湖南大坊金银矿氧化带特征及工业意义   总被引：1，自引：0，他引：1  

王福山 《湖南地质》1991,10(1):17-24

湖南大坊金银矿位于耒阳—临武南北向构造带中段,控矿层位为石炭系中上统壶天群和下统梓门桥组白云岩。矿体受北西和北东向组扭裂面的控制,产于花岗闪长斑岩内外接触带。氧化带的有用组分为金和银,已圈定矿体7个,其平均品位Au 2.68 g/t,Ag26.20g/t。金的粒度以中—细粒为主,氰化浸出率在91％以上,银经槽浸回收率仅20-30%。鉴于金浸出率高,矿体埋藏浅。开采技术条件简单,交通方便等特点,值得开发利用。  相似文献   

Mill-leach-waste cutoff grades for sulphidic copper ore     

W. Schaap 《Geotechnical and Geological Engineering》1984,2(1):51-61

Summary Recent mining literature on cutoff grade theory has come to reflect some viewpoints and analyses expressed earlier in the economic literature. Agreement is best when the cutoff grade policy is established by analysis in stages, starting from the limits of the deposit, and using the maximum net present value objective. In the derivation of the optimal cutoff grade policy a dynamic programming approach is then applied to solve the overall problem as a series of linked, nonlinear, stage optimization problems. A wholly satisfactory use of a dynamic programming methodology requires that two conditions be satisfied: the separability and optimality conditions. The former is, strictly, violated by a heap-leaching or dump-leaching process, the latter by possible forms of resource rent taxation. This paper considers the problem of including such a leaching process in a cutoff grade policy analysis along aforementioned lines. It concludes that a workable method of doing so may be found which, in particular, may be quite satisfactory in arid climates where, in addition, some practical leaching experience already exists.  相似文献   

Uncertainty in Coal Property Valuation in West Virginia: A Case Study     

Michael E. Hohn  Ronald R. McDowell 《Mathematical Geology》2001,33(2):191-216

Interpolated grids of coal bed thickness are being considered for use in a proposed method for taxation of coal in the state of West Virginia (United States). To assess the origin and magnitude of possible inaccuracies in calculated coal tonnage, we used conditional simulation to generate equiprobable realizations of net coal thickness for two coals on a 7 min topographic quadrangle, and a third coal in a second quadrangle. Coals differed in average thickness and proportion of original coal that had been removed by erosion; all three coals crop out in the study area. Coal tonnage was calculated for each realization and for each interpolated grid for actual and artificial property parcels, and differences were summarized as graphs of percent difference between tonnage calculated from the grid and average tonnage from simulations. Coal in individual parcels was considered minable for valuation purposes if average thickness in each parcel exceeded 30 inches. Results of this study show that over 75% of the parcels are classified correctly as minable or unminable based on interpolation grids of coal bed thickness. Although between 80 and 90% of the tonnages differ by less than 20% between interpolated values and simulated values, a nonlinear conditional bias might exist in estimation of coal tonnage from interpolated thickness, such that tonnage is underestimated where coal is thin, and overestimated where coal is thick. The largest percent differences occur for parcels that are small in area, although because of the small quantities of coal in question, bias is small on an absolute scale for these parcels. For a given parcel size, maximum apparent overestimation of coal tonnage occurs in parcels with an average coal bed thickness near the minable cutoff of 30 in. Conditional bias in tonnage for parcels having a coal thickness exceeding the cutoff by 10 in. or more is constant for two of the three coals studied, and increases slightly with average thickness for the third coal.  相似文献   

EUTROPHICATION AND RED TIDES AS CONSEQUENCES OF ECONOMIC DEVELOPMENT   总被引：4，自引：0，他引：4  

Zhao-Yin WANG  Yongsheng WU  and Guangqian WANG Prof.  Dept. of Hydraulic Engineering  Tsinghua University & International Research  Training Center on Erosion  Sedimentation  Beijing  China  Email: zywang@tsinghua.edu.cn or zywang@sun 《国际泥沙研究》2001,16(4)

1 mTRoorcnoxThe EnvirDment AgenCy of UK (l997) defins eUtIDPhication as "the enrichInnt of waters byinorgedc plant nUtrientS that result in the simulation of an mp Of syInPtOInati changes. These includethe inCrased PrOduCtiOn Of aigae or othe aquatic PlantS, affeChng the quallty of the water and distUIbingthe balance Of orpedsms Present within it. Such changes Inay be undesirable and intetw with wateuses." Sndth et al. (l999) indicated tha eopation of waters is mainly caused by h…  相似文献   

90年代中国省级区域经济与环境协调度分析   总被引：131，自引：8，他引：123  

张晓东  池天河 《地理研究》2001,20(4):506-515

在阐述经济环境协调度理论的基础上,建立了环境承载力与经济发展水平之间的协调度模型。并通过对90年代我国省级区域的实证分析,发现我国空间区域经济环境协调度基本符合“U”型曲线,区域经济发展模式大多以牺牲环境为代价,特别是中西部地区的问题比较严重。  相似文献   

汉三角地区经济发展分析与对策     

黄雅静 《热带地理》2007,27(3):259-263

“汉三角”位于湖北、湖南、江西3省交界处的精华地带,属于中部发展中地区,具有区位与交通条件优越、自然资源丰富、旅游资源品种多样、人文气息浓厚等多种优势,是珠三角、长三角地区产业转移的前沿地区。同时伴随着中部崛起战略的提出,在中部地区营造汉三角经济增长极,通过发挥其巨大潜力,不仅将完善我国区域经济空间布局,而且对促进中部崛起具有十分重要的战略意义。文中对汉三角地区经济发展进行了详尽分析,并提出汉三角区域经济发展战略措施。  相似文献   

重大项目对区域经济空间的影响——以广州市钟村镇新火车客站建设为例     

游细斌  魏清泉  苏建忠 《热带地理》2007,27(4):360-363,368

在区域经济发展过程中,重大项目的影响比一般的经济因素显得更为重要和关键。而对受影响的区域来说,在我国现行行政区划体制下,乡镇所受的影响更为直接。2003年,广州新火车客站(以下简称新客站)规划选址于钟村镇石壁地区,引起了国内外的极大关注。通过实证分析,发现新客站的建设将会引起当地经济空间结构的极大改变,同时也会带来一系列的社会问题。  相似文献   

湖南土地资源可持续利用的生态安全评价   总被引：41，自引：0，他引：41  

张建新  邢旭东等 《湖南地质》2002,21(2):119-121

生态安全是土地可持续利用的基础，土地生态安全评价是土地可持续利用研究的前沿课题。以湖南省14个地州市为样本，从1999年社会经济和土地生态环境压力、土地生态环境质量、土地生态环境保护和整治能力等方面的运行数据中选取人口密度、城镇化水平、人均耕地等24个指标，采用均方差客观赋权，从各指标的统计特征值及全国的平均值出发，确定本省的生态安全评价阈值S，计算各地市多指标加权综合评价值，试图对本省土地生态安全进行客观综合评价。  相似文献   

湖南省经济增长的动力机制与潜在问题分析     

邱文彬  陈国生  刘松军 《热带地理》2001,21(2):145-149

通过对湖南在改革开放20年以来所取得的经济增长成果的分析，探讨其经济波动性及其结构矛盾，对开放程度、使用外资额、企业固定资产投资额、工业效率、产业结构、人口规模等多方经济增长的动力机制，采用因子分析法等多种计量手段，分析湖南省经济增长的主要推动因素，揭示湖南省经济增长方式的特点和存在的问题，并提出了相应的对策。  相似文献   

地下贯通工程测量方案的优化理论和方法   总被引：2，自引：0，他引：2  

冯仲科 《测绘学报》1996,25(4):303-308

地下贯通工程的控制测量导线多为加测陀累方位角的导线，本文讨论了贯通工程导线加测陀螺边的个数，位置，以及提高其可靠性，经济性的有关问题。  相似文献