基于光纤系统的物理相似模型温度分布与演化特征

为减小水分因素引起的模型试验相似误差,提出了用温度特征确定模型干燥过程的干燥时间(判断模型试验开挖)的方法。建立了光纤传感测温系统,提出克里金空间插值法的估值公式计算模型温度,给出物理模型的温度变异函数表达式。开展了3.0 m×1.2 m×0.2 m二维模型和3.6 m×2.0 m×2.0 m三维模型温度监测试验,监测时间分别超过65,310 d,绘制出模型温度分布云图,探讨了模型干燥(试验开挖)的判断方法。研究表明,模型干燥存在水化放热和液-气相态转变的不同过程,模型温度场演化具有明显的阶段特征,最大温差分别为3.0,4.8℃。干燥后期呈现出竖直方向上高下低的温度梯度,水平方向大致相同的特征,其中低温核区下移并消失是判断模型干燥完成的标志,可作为试验开挖的判断指标。二维模型干燥时间为47 d左右,三维模型干燥时间为213 d左右。     

基于SURPAC的ANSYS三维复杂模型的构建方法

对大型数值分析软件FLAC^3D、ANSYS进行了对比, 发现ANSYS在对不规则模型进行网格划分方面优于FLAC^3D, 并针对FLAC^3D、ANSYS在建立不规则复杂模型时存在耗时耗力等问题, 提出了基于SURPAC的ANSYS复杂模型的构建方法 采用JAVA语言编写了SURPAC-ANSYS接口程序, 将SURPAC模型的点线面数据转换成ANSYS识别的数据格式, 从而实现SURPAC模型到ANSYS模型的构建。最后, 通过新城金矿V^#矿体的工程实例, 解决了SURPAC模型到ANSYS的转换以及模型难重构等问题。结果表明 此构建方法可行且高效。     

A model for predicting the dispersion of dust from a haul truck

The Industrial Source Complex 3 (ISC3) model, created by the United States Environmental Protection Agency (USEPA), is the best available model for estimating the dispersion of particulate matter less than 10 microns in diameter (PM₁₀) from surface mining operations; its use is required in applications for surface mining permits. However, it has been proven to over-predict actual PM₁₀ dispersion concentrations by a factor of 2?–?5. A newly developed model focuses on estimating PM₁₀ dispersion from haul trucks, since past research has shown that the majority (80?–?96%) of PM₁₀ emissions from surface mining operations are from mobile sources. This model is a promising improvement over the ISC3 model. Modeling exercises using the new model on actual surface mine hauling operations demonstrated a 77% improvement over the ISC3 model.     

露天矿采矿作业计划的二元整数规划数学模型

在同时考虑边界品位优化和开采顺序优化情况下,为了实现最大化净现值,提出了一种新的基于二元整数规划的露天矿作业计划模型。该模型包含3个部分:(1)实际经济损失;(2)概率分布和平均品位;(3)预期经济损失。通过物理约束将一个矿块的经济损失评估与概率集成在一个二元整数规划模型中。该模型基于最佳加工决策来确定每个时期的最优开采顺序。为了验证提出模型的适用性,对某金矿案例进行了研究分析。结果表明:使用提出模型获取到的开采顺序是切实可行的,该模型可以在合理的时间内得到较高的最优净现值。     

Dynamic modelling of copper solvent extraction mixer–settler units

The copper Leaching, Solvent Extraction and Electrowinning circuit (LX–SX–EW) is one of the most effective processes for extracting copper from low grade ores. This work focuses on the liquid–liquid extraction SX sub-process, since many difficult to handle operational problems within LX–SX–EW circuits are related to SX malfunction. Controlling these problems better can reduce operational costs and increase recovery and copper production. Realistic dynamic simulation is a standard tool nowadays to design and assess more effective control strategies. In this work we present a general dynamic model for SX mixer–settlers, and applied it to two different units, one located in an extraction stage and the other in a stripping stage of a copper plant. The model includes a non-trivial settler hydrodynamics represented by a set of nonlinear differential equations for both mixer and settler units. The mixer is modelled as a continuous stirred tank reactor and the settler as a hydrodynamic circuit combining series and parallel connections of continuous stirred tank and plug flow reactors. The model was calibrated with industrial plant data, resulting in realistic simulations of outlet copper concentrations. Using the proposed model, we obtained better fitting than that achieved with simpler settler models that include only a time delay. The model fitting parameters provide sufficient flexibility to accurately reproduce the dynamics of different units in industrial plants.     

Modeling the contribution of specific grinding pressure for the calculation of HPGR product size distribution

Vale, one of the largest mining companies in the world, has prioritized the development of HPGR technology for practical application in its current projects. An existing model for the HPGR, capable of predicting product size distributions, has been evaluated under distinct grinding conditions for one feed material. The effect of grinding pressure and feed size distribution were investigated. The model response showed a clear dependency of product size distribution with specific grinding pressure. As a result, specific grinding pressure was incorporated into the model, allowing for predicting product size distribution at practical values of this important process parameter. Based on this result, a characterization procedure was envisaged so as to produce parameters for the model. The procedure does not require complex experimental procedures, and all of the testing can be carried out in an expedited form in an instrumented bench-scale HPGR, using small samples of about 10 kg. The only analyses required are size distributions. The model was implemented in the Modsim? plant-wide simulator, with facilities to predict product size distribution for any roll diameter, length and speed of an HPGR machine.     

白钨矿与黑钨矿分流分速异步浮选过程中的模拟研究

本文针对矽卡岩型黑白钨混合矿,在相关异步浮选分离研究的基础上,利用回归分析与人工神经网络建立起不同工艺条件与矿物可浮性变化规律关系模型,为解决浮选建模过程中遇到的多变量、非线性、强耦合、大滞后等难题,实现浮选过程的优化控制提供参考。研究结果表明：对矿物浮选累计回收率的影响因素大小依次是Time > pH > 羟肟酸 > 柠檬酸。对于预测矿物不同工艺条件下的浮选指标,回归模型预测精度较差,白钨矿和黑钨矿浮选累计回收率预测值与试验值之间的相关系数R₂分别为0.805、0.827,而神经网络模型具有较好的预测精度,相关系数R₂分别为0.944、0.947。人工混合矿分离结果与单矿物浮选规律有很好的一致性,应用所建立的神经网络模型对于更好的掌握不同矿物之间的浮游规律,优化浮选工艺有一定的意义。     

煤炭智能精准开采工作面地质模型梯级构建及其关键技术

随着国家大力推进工业化与信息化融合,煤炭智能精准开采已经成为行业大趋势,众多煤炭企业和科研院所开展了一系列试验研究和工业示范工程。然而,地质条件的适应性不足已经成为制约煤炭智能精准开采的技术瓶颈,迫切需要构建高精度、透明化的工作面三维地质模型。以黄陵煤矿某智能化工作面为例,分析了智能精准开采对地质透明化的时空需求,一方面要确保工作面前方未采区域一定范围内地质条件的"透明化",另一方面要在采煤机完成一次截割的时间内完成透明化工作面三维地质模型的动态更新。统筹分析工作面地质探测技术现状和智能开采的集控水平,提出了构建透明工作面三维地质模型的总体思路:按照不同的地质、采掘阶段,将回采工作面地质模型分为4个层级,即黑箱模型、灰箱模型、白箱模型和透明模型。在工作面设计阶段,基于地面钻探与采区三维地震资料,可以构建工作面的"黑箱模型",其精度处于"十米级";在工作面掘进阶段,开展三维地震资料地质动态解释,可以构建工作面的"灰箱模型",其精度处于"十米级～米级";在工作面采前阶段,综合利用槽波、坑透等工作面地质勘探技术,可以构建工作面的"白箱模型",其精度能够达到"米级～亚米级";在工作面回采阶段,动态融入回采揭露的地质信息,并进行随采地震动态监测,可以构建起工作面前方50 m的工作面"透明模型",其精度达到"亚米级"。为此,亟需研发一批关键技术与装备,主要包括三维地震资料地质动态解释技术、煤矿井下孔中物探技术与装备、回采工作面随采地震监测技术、工作面监测数据地质信息提取和多源异构地质信息动态融合技术等,逐级构建智能开采工作面的地质模型,渐次实现工作面的三维地质透明化,为煤炭智能精准开采提供地质保障。     

Application of next event matrix modelling technique in surface mining

ABSTRACT

The Next Event Matrix (NEM) approach to model building, a powerful extension of queueing theory, has not received much attention in the mining industry. In this paper, the theoretical tools with which the NEM model can be constructed for use in the analysis of the materials handling problems of small independent mining operations are examined. Specifically, the technique is presented with particular reference to a multichannel stripping operation in parallel. In so doing, the author is convinced that the easy adaptability of the multichannel model to single-channel mining systems will be very attractive to the model user. The strength of this approach is shown through the mathematical and queueing models for equipment movements and performance characteristics and their attendant subroutines.     

Buffering of Acidic Mine Lakes: The Relevance of Surface Exchange and Solid- Bound Sulphate

Abstract.  Buffering mechanisms in an acidic mine lake in Lusatia, Germany were investigated. The titration curve has four sections with different buffering mechanisms: (1) buffering by free hydrogen ions and hydrogen sulphate (pH = 2.55-2.9), (2) buffering by Fe with bound SO₄ (pH = 2.9-4.3), (3) buffering by Al with bound SO₄ (pH = 4.3-5.5), and (4) buffering by surface exchange of SO₄ and basic cations (pH > 5.5). Three different phase models were applied to simulate the titration curve: (1) an iron and aluminium hydroxide model; (2) an iron and aluminium hydroxysulphate model; and (3) an iron hydroxide model with surface exchange for SO₄, Ca, and Mg, coupled with an aluminium hydroxysulphate model. The uncertainty of model input parameters was accounted for in a sensitivity analysis. Only the third model, which considers surface exchange, was able to adequately reproduce the measured titration curve.     

Geological Analysis and Numerical Modeling of Mine Discharges for the Sanshandao Gold Mine: 2. Simulation and Prediction of Mine Discharges

A two-dimensional model is presented as a way to hydrogeologically characterize the controlling factors in the Sanshandao Gold Mine. The finite element method was first applied to simulate the ground water system of the current operation, using leakage data and the calculated recharge. An inverse model was applied to the observed data (e.g., head and discharge) to verify and calibrate the ground water simulation model and to estimate the hydrogeological parameters for the water-bearing zones. Nonlinear mathematic programming was used to solve the inverse model and to estimate the model parameters in 17 districts with different hydrogeological characteristics. The finite element equations were solved by means of a large non-symmetrical sparse equation. The results were in agreement with what is currently observed in the mine. The models and the estimated parameters were then applied to predict the mine water discharge for drifts extending to depths of −330 to −600 m during the next development stage. In order to improve the predicted accuracy of the numerical model, an iterative element mesh was added in the districts near the drainage drifts so that the computed discharges that flowed into the drifts would approach the recharges that flow into the borders of the mine. The model was also used to understand how the mine discharge would be influenced by factors such as unsteady ground water flow and the construction of hydraulic barriers to restrict ground water from entering the pits. Part 1 of this article can be found at doi:.     

Damage in rock under explosive loading: Implementation in DYNA2D of a TCK model

Abstract

The rock fragmentation, that allows its mining, is the main objective pursuited in blasting. The purpose of this paper is to review a material model to which a rock under an explosive detonation may respond. A well-known model, TCK, to compute damage, previous to rock fragmentation, has been analysed. A source code to implement the model has been written, and the logical secuence of necessary operations for the computer coding is described in detail.     

A novel approach to the geometallurgical modelling of the Collahuasi grinding circuit

Compañía Minera Doña Inés de Collahuasi SCM initiated the development of a new geometallurgical model to characterize its Rosario deposit in terms of its comminution circuit capacity and flotation performance. The comminution component of the model is now complete and is described in detail in this article.The model uses a combination of simulation and power-based approaches to relate ore hardness and flotation feed size to grinding circuit throughput. Ore hardness values are provided by Collahuasi’s block model which has been populated with ore characterisation data derived from Bond ball work index tests, JK drop-weight tests and SMC Tests^® on diamond drill cores. The influences of planned and unplanned maintenance downtime are taken into account both in terms of frequency and duration.The accuracy of the model is demonstrated using weekly production data taken from the period January–December 2008, showing an average relative error of 5.2% and an R² value of 0.95.The model is now in successful routine use at the mine for planning purposes and is currently in the process of being further developed to incorporate the response of the flotation circuit.     

CFD modelling of stirred tanks: Numerical considerations

The aim of this paper is to demonstrate that the Multiple Reference Frames (MRF) impeller rotation model and the standard k–ε turbulence model, as commonly used in engineering CFD simulations of stirred tanks, can accurately model turbulent fluid flow provided very fine grids coupled with higher-order discretization schemes are used. The MRF model has been found to give adequate results for the steady-state simulation of stirred tanks but the k–ε turbulence model generally under or over-predicts turbulence. In this study the CFD software Fluent 6 is used to simulate flow in a small baffled tank of standard geometry agitated by a Rushton turbine impeller. Simulations are conducted on four grids of significantly different resolution using the upwind, central and QUICK discretization schemes. CFD model results are evaluated in terms of the predicted flow field, power number, mean velocity components and turbulent kinetic energy using published experimental data. The general flow field and mean fluid velocity predictions are not strongly influenced by either the grid resolution or discretization scheme. However, turbulent kinetic energy predictions are strongly influenced by both the grid resolution and discretization scheme. In this study a grid consisting of nearly 2 million control volumes in one half of a 15 cm diameter stirred tank, combined with a high-order discretization scheme, was required to accurately predict the turbulent kinetic energy. These represent conditions which are considerably more numerically intensive than used in most similar studies and suggests that the poor predictions of turbulence obtained using the k–ε turbulence model, often noted in the literature, may be due to numerical errors rather than inadequacies in the turbulence model.     

Phenomenological mechanical block model of an element of a deformable medium. Part 1: Definition and basic properties

Conclusions The simplest mechanical block model of a medium, whose behavior is determined by Hooke's generalized law of elasticity for small deformations, and by classical laws of plasticity for more significant deformations, is constructed. It is shown that conversion from a mechanical block model of a medium, which has finite block dimensions, to an idealized model consisting of blocks of zero dimensions (a plane with a thickness equal to zero), occurs with retention of the directions of simple shears and simple elongations, or the directions of the slip planes (a slip plane is a plane, along the normal to which simple elongation occurs; two simple shears occur in two mutually orthogonal directions falling in the plane). Symmetry of simple shears does not follow from the symmetry of the strain tensor. The components of the vector {ie306-1} are referenced from states of pure shear. Dynamic manifestations of the model under consideration for a medium will be discussed in the next part of the study. Mining Institute. Siberian Branch of the Russian Academy of Sciences, Novosibirsk. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 26–35, July–August, 1998.     

刚柔耦合大型带式输送机的平衡模型降阶

大型带式输送机是具有超长黏弹性体的机电一体化刚柔耦合系统,而传统的刚性静态模型不能反映出大型带式输送机的特性,需要在建模时考虑其黏弹特性。基于有限元法建立了大型带式输送机的黏弹性动力学模型,但模型阶次较高。为了易于低维控制器的设计以及降低控制"溢出",利用基于平衡实现的截断降阶法、残差降阶法对大型带式输送机进行模型降阶,得到系统的低阶模型。对原始高阶模型和降阶模型分别进行仿真试验,仿真结果验证了降阶前后主要模态保持不变,降阶模型精度能够满足要求。提出的大型带式输送机的降阶模型,表明了动力学建模与模型降阶法的有效性和正确性,为基于智能算法的带式输送机控制器的设计提供了参考。     

用于FLAC 3D力学分析的矿床块段模型优化建模技术研究

FLAC^3D主要是模拟计算地质材料和岩土工程的力学行为,可以对矿山开采中产生的空区及地表移动问题进行数值模拟,并进行稳定性分析。但对于复杂的工程和地质条件,FLAC^3D本身的前处理能力不强,建立的模型不能准确反映实际情况,要做大量简化。因此,探讨依据FLAC^3D网格划分的原则和三维矿床软件SURPAC构建块段模型的方法,对用于力学分析的块段模型构建的步骤、原则等进行研究,使建立的模型得到优化,使其能够直接作为FLAC^3D分析的前处理模型进行模拟计算,并结合弹性力学的原理验证了其正确性,同时用优化后的前处理模型结合云南某铜矿的实际进行力学分析,验证了该方法的可行性和准确性。     

煤粉工业锅炉燃烧的数值模拟

为了更好地把握锅炉的性能,应用Fluent软件对某新型高效煤粉工业锅炉内的燃烧过程进行了三维数值模拟.采用非预混燃烧模型模拟化学反应过程,用P-1辐射模型计算辐射传热,用Realizable κ-ε湍流模型模拟气相运动,对固体颗粒相的求解采用随机轨道模型.模拟所得到的炉内温度场、离散相和连续相轨迹分布合理,温度场和实测值较为吻合.模拟结果表明,通过适当降低锅炉的负荷,能够进一步改善煤粉燃烧温度场分布.     

煤低温氧化过程中元素转化行为的动力学分析

通过把参与氧化反应的复杂的煤有机体,分成C,H,O,S和N元素,并基于氧化过程中这些元素含量的变化,借助于准一级反应模型,Coats and Redfern’s模型和Freeman and Carroll’s模型,对煤低温氧化动力学特性进行研究。研究表明,这些元素转化遵循准一级反应动力学和Coats and Redfern’s模型,并且这两种模型计算得到的活化能比较接近。在煤低温氧化过程中这些元素表现出较低的反应速率,仅为10-5～10-6,这表明中间络合物的生成速率非常缓慢。同时研究证明了不同元素活化能与指前因子之间存在动力学补偿效应。     

Evaluating the Nakajima et al. model for rectangular-aperture screens

Nakajima et al. [Trans. Inst. Mining Metall. 87 (1978) C194] developed a method to measure the shape distribution of particles in terms of their size and thickness. This method was later extended to include models for square, rectangular, and circular aperture screens. In this project, the empirical equation for the probability of particles passing through the rectangular aperture screen in the Nakajima et al. model is replaced with a “basic probability” model and the results are compared. Next, regression equations relating the efficiency parameter of the model to selected screening operating variables are developed. Finally a “modified” Hatch and Mular model is introduced in the Nakajima et al. model and the results are compared with the experimental data. It is shown that both the new models fit the experimental results obtained from rectangular-aperture screens better than the original Nakajima et al. model.