A brief survey of current surface waste disposal practices in the metal mining industry

ABSTRACT

Tailings ponds are a common method of mine waste disposal. Technical as well as environmental aspects of surface disposal of metal mine wastes are briefly reviewed The construction of tailings ponds require a broad range of parameters from geotechnical aspects to effluent treatment and reclamation procedures to be taken into consideration. Working with low grade deposits, which require intense grinding, in addition to the presence of sulphide minerals pose difficulties to the disposal of tailings. Government regulations call for reclamation procedures to be drawn-up prior to the commencement of the mining activities. Generation of Acid Mine Drainage (AMD) is one of the most important problem that a metal mine operation can face. Successful reclamation programs depend on an extensive and detailed water management procedure.

This paper reviews the environmental as well as technical aspects that need to be incorporated into the design and construction of a tailings pond facility to minimize and possibly eliminate potential environmental hazards. Current design of disposal facilities must comply with the existing guidelines and regulations which are also reviewed in this paper.     

Geostatistical economic evaluation of industrial minerals (Malaysia)

ABSTRACT

With escalating production costs and the keen competitiveness of the industrial mineral industry worldwide, the necessity to increase the reliability and decrease the cost for economic mineral evaluation is further gaining prominence. There is thus a need for an efficient and reliable statistical information technology technique for cost optimisation and reliability assessment in the economic evaluation phase. Geostatistics, a collection of statistical information technology techniques, can assist to increase the reliability and optimise the costs for economic mineral evaluation and thus the eventual success of the resource production project. This technical article discusses the application of a well established geostatistical technique in optimising sampling interval costs while still providing acceptably accurate economic evaluation of industrial mineral deposits. The realisation of improved confidence levels using geostatistics assists in decreasing the risks in the planning and management of extracting industrial mineral deposits. Case studies on clay deposits are used to illustrate the practicality in the usage of geostatistics for systematic economic evaluation.     

Errors of estimation due to mineralization and sampling density in massive copper deposits

ABSTRACT

This study is aimed to determine the effects of spatial variation of the grade, and sampling density, on the errors of estimations of the geological and recoverable reserve for typical massive copper deposits.

A spectrum of copper deposits which have log-normal distributions was numerically modelled on a rectangular grid using the simulation method of turning bands. Spherical variograms with six different random to structured variance ratios were used. The mean block grades were estimated for four different sampling densities by employing the kriging method. The two-dimensional dynamic programming algorithm was utilized for determining the ultimate pit limits. The estimation errors were calculated by deducing the actual values from the estimated values.

The magnitude and patterns of errors due to a broad spectrum of sampling density and nugget effect values have thus been determined. It has been found that the percent estimation error for the recoverable net value is much higher than the percent estimation error for the geological reserves, and therefore deserves more attention.     

An application of queuing analysis to the production of aggregates in quarry operations

ABSTRACT

High incidence of failure of quarry operations has been the trend in Nigeria's crushed stone industry for some time now. The problem which emanates from poor planning, design and management cuts across all feizes of operations. Generally, productivity is often maintained at uneconomic levels at the expense of much needed revenue. Uncontrolled production of aggregates often results in the over production of minimally demanded sizes while those that can generate more revenue to keep the industry afloat are in short Supply. As a solution to the above problem, this paper presents the technique of linear programming as an analytical tool for controlling the production of different aggregate sizes with a view to maximizing profit. Specifically, the paper describes the problem formulation technique and discusses the optimum solution obtained from the Application of the resulting model to the problem of an existing quarry.     

An application of goal programming to production planning in the crushed stone industry

ABSTRACT

The problems facing the aggragate stone industry in Zambia such as low capacity utilization, failure to meet customer requirements, unnecessarily high operating costs, poor inventory control practices, heavy borrowing and overall poor economic performance are as a result of subjective decision-making related to production planning. This is also true of the industry in nearly all member countries of the SADDC(Southern African Development Co-ordinating Conference) where quarry closures are not uncommon.

As a solution to the problem of production planning and control in the crushed stone industry, this paper presents results of an application of the goal programming technique to a Zambian case study engaged in the production of limestone powder for the chemical industry. The formulation of a mathematical model for handling multiple objectives is discussed. The goal programming model can be used by management as a strategic decision support instrument.

Results of the study show that over time work is related to the levels of demand for each product as well as the capacity utilization of the plant. The conflicts among the various goals of the short term production plan are identified. The study suggests that goal programming can provide an improved model to solve the problem of production planning in the crushed stone industry.     

Some problems in economical evaluation of phosphate deposits

Abstract

This paper presents an overal procedure adapted presently in China for economical evaluation of the phosphate deposits, and some improvements such as the Triangular Berinstein-Bezier patches Bmooth interpolation method used to creat the real geometrical deposit model and to calculate the mineral reserve, and the objective programming for determing the optimal grade and the feasible mine capacity etc. A case stud; of Yingping phosphate open pit mine (invested by the World Bank) is also included.     

Variable zone modeling – A different approach to ore deposit modeling

Abstract

Geology and separation of ore and waste are two fundamental factors in modeling epigenetic deposits. Epigenetic deposits are those deposits where there is a time lag between the deposition of the ore and the host rock. Geologic features such as lithology, facies, and faults are important contributing factors in ore deposition and should be taken into consideration during data categorization and modeling. Separation of ore and waste should-be handled at the block level. Even though the conventional block modeling technique is claimed to take geology into consideration, this is not accomplished to the extent necessary to produce a representative model and to take advantage of, all the available information. A new modeling technique developed by MK-Environ-mental, called “variable zone modeling” (VZM), takes these geologic features into consideration during data categorization and continues using related information throughout the modeling process.     

Application of a knowledge- and geographical information-based system to the environmental impact assessment of an opencast coal mining project

ABSTRACT

Environmental impact problems are assessed in two steps: scoping exercises (qualitative assessment) and technical assessment (quantitative). The scoping exercises use stored expertise to identify the source of environmental problems and then to analyse the propagation of pollutants and their impact on surrounding areas; when a significant adverse impact is identified, the system provides mitigation advice. Scoping exercises can be conducted repeatedly to assess the effects of different mitigalion measures and/or to assess properties in different locations. At the same time the scoping exercise gathers information that is subsequently used for the technical assessment. The technical assessment uses numerical models of pollutant transmission, together with a geographical model of the mine and surrounding area, to quantify impacts in neighbouring, environmentally sensitive areas. The results of the overall environmental impact assessment are presented as an environmental impact statement in text format and as geographical images.     

Comparison of tripper-spreader combinations

ABSTRACT

In future, the volume of overburden to be dumped will further increase as mining operations have to go down to greater and greater depths in order to expose the mineral deposits to be extracted in open pit mining.

For this reason, the selection of the correct spreading system is becoming increasingly important. Thus, an optimal tripper-spreader combination has to be selected with regard to the actual dumping procedure and the geometry of the dump crosssection.

In order to guarantee economical mining of mineral deposits, despite the increasing costs of overburden removal, the machine system selected must also be examined with regard to its costs, operational safety and availability.

Because of the complexity of the subject matter and the limited size of this paper, this is a contribution only to give a brief overview of the machines more commonly combined as systems and to present their most significant features in terms of type, method of operation, mass and cost effectiveness.     

兖州煤田采矿影响下水环境演变研究

以兖州煤田1990～2018年4期遥感影像为数据源,利用改进的归一化水体指数方法(MNDWI)对兖州煤田水体信息进行提取,对兖州煤田水体演变进行时空分析。基于景观生态学方法选取斑块数量、景观形状指数、面积加权分维数、平均斑块面积等指标,从破碎化情况、形状变化及人为干扰情况等方面对兖州煤田水体演变进行定量化研究。结果表明,采煤活动导致塌陷水体面积不断增加,从1990年的214.38hm2增加到2018年的2 717.73hm2,增长了近10倍;水体形状日趋不规则,受人为活动特别是采矿活动的干扰加强;水体斑块破碎度降低,连续型增强;水体斑块形状越来越复杂,受采矿活动影响程度增大。     

Using dynamic programming for aggregating cuts in a single drillhole

Abstract

In planning a mine with layered deposits one roust decide what to mine as ore or waste. Because there are minimum widths for waste and ore cuts, the decision for a depth interval depends on the ore quality of neighboring intervals. We present a dynamic programming approach that optimizes the cuts for a single drillhole from which the ore qualities are evaluated. We implement a trial version using Lotus 123 to illustrate the properties of the solution.     

铜矿床领域本体的构建方法研究

我国铜矿成矿地质条件较好,但已探明的铜矿资源还不能完全满足国家建设的需要。按知识结构组织地质勘查资料可以有效管理和检索铜矿相关的地质资料和文献,但构建矿产资源领域本体的方法尚在探索中。本文提出了铜矿床领域本体的半自动化构建方法,能够将铜矿床的知识以本体的形式组织起来,从而进一步支撑我国的找矿工作。首先,通过参考相关专著和文献对我国铜矿床进行成因分类,按照行业相关总则和规范对各类型铜矿床进行相关描述,建立起铜矿床领域本体的概念模型。其次,添加各类铜矿床实例,并参考领域专家建议,完善铜矿床领域本体。最后,通过可视化的方式,在Protégé环境中实现了铜矿床领域本体的构建。通过该方法构建的铜矿床领域本体具有知识层次清晰、关系定义明确、实例丰富的特点,应用于地质资料检索中的精准推荐,为铜矿床资源信息的集成和共享打下基础。     

Design of open pit coal mine slopes: An integrated approach

ABSTRACT

Many of the coal deposits of Western Canada exhibit intensely folded and/or faulted strata. Geological evaluation of such deposits is often difficult and uncertain, and interpretations are subject to significant modifications throughout the exploration, development and mining phases. Design and excavation of open pit slopes under such conditions can present a variety of operational and slope stability problems. Slope design approaches and excavation procedures which are flexible and capable of adapting to changing conditions are essential for rational slope development

This paper examines the problems associated with open pit coal mine slope design in complex geologic environments. A systematic approach to slope design which incorporates engineering geology assessments, slope stability analyses, economic evaluations and mining operational constraints is presented:, Slope design concepts which utilize a variety of slope development techniques, Including benching and artificial support are developed. The design process continues throughout the mining phase in an iterative cycle whereby slope designs are prepared and implemented, remedial measures are applied, existing slopes are documented and evaluated, and slope design concepts and subsequent slope designs are updated and modified as necessary.     

Geotechnical and mine planning considerations in structurally thickened coal deposits at Smoky River Coal Limited,Alberta

ABSTRACT

Structurally thickened coal deposits often form attractive surface mining targets. At Smoky River Coal Limited (SRCL), economic occurrences of structurally thickened coal are found in folded and faulted strata due to the mechanisms of hinge zone dilation and imbricate thrusting (duplexes) respectively. The characteristic features of these steeply dipping and complexly structured deposits require that special attention be given to pit wall design and operational practices.

This paper examines the characteristics of structurally thickened coal deposits at SRCL that affect the surface mining process and explains relevant geotechnical parameters and operational considerations that are used to mine these deposits. Three case histories are also examined to illustrate design and monitoring methods that are employed.     

A Classification System for Environmental Pressures Related to Mine Water Discharges

Abstract.   A survey of information on hazardous mine water discharges in the Central and Eastern European EU Accession Countries and a review of existing ranking systems and studies in Europe indicated a need to establish a common and easily understandable ranking system for environmental pressures that could be used to evaluate the existing situation and to assess and compare potential problems on a multinational and catchment basis. A method is proposed, combining two parameters: the flow rate of the discharge and its qualitative character, expressed as the number of times any environmental standard (maximum permissable concentration, MPC) is exceeded. These two parameters can be combined into one pressure factor (PF), defined as the log of the number of times a standard was exceeded + the log of the emission flow rate, m³/day. The data can be expressed on a special plot, with five gradations that define the number of times the standards were exceeded (from A = more than 1000 times to E = not exceeded), and a numerical designation that reflects the flow rate. The available information and estimated parameters for different mine sites in Central and Eastern Europe were compared on a single plot that shows the number of times the MPC was exceeded and the flow rates generated by mining of different commodities on various scales.     

Stochastic optimisation of long-term block cave scheduling with hang-up and grade uncertainty

Abstract

Mass mining methods provide alternatives in developing deeper and lower-grade mineral deposits. Consequently, block cave mining has been increasingly popular mass mining method, especially for large copper deposits currently being mined by open pit methods. This study adopts similar concepts as in stochastic open pit production planning to the planning of block cave mines, to evaluate their effectiveness in a different approach to mass mining. The main contribution of this study is the incorporation of the uncertainty of delays from hang-ups and grades directly into the production scheduling process of a cave mining operation. Hang-up uncertainty relates to the uncertainty linked to the occurrence of ore that clogs the production draw points. This clogging causes time delays in the production cycle leading to tonnage losses and additional costs. Grade uncertainty is incorporated by means of stochastic orebody simulations. Both uncertainty sources are directly linked to the extraction decisions and influence the optimized schedules. The proposed stochastic integer programming model is applied to the optimization of the long-term schedule of a large-scale, low-grade copper deposit by taking into account hang-up delays in block caving. The results of the optimization maximizing net present value clearly show the capability of the formulation to mitigate the effects of both grade and hang-up uncertainty.     

变质岩区古隆起构造对金矿的控制意义

本文介绍了我省两个不同地质构造单元金矿产出的共同特征,从中总结出某些变质岩区,金矿受控于封闭式古隆起构造的成矿规律:阐述了隆起区内金的成矿系列;以及矿床产出的基本条件和找矿标志,探索了矿床成因。     

基于深度残差网络的有色金属破碎料视觉识别方法

为从报废机械中回收和分选有色金属,提出一种基于深度残差网络的有色金属破碎料视觉识别方法,使分选过程自动化。为从彩色CCD相机采集的图像中获得金属破碎料的感兴趣区域(ROI),通过反距离加权插值算法优化大津方法,使得图像分割的阈值可以自适应调节,以取得更好的分割效果。有色金属破碎料的感兴趣区域作为一个39层的深度残差网络的输入用以训练网络,深度残差网络输出每个有色金属破碎料的类别,工控机通过这种算法和相机标定获取破碎料在传送带上的位置和类别信息来控制分选机构。作为对比,开展了基于传统的卷积网络,如AlexNet、VGGNet16、VGGNet39、GoogLeNet(Inception V2)的有色金属破碎料识别测试。结果表明,基于深度残差网络的方法对铝料、铜料和其他杂料的识别准确率分别达到98.7%、98.9%、96.2%,优于基于传统的卷积网络。     

Environmental Risks Associated with Beneficial End Uses of Mine Lakes in Southwestern Australia

Abstract  Lakes develop when pits from open cut mines are left to fill with groundwater. In recent years, mining companies, mining communities, and regulatory agencies have begun to consider potential beneficial end uses for mine lakes. Beneficial end uses are unlikely to be without environmental impacts, however, and a proper consideration of the total benefit to the community should consider them. This paper briefly reviews potential beneficial end uses and possible environmental impacts that might arise with them for mine lakes in the Collie Basin, a coal mining region in Western Australia. We identified eight distinct, but not necessarily incompatible, end uses from a search of the literature on mine lakes throughout the world: recreation and tourism, wildlife conservation, aquaculture, irrigation, livestock water, potable water, industrial water, and chemical extraction. Recreation, conservation, and possibly aquaculture use the mine lake directly, whereas the other end uses utilise extracted water. All end uses have the potential to have environmental effects, with the most common being an actual or perceived impact on human health and safety. A semi-quantitative risk assessment, using published literature sources, identified wildlife conservation as the end use with the least environmental risk, and irrigation as the end use with the greatest environmental risk. Such risks need to be balanced against economic and social benefits. There is an urgent need for a regulatory framework to address mine lake options.     

矿山生态工业园原理及其应用

介绍了矿山应用生态群落工业园的意义及其设计原理与方法，并结合鑫汇金矿实际情况，依照生态工业园生物食物链的原理，对矿山产出的废料进行了总体的设计，把粗尾砂用于采场胶结充填，细尾砂用于采场非胶结充填；将掘进废石筛分破碎，粗粒级用于建筑，细粒级用于铺路；采用浮选的方法，从炼金剩下的浸渣中提取铅、锌精矿，剩余的尾渣则转化为有用的硫铁矿产品。经过3年多的试验和实践，系统地消化和利用了矿山生产排出的废物，实现了矿山无废开采，并且年产铅、锌精矿4100t、硫铁矿1．65万t、碎石3．5万m^3，取得了显著的经济效益和社会效益。