Engineering Closure of an Open Pit Gold Operation in a Semi-Arid Climate

Along with material characteristics and geometry, the climate in which a mine is located can have a dramatic effect on the appropriate options for rehabilitation. The paper outlines the setting, mining, milling and waste disposal at Kidston Gold Mine's open pit operations in the semi-arid climate of North Queensland, Australia, before focusing on the engineering aspects of the rehabilitation of Kidston. The mine took a holistic and proactive approach to rehabilitation, and was prepared to demonstrate a number of innovative approaches, which are described in the paper. Engineering issues that had to be addressed included the geotechnical stability and deformation of waste rock dumps, including a 240 m high in-pit dump: the construction and performance monitoring of a “store and release” cover over potentially acid forming mineralised waste rock; erosion from the side slopes of the waste rock dumps; the in-pit co-disposal of waste rock and thickened tailings; the geotechnical stability of the tailings dam wall; the potential for erosion of bare tailings; the water balance of the tailings dam; direct revegetation of the tailings; and the pit hydrology. The rehabilitation of the mine represents an important benchmark in mine site rehabilitation best practice, from which lessons applicable worldwide can be shared.     

Prediction of soil erosion from waste dumps of opencast mines and evaluation of their impacts on the environment

The volume of mine waste rock generated, including tailings from mineral processing activities, is one of the main pollution concerns in the mining industry in general. In the State of Goa (India), the waste rock management is becoming increasingly difficult due to acute space shortage consequent to expanding mining activities. These waste rocks contain acid producing sulphides and high concentrations of heavy metals. In the Goa region, the agricultural fields, nallahs, river beds and creeks are prone to heavy siltation/sediment deposition, which results from soil erosion due to the heavy rainfall this region receives. In view of this erosion and consequent degradation of surrounding environment, this article seeks to estimate the amounts of soil erosion from mine waste rock dumps using the RUSLE model and evaluates the impacts of erosion on the local environment. Based on data interpretation and RUSLE analysis, the trends in soil loss were established under various geo-environmental conditions, such as different slope angles and lengths. This provides a sound basis to plan and implement sound environmental management practices for mine waste rock in the mines of Goa, India.     

掘进巷道粉尘浓度与环境参数的综合分析

针对某金属矿1100斜坡道掘进巷道粉尘浓度过高的实际情况,为找出粉尘浓度过高的原因以及对粉尘浓度的主要影响因素,运用灰色关联分析方法,合理选取与粉尘浓度相关的风速、空气温度、湿度和围岩温度等4个作业环境因素,通过建立粉尘浓度与作业环境因素之间的关系模型,分析了各环境因素与粉尘浓度之间的影响关系程度。结果表明,在4个作业环境因素中,风速是影响掘进巷道粉尘浓度的最主要因素,为该矿井通过提高巷道风速,降低巷道空间空气温度、围岩温度和湿度,进而改善工作环境提供了理论依据。     

某煤矿通风系统智能优化

矿井通风系统是矿井生产系统的重要组成部分,是矿井安全生产的基本保障。构建了矿井三维通风模型和通风智能优化系统,实现了通风参数的自动结算,达到对风速、风量、风压、瓦斯、粉尘及有害气体的在线监测,并可进行反风演练,对提高矿井安全生产、瓦斯、煤尘、火灾的防治,都有重要意义。     

高海拔矿山掘进面长压短抽式通风粉尘分布数值模拟

为了研究高海拔矿山的粉尘污染难题,以西藏自治区某铜多金属矿为工程背景,通过对比试验的方法确定高海拔矿山粉尘颗粒的主要粒径分布范围;根据气固两相流理论,运用FLUENT软件对长压短抽通风除尘系统的效率、最佳压入风量以及最优抽吸比进行数值模拟,并与现场测试结果对比分析。研究结果表明：长压短抽通风除尘系统在1 200 s时基本排出全部粉尘,压入风量取150 m3/min,抽吸比取0.9最为合适,同时数值模拟结果与现场实际变化规律基本一致,除尘效率达到90%以上,此时巷道内的粉尘质量浓度保持在0.5 mg/m3以内。     

某铅锌矿巷道型采场粉尘扩散特性研究

为了掌握局部通风的长抽长压式巷道型采场在凿岩作业时粉尘颗粒扩散特性研究,获取合理的通风除尘参数,以某铅锌矿巷道型采场为研究背景,依据相似理论基本原理,建立巷道型采场相似实验模型。对采场模型及现场进行风流特性试验,研究了不同工况点下采场风流变化特性;不同风速下采场模型粉尘浓度及分散度试验;分析不同工况点对粉尘浓度及分散度影响程度。结果表明：采场流场在不同风速下,当粉尘颗粒从模型工作面位置进入采场模型后,发现粉尘颗粒粒径大小位移距离会发生明显变化,当工况点风速为0.75 m/s时,工作面粉尘浓度最高为76.4 mg/m3,大部分粉尘颗粒粒径小于10 um,粉尘平均分散度为66.29%,粉尘粒径分散度主要集中在小于2 um,与现场实测结果吻合,说明此工况粉尘颗粒沉降效果最佳。     

尾矿库扬尘综合治理措施的研究

通过对鞍钢所属尾矿库的尾矿粒度、坝高、干滩长度、尾矿排放方式的现状分析和有关科学试验得知,尾矿库扬尘产生主要是由于尾矿粒度细、坝体高风速大、干滩长度过长及多管排放管理不到位所致。尾矿库扬尘治理需采取综合治理措施,其中控制干滩长度及加强多管排放属于生产管理措施;重点地段扬尘治理措施需根据尾矿化学成分、库区供水供电条件及子库运用情况分别采用粉尘覆盖剂、干滩喷淋、干滩绿化等措施进行治理。     

空气幕内气流场的数值模拟与分析

矿用空气幕是一种较好的风流控制技术。但由于现阶段研究还不深入,空气幕的结构设计、参数确定还仅依靠具体的实验分析,具有很大的局限性。采用有限元分析软件ANSYS对矿用空气幕内的空气流动进行仿真分析,得到流体的速度、压力的分布图,为矿用空气幕选择更合理的结构参数提供了依据。     

Inorganic Precipitation of Calcite in Mine Tailings Using Trona

Mine Water and the Environment - Mine tailings pose environmental risks such as dust emission and acid mine drainage (AMD) and also present geotechnical risks, i.e. tailings dam failures. In-situ...     

煤尘表面摩擦风速的计算方法

露天煤场风蚀扬尘量的估算需要确定煤尘表面的摩擦风速.采用数值计算方法,通过对风蚀作用下煤垛流场的计算,得出煤垛各细小表面处的摩擦风速. 当风速为3,3 m/s时,计算得出最大摩擦风速为0,168 m/s,最小为0,063 m/s,平均0,110 m/s.当外界风速增至10,0 m/s时,煤垛各表面摩擦风速随之增大,各表面平均风速为0,294 m/s.计算结果与文献风洞实验值吻合很好,表明其计算的可信性.根据EPA排放模式,以年均风速3,3 m/s,每3 d扰动1次的11 万m2的煤场为例,计算统计结果：煤垛表面起尘率为14,5％,风蚀扬尘量为671,4 t/a,这与实际煤场每年的煤尘风蚀损失量约700 t较为接近.     

A Geotechnical Solution to Reduce Acid Mine Drainage Generation at Recreio Mine

Coal mining is frequently associated with acid mine drainage (AMD) generated by tailings and waste dumps containing sulphide minerals. A practical and economical alternative to minimise AMD generation is to avoid the contact between water and waste dumps using a compacted soil cover. This study evaluates the use of distinct raw materials as cover layers. The study area was an open pit coal mine in the south of Brazil. Geotechnical characterization, physical, chemical and mineralogical analyses were carried out on two different soils from this mine. Hydraulic conductivity tests were performed using Flexible-Wall Permeameter. The results obtained from the hydraulic conductivity tests for two compacted soils suggest their applicability as impermeable layers. Considering the operational aspects at the mine and the characteristics determined for the soils a new construction scheme for the dump site was suggested.     

矿井采运过程典型粉尘防治技术装备研发与应用

针对矿井作业环境粉尘污染日益严重,且现有技术手段防治难、协同弱、效果差等问题,为了从源头上实现矿井粉尘的高效控除,改善矿井作业环境、保障作业人员身心健康,对矿井开采、掘进以及运输等3个典型作业环节的粉尘防治技术装备进行了系统研究开发,提出了金属矿采场多组份水炮泥抑尘、煤矿综采面封闭雾化控除尘、金属矿掘进巷道粉尘净化、煤矿综掘面风雾双幕协同增效控除尘以及矿井皮带运输转载点干雾降尘等高效技术装备体系,结合现场试验和工业应用,对所研发的系列技术装备性能进行了对比分析。研究表明：与普通水炮泥相比,多组份水泡泥对总尘、呼尘的抑尘效果分别提高了90%、80%以上;煤矿综采面雾化封闭控除尘技术装备在现场应用后,工作面平均总尘、呼尘降尘率均大于90%;金属矿掘进巷道粉尘净化系统的除尘效率高达91%以上,净化后的风流能够进入循环通风系统,有效提高矿井风流利用率;煤矿综掘面风雾双幕协同增效控除尘装备对总尘、呼尘的平均降尘率分别能够达到97.78%、98.13%;干雾降尘装置具有良好的降尘效率,在皮带运输转载点的降尘效率达到80.4%,在溜煤眼转载点处的降尘效率达到81.8%。     

综掘工作面压风分流控除尘技术研究与应用

为解决综掘工作面粉尘污染问题,掌握工作面长压通风分流控尘与短抽除尘参数最佳匹配关系,实现最大程度降低工作面粉尘浓度。本文以王家岭煤矿高产尘综掘工作面为研究背景,通过建立CFD计算模型,对比研究综掘工作面不同轴径向出风比的控尘效果,得到有效控尘参数范围,再结合现场实际应用进行验证分析,以此得到最佳控除尘工艺匹配参数。研究结果表明:在增加附壁风筒控尘后,在掘进机尾部形成沿巷道壁螺旋前进的新鲜风流透明风墙,能够将粉尘控制在工作面前部区域;在轴径向出风比为1∶3时,粉尘被控制在前部4 m范围内较小区域,并能满足掘进工作面最低风速要求,对掘进工作面前部粉尘控制作用明显。通过现场对比应用,当轴径向出风比为1∶3时,控降尘效果最佳,司机位置与掘进机尾5 m的总粉尘和呼吸性粉尘浓度可分别降低到26.1 mg/m3和12.7 mg/m3以内,其中控尘效率达到80%以上,总体控降尘效率达93%以上,降尘效果明显,有效缓解综掘工作面粉尘污染,减少了职业危害。     

CO涌出预测数学模型的应用

对于实验室煤样低温氧化实验条件和现场工作面采空区实际既定通风与工作面几何参数条件,可以利用相似准则,建立基于实验条件下采空区CO涌出预测的计算数学模型,并把模型应用到现场工作面。采空区遗煤自燃与采空区漏风量有关,通过FLUENT软件对北皂矿4402工作面采空区漏风流场进行数值模拟,解算出造成采空区遗煤自燃的那部分漏风量,为应用模型较准确的推出现场采空区CO涌出预测的指标范围提供了条件。     

综掘工作面不同截割方式下的最佳风场调控规则

针对目前综掘工作面局部通风方式下,出风口风流状态不能根据实际通风需求进行动态变化,造成巷道内粉尘与瓦斯聚集严重问题,通过最佳风场调控规则分析,以求有效降低粉尘质量浓度和瓦斯体积分数。采用正交试验及流场模拟实验方法分析不同截割方式下风流参数变化对风速、瓦斯及粉尘场分布影响规律,获取大量样本数据,建立风场调控参数与风速、瓦斯及粉尘质量浓度关联关系的初始化决策信息系统,并对其进行K-means算法离散化合并规约处理,建立离散化决策信息系统。基于粒计算和Matlab软件编写了风场调控规则获取的智能算法和参数化程序。利用风场调控规则获取方法和参数化程序分析并建立了陕西神木柠条塔矿S1212胶运巷道综掘工作面的最佳风场调控规则,并利用自主研制的风流调控装置进行了井下测试验证。结果表明:经使用最佳风场调控规则后,巷道内风速在0.25~4.00 m/s及死角区域瓦斯体积分数低于1%的前提下,出风口距掘进工作面最近距离5 m时,回风侧粉尘质量浓度最高降低43%,司机处粉尘质量浓度最高降低38%;出风口距掘进工作面最远距离10 m时,回风侧粉尘质量浓度最高降低15%,司机处粉尘质量浓度最高降低37%。     

高分子抑尘剂对褐煤矿场细颗粒物的抑制特性

为减少褐煤矿场中无组织排放的细颗粒物进入大气,避免其对人体健康、生产安全和大气环境造成严重危害,选取聚丙烯酸乳液、瓜尔豆胶、聚丙烯酰胺和羧甲基纤维素钠4种高分子单体,通过结壳硬度衰减实验筛选得到性能优良的单体瓜尔豆胶。以表面张力和接触角实验比较吐温-20、曲拉通X-100、十二烷基硫酸钠和十二烷基苯磺酸钠 4种表面活性剂溶液对褐煤颗粒的润湿性能,实验发现非离子表面活性剂曲拉通X-100对褐煤粉尘的润湿性能最优。将高分子单体瓜尔豆胶复配以表面活性剂曲拉通X-100,开发得到一种褐煤矿场专用的结壳型抑尘剂。通过抗风蚀性能实验,考察不同单体浓度、不同风速条件对固化层风蚀后颗粒物数量浓度和粒度分布的影响,优选出最佳抑尘剂配方为质量分数0.7%的瓜尔豆胶和0.1%的曲拉通X-100。该抑尘剂可使煤堆表面固化形成具有一定厚度和强度的防护层,10 d后固化层硬度仍可达61.43,能抵抗15 m/s风速侵蚀而不受影响,足以应对北方大风天气。细颗粒物数量浓度降低至3.69×105 cm-3,颗粒物数量浓度峰值出现在0.85 μm左右,低粒径段颗粒物抑制效率总体由30.1%提高至94.4%,粒径0.1 μm左右的细颗粒物抑制效率增幅达到64%。实验结果表明,该抑尘剂对细颗粒物的抑制效果明显,是适合褐煤矿场专用的原材料易得、环保高效的抑尘剂。     

尾矿库大气环境防护距离研究

环境保护部《一般工业固体废物贮存、处置场污染控制标准》（GB18599-2001）等3项国家污染物控制标准修改单公告（公告 2013年 第36号）中指出：应依据环境影响评价结论确定场址的位置及其与周围人群的距离。尾矿库大气环境防护距离的计算,由于其特殊性,目前尚未形成共识。结合某尾矿库项目环评实例,根据尾矿库风洞实验确定尾矿库扬尘源强公式,根据尾矿库扬尘产生特性,对SCREEN3模型进行修正。结果表明：在保持尾矿砂一定含水率（湿度小于1%）及尾矿粒径组成（尾中砂和尾细砂＜30%）情况下,地面贡献浓度达标的距离不会大于1 500 m,折算到尾矿库坝基外侧,确定大气环境防护距离。     

金属矿山爆破微细粉尘云雾除尘机理及试验研究

为降低金属矿山爆破微细粉尘浓度,提出了巷道全断面云雾除尘技术,净化回风流中的粉尘。利用自行设计的雾化实验平台,分析了云雾喷嘴的雾化效果及气压、水压对雾化效果的影响,获得气流量、水流量随气压的变化规律,认为当气压为0.5 MPa,水压为0.2 MPa,水流量为35 L/h,气流量为2.65 m3/h时,云雾雾滴中值粒径D50最小,约6.0 μm。基于云雾喷嘴雾化特性及最佳工况条件,以云雾除尘主机和气水源处置为主体,研发了巷道全断面云雾除尘技术,并在梅山铁矿进行了现场试验。结果表明：爆破落矿后,经云雾除尘装置净化后,回风流中全尘、呼吸尘的降尘效率分别为96.89%、96.04%,表明云雾与粉尘粒径匹配效果好,可有效降低沿风流方向的微细粉尘浓度,提高降尘效率,取得较好经济效益和社会效益。     

Field Study of the Chemical and Physical Stability of Highly Sulphide-Rich Tailings Stored Under a Shallow Water Cover

Highly sulfide-rich (approximately 83 % pyrite), potentially acid-generating mine tailings were sub-aqueously deposited in the Don Rouyn old quarry pit from 1997 to 2000. The site covers approximately 7 ha near Rouyn-Noranda, Quebec. Various in situ measurements and laboratory tests were performed during the summer and autumn of 2008, 2009, and 2010 to: characterize tailings samples; monitor water quality in the final effluent, shallow water cover, and groundwater around the pit, and; study tailings erosion and resuspension. In situ measurements included the vertical profile and spatial distribution of pH, temperature, dissolved oxygen, electric conductivity, and redox potential. Suspended tailings, wind speed, and direction were monitored. Groundwater, cover water, and final effluent water samples were chemically analyzed and suspended sediment concentrations (SSCs) was determined. Physical, mineralogical, and chemical tailings properties were also determined. Results show that the quality of the groundwater, cover, and effluent waters complied with Canadian and Quebec regulations. SSCs were also within regulation limits. No association was found between SSC and hydrodynamic conditions (wind speed, fetch, etc.). Although theoretical calculations indicated a critical wind speed of at least 10 m/s for tailings resuspension, suspended sediment was observed for wind speeds at <10 m/s.     

矿尘凝聚机理及实验研究

通过尘粒起动风速与尘粒粒径的关系的研究,认为可以通过使粉尘颗粒牢固凝聚,生成大尘粒的办法来减少矿井扬尘。通过对尘粒间作用力的比较和分析,肯定了洒水降低井下扬尘的科学性;同时认为用化学方法增大尘粒间的凝聚力,减少矿井扬尘是可行的。