Optimization model of unascertained measurement for underground mining method selection and its application

An optimization model of underground mining method selection was established on the basis of the unascertained measurement theory.Considering the geologic conditions,technology,economy and safety production,ten main factors influencing the selection of mining method were taken into account,and the comprehensive evaluation index system of mining method selection was constructed.The unascertained evaluation indices corresponding to the selected factors for the actual situation were solved both qualitatively and quantitatively.New measurement standards were constructed.Then,the unascertained measurement function of each evaluation index was established.The index weights of the factors were calculated by entropy theory,and credible degree recognition criteria were established according to the unascertained measurement theory.The results of mining method evaluation were obtained using the credible degree criteria,thus the best underground mining method was determined.Furthermore,this model was employed for the comprehensive evaluation and selection of the chosen standard mining methods in Xinli Gold Mine in Sanshandao of China.The results show that the relative superiority degrees of mining methods can be calculated using the unascertained measurement optimization model,so the optimal method can be easily determined.Meanwhile,the proposed method can take into account large amount of uncertain information in mining method selection,which can provide an effective way for selecting the optimal underground mining method.

Optimal mining sequence for coal faces under a bedding slope:insight from landslide prevention

Repetitive mining beneath bedding slopes is identified as a critical factor in geomorphic disturbances, especially landslides and surface subsidence. Prior research has largely concentrated on surface deformation in plains due to multi-seam coal mining and the instability of natural bedding slopes, yet the cumulative impact of different mining sequences on bedding slopes has been less explored. This study combines drone surveys and geological data to construct a comprehensive three-dimensional model of bedding slopes. Utilizing FLAC3D and PFC2D models, derived from laboratory experiments, it simulates stress, deformation, and failure dynamics of slopes under various mining sequences. Incorporating fractal dimension analysis, the research evaluates the stability of slopes in relation to different mining sequences. The findings reveal that mining in an upslope direction minimizes disruption to overlying strata. Initiating extraction from lower segments increases tensile-shear stress in coal pillar overburdens, resulting in greater creep deformation towards the downslope than when starting from upper segments, potentially leading to localized landslides and widespread creep deformation in mined-out areas. The downslope upward mining sequence exhibits the least fractal dimensions, indicating minimal disturbance to both strata and surface. While all five mining scenarios maintain good slope stability under normal conditions, recalibrated stability assessments based on fractal dimensions suggest that downslope upward mining offers the highest stability under rainfall, contrasting with the lower stability and potential instability risks of upslope downward mining. These insights are pivotal for mining operations and geological hazard mitigation in multi-seam coal exploitation on bedding slopes.

Monte Carlo Analytic Hierarchy Process (MAHP) approach to selection of optimum mining method

One of the most critical and complicated steps in mine design is a selection of suitable mining method based upon geological,geotechnical,geographical,safety and economical parameters.The aim of this study is developing a Monte Carlo simulation to selection the optimum mining method by using effective and major criteria and at the same time,taking subjective judgments of decision makers into consideration.Proposed approach is based on the combination of Monte Carlo simulation with conventional Analytic Hierarchy Process(AHP).Monte Carlo simulation is used to determine the confdence level of each alternative’s score,is calculated by AHP,with the respect to the variance of decision makers’opinion.The proposed method is applied for Jajarm Bauxite Mine in Iran and eventually the most appropriate mining methods for this mine are ranked.

Analysis of the Impact on Hydraulic Facilities Due to Underground Mining Based on the Influence Function Method

A mathematical model based on influence function method was established to predict the surface movement and deformation due to underground mining, and the impact on the upper hydraulic facilities in one coal mine was analyzed used the model. The analysis indicates: the maximum surface subsidence reaches 3.5 m, and the predicted maximum horizontal surface deformation reaches 7.0 mm/m, which would result in crack, deformation and uneven settlement in the soil foundation of the upper hydraulic facilities and influence the quality directly. Therefore, reasonable engineering measurements should be adopted to ensure the safe operation.

On the design and selection of vehicle coordination policies for underground mine production ramps

Traffic management in underground mines,especially on production ramps,is a difficult problem to optimize and control.Most operations use one of a few common policies;e.g.,the so-called ‘‘lock-out" and‘‘loaded-vehicle-priority" policies.The work presented in this paper uses discrete-event simulation to study the efficiency of multiple policies.Based on simulation results,an improvement to the common lock-out policy is proposed.This new policy utilizes the rules of the lock-out policy but integrates an option that allows a group of vehicles to be given temporary priority in a certain direction of travel.Quantitative results are provided and,based on these,a systematic technique for ramp design that aims to optimize the efficiency of underground mine ramp traffic flow is described.

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.

Safety analysis of Sormeh underground mine to improve sublevel stoping stability

In underground mines,sublevel stoping is used among a variety of different methods for mining an orebody,which creates large underground openings.In this case,the stability of these openings is affected by a number of factors,including the geometrical characteristics of the rock and mining-induced stresses.In this study,a sensitivity analysis was conducted with the numerical,squat pillar,and Mathews stability methods using the Taguchi technique to properly understand the influence of geometric parameters and stress on stope stability according to Sormeh underground mine data.The results show a full factorial analysis is more reliable since stope stability is a complex process.Furthermore,the numerical results indicate that overburden stress has the most impact on stope stability,followed by stope height.However,the results obtained with Mathews and squat pillar methods show that stope height has the greatest impact,followed by overburden stress and span.It appears that these methods overestimate the impact of stope height.Therefore,it is highly recommended that Mathews and squat pillar methods should not be used in high stope that is divided with several sill pillars.Nonetheless,Mathews method cannot accurately predict how the sill pillar impacts the stope stability.In addition,numerical analysis shows that all geometric parameters affect the roof safety factor,whereas the sill pillar has no significant influence on the safety factor of the hanging wall,which is primarily determined by the stope height–span ratio.

Optimum mining method selection using fuzzy analytical hierarchy process–Qapiliq salt mine,Iran

Mining method selection is the first and the most critical problem in mine design and depends on some parameters such as geotechnical and geological features and economic and geographic factors.In this paper,the factors affecting mining method selection are determined.These factors include shape,thickness,depth,slope,RMR and RSS of the orebody,RMR and RSS of the hanging wall and footwall.Then,the priorities of these factors are calculated.In order to calculate the priorities of factors and select the best mining method for Qapiliq salt mine,Iran,based on these priorities,fuzzy analytical hierarchy process(AHP) technique is used.For this purpose,a questionnaire was prepared and was given to the associated experts.Finally,after a comparison carried out based on the effective factors,between the four mining methods including area mining,room and pillar,cut and fill and stope and pillar methods,the stope and pillar mining method was selected as the most suitable method to this mine.

Deformation features and failure mechanism of steep rock slope under the mining activities and rainfall

Underground mining activities and rainfall have potential important influence on the initiation and reactivation of the slope deformations,especially on the steep rock slope. In this paper,using the discrete element method(UDEC),numerical simulation was carried out to investigate deformation features and the failure mechanism of the steep rock slope under mining activities and rainfall. A steep rock slope numerical model was created based on a case study at the Wulong area in Chongqing city,China. Mechanical parameters of the rock mass have been determined by situ measurements and laboratory measurements. A preliminary site monitoring system has been realized,aiming at getting structure movements and stresses of unstablerock masses at the most significant discontinuities. According to the numerical model calibrated based on the monitoring data,four types of operation conditions are designed to reveal the effect of mining excavation and extreme rainfall on the deformation of the steep rock slope.

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.

Mechanical performance of a double-face reinforced retaining wall in an area disturbed by mining

The application of a double-face reinforced retaining wall during road construction can reduce engineering costs, speed road paving and have a good influence on environment. An ABAQUS numerical model of a double-face reinforced retaining wall was built. The influence of surface subsidence induced by mining was considered. A physical model test was also performed in the laboratory on a reinforced retaining wall. The influence of subsidence induced by mining was observed. The numerical results match measurements in the laboratory very well. The vertical pressure on the base of the retaining wall, the horizontal displacement of the wall and the horizontal soil pressure acting on the wall were analyzed. The differential settlement of the reinforced belt and axial forces in the wall were also studied.

Evaluating performance of lignite pillars with 2D approximation techniques and 3D numerical analyses

This paper attempts to investigate the use of approximate 2D numerical simulation techniques for the evaluation of lignite pillar geomechanical response, formed via the room and pillar mining method.Performance and applicability of the developing methodology are assessed through benchmarking with a more direct and accurate 3D numerical model. This analysis utilizes an underground lignite mine which is being developed in soft rock environment. Through the decisions made for the optimum room and pillar layout, the design process highlights the strong points and the weaknesses of 2D finite element analysis, and provides useful recommendations for future reference. The interpretations of results demonstrate that 2D approximation techniques come near quite well to the actual 3D problem.However, external load approximation technique seems to fit even better with the respective outcomes from the 3D analyses.

深部采矿岩石力学进展

随着煤炭开采日益向深部发展,深部采矿引发的围岩大变形破坏和强冲击动力灾害日益严峻。在深部高地应力、高地温、高渗透压、强采动、强流变及多场耦合的复杂地质力学环境下,深部采场的应力场特征、煤岩体破碎性质、岩层移动及能量的积聚释放规律等均发生了显著变化。针对深部采矿中的岩石力学问题,论述了笔者及团队在深部采煤方法、深部巷道破坏机理与围岩控制、深井热害与地热利用三大方向取得的进展,主要包括:(1)提出了平衡开采理论和实现平衡开采的110/N00工法,进行了千米深井现场工程应用;(2)构建了深部“非均压建井”模式,研发了实现深井稳定提升的SAP系统,形成了可大幅简化井巷工程量和提高矿井采出率的建井方法;(3)研发了多套适用于研究深部岩体在水、高温、高压、结构效应及多场耦合作用下发生宏观破坏的实验系统和可进行微观层面演算的超算系统,揭示了深部软岩大变形破坏机理及多尺度力学特性;(4)研制了深部岩体冲击型和应变型岩爆实验系统,阐述了深部岩体冲击能量沿开挖临空面瞬间释放的非线性动力学行为;(5)提出了深部巷道开挖补偿支护理论,进一步发展了具有高恒阻、高延伸率、强吸能和耐冲击超常力学特性的NPR支护材料和技术;(6)研发了模拟深部高温、高湿和高压环境下的岩体热力学实验系统,提出了热害治理和热能资源化利用方法,建立了深部热害治理与热能综合利用系统(HEMS)。相关研究成果已在深部开采领域得以应用,可为深部采矿面临的复杂岩石力学问题提供借鉴。

A new evaluation method for site selection of large underground water-sealed petroleum storage depots

Scientific site selection is the first step in constructing underground water-sealed petroleum storage depots, but no uniform standard and code for such activity has been established. Therefore, the main objective of this study is to propose an evaluation method for the site selection of an underground water-sealed petroleum storage depot. The first large underground water-sealed petroleum storage depot being built in China served as the background of this study. The following 12 indexes were used as evaluation factors based on comprehensive evaluation criteria and specifications for key project site selection: geographic structure development feature, topographic feature, lithostratic formation feature, crustal stress, strength of rock mass, joint development feature, hydrogeological conditions, long-term water sealing conditions, environmental/ecological vulnerability, regional stability, technical and economic conditions, and meteorological and hydrological conditions. The weight back analysis and power coefficient methods were also used to evaluate the site selected for the first underground water-sealed petroleum storage depot project. Petroleum site classification models based on the two aforementioned methods were established and used to verify the feasibility of the evaluation criteria and methods, and the evaluation results show the grade of the site selected for the underground water-sealed petroleum storage depot in Huangdao, China is good. The study results may be used as a reference for the site selection of future underground water-sealed petroleum storage depots.

井工煤矿全生命周期甲烷捕集核算及减排路径

甲烷减排是我国碳减排目标的重要组成部分,建立甲烷捕集核算体系是实现甲烷减排的前提。以甲烷近零排放为目标,结合《国家温室气体清单指南:IPCC—2019》和煤炭企业温室气体排放核算国家标准,提出了井工煤矿全生命周期中地质勘探、煤炭开采、矿后活动和煤矿废弃各阶段甲烷捕集的具体核算方法,构建了井工煤矿全生命周期甲烷捕集核算模型。在此基础上,提出了井工煤矿甲烷减排路径及其实施方案。研究结果可为井工煤矿甲烷治理与低碳发展提供指导。

地下开采扰动对露天排土场边坡变形破坏的影响

为了研究地下开采对上覆露天矿排土场边坡变形破坏的影响规律,以酸刺沟煤矿及哈尔乌素露天矿排土场为研究对象,分析了地表沉陷规律及其诱发排土场变形破坏的机制,采用概率积分法对地表沉陷量进行了预测,并借助FLAC^(3D)软件分析排土场边坡变形及地表塌陷,同时分析了酸刺沟煤矿工作面回采结束后,哈尔乌素露天矿排土场的位移变化。结果表明:概率积分法预测最大沉陷量为21 m左右,模拟计算最大沉陷量为22 m左右;两者的地表最大沉陷量均随着开采阶段的进行先增大后逐渐趋于稳定,符合地表沉陷形成移动盆地的规律;数值模拟结果和实际塌陷区位置一致;排土场边坡水平位移量与工作面推进长度呈正相关;工作面走向上,采空区两侧水平位移最大,呈现出向采空区中部滑移的特征,且总体表现为左侧边坡水平位移大于右侧边坡。

某金属矿体充填开采对地表建(构)筑物稳定性的耦合评估

为研究某金属矿山地下开采对地表建(构)筑物稳定性影响,综合运用理论分析、三维精细化建模、数值模拟分析方法,提出了一种地表建(构)筑物稳定性评估的耦合方法。结果表明:采用充填法开采,地表整体为均匀沉降,对地表建(构)筑物的稳定性影响较小,最大主应力随回采步骤的增加呈多项式增长趋势,最小主应力呈线性增长;通过理论分析计算,矿区地表变形值及质点振速均小于相关规程要求的临界值;各塑性区范围均较小,充填开采可有效避免拉伸、剪切破坏区域进一步扩大;矿体回采使得矿体正上方地表呈锥状下沉,矿区地表变形值均远小于规范中的临界变形值。地下开采不会对地表建(构)筑物产生影响。

停车场出入场线暗挖区间施工技术

以某市环园中路停车场出入场线项目为背景,在停车场出入场线暗挖区间施工中,通过分析工程难点,采用杂填土层注浆加固、超前大管棚、暗挖区间矿山法、二次衬砌以及地基处理等关键技术,成功克服了杂填土段开挖和下穿商场等难题。工程实践结果表明,该施工方案高效、安全、可控。

浅谈井下采煤技术的合理选择

旨在探讨井下采煤技术的合理选择,以应对煤矿开采过程中的复杂挑战。首先介绍了井下采煤技术的多样性以及其在煤矿工程中的重要性。然后,通过对各种井下采煤技术的比较分析,深入探讨了它们的优劣势以及成本与效率的权衡。接着探讨了地质条件、安全与环保以及未来发展趋势等因素在井下采煤技术选择中的重要性。最后得出结论,强调了在井下采煤技术选择过程中综合考虑多方面因素的重要性,以实现最佳的工程效果。

煤矿井下采煤技术及方法

随着经济的发展,人们对煤炭资源的需求逐渐提升。煤矿企业应通过优化采煤技术及方法,保证开采质量和效率。对煤矿井下采煤的现状、特点及影响因素进行分析,重点围绕煤矿井下采煤技术及方法开展研究。