铜辉矿业水文地质调查及分析

为了保证铜辉矿业下一步开采的安全性,开展水文调查,分析含水层与隔水层特征,各含水层间与地表水和地下水的关联,对勘查区进行了岩溶含水岩组富水性水文地质分区。研究结果表明：岩溶含水层沿走向方向均富水,完整岩层隔水性能较好,但部分有斜节理发育,隔水效果降低。各含水层之间和地表水之间存在一定补给关联,地下水含水层的补给、径流、排泄条件较差,地下水运动相对滞缓。矿段中、西部岩溶含水层富水性中等。水5孔以西岩溶含水层有泉出露,富水程度较高。能够为矿山安全生产过程中进行防治水工作提供技术支持。     

矿井开采后水文地质特征及水害防治技术研究

水害是影响矿井安全生产的主要因素,以区域水文地质概况为基础,分析了矿井开采后水文地质特征,主要是地形地貌、水文,含水层、隔水层,地下水补给径流排泄及涌水量的变化,对矿井充水因素及矿井防治水措施进行了研究。研究为矿井水害治理提供了技术支持。     

南泥湖露天矿区采场水力联系及矿坑涌水量预测

为了查明南泥湖露天矿区采场范围内水力联系及矿坑涌水量,分析了含水层类型及其富水性特征,地下水补给、径流、排泄条件,地下水的基本特征等,基于此,采用长期水文监测、示踪试验及水化学分析等方法,研究了大气降水、地表水、地下水及矿坑涌水之间的水力联系及相互转换关系;并分析了露采矿坑的涌水因素以及预测了露采矿坑涌水量,主要包括矿坑大气降水补给量、地表径流量和地下水补给量。研究为后期水文地质监测以及地质灾害防治提供了技术支持。     

Dewatering concepts at Zambian Copperbelt Mines

During the financial year 1992/93, Zambian Consolidated Copper Mines Ltd (ZCCM) Ltd pumped a total of 263 million tonnes of water from its various mining operations. During the same period the Company produced 23 million tonnes of ore, giving a water to ore ratio of 11.4 tonnes of water per tonne of ore produced. Hydrostatic pressures interesected in underground boreholes ranged upto about 5MPa. Against this background the dewatering techniques that have been practised on the Copperbelt at ZCCM’s mines are reviewed. The methods include the surface exclusion of water, interception of water, simple drainage, breakthrough methods, dewatering drilling, grouting isotope analysis and computer modelling. The surface exclusion of water includes the use of canals and pipelines to carry water over hydrological hazard zones, herringbone ditches to speed up run-off, stream gauging to locate hydrological hazard zones and weirs to quantify flow rates, and the judicious geological siting of dams and other surface water structures. Interception methods basically revolve around the concept of interception of the potential mine drainage at the extremities of the mines in order to ensure that the cone of dewatering is lowered before it intercepts the main mining areas. Simple drainage is the mining of drives into aquifers at reduced hydrostatic pressures in order to drain specific aquifers. Breakthrough methods also involve the mining of drives into aquifers but in a more controlled manner than in simple drainage. In this instance drives are mined directly into aquifers utilising watertight doors or puddle pipes to protect the main mine workings. Dewatering drilling is the most widely used method of dewatering used on the Copperbelt. It may be conveniently divided into surface and underground dewatering boreholes. Surface dewatering boreholes may be either pumped, utilising borehole pumps, used for piezometric measurements, or used in open pit situations to drain aquifers under hydrostatic pressure. Underground dewatering boreholes are the most widely practised method of dewatering on the Copperbelt and involve the drilling of boreholes into aquifers, in order to lower the hydrostatic head in a particular aquifer. A number of different techniques are discussed. Grouting to exclude the inflow of water into mines has long been known as a method of groundwater exclusion. The uses of cementious grouts and resin grouts are discussed. Isotope analysis has been used at Konkola Division to give indications of both the age and possible origins of the Konkola groundwaters. Computer modelling utilising modflow software has been used at Konkola Division to predict drawdown of the hydrostatic head in a number of different mining scenarios. A changeover from caving mining methods to mining methods involving the use of backfill should permit certain mines to effect major cost savings with regard to dewatering costs. The implications of this change in mining methods is discussed. Environmental aspects of mine drainage from ZCCM’s mines is addressed and the lack of an acid mine drainage problem briefly discussed.     

Mathematical modelling for estimation of minewater inflow to a surface mining operation

Estimation of water inflow to a surface mining operation is a necessary requirement for mine drainage design. The water in a shallow surface mine may originate solely from a surface source and from the atmosphere in the form of precipitation. Water in deep mining excavations below the groundwater table may originate from a surface source or as atmospheric precipitation as well as from the groundwater system. Inflow of surface water to a mining excavation can be predicted by hydrological balance investigation of a mining catchment. The paper briefly describes the hydrological cycle of a mining catchment together with the technique of estimating inflow from a surface source. The groundwater inflow to a mining excavation is mainly a consequence of the interaction of groundwater system, hydrogeological characteristics of the rock mass and the mining geometry. The water inflow regime is determined by the incision of one or more aquifers by the mining excavation and the relative hydrogeological characteristics of the various aquifers. The paper identifies various possible flow regimes in the vicinity of mining excavation. The groundwater inflow can be estimated by one of the following techniques:

- Equivalent flow approach

- Two-dimensional flow equations

- Numerical techniques incorporating the Finite Element Method, Finite Difference Method or the Boundary Element Method.

     

Using a Water Balance to Determine the Source of Water in the Flooding Underground Mine Workings of Butte

Abstract.  Nearly 10,000 miles (16,000 km) of underground mine workings began flooding on April 22, 1982 when the large pumps used to dewater the mines of Butte, Montana were shut off. In the first few months, water levels in the workings rose hundreds of meters. Flooding continues to this day at a slower rate, nearly 25 years later. An early evaluation of the water chemistry in the flooding mines suggested that the initially poor water quality was the result of flushing of a reservoir of stored acidity and metals. However, a detailed water balance for the Berkeley pit, underground workings, and associated mining features suggests an alternative explanation. During the early period of mine flooding, acidic surface water from the deactivated heap leach operations and nearby acid rock drainage were routed into the empty Berkeley Pit, and thence drained downward and outward into the underground mine workings, causing widespread degradation of water quality in the underlying workings. After 21 months, the hydraulic gradients in the system reversed, causing a change in the direction of ground water flow and a gradual improvement in water quality of the mine shafts.     

Geochemistry,Hydraulic Connectivity and Quality Appraisal of Multilayered Groundwater in the Hongdunzi Coal Mine,Northwest China

This study assessed the geochemistry and quality of groundwater in the Hongdunzi coal mining area in northwest China and investigated the mechanisms governing its hydrogeochemistry and the hydraulic connectivity between adjacent aquifers. Thirty-four groundwater samples were collected for physicochemical analyses and bivariate analyses were used to investigate groundwater quality evolution. The groundwater in the mine was determined to be neutral to slightly alkaline, with high levels of salinity and hardness; most samples were of SO₄·Cl–Na type. Fluoride and nitrate pollution in the confined aquifers were identified, primarily sourced from coals. Natural geochemical processes, such as mineral dissolution, cation exchange, and groundwater evaporation, largely control groundwater chemistry. Anthropogenic inputs from agricultural and mining activities were also identified in both shallow unconfined aquifers and the deeper confined aquifers, respectively. It was determined that the middle confined aquifer has a high hydraulic connectivity with the lower coal-bearing aquifer due to developed fractures. Careful management of the overlying aquifers is required to avoid mine water inrush geohazards and groundwater quality deterioration. The groundwater in the mining area is generally of poor quality, and is unsuitable for direct human consumption or irrigation. Na⁺, SO₄^2?, Cl^?, F^?, TH, TDS, NO₃^?, and COD_Mn are the major factors responsible for the poor quality of the phreatic water, while Na⁺, SO₄^2?, F^?, and TDS are the major constituents affecting the confined groundwater quality. This study is beneficial for understanding the impacts of coal mine development on groundwater quality, and safeguarding sustainable mining in arid areas.     

Impact of coal mining on mine water quality

The coal mining industry has to dispose of millions of litres of water every day. This water forms main source of various water supplies in the thickly populated coalfields. In this study, water samples from major coalfields were collected and analysed in an attempt to reflect the impact of mining on water quality in these areas. Various physico-chemical characteristics of mine waters as analysed include pH, alkalinity/acidity, specific conductivity, hardness, total solids, sulphate, chloride iron and trace materials. This investigation reveals that mining activity, markedly pollute the mine waters. Mine waters are of highly complex nature and of widely varying composition. These are nearly neutral, alkaline, mildly acidic and highly acidic in nature. Special emphasis on water quality deterioration due to acid mine drainage which result in significant concentration levels of tract (toxic) metals, is given. A classification of these mine waters is also made.     

Reclamation and decontamination of metalliferous mining tailings

Parts of Britain have large accumulations of metalliferous tailings derived from mining in the 18th, 19th and 20th centuries. These tailings were never subject to land reclamation schemes at the time of mining and are situated very close to water courses. They cause considerable environmental damage in terms of contamination of soils, dust blow and pollution of water courses and groundwater. In some parts of the country mine drainage is a major part of river pollution. In recent years, particularly in Wales, efforts have been made to “clean up” these sites. This has involved using techniques to isolate and contain the spoil, diversion of water courses, and the installation of water treatment facilities and drainage and the establishment of a vegetation cover. Research is also being initiated to investigate ways of decontaminating these metalliferous spoils as an alternative to using covering systems to reclaim them.     

Groundwater Geochemical Variation and Controls in Coal Seams and Overlying Strata in the Shennan Mining Area,Shaanxi, China

Water resource conservation and ecological protection are key coal mining issues in northern Shaanxi Province and the Yellow River Basin. Revealing the characteristics and variation patterns of groundwater quality in the coal series and its overlying aquifers can provide a geological foundation for solving or optimizing these issues. Taking the Zhangjiamao coal mine of the Shennan mining area in northern Shaanxi Province, western China, as an example, water samples were collected for analysis from the: quaternary strata, weathered bedrock, burnt rock, coal series, and coal seam. Test parameters included conventional ion concentrations, total dissolved solids (TDS), and pH. Key water chemistry indicators such as oxidation/reduction index (ORI) and groundwater chemical closure index (GCCI) were used to explain the water quality differences. The Quaternary water, burnt rock water, and weathered bedrock water were dominantly the Ca–HCO₃ type, the coal series water (Yan’an Formation) was dominantly Ca–HCO₃ and Na–Cl types, and the coal seam water was dominantly Na–Cl type. From the shallow groundwater to coal seam water, dissolution and leaching gradually decrease and degree of retention gradually increases. Coal seam water was characterized by high TDS, high GCCI, and low ORI, reflecting a closed hydrogeochemical environment and moderate sulfate reduction. Leaching, salt accumulation, sulfate reduction, and cation exchange jointly control the groundwater chemical characteristics and evolution of the coal series and its overlying aquifers. Salt accumulation and cation exchange reactions of the stagnant coal seam water in the arid and semiarid climates and shallow buried conditions result in increased mineralization; the water quality is vastly different from that of the overlying aquifers, which are dominated by leaching. Groundwater circulation in the coal series and coal seam are of the infiltration–retention type, and the overlying aquifer of the coal series are of the infiltration–runoff type. A comprehensive hydrogeological model was constructed of the Middle Jurassic coal series and its overlying aquifers in the area. The results of this study have implications for the identification of mine water influx sources in the Shennan mining area, and the understanding of controls on the groundwater geochemical variation in Jurassic coal field of western China.

     

Life cycle assessment of the desulfurisation flotation process to prevent acid rock drainage: A base metal case study

The long-term generation of acid rock drainage (ARD) from sulfide-bearing mine waste is a major environmental liability for the mining sector. Previous studies have demonstrated that these ARD risks can be effectively avoided, and resource recovery simultaneously improved, through the pre-disposal removal of sulfide minerals, by means of flotation.This study uses life cycle assessment to evaluate the broader environmental consequences of incorporating a desulfurisation flotation unit for the pre-disposal treatment of a base metal sulfide tailings wastestream. The desulfurisation flotation process is shown to result in a significant decrease in human toxicity, eco-toxicity, urban land occupation and natural land transformation impacts, but an increase in climate change, fossil fuel depletion and terrestrial acidification impacts. Desulfurisation flotation also offers the opportunity for improved recovery of valuable resources, such as water, residual metals and sulfur. An expanded system boundary would, however, be required to capture the environmental benefits of upstream and downstream utilisation of recovered resources. The study also highlighted the deficiencies of current life cycle impact assessment tools, in terms of their ability to adequately assess the environmental impacts associated with solid mineral wastes. These deficiencies and shortcomings will be the subject of further studies.     

Numerical Simulation of Mine Water Inflow with an Embedded Discrete Fracture Model: Application to the 16112 Working Face in the Binhu Coal Mine,China

Properly accounting for the effect of heterogeneity of aquifers and accurately predicting mine water inflow during the mining process is still a challenging problem in China. We developed a stochastic modelling methodology that considers a large range of possible multi-scale fracture configurations and heterogeneous porous rock to predict mine water inflow close to the observed data. The coupled discrete fracture–rock matrix models were built for the Binhu coal mine 16,112 working face with the Monte Carlo method. The models were solved using the embedded discrete fracture model to calculate groundwater inflow from the aquifer beneath the coal seam floor. The calculated results and the observed groundwater inflows in the field agreed well. Sensitivity analysis indicates that groundwater inflow increases with increased fracture length and fracture density. The effect of natural fractures introduces a large uncertainty for the models, due to the existence of long fractures that could act as conduits between the Ordovician limestone and no. 14 aquifers. The results highlight the importance of multi-scale fractures on modeling and simulating flow in the mine area.

     

Mine water quality deterioration due to acid mine drainage

Water quality deterioration due to acid mine drainage is of concern in the northeastern coalfield of India as the water in this area is severely polluted. The mine drainage water emanating from various collieries are highly acidic in character and contain high hardness, sulphate, total dissolved solids and iron coupled with low pH values—which further results in contamination of trace (heavy) metals at significant levels. Trace metals are highly toxic and undesirable and are injurious to human health. These acidic waters are also typically hard in character because of iron sulphate content rather than common Ca?Mg bicarbonate type hardness.     

南方某离子型稀土矿山的土地复垦

为了更好地开展南方离子型稀土矿山损毁土地的复垦工作,依据土地复垦方案编制规程要求,以某离子型稀土矿山为例,介绍了该类型矿山土地损毁的特点,总结了复垦时序、表土资源剥离和堆存、原地浸矿采场集排水工程、风险金等复垦工程设计特点,并对已损毁土地不同复垦措施进行对比。可以看出,离子型稀土矿山土地复垦方案主要包括拟损毁土地和已损毁土地2大部分。拟损毁土地方面,应结合原地浸矿工艺特点,考虑采场母液渗漏对植物根系和地下水的影响,重视采场集排水工程的修建,增加风险金的提取;已损毁土地方面,应结合矿区废弃地现状,重视已损毁土地损毁特点、程度、面积、立地条件等调查工作。     

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.     

徐楼铁矿地面沉降成因及预测

为深入分析徐楼铁矿地表沉降成因,预测矿区地面沉降规律,首先分析了该矿一期采矿工程地面沉降的发育现状,然后从围岩应力场、矿体赋存条件、矿区地下水疏排、区域地质构造、采空区充填等方面对矿区地面沉降成因进行了讨论,最后基于矿区现有的工程地质资料及地面沉降监测资料,采用概率积分法和曲线拟合法预测了矿区地面沉降范围及沉降量,并对预测结果进行了分析。结果表明：①该矿区地面沉降是围岩应力场、矿体赋存条件、矿区地下水疏排、区域地质构造、采空区充填等因素共同作用的结果;②概率积分法预测的采空沉陷区面积约0.22 km2,矿区主井、副井、风井及采矿工业场地大部分位于预测采空塌陷区内,可能引发的采空区塌陷灾害危险性较大;③曲线拟合结果与实测数据较吻合,可较好地反映矿区沉降的实际情况,精度较高。上述结果进一步表明：近年来,矿区地面沉降量和沉降范围呈剧烈加速的趋势,实测沉降影响范围及沉降量远小于预测结果,可见地表仍有一部分建（构）筑物及设施位于预测沉降范围内,此外,随着二期采矿工程的全面展开,矿区地面沉降量及沉降范围在短期内仍会继续增大。     

多源矿井水质量分区与“分质”利用研究

矿井水“分质”利用是解决矿区水资源短缺、保护矿区生态、防治水污染的重要途径。为实现矿井水综合利用,通过改进层次—可变模糊集模型对敏东一矿多源矿井水进行质量分区,并提出相应的“分质”利用思路。研究结果表明,敏东一矿充水水源水样中Ⅰ、Ⅱ含水层水质较好,第四系含水层和Ⅲ含水层中存在COD和Fe、Mn、Zn超标,由于采煤活动和人为活动的影响,使采煤过程、水仓和排水沟水样中多数指标超标且变动较大;利用模型得到间接充水水源中第四系含水层水质为Ⅱ级,Ⅰ、Ⅱ含水层为Ⅰ级,直接充水水源为Ⅱ级,采煤过程中采空区和巷道为Ⅲ级,工作面为Ⅳ级,水仓和排水沟均为Ⅳ级。质量分区中,Ⅰ类区水质较好,可简单消毒后利用;Ⅱ类区个别指标超标,需针对性处理利用;Ⅲ类区受采煤活动影响较小,较多指标超标,需针对性或深度处理利用;Ⅳ类区受采煤活动影响较强,多指标超标且变动较大,需深度处理利用。     

榆神府矿区含水层富水特征及保水采煤途径

榆神府矿区地处毛乌素沙漠与黄土高原的接壤地带,生态环境脆弱,水资源匮乏,区内各主要含水层分布与富水性不均,含水层富水性及矿井涌水对煤矿生产影响差异较大,因此矿井水资源的综合利用与含水层的有效保护对煤矿生产与地区生态建设意义重大。通过分析萨拉乌苏组、烧变岩、风化基岩层等各主要含水层的形成、分布及富水特征,结合矿井首采煤层上覆基岩厚度与矿井目前涌水量情况,将区内生产矿井及待规划区域从"水资源保护与矿井水利用"角度划分为水量贫乏型、水量较丰富型、水量丰富型及地表水体型4种类型,并根据不同类型的分布特征进行了分区。在此基础上,针对不同的水资源保护与矿井水利用类型,分别提出了采空区存储净化、工业利用、农业灌溉、湿地建设和人工湖泊等具体的水资源保护与矿井水利用途径和措施。讨论了"保水采煤"的科学内涵,认为"保水采煤"的基本措施应当包括保护浅部主要含水层和矿井水资源利用两部分,即将"保水"与"用水"相结合,拓展了"保水采煤"的科学含义;建议在矿井规划时,应综合考虑开采损害影响与环境自身修复能力,在满足能源开采经济利益的同时,保证生态环境不发生质的破坏;提出了利用经济效益"反哺"当地生态和"绿色经济"建设的一点猜想,为矿区未来的规划建设提供了一定的参考意义。     

司家营铁矿项目建设及采选系统介绍

介绍了河北钢铁集团矿业有限公司司家营铁矿自然概况、资源分布及项目规划建设情况,重点介绍了司家营铁矿一期工程采矿工艺、选矿工艺,供水、供电等公辅设施,以及废石填海造地、尾矿库易址采煤沉陷坑等情况。     

Development of the Sleeper Pit Lake

Abstract.  The Sleeper open pit gold mine operated from the mid-1980s through the mid-1990s. Operations were mostly sub-water table and extensive dewatering was required to lower groundwater levels by 180 m. Dewatering flows peaked at 930 L/s, with most flow contributed from an alluvial aquifer. After completion of mining, the pit was rapidly filled with water pumped from the alluvial aquifer to reduce the exposure time of sulfide wall rocks and waste rocks in the ultimate pit. The pumped alluvial groundwater provided a large volume of low total dissolved solids (TDS), high alkalinity water that controlled the early chemistry. The rising lake waters were amended with lime to buffer excess acidity contributed to the lake from reactive pit wall rocks during submergence. The pore water contained in submerged waste rock at the base of the pit was elevated in TDS and subsequently of higher density that the lake water. The density contrast and waste rock location limited contributions of waste rock pore water to the main body of the lake. Some stratification of the early lake occurred, with shallow water characterized by higher pH, low dissolved metals, and sulfate; deeper water had lower pH and higher dissolved metals and sulfate. The reservoir of alkalinity in the shallow layer mixed with the deeper waters and created a stabilized lake with a homogenized column that exceeded water quality expectations. Current water quality meets all Nevada primary drinking water standards with the exception of sulfate, TDS, and manganese, which are slightly elevated, as predicted. Chemistry has remained stable since development of the initial lake.