Hydrocarbon exploration and production in sub-Saharan Africa

In 1988, sub-Saharan Africa provided only 2.3 million bbllday of oil and 4 thousand million m³ of natural gas, representing respectively, approximately 4% and less than 1% of the world's supplies of those energy sources. This is surprising, given the extensive land area and the presence of sedimentary basins in many of the countries of the region. This paper explores the reasons for this relatively low production, details exploration efforts to date and makes recommendations for increasing investment in petroleum exploration in sub-Saharan Africa.     

The Worldwide Availability of Fluorspar

This paper reviews a recent assessment of fluorspar reserves and resources for 13 market economy countries and the People's Republic of China, and how they relate to the overall availability of fluorspar on the world market. Current world production, consumption and world trade issues are discussed.
Nearly 5 million tonnes of fluorspar were produced in 1985, and approximately 60% of that enters the world export market. In recent years world trade has started to shift away from the acid, metallurgical and ceramic grades of fluorspar, as ore-producing countries look towards higher-value downstream products.
Total potentially recoverable fluorspar from 52 major producing mines and deposits is estimated at nearly 95 million tonnes (as of January 1985). The Republic of South Africa accounts for 31% of the reserves, with Mexico and the People's Republic of China each contributing 18%.
The average total cost and availability of fluorspar is evaluated. Approximately 75% of acid-grade fluorspar evaluated is potentially available at or below a 1985 constant-dollar cost of US$110 tonne⁻¹. Nearly 94% of metallurgical grades are potentially available at costs of US$75 tonne⁻¹ and below, and virtually all of the ceramic grades could be produced at costs below the 1985 reported market price of US$103 tonne⁻¹.     

Libya's Great Manmade River Project

When completed, Libya's Great Manmade River Project will transport through a system of pipelines 12–14 million m³ of water per day from the southern region of the country to the northern coastal areas. The system will provide water for municipal, industrial and agricultural users. This paper describes the project, the uses to which its water will be put and the institutional issues which need to be addressed when the Great Manmade River Project delivers vast quantities of water to the coastal areas. The biggest problem for Libya could be finding and training the vast numbers of technical people needed to manage and operate the system.     

Potential Economic Impacts of Environmental Flows Following a Possible Listing of Endangered Texas Freshwater Mussels

Texas water resources, already taxed by drought and population growth, could be further stressed by possible listings of endangered aquatic species. This study estimated potential economic impacts of environmental flows (EFs) for five freshwater unionid mussels in three Central Texas basins (Brazos, Colorado, and Guadalupe‐San Antonio Rivers) that encompass 36% of Texas (~246,000 km²). A water availability model projected reductions in water supply to power, commercial and industrial, municipal, and agriculture sectors in response to possible EFs for mussels. Single‐year economic impacts were calculated using publicly available data with and without water transfers. Benefits of EFs should also be assessed, should critical habitat be proposed. Potential economic losses were highest during droughts, but were nominal (<$1 M) in wetter years — even with high EFs. Reduced supplies to San Antonio area power plants caused worst‐case impacts of a single‐year shutdown up to $107 million (M) during drought with high EFs. For other sectors in the study area, water transfers reduced worst‐case losses from $80 to $11 M per year. Implementing innovative water management strategies such as water markets, conjunctive use of surface water and groundwater, aquifer storage and recovery could mitigate economic impacts if mussels — or other widely distributed aquatic species — were listed. However, approaches for defining EFs and strategies for mitigating economic impacts of EFs are needed.     

Life cycle analysis of silane recycling in amorphous silicon-based solar photovoltaic manufacturing

Amorphous silicon (a-Si:H)-based solar cells have the lowest ecological impact of photovoltaic (PV) materials. In order to continue to improve the environmental performance of PV manufacturing using proposed industrial symbiosis techniques, this paper performs a life cycle analysis (LCA) on both conventional 1-GW scaled a-Si:H-based single junction and a-Si:H/microcrystalline-Si:H tandem cell solar PV manufacturing plants and such plants coupled to silane recycling plants. Both the energy consumed and greenhouse gas emissions are tracked in the LCA, then silane gas is reused in the manufacturing process rather than standard waste combustion. Using a recycling process that results in a silane loss of only 17% instead of conventional processing that loses 85% silane, results in an energy savings of 81,700 GJ and prevents 4400 tons of CO₂ from being released into the atmosphere per year for the single junction plant. Due to the increased use of silane for the relatively thick microcrystalline-Si:H layers in the tandem junction plants, the savings are even more substantial – 290,000 GJ of energy savings and 15.6 million kg of CO₂ eq. emission reductions per year. This recycling process reduces the cost of raw silane by 68%, or approximately $22.6 million per year for a 1-GW a-Si:H-based PV production facility and over $79 million per year for tandem manufacturing. The results are discussed and conclusions are drawn about the technical feasibility and environmental benefits of silane recycling in an eco-industrial park centered around a-Si:H-based PV manufacturing plants.     

VISITOR VALUES AND LOCAL ECONOMIC IMPACTS OF RIPARIAN HABITAT PRESERVATION: CALIFORNIA'S KERN RIVER PRESERVE1

ABSTRACT: Preservation of the few remaining ecologically vital riparian areas in the southwestern United States is a significant policy concern. This article reports on two economic aspects of preserving a nationally renowned riparian birding area in Southern California. First, the article examines visitor willingness to pay (WTP) for habitat restoration and estimates an annual WTP of US $77 per visitor to preserve the habitat, about a half‐million dollars a year for estimated visitor numbers in 2000 and 2001. Second, it documents visitor expenditures in the local economy to be approximately three‐quarters of a million dollars per year. This direct visitor spending attributable to the riparian habitat generates around US $1.3 million in increased local business activity in this relatively remote rural area.     

The Worldwide Availability of Gold

This paper summarizes Bureau of Mines research relating to the state of the world gold industry. The authors discuss the world gold industry structure, demonstrated gold resources, current production, and the long-term cost and availability of potential future gold production.
The long-term cost and availability of primary gold production from 111 significant producing mines and developing deposits in 13 market economy countries (MECs) is evaluated. Total recoverable gold available (as of January 1984) from the evaluated mines and deposits is estimated at 819 million troy ounces. The Republic of South Africa is estimated to account for 87% of total recoverable gold. The USA and Canada account for 4% and 4.5% of the total, respectively. Eighty-three per cent of total recoverable gold is available at a constant 1984 break-even price of $400 per ounce, and 70% is available at $300 per ounce. South Africa accounts for 90% of the gold available at $400 per ounce or less. Gold resources in the Soviet Union and China are discussed but not evaluated for costs of production. Some conclusions of the analyses are that South Africa should remain the largest world producer until the year 2000 and annual MEC output in the year 2000 should not be significantly different from current output, given constant 1984 gold prices of more than $300 per ounce.     

Mineral potential and scope of investment in the Republic of Yemen

On 22 May 1990 the Yemen Arab Republic and Peoples Democratic Republic of Yemen were unified to form the Republic of Yemen, with a population of about 14 million people in an area of about 580 000 km². The Republic of Yemen is hoping to develop its mineral industry. Possessing a well established geological database plus a newly issued mining law and investment law, Yemen is inviting all investors, whether from the Yemeni private sector or foreign companies, either solely or in joint ventures to investigate opportunities in minerals and construction and industrial materials.     

Multiple scales of diamond mining in Akwatia,Ghana: addressing environmental and human development impact

Ghana is the second largest producer of gold in sub-Saharan Africa, and has experienced a significant increase in national mining production over the last two decades. Between 1983 and 1998, the mining industry brought approximately US $4 billion in foreign direct investment to Ghana. While large-scale gold mining has seen a significant increase, artisanal gold and diamond mining product have grown exponentially. While much research has been conducted on gold mining in Ghana, there is relatively little research on the environmental and human development consequences of diamond mining in the country. Unlike other West African countries such as Sierra Leonne and Liberia, small-scale diamond mining in Ghana has not been linked to conflict but its role in development has also been relatively modest. This paper examines large and small-scale mining in Ghana's largest diamond mining town, Akwatia, and their relative impact on environmental degradation, health, and the livelihood of artisanal miners. We conclude that while an increase in artisanal diamond mining has been a means of employement and income-generation for small-scale miners, there are some human development challenges, related to environmental burden from land degradation and health. GCD is an ailing mining company in Ghana, in desperate need of an injection of capital to keep the mine alive, but botched bidding has slowed the process of de-regulating the company. We also conclude that the de-regulation of GCD may lead to a relatively reduced environmental burden in Akwatia and more revenue for the GCD to invest in the human development needs of communities in the town.     

Challenges to measuring,monitoring, and addressing the cumulative impacts of artisanal and small-scale gold mining in Ecuador

Portovelo-Zaruma, Ecuador is an artisanal and small-scale gold mining (ASGM) region with approximately 6000 gold miners working with mercury and cyanide. Although artisanal gold mining (AGM) has taken place in Portovelo-Zaruma for centuries, highly mechanized small-scale gold mining (SGM) processing plants capable of increased throughput began being built in the 1990s. While there are benefits associated with ASGM, there are also negative impacts experienced by the miners and the surrounding communities. To take advantage of ASGM as a poverty-alleviating mechanism while reducing unwanted externalities, the cumulative impacts must be understood. Numerous challenges to measuring, monitoring, and addressing ASGM impacts result from the complexity of the impacts themselves, the nature of the gold mining as an informal industry, and the shortfalls in the current regulatory framework. These are discussed in the context of ongoing, unresolved issues including efforts to address trans-boundary water pollution, management of mining waste, and conflicts regarding priorities, ambiguities, and enforcement of existing regulations and policies. Internationally, interventions to address both AGM and SGM impacts have typically focused almost exclusively on technological changes through the elimination of mercury use. Our analysis suggests that to better address ASGM and their cumulative impacts in Ecuador, it will be beneficial to revisit the legal definitions of AGM and SGM. Additionally, promotion of information-based strategies including educational outreach programs and cross-scale and cross-level mitigation methods may also be beneficial. The success of these strategies to reduce ASGM-related cumulative impacts will depend on sufficient funding and the commitment of stakeholders.     

Resident Motivations and Willingness-to-Pay for Urban Biodiversity Conservation in Guangzhou (China)

The monetary assessment of biodiversity measures the welfare damages brought by biodiversity losses and the cost-benefit analysis of conservation projects in a socio-economic context. The contingent valuation method could include motivational factors to strengthen economic analysis of nature conservation. This study analyzed Guangzhou residents’ motivations and willingness-to-pay (WTP) for an urban biodiversity conservation program in the National Baiyun Mountain Scenic Area (BMSA). The peri-urban natural site, offering refuge to some endemic species, is under increasing development pressures for recreational and residential use. A questionnaire survey was conducted in the Guangzhou metropolitan area during June to October 2007. We interviewed face-to-face 720 stratified sampled households to probe residents’ attitudes towards the city’s environmental issues, motivations for urban nature conservation, and WTP for biodiversity conservation. Principal component analysis identified five motivational factors, including environmental benefit, ecological diversity, nature-culture interaction, landscape-recreation function, and intergenerational sustainability, which illustrated the general economic values of urban nature. Logistic regression was applied to predict the probability of people being willing to pay for the urban biodiversity conservation in BMSA. The significant predictors of WTP included household income and the factor nature-culture interaction. The median WTP estimated RMB149/household (about US$19.5/household) per year and an aggregate of RMB291 million (approximately US$19.5/household) per year and an aggregate of RMB291 million (approximately US38.2 million) annually to support the urban conservation project. Including public motivations into contingent valuation presents a promising approach to conduct cost-benefit analysis of public projects in China.     

Simulating Direct and Indirect Damages to Commercial Fisheries from Marine Sand Mining: A Case Study in Korea

Rapid growth in marine sand mining for construction and other uses poses environmental challenges to coastal nations virtually worldwide. Yet the development of management policies, such as a system of fees imposed on operators for damage caused by mining, has been frustrated by a lack of studies to support such measures. Adapting a Beverton-Holt bioeconomic model, this paper attempts to contribute to the estimation of external costs to commercial fisheries due to marine mining. Using the major mining area of Ongjin in Korea as a case study, we estimate economic losses in use value of commercial fisheries through the time to recovery of the injured resource stocks. Present value of lost catch over a 1-year period from mining to resource recovery is estimated at $38,851 for a single “prototype” mining site. Estimated cumulative damages due to recurring mining for 5 and 10 years are $1.5 million and $2.2 million, respectively, at 20 mining sites. Sensitivity analyses are used to examine the effects of alternative assumptions to assess the many sources of uncertainty. Using a form of meta-analysis, dose-response information is used to assess the excess mortality the mining sediment plume has on eggs and larvae and, ultimately, on the value of lost catch ($841). Also addressed is the importance of specifying the appropriate “premining” conditions against which to assess environmental losses at the mining site. Damages estimated with premining fish populations are $23,066 higher than is the case using postmining conditions. Overall, the illustrative results suggest the variety of complex conditions which influence damage to fisheries from mining and which can benefit from further study to improve management guidelines. An erratum to this article can be found at     

ECONOMIC IMPACTS OF GUIDED WHITEWATER RAFTING: A STUDY OF FIVE RIVERS1

ABSTRACT: This paper presents estimates of the statewide economic impacts of guided whitewater rafting on five rivers in six states: the Nantahala (North Carolina), Gauley (West Virginia), Kennebec (Maine), Middle Fork of the Salmon (Idaho), and Chattooga (Georgia-South Carolina). Except for the Chattooga and Middle Fork, rafting is dependent on upstream dam releases. Guide fees range from about $15 per trip on the Nantahala to over $1,000 on the Middle Fork. Economic impacts per nonresident 1000 visitors increase along with length of the rafting trip and remoteness of the river. Total industrial output per 1000 nonresident visitors ranged from $95,000 on the Nantahala to over $2.5 million on the Middle Fork. However, because of differences in annual visitation levels, total impacts were greatest at the Nantahala, at over $14 million in 1993. Multipliers for all economic measures were relatively consistent over the rivers. Employment multipliers (Type III) ranged from 1.67 to 1.90, income multipliers from 2.0 to 2.4, and industrial output multipliers from 2.1 to 2.5.     

Global trends in gold mining: Towards quantifying environmental and resource sustainability

In recent years, due to public concern over perceived and actual environmental impacts, the global mining industry has been moving towards a more sustainable framework. For gold mining, there are a number of fundamental issues with regard to assessing sustainability. Commonly perceived as a finite and non-renewable resource, long-term gold production trends include declining ore grades and increasing solid wastes (tailings, waste rock) and open cut mining. Conversely, core sustainability issues include water, energy and chemical consumption and pollutant emissions—also known as ‘resource intensity’. It is important to recognise the links between gold production trends and resource intensity, as this is critical for understanding future sustainability challenges. This paper links data sets on historic gold mining production trends with emerging sustainability reporting to estimate resource intensity, demonstrating the sensitivity of ore grade for gold production and sustainability. Final judgement of the sustainability of gold mining must take account of the sensitivity of the ore grade in the resource intensity of gold production. This has implications for environmental policy and sustainability reporting in the gold mining sector.     

The Amazon between economy and ecology

The soils of the Amazon's rainforests, unlike soils in rainforests in other parts of the world, have very low productivity. Experiments have shown that the Amazon's timber productivity of 2–3 m³ per year per hectare is considerably below that achievable in Northern Europe. Sustainable agricultural development therefore can be expected to be very low. However, the mineral resources of the Amazon are very extensive and offer a way to develop the Amazon without destroying the ecology, provided that some limits are set on non-mining activities.     

Evaluating the PM damage cost due to urban air pollution and vehicle emissions in Seoul, Korea

This study evaluated the prospective damage costs of PM(2.5) inhalation. We performed a health risk assessment based on an exposure-response function to estimate the annual population risk in the Seoul metropolitan city, Korea. Also, we estimated a willingness-to-pay (WTP) amount for reducing the mortality rate in order to evaluate a statistical life value. We combined the annual population risk and the value-of-statistical-life to calculate the damage cost estimate. In the health risk assessment, we applied the PM(2.5) relative risk to evaluate the annual population risk. We targeted an exposure population of 5,401,369 persons who were over the age of 30. Using a Monte-Carlo simulation for uncertainty analysis, we estimated that the population risk of PM(2.5) inhalation during a year in Seoul is 2181 premature deaths for acute exposure and 18,510 premature deaths for chronic exposure. The monthly average WTP for 5/1000 mortality reduction over ten years is $20.20 USD (95% C.I: $16.60-24.50) and the implied value-of-statistical-life (VSL) is $485,000 USD (95% C.I: $398,000-588,000). The damage cost estimate due to risk from PM(2.5) inhalation in Seoul is about $1057 million USD per year for acute exposure, and $8972 million USD per year for chronic exposure. It is important to note that this cost estimate does not reflect all health damage cost estimates in this urban area. This recommendation is a model for evaluating a mortality risk reduction and as such we must re-evaluate an integrated application of morbidity risk.     

Toxic mercury versus appropriate technology: Artisanal gold miners’ retort aversion

Mercury-usage in artisanal and small-scale gold mining (ASGM) has accelerated in developing countries during the last thirty years resulting in negative environmental and health impacts. As awareness of mercury contamination from ASGM has grown, a number of strategic initiatives have been introduced to reduce the impact of the toxic substance. The adoption of the retort, a device capable of recycling up to 95 per cent of mercury in gold extraction, constitutes a broadly recognized approach. Based on case-study research in Tanzania, this paper examines an ASGM area, which has been targeted by several mercury-reducing efforts. Based on survey data, key informants interviews, and visitor observations, the paper examines the impact of these efforts on mining techniques and residents’ attitudes towards the use of mercury. Despite the seemingly obvious advantages from adopting retorts or other mercury-reducing techniques – economic, environmental, and health-wise – miners continue to use mercury haphazardly, while demonstrating an only limited awareness of the toxicity of the substance. The paper discusses the possible explanations behind this as well as possible ways forward in facilitating the reduction of mercury in ASGM operations.     

EFFECTS OF CROPPING SYSTEMS ON NO3-N LOSSES TO TILE DRAIN1

Abstract: Diverse cropping systems can have significant impacts on nutrient losses through tile drain systems and to surface water bodies (rivers and streams). Increased transport of nitrogen to water bodies can reduce dissolved oxygen and enrich the supply of nutrients, resulting in hypoxic zones. With the objective of reducing the transport of nutrients from agricultural watersheds, long term studies (1990 to 1998) were conducted in Iowa to investigate the impact of tillage, crop rotation, and N-management practices on NO₃-N leaching losses to tile drain water. Results of these studies indicated that continuous corn production systems required higher input of nitrogen fertilizers and resulted in significantly higher NO₃-N leaching losses compared to rotated corn in plots either fertilized with manure or urea ammonium nitrate. Also, rotated corn gave higher corn yields, 8 megagrams per hectare (Mg/ha) versus 6 Mg/ha, than continuous corn. The higher N application rates resulted in increased NO₃-N concentrations in tile water. A strip cropping system with alfalfa lowered NO₃-N concentrations in tile water to less than 10 mg/l. These studies indicated that better land use practices can reduce NO₃-N leaching losses to surface and ground water systems and will help in mitigating environmental concerns of the production agriculture.     

Assessing the economic impact of invasive species: the case of yellow starthistle (Centaurea solsitialis L.) in the rangelands of Idaho, USA

Yellow starthistle (Centaurea solsitialis L.) is an invasive weed that creates problems for the management of Idaho's rangelands. A bioeconomic approach combined with an input-output economic model is used to estimate direct and secondary economic costs of the weed in relation to its interference with agricultural and non-agricultural benefits that rangelands provide. Direct economic costs of the infestations were estimated to be of 8.2 million '05 dollars per year, and secondary costs of 4.5 million '05 dollars per year, for a total of 12.7 million '05 dollars; agricultural related economic impacts accounted for 79% of this total cost, and non-agricultural for 21%.     

Cost/Benefit Considerations for Recent Saltcedar Control,Middle Pecos River,New Mexico

Major benefits were weighed against major costs associated with recent saltcedar control efforts along the Middle Pecos River, New Mexico. The area of study was restricted to both sides of the channel and excluded tributaries along the 370 km between Sumner and Brantley dams. Direct costs (helicopter spraying, dead tree removal, and revegetation) within the study area were estimated to be $2.2 million but possibly rising to $6.4 million with the adoption of an aggressive revegetation program. Indirect costs associated with increased potential for erosion and reservoir sedimentation would raise the costs due to increased evaporation from more extensive shallows in the Pecos River as it enters Brantley Reservoir. Actions such as dredging are unlikely given the conservative amount of sediment calculated (about 1% of the reservoir pool). The potential for water salvage was identified as the only tangible benefit likely to be realized under the current control strategy. Estimates of evapotranspiration (ET) using Landsat TM data allowed estimation of potential water salvage as the difference in ET before and after treatment, an amount totaling 7.41 million m³ (6010 acre-ft) per year. Previous saltcedar control efforts of roughly the same magnitude found that salvaged ET recharged groundwater and no additional flows were realized within the river. Thus, the value of this recharge is probably less than the lowest value quoted for actual in-channel flow, and estimated to be < $63,000 per year. Though couched in terms of costs and benefits, this paper is focused on what can be considered the key trade-off under a complete eradication strategy: water salvage vs. erosion and sedimentation. It differs from previous efforts by focusing on evaluating the impacts of actual control efforts within a specific system. Total costs (direct plus potential indirect) far outweighed benefits in this simple comparison and are expected to be ongoing. Problems induced by saltcedar control may permanently reduce reservoir capacity and increase reservoir evaporation rates, which could further deplete supplies on this water short system. These potential negative consequences highlight that such costs and benefits need to be considered before initiating extensive saltcedar control programs on river systems of the western United States.