多金属矿床工业指标的制定-以中国北方某特大型铜钼矿床为例

多金属矿床工业指标特征的研究表明, 不宜采用单一金属矿床工业指标的制定方法, 必须考虑各种有用金属综合回收的总价值, 制定组合工业指标, 并以此进行各种品位指标的计算。以中国北方某特大型铜钼矿床为例, 介绍了其多金属矿床边界品位、块段最低工业品位、矿区最低平均品位、最小可采厚度和夹石剔除厚度等工业指标的制定过程, 并指出随着企业内部条件和外部环境的变化, 工业指标应是一个动态的标准, 可以修定和优化原有的工业指标。应重视和推广应用地质统计学方法计算储量, 依据市场的变化实行储量和工业指标的动态管理。     

水资源系统模糊优化多维动态规划模型与应用

水资源系统模糊优化多维动态规划模型是水资源系统优化研究中的一个重要课题.在陈守煜多阶段多目标系统模糊优化理论与模型的基础上提出了模糊优化多维动态规划模型,并给出具体应用实例.     

某堤防工程中防渗墙对地下水运动规律影响的初步分析

在1998年之后,长江堤防部分堤段采用了垂直防渗墙措施来处理堤身和堤基中存在的渗流隐患问题,但与此同时,也有人担心防渗墙实施后,会影响原有的江水与地下水之间补给排泄关系而带来新的环境问题.本文将以某实施了防渗墙的堤段为例,采用GMS软件中的MODFLOW计算模块模拟分析临江地层中地下水与江水的动态互动关系,并重点讨论了防渗墙实施后对这种关系的影响,分析结果认为,防渗墙实施后一般不会带来新的地下水环境问题.     

Determination of the critical slip surface in slope stability computations

The analysis of the stability of slopes using limiting equilibrium considerations necessitates the determination of the critical slip surface which yields the minimal factor of safety. The numerous methods currently available for slope stability analysis provide a procedure for assigning a factor of safety to a given slip surface, but do not consider the problem of identifying the critical conditions. This paper presents an effective minimization procedure based on dynamic programming by which the minimal factor of safety, and the corresponding surface, are determined simultaneously. This procedure SSDP (Slope Stability by Dynamic Programming), couples the minimization scheme with Spencer's method of slope stability analysis. It may be applied to slopes of any geometry, layering, pore pressure and external load distributions. No arbitrary restrictions are placed on the shape of the slip surfaces, and the analysis satisfies all equilibrium equations. Application of the procedure to slope stability problems reported in the literature shows that for a given slip surface the procedure yields factors of safety which are almost identical to those reported, but in every case a more critical slip surface, with a lower factor of safety, may be found.     

Determination of optimum cutoff grade with considering dilution

In open pit mining, cutoff grade is one of the most important factors in production planning, which is simply defined as a grade that discriminates between ore and waste. It is also a sensitive parameter can have a major impact on the net present value and cash flow of the projects. On the other hand, dilution is one of the most important and sensitive parameters in the mining projects, which is closely related to the cutoff grade. Choosing the optimum cutoff grade is of considerable importance, since it has a significant impact on the mining operations. One of the most popular algorithms for determination of the optimum cutoff grade is the Lane’s algorithm. But in the Lane’s algorithm, mining dilution and its cost is not considered during the cutoff grade optimization. In this paper, effects of dilution on the cutoff grade are studied using Lane’s theory. Dilution and its cost is inserted directly into cutoff grade optimization process. The cutoff grades obtained using suggested method will be more realistic rather than ones by using the original form of the Lane’s formulation. Results of the study showed that with an increase of dilution, average grade decreases and consequently the cutoff grade increases. As a result of dilution, the quantity Q _m increases and the quantities Q _c and Q _r decrease. Therefore, the annual profit and NPV of project is very significantly reduced.     

风化壳离子吸附型稀土矿稀土浸出工业指标的意义

一直以来,风化壳型稀土矿床均以全相品位来圈定矿体,计算全相储量。而矿山实际生产长期以来是用浸出稀土品位及其总量为依据。在用浸出品位作为基本分析项目时,其分析成本仅有原全相分析的四分之一,且分析周期、普查周期亦大大缩短。同时选取合适的组合样求取浸出率可以求出全相储量,为国家提供稀土总量数据。总之,浸出工业指标比全相分析指标更能反映采选工艺的进步,保证充分利用资源,又能提供二种合理的储量。缩短资源评价周期。节约资源评价费用,是一种经济适用的工业指标,具有一定的参考价值。     

Conditional estimation variances: An empirical approach

One of the tasks routinely carried out by geostatisticians is the evaluation of global mining reserves corresponding to a given cutoff grade and size of selective mining units. A long with these recovery figures, the geostatistician generally provides an assessment of the global estimation variance, which represents the precision of the overall average grade estimate, when no cutoff is applied. Such a global estimation variance is of limited interest for evaluating mining projects; what is required is the reliability of the estimate of recovered reserves or, in other words, the conditional estimation variance. Unfortunately, classical linear geostatistical methods fail to provide an easy way to estimate this variance. Through the use of simulated deposits (representing various types of regionalization)the present paper reviews and discusses the effects of changes in cutoff grade and selective mining unit size on the conditional estimation variance. It is shown that, when the cutoff grade is applied to a pointsupport (sample-size)distribution, the conditional estimation variance appears to be readily accessible by classical formulas, once the conditional semivariogram is known. However, the evaluation of the conditional estimation variance seems to be less straightforward for the general case when a cutoff is applied to the average grade distribution of selective mining units. Empirical approximation formulas for the conditional estimation variance are tentatively proposed, and their performance in the case of the simulated deposits is shown. The limitations of these approximations are discussed, and possible ways of formalizing the problem suggested.     

考虑矿层渗透系数非均质性和不确定性的砂岩型铀矿地浸采铀过程随机模拟与分析

砂岩型铀矿矿层渗透系数普遍具有空间非均匀性,但受试验和分析手段制约,非均匀渗透系数难以准确刻画,导致地浸采铀过程预测出现偏差,限制了地浸采铀过程精细化管控。针对该问题提出一种矿层非均匀参数分布随机表征方法,在此基础上,开展水盐耦合数值随机模拟,揭示不同渗透系数空间分布条件下,群井抽注所引起的溶浸剂储层内部迁移过程和影响范围。在内蒙古某铀矿床应用结果显示：沿区域地下水流方向渗透系数增加,有利于注入溶浸剂疏散;相反,溶浸剂易出现聚集效应。利用水位监测数据对模型边界条件进行识别与验证后,在均质假设条件下溶浸剂扩散速率为210 m2/d,20 a开采周期波及范围为1.53 km2;考虑矿层非均质性和参数不确定性,预测溶浸剂扩散速率为191～228 m2/d,波及范围为1.47～1.74 km2。相比于均质假设,溶浸剂扩散速率和波及范围不确定性显著,分别为17.62%和17.65%。考虑渗透系数非均质性和不确定性,使得溶浸剂迁移转化行为预测结果更具代表性,可为合理制定地浸采铀方案提供更加可靠的依据。     

Optimal lower bound of passive earth pressure using finite elements and non-linear programming

The present study pertains to the finding of the lower bound solution, formulating it as a non-linear programming problem using the generalized method developed by Lysmer with certain variations to incorporate the non-linear no-yield condition constraints directly in the analysis. The method considers the family of plane stress fields having the property that all stresses vary linearly within each triangular element of some mesh which covers the soil mass under study. For this type of stress field it is possible to express all equilibrium conditions as a set of linear constraints and the no-yield as a set of non-linear constraints. The boundary condition constraints may be of linear equality or inequality type. By expressing some of the design variables in terms of the remaining variables the linear equality constraints are implicity satisfied. Such a technique minimizes the complexity of the problem by eliminating the equality constraints and reduces the dimensionality of the problem, saving much, computational effort. The optimal lower bound is isolated by formulating it as a non-linear programming (NLP) problem subjected to both linear and non-linear inequality constraints. The sequential unconstrained minimization technique using the extended penalty function method as suggested by Kavlie has been used to isolate the optimal lower bound. The method has successfully been applied to the passive earth pressure and bearing capacity problem. Numerical results are obtained and compared with Lysmer's solution to show the effectiveness of the present approach.     

Numerical limit analysis of three-dimensional slope stability problems in catchment areas

Risk analysis of existing slopes in catchment areas requires quantification of their stability. This quantification becomes particularly difficult when dealing with larger areas under 3D conditions and including saturated and unsaturated water flow. This paper proposes the use of an effective numerical procedure to solve three-dimensional slope stability problems in large areas subjected to pore pressure effects. This numerical approach, numerical limit analysis, utilizes the finite element method and mathematical programming techniques. Mathematical programming is needed because the basic plasticity theorems for limit analysis can be cast as optimization problems. The generated optimization problem is formulated under a second-order cone programming framework, which is known to solve large-scale problems with great computational efficiency. The main objective of this work was to determine the slope safety factor and the collapse mechanism of soils governed by the Drucker–Prager yield criterion for large-scale 3D problems including pore pressure effects. This approach is applied to an experimental catchment in the Oregon Coast Range that failed after an intense rainfall. The results were compared with a previous stability analysis of the area available in the literature that used a novel 3D limit equilibrium method.     

目标规划方法在地下水资源管理中的应用

以满意决策理论为基础，针对地下水分布多数系统资源管理中关于建模和决策方面的某些突出问题，分析了用目标规划方法解决这些问题的基本思路，并结合某市水资源管理实例，讨论了目标规划方法的建模过程、求解方法、决策过程及其意义。     

防治土壤盐碱化最优灌排模型

将作物临界土壤含盐量和地下水临界埋深等概念应用于防治灌区土壤盐碱化最优规划,提出了非线性规划最优灌排模型.以新疆巩留县团结灌区灌排工程为实例,求解了不同年型(P=20%、50%、75%、95%)的防治土壤盐碱化灌排优化决策,求得的灌排水量、淋洗水量、作物生长季节土壤盐分动态变化及地下水位年内调控过程等结果,与灌区实际情况拟合较好.     

结构可控的地质解释——侵入岩专题地质填图构想

火成岩及其组合的性质不仅受岩浆系统本身性质的约束,也受到成岩环境的控制。因此,火成岩分布区的地质填图应当立足于结构可控的地质解释。基于这种认识,建议侵入岩专题填图按照岩浆系统的几何尺度及其与动力系统的关系划分填图单位。一级岩浆系统受控于全球动力学系统,具有最大的几何尺度;二级岩浆系统与区域地质历史有关,是全球动力系统与岩石圈系统相互作用的产物;三级岩浆系统受控于局部动力系统,与全球动力系统没有直接联系;四级岩浆系统受控于岩浆动力系统与围岩动力系统的相互作用,通常与岩浆产量和通道条件紧密联系在一起;五级岩浆系统受控于具体的岩浆过程,通常是侵入岩区的最小填图单位。但是,岩浆系统具有可无限细分的特点,填图过程中可根据具体情况进一步划分更次级的岩浆系统。对于几何尺度小于地质图表述能力的岩浆系统,建议制作局部放大的专题地质图件,以展示特定岩浆系统的地质特征。     

安徽沿江锰矿开发利用的一种新途径

用黄铁矿作还原剂 (燃料 )与低品位高锰矿混合 ,在立窑中焙烧 ,经水和溶液浸出、净化、合成、过滤等工序生产人造碳酸锰等矿产品。用软锰矿浆吸收废气中二氧化硫     

(NH_4)_2SO_4浸取EDTA-Zn测定试样中RE_2O_3

稀土元素的分析主要采用有机试剂萃取。偶氮试剂做为显色剂的比色分析,分析手续繁琐,也不易得到满意的分析结果,本文在EDTA容量法的基础上,采用较为简便的(NH4)2SO4浸取EDTA-Zn滴定法直接测定新型稀土总量,大大简化了试样的分析过程和操作手续。     

Analytical hydrologic models and the design of policy instruments for groundwater-quality management

This paper explores how analytical hydrologic models can inform the effective design and choice of policy instruments to manage groundwater quality by coupling a social-planner’s problem of optimal groundwater-quality management with analytical solutions from the hydrology literature. A theoretical analysis is performed in order to characterize the properties of an optimal emissions policy. The model is then applied in a numerical analysis of groundwater contamination by chloride from highway deicers, demonstrating the relevance of the theoretical results to practical management settings. This analytical approach can help determine which policy instruments are likely to be effective in controlling groundwater pollution, especially if costly numerical groundwater models are not available for the aquifer in question. Unlike previous economic studies of groundwater contamination, this approach defines optimal emissions policies as a function of geophysical parameters employed by hydrologists such as distance between source and sink, groundwater velocity, and aquifer dispersivity. The theoretical section of this paper also demonstrates that the relationship between geophysical parameters and optimal emissions levels may be ambiguous.     

高塌落度防渗墙填料扩散系数快速测定的透析试验

扩散是低渗透系数情况下溶质迁移的主要方式,目前尚没有测定高塌落度防渗墙填料扩散系数的试验方法。根据沥出试验原理,将处于流动状态的填料用半透膜包裹进行透析试验,通过有限圆柱中溶质迁移解析解对溶质迁移过程进行拟合求其扩散系数,探讨了试验和数据处理的相关问题,研究了膨润土含量和盐浴浓度对扩散系数的影响规律。结果表明,随拟合天数增加,填料中NaCl有效扩散系数减小,而误差增大;高塌落度填料中溶质迁移明显比压实土样中快,按拟合误差小于0.5%作为试验数据取舍依据,这一误差要求实际上是对溶质迁移以扩散为主导这一条件的量化,保证了采用纯扩散解析解进行数据拟合的合理性;扩散系数随填料中膨润土含量增加而减小,随盐浴浓度增加而减小,但在试验范围内数值变化不大,透析试验是快速测定防渗墙填料中溶质有效扩散系数的可行方法。     

长江中游曲流河段河道的近代演化过程研究

曲流河是冲积平原河流中的重要河型之一,曲流河的河道演变对冲积平原的建设与演化起着非常重要的作用。地处江汉平原的长江中游藕池口至城陵矶段河道是最典型的曲流河段,其曲流河道的几何形态和变化过程较为复杂,对该段河道演化过程的研究在河流的开发利用及水利工程建设中具有很好的理论指导意义。本研究通过对历史资料和多期卫星遥感影像的解译与分析,表明长江中游藕池口至城陵矶河段的曲流河道演化在受自然和人类活动双重影响的情况下,该河段河道的演化仍然维持曲流河特征。受大洪水的切滩作用及松滋口、太平口和藕池口3个分流口对洞庭湖的分水分沙的影响,该段河道的演化过程较为复杂。自然裁弯取直和人工裁弯取直在一定程度上改变着河道演化的进程,但由裁弯取直及上游水利工程引起的纵坡降增加产生的冲淤变化将会维持河道的稳定,同时在该河段实施的护岸工程也会抑制河流的横向侵蚀,曲流河段河道演化进入自调整和自组织过程。     

鹿井碎裂蚀变花岗岩型铀矿床溶浸评价研究

本文从矿床的地质评价入手，对矿体形态、产状、规模，矿石的物质成分，矿石结构构造，铀的存在形式，矿床水文地质、工程地质等诸多方面进行了矿床溶浸天然地质条件研究；通过对低品位、大块度的铀矿石进行柱浸工艺试验，获得了一系列溶浸工艺参数；归纳分析出高昔、牛尾岭矿床的矿石灰第2类有利溶浸类型；提出常规采治法、原地破碎浸出和堆浸相结合的采治方案。