Optimizing layout of pumping well in irrigation district for groundwater sustainable use in northwest China

Optimizing layout of pumping well plays a vital role in curbing the groundwater level decline. A novel optimization model is presented in this study. First, the optimal well number is obtained by taking into account factors of local economy and environment based on nonlinear programming model. Then, the well spatial layout assessment model is attained based on information entropy weight and technique for order preference by similarity to ideal solution (TOPSIS). After that, the relative closeness to positive ideal solution of alternative (c_i) on the rationality of well spatial layout in cultivated land is calculated, and a set of alternatives are ranked according to the descending order of c_i. Finally, the well optimization layout is obtained by combining the optimal well number with well spatial layout assessment result based on the GIS data of pumping wells. As a case study, this method was applied in Yongchang Irrigation District of Shiyang River Basin, the arid region of northwest China. Results show that under the conditions of sustainable use of water resources, the irrigation district needed 724 wells for irrigation, with a decrease of 31.0% when compared with the existing number of wells. The wells with low flow rate and operating efficiency distributed in high density where groundwater is over‐exploitation were recommended to be closed. This well optimization layout method is expected to play a significant role in helping make plans for exploiting groundwater at more sustainable level, curbing the groundwater level decline trend, and improving the local ecological environment. Copyright © 2015 John Wiley & Sons, Ltd.     

中国贵金属矿床的基本成矿规律与找矿方向

通过对近年来贵金属矿床勘查进展及其主要类型、主要成矿时代、主要矿集区等的分析与归纳,总结了中国金矿床、银矿床和铂族元素矿床的基本成矿规律,并提出它们各自的找矿方向。中国金矿床类型多,主要形成于中生代和新生代,集中在胶东、辽东、华北地台边缘、小秦岭、阿尔泰、金沙江-红河断裂带、台湾和东南沿海、滇黔桂、陕甘川及长江、黑龙江等主要水系的上游,金矿的找矿方向包括:①老矿区的"探边摸底"和"攻深找盲";②新矿集区的典型研究与采选冶技术改进;③综合利用技术的创新将使相当多的表外矿变为当前可开采的矿床;④新区勘查;⑤加强成矿系列、成矿体系和成矿规律的研究,以理论指导找矿并综合评价。中国银矿以伴生银矿为主,主要形成于中生代和新生代,变质岩、岩浆岩和沉积岩均可容矿,造山带和盆地区的构造破碎带尤其值得重视。当前需要加强对锰矿区含银性和Mn异常区的研究,尤其是中国东部中新生代盆地区断裂带与Mn、Ag化探异常吻合地区,应该综合评价。中国铂族元素矿床可以分为岩浆型、沉积型和热液型三大类,可形成于从前寒武纪到新生代的各个时代,至少构成8个重要成矿远景区(带),重点放在康滇地轴和二叠纪末期峨眉地幔柱影响到的地区,但华北地台老基底中的原生矿及其周边的砂矿不可忽视。     

Chronology of the Tungsten Deposits in Southern Jiangxi Province,and Episodes and Zonation of the Regional W‐Sn Mineralization – Evidence from High‐precision Zircon U‐Pb,Molybdenite Re‐Os and Muscovite Ar‐Ar Ages

Previous studies have obtained some petrogenetic and metallogenic chronological data with SHRIMP (sensitive high-resolution ion microprobe) zircon U-Pb, zircon LA-ICPMS (laser-ablation–inductively coupled plasma mass spectroscopy) U-Pb, molybdenite Re-Os isochron and muscovite Ar-Ar methods in southern Jiangxi Province and its adjacent areas. Based on these, the purpose of this paper is to study the petrogenetic and metallogenic ages and their time gap for different genetic types of W-Sn deposits, and thus to research their numerous episodes, zonal arrangement and their geodynamic background. The result shows that the large-scale W-Sn mineralization in southern Jiangxi Province occurred in the middle to late Jurassic (170–150 Ma), the skarn W-Sn-polymetallic deposits formed much earlier (170–161 Ma), and all of the wolframite – quartz vein type, greisen type, altered granite type and fractured zone type tungsten deposits formed in the late Jurassic (160–150 Ma). In one ore field or ore district, greisen type tungsten deposits formed earlier than quartz vein type ones hosted in the endo- or exo-contact zone; and quartz vein type hosted in the endocontact zone formed earlier than that of exocontact zone. There is no significant time difference between tungsten-tin mineralization and its intimately associated parent granite emplacement (1–6 Ma). They all formed in the same rock-forming and ore-forming system and under the same geodynamic setting. Regionally, rock-forming and ore-forming processes of the W-Sn deposits in the Nanling region (include southern Jiangxi Province, southern Hunan Province, northern Guangdong Province and eastern Guangxi Zhuang Autonomous Region) exhibit numerous episodes. The mineralization in the Nanling region mainly occurred at (240–210) Ma, (170–150) Ma and (130–90) Ma. The tungsten-tin deposits in this region are centered by the largest scale in southern Jiangxi Province and southern Hunan Province, and become small in the east, west, south and north directions. This displays a zonal arrangement and temporal and spatial distribution regularity. Integrated with the latest research results, it is concluded that the W-Sn mineralization in southern Jiangxi Province and its adjacent areas corresponds to the second large-scale mineralization in South China. The Indosinian W-Sn mineralization formed under the extensional tectonic regime between collisional compressional stages, while the Yanshanian large-scale petrogenetic and metallogenic processes occurred in the Jurassic intraplate extensional geodynamic setting of lithosphere extension.     

Seismic response for an isosceles triangle hill subjected to anti-plane shear waves

Acta Geotechnica - This paper presents an exact, analytical solution to the boundary value problem of the anti-plane (SH) waves scattering by an isosceles triangle hill on an elastic half-space by...     

赣南崇义—大余—上犹矿集区不同类型含矿石英中白云母40Ar/39Ar年龄及其地质意义

崇义—大余—上犹矿集区是世界著名的黑钨矿床集中区,本文选择钨锡多金属硫化物石英脉型（柯树岭和漂塘矿床）和锡钨石英脉型（仙鹅塘矿床）3个矿床石英中的白云母开展40Ar/39Ar年代学研究,测得坪年龄分别是：钨锡多金属硫化物石英脉型是 158.9 ± 1.4 Ma（漂塘）、158.8 ± 1.2 Ma（柯树岭）;钨锡石英脉型的是231.4 ± 2.4 Ma（仙鹅塘）,在反等时线图上,其对应的截距年龄分别是158.8 ± 1.6 Ma、158.7 ± 1.9Ma和232.5 ± 2.4 Ma。由此表明,在崇余犹矿集区内存在两个不同成矿时期,即以黑钨矿为主的多金属硫化物石英脉型矿床形成于中侏罗世,集中于160~150Ma之间,与南岭地区钨锡矿床的主成矿期是一致的;而以锡石为主的,并含有大量白钨矿的石英脉型矿床可形成于印支期     

Dynamic stress concentration and scattering of SH-wave by interface elliptic cylindrical cavity

In this paper, the dynamic stress concentration and scattering of SH-waves by bi-naterial structures that possess an interface elliptic cavity are investigated. First, by using the complex function method, the Green‘s function is constructed. This yields the solution of the displacement field for an elastic half space with a semi-elliptic canyon impacted by an anti-plane harmonic line source loading on the horizontal surface. Then, the problem is divided into an upper and lower half space along the horizontal interface, regarded as a harmony model. In order to satisfythe integral continuity condition,the unknown anti-plane forces are applied to the interface. The integral equations with unknown forces can be established through the continuity condition, and after transformation, the algebraic equations are solved numerically. Finally, the distribution of the dynamic stress concentration factor (DSCF) around the elliptic cavity is given and the effect of different parameters on DSCF is discussed.     

华南深部找矿有关问题探讨

华南是我国目前最重要的有色金属矿业基地之一。该地区矿业发达但危机矿山也多,研究程度高但多数矿床的勘查工作在20年前就完成,成矿条件好、已发现矿产地点多面广但进一步找矿难度也大。因此,在华南开展深部找矿势在必行,而且受到了国家、地方政府和企业界的共同关注。中国地质调查局设立了湖南瑶岗仙、康家湾、玛瑙山,江西大吉山、荡坪、岿美山,广西佛子冲、铜坑、栗木、泗顶,广东瑶岭、石人嶂、大宝山等一批危机矿山项目,力争在这些矿山深部实现找矿突破。华南地区开展深部找矿需要研究成矿物质来源、矿床分类、成矿区带划分及其在一定深度（距离地表3000m）的变化情况,需要明确地表的战略性选区与点上的攻深找盲、探边摸底同样重要,需要加快中深钻（1000-3000m深度）钻探及相关测量技术的研究,需要通过对“物质不灭”、“能量守恒”和“时空无限但有序”三原则的把握来评价矿产资源的潜力。     

Scattering of SH waves by a scalene triangular hill with a shallow cavity in half-space

In this study, a theoretical approach is used to investigate the scattering problem of circular holes under a scalene triangle on the surface. The wave displacement function is obtained by solving the Helmholtz equation that meets the zero-stress boundary conditions by adopting the method of separation of variables. Based on the complex function,multi-polar coordinate method, and region-matching technique, algebraic equations are established at auxiliary boundaries and free boundaries conditions...     

应用模糊综合评判原理评价安全煤柱的留设

勘探阶段如何定量评价在厚度较大的新生界下采煤时,如何确定留设安全煤柱的水文工程地质条件,目前尚无完善的方法。以新郑矿区煤田地质勘探获取的水文地质及工程地质资料为例,选取新生界底部含水层、隔水层、风化带、煤层上覆岩组的水文地质及工程地质特征及区域地应力状态五个指标,采用模糊综合评判方法,对矿区留设安全煤柱的水文地质及工程地质条件进行综合评价。评价结果表明:研究区安全煤柱留设条件的优良级得分为48分,中等级得分为33分,较差级得分为19分,表明该矿二1煤层留设安全煤柱的水文地质及工程条件较好。研究结果可为矿区留设安全煤柱提供参考。