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1.
This paper discusses the current state and future prospects of backward production linkages to the manufacturing sector in the Angolan oil and gas industry. The paper finds that local value-added links are currently limited to labour and to a lesser degree in basic services. However, there is a realistic and strategic potential for local manufacturing linkages to expand in the oilfield services sector of the industry, which in turn can stimulate industrial development. For this to be achieved, the factors that are currently constraining the expansion and deepening of linkages have to be addressed, namely, a weak local content strategy, a weak local skills and industrial base and the integration of industrial and oil sector policies.  相似文献   

2.
The desorption of antimony, Sb(V), from two sediment samples by phosphate, carbonate, sulfate, chloride, and nitrate at pH 8 was examined. One highly contaminated sediment sample was taken from an Sb mine (Goesdorf, Luxembourg); the other sample was the certified reference material PACS-2 (marine sediment). Phosphate was found to have a strong mobilizing ability, whereas that of carbonate was in general weaker. For comparison, and to understand better the possible importance of individual components of the sediments, desorption experiments were performed on pure phases (i.e., hydrous oxides of Fe, Mn, and Al) and the clay minerals kaolinite and montmorillonite. In the cases of hydrous metal oxides, Sb(V) was most effectively desorbed by phosphate, followed by carbonate. Phosphate also desorbed Sb(V) from the clay minerals, whereas carbonate had no effect. The pH dependence of adsorption of Sb(V) in the absence and presence of carbonate revealed that adsorption densities were higher (except in the case of montmorillonite) in the absence of carbonate, suggesting a competition between carbonate and [Sb(OH)] for surface sites generally and a lowering of surface charge in the case of hydrous aluminum oxide. The observations are unlikely to be due to ionic strength effects because activity coefficients in the blank and spiked solutions differ by <4%. Desorption experiments on sediments with varying concentrations of phosphate and carbonate demonstrated that at environmentally relevant concentrations, desorption by phosphate is negligible, whereas the effect of carbonate is not. Sulfate, chloride, and nitrate generally had little effect. The proportion of Sb desorbed in blank experiments coincides with that mobilized in the first fraction of the Bureau Communautaire de Référence (BCR) sequential extraction (easily exchangeable and carbonate-bound fraction).  相似文献   

3.
A three-step sequencing batch reactor (SBR) was used for nutrient removal from synthetic wastewater with different glucose-organic acid mixtures (1/1). Acetic, butyric, propionic and citric acids were used as organic acids along with glucose. The operation consisted of anaerobic, anoxic and oxic (An/Ax/Ox) phases with durations of 2/1/4.5h. Sludge age was kept constant for 10 days. Phosphate release and uptake rates were determined for different glucose-organic acid mixtures in the feed wastewater. Maximum phosphate uptake (8.1mgPl(-1)h(-1)) and release rates (2.23mgPl(-1)h(-1)) were obtained with the glucose-citric acid mixture. The highest (96%) percent phosphate removal at the end of the nutrient removal cycle (7.5h) was also obtained with the glucose-citric acid mixture while the glucose-acetic acid mixture resulted in comparable percent phosphate removal (95%).  相似文献   

4.
Through linkage creation, commodity extraction has the capacity to support local industrial production and capabilities building. Drawing on the experience of supplying inputs into the East African gold mining industry, this paper examines the constraints experienced by local suppliers arising from the purchasing procedures of large mining corporations and specialist construction companies contracted to construct these mines. Lead firms become locked-in to particular ways of working which minimise the opportunities that local suppliers have in providing products and services. After reviewing the situation for local mining suppliers in East Africa, the paper examines ways in which lead firms, the suppliers themselves and others (governments and industry associations) can better support local supplier involvement.  相似文献   

5.
石油天然气开采业(稠油)清洁生产指标体系的研究   总被引:1,自引:3,他引:1  
本文给出了石油天然气开采业清洁生产审核的指标体系,可作为该行业清洁生产审核的主要依据。通过清洁生产审核,使我国相应的行业生产过程更加符合清洁生产的要求,使清洁生产工作标准化和规范化,并带动其他行业的清洁生产工作。其清洁生产指标经预测,可以反映当前我国石油天然气开采业的实际水平,为我国石油天然气开采业开展清洁生产审核工作,打下良好的技术基础。  相似文献   

6.
The US Bureau of Mines has investigated the resource potential of 201 phosphate mines and depositee in 28 market economy countries and 17 mines and deposits in the USSR and China. The 201 mines and deposits contain an estimated 34.2 billiong tonnes (t) of recoverable phosphate rock (at the demonstrated resource level), with Morocco and Western Sahara accounting for 61% (21 billion t) and with the USA accounting for 19% (6.4 billion t). The 17 mines and deposits evaluated in the USSR and China contain approximately 1.5 billion t of potentially recoverable phosphate rock. Potential annual capacity from low-cost, high-grade producing mines in the USA is estimated to decline significantly during the latter half of the next decade, and the US phosphate fertilizer industry will have to obtain phosphate rock by developing new, higher-cost, lower-grade mines or import phosphate rock to satisfy anticipated demand in the next century. Of the world's new production capacity that are likely to be developed over the next decade, slightly over one-third could be produced at an estimated 1981 cost of $40/t or less, and about two-thirds would cost in the $40 to $50 per tonne range (including a 15% rate of return). In comparison, most of the competing phosphate rock from producing mines in Morocco could be produced for less than $40/t.  相似文献   

7.
Revegetation was studied on stockpiled serpentine substrate. The native vegetation surrounding the revegetation site is annual grassland. The seed mixture applied to both subsoil and topsoil plots was largely ineffective for revegetation. No growth occurred in the subsoil plots and most of the growth in the topsoil plots was from indigenous seed. Phosphate application (100 kg P ha–1 as NaH2PO4 · H2O) to the topsoil plots resulted in a significant increase in total above-ground productivity. Annual legumes (mostlyLotus subpinnatus Lag.) and, to a lesser degree,Plantago erecta Morris responded to the added phosphate with an increased above-ground productivity. Other annual forbs and annual grasses showed no significant response. The legumes also increased in abundance. Mycorrhizal root colonization forPlantago was not significantly affected by phosphate application, but was lower in this disturbed serpentine site compared to other undisturbed serpentine annual grassland sites nearby.  相似文献   

8.
Remarkable changes are occurring within the economies of the USSR, China and India that are influencing mineral industry activities. These three countries account for a major share of world minerals production and consumption. Their domestic reforms may ultimately have a serious impact on the global mining industry. This paper examines the present status of the Soviet, Chinese and Indian mineral industries, and forecasts conditions to 2010. Long-term characteristics analysed include industrial production, intensity of use, consumption, mine and plant expansion and trade policy. Six metals are highlighted in the study – aluminium, copper, lead, nickel, steel and zinc.  相似文献   

9.
This article addresses the concepts of economies of scope and multiproduct production, subadditivity and transray convexity as it applies to the mining industry. The article goes on to expand these concepts to include the case of mining waste utilization. It discusses how the modification of mining wastes into a marketable product can develop a relationship across the cost functions of the modified mining waste and ore production and how this interrelationship affects the profit maximizing condition. It discusses four possible outcomes from mining waste modification and its development into marketable products on the profitability and production of ore by the firm. Finally, it discusses mining waste utilization effects on rehabilitation costs and the potential for a decrease in the adverse community effects due to mine closure.  相似文献   

10.
Quaternized agricultural by-products as anion exchange resins   总被引:3,自引:0,他引:3  
The objectives of this study were the chemical modification of readily available, low-cost agricultural by-products to anion exchange resins and the selection of the best modified by-product for further use in anion removal. Resins were prepared through the quaternization of a series of 12 agricultural by-products with N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHMAC). Phosphate ion adsorption assays were conducted at pH 7 in order to compare adsorption properties among the by-products. Quaternized corn stover showed the highest phosphorus adsorption at 0.66 mmole/g. Since corn stover exhibited the best uptake of phosphate ion, it was compared to a commercially available, cellulose-based anion exchange resin. Additionally, adsorption capacities of quaternized corn stover for arsenate, chromate, and selenate were evaluated and adsorption efficiencies were determined in simulated wastewater samples. Our results indicate that modified corn stover demonstrates good adsorption uptake for arsenate and selenate and especially for chromate.  相似文献   

11.
ABSTRACT: Principal U.S. phosphate production is from central Florida where mining, processing, and waste disposal practices intimately associate the industry with water resouces. Available radium-226 data from 1966 and from 1973–1976 in mined and unmined mincralized areas and nonmineralized areas in the primary study area in Polk, Hardee, Hillsborough, Manatee, and De Soto counties were studied using log-normal probability plots and nonparametric statistical tests for significant difference as functions of time, depth, and location. Plots of radium in the water table and Floridan aquifers for mineralized and nonmineralized areas indicate that neither phosphate mineralization nor the industry is a probable factor. For the Lower Floridan aquifer, three separate radium populations are indicated with geometric means of 0.7, 3, and 10 pCi/1. Geometric mean radium-226 content of the water table aquifer is 0.17 pCi/1. Radium in the Floridan aquifer in Manatee and Sarasota Counties is elevated relative to that in the water table and in other areas of Florida. For Sarasota County, geometric mean radium content of the water table is 15 pCi/l versus 7.5 pCi/l in the Floridan. Potential sources include shallow phosphate sediments and monazite sands and possibly crystalline basement rocks or other strata unrelated to phosphatic zones of current economic interest. The existing radium-226 data base is rather marginal in terms of number and spatial distribution of analyses, particularly for the water table and Upper Floridan aquifer. Existing radium data do not substantiate widespread contamination of ground water as a result of the phosphate industry. However, local contamination associated with specific operations has occurred.  相似文献   

12.
This study evaluates the importance of geologic and geographic factors in constraining the location of limestone mining operations for the production of cement in the Great Lakes region of the United States. Cities and their infrastructure require abundant cement, which is manufactured from limestone and other quarry products, but expansion of cities limits the locations of these operations. Possible locations of limestone and cement operations are controlled by geologic factors including distribution and mineralogy of geologic formations as well as depth of overburden, and geographic factors including location of wetlands, cities, and other surface features that preclude development of quarries and manufacturing operations. Overlay analysis was used to evaluate the importance of these factors. Results show that, although limestone underlies about a third of the region, almost 50 percent of this limestone is unavailable for quarrying due to coverage by the built environment, protected natural areas, or excessive overburden thickness. When characteristics such as limestone quality are also accounted for, accessible resources shrink to as little as 2 percent of the total land area. Although the remaining 2 percent of land area may supply local needs for some years, geologic factors clearly must be included in long-term regional land use planning.  相似文献   

13.
Phosphate rocks, used for phosphorus (P) fertilizer production, are a non-renewable resource at the human time scale. Their depletion at the global scale may threaten global food and feed security. To prevent this depletion, improved P resource recycling from food chain waste to agricultural soils and to the food and feed industry is often presented as a serious option. However, waste streams are often complex and their recycling efficiency is poorly characterized. The aim of this paper is to estimate the P recovery and recycling potential from waste, considering France as a case study. We assessed the P flows in food processing waste, household wastewater and municipal waste at the country scale using a substance flow analysis for the year 2006. We also quantified the P recycling efficiency as the fraction of P in waste that ultimately reached agricultural soils or was recycled in the food and feed industry. Efforts were made to limit data uncertainty by cross-checking multiple data sources concerning P content in waste materials. Results showed that, in general, P recovery in waste was high but that the overall P recycling efficiency was only 51% at the country scale. In particular, P recycling efficiency was 75% for industrial waste, 43% for household wastewater and 47% for municipal waste. The remaining P was discharged into water bodies or landfilled, causing P-induced environmental problems as well as losses of nutrient resources. Major P losses were through food waste (which amounted to 39% of P in available food) and treated wastewater, and the findings were confirmed through cross-checking with alternative data sources. Options for improving P resource recycling and, thereby, reducing P fertilizer use were quantified but appeared to be less promising than scenarios based on reduced food waste or redesigned agricultural systems.  相似文献   

14.
At first ‘sustainable mining’ could be perceived as a paradox—minerals are widely held to be finite resources with rising consumption causing pressure on known resources. The true sustainability of mineral resources, however, is a much more complex picture and involves exploration, technology, economics, social and environmental issues, and advancing scientific knowledge—predicting future sustainability is therefore not a simple task. This paper presents the results from a landmark study on historical trends in Australian mining, including ore milled, ore grades, open cut versus underground mining, overburden/waste rock and economic resources. When complete data sets are compiled for specific metals, particular issues stand out with respect to sustainability—technological breakthroughs (e.g. flotation, carbon-in-pulp), new discoveries (e.g. uranium or U), price changes (e.g. Au, boom/bust cycles), social issues (e.g. strikes), etc. All of these issues are of prime importance in moving towards a semi-quantitative sustainability model of mineral resources and the mining industry. For the future, critical issues will continue to be declining ore grades (also ore quality and impurities), increased waste rock and associated liabilities, known economic resources, potential breakthrough technologies, and broader environmental constraints (e.g. carbon costs, water). For this latter area, many companies now report annually on sustainability performance—facilitating analysis of environmental sustainability with respect to production performance. By linking these two commonly disparate aspects—mining production and environmental/sustainability data—it becomes possible to better understand environmental sustainability and predict future constraints such as water requirements, greenhouse emissions, energy and reagent inputs, and the like. This paper will therefore present a range of fundamental data and issues which help towards quantifying the resource and environmental sustainability of mining—with critical implications for the mining industry and society as a whole.  相似文献   

15.
In this study, we analyze the evolution of Canada's mining industry from 1929 to 2006, focussing on the determinants of the number of firms in the industry and why this number changed over that period. Most empirical studies of industry evolution have focused on manufacturing industries that share similar structural characteristics. Perhaps because of this, extant models of industry evolution tend to ignore industry-specific and national-specific factors that can cause atypical trajectories, that is, heterogeneous industry evolution. Initial inspection of the Canadian mining industry shows that it is atypical in that it exhibits “negative skew” over time in the number of firms rather than the typical “positive skew.” We review two dominant theoretical approaches to industry evolution: the density-dependence theory and variants of industrial organization economics. We also consider possible sources of industry evolution heterogeneity, focussing particularly on “regulatory punctuation”. Using Canadian mining data, we find that the traditional models do not fully explain the changes in population size in Canada's mining industry. As a result, we introduce a number of hybrid models. The results from these hybrid models suggest that Canadian-specific regulatory punctuations, particularly the introduction of significant new taxes, environmental legislation, and incentives have shaped the trajectory of mining firm participation.  相似文献   

16.
Rising demand for shrimp in the developed nations has helped to foster a dramatic growth in marine shrimp aquaculture, particularly in South America and South Asia. In Thailand, Marine shrimp aquaculture is now an important earmer of foreign exchange. The growth in Production has been achieved through the expansion of the culture area and the adoption of intensive production methods. The conversion of near-shore areas to shrimp culture, however, is proving to have many consequences that impinge on the environmental integrity of coastal areas. This paper reviews the development of Thailand's marine shrimp culture industry and examines the nature of the environmental impacts that are emerging. It then discusses the implications these have for rural poor and the long-term viability of the culture industry.  相似文献   

17.
Across the Americas, biofuels production systems are diverse due to geographic conditions, historical patterns of land tenure, different land use patterns, government policy frameworks, and relations between the national state and civil society, all of which shape the role that biofuels play in individual nations. Although many national governments throughout the Americas continue to incentivize growth of the biofuels industry, one key challenge for biofuels sustainability has been concern about its social impacts. In this article, we discuss some of the key social issues and tensions related to the recent expansion of biofuels production in Mexico, Colombia, and Brazil. We argue that a process of “simplification” of ecological and cultural diversity has aided the expansion of the biofuels frontier in these countries, but is also undermining their viability. We consider the ability of governments and non-state actors in multi-stakeholder initiatives (MSI) to address social and environmental concerns that affect rural livelihoods as a result of biofuels expansion. We analyze the tensions between global sustainability standards, national level policies for biofuels development, and local level impacts and visions of sustainability. We find that both government and MSI efforts to address sustainability concerns have limited impact, and recommend greater incorporation of local needs and expertise to improve governance.  相似文献   

18.
The Bureau of Mines investigated the resources, costs, capacities, market relationships, and short- and long-run supply of phosphate rock and phosphoric acid. The 206 mines and deposits evaluated in 30 market economy countries (MECs) contain an estimated 35.1 billion tonnes of recoverable phosphate rock (demonstrated resource level). US resources are sufficient to satisfy both the domestic market and an export market for phosphate products well beyond 2000. Resource depletion at current producers, however, means new property development (with higher costs) will be required if US production levels are to be maintained. Existing worldwide capacity can satisfy expected demand through the early 1990s. Expansion at existing mines or low demand growth could mean no new property development is required before the late 1990s. Worldwide, almost $8 billion could be required for the development of new phosphate rock properties between now and 2000, given 3% annual growth in demand. Though profit may not be the principal motivation for development of government-owned operations, most properties that could develop in the 1990s would require price increases of 20–50% to break even. To earn a 15% rate of return on investment, prices must rise to nearly double the $23–271 tonne US price level of 1988. Current US phosphate rock and phosphoric acid producers appear to be competitive (on a variable cost basis) with many other suppliers in major markets. New US properties will have higher variable costs than current producers; however, they are competitive with most projected new foreign development. The US phosphoric acid industry will most likely face increased competition as more of the foreign phosphate rock producers develop the capacity to process rock into phosphoric acid and other fertilizer products.  相似文献   

19.
Phosphate and micronutrient fertilizers contain potentially harmful trace elements, such as arsenic (As), cadmium (Cd), and lead (Pb). We investigated if application of these fertilizer increases the As, Cd, and Pb concentrations of the receiving soils. More than 1000 soil samples were collected in seven major vegetable production regions across California. Benchmark soils (no or low fertilizer input) sampled in 1967 and re-sampled in 2001 served as a baseline. Soils were analyzed for total concentrations of As, Cd, Pb, P, and Zn. The P and Zn concentrations of the soils were indicators of P fertilizer and micronutrient inputs, respectively. Results showed that the concentrations of these elements in the vegetable production fields in some production areas of California had been shifted upward. Principal component analysis and cluster analysis showed that the seven production areas could be sorted into three categories: (i) enrichment of As, Cd, and Pb, which was associated with the enrichment of P and Zn in one of the seven areas surveyed; (ii) enrichment of As, which was associated with enrichment of Zn in two of the seven areas surveyed; and (iii) no remarkable correlation between enrichment of As, Cd, and Pb and enrichment of P and Zn in the other four areas surveyed.  相似文献   

20.
Over the last two decades, mining and mineral exploration companies have adopted various environmental management practices in response to society’s pressure for better environmental protection. The literature highlights a number of benefits and challenges for companies adopting environmental management practices with the Greek Mining and Mineral Industry (GMMI) facing similar issues. In order to analyze the challenges faced by the GMMI, a Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis was conducted, which examined the strengths, weaknesses, opportunities and threats faced by the industry when adopting environmental management practices. The analysis prescribes policy recommendations both for the government and industry which, if adopted, could facilitate improved environmental performance.  相似文献   

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