从柴达木盆地油田水和盐湖卤水中分离提取铀的可行性分析

除固体铀矿和海水之外,油田水和盐湖卤水是十分重要的液体铀资源。分析了从柴达木盆地油田水和盐湖卤水中分离提取铀的可行性,预测了铀在油田水和盐湖卤水中的化学形态,提出了适宜的铀分离提取方法(吸附法),探讨了分离提取机理、分离提取过程中可能的干扰因素及相应的排除方法,进而对研究工作提出了一些建议。     

Review of the NURE Assessment of the U.S. Gulf Coast Uranium Province

Historic exploration and development were used to evaluate the reliability of domestic uranium reserves and potential resources estimated by the U.S. Department of Energy national uranium resource evaluation (NURE) program in the U.S. Gulf Coast Uranium Province. NURE estimated 87 million pounds of reserves in the $30/lb U₃O₈ cost category in the Coast Plain uranium resource region, most in the Gulf Coast Uranium Province. Since NURE, 40 million pounds of reserves have been mined, and 38 million pounds are estimated to remain in place as of 2012, accounting for all but 9 million pounds of U₃O₈ in the reserve or production categories in the NURE estimate. Considering the complexities and uncertainties of the analysis, this study indicates that the NURE reserve estimates for the province were accurate. An unconditional potential resource of 1.4 billion pounds of U₃O₈, 600 million pounds of U₃O₈ in the forward cost category of $30/lb U₃O₈ (1980 prices), was estimated in 106 favorable areas by the NURE program in the province. Removing potential resources from the non-productive Houston embayment, and those reserves estimated below historic and current mining depths reduces the unconditional potential resource 33% to about 930 million pounds of U₃O₈, and that in the $30/lb cost category 34% to 399 million pounds of U₃O₈. Based on production records and reserve estimates tabulated for the region, most of the production since 1980 is likely from the reserves identified by NURE. The potential resource predicted by NURE has not been developed, likely due to a variety of factors related to the low uranium prices that have prevailed since 1980.     

Petrochemical and Mineralogical Constraints on the Source and Processes of Uranium Mineralisation in the Granitoids of Zing-Monkin Area,Adamawa Massif,NE Nigeria

Zing-Monkin area, located in the northern part of Adamawa Massif, is underlain by extensive exposures of moderately radioactive granodiorites, anatectic migmatites, equigranular granites, porphyritic granites and highly radioactive fine-grained granites with minor pegmatites. Selected major and trace element petrochemical investigations of the rocks show that a progression from granodiorite through migmatite to granites is characterised by depletion of MgO, CaO, Fe₂O_3, Sr, Ba, and Zr, and enrichment of SiO₂ and Rb. This trend is associated with uranium enrichment and shows a chemical gradation from the more primitive granodiorite to the more evolved granites. Electron microprobe analysis shows that the uranium is content in uranothorite and in accessories, such as monazite, titanite, apatite, epidote and zircon. Based on petrochemical and mineralogical data, the more differentiated granitoids (e.g., fine-grained granite) bordering the Benue Trough are the immediate source of the uranium prospect in Bima Sandstone within the Trough. Uranium was derived from the granitoids by weathering and erosion. Transportation and subsequent interaction with organic matter within the Bima Sandstone led to precipitation of insoluble secondary uranium minerals in the Benue Trough.     

Raw materials activities of the manhattan project on the colorado plateau

The Manhattan Project was a highly secret project during World War II to develop the atomic bomb, and included the acquisition of raw materials. It was carried out by the Army’s Corps of Engineers Manhattan Engineer District. In the United States, 2,698,000 pounds of uranium oxide were acquired at various vanadium mills on the Colorado Plateau, mainly from the treatment of tailings. Geologic investigations conducted by a contractor, Union Mines Development Corporation, laid the ground work for the exploration activities of the Atomic Energy Commission which succeeded the Manhattan Engineer District in 1947     

Unconventional Energy Resources: 2011 Review

This report contains nine unconventional energy resource commodity summaries prepared by committees of the Energy Minerals Division (EMD) of the American Association of Petroleum Geologists. Unconventional energy resources, as used in this report, are those energy resources that do not occur in discrete oil or gas reservoirs held in structural or stratigraphic traps in sedimentary basins. These resources include coal, coalbed methane, gas hydrates, tight gas sands, gas shale and shale oil, geothermal resources, oil sands, oil shale, and uranium resources. Current U.S. and global research and development activities are summarized for each unconventional energy commodity in the topical sections of this report. Coal and uranium are expected to supply a significant portion of the world’s energy mix in coming years. Coalbed methane continues to supply about 9% of the U.S. gas production and exploration is expanding in other countries. Recently, natural gas produced from shale and low-permeability (tight) sandstone has made a significant contribution to the energy supply of the United States and is an increasing target for exploration around the world. In addition, oil from shale and heavy oil from sandstone are a new exploration focus in many areas (including the Green River area of Wyoming and northern Alberta). In recent years, research in the areas of geothermal energy sources and gas hydrates has continued to advance. Reviews of the current research and the stages of development of these unconventional energy resources are described in the various sections of this report.     

PALAEOCLIMATOLOGICAL SURVEY OF STALAGMITES FROM COASTAL AREAS IN TANZANIA

ABSTRACT. The aim of this study was to assess the potential of Tanzanian stalagmites as palaeoclimatic archives. Twelve stalagmites were collected in cave systems in the coastal areas. U-series dating, combined with published ¹⁴C-data, shows that one of the stalagmites was precipitated during the latter half of the latest glacial, between approximately 39 and 27 ka. Stable isotope analysis results indicate millennial-scale fluctuations in atmospheric CO₂ level during that time; and these fluctuations show a pattern very similar to that of the δ¹⁸O variations in the GRIP and Byrd ice-cores. The other stalagmites analysed turned out to be too porous and/or contained too much detritus to allow for reliable U-series dating. Due to low uranium content, the precision of the dating results is generally also poor. Samples from the five most compact and clean specimens yielded ages from c. 105 ka to c. 17 ka, though sometimes with an inverse age stratigraphy, indicating that the stalagmite precipitates were partly not compact enough to prevent post-depositional uranium leakage.     

Net Energy Payback and CO2 Emissions from Three Midwestern Wind Farms: An Update

This paper updates a life-cycle net energy analysis and carbon dioxide emissions analysis of three Midwestern utility-scale wind systems. Both the Energy Payback Ratio (EPR) and CO₂ analysis results provide useful data for policy discussions regarding an efficient and low-carbon energy mix. The EPR is the amount of electrical energy produced for the lifetime of the power plant divided by the total amount of energy required to procure and transport the materials, build, operate, and decommission the power plants. The CO₂ analysis for each power plant was calculated from the life-cycle energy input data. A previous study also analyzed coal and nuclear fission power plants. At the time of that study, two of the three wind systems had less than a full year of generation data to project the life-cycle energy production. This study updates the analysis of three wind systems with an additional four to eight years of operating data. The EPR for the utility-scale wind systems ranges from a low of 11 for a two-turbine system in Wisconsin to 28 for a 143-turbine system in southwestern Minnesota. The EPR is 11 for coal, 25 for fission with gas centrifuge enriched uranium and 7 for gaseous diffusion enriched uranium. The normalized CO₂ emissions, in tonnes of CO₂ per GW_eh, ranges from 14 to 33 for the wind systems, 974 for coal, and 10 and 34 for nuclear fission using gas centrifuge and gaseous diffusion enriched uranium, respectively.     

Statistical sampling of the distribution of uranium deposits using geologic/geographic clusters

The concept of geologic/geographic clusters was developed particularly to study grade and tonnage models for sandstone-type uranium deposits. A cluster is a grouping of mined as well as unmined uranium occurrences within an arbitrary area about 8 km across. A cluster is a statistical sample that will reflect accurately the distribution of uranium in large regions relative to various geologic and geographic features. The example of the Colorado Plateau Uranium Province reveals that only 3 percent of the total number of clusters is in the largest tonnage-size category, greater than 10,000 short tons U₃O₈, and that 80 percent of the clusters are hosted by Triassic and Jurassic rocks. The distributions of grade and tonnage for clusters in the Powder River Basin show a wide variation; the grade distribution is highly variable, reflecting a difference between roll-front deposits and concretionary deposits, and the Basin contains about half the number in the greater-than-10,000 tonnage-size class as does the Colorado Plateau, even though it is much smaller. The grade and tonnage models should prove useful in finding the richest and largest uranium deposits.     

电感耦合等离子体质谱(ICP-MS)测定盐湖水中铀含量

利用电感耦合等离子体质谱(ICP-MS)技术,对比分析了直接稀释法和基体匹配法测定含盐水样中微量铀的精密度、准确度和回收率。结果表明,两种方法的铀标准曲线线性相关系数均大于0.999 9,精密度、准确度和回收率都满足样品测定要求,二者均可用于盐湖水中微量铀的测定。但基体匹配法稳定性高,重现性好,更适合于盐湖水中微量铀的快速、准确测定。     

The deposit size frequency method for estimating undiscovered uranium deposits

The deposit size frequency (DSF) method has been developed as a generalization of the method that was used in the National Uranium Resource Evaluation (NURE) program to estimate the uranium endowment of the United States. The DSF method overcomes difficulties encountered during the NURE program when geologists were asked to provide subjective estimates of (1) the endowed fraction of an area judged favorable (factorF) for the occurrence of undiscovered uranium deposits and (2) the tons of endowed rock per unit area (factorT) within the endowed fraction of the favorable area. Because the magnitudes of factorsF andT were unfamiliar to nearly all of the geologists, most geologists responded by estimating the number of undiscovered deposits likely to occur within the favorable area and the average size of these deposits. The DSF method combines factorsF andT into a single factor (F·T) that represents the tons of endowed rock per unit area of the undiscovered deposits within the favorable area. FactorF·T, provided by the geologist, is the estimated number of undiscovered deposits per unit area in each of a number of specified deposit-size classes. The number of deposit-size classes and the size interval of each class are based on the data collected from the deposits in known (control) areas. The DSF method affords greater latitude in making subjective estimates than the NURE method and emphasizes more of the everyday experience of exploration geologists. Using the DSF method, new assessments have been made for the young, organic-rich surficial uranium deposits in Washington and idaho and for the solution-collapse breccia pipe uranium deposits in the Grand Canyon region in Arizona and adjacent Utah.     

阿拉尔河悬浮物对铀的吸附影响研究

为了解阿拉尔河悬浮物对铀的吸附特性,通过静态吸附实验,研究了吸附时间、pH值、温度和铀初始浓度等因素对模拟含铀水中U(VI)去除率的影响,并从热力学和动力学方面对吸附过程进行了分析。结果表明,在T=25℃,溶液初始pH=7,接触时间为16 h时,悬浮物对铀的平衡吸附率最佳,为95.48%。随着铀初始浓度的增加,吸附量增加,但吸附率随之下降,升高温度有利于铀的吸附。铀在悬浮物上的吸附过程符合Langmuir等温吸附方程,说明悬浮物对铀为单分子层吸附,且化学吸附占主导地位。吸附动力学过程可用准二级吸附动力学模型描述,表明吸附主要受动力学控制,由两个以上步骤共同控制。FTIR和EDS分析结果表明,吸附过程中铀主要与悬浮物表面活性基团螯合并以表面络合吸附为主。吸附前后的能谱对比分析表明,吸附过程中存在离子交换行为。因此,悬浮物对铀的吸附机理是以表面络合吸附和离子交换为主、物理吸附为辅的混合吸附过程。     

Mesostructural and microstructural evidences for a two stage tectono-metallogenetic model for the uranium deposit at Mika, Northeastern Nigeria: A research note

The Mika uranium deposit is of the Central Massif vein-type. The deposit consists of a series of subparallel veins, similar to Lilljuthatten deposit (Sweden), with variable ore grade. Two main structural trends occur within the vicinity of Mika namely: (1) vertical N160E-N180E or N-S normal fault trend in which the brecciated granite has been permeated and cemented by silica ribbons; (2) N130E trend associated with reddish brown hematitized siliceous breccias filling open fractures. The N130E trend is younger, and it is a local, passive shear trend developed at the bends of the N-S faults. On a microscopic scale, samples from the N-S trend are rich in crude cubic-tetragonal prismatic crystals of uraninite and/or pitchblende ores occurring in association with a low-temperature greenschist mineral assemblage of chlorite, epidote, and mica. Conversely, samples from the N130E trend show widespread kaolinitisation, goethite formation and layering reminiscent of groundwater activity at shallow depths near the earth’s surface. The main uranium mineral in this zone is yellowish autunite. The model proposed here envisages that the mineralization was related to two separate processes. A first mineralization episode developed simultaneous with the greenschist mineral assemblage, and a second episode was related to remobilization and subsequent mineral concentration in the passive N130E open fractures by groundwater to form autunite. Such a model has far reaching implications for exploration. Although the secondary minerals along the N130E fractures are more obvious in the field, the potentially economic primary mineral concentrations may be concealed at greater depth in the N-S structures.     

阿拉尔河下游沉积物对铀的动态吸附机制

采用动态吸附法,研究流速、沉积物粒径、沉积物投加量、铀初始浓度等对阿拉尔河下游沉积物吸附铀的影响,并结合Thomas模型及表征数据对吸附机理进行探讨。结果表明,动态吸附饱和时间与流速、沉积物粒径及铀初始浓度呈反相关,与沉积物投加量呈正相关。总饱和吸附量与流速及沉积物粒径呈反相关,与沉积物投加量及铀初始浓度呈正相关。沉积物对铀的动态吸附符合Thomas模型,吸附过程由多个步骤共同控制,吸附速率受多个因素的共同影响。吸附的主要机制为表面络合反应,并伴有离子交换作用。     

A New Model for Heat Flow in Extensional Basins: Estimating Radiogenic Heat Production

Radiogenic heat production (RHP) represents a significant fraction of surface heat flow, both on cratons and in sedimentary basins. RHP within continental crust—especially the upper crust—is high. RHP at any depth within the crust can be estimated as a function of crustal age. Mantle RHP, in contrast, is always low, contributing at most 1 to 2 mW/m² to total heat flow. Radiogenic heat from any noncrystalline basement that may be present also contributes to total heat flow. RHP from metamorphic rocks is similar to or slightly lower than that from their precursor sedimentary rocks. When extension of the lithosphere occurs—as for example during rifting—the radiogenic contribution of each layer of the lithosphere and noncrystalline basement diminishes in direct proportion to the degree of extension of that layer. Lithospheric RHP today is somewhat less than in the distant past, as a result of radioactive decay. In modeling, RHP can be varied through time by considering the half lives of uranium, thorium, and potassium, and the proportional contribution of each of those elements to total RHP from basement. RHP from sedimentary rocks ranges from low for most evaporites to high for some shales, especially those rich in organic matter. The contribution to total heat flow of radiogenic heat from sediments depends strongly on total sediment thickness, and thus differs through time as subsidence and basin filling occur. RHP can be high for thick clastic sections. RHP in sediments can be calculated using ordinary or spectral gamma-ray logs, or it can be estimated from the lithology.     

RESIDENTIAL MOBILITY: THE IMPACTS OF WEB-BASED INFORMATION ON THE SEARCH PROCESS AND SPATIAL HOUSING CHOICE PATTERNS

In the past few years, a vastly enriched information source on housing vacancies has become available through real estate industry-sponsored sites on the Internet. This rich information source has the potential to influence spatial patterns and processes in the search for housing by eliminating information barriers in the search process. Thirty years ago, geographers documented the constraints to the search process caused by limited or biased information fields. The question addressed by this research was whether this new information availability would change the search patterns documented in the 1970s. In order to investigate this question recent movers in Wake County, North Carolina, were surveyed in early 2000, and the characteristics of Web users were compared with nonusers. The major finding of this research is that to date, the Internet has had little impact on search patterns, except that those using the Internet tend to visit a larger number of houses personally than those who do not use the World Wide Web as an information source. [Key words: residential mobility, housing search, Internet.]     

An integrated data-directed numerical method for estimating the undiscovered mineral endowment in a region

An integrated data-directed numerical method has been developed to estimate the undiscovered mineral endowment within a given area. The method has been used to estimate the undiscovered uranium endowment in the San Juan Basin, New Mexico, U.S.A. The favorability of uranium concentration was evaluated in each of 2,068 cells defined within the Basin. Favorability was based on the correlated similarity of the geologic characteristics of each cell to the geologic characteristics of five area-related deposit models. Estimates of the undiscovered endowment for each cell were categorized according to deposit type, depth, and cutoff grade. The method can be applied to any mineral or energy commodity provided that the data collected reflect discovered endowment.     

Analysis of spatial patterns of public attention on housing prices in Chinese cities: A web search engine approach

Housing price has become one of the most pressing issues facing urban residents in China in recent years and received considerable attention. However, detailed housing price data are often ill-documented or unavailable for the public, thus posing a grand challenge for the study of housing prices in China. Because individuals' Internet search activities can be recorded by web search engines, the analysis of these web search activities in cyber-space may provide a means of better understanding public attention and associated concerns in real geographic space. In this study, we focus on exploring the spatial patterns of public attention on housing price through the analysis of web query activities based on Baidu Index, a Chinese keyword analysis tool from Baidu web search engine. We propose a new index based on keyword query outcome from Baidu search database to analyze spatially heterogeneous patterns of housing price attention from 19 large and medium-sized cities in China. We evaluate the spatial network structure of housing price attention, and develop a new index to measure the intensity of interaction relationships among cities of interest. Our results show that spatial interactions of housing price attention between cities evaluated using the new method are consistent with those from a gravity model. Meanwhile, as revealed from Baidu Index-based indicators, strong spatial association patterns exist among cities that form urban agglomerations. Further, our results demonstrate that the web search engine approach, based on the coupling of cyber-space and geographic space, provides solid support for the study of housing price attention and its spatially explicit patterns in China.     

Access routes to high mountain huts facing climate-induced environmental changes and adaptive strategies in the Western Alps since the 1990s

ABSTRACT

In the European Alps, high mountain environments are subject to major impacts resulting from climate change, which strongly affect human activities such as mountaineering. The purpose of the study was to examine changes in access routes to 30 high mountain huts in the Western Alps since the 1990s. Data were derived from the use of two different methods, geo-historical studies and a questionnaire, and were used to identify both the climate-related processes affecting the climbing routes and the strategies implemented by public entities, Alpine clubs, guide companies, and hut keepers to maintain acceptable safety and technical conditions. The case studies revealed issues affecting three access routes and the results from the questionnaire showed that the main processes affecting access routes were loss of ice thickness and retreat from the front of the glaciated areas. Commonly, in situ equipment was installed to facilitate access for mountaineers and/or a part of a route was relocated to a safer area. The authors conclude that in most cases, the measures were effective but they were limited by financial, ethical and legal issues, especially in protected or classified areas that could jeopardise their durability and effectiveness.