首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
This article attempts to study both returns to scale and optimal size of production. Specifically, the authors estimate a ray-homothetic production function which allows the returns to scale to vary with ouput size and input mix. The production model is estimated using data from the Welsh coal industry for the period 1961–1976. Findings showed that, first, the Welsh coal industry suffers from a level of production which is either too small or below its optimal level and, second, this discrepancy between actual and optimal production worsened over the period considered.  相似文献   

2.
Increasing productivity of open-cut mines in New South Wales and Queensland has been an important element in the expansion of the Australian black coal industry, which now supplies domestic electricity and iron and steel industries as well as increasing export orders. Industry is capable of strong growth but some changes in government policies are needed to ensure that infrastracture is provided and growth is economically efficient and compatible with environmental considerations. Increasing output is likely to prevent the reemergence of manpower problems which once plagued the industry, but such problems could surface if growth is not maintained.  相似文献   

3.
Comparison of labour productivities and wage-to-price ratios suggests that the Coal Board's behaviour was not profit-maximizing. This does not make the use of production functions to determine optimal scale very relevant. In particular, the current debates about efficiency and closures cannot be approached solely or mainly from production function analysis.  相似文献   

4.
The desire of oil companies operating in the Niger Delta to secure their social license to operate, and address their community development obligations, has led in recent years to the adoption of corporate social responsibility (CSR) policies and strategies. Drawing on quantitative and qualitative data collected in host communities within the Niger Delta in Nigeria, the paper compares the effectiveness of two different corporate–community involvement strategies. The evidence suggests that while the corporate–community foundation model has certain advantages over the in-house community investment model, both approaches suffer from a common shortcoming that limits the impact of oil companies’ efforts on community development in their host communities. The paper concludes by exploring the implications of the research findings for corporate–community involvement in the Nigerian oil industry.  相似文献   

5.
Economic analysis of reform policies for small coal mines in China   总被引:2,自引:0,他引:2  
Over the last three decades, China’s coal industry has achieved dramatic increases in coal production, both in absolute terms and relative to the world as a whole. This achievement is due largely to its coal policies. Yet facing increasing pressures of environmental sustainability and market transition, the Chinese government was forced to make deep reforms and adjustments to regulate the coal industry effectively. This paper presents an historical overview of China’s coal economic policies, paying particular attention to the current reform policy of closing mines and restricting the yield for the small coal mines (SCMs) in the context of economic theories and methods. We argue that the SCM closure policy would not likely be efficiently enforced if a feasible market mechanism were not built up. The failure of closure policy is due largely to problems of property rights, coal pricing, ownership, and objectives.  相似文献   

6.
Carbon-enriched fractions have been obtained from two coal fly ash (FA) samples. The FA came from two pulverized-coal fired power stations (Lada and Escucha, Spain) and were collected from baghouse filters. Sieving was used to obtain carbon-enriched fractions, which were further subjected to two beneficiation processes: acid demineralization using HCl and HF, and oil agglomeration using soya oil-water. Yield in weight after sieving, unburned carbon content, and several physicochemical characteristics of the obtained fractions were used to compare the performance of the beneficiation methods. Low carbon concentration was obtained by sieving, particularly in the case of Escucha FA. However, after acid demineralization or oil agglomeration, fractions containing unburned carbon in a range of 63% to 68% were obtained. These fractions showed differences in mineral phase composition and distribution depending on the FA and on the beneficiation method used. The textural properties of the obtained fractions varied as a function of their carbon content and the beneficiation method used. However, no significant differences in morphology of the carbonaceous particles were found.  相似文献   

7.
A full-scale field study was carried out at two Spanish coal-fired power plants equipped with electrostatic precipitator (ESP) and wet flue gas desulfurisation (FGD) systems to investigate the distribution of boron in coals, solid by-products, wastewater streams and flue gases. The results were obtained from the simultaneous sampling of solid, liquid and gaseous streams and their subsequent analysis in two different laboratories for purposes of comparison. Although the final aim of this study was to evaluate the partitioning of boron in a (co-)combustion power plant, special attention was paid to the analytical procedure for boron determination. A sample preparation procedure was optimised for coal and combustion by-products to overcome some specific shortcomings of the currently used acid digestion methods. In addition boron mass balances and removal efficiencies in ESP and FGD devices were calculated. Mass balance closures between 83 and 149% were obtained. During coal combustion, 95% of the incoming boron was collected in the fly ashes. The use of petroleum coke as co-combustible produced a decrease in the removal efficiency of the ESP (87%). Nevertheless, more than 90% of the remaining gaseous boron was eliminated via the FGD in the wastewater discharged from the scrubber, thereby causing environmental problems.  相似文献   

8.
The demand for washed coal in India has led to the planning of washeries. The sources of air pollution in washeries are described is this paper. A number of new washeries are going to be installed within the vicinity of Jharia Coalfield in eastern India to fulfill the demand for washed coal. Air pollution monitoring was conducted at four coal washeries of Bharat Coking Coal Ltd. (BCCL). Methods adopted for selection of monitoring stations and sampling and analysis of ambient air quality are discussed. Suspended particulate matter (SPM) concentrations in an industrial area, a residential area, and a sensitive area such as a hospital were found to be high and to exceed the limit specified by the Indian Pollution Control Board. NOx and SO2 concentrations in some areas were also found to exceed the specified limits. A high percentage of respirable dust in SPM indicates a health hazard. Benzene-soluble material was found to be 40%, which can be fatal to human health. Suppression measures are discussed for dust, and control measures for air pollution in coal washeries are proposed.  相似文献   

9.
Finance and investment, technological development, government legislation and fiscal policies, public attitudes and aboriginal lands, are among the major issues confronting the Australian minerals industry. Within this context the author discusses the significance of the industry to the Australian economy and assesses its potential.  相似文献   

10.
Throughout history, mining communities have invariably found themselves striving for a good quality of life and a long‐term future. In the 21st century, problems of maintaining the economic vitality of mining regions are now compounded by concerns about the biophysical integrity of the local environment. In regions of the world where the economic viability of the resource is marginal and achieving a reasonable quality of life is a daily struggle, sustainable mining may seem to be a dubious prospect at best. Yet the twin imperatives of global political forces and burgeoning environmental concerns are requiring industry, governments and other interests to re‐conceptualize the way in which mining takes place in communities. Although mining itself may not be seen as an industry that contributes to the achievement of environmental objectives, it could — with careful planning — be used as a tool to foster a more sustainable and healthier community. This argument is considered in the context of the coal mining region of Santa Catarina, Brazil.  相似文献   

11.
Environmentalism and elitism: a conceptual and empirical analysis   总被引:2,自引:0,他引:2  
The frequent charge that environmentalism is elitist is examined conceptually and empirically. First, the concept of elitism is analyzed by distinguishing between three types of accusations made against the environmental movement: (a)compositional elitism suggests that environmentalists are drawn from privileged socioeconomic strata, (b)ideological elitism suggests that environmental reforms are a subterfuge for distributing benefits to environmentalists and/or costs to others, and (c)impact elitism suggests that environmental reforms, whether intentionally or not, do in fact have regressive social impacts.The evidence bearing on each of the three types of elitism is examined in some detail, and the following conclusions are drawn: Compositional elitism is an exaggeration, for although environmentalists are typically above average in socioeconomic status (as are most sociopolitical activists), few belong to the upper class. Ideological elitism may hold in some instances, but environmentalists have shown increasing sensitivity to equity concerns and there is little evidence of consistent pursuit of self-interest. Impact elitism is the most important issue, and also the most difficult to assess. It appears that there has been a general tendency for environmental reforms to have regressive impacts. However, it is increasingly recognized that problems such as workplace pollution and toxic waste contamination disproportionately affect the lower socioeconomic strata, and thus reforms aimed at such problems will likely have more progressive impacts.This is Michigan Agricultural Experiment Station Journal article no. 11508.  相似文献   

12.
Chile and Peru produce almost 45% of world’s mine copper output. This situation reflects their natural endowment and mining tradition, but is also the result of development processes undertaken over the last decades. As a result, both countries multiplied its mine copper production in more than 3 times in the last 20 years. Mining labor productivity played a central role achieving these amazing growth rates. Although there is a consensus about the relevance of this variable for the mining industry, the specific factors behind labor productivity changes are not completely understood.  相似文献   

13.
This study presents the results of a laboratory investigation conducted to evaluate the efficiency of coal fly ash to control the formation of acid mine drainage (AMD) from mine waste. Site-specific materials, coal fly ash from Atikokan Thermal Generating Station and mine tailings from Musselwhite mine, were mixed at different proportions for the investigation of the drainage chemistry and the optimal mix using static testing (acid–base accounting) and kinetic (column) testing. The acid–base accounting (ABA) results indicated that the fly ash possessed strong alkaline (neutralization) potential (NP) and could be used in the management of reactive mine tailings, thus ensuring prevention of AMD in the long-term. Column tests conducted in the laboratory to further investigate long-term performance of fly ash in the neutralization and prevention of acid mine drainage from tailings similarly showed that mixing fly ash with mine tailings reduces dissolution of many heavy metals from tailings by providing alkalinity to the system. It was found that a fly ash to tailings mass ratio equal to or greater than 15% can effectively prevent AMD generation from Musselwhite mine tailings in the co-placement approach.  相似文献   

14.
Characteristics of coal mine ventilation air flows   总被引:2,自引:0,他引:2  
Coal mine methane (CMM) is not only a greenhouse gas but also a wasted energy resource if not utilised. Underground coal mining is by far the most important source of fugitive methane emissions, and approximately 70% of all coal mining related methane is emitted to the atmosphere through mine ventilation air. Therefore, research and development on mine methane mitigation and utilisation now focuses on methane emitted from underground coal mines, in particular ventilation air methane (VAM) capture and utilisation. To date, most work has focused on the oxidation of very low concentration methane. These processes may be classified based on their combustion kinetic mechanisms into thermal oxidation and catalytic oxidation. VAM mitigation/utilisation technologies are generally divided into two basic categories: ancillary uses and principal uses. However, it is possible that the characteristics of ventilation air flows, for example the variations in methane concentration and the presence of certain compounds, which have not been reported so far, could make some potential VAM mitigation and utilisation technologies unfeasible if they cannot cope with the characteristics of mine site ventilation air flows. Therefore, it is important to understand the characteristics of mine ventilation air flows. Moreover, dust, hydrogen sulphide, sulphur dioxide, and other possible compounds emitted through mine ventilation air into the atmosphere are also pollutants. Therefore, this paper presents mine-site experimental results on the characteristics of mine ventilation air flows, including methane concentration and its variations, dust loadings, particle size, mineral matter of the dust, and other compounds in the ventilation air flows. The paper also discusses possible correlations between ventilation air characteristics and underground mining activities.  相似文献   

15.
This paper builds on past behavioural research which explicitly recognises that ‘actions’ are preceded by ‘intentions’ which are in turn determined by individual mindsets, locus of control, principles of governances and context factors. More concretely, it presents a model that investigates the extent to which environmental behavioural intentions are explained by i) managers' core values, basic assumptions, and beliefs, ii) individual and socio-cognitive frames, iii) principles of governance, and iv) context factors. Context factors include obstacles and drivers of greener behaviours, market pressures, and firm demographics. The resulting theoretical framework is tested empirically through regression analyses that use data gathered from a survey of 536 Argentinean firms in polluting industries. The model performs well, explaining approximately 50% of the variations in the (pro) environmental behaviour of firms. Policy implications are briefly discussed.  相似文献   

16.
In this paper, a real options based binominal lattices model for the investment of coal bed methane (CBM) is conducted. CBM prices and market demand are incorporated into the model as the predominant uncertain factors and it is solved by using the bidimensional binominal lattices approach. Then the model is employed to evaluate the investment in CBM projects in China, and the effect of related policies is analyzed. The empirical results demonstrate that the model can be used to offer a better explanation of why the CBM industry has developed slowly in China from an investment perspective. It is found that the current policy environment is not positive enough to attract investment in the CBM industry. Among various factors, CBM prices yield the most significant effect on stimulating investment in CBM development. Increasing the price subsidy is also an effective policy to stimulate investment and promote the development of the CBM industry in China.  相似文献   

17.
China's calcium carbide output has dominated the global market for several years, driven by the demand for PVC (polyvinyl chloride), a fundamental polymer material and also the primary downstream product of calcium carbide in China. The fast growth of this energy-intensive industry leads to an inevitable increase in CO2 emissions. However, there is a large reduction potential with process improvement in this industry which is currently characterized by widespread outdated facilities. In this study, we attempt to assess the reduction potential of CO2 emissions in China's calcium carbide production, based on the analysis of CO2 emission patterns and estimation of the emission amount. Three scenarios regarding process improvement are employed to conduct this assessment. The results imply that the cumulative CO2 abatement in the Current Policy Scenario and in the Strengthened Policy Scenario from 2008 to 2020, compared with the Baseline Scenario, are 89.0 and 107.6 million t, respectively. The specific measures and policy implications to achieve this potential are also discussed in the article.  相似文献   

18.
19.
20.
The relationship between people and places is characterized by affective and cognitive dimensions, defined, respectively, as place attachment and identification. This paper aims at clarifying differences between place attachment and identification by (1) identifying their predictors in a structural equation model and (2) exploring their association with the environmental perception. To this purpose, we conducted a research on a sample of 328 residents of a city in the north of Italy. Results show that the affective and the cognitive dimensions (1) are directly predicted by different demographical and psychosocial variables and (2) are strictly associated to the perception of the place and its inhabitants. Place attachment and identification are two distinct but correlated components. Semantic contents related to the environmental perception are described in respect to different levels of attachment and identification.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号