as the verifying data, the back analysis is made with the conception of the point safety degree. The relative height of the crack developing is obtaied. So, the evaluating of the safety of 16, 17 seams combined mining under the gob water with extreme distance is made and the mining has been safety. The scientific basis is provided for the evaluating of the mining safety with the similar conditions.

Study on the Law of the Movement and Damage to Slope with the Combination of Underground Mining and Open-Pit Mining

Under circumstances in which both underground mining and open-pit mining are employed, the mining effects of two approaches will be superposed and the mining slope will receive several induced stress fields, which makes the sliding mechanism and deformation law of slope rock mass more complicated. This paper, targeting at the east slope of Antaibao Mine with the joint employment of underground mining and open-pit mining, aims to study the moving law of the slope rock mass and the damage mechanism to the overburden of the goaf by numerical simulation. It is supposed that models of possible damage to the slope could be explored for guidance to safety-production of the mine.

Reasonable location parameters of pick and nozzle in combined cutting system

The drum shearer and high pressure water jet combined cutting system is an effective technology to cut hard coal-rock, but one problem of the technology is the choice of pick and nozzle location parameters. In order to solve the problem, the process and mechanism of combined cutting are studied and mining seepage catastrophe theory is used to construct the mathematic and physical model of combined cutting hard coal-rock. Based on the model and detailed analysis of combined cutting mechanism, the single pick and nozzle combined cutting test-bed is built to test the main pick and nozzle location parameters of drum shearer and water jet combined cutting system. Test results show that the best vertical distance between the pick-tip and nozzle center point is the sum of cutting thickness and proper target distance in the Y axial direction; the best horizontal distance is the length between pick-tip point and coal-rock surface bursting crack point in the X axial direction. The best incident angle of water jet should be the same as the bursting crack line's angle in theory, but considering other important factors comprehensively, it is more reasonable when the incident angle of water jet is 90 °.

Poor awareness of preventing aspirin-induced gastrointestinal injury with combined protective medications

AIM:To investigate prescribing pattern in low-dose aspirin users and physician awareness of preventing aspirin-induced gastrointestinal(GI) injury with combined protective medications.METHODS:A retrospective drug utilization study was conducted in the 2nd Affiliated Hospital,School of Medicine,Zhejiang University.The hospital has 2300 beds and 2.5 million outpatient visits annually.Data mining was performed on all aspirin prescriptions for outpatients and emergency patients admitted in 2011.Concomitant use of proton-pump inhibitors(PPIs),histamine 2-receptor antagonists(H2RA) and mucoprotective drugs(MPs) were analyzed.A defined daily dose(DDD) methodology was applied to each MP.A further investigation was performed in aspirin users on combination use of GI injurious medicines [non-steoid anti-inflammatory drugs(NSAIDs),corticosteroids and clopidogrel and warfarin] or intestinal protective drugs(misoprostol,rebamipide,teprenone and gefarnate).Data of major bleeding episodes were derived from medical records and adverse drug reaction monitoring records.The annual incidence of major GI bleeding due to low-dose aspirin was estimated for outpatients.RESULTS:Prescriptions for aspirin users receiving PPIs,H2RA and MPs(n = 1039) accounted for only 3.46% of total aspirin prescriptions(n = 30 015).The ratios of coadministration of aspirin/PPI,aspirin/H2RA,aspirin/MP and aspirin/PPI/MP to the total aspirin prescriptions were 2.82%,0.12%,0.40% and 0.12%,respectively.No statistically significant difference was observed in age between patients not receiving any GI protective medications and patients receiving PPIs,H2RA or MPs.The combined medication of aspirin and PPI was used more frequently than that of aspirin and MPs(2.82% vs 0.40%,P < 0.05) and aspirin/H2RA(2.82% vs 0.12%,P < 0.05).The values of DDDs of MPs in descending order were as follows:gefarnate,hydrotalcite > teprenone > sucralfate oral suspension > L-glutamine and sodium gualenate granules > rebamipide > sucralfate chewable tablets.The ratio of MP plus aspirin prescriptions to the total MP prescriptions was as follows:rebamipide(0.47%),teprenone(0.91%),L-glutamine and sodium gualenate granules(0.92%),gefarnate(0.31%),hydrotalcite(1.00%) and sucralfate oral suspension(0.13%).Percentages of prescriptions containing aspirin and intestinal protective drugs among the total aspirin prescriptions were:rebamipide(0.010%),PPI/rebamipide(0.027%),teprenone(0.11%),PPI/teprenone(0.037%),gefarnate(0.017%),and PPI/gefarnate(0.013%).No prescriptions were found containing coadministration of aspirin and other NSAIDs.Among the 3196 prescriptions containing aspirin/clopidogrel,3088(96.6%) prescriptions did not contain any GI protective medicines.Of the 389 prescriptions containing aspirin/corticosteroids,236(60.7%) contained no GI protective medicines.None of the prescriptions using aspirin/warfarin(n = 22) contained GI protective medicines.Thirty-five patients were admitted to this hospital in 2011 because of acute hemorrhage of upper digestive tract induced by low-dose aspirin.The annual incidence rates of major GI bleeding were estimated at 0.25% for outpatients taking aspirin and 0.5% for outpatients taking aspirin/warfarin,respectively.CONCLUSION:The prescribing pattern of low-dose aspirin revealed a poor awareness of preventing GI injury with combined protective medications.Actions should be taken to address this issue.

Modular Combination Design of Mine Rescue Capsule Based on Load Simulation

Mine rescue capsule is a typical emergency equipment in a coal mine.It provides a safe and confined space for miners when mining disasters occurred.The length of the passenger survival cell is suitable to be adjusted with several predefined modular cells according to various numbers of passengers.Aiming at the shortage of guidance rules for the modular combination design of mine rescue capsule,the configuration situations of survival cells are experimented with static and impact load analysis in ANSYS Workbench.The length range of a single cell,the combination schemes of miner survival section,and the effectiveness proof of assembled rescue capsules were solved sequentially by simulated load analysis on constructed structural models.The modular combination rules of the survival section are developed for variant passenger number ranging from 8 to 20.It also provides a reference for the optimal selection of rescue capsules with the same capacity.The proposed modular rules are effective for the rapid configuration design for mine rescue capsule driven by the number of passengers.

煤矿井下掘进机器人路径规划方法研究

针对煤矿非全断面巷道条件下掘进机器人移机难度大、效率低下等问题,分析了煤矿井下非结构化环境特征及掘进机器人运动特性,提出了基于深度强化学习的掘进机器人机身路径规划方法。利用深度相机将巷道环境实时重建,在虚拟环境中建立掘进机器人与巷道环境的碰撞检测模型,并使用层次包围盒法进行虚拟环境碰撞检测,形成巷道边界受限下的避障策略。考虑到掘进机器人形体大小且路径规划过程目标单一,在传统SAC算法的基础上引入后见经验回放技术,提出HER-SAC算法,该算法通过环境初始目标得到的轨迹扩展目标子集,以增加训练样本、提高训练速度。在此基础上,基于奖惩机制建立智能体,根据掘进机器人运动特性定义其状态空间与动作空间,在同一场景下分别使用3种算法对智能体进行训练,综合平均奖励值、最高奖励值、达到最高奖励值的步数以及鲁棒性4项性能指标进行对比分析。为进一步验证所提方法的可靠性,采用虚实结合的方式,通过调整目标位置设置2种实验场景进行掘进机器人的路径规划,并将传统SAC算法和HER-SAC算法的路径结果进行对比。结果表明:相较于PPO算法和SAC算法,HER-SAC算法收敛速度更快、综合性能达到最优;在2种实验场景下,HER-SAC算法相比传统SAC算法规划出的路径更加平滑、路径长度更短、路径终点与目标位置的误差在3.53 cm以内,能够有效地完成移机路径规划任务。该方法为煤矿掘进机器人的自主移机控制奠定了理论基础,为煤矿掘进设备自动化提供了新方法。

基于组合赋权三维云评估技术的深部煤矿顶板事故风险分析

为了更好地对深部煤矿顶板事故展开风险评价,提出了组合赋权三维云评估技术。基于事故统计及事故致因理论,对深部煤矿顶板事故风险指标体系展开研究,采用博弈论对改进层次分析法(Analytic Hierarchy Process,AHP)和熵权法进行博弈分析,以实现风险指标的组合赋权,通过构建三维云模型,对深部煤矿顶板事故危险性进行可视化分析。结果表明:包括行为、技术、设备、环境、管理5大风险因素在内的一级指标并其下20个二级风险指标是深部煤矿顶板事故风险评价指标体系的主体内容,且以环境风险权重最大;由三维云评估技术分析可知,平煤九矿的顶板事故风险级别为Ⅲ级,即修复后可接受,与该矿生产实际情况相符。组合赋权三维云评估技术的提出有助于完善深部煤矿顶板事故风险评价方法,可应用于工程实践。

基于上覆岩层应力场和裂缝场演化的采动井套管破断特征及防控对策

准确确定出煤矿采动井套管破断特征并提出相应的防控对策,能为井筒长期稳定提供重要保障。以平顶山矿区的二1煤层及上覆岩层为研究对象,采用理论计算与数值模拟软件模拟方法,确定出上覆岩层离层段应力和位移分布规律,分析了上覆岩层高度、距工作面水平距离与应力、位移的相关性,拟合出上覆岩层高度、距工作面水平距离与应力、位移的关系式;根据研究区采动井的实际开发经验,确定出最佳布井区域下的套管主要破断类型,结合常用套管力学参数,得出“两场”演化下的套管破断位置及长度等特征;对常用的采动井局部防护技术进行总结,并提出对应的防控对策。结果表明:工作面推进过程中,上覆岩层应力呈现出“波动-线性降低”的变化规律,位移呈现出“几乎未发生变化-类双曲线型”的变化规律。最佳布井区域下的采动井套管主要以拉伸缩径和剪切破断为主,选择施加套管加强件对采动井套管进行加固。研究区地面采动井三开段采用N80套管时,需在煤层上部46 m亚关键层处、54 m软硬互层处分别加设抗拉伸套管加强件和抗剪切加强件;采用P110套管时,需在煤层上部46 m亚关键层处加设抗拉伸加强件。建议研究区地面采动井三开段均采用P110套管,增加采动井的井筒稳定性。该研究成果为平顶山矿区及相似条件下采动井预防套管破断提供了理论指导。

融合多源数据挖掘信息的非轴对称端壁/叶身联合成型设计空间知识挖掘

为厘清联合成型设计空间各造型方法对涡轮叶栅性能提升的贡献,将基于总变差分析的全局敏感性分析方法与平行坐标系及直方图、散点图等可视化技术相结合,提出了将多源数据挖掘信息进行融合的设计空间知识挖掘框架,并利用该框架对某小展弦比叶栅端壁/叶身联合成型设计空间进行知识挖掘。结果表明:叶栅气动损失增减对基元型线微调十分敏感;非轴对称端壁所带来的损失减少量与型线微调接近,但设计空间内不同非轴对称端壁样本性能波动较小,导致其重要性被全局敏感性分析方法低估;虽然单独采用弯叶片难以整体降低小展弦比叶栅损失,但将弯、型线微调和非轴对称端壁造型相结合可获得“1+1+1>3”的性能增益;在端壁/叶身联合成型设计空间内,将基元型线朝着后加载方向微调,并采用喉部附近下凹较深的非轴对称端壁造型及反弯叶片设计,可获得气动损失较小的叶栅设计。研究结果明晰了端壁/叶身联合成型设计空间优化解特征,可为类似小展弦比叶栅设计优化提供借鉴。

M-CM-GA-BP算法的地表移动变形参数预测模型

针对复杂的开采沉陷预测问题,研究22个工作面采动地表移动变形参数变化规律,提出了一种基于M-CM-GA-BP算法求取地表移动变形参数的预测模型。通过线性加权组合预测方法和遗传算法优化BP神经网络的权值和阈值,融合多元回归模型来提高地表移动变形参数的求取精度,以地表下沉系数q为例,将该模型与其他预测模型预测性能进行对比分析,验证模型的准确性。结果表明,该模型能够有效地提高地表移动变形参数的预测精度,模型的平均相对误差为1.294、均方根误差为0.013,为地表移动变形参数预测提供了一种可行方法。

某钨矿露地联采关键地压灾害监测预警研究

某钨矿形成了露地联采的开采局面,面临着井下群采空区与隔离间柱稳定性、露采边坡稳定性、露地相互影响等关键地压灾害问题。设计建设了最先进的66通道微震监测系统、测量机器人与边坡雷达等地压监测预警系统。文章详细介绍了一次典型的岩体失稳垮塌的成功预警案例。上述综合性的地压监测手段将为矿山安全生产提供重要的技术支撑。

废弃矿山环境修复工作系统探讨

废弃矿山环境修复是还自然环境“历史旧账”的过程,是环境保护的一项至关重要的工作,该工作涉及领域广泛、投入资金量大、修复时间长、工作任务艰巨。为了优化废弃矿山环境修复工作方式,确保该项工作能够有序高效进行,首先,总结以往废弃矿山环境修复模式在构建过程中的不足之处,包括模式选定流程的缺乏和模式相对应技术的不明确;其次,建立一套能够快速且准确构建的修复模式,并且根据修复模式准确锁定修复技术的工作系统,该工作系统是以矿山的实际环境情况和矿山环境修复基本原则为基础、以修复目标为导向、以修复模式为框架、以修复技术为手段的优化组合;最后,以甘肃省定西市岷县某金矿历史遗留矿山的环境修复工程为实例,分析该工作系统对于废弃矿山环境修复工作的效果。废弃矿山环境修复工作系统的合理性与科学性对建成“绿水青山”的生态环境目标和“可持续发展”的经济建设目标有着深远的影响。

大红山铁矿露天——地下联合开采岩移发展规律研究

地下开采产生的地表移动会影响邻近露天采场边坡的稳定性。以大红山铁矿露天—地下联合开采为例,采用微震、地表开裂观测等多种方法进行岩移监测和数据分析,探究了地下开采引起的岩体移动与地表开裂规律。首先,对历史监测数据进行了整理和分析,包括地表塌陷和裂缝的发育情况。其次,针对地下开采过程中的围岩变形特点,开展微震数据分析,获取了岩体损伤破坏信息。同时,结合矿山地质资料,统计数据得出了陷落角的变化范围。结果表明:大红山铁矿露天—地下联合开采,岩体移动发展阶段可划分为:冒落及地表贯通的岩移阶段、陷落区充分发展的岩移阶段、F2断层影响的陷落角非对称发育阶段、废石充填与深部开采下的岩移阶段。西北部陷落角发育范围为75°~81°、东南部陷落角发育范围为65°~82°。研究可为类似地质及工程条件矿山岩移发展规律分析提供一定参考。

基于组合赋权-模糊评价法的绿色矿山建设评价

为解决目前绿色矿山采用直接赋分法存在缺乏客观性的难题,首先从资源、环境、社会、经济4方面选取了20项指标构建评价指标体系;其次以IAHP、CRITIC法及模糊综合评价法为理论基础,建立优化组合赋权-模糊综合评价模型;最后以陕西某矿山进行实例分析。结果表明,该矿山的总体绿色矿山建设已达到优秀水平,与实际建设情况相符。模型在兼顾主客观的同时,能充分利用指标信息,客观评价绿色矿山建设水平,可丰富和发展绿色矿山评价理论方法。

基于数据挖掘对中医药治疗CKD合并脑卒中的组方用药分析

基于数据挖掘方法探讨中医药治疗慢性肾脏病(CKD)合并脑卒中(CS)的临床用药规律。收集2017年10月至2022年10月天津中医药大学第一附属医院门诊治疗CKD合并CS的处方,建立中药处方数据库。统计分析用药频次、性味及归经,对处方中的药物进行聚类分析,利用SPSS Modeler 18 Apriori算法对所有药物进行关联分析。最终纳入544个处方,涉及中药258味,总用药频次8 886次。药性以寒性、温性、平性居多;药味以苦味、甘味、辛味为主;归经多为脾经、肝经;得出13个关联组合药对和5个核心药物组合。中医药对CKD合并CS患者的治疗,根据气虚血瘀、脾肾两虚的病机特点,主要采用健脾益气、补肾活血的组方用药。