Using deep neural networks coupled with principal component analysis for ore production forecasting at open-pit mines

Ore production is usually affected by multiple influencing inputs at open-pit mines.Nevertheless,the complex nonlinear relationships between these inputs and ore production remain unclear.This becomes even more challenging when training data(e.g.truck haulage information and weather conditions)are massive.In machine learning(ML)algorithms,deep neural network(DNN)is a superior method for processing nonlinear and massive data by adjusting the amount of neurons and hidden layers.This study adopted DNN to forecast ore production using truck haulage information and weather conditions at open-pit mines as training data.Before the prediction models were built,principal component analysis(PCA)was employed to reduce the data dimensionality and eliminate the multicollinearity among highly correlated input variables.To verify the superiority of DNN,three ANNs containing only one hidden layer and six traditional ML models were established as benchmark models.The DNN model with multiple hidden layers performed better than the ANN models with a single hidden layer.The DNN model outperformed the extensively applied benchmark models in predicting ore production.This can provide engineers and researchers with an accurate method to forecast ore production,which helps make sound budgetary decisions and mine planning at open-pit mines.

Solution to the Horizontal Crossing Problem of Transportation System at Key Points in Open-Pit Mines

In order to reduce the horizontal crossing transportation problems between coal trucks and stripping trucks,large and small vehicles,and transport trucks and belt conveyors at key points of open pit mine in production,the separate transportation mode of underpass bridge and overpass steel trestle is proposed to optimize the open pit development transportation system,so as to solve the practical problems that the horizontal cross of transport vehicles causes vehicle blockage,affects production schedule and production safety.The results show that the horizontal crossing road can be changed into a separate type of overpass steel trestle,which can realize the classified transportation of large and small vehicles,reduce the traffic density,make vehicles with different functions go their own way,eliminate the hidden danger of traffic accidents,and improve the production efficiency.

Cut slope reinforcement technique in open-pit mines

The design and practice in supporting the cut slope of an open-pit mine wereintroduced, in which the high pressure grouting method was used in reinforcing the weak formation inthe slopes. Based on a detailed geological survey of the slope, a theoretical analysis was carriedout, and the design parameters were proposed, where the Tresca or Mohr-Coulomb yield criteria wasemployed. A patent technology, named 'Technology of high pressure and multiple grouting in differentlevels within a single hole', was employed in the construction. Anchor bars were also installed asgrouting proceeds. This method combines anchoring and grouting comprehensively and was foundsuccessful in practice.

Stability analysis of rib pillars in highwall mining under dynamic and static loads in open‑pit coal mine

The retained coal in the end slope of an open-pit mine can be mined by the highwall mining techniques.However,the instability mechanism of the reserved rib pillar under dynamic loads of mining haul trucks and static loads of the overlying strata is not clear,which restricts the safe and efcient application of highwall mining.In this study,the load-bearing model of the rib pillar in highwall mining was established,the cusp catastrophe theory and the safety coefcient of the rib pillar were considered,and the criterion equations of the rib pillar stability were proposed.Based on the limit equilibrium theory,the limit stress of the rib pillar was analyzed,and the calculation equations of plastic zone width of the rib pillar in highwall mining were obtained.Based on the Winkler foundation beam theory,the elastic foundation beam model composed of the rib pillar and roof under the highwall mining was established,and the calculation equations for the compression of the rib pillar under dynamic and static loads were developed.The results showed that with the increase of the rib pillar width,the total compression of the rib pillar under dynamic and static loads decreases nonlinearly,and the compression of the rib pillar caused by static loads of the overlying strata and trucks has a decisive role.Numerical simulation and theoretical calculation were also performed in this study.In the numerical simulation,the coal seam with a buried depth of 122 m and a thickness of 3 m is mined by highwall mining techniques.According to the established rib pillar instability model of the highwall mining system,it is found that when the mining opening width is 3 m,the reasonable width of the rib pillar is at least 1.3 m,and the safety factor of the rib pillar is 1.3.The numerical simulation results are in good agreement with the results of theoretical calculation,which verifes the feasibility of the theoretical analysis of the rib pillar stability.This research provides a reference for the stability analysis of rib pillars under highwall mining.

Circle geometric constraint model for open-pit mine ore-matching and its applications

The circle geometric constraint model （CGCM） was put forward for resolving the open-pit mine ore-matching problems （OMOMP）. By adopting the approaches of graph theory, block model of blasted piles was abstracted into a set of nodes and directed edges, which were connected together with other nodes in the range of circle constraints, to describe the mining sequence. Also, the constructing method of CGCM was introduced in detail. The algorithm of CGCM has been realized in the DIM1NE system, and applied to a short-term （5 d） program calculation for ore-matching of a cement limestone mine in Hebei Province, China. The applications show that CGCM can well describe the mining sequence of ore blocks and its mining geometric constraints in the process of mining blasted piles. This model, which is applicable for resolving OMOMP under complicated geometric constraints with accurate results, provides effective ways to solve the problems of open-pit ore-matching.

Numerical simulation study of the influence on stability of slope by underground mining under opencast coal mine slope

In view of the study on mining transferred from open-pit to underground, the research on the problem of the stabil- ity of slope is less. This article combined the actual situation of the Gaohai Coal Mine in Fuxin City and set up a three-dimensional model of the part of Huizhou open-pit slope by the finite difference software. Through the three-dimensional numerical simulation study of the influence on the stability of slope by underground mining, the basic characteristics of the open-pit slope deformation and the situation of basic stability were discussed. The simulation results of the mining slope of the displacement and deformation analysis of the state for mining provide a reference to the slope stability research.

Failure characteristics and its influencing factors of talus-derived rock mass during open-pit mining

The failure characteristic of talus-derived rock mass continues to challenge quantitative hazard assessments in open-pit mining. Physical model test was used to assess the failure modes and mechanisms on talus-derived rock mass. The different types of failure modes of the talus-derived rock mass were introduced and a possible failure mechanism relation between the failure zone and the structure of the talus-derived rock mass was also shown. The physical model test results indicate that the rainfall has significant influence on the stability and failure modes of talus-derived rock mass during open-pit mining. The development of the seepage area caused by rainfall initiates the localized failure in that particular area, and the initiation of localized instability is mainly induced by stress changes concentrated in the seepage area.

Application of open-pit and underground mining technology for residual coal of end slopes

Given the conditions of residual coal from the boundary of a flat dipping open-pit mine,which uses strip areas mining and inner dumping with slope-covering,we propose an open-pit and underground integrated mining technology for residual coal of end slopes.In the proposal a conveyance road and ventilation conveyance near the slope are built,corresponding to the pit mining area and the surface coal mine dump,as well as an interval haulage tunnel and air-inlet tunnel.The outcome shows that such mining method may reduce the effect to slope stability from underground mining,it does not affect the dumping advance and has a high recovery rate of residual coal resources.The working face is timbered by single hydraulic props,transported by a scraper conveyor and supported by coal walls.This method of mining is one of layered top coal caving,with high resource recovery,low production cost where positive economic benefit can be realized.

Evaluation of stress-control layout at the Subtropolis Mine,Petersburg,Ohio

The Subtropolis room-and-pillar mine extracts the Vanport Limestone(Allegheny Formation,Pennsylvanian System)near Petersburg,Ohio.Strata instability problems associated with excessive concentrations of lateral stress caused the mine operator to implement a change in layout design.This mining method has been identified as a stress control layout and has been used by other underground stone mines in the past with varying degrees of success.Practical experience has shown that entry headings advance in the direction of the principal lateral stress,producing lower stress concentrations with better mining conditions.It is important to minimize stress concentrations along the mining front,so an arrowshaped advance is recommended.This technique advances more developments(headings)in a"good"direction and reduces developments(crosscuts)in the"bad direction."As is expected,the stress control layout enhances the potential for shear failures in crosscuts.It is,therefore,important to focus crosscut engineering interventions that either:(a)lower stress concentrations(for example,an arched roof)or(b)enhance strength of the strata containing the shears(for example,rock reinforcement).This study focuses on observing strata conditions on a regular basis and monitoring the response of these strata to changing geologic and mining conditions through 3D Dynamic LiDAR scans.

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.

3DMine矿业平台与传统几何法的资源量估算对比分析——以南宁孔周山建筑石料用灰岩矿为例

以南宁市孔周山建筑石料用灰岩矿为例,介绍了3DMine矿业平台在建筑用砂石矿山资源量估算中的应用,并将3DMine与传统几何法两者的资源量估算结果进行对比分析。结果表明:传统几何法与3DMine(建模)法计算出的矿产资源量误差范围内一致,3DMine相比于传统几何法资源量估算精度更高,更能胜任矿体形态复杂条件下的资源量估算工作,同时3DMine能同步对接无人机的测量数据,更方便、快捷、动态地估算资源量。

A case study on the efficacy of different roof bolting schemes in Lhoist North America’s Crab Orchard Mine

Roof bolting has long been used in underground mines across the world to provide ground support.Modern roof bolts are cheap and easy to install with the use of specialized machines as a part of the production cycle. Lhoist North America’s Crab Orchard Mine is an underground room and pillar limestone mine that uses mechanically anchored roof bolts for ground support. The mine currently employs two different roof bolting patterns: a standard 1.5 × 1.5 m pattern, and another 0.8 × 0.8 m pattern for use in areas with particularly hazardous roof conditions. The purpose of this study is to evaluate the relative effectiveness of each bolting pattern. A series of numerical models were created using Roc Science’s RS2. The models were based on a symmetrical section of the mine at its deepest point, and were modeled using generalized Hoek-Brown failure criterion along with a discrete fracture network. A series of sensitivity analyses were performed on the models by varying parameters such as joint friction angle, crack persistence, joint randomization, and tensile strength of the limestone. Based on the results of the original models and sensitivity analyses, it appeared that the standard bolting pattern provided sufficient roof support capacity under almost all the expected conditions at the mine, since safety factors below the design value of 1.5 were only found for individual bolts in a few of the worst test cases considered.These results can help improve the mine’s productivity and reduce operating costs without compromising safety.

Numerical scheme for elastoplastic parameter identification and finite element analysis of wall-slope of the Fushun West Open Pit Mine

The elasto brittle plastic finite element analysis has been taken on the prediction for the deformation of the northwall of an open pit of Fushun, China. Numerical simulation has been made on the reinforcement measures of the slope structure. Using parameter identification techniques and connecting with elasto brittle plastic finite element program, the displacement back analysis has been made on the material parameters of the rockslope. The equivalent parameter values of the real slope structure have been obtained. The process of the rapid increment of the slope′s deformation caused by open mining during 1987～1990 has been reappeared through the numerical simulation.

3DMine软件在某建筑石料矿中的应用

为适应建筑石料矿山数字化、可视化发展趋势,提高矿山企业管理水平,应用3DMine矿业工程软件解决矿山三维展现、开采设计及日常管理中遇到的问题。以某建筑石料矿为例,通过收集整理地质勘探工程数据,应用3DMine软件建立地表模型、矿体模型、块体模型,在此基础上进行开采境界优化、采掘进度计划编制以及运矿道路布置等设计工作,探讨矿石价格变动与可采矿量、剥采比之间的关系,为类似矿山的开采设计、三维可视化管理提供一定借鉴。

Guidance and review:Advancing mining technology for enhanced production and supply of strategic minerals in China

Mineral resources,often referred to as“industrial food,”play a pivotal role in the national economic construction sector.Specifically,strategic minerals(SMs)bear a direct influence on the development of emerging strategic industries within China.This paper aims to shed light on the supply and demand dynamics,current status,and characteristics of SMs from the perspective of China's national security.We offer a comprehensive review of the current status and challenges associated with SM mining technology in China.Our analysis spans various mining methods,including open-pit mining,deep underground mining,green mining of complex underground bodies,integrated underground mining and processing,and intelligent mining.Within this framework,we delve into multiple initiatives aimed at improving the status of the mining industry,increasing production,and maintaining the adequate supply of these resources.We discuss these strategies from both a top-level policy and system design perspective,as well as detailed implementation plans.

Occupational risk assessment based on employees’ knowledge and awareness of hazards in mining

Analyses and assessments of hazards occurring in work processes are carried out by teams,in which there is usually one representative of the personnel,as the embodiment of the active participation of employees in the assessment of occupational risks.This is why the article presents research on all employees’knowledge and awareness about risks in their work environment.The research was carried out in the form of an employee survey in one of the open-pit mines,at workstations dealing with the loading and transporting of excavated material.The survey included a list of 40 hazards divided into four groups:(1)hazards related to machines and equipment used,(2)hazards related to exposure,(3)hazards with an impact extending beyond the workstation and(4)hazards of an ergonomic nuisance nature,where employees were required to indicate which hazards apply to their workplaces and determine their level of signifcance,probability of occurrence and the scale of possible efects.In this way,a hierarchical identifcation of threats occurring at the analyzed workplaces was made,and the obtained results were used to determine the amount of occupational risk both for specifc workstations and for the whole technological process.The measures of the magnitude of occupational risk obtained using the proposed method have showed that,according to the respondents,greatest risks at the workstation are associated with moving machines and vehicles and with mobile equipment.Equally important risks,which were often mentioned by employees,were those directly related to their health,i.e.,related to ergonomic nuisance and exposure.Threats resulting from geological and mining conditions,considered typical for mining,were important for the surveyed miners but they were not the most important owing to proper prevention,good organization of work and high safety culture The active involvement of the crew in the process of assessing occupational hazards allowed to identify the signifcance of each hazard,in the opinion of the personnel working at various places and to use this ranking for determining occupational risk levels in the mining company concerned.The research has also outlined another goal to be achieved:a comparison of the relative signifcance of hazards identifed by the employees and of the hazards listed in occupational risk assessment matrices used by mines.

Web pillar stability in open‑pit highwall mining

When highwall mining technology is applied to recover large amounts of residual coal left under the highwall of a big openpit mine,a reasonable coal pillar width is required to ensure the stability of the web pillars.Using numerical simulations,this paper studied the characteristics of the abutment stress distribution in the web pillars under different slope angles and mining depths,and established a relation describing the stress distribution in the web pillar.The relationship between the abutment stress and the ultimate strength of the web pillar under different pillar widths was also analyzed.In combination with the failure characteristics of the pillar yield zone,this relationship was used to explore the instability mechanism of web pillars.Finally,the optimal retaining widths of the web pillars were determined.Based on the modeling results,a mechanical bearing model of the web pillar was established and a cusp catastrophe model of pillar-overburden was constructed.Additionally,the web pillar instability criterion was derived.By analyzing the ultimate strength of the web pillars,a formula for calculating the yield zone width either side of the pillars was established.Using the instability criterion of web pillars in highwall mining,a reasonable pillar width can be deduced theoretically,providing significant guidance on the application of highwall mining technology.

陕西紫阳某废弃石煤矿酸性废水的产生机理探讨

在自然环境中,黄铁矿容易发生氧化反应导致酸性矿山废水(AMD)污染,进而威胁人类的健康安全。石煤及矸石中伴生的黄铁矿及重金属(镉、镍、钒、锰、锌等)成分复杂,经大气降雨、地表水以及基岩裂隙水的长期浸泡淋溶,产生酸性水,加剧有毒有害重金属元素浸出。AMD因产量大、形成时间跨度长、产源地分散等问题,成为矿山环境修复者们的最棘手问题之一。对陕西紫阳废弃石煤矿进行采样分析,掌握废渣的化学成分及矿物组成,为酸性水的产生查找根源。依据《固体废物浸出毒性浸出方法水平振荡法》(HJ 557—2010),将样品破碎后分别采用蒸馏水浸泡、曝气浸泡及密封浸泡方法,来模拟自然环境下酸性水产生过程,并在模拟过程中定期采集水样进行分析测定,为后续的矿上修复治理提供依据。

基于宿州某石料厂露天废弃矿山生态修复提升实践

基于宿州市埇桥区符离镇某石料厂为例,2018年该矿山已通过治理验收,随着生态环境保护督察的开展,矿山暴露出一系列问题,针对矿山生态环境保护督察提出的问题,需进行生态环境成效提升,开展提升治理工作。本文分析了矿山存在的地质环境问题,提出了提升措施。

贵州省安龙县坡歪矿区饰面石材用灰岩矿床地质特征及开发利用前景分析

本文依托2022年“贵州省毕节—黔西南黔石资源精查项目”安龙县坡歪勘查区饰面石材用灰岩矿地质勘查成果,通过矿区地质特征和矿石特征等分析,认为矿区内矿石性能符合《饰面石材矿产地质勘查规范》(DZ/T 0291—2015)要求,饰面石材用灰岩矿石资源储量大,周边找矿潜力较大,饰面石材品种多,用途广泛且装饰效果好,具备良好品牌基础,开发利用具有广阔的市场前景。