Schedule-based pushback design within the stochastic optimisation framework

The traditional mine planning framework employs a flawed approach in the design of ultimate pit limits and phases. Conventional methods arbitrarily confine the mine’s extraction schedule during the initial stages, detracting from its optimality before it is created. This work aims to provide a method by which a mine’s phase design is created from an optimal extraction schedule. The schedule-based approach to phase design yields implementable mining phases that mimic the initial raw optimal schedule from which it is based. An attempt to minimise the trade-off between mineability and value is inherent to the approach.     

Oil sands mine planning and waste management using mixed integer goal programming

Strategic mine planning and waste management are an important aspect of surface mining operations. Recent environmental and regulatory requirements make waste management an integral part of mine planning in the oil sands industry. The research problem here is determining the order of extraction of ore, dyke material and waste to be removed from a predefined ultimate pit limit over the mine life that maximises the net present value of the operation. We have developed, implemented, and tested a proposed mixed integer goal programming theoretical framework for oil sands open pit production scheduling with multiple material types. The formulation uses binary integer variables to control mining precedence and continuous variables to control mining of ore and dyke material. There are also goal deviational variables and penalty costs and priorities that must be set up by the planner. The optimisation model was implemented in TOMLAB/CPLEX environment. The developed model proved to be able to generate a uniform schedule for ore and dyke material. This is in line with recent regulatory requirements by Alberta Energy Resources and Conservation Board (Directive 074) which requires oil sands mining companies to develop life of mine plans which ties in to their in-pit tailings disposal strategy. It also provides a practical mining sequence that is consistent with mining oil sands deposit. Similarly, tradeoffs between achieving a goal and maximising NPV can be made.     

SURPAC境界优化功能在露天矿山的应用

露天矿山的开采境界设计对矿山的盈利水平和生产能力有十分重要的影响。以辽宁省某露天铁矿采矿设计为例,介绍了SURPAC三维设计软件对露天矿山终了境界进行优化设计的全过程。通过建立地质数据库、表面模型、终了模型和矿体模型,并将其作为新建块体模型的约束条件,通过SURPAC实现矿山设计的立体呈现,并经运算得出露天境界内分水平矿岩量。分析采用SURPAC软件境界优化前后经济指标的变化情况,为矿山企业生产决策工作提供参考,对露天矿山的境界优化设计有一定的借鉴意义。     

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.     

The equipment utilisation versus mining rate trade-off in open pit mining

This paper investigates the potential value adding role that ‘schemes of exploitation’ may have as part of the open pit mine planning process. The deployment of loading equipment within the push-back of an open-pit mine ultimately determines the ‘mining rate’. Traditional mine planning processes seek to adopt schemes of exploitation that maximise the utilisation of the loading equipment as this will typically minimise mining cost. This paper argues that this does not always lead to the creation of value. A case-study demonstrates that alternative schemes of exploitation, with higher mining costs and lower shovel productivity can actually generate greater value. The results show an increase in Net Present Value from US$920M to US$966M when a less productive configuration of four shovels is set instead of a configuration of two shovels. A sensitivity analysis is presented to show the economic and technical conditions that can favour this new proposal.     

灰色聚类决策在露天采矿分期境界优选中的应用

本文阐述了灰色决策理论和灰色聚类决策的基本原理。针对露天采矿分期境界设计中用参数化函数法搜索所得的多个分期境界方案,提出了一种基于灰色定权聚类和白化权函数的灰色聚类决策方法,实现了露天采矿分期境界设计的灰色聚类决策,得出了分期开采的最优境界方案和可行境界方案。应用证明,该方法在露天采矿分期境界优选设计中是切实可行的,为确定矿山的合理开采境界提供了一种新的技术手段。     

MULSOPS: Multivariate Optimized Pit Shells Simulator for tactical mine planning

Abstract

Production planning, scheduling and allocation of resources in large-scale surface mining operations present a great challenge to mine planning engineers. Ore and waste extraction plans must be executed to achieve tactical objectives using appropriate tools. Many production planning and scheduling and resource allocation methods are based on trial and error, crisis management or subjective judgements with no detailed economic basis or mathematical rigour. In addition, these methods do not consider the random processes governing critical development and production variables. In this study, the authors develop a multivariate pit shell simulator, MULSOPS, which addresses these problems. Rigorous geometric formulations of the ellipsoidal approximations of the pit shells geometry, their expansions and sequential interactions are modeled to mimic material displacement dynamics in an open pit operation. Stochastic and numerical modeling techniques are used to provide solutions to the time-dependent geometric models in random multivariate states Under different production and economic paradigms, the geometric models are simulated to yield the source and characteristics of appropriate cuts. Combined production from successive exposed cuts provides periodic targets for tactical planning. Variance simulation is also used to provide analysts with sensitive stochastic variables for input data definition and tight production target tolerance. A numerical example is used to illustrate the use of MULSOPS for tactical planning in a typical open pit operation.     

充填散体作用下采动岩移的预测及其应用

弓长岭铁矿东南采区上含铁带应用露天开采,下含铁带应用无底柱分段崩落法开采,因开采规划不合理导致上含铁带、下含铁带平行矿体高差约300 m,严重影响矿山安全生产.为保障该矿露天地下协同安全生产,提出利用上含铁带剥离的废石充填下含铁带塌陷坑.利用FLAC3D软件模拟下含铁带开采过程,并对比分析了有充填散体、无充填散体作用下...     

On the Dynamics of Mining Operations in Open Pit Mines

In this paper, mining dynamics is defined as the relationship between the mining rate and movement of mining operations conducted on the benches of a surface mine. This relationship describes the intensity of the pit development in space, in order to meet ore demand at the mill over time. Meeting the mill ore demand is a key factor in optimizing production scheduling in surface mines. Displacement velocity of mining operations within cutbacks, or independent pit units, is introduced in the context of long-term mine planning. Displacement velocity allows the place and time of transition of the mining operations from one independent pit unit to another to be determined as the condition for meeting the mill ore demand. An application using data from Mt Keith Nickel Operations in Western Australia is used to elaborate on the methods presented.     

矿山机械优化配置模型研究

在已有研究成果的基础上，建立了根据矿山规模优化机械配置的一般数学模型，并以一实际露天矿山为例，研究了该模型的具体表达式和影响因素。实际算例表明该优化配置模型是正确而且有效的，具有分形性，既适用于新建矿山的机械设备选型与配置，又适用于已建矿山的机械设备运行、维修和更新。     

Flexible open-pit mine design under uncertainty

The risk associated with a mining project comes from the uncertainties involved in the industry. Mining companies endeavouring to maximize their return for shareholders make important strategic decisions which take years or even decades to “play out”. However, many mining companies feel comfortable with point estimates of all project parameters but realize that no parameter value is known with certainty. A model that incorporates uncertainties and is able to adapt will help deliver a design with a better riskreturn profile. In this paper, a new methodology is developed in order to have a design that is flexible and able to adapt with change. Following recent research on decision making methods in mine planning, this paper develops a mixed integer programming model that determines the optimal design for simulated stochastic parameters. The paper shows how to incorporate optionality (flexibility) in relation to mine, stockpile, plant and capacity constraint options. Obtained results are promising and are helping decision makers to think in terms of value, risk and frequency of execution.     

基于复利法的露天矿山生产设备优化配置

考虑到资金使用的时间价值,依据复利法的折旧方式以及矿山生产规模与设备生产能力的关系,结合矿山的实际情况,运用整数规划及Matlab软件解决露天矿山在生产规划阶段主体机械的设备型号、数量选择的优化配置问题,进而使矿山取得较好的经营效益,为基建期的矿山企业优化机械设备提供了一种新思路。     

白云鄂博东矿境界外资源的开采方案研究

白云鄂博东矿如果可以合理开发利用境界外资源,将延续矿山的生命周期。本文从技术可行性和经济合理性两方面对东矿境界外资源开采方案进行了分析,研究得到:东矿境界外资源开采采用地下开采是唯一选择。在应用Dimine数字矿山软件建立东矿三维地质模型的基础上,根据露天境界外矿体的形态、资源分布情况以及与露天采场的相对位置,研究了地下开采分区。为实现东矿露天转地下不停产衔接,南部境界外挂帮矿采用露天采场内平硐开拓并率先实施,北东境界外挂帮矿开采随后实施,露天坑底境界外开采最后实施。露天矿境界外挂帮矿体的回采不仅充分回收了国家矿产资源,还为露天矿山可持续发展提供了新的途径。     

老矿井走高产高效之路的探索

鸡西矿业集团东海煤矿是一座老矿井,开采条件复杂。通过推进科技进步,完善生产系统,技术改造,实现了合理集中生产,取得了显著效益。可为同类矿井走"双高"之路提供有益的借鉴。     

Stochastic long-term production scheduling of iron ore deposits: Integrating joint multi-element geological uncertainty

Meeting production targets in terms of ore quantity and quality is critical for a successful mining operation. In-situ grade variability and uncertainty about the spatial distribution of ore and quality parameter cause both deviations from production targets and general financial deficits. A stochastic integer programming formulation (SIP) is developed herein to integrate geological uncertainty described by sets of equally possible scenarios of the unknown orebody. The SIP formulation accounts not only for discounted cashflows and deviations from production targets, discounts geological risk, while accounting for practical mining. Application at an iron ore deposit in Western Australia shows the ability of the approach to control a risk of deviating from production targets over time. Comparison shows that the stochastically generated mine plan exhibits less risk in deviating from quality targets than the traditional mine planning approach based on a single interpolated orebody model.     

Stochastic orebody modelling and stochastic long-term production scheduling at the KéMag iron ore deposit,Quebec, Canada

Abstract

Stochastic optimisation provides a framework that is capable of generating a strategic life-of-mine production schedule that increases net present value while simultaneously reducing the risk associated with geological uncertainty. This paper focuses on the application of the stochastic strategic mine planning for technical risk management in the KéMag iron ore deposit in Quebec, Canada, demonstrating the key steps of the framework. The approach first quantifies both the volumetric and multi-element grade uncertainty of the deposit by generating a set of equally probable scenarios of the orebody. In this case study, the boundaries of the lithologies (volumetric uncertainty) defining the KéMag iron ore deposit are generated using a pattern-based wavelet simulation algorithm. The pertinent grade properties, namely, head iron, Davis Tube weight recovery, Davis Tube concentrate iron and silica content (multi-element grade uncertainty) are jointly simulated using the direct block minimum/maximum autocorrelation factors algorithm. Subsequently, the simulated scenarios of the iron deposit serve as an input to a life-of-mine stochastic integer programming production-scheduling model. The latter stochastic optimisation model is employed to manage and minimize the risk associated with the geological uncertainty of the deposit in terms of meeting production targets while generating a mining sequence of extraction maximising the net present value. The results of the case study quantify the risk associated with the product’s silica content, total iron production and expected discounted annual cash flows.     

某铜矿露天转地下隔离矿柱的确定研究

露天转地下隔离矿柱的确定是露天转地下开采经常面临的重要问题,对于金属矿山地下安全生产极其重要。根据某铜矿的采矿工艺、开采深度以及工程地质条件,采用理论计算和FLAC3D有限差分法数值软件对不同厚度的隔离矿柱进行了模拟分析。结果表明,当隔离矿柱厚度为 20 m时,地下开挖导致的顶板变形较小且趋于平稳。20 m是该矿山隔离矿柱厚度的最优值,能够满足安全生产要求。该分析结果为露天转地下安全高效回采提供了理论依据和技术指导。     

露天煤矿绿色开采技术与评价指标体系研究

确定了我国露天煤矿绿色开采目标,提出实现绿色开采目标技术支撑为陡边坡技术、采场工作帮陡帮开采技术、内排土场陡帮排土技术、外排土场减少占地面积技术、逐孔爆破技术、采场与外排土场帷幕与降尘技术、绿色开采新工艺、闭坑治理技术等。建立了评价露天煤矿绿色度的三级评价指标体系,一级指标4个、二级指标12个、三级指标73个。引入"绿色因子"作为各级评价指标值,三级评价指标采用模糊隶属度函数确定其"绿色因子"值。采用模糊综合评价法逐层进行评价二级、一级指标的"绿色因子"值的计算,建立了各级指标绿色因子值数学模型。提出露天煤矿绿色开采评价标准,将露天煤矿"绿色度"划分为5个等级。以黑岱沟露天煤矿为例进行应用实例研究,得出该矿绿色度指标为0.639,属于II级达到良好标准。     

多金属露天矿多目标生产计划优化问题建模及求解算法

针对多金属露天矿山生产计划优化问题难以建模、求解复杂等问题,从多种金属元素、采掘运输成本以及矿石品位三个角度出发,综合考虑矿石产量、品位波动、矿石资源利用率、开采和处理能力以及回采率等多种影响因素,构建了一个多金属露天矿多目标生产计划模型。受粒子群算法启发,提出一种改进狼群算法(IGWO)对模型进行求解,并引入反向学习策略和非线性收敛策略来提高算法的求解效率。以国内某露天矿的实际生产为例,分别利用粒子群算法(PSO)、灰狼算法(GWO)和IGWO算法对模型进行求解对比。结果表明:该生产计划模型更加符合露天矿多种矿产资源综合开采利用的实际需求,IGWO算法较PSO算法运行速度上提高了71%,在求解精度上提高16%。该生产计划方案对多金属露天矿山矿产资源综合利用及精细化排产具有重要的指导意义,可促进企业可持续发展。     

兴县矿区斜沟煤矿浅埋深坚硬厚煤层开采方法研究

根据兴县矿区8#煤层赋存条件、生产条件以及矿井产量要求,通过煤岩体物理力学试验、相似矿井开采类比、矿压显现数值模拟研究和专家系统采煤方法评价分析,认为8#煤层埋藏浅、煤质较硬,采用大采高综合机械化开采方法是可行的;确定在实际生产过程中,选用支护阻力较大的大采高液压支架,并在实际生产过程中取得了良好的效果,有利于在兴县矿区进行推广应用,具有一定的现实意义。