Optimization of the catch bench design using a genetic algorithm

Rockfalls are one of the hazards that may be associated with open pit mining. The majority of rockfalls occur due to the existing conditions of slopes, such as back break, fractures and joints. Constructing a berm on the catch bench is a popular method for the mitigation of rockfall hazards in open pit mining.The width of the catch bench and the height of the berm play a major role in the open pit bench design.However, there is no systematic method currently available to optimize the size of these parameters. This study proposes a novel methodology which calculates the optimum catch bench width by integrating the rockfall simulation model and genetic algorithm into a Simulation-Optimization Model. The proposed methodology is useful when used to determine the minimum catch bench width, or the maximum overall slope angle, insuring that a sufficient factor of safety of the slope is included while maximizing the overall profitability of the open pit mine.     

电感耦合等离子体原子发射光谱法测定土壤中8种组分

为满足土地质量调查的需求,实现土壤中多组分的同时消解及准确测定,提高大批量样品的分析效率,建立了土壤样品经高压密闭消解后,采用电感耦合等离子体原子发射光谱法(ICP-AES)测定K₂O、Na₂O、CaO、MgO、Ba、Mn、Cu、Zn的方法。通过对消解体系、酸用量、消解温度等方面的考察,确定最佳实验条件;并对待测液中共存元素Al、Fe的干扰进行探讨,两者均不干扰测定。各组分校准曲线线性相关系数均大于0.999;检出限为0.01~10μg/g。实验方法用于测定土壤标准样品GBW07385、GBW07386、GBW07388中K₂O、Na₂O、CaO、MgO、Ba、Mn、Cu、Zn,测定结果的相对标准偏差(RSD,n=12)为1.1%~4.3%,相对误差RE为-4.0%~4.6%。采用实验方法对土壤实际样品中K₂O、Na₂O、CaO、MgO、Ba、Mn、Cu、Zn进行测定,结果的RSD(n=6)为1.2%~4.6%;并与地矿行业标准方法DZ/T 0279.2—2016测定结果进行比对,测得结果基本一致。     

Anisotropic electrical and abrasion-sensing properties of cement-based composites containing aligned nickel powder

The electrical properties of aligned nickel powder-filled cement-based composites and the abrasion-sensing properties of these composites, as evaluated based on the change in their resistance at varying abrasion depths, were investigated in this paper. Micrograph characterization of nickel powder distribution indicates that the electrical conduction path preferentially forms along the direction of the nickel powder alignment, which leads to increasingly anisotropic electrical properties under greater magnetic field strengths. The level of anisotropy was also determined to be strongly dependent on the nickel powder content. The maximum anisotropic electrical properties were achieved at the percolation threshold content of the nickel powder, which is the critical point for the formation of an effective conductive network. Based on the cement-based composites anisotropic electrical properties and a sectionalized electrode design, the composites filled with aligned nickel powder demonstrated good abrasion-sensing properties, with humidity and temperature self-compensation abilities.     

Development of slope mass rating system using K-means and fuzzy c-means clustering algorithms

Classification systems such as Slope Mass Rating(SMR) are currently being used to undertake slope stability analysis. In SMR classification system, data is allocated to certain classes based on linguistic and experience-based criteria. In order to eliminate linguistic criteria resulted from experience-based judgments and account for uncertainties in determining class boundaries developed by SMR system,the system classification results were corrected using two clustering algorithms, namely K-means and fuzzy c-means(FCM), for the ratings obtained via continuous and discrete functions. By applying clustering algorithms in SMR classification system, no in-advance experience-based judgment was made on the number of extracted classes in this system, and it was only after all steps of the clustering algorithms were accomplished that new classification scheme was proposed for SMR system under different failure modes based on the ratings obtained via continuous and discrete functions. The results of this study showed that, engineers can achieve more reliable and objective evaluations over slope stability by using SMR system based on the ratings calculated via continuous and discrete functions.     

辉钼矿工艺矿物学特征与选矿指标关系研究

在选矿试验研究的基础上,结合对蚀变岩、花岗岩及石英脉等类型辉钼矿的工艺矿物学特征考察,分析了矿石类型、嵌布特征和矿粒粒度等与其选矿指标的关系。研究表明,辉钼矿的选矿指标与其矿粒粒度关系密切,随着辉钼矿矿粒面积累计含量的增加,其选矿指标提高明显。本研究的开展,将为全面开展典型矿产资源工艺矿物学特征调查,运用现代测试分析技术(如MLA等),快速分析矿物嵌布粒度、分布状态等矿石特征,研究总结其与选矿工艺指标关系,建立矿产资源节约与综合利用评价指标体系,实现矿产资源合理开发利用评价,为促进矿产资源节约与综合利用管理奠定基础。     

电感耦合等离子体原子发射光谱法测定土壤中8种组分

为满足土地质量调查的需求,实现土壤中多组分的同时消解及准确测定,提高大批量样品的分析效率,建立了土壤样品经高压密闭消解后,采用电感耦合等离子体原子发射光谱法(ICP-AES)测定K₂O、Na₂O、CaO、MgO、Ba、Mn、Cu、Zn的方法。通过对消解体系、酸用量、消解温度等方面的考察,确定最佳实验条件;并对待测液中共存元素Al、Fe的干扰进行探讨,两者均不干扰测定。各组分校准曲线线性相关系数均大于0.999;检出限为0.01~10μg/g。实验方法用于测定土壤标准样品GBW07385、GBW07386、GBW07388中K₂O、Na₂O、CaO、MgO、Ba、Mn、Cu、Zn,测定结果的相对标准偏差(RSD,n=12)为1.1%~4.3%,相对误差RE为-4.0%~4.6%。采用实验方法对土壤实际样品中K₂O、Na₂O、CaO、MgO、Ba、Mn、Cu、Zn进行测定,结果的RSD(n=6)为1.2%~4.6%;并与地矿行业标准方法DZ/T 0279.2—2016测定结果进行比对,测得结果基本一致。     

Estimation of regional stress by FEM for a heterogeneous rock mass with a large fault

Defining regional stress for a heterogeneous rock mass composed of different rock bodies and a large fault as a displacement boundary condition that is consistent with the mean trend of the in situ stress, we propose a method for determining regional stress from limited stress data by using a 3D finite element method (FEM). First, this method was applied to a small-scale heterogeneous model with a large planar fault that penetrates the region, to clarify the estimation accuracy and the effects of poor modeling and incomplete stress data. The results showed that (1) the method proposed in this study can accurately estimate the stress distribution in the region under consideration except at the bottom when the sliding area of the fault is small, (2) the reproducibility of the given stress can be used to estimate appropriate values of the normal and shear stiffnesses of the fault when the fault is homogeneous, and (3) both incomplete stress data and the assumption that the fault does not slide decrease the accuracy of stress estimation while the given stresses are approximately reproduced. Next, the method was applied to the Tono area, Japan, where a large fault with a complex geometry, called the Tsukiyoshi fault, exists. The results obtained under the assumption that the Tsukiyoshi fault does not slide showed that (1) the stress distribution was estimated reasonably well only for a narrow region that contained the boreholes at which the stress used in the inverse analysis was measured, (2) the stress in the area shows a large scatter and a non-linear trend with depth, which is mainly caused by the Tsukiyoshi fault, and (3) when a fault is heterogeneous, comprehensive examination for the states of the stress and displacements on the fault is needed to obtain a reasonable estimation for the regional stress.     

提高河南某低品位金矿金回收率试验研究

河南某低品位金矿具有嵌布粒度不均匀、粒级分布宽和脉石夹杂严重等特点，金矿物的回收困难。为提高金的回收率，在工艺矿物学的研究基础上进行了一系列的选矿试验研究工作。结果表明：①原矿主 要有用矿物为自然金，原矿金品位为1.39 g/t；银品位为3.35 g/t，可以作为伴生金属综合利用。次要金属矿物主要为黄铁矿，另含有少量的黄铜矿、磁铁矿、辉铋矿和方铅矿等，脉石矿物主要为石英、斜长石、绿 泥石、云母、白云石、方解石，其次含少部分角闪石。②金颗粒主要是以包裹金（占58.83%）形式存在，其次是裂隙金（占23.53%），粒间金占比较小（占17.65%），其中石英包裹金占19.11%。③在最佳的试验条件 下，采用重—浮联合工艺，经3次尼尔森重选、1次摇床精选，重选尾矿经“1粗2精2扫”浮选，最终可以获得重砂含金986.60 g/t、金回收率为50.42%及浮选精矿含金35.75 g/t、金回收率为41.57%。全流程金的总回 收率达到了91.99%，较好地完成了该矿区金矿物的回收。     

电感耦合等离子体原子发射光谱法测定地质样品中铂钯金

在HCl-H₂O₂湿法分解体系中,加入KClO₃分解样品,不仅克服了NO₃^-对铂、钯吸附率的影响,而且极大提高了样品分解能力。样品经HCl-H₂O₂-KClO₃高效湿法分解体系分解后,溶液在10%(V/V)HCl介质中,通过活性炭-717阴离子交换树脂混合吸附剂进行分离富集,有效消除了干扰元素的影响。以Pt 265.945｛127｝ nm、Pd 340.458｛99｝ nm、Au 242.795｛139｝ nm作为分析谱线,建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定地质样品中铂、钯、金的方法。方法中铂、钯、金的检出限分别为0.015、0.012、0.005 1 μg/g,测定下限分别为0.050、0.040和0.017 μg/g。按照实验方法测定地质标准样品中铂、钯、金,测定结果的相对标准偏差(RSD,n=10)均不大于6.7%,测定结果与认定值相符。     

某氰化尾矿中金铜铅铁的综合回收试验研究

云南某矿氰化尾矿中含有金铜铅铁等有价元素。为了充分利用矿产资源,对该氰化尾矿进行了选矿综合回收试验研究。试验结果表明：通过提高磨矿细度和延长浸出时间,氰化尾矿金品位由0.83 g/t可以降至0.35 g/t;采用异戊基黄药和环烷酸皂混合捕收剂选铅,可得到品位和回收率分别为46.83%和35.15%的铅精矿;采用CL-5消除矿浆中游离氰以及铅浮选残留药剂对铜浮选的影响,活化剂AS-2和Na2S活化铜,混合黄药T820、F-1黑药和C5-9羟肟酸作混合捕收剂选铜,可得到品位和回收率分别为17.72%和53.33%的铜精矿;磁选回收铁矿物,先弱磁后强磁,可以得到品位64%和51%两种铁精矿。