Principles of Probabilistic Regional Mineral Resource Estimation

Five principal sources of uncertainty in quantitative mineral resource estimation are listed and illustrated by means of a simple example (mosaic model) and a case history study for large copper deposits in the Abitibi area of the Canadian Shield. Abitibi copper potential originally was estimated on the basis of 1968 estimates of production and reserves totalling 3.12 Mt Cu. This prognostication now could be evaluated on the basis of 2008 copper production and reserves totalling 9.50 Mt Cu. An earlier hindsight study performed on the basis of 1977 data (totalling 5.23 Mt Cu) showed seven new discoveries occurring either in the immediate vicinities of known deposits or on broad regional copper anomalies predicted from the 1968 inputs. By 1977, the global geographic distribution pattern of large copper deposits in the Abitibi area had stabilized. During the next 30 years, new copper was essentially found close to existing deposits, much of it deeper down in the Earth's crust. In this paper, uncertainties associated with copper ore tonnage are analyzed by comparison of 2008 data with 1968 data using (a) log-log plots of size versus rank, and (b) lognormal QQ-plots. Straight lines fitted by least squares on these plots show that 1968 slopes provide good estimates of 2008 slopes but 1968 intercepts are much less than 2008 intercepts. In each linear log-weight versus log-rank plot, the slope is related to fractal dimension of a Pareto frequency distribution, and in a lognormal QQ-plot it is determined by logarithmic variance. The difference between 2008 and 1968 intercepts represents the increase in copper ore production and reserves from 1968 to 2008. The Pareto model fits actual copper and massive sulphides increase over the past 40 years better than the lognormal frequency distribution model for 10 km×10 km cells on favorable environments in the Abitibi area.      

利用测井信息评价盐湖相烃源岩

盐湖相烃源岩富含膏、盐质成分,使其测井响应特征发生极大改变,给测井评价烃源岩带来困难。基于实测数据,分析了盐湖相烃源岩中普遍发育的纯泥岩、含膏(盐)泥岩和膏(盐)质泥岩有机碳含量的测井响应模式,发现纯泥岩和含膏(盐)泥岩TOC与AC和LogRt呈正比,与DEN呈反比,膏(盐)质泥岩TOC与DEN呈正比,与LogRt呈反比,并基于此建立了盐湖相烃源岩测井评价方法,即首先利用ΔGR区分岩性,再针对不同岩性建立TOC评价模型,最后根据实测S₁+S₂和TOC建立相关关系,就可以求取烃源岩的TOC和S₁+S₂。利用该方法对东营凹陷沙四下亚段烃源岩性质和展布进行分析,发现预测TOC与实测TOC吻合程度高,具有一定推广价值。     

中国昆明地区岩溶洞穴洞口带苔藓植物研究

为了研究中国西南岩溶洞穴植物区系与生物多样性特征, 作者曾两次对云南昆明地区12个岩溶洞穴进行了野外考察和苔藓植物标本采集工作。其中含昆明市石灰岩洞穴1个, 石林县石灰岩洞穴5个和宜良县白云岩洞穴6个。根据采自12个岩溶洞穴洞口带的164件苔藓植物标本研究, 本文首次报道昆明地区洞穴苔藓植物10科18属25种。昆明地区洞穴中分布较多的苔藓植物科有丛藓科( Po ttiaceae) 5属8种,凤尾藓科( Fi ssidentaceae ) 1属4种,柳叶藓科( Amblystegiaceae ) 3 属3 种和青藓(Brachytheciaceae ) 2属3种。溶洞中较常见的4种苔藓植物种类是萤光苔类植物光苔Cyathodiumcavernarum Kunze ( 见于6个溶洞中) , 小凤尾藓Fissidens bryoides Hedw ( 见于4个溶洞中) , 橙色净口藓Gymnostonum calcareum Nees et Ho rsch (见于3 个溶洞中)和长叶扭口藓Tortella tortuosa( Hedw ) Limp ( 见于3个溶洞中)。野外观察表明,受洞穴弱光环境生态因子的限制, 昆明地区洞穴苔藓植物主要生长于洞穴洞口0～ 26m带范围内; 2种丛集型藓类植物, 橙色净口藓Gymnostonumcalcareum Nees et Horsch, 和钩喙净口藓G.recurvirost re Hedw 参与洞口带钟乳石或石笋钙华沉积。      

Analysis on the deployment of mining research supported by the grant program of Deep Resources Exploration and Mining

The Deep Resources Exploration and Mining(DREAM) grant program, within the framework of The National Key Research and Development Program grants, is a pillar to implement China's science and technology strategy in the area of deep resources exploitation. To tackle the insufficient of theories and technologies for the 1000-meter-deep mining, a section of mining, covering the research of basic theories, general technologies and application demonstration, was arranged in the layout of DREAM under the principle of "whole chain design, integrated implementation". In the aspect of basic research, DREAM mainly focused on the deep rock mechanics and mining theory, such as the in-situ mechanical behavior of deep rock, deep high stress induction and energy regulation theory. For the general and key technologies, DREAM supported the research on the mine construction and hoisting, excavation, rock breaking, mining methods and mining safety according to the characteristics of coal and metal mines. For the demonstration application, taking green, safe and efficient as the starting point, DREAM aimed at the green, safe and high efficiency mining, and the demonstration and leading role projects such as the low-waste and high-efficiency back fill mining. Since 2016, 10 RD projects have been funded, and 122 institutional participants with a total budget of RMB 235 million from the central government and RMB 480 million from enterprises as well as local governments have been involved. It is expected that the mining section of DREAM would contribute to establishing the theory and technology system in the area of deep mining and promoting the ability of deep resource exploitation in China.     

Geology and mineralization of the Tiegelongnan supergiant porphyry-epithermal Cu (Au,Ag) deposit (10 Mt) in western Tibet,China: A review

The Tiegelongnan Cu(Au,Ag)deposit in central Tibet contains more than 10 Mt of copper ranking 29 th in the world.It is characterized by typical porphyry-epithermal alteration and mineralization.In order to improve the understanding of porphyry-epithermal copper deposit in Tibet,new zircon U-Pb age and sulfur isotope data along with published data in the Tiegelongnan are presented to investigate the formation and preservation mechanism.Ore-related intrusive rocks in the Tiegelongnan including Early Cretaceous(about 120 Ma)granodiorite porphyry and diorite porphyry are closely related to the northward subduction of Bangongco-Nujiang ocean.Sulfur mainly comes from deep magma,and ore-forming fluid is affected by both magmatic and meteoric water.The metallogenic setting of Tiegelongnan is consistent with those of Andean porphyry copper deposits in South America.The cover of the Meiriqiecuo Formation volcanic rocks,Lhasa-Qiangtang collision and India-Eurasian collision have significance in the preservation and uplift of the deposit.The formation,preservation and discovery of Tiegelongnan play an important role in exploration of ancient porphyry-epithermal deposits in Tibet.     

Carbon cycle variability in tropical Atlantic across two Early Eocene hyperthermals

Early Eocene hyperthermals are geologically short-lived global warming events and represent fundamental perturbations to the global carbon cycle and the Earth’s ecosystem due to massive additions of isotopically light carbon to the ocean-atmosphere system.They serve as ancient analogs for understanding how the oceanic carbonate system and surface-ocean ecosystem would respond to ongoing and future climate change.Here,we present a continuous carbonate record across the Eocene Thermal Maximum 2(ETM2 or H1,ca.54.1 Ma)and H2(ca.54 Ma)events from an expanded section at Ocean Drilling Program Site 1258 in tropical Atlantic.The abundant calcareous nannofossils and moderate carbonate content throughout the studied interval suggest this record was deposited above the calcite compensation depth(CCD),but below the lysocline and under the influence of terrestrial dilution.An Earth system model cGENIE is used to simulate the carbon cycle dynamics across the ETM2 and H2 to offer insights on the mechanism of the rapid warming and subsequent recovery in climate and ecosystem.The model suggests moderate changes in ocean pH(0.1–0.2 unit)for the two scenarios,biogenic methane from a rechargeable methane capacitor and organic matter oxidation from thawing of the permafrost.These pH changes are consistent with a recent independent pH estimate across the ETM2 using boron isotopes.The carbon emission flux during the ETM2 is at least an order of magnitude smaller than that during the Paleocene–Eocene Thermal Maximum(PETM)(0.015–0.05 Pg C yr^-1vs.0.3–1.7 Pg C yr^-1).The comparable pre-and post-event carbonate contents suggest the lysocline did not over deepen following the ETM2 at this tropical Atlantic site,indicating spatial heterogeneity in the carbonate system due to strong dilution influence from terrestrial weathering and riverine discharge at Site 1258.     

Geochronological and geochemical constraints on the petrogenesis of late Mesoproterozoic mafic and granitic rocks in the southwestern Yangtze Block

Late Mesoproterozoic igneous rocks in the SW Yangtze Block are important for understanding the role of it in reconstruction of the Rodinia supercontinent.In the present study,we report new geochronological,geochemical,and Nd-Hf isotopic data for the Cuoke plagioclase amphibolites and granites in the SW Yangtze Block.Geochronological results show that the plagioclase amphibolites and granites have similar late Mesoproterozoic zircon U-Pb ages of 1168-1162 Ma,constituting a bimodal igneous assemblage.The plagioclase amphibolites have high and variable TiO2 contents(1.15-4.30 wt.%)and Mg#(34-66)values,similar to the tholeiitic series.They are characterized by enrichment in LREEs and LILEs,and have OIB-like affinities with positive Nb and Ta anomalies.The plagioclase amphibolites have positive whole-rockεNd(t)(+3.2 to+4.3)and zirconεHf(t)(+4.3 to+10.7)values,indicating that they were derived from an OIB-like asthenospheric mantle source.The granites belong to the reduced peralkaline A-type series and have negativeεNd(t)value of-6.0 andεHf(t)values of-5.8 to-13.8,indicating a derivation from the partial melting of ancient mafic lower crust.In combination with the~1.05-1.02 Ga bimodal igneous assemblage in the SW Yangtze Block,we propose that the Cuoke 1168-1162 Ma igneous rocks were likely formed in a continental rift basin and argue against the existance of Grenvillian Orogen in the SW Yangtze Block during the late Mesoproterozoic.     

Analysis of prospecting polymetallic metallogenic belts by comprehensive geophysical method

This paper is based on the analysis and research on the silver-lead-zinc polymetallic ore in New Ballyhoo Banner in southern Manzhouli of Inner Mongolia.Because metal mineralization brings rock formations,the geophysical features such as low resistivity,high polarization rate and uneven distribution of magnetization,the comprehensive geophysical methods are adopted including high-precision magnetic measurement,high-power induced polarization,IP field middle gradient and controlled source audio-frequency magnetotellurics.In the survey work of multi-metal ore deposits,from surface sweeping to single point measurement,and from single point to section going deeper layer by layer,the resolution of measurement is continuously improved,and various geophysical methods support and complement each other,so explorers can successfully predict the direction,scale and volume of the metallogenic belts in conjunction with geochemical exploration,geological survey and drilling.It has provided a strong basis for completing the exploration task of predicting the reserve volume of ore bodies.The research conclusions of this exploration case have thus a high reference value in the same type of exploration work.     

利用Grapher绘制彩色渐变剖面平面图

在物探扫面工作中,有大量的剖面数据需要绘制成剖面平面图,要求寻找一个高效快速的制图方法.通过对Grapher 自动化功能的分析和实践,编制程序实现了快速绘制彩色渐变剖面平面图的需求,说明利用自动化脚本能够在获得精美图件的同时,可以极大地提高作图效率.     

冷生风化作用对边坡稳定性影响

The experiment shows that considerable influence on density rock properties are subjected by nival weathering conditions. The main parameter defining the rock suitability for solution various engineering and geological problems is its firmness limit on single axis pressing. The firmness properties of sandstone being in absolutely dry condition for Kabakta suite at the beginning of investigation was 64.7 MPa, for Nerungri suite sandstones it was 48. 7 MPa. The investigations showed how much the nival conditions of cryohypergenesis of rock sandstones in Kabakta and Nerungri suites have destructive influence in comparison with aquale and more over aerale conditions. In the aerale conditions sedimentary rock firmness of Kabakta suite decreased to 23.2 MPa, in aquale conditions to 16.5, and in the nivale conditions to 8.9 MPa. In Nerungri suite sandstones are according to 17.7 MPa, 11.1 MPa, and 6 MPa after 300 freezing and thawing cycles. The common sandstone firmness decrease of Kabakta suite was 25 %,of Nerungri suite it was 23.8%. Marlstone samples after 400 FTC decrease to 62% in the nivale conditions and to 33 % in the aerale conditions. After 3～5 years of exploitation marlstone will destruct due to structural and textural inhomogenesis up to gruss, i.e. it will not meet the requirements of durability.Judging by the results of carried out experiment it should be concluded that by cryogenic weathering the sedimentary rocks (sandstones) and rocks with schistose lithogenic texture (marlstone) are subjected to disintegration. The primary rock samples firmness considerably influences on the disintegration rate.     

水系沉积物成矿元素的丰度在矿产资源量预测中的应用

统计资料表明,湘南地区32个有色金属矿区的矿产储量与其所形成的水系沉积物成矿元素的丰度之间,存在一定的线性关系。当用矿上元素组与矿下元素组的垒加衬度比值对异常丰度进行修正即相乘后,这种线性关系更为明显。这就是区域化探扫面应用丰度模型法的依据。     

张家口北部铅锌银多金属矿床区域剥蚀程度分析

张家口北部是河北省重要的铅锌银多金属矿床富集区.区内多金属矿床成矿作用和控矿因素相似,矿化形成均与燕山期酸性小岩体侵入变质结晶基底有关.区域多金属矿床化探异常具可对比性.化探异常图显示区内多金属矿床与化探异常在地表总体呈现无偏性空间分布特征,化探数据因子分析结果表明成矿元素相关性在水系沉积物中未发生改变.据此可将原生晕中依据不同元素组合识别矿体剥蚀程度的思路运用于1:20万化探数据,以此识别区域多金属矿床剥蚀程度.本文以张家口研究程度较高的蔡家营多金属矿床为例,选用可有效识别矿体剥蚀程度的(Bi+V+Ba)/(B+Sb+U)、(U/Th)元素比值,将区域化探数据用于多金属矿床剥蚀程度分析,结果显示区内多金属矿床均出露于剥蚀强度较高区域,受到不同程度的剥蚀.累加NAP值方法显示兰闫多金属矿床剥蚀程度最高,蔡家营、青羊沟矿床剥蚀程度明显降低.区内多金属矿床多分布于岩石风化程度较高的变质结晶基底出露区域及其周边.火山岩盖层下伏变质岩中多金属矿床多呈隐伏-半隐伏状态分布,应是区内下步多金属矿床找矿方向.     

甘肃省黑河干流细土平原区灌溉水入渗运移的初步研究

西北干旱地带农业区的灌溉水入渗是地下水补给的重要途径。在甘肃省黑河干流细土平原区，利用中子仪和负压计观测了灌溉水入渗时包气带的含水率和土水势的变化，初步分析了灌溉水入渗运移规律，确定了灌溉水入渗补给系数随地下水埋深的变化，为本区进行地下水资源评价奠定了基础。     

北祁连成矿带武威地区岩体特征及成因分析

正1区域岩体特征1.1岩体概述研究区处于北祁连造山带中东端北缘,老虎山一毛毛山区域大断裂北侧。沿该断裂带北侧加里东中晚期岩浆侵入活动较为强烈,发育基性一超基性、中酸性、酸性侵入岩,主要分布于莲花山、毛藏寺、直沟、北大坂、银洞沟、干沙沟一带,形成规模巨大的复式岩基(图1)。     

郑州黄河岸边开采地下水对大堤稳定性影响

通过对郑州市黄河大堤一线土体的沉降，压密固结，饱水砂土的地震液化研究，认为黄河大堤附近浅层地下水开采后所诱发的地面沉降，固结过程，不会对大堤造成危害，而饱水砂土的水位降低，还会减轻或消除地震时液化砂土现象，对大堤的稳定性有利。     

尖晶石中的Si含量及其存在形式

自然岩石及简单和复杂体系中实验合成或经重新平衡的尖晶石化学成分显示，在中－低压条件下，与橄榄石共存的尖晶石可含一定量的Ｓｉ，其含量随温度和压力的升高而增大。用最小二乘法对简单体系中 实验数据的热力学模拟发现，Ｓｉ在铬尖晶石中以硅酸盐尖晶石（Ｍｇ２ＳｉＯ４）形式存在，Ｍｇ２ＳｉＯ４组份在铬尖晶石中的活度ａＳＤＭＧ２ＳｉＯ４＝（ＮＳＰＭＧ／２）２＊（ＮＳＰＳｉ）２（ＮＳＰＳｉ代表以４个氧为基础的单位尖     

含盐量对滨海盐渍土物理及水理性质的影响

含盐量的增加使滨海盐渍土含水率与含液率间的差值变大,并导致高估土的干密度,低估土的孔隙比和饱和度。物理性质指标换算和颗粒级配分析试验结果表明,从2%的含盐量开始,随含盐量增加,胶粒含量减少,粘粒和粉粒含量增加,但25μm及以上的粒组含量变化不大。2%以内的含盐量对土的稠度指标影响微弱,当含盐量增加到11%时,盐分结晶形成了较多的晶体颗粒,使土的塑性指数明显下降并呈现出区段性。      

考虑沉桩与群桩间相互影响的复合模量计算方法

总结了复合模量计算的研究现状；提出了考虑群桩间相互影响的复合地基模量计算公式，即由于邻桩对桩间土的加固作用而使复合模量比单桩模型的计算值有所增加，公式同时考虑了沉桩对桩间土模量的提高作用，最后通过算例验证了所提出的公式。     

阳离子浓度对泥沙沉速影响实验研究

应用了静态沉降实验方法中的移液管法,初步研究了水中常见阳离子对河流中细颗粒泥沙沉速的影响,这些阳离子包括Na+、Ca2+、Mg2+和Al3+等。实验结果表明,阳离子浓度对泥沙沉速的影响可以分为两个阶段:①随着阳离子浓度的增加泥沙沉速也增大;②当离子浓度大于某值时,离子浓度对泥沙沉速的影响不大。在同样离子浓度条件下,离子价态高者影响较大。同时分析了长江和黄河干流中下游河段的水化学特性;分析结果表明,在一般的河水水质的情况下,有必要考虑水中阳离子(主要是Ca2+、Mg2+)对细颗粒泥沙沉速的影响。     

矿田地质学的概念和构造岩相分类

矿田系指矿床密集分布,成矿作用集中发育,且在时间、空间和构造建造上具有紧密联系的矿化赋存区段（克列特尔,1956;沃尔弗逊,1966;）,相当于V级成矿区划单元（陈毓川等,1989;朱裕生等,1999）。