Cover Image
close this bookConducting Environmental Impact Assessment in Developing Countries (United Nations University, 1999, 375 p.)
View the document(introduction...)
View the documentPreface
View the documentAbbreviations
close this folder1. Introduction
View the document1.1 The environmental movement
View the document1.2 Tracing the history of environmental impact assessment
close this folder1.3 Changes in the perception of EIA
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View the document1.3.1 EIA at the project level
View the document1.3.2 From project level to regional EIA
View the document1.3.3 Policy level strategic EIA
View the documentFURTHER READING
close this folder2. Introduction to EIA
View the document2.1 What is EIA?
View the document2.2 Who is involved in the EIA process?
View the document2.3 When should the EIA be undertaken?
close this folder2.4 Effectiveness of EIA
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View the document2.4.1 Legal regulations
View the document2.4.2 Rational and open decision-making
View the document2.4.3 Project EIA sustained by strategic EIA
View the document2.4.4 Room for public participation
View the document2.4.5 Independent review and central information
View the document2.4.6 Scoping in EIA
View the document2.4.7 Quality of the EIA
View the document2.5 EIA and other environmental management tools
close this folder3. EIA process
View the document3.1 Introduction
close this folder3.2 Principles in managing EIA
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View the document3.2.1 Principle 1: Focus on the main issues
View the document3.2.2 Principle 2: Involve the appropriate persons and groups
View the document3.2.3 Principle 3: Link information to decisions about the project
View the document3.2.4 Principle 4: Present clear options for the mitigation of impacts and for sound environmental management
View the document3.2.5 Principle 5: Provide information in a form useful to the decision makers
View the document3.3 Framework of environmental impacts
close this folder3.4 EIA process in tiers
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close this folder3.4.1 Screening
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View the document3.4.1.1 Illustrations of screening
View the document3.4.2 Scoping
View the document3.4.3 The initial environmental examination
close this folder3.4.4 The detailed EIA study
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View the document3.4.4.1 Prediction
View the document3.4.4.2 Assessment
View the document3.4.4.3 Mitigation
View the document3.4.4.4 Evaluation
View the document3.5 Resources needed for an EIA
close this folder3.6 Some illustrations of EIA processes in various countries
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close this folder3.6.1 EIA system in Indonesia
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View the document3.6.1.1 Responsibility for AMDAL
View the document3.6.1.2 Screening: determining which projects require AMDAL
View the document3.6.1.3 AMDAL procedures
View the document3.6.1.4 Permits and licenses
View the document3.6.1.5 Public participation in AMDAL
close this folder3.6.2 EIA procedure and requirements in Malaysia
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View the document3.6.2.1 Integrated project-planning concept
View the document3.6.2.2 How is EIA processed and approved?
close this folder3.6.3 EIA in Canada
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View the document3.6.3.1 The process
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close this folder4. EIA methods
View the document4.1 Introduction
View the document4.2 Checklists
close this folder4.2.1 Descriptive checklists
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View the document4.2.2 Weighted-scale checklists
View the document4.2.3 Advantages of the checklist method
View the document4.2.4 Limitations of the checklist method
close this folder4.3 Matrix
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View the document4.3.1 Descriptive matrix
View the document4.3.2 Symbolized matrix
close this folder4.3.3 Numeric and scaled matrices
View the document4.3.3.1 Simple numeric matrix
View the document4.3.3.2 Scaled matrices
View the document4.3.4 The component interaction matrix
View the document4.3.5 Advantages of the matrix approach
View the document4.3.6 Limitations of the matrix approach
close this folder4.4 Networks
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View the document4.4.1 Advantages of the network method
View the document4.4.2 Limitations of the network method
View the document4.5 Overlays
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close this folder5. EIA tools
close this folder5.1 Impact prediction
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View the document5.1.1 Application of methods to different levels of prediction
close this folder5.1.2 Informal modelling
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View the document5.1.2.1 Approaches to informal modelling
View the document5.1.3 Physical models
View the document5.1.4 Mathematical models
View the document5.1.5 Modelling procedure
View the document5.1.6 Sensitivity analysis
View the document5.1.7 Probabilistic modelling
View the document5.1.8 Points to be considered when selecting a prediction model
View the document5.1.9 Difficulties in prediction
close this folder5.1.10 Auditing of EIAs
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View the document5.1.10.1 Auditing prediction in EIAs
View the document5.1.10.2 Problems in conducting predictive techniques audit
View the document5.1.11 Precision in prediction and decision resolution
close this folder5.2 Geographical information system
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View the document5.2.1 Data overlay and analysis
View the document5.2.2 Site impact prediction
View the document5.2.3 Wider area impact prediction
View the document5.2.4 Corridor analysis
View the document5.2.5 Cumulative effects assessment and EA audits
View the document5.2.6 Trend analysis
View the document5.2.7 Predicting impacts in a real time environment
View the document5.2.8 Continuous updating
View the document5.2.9 Multi attribute tradeoff system (MATS)
View the document5.2.10 Habitat analysis
View the document5.2.11 Aesthetic analysis
View the document5.2.12 Public consultation
View the document5.2.13 Advantages of the GIS method
View the document5.2.14 Limitations of the GIS method
close this folder5.3 Expert systems for EIA
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View the document5.3.1 Artificial intelligence and expert systems
View the document5.3.2 Basic concepts behind expert systems
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close this folder6. Environmental management measures and monitoring
View the document6.1 Introduction
close this folder6.2 Environmental management plan (EMP)
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close this folder6.2.1 Issues and mitigation measures
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View the document6.2.1.1 Project siting
View the document6.2.1.2 Plant construction and operation
close this folder6.2.2 Illustrations of guidelines for mitigation measures for specific projects
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View the document6.2.2.1 Fertilizer industry
View the document6.2.2.2 Oil and gas pipelines
View the document6.2.2.3 Water resource projects
View the document6.2.2.4 Infrastructure projects
View the document6.2.3 Development of a green belt as a mitigation measure
View the document6.3 Post-project monitoring, post-audit, and evaluation
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close this folder7. EIA communication
View the document7.1 Introduction
View the document7.2 What is expected from the user of EIA findings?
close this folder7.3 Communication to the public
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close this folder7.3.1 Factors that may result in effective public participation
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View the document7.3.1.1 Preplanning
View the document7.3.1.2 Policy of the executing agency
View the document7.3.1.3 Resources
View the document7.3.1.4 Target groups
View the document7.3.1.5 Effective communication
View the document7.3.1.6 Techniques
View the document7.3.1.7 Responsiveness
View the document7.3.2 Overview of the roles of the public
close this folder7.3.3 Public participation techniques
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View the document7.3.3.1 Media techniques
View the document7.3.3.2 Research techniques
View the document7.3.3.3 Political techniques
View the document7.3.3.4 Structured group techniques
View the document7.3.3.5 Large group meetings
View the document7.3.3.6 Bureaucratic decentralization
View the document7.3.3.7 Interveners
View the document7.3.4 Implementing public participation
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close this folder8. Writing and reviewing an EIA report
close this folder8.1 Writing an EIA report
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View the document8.1.1 Guidelines for preparing EIA reports
View the document8.1.2 Comparison of guidelines of suggested/required components of an EIA report
close this folder8.2 Review of an EIA report
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View the document8.2.1 Purpose of the review
View the document8.2.2 Information and expertise needed for review
View the document8.2.3 Strategy of the review
close this folder8.2.4 Approach
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View the document8.2.4.1 Independent analysis
View the document8.2.4.2 Predetermined evaluation criteria
View the document8.2.4.3 Ad hoc review
View the document8.2.5 Specific document review criteria
close this folder8.3 Preparing terms of reference for consultants or contractors
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View the document8.3.1 Checking out the consulting organization
View the document8.3.2 Strategy for formulating TOR
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close this folder9. Emerging developments in EIA
View the document9.1 Introduction
close this folder9.2 Cumulative effects assessment
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close this folder9.2.1 Concepts and principles relevant to CEA
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View the document9.2.1.1 Model of causality
View the document9.2.1.2 Input-process-output model
View the document9.2.1.3 Temporal and spatial accumulation
View the document9.2.1.4 Control factors
close this folder9.2.2 Conceptual framework
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View the document9.2.2.1 Sources of cumulative environmental change
View the document9.2.2.2 Pathways of cumulative environmental change
View the document9.2.2.3 Cumulative effects
View the document9.2.3 Conclusion
close this folder9.3 Sectoral environmental assessment
View the document(introduction...)
View the document9.3.1 Need for SEA
View the document9.3.2 Differences between project level EIA and SEA
View the document9.3.3 Methodologies for SEA
View the document9.3.4 Status of SEA
View the document9.3.5 Effectiveness of SEA
close this folder9.4 Environmental risk assessments
View the document9.4.1 What is environmental risk assessment?
close this folder9.4.2 Terminology associated with ERA
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View the document9.4.2.1 Hazards and uncertainties
View the document9.4.3 ERA and the project cycle
View the document9.4.4 ERA builds upon EIA
View the document9.4.5 Basic approach to ERA
View the document9.4.6 Characterization of risk
View the document9.4.7 Risk comparison
View the document9.4.8 Quantitative risk assessments
View the document9.4.9 Risk communication
View the document9.4.10 Risk management
close this folder9.4.11 Guidelines for disaster management planning
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View the document9.4.11.1 Specification
View the document9.4.11.2 Plot plan
View the document9.4.11.3 Hazardous area classification
View the document9.4.11.4 P & I diagrams
View the document9.4.11.5 Storage of inflammable liquids
View the document9.4.11.6 Risk assessment
close this folder9.5 Environmental health impact assessment
View the document(introduction...)
View the document9.5.1 Need for EHIA
close this folder9.5.2 Potential methodologies and approaches for addressing health impacts
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View the document9.5.2.1 Adapt EIA study activities
View the document9.5.2.2 Integrate health impacts into EIA
View the document9.5.2.3 Use a targeted approach
View the document9.5.2.4 Probabilistic risk assessment
close this folder9.5.3 Proposed methodology
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View the document9.5.3.1 Determining the need for health impact assessment
View the document9.5.3.2 Identify health impacts
View the document9.5.3.3 Prediction of health impacts
View the document9.5.3.4 Interpreting health impacts
View the document9.5.3.5 Mitigation, monitoring, and reporting
close this folder9.6 Social impact assessment
View the document9.6.1 What is SIA? Why SIA?
View the document9.6.2 Identifying social impact assessment variables
View the document9.6.3 Combining social impact assessment variables, project/policy stage, and setting
close this folder9.6.4 Steps in the social impact assessment process
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View the document9.6.4.1 Public involvement
View the document9.6.4.2 Identification of alternatives
View the document9.6.4.3 Baseline conditions
View the document9.6.4.4 Scoping
View the document9.6.4.5 Projection of estimated effects
View the document9.6.4.6 Predicting response to impacts
View the document9.6.4.7 Indirect and cumulative impacts
View the document9.6.4.8 Change in alternatives
View the document9.6.4.9 Mitigation
View the document9.6.4.10 Monitoring
View the document9.6.5 Principles for SIA
View the document9.6.6 TOR for consultants
View the documentFURTHER READING
View the documentAnnex 9.1: Case study for risk assessments
close this folder10. Case studies to illustrate environmental impact assessment studies
View the documentCase study 10.1 Tongonan Geothermal Power Plant, Leyte, Philippines
View the documentCase study 10.2 Accelerated Mahaweli Development Programme
View the documentCase study 10.3 Tin Smelter Project in Thailand
View the documentCase study 10.4 Thai National Fertilizer Corporation Project
View the documentCase study 10.5 Map Ta Phut Port Project
View the documentCase study 10.6 EIA at Work: A Hydroelectric Project in Indonesia
View the documentCase study 10.7 The Greater Cairo Wastewater Project

Case study 10.3 Tin Smelter Project in Thailand

Notes: This case study can be used by trainees to make mitigation plans and discuss post-project monitoring.

Name of the project: Environmental impact assessment for tin smelter project.

Type of environmental analysis: EIA.

Type of project: This is a metal-refining industry. The manufacturing process essentially involves heating the ore and utilizing the difference in melting point temperature (alloy formation involves slightly different methods) for obtaining the separation of the various components including the production of the tin metal of over 99.9 per cent purity from the original ore concentrate of approximately 73-75 per cent purity.

This is the only tin-smelting and refining plant in Thailand. It is capable of producing about 40,000 Mt/year of refined tin, which is 20 per cent of current total world production. A number of by-products are also produced, including tin-lead.

The industry produces three types of waste: namely liquid, solid, and gas. Domestic wastewater, laboratory wastewater and plant surface run-off are the main liquid wastes. Heavy metals such as Fe, Pb, Ta, Nb, Ti, Sn, Al, Zi, and Cn are the main heavy metal pollutants. Solid waste management does not pose any significant problem. Some amounts of toxic heavy metals, including Pb, As, Sb, and Bi, are emitted to the atmosphere. Also the sulphur present mainly in the fuel can generate significant quantities of SOx. Thus air pollution is the most threatening hazard at a tin smelter.

Project location

The tin smelter is located at the southern promontory of Ao Kham Bay on the southeast shore of Phuket Island, which is about 6 km south of Phuket town though 12 km by road. The plant is located adjacent to the tin ore processing facility. The plant is bounded on the east and south by the sea and the west and southwest by coconut groves. The total area of the plant is 5.8 acres.

Reports on pertinent studies

See References 1-4, page 305.

Environmental study area

The study area includes the land mass within approximately a 5 km radius of the plant. This area has been determined to cover more than adequately any resources which may be significantly affected by the tin smelter operation.

EIA team

The EIA team consists of two co-managers, with one project field engineer, two air quality experts, one socio-economist, one water quality expert, and one ecologist, with support staff.

EIA budget adequacy

Adequate budget was provided.


The methodology for preparing the EIA is that recommended by NEB (Ref. 5, p. 305). It is based on the methodology developed by the Battelle Institute/United States Army Corps of Engineers. In this methodology environmental resources are classified and evaluated in four general headings, namely: (a) natural physical resources, (b) natural ecological resources, (c) human use of economic development resources, and (d) quality-of-life values. In addition to estimating effects of the tin smelter operations on these resources, and identifying, delineating, and quantifying adverse effects, the method includes preparation of recommendations for minimizing unavoidable adverse effects and for offsetting these by positive enhancement measures.

To supplement the data from different sources, a number of field surveys were made covering all specialized environmental impacts (including socio-economics, wildlife, flora, and fauna, plus a sampling analysis of wastewaters, drinking water quality, health status of the workers, etc).

Existing environmental conditions


Based on discussions with long-time residents of Phuket, it appears that prior to the construction of the tin smelter (about 20 years ago), the study area was sparsely populated, with land use including some coconut groves, rubber plantations, and secondary forest. Agricultural development coupled with population growth has resulted in increases in cultivated crops as well as coconut and rubber plantations and thus created a more densely populated agricultural zone.

Environmental concerns

During the past 20 years (the duration of tin smelter operations), several new families have moved into what was previously a sparsely inhabited area. This can be expected as a result of increased economic opportunities from the industrial development, improvements in transport/access, etc. It may also be expected that the increased population may result in increased frequency and opportunities for complaints. Complaints on record cover blasting noise and smoke.

Blasting noise from slag granulation: frequently 2-3 times/day, mostly occurring during night; continuous blasting noises (> 100 times in each duration); disturbs relaxation time of surrounding people, patients, children, and babies; and caused different levels of vibration to houses depending on distances - creating damage to items, e.g. mirrors, window panes, and roof tiles.

Smoke from blasting and stacks: aesthetic nuisance (clothes and houses got dirty, bad odours); and fear of illness due to bad odours.

Environmental base map

The environmental base map (EBM) shows the plant and its environs. The EBM shows all potentially sensitive environmental resources, that is any resource which might be significantly impaired by the plant operations, including waste emissions.

Environmental effects from project

Adverse effects on physical resources

Air quality: odour and dust nuisance during certain hours on some days (though the modelling and stack emissions indicate that the tin smelter may not be the source); reduced yields from fruits from coconut plantations; and visible damage to leaves.

Noise pollution: noise has affected most of the residents of the villages.

Adverse effects on water resources

The wastewaters discharged from the laboratory and canteen without any treatment are unsightly and these waters exceed Ministry of Industry (MOI) standards for some parameters.

Adverse effects on human use values: agriculture

The smelter air emissions have caused significant reductions in yields of coconut plantations. Also the toxic effects of groundwater and soil polluted by tin dredge tailings which have been panned or stored in the coconut groves by local villagers have caused the plants to yield less.

Adverse effects on quality-of-life values: socio-economics

About 90 per cent of the respondents at Ban Ao Makhan and 100 per cent at Ban Laem Phan Wa Wee were negatively affected by noise and dust emissions.

Positive effects on human use values

Water supply: the tin smelter operations created beneficial impacts on water supply in that the smelter made arrangements for local villagers to utilize the groundwater supply developed by the tin smelter.

Mining/mineral resources: the operation of the tin smelter has an obvious beneficial impact on local, regional, and national mineral resource development and subsequent beneficial economic impacts.

Quality-of-life values: wage earning forms the major proportion of household income in the area. The smelter has created job opportunities and other related employment opportunities for the local villagers. These indicate long-term benefits for the people in the area.

Land prices in the vicinity have increased because of the presence of the industry. Economic benefits include benefits of increased earning and creation of jobs for the workers and their families as well as the gross regional product, and overall economic benefit to the nation.

Summarized projected effects

The impacts of the smelter operations are both beneficial and adverse, with the beneficial impacts outweighing the adverse. The primary beneficial impact is the economic benefit which is believed to play a major role in the villagers' good primary healthcare. In addition, the provision of water supply for many villagers is a primary beneficial impact.

The adverse impacts are related to air and noise pollution from the plant. Apprehension naturally results regarding health when one believes that air pollution is causing damage to vegetation, leaving deposits of dust at the living quarters, and may be damaging to human health. These fears may or may not be justified. The health data from the local clinic do not indicate any difference in the health condition.

Measures for offsetting adverse effects

Air quality

The cyclones, baghouses, and electrostatic precipitator are generally performing well. Consideration should be given to undertaking the corrective maintenance measures for the electrostatic precipitators (ESP) recommended by Research Cottrell as these measures will ensure a longer and more efficient operating life of the ESPs and should further reduce the frequency of tripping of the ESPs; bag replacement and maintenance should be improved, and the performance closely monitored; and consideration should be given to upgrading the old ventilated baghouses, so that the emissions are from a stack or stacks which can be monitored and also will reduce local dust deposition during calm periods.

Stack emissions from liquidator 3 resulting from dross production need additional pollution control in order to reduce the arsenic trioxide emission concentration. It has been proposed that by cooling the gas prior to baghouse filtration, the efficiency of filtration would increase. This cooling could be accomplished by installation of a medium efficiency dry cyclone with modification for air cooling in the exhaust line prior to the baghouse. It may also be necessary to install a second baghouse in series or vent the baghouse to an ESP. The approach here should be step-by-step to minimize unnecessary expenditures. This means that air cooling on a pilot scale should be tested first to determine the potential increase in arsenic removal efficiency of the existing baghouse. Further steps would be dependent on the results of the pilot testing. In addition it would be a good idea to only operate liquidator 3 on windy days to increase dispersion.

A general "tightening-up'' and possibly some modifications are needed for improving shop-floor ambient air quality. This is particularly true for the electric furnaces during charging, the refining and casting area, the hardhead tank, and the area around the AI/As dross storage room and liquidator 3 (particularly during liquidating). An analysis of needs for improvement in hygiene lines, exhaust fans, protective structures, etc., is needed to enable detailed design of cost-effective facilities. A corrosion control analysis should be incorporated in the study in order to prevent further corrosion-related gas line leakage.

The baghouse and hygiene system engineering study and improvement planning is completed and detail design is underway. The construction was expected to begin in the second half of 1986.

Water pollution

The water pollution analysis shows that the only pollutants exceeding MOI effluent standards are from the laboratory and canteen. Because of the small volume of wastewater and the vast dispersion/dilution effect of the tides and currents, it is evident that the effluent does not significantly impact on the local ecology. However, the smelter could easily meet MOI standards by routing the canteen wastewater flow to a septic tank/oil trap system and pumping the laboratory wastewater to the septic tanks system rather than directly discharging to the sea. This will eliminate any direct discharge of undiluted or diluted laboratory wastewater (this is the same disposal method as is commonly used by laboratories in Bangkok).

Noise pollution

The effect of noise pollution has been evaluated by noise level measurements at various locations in-plant and in surrounding communities. Noise pollution was shown not to be an occupational hazard for workers. The normal plant operation does not have any significant effect on sound levels in nearby villages. However, periodically, there are explosions due to slag granulation which are reported to cause nuisance conditions at nearby residences. The smelter has been and is continuously making every possible effort to reduce the frequency of such explosions. The frequency has been reduced from the occurrence of explosion in 18 per cent of tappings in 1983 to 14 per cent in 1985. This results in an average of less than two explosions per week. It is possible that this is the best achievable under present processing circumstances and is thus an unavoidable impact. It is not feasible to shift processing times to ensure that the slag explosions occur during the day. The smelter is continuing to modify its processing to reduce the number of slag explosions. One of the expansion plans is a new cooling water system, for the improvement of the water pressure and water flow rate of the slag granulation system. The high pressure and the high flow rate of granulating water will reduce the chance of slag explosion and therefore reduce the frequency of slag explosion. The installation of the cooling water system is planned within 1986/87 smelter budgets.

Solid wastes

Solid waste pollution control is not a significant factor in the assessment of environmental impacts of the tin smelter because the process solid wastes are either recycled or sold as slag or dust.

Environmental monitoring

The monitoring activities are planned to provide confidence in the continuous improvements in pollution control at the smelter and to ensure that the objectives of environmental protection are met.

The plan includes monitoring of both the natural environment and public and occupational health-related parameters. The monitoring will include systematic measurement of air and wastewater discharges from the smelter as well as special periodic ambient environmental quality measurements.

The implementation of the monitoring plan will serve to provide the following:

(a) establish a database to confirm meeting applicable MOI and National Environment Board criteria and standards;

(b) ensure worker health and safety;

(c) assist in the efficient operation of the smelter by providing feedback on operation/maintenance.

The monitoring programme includes point-source sampling for all significant air and wastewater discharges and ambient air quality sampling for the shopfloor and at the two nearby villages. The monitoring programme also includes continued monitoring of drinking water quality, recording of operational problems of air pollution control facilities, recording of blast occurrences, and continuing safety/health checks. The smelter monitoring programme will commence when appropriate equipment has been identified and obtained. Periodic reports will be issued to the MOI as required.

Concluding remarks

From the overall assessment it can be concluded that, while the tin smelter operations do cause minor effects on the local environment as a result of wastewater and noise, the only significant adverse effects may be caused by air emissions. These problems can be readily overcome so that the overall adverse impacts of the smelter will be minor or possibly insignificant, especially when compared to the major social and economic benefits derived during the past 20 years of operation and which are expected to continue in the future. These benefits are enjoyed by the local population, the Upper South Region, and the nation.


1 Metal Levels Associated with Tin Dredging and Smelting and their Effects upon Intertidal Reef Flats at Ko Phuket, Thailand, Coral Reef, Chapter 1, pp. 131-137, 1982.

2 Environmental Guidelines for Coastal Zone Management in Thailand/Zone of Phuket, H. F. Ludwig/SEATEC, 1976.

3 Inception Report: Environmental Impact Assessment for Thailand Tin Smelter, prepared by SEATEC Consortium, October 1984.

4 First Progress Report, Environmental Impact Assessment for Thailand Tin Smelter, prepared by SEATEC Consortium, March 1985.

5 Manual of NEB Guidelines for Preparation of Environmental Impact Evaluations, National Environmental Board, 1979.