Diesel and welding aerosols in an underground mine

Researchers from the National Institute for Occupational Safety and Health(NIOSH) conducted a study in an isolated zone of an underground mine to characterize aerosols generated by:(1) a diesel-powered personnel carrier vehicle operated over a simulated light-duty cycle and(2) the simulated repair of existing equipment using manual metal arc welding(MMAW). Both the diesel-powered vehicle and MMAW process contributed to concentrations of nano and ultrafine aerosols in the mine air. The welding process also contributed to aerosols with electrical mobility and aerodynamic mobility count median diameters of approximately 140 and 480 nm, respectively. The welding particles collected on the filters contained carbon, iron, manganese, calcium, and aluminum.     

Dust removal efficiency of high pressure atomization in underground coal mine

To master theoretical calculation for dust removal efficiency of high pressure atomization in an underground coal mine, the corresponding atomization characteristics and dust removal efficiency were both comprehensively studied in theory by virtue of related theories of hydromechanics and aerosol.According to actual measurements of flow coefficients and atomization angles of X-type swirl nozzle,computational formula was derived for atomized particle sizes of such a nozzle in conjunction with relevant empirical equation. Moreover, a mathematical model for applying high pressure atomization to dust removal in underground coal mine was also established to deduce theoretical computation formula of fractional efficiency. Then, Matlab was adopted to portray the relation curve between fractional efficiency and influence factors. In addition, a theoretical formula was also set up for removal efficiency of respirable dust and total coal dust based on dust size and frequency distribution equations. In the end,impacts of dust characteristic parameters on various dust removal efficiencies were analyzed.     

3-D discontinuum numerical modeling of subsidence incorporating ore extraction and backfilling operations in an underground iron mine in China

An underground iron mine in China has been used as a case-study to research the subsidence due to ore extraction and backfilling during open stoping operations. A 3-D discontinuum numerical model was built incorporating geologic complexities including faults and interfaces between different lithologies,and the stoping and backfilling sequence adopted from the mine plans. The stoping was carried out in two vertically stacked horizontal layers, with a total of 16 stopes. Large displacements of up to 50 cm were observed along the roof of the stopes, and a maximum surface subsidence of 22.5 cm was observed.Backfilling was found to eliminate subsequent displacements and subsidence. The extraction of the upper orebody was found to influence displacements in the lower orebody. Finally, a subsidence profile was constructed to show the subsidence at all locations along the length of the surface and region of influence on the surface.     

矿山地质环境问题及防治对策

论述了矿业开发对大气环境、水文系统、土地资源的影响及引起的地质灾害,根据矿山地质环 境质量评价,提出保护与防治矿山地质环境,实施清洁生产工艺,预防和减少污染,采用先进治理技术修 复环境污染,走绿色矿业之路。     

Determination of volumetric changes at an underground stone mine: a photogrammetry case study

Photogrammetry, as a tool for monitoring underground mine deformation, is an alternative to traditional point measurement devices, and may be capable of accurate measurements in situations where technologies such as laser scanning are unsuited, undesired, or cost-prohibitive. An underground limestone mine in Ohio is used as a test case for monitoring of structurally unstable pillars. Seven pillars were photographed over in a 63 day period, punctuated by four visits. Using photogrammetry, point clouds of the mine geometry were obtained and triangulation surfaces were generated to determine volumes of change over time. Pillar spalling in the range of 0.29–4.03 m³ of rock on individual rib faces was detected. Isolated incidents of rock expansion prior to failure, and the isolated failure of a weak shale band were also observed. Much of the pillars remained unchanged during the monitoring period, which is indicative of proper alignment in the triangulated surfaces. The photographs of some ribs were of either too poor quality or had insufficient overlap, and were not included. However, photogrammetry was successfully applied to multiple ribs in quantifying the pillar geometry change over time.     

基于未确知测度理论的地下金属矿山合理产能优选

基于未确知测度理论建立矿山合理产能优选模型,选择矿山合理产能最优方案。选取年利润等5个指标体系建立未确知测度模型,对可供选择的7个方案优选结果表明,最优方案为,矿山年产金属量15万t,年利润13.5亿元,年成本5.3亿元,全员生产率1650.6t/人,万吨通风量4.8m3/（万t·s）,服务年限11a。所得结果同灰色局势决策优化方法评价结果一致,证明未确知测度理论评判方法可靠。     

Identification of large-scale goaf instability in underground mine using particle swarm optimization and support vector machine

An approach which combines particle swarm optimization and support vector machine (PSO–SVM) is proposed to forecast large-scale goaf instability (LSGI). Firstly, influencing factors of goaf safety are analyzed, and following parameters were selected as evaluation indexes in the LSGI: uniaxial compressive strength (UCS) of rock, elastic modulus (E) of rock, rock quality designation (RQD), area ration of pillar (S_p), the ratio of width to height of the pillar (w/h), depth of ore body (H), volume of goaf (V), dip of ore body (α) and area of goaf (S_g). Then LSGI forecasting model by PSO-SVM was established according to the influencing factors. The performance of hybrid model (PSO + SVM = PSO–SVM) has been compared with the grid search method of support vector machine (GSM–SVM) model. The actual data of 40 goafs are applied to research the forecasting ability of the proposed method, and two cases of underground mine are also validated by the proposed model. The results indicated that the heuristic algorithm of PSO can speed up the SVM parameter optimization search, and the predictive ability of the PSO–SVM model with the RBF kernel function is acceptable and robust, which might hold a high potential to become a useful tool in goaf risky prediction research.     

Instability identification on large scale underground mined-out area in the metal mine based on the improved FRBFNN

To identify the instability on large scale underground mined-out area in the metal mine effectively, the parameters of radial basis function were determined through clustering method and the improved fuzzy radial basis function neural network (FRBFNN) model of instability identification model about large scale underground mined-out area in the metal mine was built. The improved FRBFNN model was trained and tested. The results show that the improved FRBFNN model has high training accuracy and generalization ability. Parameters such as pillar area ratio, filling level and the value of rock quality designation have strong influence on instability of large scale underground mined-out area. Correctness of analysis about the improved FRBFNN model was proved by the practical application results about instability discrimination of surrounding rock in large-scale underground mined-out area of a metal mine in south China.     

基于射频识别技术的煤矿井下定位系统

采用射频模块IA4421作为无线收发模块,以单片机AT89C52作为微控制器,开发出了可以定位煤矿井下人员活动区域的定位系统。介绍了系统的固定监控点和移动监控点的硬件设计,给出了系统的软件设计。该系统通过固定监控点和移动监控点之间的无线通信,获取井下人员的位置信息。     

A practical application of photogrammetry to performing rib characterization measurements in an underground coal mine using a DSLR camera

Understanding coal mine rib behavior is important for inferring pillar loading conditions as well as ensuring the safety of miners who are regularly exposed to ribs. Due to the variability in the geometry of underground openings and ground behavior, point measurements often fail to capture the true movement of mine workings. Photogrammetry is a potentially fast, cheap, and precise supplemental measurement tool in comparison to extensometers, tape measures, or laser range meters, but its application in underground coal has been limited. The practical use of photogrammetry was tested at the Safety Research Coal Mine, National Institute for Occupational Safety and Health(NIOSH). A commercially available, digital single-lens reflex(DSLR) camera was used to perform the photogrammetric surveys for the experiment. Several experiments were performed using different lighting conditions, distances to subject,camera settings, and photograph overlaps, with results summarized as follows: the lighting method was found to be insignificant if the scene was appropriately illuminated. It was found that the distance to the subject has a minimal impact on result accuracy, and that camera settings have a significant impact on the photogrammetric quality of images. An increasing photograph resolution was preferable when measuring plane orientations; otherwise a high point cloud density would likely be excessive. Focal ratio(F-stop) changes affect the depth of field and image quality in situations where multiple angles are necessary to survey cleat orientations. Photograph overlap is very important to proper three-dimensional reconstruction, and at least 60% overlap between photograph pairs is ideal to avoid unnecessary post-processing. The suggestions and guidelines proposed are designed to increase the quality of photogrammetry inputs and outputs as well as minimize processing time, and serve as a starting point for an underground coal photogrammetry study.     

Application of coal mine roof rating in Chinese coal mines

The coal mine roof rating(CMRR) is a measure of roof quality or structure competency for bedded roof types typically of underground coal mines. The CMRR has been used widely in the US, South Africa,Canada and Australia. In order to investigate the application of the CMRR system in Chinese coal mines,two coal mines in China located in Panjiang Coal Field in Guizhou Province were investigated. Field data were collected which is required to calculate the CMRR value based on underground exposure. The CMRR values of 11 locations in two coal mines were calculated. The investigations demonstrated that the chance of mine roof failure is very low if the CMRR value is more than 50, given adequate support is installed in mine. It was found that the CMRR guideline are useful to preliminarily investigate stability in Panjiang Coal Field mines.     

基于无线传感网络的煤矿井下瓦斯与温度监测系统

瓦斯和温度检测是煤矿安全生产中重要的工作,针对煤矿井下布线不方便的特点,提出了利用射频芯片的无线传感器网络来采集和传输瓦斯与温度信息的系统架构。系统由移动节点和固定节点组成。移动节点和固定节点、固定节点与固定节点之间采用无线技术传递信息。固定节点中的汇聚节点收集相应范围内的瓦斯与温度数据后通过载波方式将其传递给地面监控中心。实现了灵活组网、低开销、扩展性好和实时监测的功能,实施效果较好。     

Fire behavior of mining vehicles in underground hard rock mines

The results from a number of investigations and fire experiments are presented and analyzed in order to characterize the fire behavior of mining vehicles in underground hard rock mines. The analysis also includes fire safety and fire protection measures with respect to the mining vehicle fire behavior.Earlier studies on fires in underground hard rock mines have shown that vehicles or mobile equipment are the dominant sources of fire. A better knowledge about the fire behavior of vehicles in underground hard rock mines is therefore needed. During the analysis the direction and flow rate of the ventilation in a drift was found to have a significant impact on the fire behavior, causing for example flame tilt with rapid fire spread. The shielded sections of a vehicle will be less affected by the ventilation flow resulting in for example a decreased flame spread. It was also found that spray fires may result in considerable heat release rate but are generally of shorter duration and will not make any significant contributions to the overall heat release rate of the fully developed vehicle fire. The fire duration of a loader tire from a full-scale fire experiment was found to be at least 200 min and will largely determine the total fire duration of the vehicle. A different scenario with different conditions with for example a slower flame spread resulted in an even longer fire duration. The radiative and convective fraction will be a key factor when determining the heat transfer mechanisms involved in a fire and will vary from material to material.Calculations show that the radiative fraction of the tire fires on two mining vehicles is significantly lower than found in earlier experiments. The design and construction of the mining vehicle will have an important impact on the fire behavior and could possibly mitigate the consequences of a fire and allow fire personnel to extinguish a fire that otherwise would have had a too high heat release rate.     

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.     

Numerical study on DPM dispersion and distribution in an underground development face based on dynamic mesh

In 2012, the International Agency for Research on Cancer(IARC) classified diesel particulate matter(DPM)as a carcinogen to human. With the increased usage of diesel equipment in underground mines, miners have a high risk of over-exposure to DPM, which has drawn many concerns from the public. This study used computational fluid dynamics(CFD) to analyse the DPM dispersion and concentration distribution characteristics in an underground development face based on an onsite experiment. The DPM emitted from a moving loader under a forcing auxiliary ventilation system was simulated. The motion of the load-haul-dump(LHD) in the tunnel was represented by a dynamic mesh method. The species transport approach was applied to study the DPM behaviours. High DPM concentration zones were then identified based on the simulation results. The results could provide guidelines for work practices and be helpful to an optimum auxiliary ventilation design to reduce underground miner exposure.     

基于MapInfo的煤矿井下人员定位系统设计

介绍了以MapInfo为开发平台,以Visual Basic 6.0为开发工具的煤矿井下人员定位系统的设计与实现.首先,结合煤矿对入井人员管理的需要,进行需求分析和可行性分析:其次,从管理人员的角度分析并设计系统基本功能,进而确定了开发方案和系统设计思路;最后,根据系统设计详细介绍了在Visual Basic 6.0环境中实现软件功能的过程.该系统实现了基于电子地图的煤矿井下人员实时监控,为煤矿的安全生产提供了及时有效的井下人员定位和监控功能,以信息化手段提高了煤矿的安全生产能力.     

基于DXF的煤体结构柱状图的自动绘制

为了解决人工绘制煤体结构柱状图效率低、易出错等问题,提出了基于DXF的煤体结构柱状图的自动绘制方法.根据Auto CAD绘图功能强大、数值计算能力较弱的特点,本文编制了程序,通过程序的运行,调用绘图的原始数据,完成数据的处理,并且输出图形交换文件;图形交换文件作为数据交换的接口,可以被Auto CAD调用并实现煤体结构柱状图的自动绘制,并且该自动控制方法已经成功地应用到研究工作中.     

矿图设计、绘制与管理信息系统开发

对矿图计算机绘制与管理的发展概况、应用现状进行了分析 ,在此基础上 ,较详细地介绍了以Windows为运行环境、AutoCAD2 0 0 0为图形平台所开发的适合矿山实际情况的矿图设计、绘制与管理信息系统 ( 2MDMIS)的组成、系统的基本设置及功能特点     

基于CAN总线的中空板生产线控制系统

中论述了CAN局域网的特点及它在中空板生产中的适用性，并给出了基于CAN总线的中空板生产线控制方案。     

基于XML的数字地下空间索引QR树研究

为了提高数字地下空间数据库的存储效率与检索性能,设计基于可扩展标记语言(XML)的数字地下空间索引四叉矩形(QR) 树.该索引将检索过程涉及到的空间限制在整个索引空间的某一部分,XML利用其结构化的特点,改进了传统QR树索引文档与数据结构之间需要序列化的缺点,改善了因数据激增而下降的查找性能;同时利用XML的可扩展性,实现对索引信息规范化、结构化的描述,实现索引文档存储和数据结构组织的显式描述,解决了QR树存储开销较高、结点上溢和下溢问题,实现QR树动态维护,提高索引的稳定性.