Geopolymer-based modification of blasting sealing materials and optimization of blasting block size in coal seams of open pit mines

This research proposes the utilization of a geopolymer-based blasting sealing material to improve the profitability of coal sales and reduce the rate of coal fragmentation during blasting in open pit mines.The study first focused on optimizing the strength of the sealant material and reducing curing time.This was achieved by regulating the slag doping and sodium silicate solution modulus.The findings demonstrated that increasing slag content and improving the material resulted in an early rise in strength while increasing the modulus of the sodium silicate solution extended the curing time.The slag doping level was fixed at 80 g,and the sodium silicate solution modulus was set at 1.5.To achieve a strength of 3.12 MPa,the water/gel ratio was set at 0.5.The initial setting time was determined to be 33 min,meeting the required field test duration.Secondly,the strength requirements for field implementation were assessed by simulating the action time and force destruction process of the sealing material during blasting using ANSYS/LS-DYNA software.The results indicated that the modified material meets these requirements.Finally,the Shengli Open Pit Coal Mine served as the site for the field test.It was observed that the hole-sealing material’s hydration reaction created a laminated and flocculated gel inside it.This enhanced the density of the modified material.Additionally,the pregelatinized starch,functioning as an organic binder,filled the gaps between the gels,enhancing the cohesion and bonding coefficient of the material.Upon analyzing the post-blasting shooting effect diagram using the Split-Desktop software,it was determined that the utilization of the modified blast hole plugging material resulted in a decrease in the rate of coal fragmentation from 33.2%to 21.1%.This reduction exhibited a minimal error of 1.63%when compared to the field measurement,thereby providing further confirmation of the exceptional plugging capabilities of the modified material.This study significantly contributes to establishing a solid theoretical basis for enhancing the blasting efficiency of open pit mines and,in turn,enhancing their economic advantages.

In-pit coal mine personnel uniqueness detection technology based on personnel positioning and face recognition

Since the coal mine in-pit personnel positioning system neither can effectively achieve the function to detect the uniqueness of in-pit coal-mine personnel nor can identify and eliminate violations in attendance management such as multiple cards for one person, and swiping one's cards by others in China at present. Therefore, the research introduces a uniqueness detection system and method for in-pit coal-mine personnel integrated into the in-pit coal mine personnel positioning system, establishing a system mode based on face recognition + recognition of personnel positioning card + release by automatic detection. Aiming at the facts that the in-pit personnel are wearing helmets and faces are prone to be stained during the face recognition, the study proposes the ideas that pre-process face images using the 2D-wavelet-transformation-based Mallat algorithm and extracts three face features: miner light, eyes and mouths, using the generalized symmetry transformation-based algorithm. This research carried out test with 40 clean face images with no helmets and 40 lightly-stained face images, and then compared with results with the one using the face feature extraction method based on grey-scale transformation and edge detection. The results show that the method described in the paper can detect accurately face features in the above-mentioned two cases, and the accuracy to detect face features is 97.5% in the case of wearing helmets and lightly-stained faces.

Influence of the Haizhou Open Pit Coal Mine on the atmospheric flow over Fuxin, China

The influence of the Haizhou Open Pit Mine on the atmospheric flow in nearby Fuxin City in China was analyzed with the aid of the steady-state Navier-Stokes equations. The finite element method was used to obtain numerical solutions to these equations. The results showed that the Haizhou Open Pit Coal Mine contributes to the turbulent flow in the Fuxin City and its surroundings. However, when compared with the climatic effects, the open pit mine has a relatively small impact on the atmospheric flow over Fuxin.

Thermal recovery process of a backfilled open-pit in permafrost area at the Gulian strip coal mine in Northeast China

Timely and proper backfilling of open-pits in strip coal-mines has been an effective measurement for the recovery of the hydrothermal regimes and ecological environment in permafrost regions. In this study, numerical simulations and statistical regressions were applied for analyzing the recovery processes of the backfill and its major influencing factors for the thermal equilibrium in recently backfilled open pits at the Gulian strip coalmine in Mo'he, Northeast China. Results show that the thermal recovery time of backfilled areas is positively correlated to the backfill depth(BD) of the soils, the backfilled soil temperature(BST), and the mean annual ground surface temperature(MAGST); meanwhile, climate warming can impact on thermal regimes of the backfill area. The impact of climate warming on ground temperature of the backfill will show up significantly in about 50 years afterbackfilling(BD at 10.0 and 20.0 m, BST at 20.0°C) under the climate warming scenario(CWS) of 0.025°C·year ^(-1). Grey-relation analyses show that the sensitivity of the backfill recovery time declines in the order of the BD, BST and MAGST. On the basis of the abovementioned studies, the layer-by-layer backfilling in cold seasons is advised for more effective and more rapid recovery of thermal regimes of the backfilled open-pits in cold regions.

Optimization of Dump Bench Configuration to Improve Waste Dump Capacity of Narynsukhait Open Pit Coal Mine

In next two years, the current waste dump of Narynsukhait coal mine is predicted insufficient to accommodate the overburden as limited of the waste dump capacity. Thus, redesigning waste dump is paramount to increase capacity of the dump in future. This paper describes current condition of waste dump of Narynsukhait coal mine and then discusses the optimization of waste dump geometry by analyzing the effect of different waste dump’s bench configuration on slope performance. Optimization of the geometry is carried out by investigating and comparing the performance of geometrical combinations of bench height, bench angles and number of safety berm by means of numerical modeling. The model shows that increasing height of bench is able to induce shear stress in the bench and may initiate bench instable. However, the shear stress can be limited by having safety berm and/or reducing bench angle to satisfy the stability criteria.

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.

A study of fire propagation in coal seam with numerical simulation of heat transfer and chemical reaction rate in mining field

Spontaneous combustion of coal is a problem that affects the mining operation and generates environ-mental,economic,social and geotechnical impacts.This phenomenon has been divided into two pro-cesses:ignition and propagation.Fire propagation develops in coal seams because of a set of factors such as direction and wind speed,fracturing and temperature.In this work,heat transfer and chemical kinetics are studied from conservation equations of energy and species,respectively,using the software COMSOL Multiphysics to simulate the propagation of fires in coal seams.Two possible scenarios were analyzed that usually occur in the walls of the coal seams,such as fire focus and fire complete screens.It was found that the propagation kinetics of the fire changes depending on the temperature,the fractur-ing of rock mass and the area of fire influence.For temperature values lower than 300℃,there is con-sumption around 250 cm^3/h,values around 700℃,the consumption is 1500 cm^3/h,and for fires of 1200℃ have values of 3000 cm^3/h.Depending on the speed of propagation can vary from 4 to 17cm/day,considering on the level and fracturing of the final wall of the open pit.

基于GRID-TIN方法的露天煤矿地表模型的仿真研究

露天矿地表具有独特的表面形态特征,现有DEM难以对其地貌形态特征进行准确描述,无法满足露天矿地表地形数值模拟模型的需求。为此,以露天煤矿典型地形为研究对象,基于GRID-TIN方法和面向对象技术构建出露天矿地表数值模拟模型;用MATLAB、SOLIDWORKS等软件,对煤矿进行三维真实地形的计算机模拟与仿真,形成地形实体,具有一定的实践意义和应用价值。

Study on Dragline-Bulldozer Operation with Variations in Coal Seam Thickness

The dragline is one of the most promising surface mining machines in China. This paper studies the interac-tion between the working bench advancing speed and the stripping volume with variation in coal seam thickness. Ad-justing the bulldozing volume (depth) and/or changing the dragline bench height are proposed as means to ensure a smooth and economical mining operation. When the coal seam is getting thicker it is recommended to reduce the bull-dozing volume (depth) for a higher dragline efficiency. When the coal seam is getting thinner it is recommended to in-crease the bulldozing volume (depth) to ensure the dragline can work at the proper bench height.

Statistical analysis to establish an ignition scenario based on extrinsic and intrinsic variables of coal seams that affect spontaneous combustion

Spontaneous combustion of coal seams in open pit mines is a problem that occurs in coal mines around the world.Theories have been developed that express several factors which generate self-heating in the coal and favor combustion.The synergy of these factors contributes to the increase in the temperature of oxidation reactions,facilitating the culmination of the activation energy of the system,in which the ignition develops and the reaction is spontaneous.Currently,the incidence of each variable’s susceptibility to coal combustion is unknown,so in this work a methodology was developed to determine statistically which of the variables has the greatest contribution in the phenomenon.Descriptive statistics,atypical values detection,principal component determination,cluster analysis,and logistic regression were used to determine how many indicator variables are necessary to describe susceptibility to coal combustion.For the analysis,21,000 data from different seams of two open-pit coal mines in endwalls and abandoned pits were processed with consideration given to extrinsic and intrinsic factors.Seam temperature,atmospheric pressure,wind speed,oxygen,methane,height,ash,volatile matter,heat power,vitrinite,liptinite and the Hardgrove Index are the most influential variables in the phenomenon.

中国露天煤矿70年成就回顾及高质量发展架构体系

露天煤矿作为我国煤炭工业的重要组成部分,具有生产能力大、开采成本低、安全条件好等优势,近年来在建设规模、生产总量、开采工艺及技术装备等多方面均取得了跨越式的发展,有力保障了煤炭作为国家能源安全稳定供应的“压舱石”地位。首先回顾了新中国成立后我国露天煤矿70年来的发展历程,将其划分为起步恢复阶段(1949—1979年)、快速发展阶段(1980—1999年)、综合发展阶段(2000—2020年)和智能化初级发展阶段(2021年以后)4个时期;系统总结了每个时期的产量与数量规模、开采理论与技术、开采工艺与装备、资源开发与环境保护方面取得的突出成就。然后,探讨了现阶段露天煤矿发展面临的4个方面的主要问题,包括发展布局不均衡、可持续发展面临瓶颈、关键技术难题需深入攻关、人才短缺培养机制不完善。最后,提出构建以“安全、高效、绿色、低碳、智能”为总体目标的全链条、全周期、全要素露天煤矿高质量发展架构体系,其内涵特征包括以时效边坡理论、开采扰动指数理论、绿色开采理论、生态型开采理论、零碳负碳开采理论、智能化开采理论6种学术思想为理论基础,以灾害安全监测防控、复杂条件协同保障、生态源头减损开采、节能减污清洁利用、数字-自动-智能同建5类技术体系为核心支撑,以透明地质模型动态重构、边坡蠕滑全程精准预测、深大孔低扰动控制爆破、采空区超前探测与处置、粉尘抑制及煤自燃防治等30项关键技术为重点突破,以设计理念先进化、安全保障标准化、建设规模大型化、生产工艺综合化、开采装备智能化、核心制造国产化、矿区生态绿色化、煤炭利用清洁化、组织管理科学化、人才队伍国际化的“十化型”露天矿山为建设任务;同时给出了以规划引领为基础,以科技创新为驱动,以人才培育为保障的露天煤矿高质量发展实现路径。最终为推动我国露天煤矿向持续健康高质量方向发展提供指导。

基于平行感知卸载区边缘工程结构规范性检测

当前露天矿无人驾驶技术在卸载阶段面临的主要挑战是安全隐患,尤其是在卸载区边缘工程结构的稳定性与规范性检测方面。为应对这一挑战,提出了一种平行感知理论驱动的点云模型解析AC-VIT算法,旨在实时稳定地检测露天煤矿卸载区边缘工程结构的稳定性与规范性。首先使用无人矿卡后向激光雷达扫描得到三维点云数据,随后应用网格平均方法、统计滤波法以及映射离散网格模型对点云数据进行处理,进而通过高度场梯度特征提取进行初步地形标记,并结合改进的AC-VIT神经网络进行规范性的识别与分类,AC-VIT模型通过全基于自注意力机制的平行计算和多层级的注意力机制,能有效捕捉长距离依赖关系。此外,在人工场景仿真环境中,基于内蒙古哈尔乌素露天煤矿实际生产作业环境搭建卸载区平行仿真环境,以获得大量多样性人工场景数据,在此基础上结合实际场景数据,利用提出的算法平行执行,进行平行感知计算实验的设计和实施,完成有效的检测算法训练和科学评估。实验结果表明,平行感知理论驱动的点云模型解析AC-VIT算法在准确率方面达到了98%,较传统神经网络模型的准确率与效率有所提高。此外,AC-VIT算法的成功应用不仅增强了露天矿卸载作业的智能化水平,还为其他类似的工程结构安全检测提供了有力的技术支撑。

露天矿顺倾软岩边坡内排追踪压帮治理工程——以贺斯格乌拉南露天煤矿首采区南帮为例

软岩露天煤矿实现安全高效开采的重点是边坡稳定。为解决露天矿顺倾软岩边坡稳定性治理难题,在分析边坡稳定性主控因素的基础上,提出了露天矿顺倾软岩边坡内排追踪压帮治理工程。以贺斯格乌拉南露天煤矿首采区南帮为工程背景,兼顾采场与内排土场边坡稳定性,采用极限平衡法和数值模拟相结合的手段,设计了采场边坡的空间形态,提出了采场与内排土场边坡协同治理方案,可最大限度地安全回收边坡压覆煤炭资源。研究结果表明:弱层暴露长度是露天矿顺倾软岩边坡稳定性的主控因素,控制采场与内排土场间的追踪距离是改善边坡稳定性的有效途径;随着追踪距离的增加,边坡破坏模式从以圆弧为侧界面、弱层为底界面的切层-顺层-剪出滑动逐渐过渡为以圆弧为侧界面、弱层为底界面的切层-顺层滑动,边坡稳定性逐渐下降;内排土场及其与采场构成的复合边坡稳定性随破坏底板弱层回填岩石范围的增大呈指数函数规律提高;贺斯格乌拉南露天煤矿首采区南帮浅部边坡留设40 m运输平盘、15 m保安平盘,底帮深部边坡角29°,追踪距离控制在50 m之内时可满足安全要求;内排土场基底弱层完全破坏并回填岩石倾向长度60 m时可满足安全要求。研究成果为软岩露天煤矿边坡稳定性治理提供了新思路。

黑岱沟露天煤矿安全培训管理平台的设计构建

为了解决工学矛盾,减少传统安全培训方式对人力和物力造成的浪费,进一步提高安全培训的组织效率,提升安全培训效果;分析了我国相关法律法规对露天煤矿安全培训的要求,基于互联化+安全培训的模式构建了安全培训管理平台;安全培训管理平台实现了对培训计划、项目开展与档案管理情况的全过程管理,提升了教育培训和人才评价工作质量,更好地服务了高素质专业化人才队伍建设。

露天煤矿排土场边坡植被恢复群落稳定性研究

为了揭示露天煤矿排土场边坡植被恢复群落稳定性的动态特征和变化模式,以内蒙古北电胜利露天煤矿4个排土场为研究对象,选取Shannon-Wiener多样性指数、Margalef丰富度指数、Pielou均匀度指数和Simpson优势度指数、植被盖度、植被高度、地上和地下生物量8个指标,构建了基于群落结构稳定性与群落功能稳定性的排土场边坡植被恢复群落稳定性评价体系,采用综合评价法对处于人工植被恢复中的内排土场和恢复年限分别为4 a、5 a、8 a的沿帮排土场、南排土场和北排土场的南、北方向边坡植被恢复群落稳定性进行综合评估,并对群落稳定性因子与土壤含水量、有机质、全氮、全磷、全钾等环境因子间关系进行分析,探究影响排土场边坡群落稳定性的影响因素。结果表明:(1)随着恢复年限的增加,边坡植被群落稳定性整体呈稳步上升趋势,但与草原站背景值相比,其综合评价指数处于较不稳定或不稳定状态。(2)随着恢复年限的增加,排土场边坡群落稳定性由结构稳定性主导转向功能稳定性主导。恢复初期受人工影响,物种多样性提高,结构稳定性较高,随着时间的推移,结构稳定性波动下降,功能稳定性上升,其中地下生物量增长迅速,生物量向地下转移,进而形成矿区特有的植物群落结构稳定与功能稳定转变特征。(3)从坡向来看,随着恢复年限的增加,边坡群落稳定性逐渐由南坡优于北坡转变为北坡优于南坡。(4)南坡的结构稳定性与环境因子的相关性较高,而北坡的功能稳定性与环境因子相关性较高,表明不同坡向的群落采用了不同的响应策略以适应环境的变化,丰富的有机质和全氮含量对排土场边坡群落功能性稳定性会产生积极影响。

基于土壤肥力恢复力模型的河曲露天煤矿复垦治理效果评价

以河曲旧县露天煤矿排土场为研究对象,采用模糊层次分析法(FAHP)和专家评分理论法建立了露天煤矿排土场土壤肥力综合评价模型,获得土壤结构稳定性、土壤保水能力、土壤保肥能力及土壤生物活性4项准则和25个因素,利用YAAHP计算软件确定了排土场土壤肥力恢复力各影响因素的权重。结果表明,评价体系准则层中土壤保肥能力权重最大(0.5477),其次分别是土壤保水能力(0.1980)、土壤生物活性(0.1408)和土壤结构稳定性(0.1135),因素层有机质F1权重最高(0.1162);根据现场抽样,已复垦区的土壤质量水平要高于未复垦区的土壤质量水平,整体来看土壤质量水平均处于中等偏下和较差水平,土壤恢复力的主要因素是土壤保肥能力,特别是土壤有机质含量。土壤肥力恢复力模型为提高排土场土壤质量、加快土壤重构、促进土壤生态系统恢复提供治理思路。

露天矿山无人驾驶编组运行关键技术

分析了当前国内外露天矿山智能化发展现状;介绍了无人驾驶编组运行阶段关键技术,包括:构建智能化管理与监控系统、无人驾驶改造、数据实时传输,以及构建协同作业管理系统和无人运输安全防护网,从而实现露天矿山装、运、排联合作业智能化。结果表明:逐步完善监控、数据处理、路径规划、防护措施,可保障无人驾驶编组运行稳定推进,为消除人员不安全行为、保障职工生命健康、降本增效提供现实可行性,从而实现智能化露天矿山安全稳定发展目标。

GB-InSAR集成GIS的露天煤矿边坡变形监测

对露天矿边坡进行实时、精确测量可为边坡提供可靠的预警和治理信息,直接关系到露天矿的生产连续性和效益。地基SAR干涉测量技术(GB-InSAR)是最近10年发展起来的一种相对较新的变形监测技术,具有全天候、全天时的观测特点。而国内针对露天矿边坡变形监测大多处于试验阶段,缺乏长时间连续观测的能力,本文详细地阐述了GB-InSAR的基本原理,并将GBInSAR得到的变形数据与GIS有机地连接起来,利用GIS强大的空间显示、分析能力,高效、实时、直观地展示变形信息,为露天矿生产提供了有力的决策支持。

锡林郭勒盟大型露天煤矿区地质环境时空演化评价

内蒙古锡林郭勒盟大型露天煤矿区经过20多年的开发,产生了一系列矿山地质环境问题,矿区地质环境在一定程度上遭到破坏,因此,开展大型露天煤矿区地质环境时空演化评价可为矿区生态地质环境修复提供参考。本文对锡林郭勒盟3个大型矿区进行地质环境时空演化评价。首先通过现场调查,明确了研究区主要的矿山地质环境问题,包括植被覆盖度下降、土地压占(排土场和工业场地)、地形地貌景观破坏(露天采坑)和含水层破坏等4类;其次利用遥感影像定量获取了2000—2020年之间的矿山地质环境问题信息,并建立了矿山地质环境评价指标体系;然后应用层次分析法确定了矿山地质环境评价指标的权重,并通过基于GIS的影响指数模型对矿山地质环境影响进行了评价和区划,探讨了矿山地质环境时空演化规律。研究结果表明:(1)3个大型矿区植被覆盖度下降区域的面积、排土场压占土地面积和露天采坑破坏地形地貌景观面积随时间不断增加;(2)大型矿区采矿对地质环境的影响划分为无影响区、轻微影响区、一般影响区、较强影响区和强烈影响区5个等级分区;(3)3个大型矿区地质环境时空演化规律基本相同,不同影响区的空间分布特征和面积随时间变化的规律不同。

露天煤矿环境下基于LiDAR/IMU的紧耦合SLAM算法研究

随着人工智能和无人驾驶等相关学科的快速发展,煤矿装备的智能化和无人化成为了新的趋势。智能设备的应用将大幅提高煤矿作业的生产力以及人员安全性。露天煤矿地形复杂,与城市环境相比无明显的几何特征,具有分段相似性,利用现有以激光雷达为主的同时定位与建图(Simultaneous Localization and Mapping,SLAM)方案在该环境下易出现定位漂移和建图误差较大等现象。针对上述问题,提出了一种基于激光雷达(Light Detection and Ranging,LiDAR)和惯导(Inertial Measurement Unit,IMU)紧耦合的SLAM算法,该算法使用LiDAR和IMU两种传感器作为数据输入,对数据进行预处理,前端利用迭代扩展卡尔曼滤波器将预处理后的LiDAR特征点与IMU数据相融合,并使用后向传播来矫正雷达运动畸变,后端利用雷达相对位姿因子将LiDAR帧间配准结果作为约束因子与回环因子共同完成全局因子图优化。利用开源数据集和露天煤矿实地数据集验证了算法的鲁棒性和精确性。试验结果表明在城市结构化环境中文中所提算法与当前激光SLAM算法精度保持一致,而针对长达两千多米的露天煤矿实地环境,所提算法较FAST-LIO2、LIO-SAM紧耦合算法在定位精度上分别提高了46.00%和23.15%,且具有更高的鲁棒性。