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291.
Strategies for sustainable development of the small-scale gold and diamond mining industry of Ghana 总被引:1,自引:0,他引:1
The small-scale gold and diamonds mining industry is of great importance to Ghana. Since its regularization in 1989 the sector has produced and sold over 1.5 million troy ounces of gold and 8.0 million carats of diamonds. During the same period the sector also provided direct employment to over 100,000 people and improved the socioeconomic life of many individuals and communities. However, these were largely achieved at a cost to the environment in areas where mining is carried out and there is the need to develop the industry in a sustainable manner. This paper looks at the developments in the small-scale gold and diamonds mining industry in Ghana and proposes some strategies on how the concepts of sustainable development could be applied to the industry. 相似文献
292.
针对煤粉锅炉一次风管堵塞的现象,指出了易堵塞的部位。分析了造成堵塞的原因,提出了疏通处理方法和应注意的问题。 相似文献
293.
介绍了新疆八一钢铁公司高炉烟煤的特点,指出了喷煤系统存在的缺陷,总结了高炉喷吹烟煤所采取的安全措施。 相似文献
294.
295.
Lakes caused by coal mining processes are characterized by low pH, low nutrient status, and high concentrations of Fe(II) and sulfate due to the oxidation of pyrite in the surrounding mine tailings. Fe(III) produced during Fe(II) oxidation precipitates to the anoxic acidic sediment, where the microbial reduction of Fe(III) is the dominant electron-accepting process for the oxidation of organic matter, apparently mediated by acidophilic Acidiphilium species. Those bacteria can reduce a great variety of Fe(III)-(hydr)oxides and reduce Fe(III) and oxygen simultaneously which might be due to the small differences in the redox potentials under low pH conditions. Due to the absence of sulfide, Fe(II) formed in the upper 6 cm of the sediment diffuses to oxic zones in the water layer where itcan be reoxidized by Acidithiobacillus species. Thus, acidic conditions are stabilized by the cycling of iron which inhibits fermentative and sulfate-reducing activities. With increasing sediment depth, the amount of reactive iron decrease, the pH increases above 5, and fermentative and as yet unknown Fe(III)-reducing bacteria are also involved in the reduction of Fe(III). Sulfate is reduced apparently by the activity of spore-forming sulfate reducers including new species of Desulfosporosinus that have their pH optimum similar to in situconditions and are not capable of growth at pH 7. However, generation of alkalinity via sulfate reduction is reduced by the anaerobic reoxidation of sulfide back to sulfate. Thus, the microbial cycling of iron at the oxic-anoxic interface and the anaerobic cycling of sulfur maintains environmental conditions appropriate for acidophilic Fe(III)-reducing and acid-tolerant sulfate-reducing microbial communities. 相似文献
296.
Georgios E. Pavlikakis Vassilios A. Tsihrintzis 《Journal of the American Water Resources Association》2003,39(2):277-288
ABSTRACT: The Ecosystem Management (EM) process belongs to the category of Multi‐Criteria Decision Making (MCDM) problems. It requires appropriate decision support systems (DSS) where “all interested people” would be involved in the decision making process. Environmental values critical to EM, such as the biological diversity, health, productivity and sustainability, have to be studied, and play an important role in modeling the ecosystem functions; human values and preferences also influence decision making. Public participation in decision and policy making is one of the elements that differentiate EM from the traditional methods of management. Here, a methodology is presented on how to quantify human preferences in EM decision making. The case study of the National Park of River Nestos Delta and Lakes Vistonida and Ismarida in Greece, presented as an application of this methodology, shows that the direct involvement of the public, the quantification of its preferences and the decision maker's attitude provide a strong tool to the EM decision making process. Public preferences have been given certain weights and three MCDM methods, namely, the Expected Utility Method, Compromise Programming and the Analytic Hierarchy Process, have been used to select alternative management solutions that lead to the best configuration of the ecosystem and are also socially acceptable. 相似文献
297.
介绍了活性灭火剂(ACP)的历史发展、灭火原理、配方原则、对配方要求和使用场合。可使读者对ACP获得较全面的了解。 相似文献
298.
299.
泥石流输沙对小江中下游河床演变的影响 总被引:4,自引:1,他引:4
对小江中下游近90km河床及两岸泥石流进行了调查研究。得到:泥石流输沙年际和季节变化大;泥石流高强度的输沙造成小江河床特殊的平面和剖面特征;泥石流堵塞小江河道,对纵比降有再造作用;泥沙使小江河床以年均20cm~50cm速度抬升。 相似文献
300.