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.

High efficiency of heavy metal removal in mine water by limestone

The removal of Cd, Cu, Ni and Zn from dilute mine water by using several geological materials including pure limestone, sand, carbonaceous limestone and brecciated limestone was performed on a laboratory scale. The results showed that to add geological materials in combination with sodium carbonate injection would notably enhance the efficiency of heavy metal removal to varying degrees. Pure limestone was found the best one among the four materials mentioned above for removing heavy metals from mine water. The removal efficiencies of pure limestone when it is ground as fine as 30–60 meshes are 58.6% for Cd, 100% for Cu, 47.8% for Ni, and 36.8% for Zn at 20℃. The optimum pH is about 8.9 to 9.1. The mechanism of higher effective removal, perhaps, is primarily due to co-precipitation under the control of calcite-related pH value. According to this research, Na2CO3 injection manners, including slug dosing and drip-wise, seemed to have little impact on the efficiency of heavy metal removal.

Hydro-geochemistry evolution in Ordovician limestone water induced by mountainous coal mining: A case study from North China

This research aimed to investigate the changing mechanism of hydro-geochemistry in Ordovician limestone karst(OL) water induced by mountainous coal mining activities. Thus, the hydrogeochemistry evolution of OL water over 40 years within a typical northern mountainous coal mine named Fengfeng Mine was studied by using Piper diagram, Gibbs scheme, ions correlation and Principal component analysis(PCA) methods. Results showed that, except for HCO3^-, the ions of Ca^2+, Mg^2+, SO4^2-,Na^++K^+, Cl^- and total dissolution solids(TDS) values all increased by years as mining continues. Different hydro-geochemical characteristics in different periods can reflect different water-rock interactions.Accordingly, sulfates dissolution gradually took place of carbonates in water-rock interaction. Especially,OL water-rock interactions in different periods were all affected by rock weathering and evaporationconcentration together. At last, evaporationconcentration co-effect dominated the hydrogeochemistry evolution slowly, along with significant cations exchange over years.

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.

The Effect of Tree Species on the Chemical Properties of Soil in the Rehabilitation of a Limestone Quarry at Athi River, Kenya

A comparison of field performance of Acacia xanthophloea, Schinus molle, Casuarina equisetifolia and Gravellia robusta plant species was made in an exhausted limestone quarry, backfilled with limestone mine waste in a semi-arid area in Athi River, Kenya. The aim of the study was to determine if the tree species had an influence on the soil chemical properties. The soil had alkaline pH ranging from 8.0 to 8.98, low nitrogen content （〈 0.03%）, moderate phosphorus concentrations ranging from 44.15 ppm to 21.33 ppm and high to moderate exchangeable cations （Na, Ca, Mg and K）. All the tree species exerted a positive influence on soil properties necessary for plant growth. The pH values and total phosphorus were relatively lower in soils close to the trees （0.5 m） and increased with distance from the trees, while the soil values for total nitrogen and exchangeable cations were relatively higher close to the trees. C. equisetifolia had the best growth performance and a higher positive influence on the soil chemical properties necessary for plant growth followed by A. xanthophloea. It was concluded that trees should remain a feature of quarry rehabilitation because of their role in maintaining the biophysical environment.

Geochemical assessment of a siliceous limestone sample for cement making

A low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, has been investigated for its suitability for cement making. Petrological as well as X-ray diffraction pattern studies indicated that the limestone sample was crystalline and dominantly composed of calcite and quartz. They are simple in mineralogy, and yet they have variable silica and lime contents. Geochemical analysis results of twenty five hand picked samples indicated that the limestone from the Jayantipuram mine shows a wide range of variations in LOI (29.94% to 40.64%), SiO2 (6.14% to 27.18%), CaO (37.93% to 50.78%), Al2O3 (0.49% to 2.27%) and Fe2O3 (0.28% to 2.4%). MgO, K2O, Na2O, TiO2 and MnO2 are present in traces. CaO with LOI shows a strong positive correlation where as CaO with SiO2 shows a strong negative correlation because of mineralogical factors. The chemical composition of the limestone reflects its mineralogical composition. The distribution of various elements in the acid-soluble fraction has been studied by the factor analysis method in order to interpret in terms of their mineralogy, sedimentary environment and diagenesis. Mineralogy, recrystallization and other diagenetic changes are the main factors affecting the distribution of the elements and their mutual relationships in the limestone. The aim of this paper is also to analyze how significantly the two parameters, silica modulus and lime saturation factor, influence this low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, for the cement making process from the geochemical data.

阳泉市石灰岩矿整合成效分析

阳泉市石灰岩分布广泛,开采时间长,矿山分布多、规模小。结合阳泉市石灰岩矿产资源分布,本文分析非煤矿山整合前后的石灰岩矿采矿权设置,提出整合后矿山建设建议。随着非煤矿山的整合,石灰岩矿数量压减近50%,生产规模大幅提升,基本实现开采规范化、管理流程化与产业集群化。阳泉市石灰岩矿业发展实现量变到质变的提升。

陕西省煤矿典型水灾隐患特征及治理技术

陕西省煤炭资源丰富,2022年煤炭产量达7.46亿t,是我国主要产煤省份之一。由于全省煤矿区地质及水文地质条件差异明显,煤矿水灾类型多样,随着近年煤炭开采强度的增大,水灾事故时有发生,防治水形势较为严峻。以煤炭赋存条件为基础,系统总结区域水文地质结构特征,界定典型水灾类型及各类水灾影响区域分布,论述典型水灾的形成机理及特征,并提出了相应的防控技术。研究表明:(1)陕西省主要煤炭产区分为陕北、黄陇、渭北三大区,陕北侏罗纪煤田主要有顶板松散沙层水灾隐患、厚层砂岩水灾隐患、溃水溃沙灾害,局部区域分布有烧变岩对煤矿造成水灾隐患;黄陇煤田主要受顶板巨厚砂岩水灾隐患、离层溃水隐患、泥砂溃涌灾害隐患威胁;陕北石炭—二叠纪煤田和渭北煤田,主要受到煤层底板奥陶系灰岩水灾隐患威胁。(2)陕北侏罗系煤田顶板水灾隐患主要为顶板含水层受开采导水裂隙带扰动形成,导水裂隙波及砂岩含水层或松散沙层可形成持续大流量涌水,部分区域充水强度较大,在短时间水量较大超过排水系统能力时造成顶板水灾,在薄基岩区域垮落带直接导通松散沙层时可转变为溃水溃沙灾害,导水裂隙带影响到烧变岩富水区域时可形成瞬时水量大且持续的烧变岩水灾;黄陇煤田顶板巨厚砂岩含水层受采动导水裂隙带波及形成高强度持续涌水并可能形成顶板水灾,当含水层下部隔水层厚度较大时,可能形成离层溃水灾害,当近煤层顶板岩层松软遇水易崩解时可转变为泥砂溃涌灾害;陕北石炭—二叠纪煤田和渭北煤田,煤层开采底板扰动破坏带或断层等构造导通奥陶系灰岩含水层时,会引发极为严重的底板突水灾害,该类灾害具突发性强、瞬时水量大的特征。(3)各区域的顶板水灾隐患治理技术主要包括钻孔疏泄、注浆治理、开采参数控制等,底板水灾隐患治理技术主要包括区域注浆加固及封堵等;烧变岩水灾隐患主要采取帷幕注浆与钻孔探放有机结合的防治技术。

某石灰岩矿露天台阶爆破设计及安全分析

为了提高石灰岩矿开采效率,确保爆破安全,以四川省某石灰岩矿为研究背景,基于理论分析和现场经验,确定了台阶爆破方案,并对台阶爆破孔网参数进行了设计。同时,以爆破振动、爆破飞石、爆破冲击波和爆破噪音的安全允许距离为指标,对爆破效果进行了分析评价。研究结果表明:对于120mm的炮孔,爆破振动安全允许距离为30.0m;爆破冲击波安全允许距离约为193m,爆破噪音安全允许距离约为196.9m。相比于齐发起爆,毫秒延时起爆可以有效减少爆破飞石的产生,为防止某些炮孔由于与其临近炮孔之间的延时时间差过大而导致飞石加剧,并考虑到岩石的挤压破碎效果,计算确定40ms作为各炮孔间的延期时间。此外,预裂爆破可大幅降低爆破振动对露天矿边坡的危害。设计了预裂爆破方案及参数,预裂孔起爆时间早于主爆孔150ms起爆。爆破台阶自由面法向应背离公路和民房方向,或者与公路和村庄走向平行,能够有效保护附近构筑物;非爆破开采应该滞后于爆破开采,为爆破开采提供安全遮挡。研究成果为台阶爆破设计与施工提供一定指导。

新集矿区深部1煤层底板奥灰岩溶突水危险性评价

奥灰岩溶裂隙含水层是影响华北型煤矿深部开采的重要水害,在水-岩相互作用下奥灰含水层易导致煤层底板突水。为进一步认识奥灰岩溶突水问题,文章以新集矿区深部1煤层开采为例,利用矿区近些年最新积累的奥灰钻孔资料,选取断层强度指数、断层交叉点与尖灭点、含水层水压、富水性、隔水层等效厚度、脆塑比7个因素作为奥灰岩溶突水的主控因素,并结合层次分析法(analytic hierarchy process,AHP)确定各主控因素影响权重。运用地理信息系统(geographic information system,GIS)空间分析功能建立各主控因素专题图,通过对专题栅格图归一化处理,将各主控因素按照权重进行空间复合叠加,最终获得1煤层底板奥灰岩溶突水危险性评价分区结果。将评价结果与突水系数法计算结果对比分析可知,基于GIS的煤层底板突水危险性评价方法更符合矿区实际地质情况,可以为矿区深部煤层开采与水害防治工作提供参考依据。

粒径分布对石灰岩矿爆破粉尘表面润湿特性的影响

为探究露天石灰岩矿爆破粉尘的表面润湿特性,以安徽省铜陵石灰石矿山爆破粉尘为研究对象,利用激光粒度分析仪、X射线衍射仪以及扫描电子显微镜分别测量粉尘的粒径分布、矿物成分和表面形貌,分析其对石灰岩爆破粉尘润湿特性的影响。通过对比实验数据分析,得出:亲水性粉尘(HD)平均粒径D(4,3)要比疏水性粉尘(HCD)大2.416μm,更易被湿润;两者可被人体吸入粉尘(粒径≤10μm)占比分别为24.34%,28.08%,HCD更有可能导致人们患呼吸性疾病;HD的表面形貌比HCD更光滑平整,相应的具有更好的湿润性能。

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.

渭北煤田主要充水含水层氢氧同位素特征及指示意义

为探查矿区含水层补径排特征,开展了含水层氢氧同位素化学研究。以渭北煤田为研究对象,对研究区4个矿区的3个主要充水含水层和采空区,采集并测试了31组稳定氢氧同位素样品和7组放射性氢氧同位素样品。结合矿区水文地质资料与矿井涌水特征,综合分析了研究区充水含水层同位素地球化学特征及其指示意义。研究结果表明:研究区奥陶系灰岩含水层浅埋和深埋范围普遍与大气降水有联系。董家河煤矿相近太原组灰岩含水层和奥陶系灰岩含水层水力联系密切。研究区奥陶系径流方向整体为自西向东流动。研究区太原组灰岩含水层存在氧漂移现象,说明该含水层在煤炭开采扰动下,水岩相互作用密切。

韧性视角下华北型煤田底板承压灰岩水原位保护技术研究

目的为推进保水开采技术高质量发展,有效解决华北型煤田底板承压灰岩水原位保护问题,方法根据扰动下系统韧性演化特征,从韧性抵抗力、恢复力和适应力出发,分析煤层底板在采动和承压水影响下由抵抗到恢复及再适应的全过程。基于“精准、高效、全面”的核心内涵,构建以“治理靶区精准确定、多分支井高效注浆、保水效果全面评价”为主体的华北型煤田底板承压灰岩水原位保护技术框架。结果结果表明:治理靶区精准确定包括垂向层位确定和横向靶位确定;多分支井高效注浆包括定、钻、注3个步骤;保水效果全面评价包括底板岩层注浆效果评价和水资源承载力恢复评价。根据底板破坏深度和临界隔水层厚度计算,确定底板注浆垂向层位,根据关键指标参数探测和脆弱性指数模型计算确定底板注浆横向靶位,形成底板注浆靶区的量化确定方法并开发相应的软件系统。多分支井注浆结合随钻定向技术,对相关裂隙等进行注浆封堵,减少直井段数量,提高钻井效率。针对保水开采中“安全开采”和“水资源保护”理念,提出基于底板岩层注浆效果探测和水资源承载力恢复监测的原位保水效果评价方法。结论在安徽某矿进行工程应用,保障底板承压灰岩水上开采煤层安全性的同时,兼顾矿区经济效益与生态环境发展。研究结果完善了承压水上保水开采技术体系,为后续研究及现场应用提供借鉴。

东至县花山地区金矿体特征及金的成因探讨

花山金矿地区大地构造位置处于江南过渡带南部,江南深大断裂南侧,东至断裂西侧。矿体受近东西向断层控制,含矿岩石为早寒武世杨柳岗组条纹状泥灰岩、粘土页岩。主要矿石矿物为黄铁矿、毒砂、辉锑矿等。其中花岗闪长斑岩黄铁矿化发育,绢英岩化发育,并伴随较普遍的细脉浸染状金矿化,具有斑岩型金矿特征,在江南过渡带应把中酸性斑岩体作为寻找斑岩型金矿的重点。找矿标志有构造、岩性、蚀变等。

基于DIMINE-MIDAS/GTS的采空区稳定性分析

随着矿山的开采,形成大量的采空区,采空区的存在严重威胁井下作业人员安全,并影响企业的长期发展。为了保障安全生产,采用室内试验、数值模拟等技术手段针对南川河石灰岩矿井的地下采空区进行了稳定性分析。在室内岩石力学试验基础上,根据Hoek-Brown准则及其强度参数的估计法,对该矿的岩石力学参数进行折算,利用大型三维矿山软件DIMINE建立有限元三维数值模型,结合有限元数值分析软件MIDAS/GTS进行矿山开采及采空区稳定性有限元数值模拟分析。得出结论:老采空区顶板出现拉应力破坏,局部最大拉应力为2.27 MPa,易发生冒顶片帮事故;13号矿柱产生主应力集中,处于压应力破坏;采空区周边矿柱仅有少量单元发生塑性破坏,塑性区主要存在于采空区顶板;地表位移沉降较小,矿山采空区基本处于稳定状态。

河南某水泥用灰岩矿山废石综合利用试验研究

河南某水泥用灰岩矿废石为剥离的顶板高MgO白云岩,总量达6000余万吨。为评价其综合利用方向,本文通过实验室流程试验,对废石开展综合利用研究。通过试验得出:废石放射性指标内照指数(I_(Ra))0.12、外照指数(I_(γ))0.13,饱和抗压强度平均值61.81MPa,碱活性反应膨胀率平均0.090%,坚固性平均值7.49%,压碎指标平均值13.87%,各指标均满足Ⅱ类建筑用石料质量指标要求,可作为建筑用石料综合利用。该研究为同类水泥用灰岩矿山废石综合利用提供了方向。

基于FLAC3D的石灰岩矿区岩溶塌陷数值模拟研究

矿区为露天凹陷式开采的石灰岩建材矿山,随着矿山开采以及地下水抽排,导致矿坑周边岩溶塌陷大量产生,严重影响矿山安全生产和周边群众生产生活。利用FLAC3D技术、天然电场选频法勘探和地质综合分析掌握岩溶塌陷发生机理和分布规律,研究结果表明矿坑东侧、北侧和南侧断裂构造发育;矿山生产抽排地下水以及采矿爆破引起真空吸蚀、流水潜蚀导致矿坑周边岩溶塌陷;基于FLAC3D技术矿区岩溶塌陷数值模拟分析,数值模拟结果与地质分析、物探结论和塌陷现状基本一致。研究结果为后期岩溶塌陷的防治提供了科学依据。