A mathematical model of the temperature in a coalfield fire area

The regular pattern of temperature change in a coalfield fire area while the fire is being extinguished was studied. To determine the extinguishing effect, a series of linear, logarithmic, polynomial or exponential mathematical regression models were constructed using the observed temperature data from the Xinjiang coalfield fire extinguishing project. The quadratic polynomial mathematical model had the best fit. A large coal fire oven was also used to simulate the coal fire extinguishing process. The same mathematical regression experiments were carried out on that observed data. The results verified that the quadratic polynomial ma-thematical model had the best fit. Therefore, a quadratic polynomial mathematical model is proposed to accurately model the tem-perature-time relationship in a coalfield fire area. An application to coalfield fire suppression shows that the deduced mathematical model can be used to predict the temperature conditions and to determine the effect of fire extinguishing, thereby helping to speed up the fire suppression process in the coalfield fire area.     

计算机辅助设计在露天爆破中的应用开发

简要介绍了一个露天爆破计算机辅助设计的主要功能及其开发过程。     

Stability assessment and feature analysis of slope in Nanfen Open Pit Iron Mine

Under the combined influences of special topography and the long term mining in Nanfen Open Pit Iron Mine, many large scale landslide masses appeared in heading side of stope, and tens of millions of iron mine is buried underside, making great economic losses. In order to guide the safety mining and increase the supply quantity, this paper through the use of MSARMA-method and the “MSARMA evaluation and analytical system for slope stability analysis” based on this method, which aimed at the quantitative evaluating of the slope stability before and after the actual mining below the slip mass, and the sensitivity analysis for the main influencing factor, providing scientific proof for the parameter optimization of open mine surface slope, the security and sustainable exploitation.     

Numerical simulation to determine the gas explosion risk in longwall goaf areas: A case study of Xutuan Colliery

Underground gassy longwall mining goafs may suffer potential gas explosions during the mining process because of the irregularity of gas emissions in the goaf and poor ventilation of the working face, which are risks difficult to control. In this work, the 3235 working face of the Xutuan Colliery in Suzhou City, China, was researched as a case study. The effects of air quantity and gas emission on the three-dimensional distribution of oxygen and methane concentration in the longwall goaf were studied. Based on the revised Coward’s triangle and linear coupling region formula, the coupled methane-oxygen explosive hazard zones (CEHZs) were drawn. Furthermore, a simple practical index was proposed to quantitatively determine the gas explosion risk in the longwall goaf. The results showed that the CEHZs mainly focus on the intake side where the risk of gas explosion is greatest. The CEHZ is reduced with increasing air quantity. Moreover, the higher the gas emission, the larger the CEHZ, which moves towards the intake side at low goaf heights and shifts to the deeper parts of the goaf at high heights. In addition, the risk of gas explosion is reduced as air quantities increase, but when gas emissions increase to a higher level (greater than 50 m³/min), the volume of the CEHZ does not decrease with the increase of air quantity, and the risk of gas explosion no longer shows a linear downward trend. This study is of significance as it seeks to reduce gas explosion accidents and improve mine production safety.     

青海木里煤田天然气水合物稳定带研究

天然气水合物稳定带是天然气水合物成藏的必要条件,气体组分、地温梯度、多年冻土层厚度是影响稳定带的主要因素.本文以青海木里煤田钻探得到的天然气水合物实物样品的气体组分为依据,利用Sloan的天然气水合物相平衡程序(CSMHYD),计算得到该区天然气水合物温压相平衡曲线;通过对煤田钻孔简易测温数据的处理,获得冻土层厚度和冻土层下地温梯度等重要数据.基于上述基础数据,提出利用计算机编程模拟计算单孔天然气水合物稳定带参数的方法,根据单孔数据首次编制获得木里煤田天然气水合物稳定带底界埋深等值线图.研究结果表明:木里煤田85个钻孔的天然气水合物稳定带厚度均值达1 000m,显示本区具有天然气水合物赋存的广阔空间;稳定带底界埋深等值线展示了水合物温压平衡区间的平面分布特征,底界埋深超过1 500m的聚乎更矿区南部、哆嗦公马矿区中部和雪霍立矿区东部,是天然气水合物赋存的有利区域.     

矿井水铬污染的实验研究——以徐州-大屯矿区为例

煤矿矿井水中的重金属元素Cr对人体和环境具有危害。以徐州-大屯矿区为研究对象,采用淋滤模拟实验等方法,对煤层及其顶底板岩石中Cr的溶出行为及矿井水Cr污染潜势进行了研究.结果表明,煤层顶板渗透水中Cr的质量分数远高于煤浸泡水中其质量分数,表明顶底板岩石具有更高的Cr污染潜势;矿井水中Cr主要来源于煤层顶底板中伊利石向高岭石的转化;环境pH值对矿井水中Cr的含量起到控制作用,pH值、Eh值及温度对Cr的溶出行为产生影响.Cr的溶出量在中性条件下较小,在酸性或碱性条件下比中性条件下高出一个数量级以上。较高的环境Eh值和环境温度将加速Cr的溶出.     

基于项目体系的CDIO教学改革的探索与实践——以高职数控技术专业为例

在高职《数控机床加工工艺与实施》课程改革中应用CDIO理念,改变传统教学中学生被动的学习,通过CDIO理念的引入,使学生成为学习的主体,教师起到引领、主导作用,从而增强学生学习的积极性,在实际教学中将课程内容项目化,通过对实际的项目教学,增强学生的实践能力,为就业打下良好的基础。     

鹤壁矿区瓦斯综合治理技术研究

分析并研究了鹤壁矿区瓦斯涌出规律,阐述了鹤壁矿区瓦斯综合治理基本方法,提出了以瓦斯抽放和通风方式改革为主的瓦斯综合治理技术.对回采工作面提出采用综合抽放、进行采区通风方式改革、选择合理的采煤工艺等技术;对于掘进工作面提出了边掘边抽、大力推广应用对旋式风机等综合治理技术,指明了鹤壁矿区未来瓦斯治理技术的发展方向。     

鹤壁矿区瓦斯综合治理技术研究

分析并研究了鹤壁矿区瓦斯涌出规律 ,阐述了鹤壁矿区瓦斯综合治理基本方法 ,提出了以瓦斯抽放和通风方式改革为主的瓦斯综合治理技术 .对回采工作面提出采用综合抽放、进行采区通风方式改革、选择合理的采煤工艺等技术 ;对于掘进工作面提出了边掘边抽、大力推广应用对旋式风机等综合治理技术 ,指明了鹤壁矿区未来瓦斯治理技术的发展方向     

Water protection in the western semiarid coal mining regions of China: A case study

The coal industry in China has been moving from the semiarid eastern to the drier western regions since the beginning of this century. Water protection is of the utmost concern for coal mining in these regions. Lu’an, as one of the state coal mining bases in China, has been seeing increasingly heavier pressure for the protection of water resources. This article considers Lu’an as an example and describes the ways these concerns may be alleviated. High mine-water utilization rates have effectively reduced wasting of water and, consequently, have reduced water demand. Using the top layers of the Ordavician as aquifuge barriers can prevent floor karst water inrush into the longwall face and can protect the regional Ordovician karst water resources at the same time. The strength of the overlying Quaternary clay can protect against roof collapse and has successfully preserved the Quaternary porous water resource.     

Towards an optimization design of seepage control:A case study in dam engineering

High dams generally suffer from higher seepage risks in their foundations, and seepage control is an important technology for limiting the amount of leakage and improving the stability of the foundations. In this study, a procedure was proposed for optimization design of seepage control system in large-scale hydropower projects, which relies on sufficient characterization of site conditions and proper quantification of the performance of the seepage control system. The proposed procedure was applied to the design of seepage control system in the Mengdigou Hydropower Station consisting of a double-curvature arch dam201 m in height. An optimized layout of the seepage control system, including the extended length of grout curtain, the rows of grouting holes and the spacing of drainage holes, was suggested. The proposed procedure provides a guide with lower risk and higher confidence for performance assessment and optimization design of seepage control systems in high dam engineering.     

水源地安全与水源地建设问题分析——以乌鲁木齐市为例

饮用水安全问题是目前社会最为关心的问题之一,而水源地的安全是饮水安全的重中之重.城市水源地作为城市水资源供给的源泉所在,对城市可持续发展、社会的和谐稳定及全面小康社会的建设具有十分重要的意义.对乌鲁木齐乌拉泊水库、红雁池水库,柴窝堡等水源地的建设状况和水源地安全内涵作了探讨,并根据水源地建设和安全现状,提出保障饮用水水源地安全的基本对策与建议,对保障乌鲁木齐市水源地的安全及城市居民饮用水安全具有重大意义.     

快速城市化地区土地利用变化研究——以浦东新区为例

以航空遥感影像为数据源,以GIS为分析手段,通过土地利用变化量、土地利用年变化率、土地利用相对变化率和转移矩阵详细分析了浦东花木镇土地类型的变化幅度、速度与方向,揭示了快速城市化地区土地利用的变化特点与规律。结果表明:(1)研究区呈现显著的快速城市化特征,土地利用/覆被格局发生了很大变化;(2)与浦东新区全区相比,城乡结合部土地利用受到人类活动强烈扰动且道路指向性明显;(3)研究区土地利用数量变化存在明显的空间分异,耕地转出量最大,工业用地增加迅速;(4)交通基础设施的不断完善是城市用地扩展的主导驱动因子。     

基于不同测井曲线的煤体结构识别 ——以大同煤田塔山矿为例

为探究大同煤田塔山矿3～5号煤层煤体结构特征及对应的测井曲线识别方法,以塔山矿50余口钻孔数据和测井结果为研究依据,通过测井曲线解释、构造煤煤体结构指数和原生煤比例计算等数学方法结合,进行构造煤发育特征的定性和定量分析,并绘制塔山矿构造煤平面展布规律图.结果表明:塔山矿3～5号煤层在测井曲线上表现为高电阻率、高声波时差...     

Explosive limits of mixed gases containing CH4, CO and C2H4 in the goaf area

The explosive gases CO and C2H4, released mainly flammable gases during the process of coal self-ignition, are of the most important ingredients of the multi-component gases in goaf areas, along with CH4. We have determined some of the parameters of explosive properties of the one-component gases CH4, CO and C2H4 using an explosive trial device of polybasic explosive gas mixtures and emphasized particularly the effect on the limits of explosive concentration of the binary explosive mixed gases CH4+CO, CH4+C2H4, as a function of the amount of CO, C2H4 and inert flame resisting gases (N2, CO2). The experimental results show that the effect of inert gases on the explosive limits of mixed gases, given the property of explosive gas, is obvious: the inert gases (N2, CO2) possess some inhibitory effects on the explosion of the multi-component explosive gas mixtures. The results will provide some experimental support to suppress the occurrence of the gas explosions in goaf areas and provide some directions for designing explosion-proof electric equipment and fire arresters.     

Assessing ability of a wet swale to manage road runoff:A case study in Hefei,China

The ability of a wet swale,constructed in an area of poor soil permeability,to manage runoff from a roadway was monitored through 27 storm events over a period of 8 months.During the monitoring period,the wet swale reduced the total runoff volume by 50.4%through exfiltration and evapotranspiration.The wet swale significantly decreased the influent pollutant concentrations,and the effluent mean concentrations of total suspended solids,total phosphorus,chemical oxygen demand,ammonium,oxidized nitrogen,and total nitrogen in the effluent were 31 mg/L,0.10 mg/L,29 mg/L,0.52 mg/L,0.35 mg/L and1.28 mg/L,respectively.Pollutant loads were also substantially reduced from 70%to 85%.Plant uptake played an important role in nutrient removal in the wet swale.Approximately half of the nitrogen(53.8%)and phosphorus(51.5%)that entered the wet swale was incorporated in above-ground plants.It is shown that wet swales are useful for managing runoff from roads in areas of poor soil permeability.     

Large-scale destress blasting for seismicity control in hard rock mines: A case study

Destress blasting is a rockburst control technique where highly stressed rock is blasted to reduce the local stress and stiffness of the rock, thereby reducing its burst proneness. The technique is commonly practiced in deep hard rock mines in burst prone developments, as well as in sill or crown pillars which become burst-prone as the orebody is extracted. Large-scale destressing is a variant of destress blasting where panels are created parallel to the orebody strike with a longhole, fanning blast pattern from cross cut drifts situated in the host rock. The aim of panel destressing is to reduce the stress concentration in the ore blocks or pillars to be mined. This paper focuses on the large-scale destress blasting program conducted at Vale's Copper Cliff Mine(CCM) in Ontario, Canada. The merits of panel destressing are examined through field measurements of mining induced stress changes in the pillar. The destressing mechanism is simulated with a rock fragmentation factor(a) and stress reduction/dissipation factor(b). A 3D model is built and validated with measured induced stress changes. It is shown that the best correlation between the numerical model and field measurements is obtained when the combination of a and b indicates that the blast causes high fragmentation(a = 0.05) and high stress release(b = 0.95) in the destress panel. It is demonstrated that the burst proneness of the ore blocks in the panel stress shadow is reduced in terms of the brittle shear ratio(BSR) and the burst potential index(BPI).     

Deformation control of asymmetric floor heave in a deep rock roadway: A case study

In order to control asymmetric floor heave in deep rock roadways and deformation around the surrounding rock mass after excavation, in this paper we discuss the failure mechanism and coupling control countermeasures using the finite difference method (FLAC^3D) combined with comparative analysis and typical engineering application at Xingcun coal mine. It is indicated by the analysis that the simple symmetric support systems used in the past led to destruction of the deep rock roadway from the key zone and resulted in the deformation of asymmetric floor heave in the roadway. Suitable reinforced support countermeasures are proposed to reduce the deformation of the floor heave and the potential risk during mining. The application shows that the present support technology can be used to better environmental conditions. The countermeasures of asymmetric coupling support can not only effectively reduce the discrepancy deformation at the key area of the surrounding rock mass, but also effectively control floor heave, which helps realize the integration of support and maintain the stability of the deep rock roadways at Xingcun coal mine.     

Deformation control of asymmetric floor heave in a deep rock roadway:A case study

In order to control asymmetric floor heave in deep rock roadways and deformation around the surrounding rock mass after excavation, in this paper we discuss the failure mechanism and coupling control c...     

穿线钢管防腐工艺自动化生产线的研究

针对穿线多管现行涂锌工艺存在的问题和管内防腐层喷涂工艺及ＰＬＣ控制自动喷涂机进行分析和研究,提出用高能浸涂,工艺取代镀锌工艺和管内喷涂工艺的设想。