Geochemical and Mineralogical Characterization of a Pyritic Waste Pile at the Anjir Tangeh Coal Washing Plant, Zirab, Northern Iran

Coal washing at the Anjir Tangeh plant, in Zirab, northern Iran, has produced more than 1.5 Mt of coal wastes. These waste materials were geochemically and mineralogically characterised to guide development of an appropriate remediation scheme. Three vertical trenches up to 4 m deep were excavated from the coal waste pile surface and 25 solid samples were collected at 0.5 m intervals. The samples were analysed for total concentrations of 54 elements, paste pH, SO ₄ ^?2 , CO ₃ ^?2 , and HCO₃ ^?. The lowest pH values were measured at a depth of 0.3 m. The upper portion (1 m) of one profile was moderately oxidised, while oxidation in the other two profiles did not extend more than 0.8 and 0.5 m beneath the pile surface. The waste piles have low acid-producing potential (15–21.87 kg CaCO₃/t) and high values of acid-neutralizing potential (0.06–96.2 kg CaCO₃/t). Fe, Al, S, Na, Mn, Pb, Zn, Cd, and Ag increased with increasing depth, while Mo, Sr, Zr, and Ni decreased with increasing depth. The results show pyrite oxidation at depth and subsequent leaching of the oxidation products. Mn, Zn, Cu, Pb, Ag, and Cd are the most important contaminants of concern at this site.     

Prediction of Pyrite Oxidation in a Coal Washing Waste Pile Applying Artificial Neural Networks (ANNs) and Adaptive Neuro-fuzzy Inference Systems (ANFIS)

Two models were evaluated as alternative methods for predicting pyrite oxidation in the Alborz Sharghi coal washing waste pile (in northeastern Iran). The first model applies a ‘feed-forward artificial neural network (ANN) with 4-7-1 structure’. The model uses depth, initial remaining pyrite fraction, mole fraction of oxygen, and annual precipitation as input parameters and returns the remaining pyrite fraction in the related depth of the pile as its output. In the second model, an adaptive neuro-fuzzy inference system (ANFIS), which uses generalised bell membership functions and the Takagi–Sugeno-type fuzzy inference system, was applied with the same input–output parameters. The correlation coefficient, root mean squared error, and average absolute relative error for the training stage of the ANNs were 0.81, 0.169, and 0.12, respectively, while the values for ANFIS were 0.91, 0.091, and 0.078, respectively. Comparison of the correlation coefficients and the error parameters revealed that both models successfully predicted remaining pyrite fraction from various depths of the pile. However, ANFIS was found to be more reliable and more accurate.     

新建煤矿矸石山自然发火的数学模型及其模拟分析

煤矿矸石山自燃是导致矸石山自燃爆炸灾害事故和造成矿区周围环境污染的主要原因。将矸石山看作一大体积多孔介质,运用多孔介质流体渗流理论并结合达西定律和渗流连续性方程,建立了煤矿矸石山自然发火的数学模型,并在此基础上对新建煤矿运输区矸石山内部漏风风流的流动规律进行了研究,提出了矸石山自然发火的防治途径。     

煤矿运输新型线摩擦皮带机研究及应用

该文简要介绍了协庄煤矿长距离运输的现状,并详细阐述自行设计的线摩擦皮带机装置的特点及性能。     

煤块瓦斯解吸渗流数学模型及残存瓦斯量数值解法

本文以多孔介质渗流理论为基础,建立了煤块瓦斯解吸渗流微分数学模型,给出了残存瓦斯量的数值计算法,并与实测值进行了对比验证。     

某矿实体煤巷锚杆支护数值模拟及工程应用

巷道锚杆支护是岩土与结构耦合的工程问题,与地应力、围岩力学性质、锚杆支护结构等因素有关。使用ANSYS有限元数值模拟软件,开发出三维采准巷道锚杆支护辅助设计系统,对煤巷锚杆的支护作用机理进行了分析计算,主要研究了类似条件下锚杆支护对巷道变形以及巷道周围应力场和位移场的影响,分析了锚杆支护在给定条件下的作用规律。将该模拟结果运用到某煤矿2395实体煤巷锚杆支护工程实际中,得到了较好的支护效果,为进一步推广应用提供了经验。     

A Hydro-Economic Model for Optimizing Management of Mine Water: A Case Study in the Suancigou Coal Mine,Northwestern China

Mine Water and the Environment - Comprehensive analysis of hydrogeological conditions at a typical coal mine in northwestern China allowed us to establish a groundwater numerical model, which we...     

Simultaneous Removal of Copper, Zinc, and Sulfate from Coal Mine Waste in a Laboratory SRB Bioreactor Using Lactate or Ethanol as Carbon Sources

The feasibility of inoculating coal mine waste piles with sulfate-reducing bacteria (SRB) to prevent the production of acidic leachates containing sulfate and metal contaminants was evaluated in batch and column bioreactors. The results showed that SRB growth and activity could be attained in the presence of acidic (pH 4.5) coal mine waste using lactate or ethanol as a carbon source, while no obvious growth was found at pH <3.5. Inoculation of coal mine waste in batch reactors with lactate or ethanol as a carbon source resulted in efficient neutralization and high removal of sulfate and metals. Similar results were attained in dynamic-flow columns inoculated with SRB. SEM-EDS analysis of the precipitates showed iron sulfide to be the main component. This study indicates that SRB could possibly be used to prevent or limit acidic drainage from coal mine waste piles.     

Predicting the Height of the Water-conducting Fractured Zone Based on a Multiple Regression Model and Information Entropy in the Northern Ordos Basin,China

Predicting the water-conducting fractured zone (WCFZ) height is the key to roof water disaster prevention and environmental protection. Field WCFZ data were collected from 24 working faces of Shendong, Shenfu, Yushen, and Yuheng mining areas in the northern Ordos Basin. A fitting formula was obtained by a multiple regression model and the weight of each factor was calculated by information entropy theory, allowing a prediction of the WCFZ height in the area. The formula was improved by applying a safety factor of 1.33, which met the 95.8% reliability requirements of the samples. Finally, the 31,114 working face of the Jinjie coal mine was selected as a case study. The spatial characteristics of the WCFZ in the study area were analyzed using a geographic information system (GIS) and the WCFZ height was measured using borehole TV. The predicted value was 49.6 m and the field measured value exceeded 42.4 m, making the model-predicted value much closer that predictions calculated with other empirical formulas. The results indicate that this method quantitatively predicted the WCFZ height in the study area and enabled the WCFZ height in the study area to be visualized with GIS technology. It is an effective tool for analyzing and predicting the height of the WCFZ and for preventing mine water inrush.

     

Hydrogeochemical Processes and Inverse Modeling for a Multilayer Aquifer System in the Yuaner Coal Mine,Huaibei Coalfield,China

Coal mining can dramatically change hydrogeological conditions and induce serious environmental problems. Fifty groundwater samples were collected from the main aquifers in the Yuaner coal mine (Anhui Province, China). The results show that the main hydrogeochemical processes in the mine include dissolution, precipitation, pyrite oxidation, desulfurization, and cation exchange. The Neogene porous aquifer is affected by groundwater flow conditions; its main hydrogeochemical processes are dissolution of carbonate minerals and gypsum, and cation exchange. The Permian coal measure’s fractured sandstone aquifer was confirmed to be controlled by the region’s geological structure; its main hydrogeochemical processes are desulfurization and cation exchange. The Carboniferous Taiyuan limestone aquifer was determined by both groundwater flow conditions and regional geological structure; its main hydrogeochemical processes are dissolution of carbonate minerals and gypsum, pyrite oxidation, and cation exchange. Additionally, hydrogeochemical inverse modeling of the groundwater flow path confirm the hydrochemistry results and principal component analysis.

     

平原地区采煤沉陷积水计算模型构建与影响分析

为解决东部平原矿区采煤沉陷积水量的计算与分析问题,创新性地将GIS水文分析应用于沉陷积水研究,构建了采煤沉陷区积水计算模型。以洸府河流域为例,计算得到该流域2009年及2015年采煤沉陷影响汇流面积分别为276.0 km²和1 091.4 km²,影响的大气降水汇流量为0.58亿m³和2.29亿m³,实际滞留水量为286.7万m3和556.2万m3。采煤沉陷积水对于流域的原始自然径流和水循环都有很大程度的破坏,构建的沉陷积水计算模型可为矿区沉陷积水治理与水资源保护利用提供技术支持与理论指导。     

Water Inrush Modes Through a Thick Aquifuge Floor in a Deep Coal Mine and Appropriate Control Technology: A Case Study from Hebei,China

Mine Water and the Environment - Water inrush disasters caused by confined aquifers under high pressure below the mine floor are a major problem in China, restricting the safe and efficient mining...     

Evaluating Induced Fractures Between a Large Artificial Lake and an Aquifer-Coal Seam System: A Case Study in Tangshan Coal Mine,China

The hydrogeology of the Tangshan coal mine is extremely complicated. There are at least 20 major faults, with the offset exceeding 50 m. A large artificial lake was created where mining-induced subsidence occurred; it was filled with groundwater pumped from the adjacent aquifers near the coal seams. In addition, there are two nearby rivers that are also believed to have significant groundwater and surface water interactions. Both the river system and the large lake could be a potential threat to a new mining operation in the deep no. 5 coal seam. An in-situ hybrid packer system was designed to measure the thickness of the fracture zone and a 3-D hydrogeological model of the coal seam, associated aquifers, artificial lake, and surface water was established to simulate the groundwater flow field to evaluate the potential impact of induced fractures between the lake and the aquifers and coal seams. The results indicated that the lake has an insignificant impact on the aquifers and coal seams, though it does influence the shallow quaternary aquifer in the study area. Further study is suggested to monitor the groundwater and surface water interactions between the lake and the shallow aquifer system.