The Export Potential of Colombian Coal

Colombian coal-exporting capacity is examined in terms of the country's advantageous location with regard to potential markets, coal reserves and development plans. By the year 2000 Colombia could have the capacity to export 40 million tonnes of coal per annum.     

煤矿生产与环境保护

本文对煤矿生产过程中所存在的一些主要环境污染源及其控制技术进行了详细的论述。并对煤矿开采与环境保护的协调发展进行了讨论。     

Restoring Forests and Associated Ecosystem Services on Appalachian Coal Surface Mines

Surface coal mining in Appalachia has caused extensive replacement of forest with non-forested land cover, much of which is unmanaged and unproductive. Although forested ecosystems are valued by society for both marketable products and ecosystem services, forests have not been restored on most Appalachian mined lands because traditional reclamation practices, encouraged by regulatory policies, created conditions poorly suited for reforestation. Reclamation scientists have studied productive forests growing on older mine sites, established forest vegetation experimentally on recent mines, and identified mine reclamation practices that encourage forest vegetation re-establishment. Based on these findings, they developed a Forestry Reclamation Approach (FRA) that can be employed by coal mining firms to restore forest vegetation. Scientists and mine regulators, working collaboratively, have communicated the FRA to the coal industry and to regulatory enforcement personnel. Today, the FRA is used routinely by many coal mining firms, and thousands of mined hectares have been reclaimed to restore productive mine soils and planted with native forest trees. Reclamation of coal mines using the FRA is expected to restore these lands’ capabilities to provide forest-based ecosystem services, such as wood production, atmospheric carbon sequestration, wildlife habitat, watershed protection, and water quality protection to a greater extent than conventional reclamation practices.     

Thermodynamic Controls on Quality of Water From Underground Coal Mines in Colorado1

ABSTRACT: Water samples collected from 14 underground coal mines in Colorado were analyzed for major dissolved constituents. The data indicate the water quality of 13 of the samples has developed by the interaction of calcite saturated ground water with sodium rich marine shales. Those samples that displayed evidence of being most completely reacted were composed almost entirely of sodium and bicarbonate ions and had a calcium to sodium activity ratio of 0.16, similar to that of seawater. The one sample that was not saturated with respect to calcite was saturated with respect to gypsum. The dissolved solids concentration attainable by dissolution of gypsum is much less than that attainable by the calcite marine shale equilibration, or approximately 2,500 milligrams per liter. By considering the maximum predicted concentrations of dissolved solids in relation to promulgated water quality criteria, it is possible to predict the hazards of reuse of this mine drainage. The primary problems would be damage or destruction of crops if the drainage water was used for irrigation. In addition, some samples contained concentrations of chloride and sulfate in excess of recommended standards for public water supplies.     

A Comparison of Urban-Proximate and Urban-Distant Wilderness Users on Selected Variables

/ The underlying premise of this study is that wilderness areas attract visitors desiring or expecting different wilderness experiences. In this study, wilderness areas were dichotomized according to distance from a large urban center (urban-proximate vs urban-distant). Four wilderness areas in southern California were used as the study sites. Comparisons were made on selected attributes commonly associated with the wilderness experience. Differences were observed on a number of variables such as acceptable number and type of encounters with other visitors, management preferences, and preferred group sizes. The findings of this study are congruent with those from previous studies and suggest that distance to large urban centers may be a functional variable in explaining differences among selected wilderness attributes.KEY WORDS: Expectancy theory; Normative standards; Wilderness; Wilderness experience; Urbanization     

贵州小型煤矿整合环境影响评价探讨

本文通过对贵州省历次小型煤矿关闭与整合遗留环境问题的总结,结合新一轮煤矿关闭整合的特点和环评要求,通过以老带新、保留和增加环保措施、改进生产工艺、提高管理水平等环境管理对策,解决煤矿环境问题.     

Initial Screening of Contaminated Land: A Comparison of US and Swedish Methods

Preliminary surveys are used to prioritize between contaminated sites to select those to be investigated more thoroughly. The data-gathering steps are almost identical between countries; however, the assessment procedures differ significantly. In this study, we have investigated 21 contaminated sites assessed as belonging to the high-risk or the very high-risk class using the Swedish Methods for Inventories of Contaminated Sites (MICS). We then applied the US Preliminary Assessment (PA) method to the same sites and compared the results and conclusions from the two screening procedures. In both cases, all sites were recommended for further investigation and the two approaches seem to corroborate one another; however, the PA assessment scores and the preliminary MICS classifications did not correlate. The results obtained with the PA method were easier to explain than the final MICS classification. The PA method also seems more transparent and easier to standardize, although objections could be made regarding the weighting scheme, because the outcome in this study was entirely dependent on the surface exposure pathway. However, to examine this in greater detail, it is necessary to include sites with less contamination: The importance of preliminary surveys in the overall risk management process gives a strong motivation for such an evaluation. Generally, the lack of research and scientific support for the various assessment procedures in use suggests that there is a need for method development, standardization, and validation.     

Small Gold Mines — The Production and Declaration Problem: Another Dilemma for a Small Developing Country*

The under-reporting of gold production in small developing countries denies these countries an important source of foreign exchange. This paper examines the problem in a Guyanese context, and suggests a series of measures to deal with the problem.     

基于Adaboost集成BP网络原煤生产成本预测研究

为了提高传统BP神经网络预测模型精度,避免BP网络容易陷入局部极值、收敛速度慢等问题,将BP神经网络与Ada-boost算法相结合,提出了一种Adaboost集成BP神经网络模型.结合磁县观台煤矿原煤生产成本相关数据,建立了原煤生产成本预测的Adaboost集成BP神经网络模型,将该模型用于实际的原煤成本预测.结果表明：该模型预测精度高于传统的BP神经网络,收敛速度快,具有较强的鲁棒性,预测精度能满足实际预测需要,为原煤生产成本预测提供了一种新的途径,也为原煤生产成本控制提供了重要依据.     

川北高台原区废弃煤矿枯水期矿井涌水水化学特征及成因分析

对废弃煤矿矿井涌水的水化学特征及成因进行分析,可为保护矿区地下水环境提供理论支撑.基于地质背景,通过对比枯水季节川北高台原区废弃煤矿矿井涌水与背景泉点水化学指标,并采用聚类分析方法对矿井涌水中离子指标进行统计,进而对其特征及成因进行了研究.结果表明:地层中黄铁矿中硫元素氧化是矿井涌水水化学特征变化的开端,受研究区矿井涌...     

国内外生态旅游研究现状比较

以中国知网全文期刊数据库和Google学术搜索为数据来源,通过文献综述法对国内外现有的生态旅游相关文献进行了综合分析,在当前的生态旅游研究基础上从其产生背景入手,对比分析国内外生态旅游研究在概念界定及发展现状上的异同,借鉴国外经验,为我国未来的生态旅游研究提出建设性建议.     

低成本海水淡化集成技术探讨

海水淡化集成技术以低温多效蒸馏海水淡化为核心,联合热电与盐碱化工,形成"热-电-水-盐"四联产模式,实现淡水资源、海水资源以及能源的综合利用,大幅降低生产成本,并取得环保效益、社会效益。为未来向城市供水提供了一条现实可行的方案。     

Sources and Distribution of Polychlorinated Terphenyls at a Major US Aeronautics Research Facility

O -deethylase (EROD) activity to a similar degree as PCB Aroclor 1254 and to a greater extent than PCT Aroclor 5460. The presence of high concentrations of PCTs contributed to the facility being included on the National Priorities List. It subsequently became the first US federal facility to sign a Federal Facility Agreement, identifying cleanup responsibilities, prior to formal listing.     

Selenium Bioaccumulation in Stocked Fish as an Indicator of Fishery Potential in Pit Lakes on Reclaimed Coal Mines in Alberta, Canada

Pit lakes are a common reclamation strategy for open pit mines; however, there is a concern about their water quality and suitability as fish habitat because they are often contaminated by metals or metalloids. This study assessed the exposure of fish and invertebrates to selenium (Se) and other metals and metalloids in pit lakes formed by open pit coal mining in Tertiary (thermal coal) and in Cretaceous (metallurgical coal) bedrock. Juvenile hatchery rainbow trout, Oncorhynchus mykiss, and brook trout, Salvelinus fontinalis, were stocked into two thermal coal pit lakes (water Se < 2 μg/L, low water Se) and two metallurgical coal pit lakes (water Se > 15 μg/L, high water Se). Se accumulation in stocked fish and concentrations in invertebrates were characterized over a period of 2 years. In the metallurgical pits, invertebrates had higher Se concentrations and fish accumulated Se to higher levels (exceeding USEPA tissue Se guidelines) than biota in the thermal pits. Rainbow and brook trout accumulated similar concentrations of Se in their muscle and exhibited a similar relationship between whole-body and muscle Se concentrations. These results may be used by resource managers to assess compliance with whole-body tissue Se guidelines and to determine if pit lakes in coal mining areas pose a significant Se risk to wildlife or human health. The high Se exposure in metallurgical coal pits indicates that under the current mining and reclamation strategy, these lakes are not suitable for management as recreational “put and take” fisheries.     

Use of Artificial Roost Structures by Bats at the Indianapolis International Airport

From 1992–1996, 3204 artificial roosts of 9 types were placed in woodlots near Indianapolis International Airport in an effort to provide habitat for the federally-endangered Indiana myotis (Myotis sodalis) and to determine the feasibility of using these structures to manage bats in a rapidly developing suburban area. We surveyed these structures at least annually during 1992–1999 and found only northern myotis (Myotis septentrionalis) regularly using the structures. Four other species were occasionally found using structures including big brown bats (Eptesicus fuscus, n = 14 individuals), little brown myotis (Myotis lucifugus, n = 2), Indiana myotis (Myotis sodalis, n = 2), and one silver-haired bat (Lasionycteris noctivagans). Single, triple, and Missouri-style batboxes were almost always used, rather than the six other types of experimental roosts that had been in place. However, after 10 years in place, it appears that Indiana bats are acclimated to boxes, as 6 of them were being used rather regularly by Indiana myotis. Bat boxes can provide roosting habitat for some species under conditions where few suitable roosts exist, but assuring an abundance of natural habitats is usually more desirable for conservation of tree-roosting bats.     

适宜性评价视角下的煤矿土地复垦技术措施研究——以白山市道清沟煤矿为例

基于土地适宜性评价方法,着重选取极限值条件法、AHP层次分析法、加权指数和法对白山市道清沟煤矿区的土地适宜类和土地质量等进行系统综合的分析,判定道清沟煤矿待复垦土地的类型、数量和质量。基于土地破坏现状和适宜性评价结果,提出以工程措施为主、生物化学措施为辅助的土地生态重构对策。     

水泥工业原料的开发利用

本文从综合利用资源的角度出发,介绍了利用部份低品位矿产生产水泥工业原料、水泥产品具有显著的经济效益和社会效益。     

Modelling the conversion of Colombian lowland ecosystems since 1940: drivers, patterns and rates

In biologically mega-diverse countries that are undergoing rapid human landscape transformation, it is important to understand and model the patterns of land cover change. This problem is particularly acute in Colombia, where lowland forests are being rapidly cleared for cropping and ranching. We apply a conceptual model with a nested set of a priori predictions to analyse the spatial and temporal patterns of land cover change for six 50-100 km(2) case study areas in lowland ecosystems of Colombia. Our analysis included soil fertility, a cost-distance function, and neighbourhood of forest and secondary vegetation cover as independent variables. Deforestation and forest regrowth are tested using logistic regression analysis and an information criterion approach to rank the models and predictor variables. The results show that: (a) overall the process of deforestation is better predicted by the full model containing all variables, while for regrowth the model containing only the auto-correlated neighbourhood terms is a better predictor; (b) overall consistent patterns emerge, although there are variations across regions and time; and (c) during the transformation process, both the order of importance and significance of the drivers change. Forest cover follows a consistent logistic decline pattern across regions, with introduced pastures being the major replacement land cover type. Forest stabilizes at 2-10% of the original cover, with an average patch size of 15.4 (+/-9.2)ha. We discuss the implications of the observed patterns and rates of land cover change for conservation planning in countries with high rates of deforestation.     

国内外的潜水搅拌机和倒伞曝气机能效比较

本文对国内外污水处理设备中的潜水搅拌器（机）和倒伞曝气机在能耗和效率方面进行了对比，应用实践证明，国产污水处理设备的能效比远远优于引进及仿制的国外同类产品。