DU PONT (AUSTRALIA) LTD

PROPOSED SODIUM CYANIDE PLANT

Public Environmental Report

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DU PONT (AUSTRALIA) LTD

SODIUM CYANIDE PLANT

PUBLIC ENVIRONMENTAL REPORT

Prepared by:

Kinhill Engineers Pty Ltd 47 Burswood Road, Victoria Park, WA 6100

Tel. (09) 362 5900; Telex AA92722; Fax (09) 362 5627

July 1989 PE9028

PROPOSED SODIUM CYANIDE PLANT PUBLIC ENVIRONMENTAL REPORT

The Environmental Protection Authority (EPA) invites persons and organizations to make a submission on this proposal.

The Public Environmental Report (PER) for the proposed sodium cyanide plant at Kwinana has been prepared on behalf of Du Pont (Australia) Ltd in accordance with Western Australian Government procedures. The PER will be available for comment for eight weeks, beginning on 26 July 1989 and finishing on 19 September 1989.

Comments from government agencies and from the public will assist the EPA in preparing an assessment report, in which it will make a recommendation to Government.

WHY WRITE A SUBMISSION?

A submission is a way to provide information, express your opinion and put forward your suggested course of action including any alternative approach. It is useful if you indicate any suggestion you have to improve the proposal.

All submissions received will be acknowledged.

DEVELOPING A SUBMISSION

You may agree or disagree, or comment on, the general issues discussed in the PER or with specific proposals. It helps if you give reasons for your conclusions, supported by relevant data.

You may make an important contribution by suggesting ways to make the proposal environmentally more acceptable.

When making comments on specific proposals in the PER:

clearly state you point of view indicate the source of your information or argument if this is applicable, and suggest recommendations, safeguards or alternatives.

POINTS TO KEEP IN MIND -

It will be easier to analyse your submission if you keep in mind the following points:

Attempt to list points so that the issues raised are clear. A summary of your submission is helpful. ----------------- ----- -

Refer each point to the appropnate section, chapter or recommendation in the PER.

If you discuss different sections of the PER, keep them distinct and separate, so there is no confusion as to which section you are considering.

Attach factual information you wish to provide and give details of the source. Make sure your information is accurate.

Please indicate whether your submission can be quoted, in part or in full, by the EPA in its assessment report.

Copies of the PER can be obtained from Du Pont (Australia) Ltd. 87 Welshpool Road, Welshpool at a cost of $5.00 plus packaging and postage. -

Remember to include:

name address date.

The closing date for submission is 19 September 1989.

Submissions should be addressed to:

The Chairman Environmental Protection Authority 1 Mount Street Perth WA 6000 -

Attention: D. Michaelson

CONTENTS

Section

Page

SUMMARY

1 INTRODUCTION

1

1.1 Background

1 1.2 Scope and structure of the PER

2

1.3 The proponent

2 1.4 Timing of the proposal

3

1.5 Approval process 4

2 NEED FOR THE PROJECT

7

2.1 The gold industry 7 2.2 Local community and State 7 2.3 Australian economy

9

3 EVALUATION OF ALTERNATIVES

10

3.1 Alternatives to sodium cyanide in gold extraction 10 3.2 Sites 10 3.3 Product transport 17 3.4 Process technology 18

4 PROJECT DESCRIPTION 20

4.1 Plant scope and capacity 20 4.2 Process description 20 4.3 Materials handling and storage 21 4.4 Provision of services 25 4.5 By-products 25 4.6 Waste products 26 4.7 Plant layout 29 4.8 Construction 31 4.9 Operation 31

Section Page

5 EXISTING ENVIRONMENT 33

5.1 Physical and biological environment 33 5.2 Land use and planning 34 5.3 Risks and hazards 35 5.4 Airquality 35

6 ENVIRONMENTAL IMPACTS 37

6.1 Waste disposal 37 6.2 Assessment of risks and hazards 37 6.3 Social impacts 44 6.4 Impacts on groundwater 45 6.5 Construction phase 46

7 ENVIRONMENTAL MANAGEMENT AND MONITORING 47

7.1 Construction 47 7.2 Operation 48 7.3 Safety features 48 7.4 Total hazard control plan 49 7.5 Monitoring 50 7.6 Product transport 50 7.7 Auditing 51

• COMMITMENTS 52

8.1 Construction 52 8.2 Operation 53 8.3 Safety features 54 8.4 Monitoring and auditing 56

Section

Page

FIGURES

1.1 Approval process 6

2.1 Sodium cyanide demand and supply - Australasian region 8

3.1 Western Australian prospective plant sites 12 3.2 KIA prospective plant sites 14

4.1 Simplified process flow diagram 22 4.2 The bag/box storage arrangement for solid sodium cyanide 24 4.3 Proposed wastewater treatment/disposal facilities 27 4.4 Site layout for the proposed plant 30

6.1 Individual risk contours 42

TABLES

3.1 Comparative assessment of prospective sites in Western Australia 15 3.2 Comparative assessment of prospective sites in the KIA 16

4.1 Raw materials and utilities

20

6.1 Health hazards of ammonia 39 6.2 Predicted human health effects of exposure to various

concentrations of hydrogen cyanide 40

REFERENCES

GENERAL ABBREVIATIONS AND ACRONYMS

APPENDIX

A EPA guidelines

SUMMARY

Du Pont (Australia) Ltd (Du Pont) proposes to establish a $60 million plant at Kwinana to manufacture sodium cyanide in solid briquette form. The proposed plant would have a production capacity of 45,000 t/a.

The parent company of Du Pont, one of the world's oldest and most diverse industrial fu-rns, has been operating a sodium cyanide plant in Memphis for over thirty-five years and has recently commissioned a second sodium cyanide plant in Texas. Du Pont is highly experienced in the safe and efficient operation of such plants and is the the first chemical firm to receive the National Safety Council of Australia Five Star Safety Award for its facility in Girraween, Sydney.

Sodium cyanide is considered the most efficient and cost-effective means of extracting gold from ores. Until recently, the Western Australian gold industry imported all its sodium cyanide requirements. Du Pont is currently the major importer of solid sodium cyanide, distributing the product by road and rail from Fremantle. The availability of all necessary raw materials for the manufacture of sodium cyanide, together with the increasing demand for sodium cyanide from the expanding gold industry, presents a favourable opportunity for Du Pont to supply the market with locally manufactured, rather than imported, solid sodium cyanide.

Construction and operation of the proposed sodium cyanide plant would benefit not only the gold industry, but also the local community, State and Australian economies. Approximately $40 million would be spent in the local community, with associated direct and indirect opportunities for employment and training. Temporary employment for 110 people during the construction phase, and for an additional forty-three people during the operational phase, would also be provided. In addition, the range of value-added industries would be expanded through the efficient utilization of natural gas supplies as chemical feedstock, rather than as fuel.

In accordance with the Environmental Protection Act, 1986, Du Pont prepared documentation of the proposal to enable the Environmental Protection Authority (EPA) to determine the appropriate level of environmental assessment. The EPA considered that a Public Environmental Report (PER) and a risks and hazards analysis were required. The risk analysis, prepared by Det norske Veritas, is presented in a separate report, and is summarized in Section 6.2 of the PER.

Du Pont also undertook a comprehensive site selection study to determine the most suitable location for the proposed plant. Locations in Australia (Queensland and Western Australia), New Zealand and Singapore were considered. The Western Australian sites included Port Hedland, Karratha, Geraldton/Greenough, Kalgoorlie, Northam, Wundowie and Kwinana. The Kwinana area was considered the most advantageous location in terms of the site selection criteria. The selected site in Kwinana is situated adjacent to Patterson Road, north of the Western Mining Corporation nickel refinery. This site is preferred for the following reasons:

proximity to gold producers in the region;

appropriate zoning and minimal conflicts with existing land uses;

the existence of a substantial buffer zone between the plant site and the nearest residential area

the availability of natural gas, ammonia and caustic soda supplies;

accessibility to rail transport;

proximity to substantial support infrastructure and human resources in Kwinana;

proximity to an industrial facility able to utilize steam by-product.

No other site was considered to offer all these benefits.

The manufacturing technology for the commercial production of solid sodium cyanide was pioneered and developed by Du Pont. The sodium cyanide manufacturing process is based on a modified Andrussow process, which is used in the other Du Pont plants in Memphis and Texas. This process consists of the following major stages:

natural gas (minus carbon dioxide), ammonia vapour and air are mixed;

the mixed gases are burnt to produce hydrogen cyanide;

the hydrogen cyanide is reacted with sodium cyanide (containing an excess of sodium hydroxide) to produce sodium cyanide in solution form;

the sodium cyanide solution is dewatered, dried and compacted to produce solid briquettes.

Although alternative technologies are available, none are considered as safe or as efficient as the proposed method.

Natural gas would be obtained from either the West Australian Natural Gas Pty Ltd pipeline or the Dampier to Perth natural gas pipeline. Caustic soda may be obtained from the planned Petrochemical Industries Company Ltd plant, imported through the Kwinana Beach berth (via a pipeline) to an on-site 30,000 t storage tank or obtained from local suppliers. Ammonia would be piped from CSBP & Farmers Ltd's plant. Nitrogen

would be obtained from a local air separation plant by pipeline. Water would be supplied from the Water Authority of Western Ausiralia scheme water. Power requirements would be obtained from the existing 22 kV State Energy Commission of Western Australia power line system.

All waste products from the plant would be disposed of in an environmentally safe and proper manner and in accordance with the statutory requirements of the EPA.

The manufacturing process does not produce solid wastes. However, during plant commissioning, when the various flows in the process are being balanced, some solid sodium cyanide may not conform with performance specifications. This non-conforming material would be reprocessed, until it complied with established performance specifications.

Washdown, spillages and runoff wastewater would be collected in a concrete sump and then directed to decomposition ('cook') tanks, which would thermally decompose the cyanide. The treated effluent would be pumped to the cooling tower where the remaining cyanide would be vaporized; small quantities would be purged and sent to a series of evaporation ponds, which would be double lined to prevent leakage. The wastewater entering the ponds would contain less than 1.0 p.p.m free cyanide. A large proportion of the treated effluent would be reused for cooling water requirements.

Plant maintenance washings and 'first flush' stormwater would be treated as liquid effluent. Subsequent stormwater would be directed from the sump to the evaporation ponds. The evaporation ponds would have sufficient capacity to accommodate an extreme rainfall event (one in 100 year, seventy-two hour duration storm) at the end of winter when the ponds would contain the peak volume of effluent.

The gaseous wastes from the process would be vented to the atmosphere from the flare, scrubber and air heater. Gases from the flare would Consist mainly of water vapour, carbon dioxide and nitrogen; small amoutits of nitrogen oxides and ammonia may also be released. The scrubber would release air containing trace levels of ammonia, sodium cyanide and hydrogen cyanide. Dust particles would also be removed by the scrubber system. The main gaseous emissions from the air heater would be nitrogen oxides and carbon dioxide. The concentrations of all gaseous emissions would be within the national guidelines for the control of air pollutants.

The finished product would be packaged in a bag with a waterproof, polyethylene liner and an outer layer of woven polypropylene material. These bags would be packaged inside a reinforced plywood box bound by seven steel straps and would be transported in standard freight containers. This method of transport is a continuation of the current safe practice adopted by Du Pont for the distribution of sodium cyanide through the Port of Fremantle.

The risks and hazard analysis undertaken by Det norske Veritas evaluated the potential risks to the neighbouring area resulting from the establishment and operation of the proposed sodium cyanide plant. The risks were evaluated in terms of the risk assessment criteria outlined by the EPA, and the results of this assessment show that the plant would easily comply with risk levels considered to be acceptable by the EPA.

Appropriate dust suppression activities (application of water from tankers) and noise reducing devices would be used during the construction and operation of the plant to ensure that dust and noise levels complied with the requirements of the Town of Kwinana and the EPA.

Groundwater would only be used for landscaping purposes. The use of scheme water for process water and the extensive recycling of water, especially for cooling purposes, would avoid the need for groundwater utilization. Monitoring/recovery bores would allow regular sampling of groundwater to determine whether leakage between the liners of the evaporation ponds had occurred and to enable the recovery of any contaminated groundwater, should it be necessary.

Increased traffic levels during the construction and operation of the plant would not cause significant problems due to the small number of vehicles involved and the capacity of the roads in the area.

The safety of all personnel and the public would be the primary objective of the proponent. Safety features would include:

commissioning of a Hazard and Operability study before the finalization of the plant design to identify any potential hazards and operating difficulties;

minimizing the amount of hydrogen cyanide in the process system to 1.87 kg at any time;

inclusion of a secondary gas containment system around the hydrogen cyanide converter and pipework to contain the hydrogen cyanide inventory in the unlikely event of leakage;

inclusion of a surge tank between the absorber and the evaporator to allow rapid shut-down of the plant in case of blockage;

field-installed cyanide detectors.

A comprehensive monitoring programme would be implemented to sample and test all plant and works discharges, airborne emissions and ambient air quality, groundwater quality, and noise and dust levels. The findings of these monitoring programmes would be reported to the relevant regulatory authority.

Depending on the granting of all necessary approvals, construction of the plant is expected to commence in March 1990; commissioning is expected to be completed by August 1991.

iv

Section 1

INTRODUCTION

1.1 BACKGROUND

Du Pont (Australia) Ltd (Du Pont) proposes to establish a $60 million plant at Kwinana to manufacture sodium cyanide in solid briquette form. The production capacity of the proposed plant is 45,000 t/a.

With the resurgence of the Australian gold industry in recent years, the market for sodium cyanide, a chemical compound used in gold extraction, has rapidly expanded. The current demand in Western Australia is approximately 50,000-60,000 t/a. Until recently, sodium cyanide was not manufactured in Australia and had to be imported in solid briquette form. However, the recent commissioning of a sodium cyanide solution plant in Kwinana will allow some of the demand to be met by a local producer.

Du Pont is currently the major importer of sodium cyanide, and distributes the packaged product to users by road and rail from Fremantle and Kalgoorlie. Due to the ready availability of the raw materials required to manufacture sodium cyanide and the increasing demand created by the continued expansion of the gold industry in Western Australia, Du Pont proposes to supply the market with locally manufactured, rather than imported, solid sodium cyanide.

Following preliminary discussions about the proposal with the Western Australian State Government, a comprehensive study was conducted to identify the most suitable location for the proposed plant (Du Pont 1989a). The study examined a number of prospective sites overseas, interstate and within Western Australia. The Western Australian sites included Port Hedland, Karratha, Geraldton/Greenough, Kalgoorlie, Northam, Wundowie and Kwinana. On the basis of the site selection criteria, it was concluded that the Kwinana Industrial Area (MA) would be the most appropriate location. Three sites within the KIA were considered. The preferred site is adjacent to Patterson Road, north of the Western Mining Corporation Ltd (WMC) nickel refinery.

Du Pont also prepared a report outlining the general proposal for the plant and associated environmental issues (Du Pont 1989b). This was submitted to the Environmental Protection Authority (EPA) in May 1989 to enable the EPA to determine the appropriate level of environmental assessment for the project. The EPA concluded that a Public Environmental Report (PER) would be required and issued guidelines for its preparation. These guidelines are included in the PER as Appendix A.

The EPA also instructedDu Pont to prepare a risks and hazards analysis for the proposed plant. The results of this analysis, prepared by risk analysis consultant Det norske Veritas, is presented in a separate report. A summary of the risks and hazards analysis is presented in Section 6.2.

1.2 SCOPE AND STRUCTURE OF THE PER

The aim of the PER is to provide information on the proposed plant so that interested parties may have the opportunity to comment on it.

The PER covers all aspects of the proposal, and examines in detail potential environmental impacts and the means by which these would be managed. Elements of the environment are considered in terms of the plant site itself, neighbouring areas and the wider KIA.

The PER is structured as follows:

Section 1 presents a background to the proposal and the PER, details of the

/ proponent, the proposed schedule and the approval process for the project.

Section 2 outlines the benefits of the project to the gold industry, the local community, the State and the Australian economy.

Section 3 discusses alternatives considered for various elements of the project. I

Section 4 presents details of all the elements that form the present proposal, including the technology to be used, handling and storage of raw materials, the layout of the plant, and the way in which it would be constructed and operated.

Section 5 describes the existing environment.

Section 6 evaluates potential environmental impacts of the project, and includes a summary of the risks and hazards analysis undertaken for the plant by Det norske

I Veritas.

Section 7 describes the proposed programme of controls and safeguards to minimize environmental impacts.

Section 8 summarizes all commitments made in relation to environmental management.

1.3 THE PROPONENT

The proponent for this project is Du Pont, a subsidiary of one of the world's oldest and most diversified industrial firms, E.I. Du Pont de Nemours. The wide range of activities in which Du Pont is involved includes:

agricultural and industrial chemicals

2

biomedical products coal man-made fibre products industrial and consumer products petroleum and gas exploration and production petroleum refining, marketing and transportation polymer products.

Du Pont has been manufacturing sodium cyanide at a plant in Memphis for over thirty-five years and is highly experienced in the safe and efficient operation of such plants.

Du Pont has production or distribution facilities throughout the world; its parent company is located in the United States of America. The head office for its Australian operations is in Sydney, with other Australian offices in Brisbane, Melbourne, Adelaide and Perth. Du Pont has a film-finishing and agricultural chemical processing plant at Girraween (New South Wales) and has operated manufacturing facilities at Bogan Gate (New South Wales), Warkworth (New South Wales), Bajool (Queensland) and Baldivis (Western Australia). Du Pont employs approximately 400 people in Australia in marketing, administration and manufacturing.

The activities of its Australian operations include:

consumer products - such as carpet fibre; fibres for bedding apparel, swimwear, hosiery and fashion garments; and finishes for cookware and building materials;

health care/biomedical products - such as diagnostic systems; biotechnology systems; and diagnostic imaging equipment such as X-ray film and video film;

industrial materials - such as polymer film; titanium dioxide pigments; and industrial fibres and engineering plastics for the manufacture of refrigerators and vehicle parts; the latter includes a preparation site at Wetherill Park, Sydney, for laminating film used in windscreens;

packaging - air and waterproof packaging and adhesives;

printing - polyester film base, chemical proofing systems and flexographic plate systems;

agriculture - a broad range of herbicides, fungicides and insecticides;

• mining and mineral extraction - major suppliers of sodium cyanide to the gold industry and flocculants for flotation separation.

1.4 TIMING OF THE PROPOSAL

The proposed schedule for the project is as follows:

Approval: by first quarter of 1990

3

Engineering: July 1989 - June 1990 • Construction: March 1990-May 1991

Commissioning: May 1991.-August 1991.

1.5 APPROVAL PROCESS

1.5.1 STATUTORY APPROVALS AND RESPONSIBLE AUTHORITIES

The legislation that applies to the project is as follows:

The Town Planning and Development Act, 1928 (as amended) empowers the Town of Kwinana to control development under the provisions of its Town Planning Scheme. The proponent will apply to the Kwinana Town Council (KTC) for development approval ('Application for approval to commence development') and separate building approvals.

II • The Industrial Lands (Kwinana) Agreement Act, 1964 administered by the Industrial Lands Development Authority, controls the disposition of certain lands at Kwinana (including the proposed site) for industrial purposes.

The Local Government Act, 1960 (as amended) provides authority to the Town of Kwinana with respect to local planning and zoning regulations.

The Metropolitan Region Town Planning Scheme Act, 1959 (as amended) provides the State Planning Commission (SPC) with regional planning powers to control development. The proponent will submit an application for development approval via the KTC.

The Environmental Protection Act, 1986 (as amended) requires the proponent to prepare documentation of the proposal, including environmental impacts, for

Il evaluation by the public and relevant authorities before environmental approval can be granted (Section 1.5.2), and provides for the prevention, control and abatement of

- discharges into, and pollution of, the environment.

The Occupational Health, Safety and Welfare Act, 1988 provides regulations to ensure the good health and safety of both employees and the general public.

The Health Act, 1911 (as amended) authorizes the KTC to control 'offensive trades'. If the KTC classifies the proposed plant as 'noxious', the proponent will apply for registration as an 'offensive trade - chemical works'.

1 .• The Dangerous Goods (Road Transport) Regulations, 1983 are administered by the

Department of Mines, which is responsible for reviewing the design and operation of

- vehicles and transport of the product.

The Explosives and Dangerous Goods Act, 1961 (as amended), administered by the Department of Mines, regulates the on-site storage of flammable materials and

4

Section 2

NEED FOR THE PROJECT

2.1 THE GOLD INDUSTRY

Sodium cyanide is required by gold producers for gold extraction by the most technologically advanced process. At present, Australian producers must rely on importing their requirements, although some demand will in the future be met by the recently commissioned Australian Gold Reagents Pty Ltd (AGR) Kwinana liquid sodium cyanide plant. Figure 2.1 shows the relative contribution to the supply of sodium cyanide by existing and future Australian producers and the estimated level of demand for sodium cyanide in the Australasian region between 1987 and 1992. The establishment of the proposed Du Pont plant would be extremely beneficial to the growth of Australia's gold industry, with specific benefits including:

increased competition between local sodium cyanide producers, resulting in a more competitive pricing market;

increased reliability in the supply of sodium cyanide through less reliance on the imported product;

stabilized supplies of sodium cyanide, which would enhance the expansion of the gold industry, ensuring continued employment and investment opportunities;

increased product availability, allowing local gold producers to store smaller quantities of sodium cyanide at the mine sites, thus reducing the risk of loss of containment;

upgrading of local raw materials to produce solid sodium cyanide for export to the South-East Asian gold mining industry.

In addition, the solid form of sodium cyanide manufactured by Du Pont is easier to handle and transport than the liquid form.

2.2 LOCAL COMMUNITY AND STATE

The benefits to the State and the local community offered by the establishment of the proposed plant are as follows:

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Figure 2.1 SODIUM CYANIDE DEMAND AND SUPPLY - AUSTRALIASIAN REGION

a project investment of $60 million, with at least $40 million of this being spent in the local community;

increased direct employment for the local workforce in Kwinana;

increased indirect employment through support industries and the provision of goods and services;

increased on-site training of employees in specific skills, thereby enhancing the general skill levels of the workforce in the Kwinana area;

increased opportunities for local manufacturing firms to supply plant components and equipment during the construction phase;

expansion of the range of value-added industries in Western Australia through the efficient utilization of natural gas supplies;

introduction of the latest, solid sodium cyanide manufacturing technology to Kwinana

utilization of Western Australia's natural gas resource for chemical feedstock rather than as a fuel.

2.3 AUSTRALIAN ECONOMY

The Australian economy would benefit through the reduced need for large imported quantities of sodium cyanide. Furthermore, additional revenue would be generated from the export of approximately 8,000 t/a of solid sodium cyanide to markets in SouthEast Asia. This represents about 18% of the total output of the plant.

I

)

9

Section 3

EVALUATION OF ALTERNATIVES

3.1 ALTERNATIVES TO SODIUM CYANIDE IN GOLD EXTRACTION

Since the 1890s, utilization of sodium cyanide as a leaching agent has been the most efficient and cost-effective method of recovering pure gold particles from gold ore. Sodium cyanide replaced acid chlorine, which required high consumption rates (and, therefore, costs) and was not viable when compared with the new sodium cyanide technology.

Research into possible alternatives has shown that acid thiourea and ammoniacal thiosuiphate are the only promising reagents, but both methods make the process more expensive and/or more complicated, and are not as environmentally acceptable.

Sodium cyanide emerges as the only reliable and economically viable leaching agent, and this is borne out, firstly, by the fact that gold operators throughout the world use the cyanide leaching process, and secondly, by studies that continue to confirm sodium cyanide as the only practicable leaching agent.

3.2 SITES

In May 1989, the proponent commissioned a site selection study to identify the most suitable site for the proposed plant (Du Pont 1989a). This section summarizes the results of that study.

3.2.1 SITE SELECTION CRITERIA

The following criteria were used to assess the suitability of alternative sites:

social criteria:

- availability of suitably zoned land compatible with surrounding land uses I ) - availability of a suitable workforce

- access to markets;

I 10

engineering criteria:

- availability of industrial infrastructure such as power, water and transport - availability of construction and maintenance facilities;

• environmental criteria:

- availability of means of effluent disposal - visual impact of the plant on the surrounding landscape - impact on the existing environment;

investment criteria

- availability, safe storage and f.4nsport of the raw materials

- availability of markets for by-product steam - product distribution and land acquisition costs;

risk criteria:

- risk of toxic gas release, either from raw materials or product - risk of collision, fire, explosion or spillage, either of raw materials or product - proximity of residential areas - impact of spillages on the environment.

3.2.2 PROSPECTIVE LOCATIONS AND SITES

Based on plant requirements and the site selection criteria, the following hierarchy of locations and sites was considered:

international:

- Australia 2 - New Zealand

- Singapore;

within Australia:

- Queensland - Western Australia

within Western Australia (Figure 3.1):

- Port Hedland - Karratha - Geraldton/Greenough

11

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LEGEND

Prospective plant sites WYndham°'7

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Bunbury

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;.:1180 124 0 130°

FiRure3.1 WESTERN AUSTRALIAN PROSPECTIVE PLANT SITES

- Kalgoorlie - Northam - Wundowie - Kwinana

within Kwinana (Figure 3.2):

- Site A (Lot 35), a site immediately to the north of the WMC nickel refinery - Site B, a site immediately to the south of the WMC nickel refinery - Site C, a site bordering Office Road, Kwinana Beach.

3.23 ASSESSMENT OF PROSPECTIVE LOCATIONS

International

The three international locations considered for the plant are within the major gold producing areas of the Oceania region. Singapore and New Zealand would involve problems concerning importation of raw materials - particularly caustic soda and ammonia, but also natural gas in the case of Singapore. Singapore also has a severe shortage of suitable land, while New Zealand is relatively distant from other gold producing nations (Australia, Papua New Guinea, Philippines, Indonesia and Malaysia).

Australia offers the following advantages:

As a major gold producing country, markets are plentiful. All raw materials are readily available. Suitable land is readily available. It is close to the majority of the Australasian markets.

Within Australia

The two major gold producing States are Western Australia and Queensland. Western Australia has the following advantages:

There is a larger market for the product. Piped supplies of natural gas are available at a number of locations. Caustic soda and ammonia production levels are high. Construction and operational infrastructure are available at lower cost.

13

Figure3.2 KIA PROSPECTIVE PLANT SITES

3.2.4 ASSESSMENT OF PROSPECTIVE SITES

Within Western Australia

Table 3.1 presents a comparative assessment of sites within Western Australia considered for the plant.

Table 3.1 Comparative assessment of prospective sites in Western Australia

criteria Port Hedland

Kaffatha Geraldtoril Greenough

Kalgoorlie Northam Wundowie Kwinana

Natural gas No Yes Yes No No No Yes supply

Ammonia and No No No No No No Yes caustic soda supply

Availability Available, Yes At Narngulu, Limited No No Yes of suitably not suitably so increased zoned land zoned product

distribution costs

Proximity No No Yes Yes Yes Yes Yes to markets

Markets for Potential No Yes No No Potential Yes steam by-product

Based on the criteria considered, it is clear that Kwinana provides the most advantageous location for the plant.

Within Kwinana

Several sites are available at Kwinana, and Table 3.2 presents a comparative assessment of the sites in the KIA considered for the plant. Site A (Lot 35) is the preferred location.

3.2.5 THE PREFERRED SITE

Site A in the KIA has been selected for the proposed plant for the following reasons:

Western Australia is the major gold producing area in the Oceania region.

Kwinana is reasonably central to other gold producers in the region.

Site A is appropriately zoned and there are minimal conflicts with existing land uses.

15

Table 3.2 Comparative assessment of prospective sites In the KIA

Criteria

Site A

Site B

Site C

Social . Zoning and planned Same as for Site A Road traffic would use consistent with the increase compared to proposed plant and compatible Sites A and B as no with surrounding land use access to rail transport

Local area has large resident . Located a suitable distance skilled workforee from the Kwinana

township, but closer to Access to rail line minimizes the town than Sites A and 13 increase in mad traffic for finished product

Suitable separation distance from Kwinana township; adjacent to existing AGR sodium cyanide plant

Engineering Reasonable access Same as for Site A Same as for Sites A and B, to existing construction and except no access to rail for maintenance industry product transport infinstructure in Kwinana/ Rockingham area

Good access to rail, road, wharf, power and water supply

Environmental . Visual impact minor in Visual impact similar . Plant would be set further back comparison with existing to Site A as this site from Patterson Road than Sites industry. Minimum setback* also borders Patterson A or B, so visual impact would provided Road be less

Effluent can be treated and . Minimum setback* would disposed of on site apply to the Patterson Road

side of the site

No negative impact on existing environment and is consistent with surrounding land use

No negative impact on existing . Effluent can be treated and environment and is consistent disposed of on site with surrounding land use

Investment Does not requite additional No additional investment in . Considerably more investment in large ammonia large ammonia and caustic investment required due and caustic import storage import storage facilities to the need to extend facilities as these raw materials required; however, compared ammonia, caustic and are available locally with Site A, additional gas supply lines to the

investment required to bring site Minimal extensions to existing these facilities to site raw material supply pipelines required

Neighbouring industries may utilize excess by-product steam and supply steam for start-up

Risk criteria Potential risk low . Potential risk comparable with . Risk contours may spread due to relatively short Site A, although extension of over a large area depending lengths of raw material supply the existing ammonia and on the final means of pipelines and caustic supply pipelines product transport (i.e. above

may alter risk cotitours or below ground pipelines), due to the need to bring ammonia, gas and caustic supply pipelines from the western side of Patterson Road to the site

* The proponent recognizes the recommendations set out in improvement Plan No. 14 (State Planning Commission 1988), which calls for a minimum 20 in setback from Patterson Road.

Residential areas are at least 2 km from Site A and there is a substantial buffer zone of vegetation.

Piped supplies of natural gas, ammonia and caustic soda are available immediately adjacent to Site A.

Rail transport for the product is available immediately adjacent to Site A.

Site A is immediately adjacent to an industrial facility that can supply and utilize steam.

The risks associated with transport and storage of natural gas, ammonia and caustic soda are least at Site A.

The risks associated with transport of solid sodium cyanide are least at Site A.

Support infrastructure and human resources are readily available in Kwinana.

Other industhes and personnel familiar with risk control and emergency response are readily available close to Site A.

The visual impact of the proposed plant would be least at Site A.

No other site within Western Australia or the Oceania region offers all of these benefits, which form the basis of a financially viable project.

The Department of Resources Development has indicated that the purchase of the plant site (Site A) by Du Pont would be subject to the following conditions:

determination of the land area required by Du Pont for the effective operation of the plant

mutual agreement between the State Government and the WMC for a suitable land swap so that the proposed site is available for purchase by Du Pont

SPC approval of the subdivision of the proposed service corridor land and other land required for infrastructure purposes. The resultant terms and conditions must be acceptable to the Industrial Lands Development Authority.

3.3 PRODUCT TRANSPORT

Ships would be used for product distribution overseas. The only alternative, transport mode for product distribution in the export market is by air freight. Cost comparisons indicate that the air freight option is prohibitively expensive relative to the shipping option. -

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Within Australia, the available alternative modes of product transport are by rail or road. Where possible, rail would be used to transport the freight containers interstate and to rail terminals nearest gold producing areas. Road transport would be used to deliver the freight containers to the gold processing plants. Where the existing railway network does not extend to gold producing areas, road transport would be used between Kwinana and the processing plant. This arrangement has been used by Du Pont in Western Australia for a number of years to transport imported solid sodium cyanide to gold plants. No practical alternative to this product distribution is available, although shipping could be used to transport the product to remote coastal areas where railways do not extend.

Similar modes of transport are used by producers of liquid sodium cyanide, which is potentially more hazardous than the solid form to be manufactured by Du Pont.

3.4 PROCESS TECHNOLOGY

3.4.1 ANDRUSSOW PROCESS USED BY DU PONT

Since the early 1950s, Du Pont has developed and operated the Andrussow process for manufacturing solid sodium cyanide at its Memphis and Texas City plants in the United States of America. Du Pont proposes to use this process in the Kwinana sodium cyanide plant because of the increased safety, reduced environmental impact and reduced investment associated with the process.

The Andrussow direct absorption solid sodium cyanide process proposed for this plant (Section 4.2) reacts natural gas, ammonia and air over a platinum/rhodium catalyst to form a gas stream containing hydrogen cyanide. This gas stream is directly absorbed into a caustic soda solution to create a sodium cyanide solution, ensuring that there is a minimum inventory of hydrogen cyanide in the process. This solution is concentrated to form sodium cyanide crystals. The crystals are then filtered and dried using hot air and are compacted to form solid sodium cyanide briquettes.

3.4.2 VARIATIONS ON THE ANDRUSSOW PROCESS

The following are variations on the Andrussow sodium cyanide process.

Andrussow liquid sodium cyanide process

This process is similar to the proponent's process except that the sodium cyanide remains in liquid form and is not concentrated into solid briquettes.

Andrussow sodium cyanide process using by-product hydrogen cyanide

This process uses concentrated hydrogen cyanide as a feedstock. The feedstock may be purchased as a raw material or is often found as a by-product of acrylonitrile manufacture. Relatively large amounts of hydrogen cyanide are generally stored to feed the process. The hydrogen cyanide is absorbed into a caustic solution and processed to form either liquid or solid sodium cyanide, as described in Section 3.4.1.

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3.4.3 OTHER PROCESSES

Other technologies that have been employed to manufacture sodium cyanide include the following.

The Degussa process

This process reacts methane with ammonia inside platinum-coated ceramic tubes, which,, are externally heated to 1,300°C. The process has the disadvantage of relatively high maintenance costs allied to regular tube failures.

The Fluohmic process

This differs from the Andrussow process in that the heat for the primary reaction between ammonia and a hydrocarbon to form hydrogen cyanide is provided by electrical energy in the form of an arc sustained in a fluidized bed of carbon. This reaction also produces hydrogen and soot. The hydrogen can be used for ammonia synthesis, but the soot must be removed, treated to remove cyanide and then disposed of. The fluid bed arc furnace requires a degree of maintenance; however, the process does not require catalysis at its high operating temperature.

3.4.4 ADVANTAGES OF THE ANDRUSSOW PROCESS USED BY DU PONT

It is proposed to use the Andrussow direct absorption solid sodium cyanide process because it offers a number of advantages compared with other available process technologies, namely:

minimum possible hydrogen cyanide inventory in the process minimum possible liquid sodium cyanide inventory does not create hazardous emissions or contaminated solid waste low maintenance requirements.

In all of the alternative processes referred to, the sodium cyanide can be manufactured as a liquid solution or it can be processed further into a solid form. It is proposed to manufacture only solid sodium cyanide because the proponent considers that it is safer to transport sodium cyanide as a solid rather than as a liquid.

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Section 4

PROJECT DESCRIPTION

4.1 PLANT SCOPE AND CAPACITY

The proposed plant would produce 45,000 t/a of sodium cyanide in solid briquette form.

Raw materials and utilities required for production are shown in Table 4.1.

Table 4.1 Raw materials and utilities

Requument Quantity

Natural gas 42.45x10 6 m3/a . Caustic soda 85,000 t/a (50% basis) Ammonia 29,000 t/a Electricity 3 MW Water 259,000 m3/a

4.2 PROCESS DESCRIPTION

The proponent pioneered the commercial production of solid sodium cyanide and developed the technology to become the world leader in this area. While alternative technologies are available (Section 3.4), none has been developed to the same degree of safety and efficiency, and with the same background of production experience, as that proposed for the plant.

Thesodium cyanide manufacturing process is based on a modified Andrussow process as used by the proponent at its sodium cyanide facility at Memphis for over thirty-five years and has been modified to incorporate the latest technology for the Kwinana plant. The process, in this application, involves direct absorption of converter gas into sodium cyanide solution.

If the carbon dioxide in the natural gas supply to the plant were not removed, calcium carbonate would form and would be present in the product at a level of about 4%. Such product would be perceived by the market as inferior, and therefore, the plant would incorporate a diethanolamine carbon dioxide removal system to strip the carbon dioxide from the natural gas supply.

wil

The simplified process (Figure 4.1) commences with the vaporization and heating of liquid ammonia. The heated (120°C) ammonia vapour is combined with natural gas and then filtered and mixed with filtered compressed air. This gas mixture enters a converter, where it is passed through a platinum/rhodium catalyst to produce hydrogen cyanide gas. The temperature of the hydrogen cyanide gas mixture is reduced from about 1,100°C to about 230°C in a waste heat boiler connected to the converter. Steam from the waste heat boiler would be used in separate process operations.

The dilute hydrogen cyanide gas stream is directed to an absorber column, where it reacts with a sodium cyanide solution that contains excess sodium hydroxide. The resultant reaction between the hydrogen cyanide and the sodium hydroxide produces additional sodium cyanide in solution form.

Gas from the absorber column is directed to the flare stack, which is connected to the top of the absorber, and is burned. Sodium cyanide solution is continually pumped from the absorber column to a vacuum evaporator (crystallizer), where it is concentrated to a slurry containing about 8% precipitated sodium cyanide. Sodium hydroxide is continually fed over two sieve trays in the top of the crystallizer to scrub out any hydrogen cyanide in the vapour, the sodium hydroxide is then collected and fed to the absorber.

The slurry is dewatered and dried with hot air in a rotary filter/mixing conveyor. system. The resultant crystals are pneumatically conveyed to a briquetter system, where they are compacted into solid briquettes (32 mm x 32 mm x 16 mm). The briquettes are cooled to about 80°C in the screener with chilled air. The product is then packaged.

Air emissions from the process are treated and vented through either a flare (in the case of gases) or a three-stage reverse flow scrubber (in the case of particulates). Liquid effluent from the process is treated to reduce any free cyanide to permissible levels and is then discharged to on-site evaporation ponds. The wastes from the production, treatment and disposal of solid sodium cyanide are described in Section 4.6.

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/ 4.3 MATERIALS HANDLING AND STORAGE

4.3.1 RAW MATERIALS

The raw material requirements for the proposed plant are itemized in Table 4.1.

Natural gas would be obtained from either the West Australian Natural Gas Pty Ltd pipeline or the Dampier to Perth natural gas pipeline, both of which run through the KIA.

Caustic soda could be obtained from the Petrochemical Industries Company Ltd (PICL) plant when it comes onstream. Pending further commercial considerations, Du Pont may construct a 30,000 t capacity caustic soda storage tank, with a pipeline extending from the Kwinana Beach berth to pipe imported caustic soda to the storage tank. An alternative option is the purchase of caustic soda from a local supplier; this would remove the need for an on-site caustic soda storage tank.

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Air exhaust 31,300 kg/h

Scrubbing

'Air

Briquette Cooling

Packaging

6.700 kg/h Solid sodium

cyanide bnquettes

CO2 Evaporation ponds

4 A

Natural gas I I Flare

'Washdown' Waste I Waste ga1

Treatment.

3,600 kg/h rj CO2 Removal

__________ _ ___ Caustic Mixer Convener Exit gas

11,000 kg/h Absorber Vapour

13,500 kg/h t Waste Heater I Boiler

Air

3,700 kg/h Air NaCN Vacuum Filtration 32,700 kg/h solution

To other parts of 4,650 kg/h

3,000 kg/h

Waier Air

Heater 11,400 kg/h

Air

Subject to further negotiations, ammonia would be imported through CSBP & Farmers Ltd's (CSBP) bulk storage facilities. This would be piped to the proposed plant by using either existing ammonia pipelines (running to the WMC nickel refinery) with an off-take to the proposed plant, or a new pipeline from the ammonia storage tank to the proposed plant. Only small quantities of sodium hypochlorite would be required for effluent treatment; this would be transported to the plant in solution form in drums.

Nitrogen for purging the converter and absorber system would be obtained from a local air separation plant by pipeline.

Water requirements would be met from existing scheme water supplies provided by the Water Authority of Western Australia (Water Authority); power requirements would be met by the existing 22 kV power line system provided by the State Energy Commission of Western Australia (SECWA) (Section 4.4).

Steam to start-up the process (ammonia vaporization, evaporator vacuum) may be obtained from the WMC, and may be supplemented with excess steam from the waste heat boiler. As only about 900-1,800 kg/h of steam would be required for start-up, a small boiler (4,500 kg/h capacity) would be installed.

4.3.2 FINISHED PRODUCT

On-site storage of the finished product (sodium cyanide briquettes) would be in a 2,800 t capacity undercover warehouse. The sodium cyanide briquettes would be packaged by the bag/box method, which involves an inner packaging and an outer packaging. The outer layer consists of a woven polypropylene material with attached lifting hoops, while the inner layer is a waterproof polyethylene liner. These bags are placed inside a plywood box (16 mm thick) with reinforced internal corner bracing. Each box is bound and strengthened with seven bands of steel strapping. The gross weight of the bag/box package is 850 kg. This packaging, under the Australian Code for the Transportation of Dangerous Goods by Road and Rail, is termed 'Intermediate Bulk Container' (IBC). Figure 4.2 shows an example of the bag/box arrangement. One month's inventory of IBCs would be kept in the undercover warehouse at any one time.

The IBCs would be transported in standard freight containers. Each freight container would contain twenty IBCs (i.e. 20 x 850 kg), stored two abreast and two high. Each freight container would have two emergency information panels.

Sodium cyanide has been imported into Australia and distributed by Du Pont in IBCs for over three years.

Subject to regulatory approval, 1,360 kg net steel 'fib-bins' may also be used for the transportation of sodium cyanide briquettes for distribution by road and rail. The fib-bins would be 1.1 m x 1.3 m x 1.7 m and could be stored on concrete pads outside the undercover warehouse. One months' inventory of fib-bins, equivalent to about 2,200 fib-bins, would be maintained on site at any one time.

The sodium cyanide briquettes would be distributed by road, rail and sea to users in Australia, Papua New Guinea and South-East Asia.

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THE BAG

THE BOX

Fic'uri? THE BAG/BOX STORAGE ARRANGEMENT FOR SOLID SODIUM CYANIDE

4.4 PROVISION OF SERVICES

4.4.1 ELECTRICITY SUPPLY

The supply of electricity required to operate the plant (3 MW) would be obtained from the existing SECWA 22 kV power line system. This power supply network has been established to accommodate industrial development and has the capacity to provide an additional 3 MW without requiring major upgrading of facilities.

4.4.2 WATER SUPPLY

The KIA is supplied scheme water from the metropolitan network of trunk, distribution and reticulation mains. The Water Authority has indicated that the existing system has the capacity to supply the process water requirements of the proposed plant (259,000 m3/a or 710 m3/d). The water is of good quality: Total Dissolved Solids (TDS) vary between 300-500 g/m3 and dissolved iron content is less than 0.2 g/m3.

4.4.3 ACCESS

The KLA provides road, rail and sea access. Westrail's rail network includes lines that service Alcoa of Australia Ltd (Alcoa), the SECWA power station, Australian hon & Steel Pty Ltd (AIS), CSBP, the WMC, Co-operative Bulk Handling Ltd (CBH) and a number of small industries.

Road access to the area is provided by several major roads. There are also proposals for the construction of a number of major roads in the future, including the Kwinana Freeway extension and the Fremantle—Rockingham and the Perth—Bunbury Highways. The area is well serviced by local and Perth-based road transport companies.

Commercial shipping access through the Cockbum Sound is regulated by the Fremantle Port Authority. Access is through a single channel, approximately 150 m wide and 14 m deep, between the Success and Parmelia Banks. There are nine cargo berths on the eastern side of the Sound: one at Alcoa, two at AIS, three at the BP refinery, two at Fremantle Port Authority's bulk cargo jetty and one at CBH.

4.5 BY-PRODUCTS

The operation of the plant would produce commercial quantities of steam as a by-product. Steam production is expected to be approximately 11,300 kg/h at 1,200 kPa. Excess steam from the process operations could be used to drive the converter system air compressor, or alternatively, could be sold to a neighbouring plant, such as the WMC. If the excess steam is not used or sold, consideration may be given to condensing it and reusing it in the waste heat boiler connection to the converter.

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4.6 WASTE PRODUCTS

4.6.1 SOLID WASTES

Solid wastes would be limited to product that did not comply with performance specifications, and contaminated packaging material. The non-conforming solid sodium cyanide product would be produced during the short period while the plant is being commissioned and the various flows are being balanced. This material would be reprocessed to produce solid sodium cyanide that complies with the appropriate performance specifications. Contaminated packaging material would be decontaminated with neutralizing solution prior to disposal at an approved sanitary landfill site.

Domestic solid wastes would be disposed of in the normal manner, namely, by arrangement with an industrial waste bin contractor.

4.6.2 LIQUID WASTES

Alternatives

The proponent has evaluated the alternatives available for disposal of liquid effluent from the plant. These alternatives are:

discharge effluent to Point Peron pipeline. This alternative was explored with the Water Authority, but was rejected due to technical and capacity problems associated with injection into the pipeline;

reuse of effluent by other industries. Due to the effluent containing very small amounts of cyanide, this effluent could not be economically used by other industries;

discharge of effluent to evaporation ponds. This alternative is regarded as viable and environmentally sound; however, the pondage required covers a large area of land;

recycling of effluent in the process with a small purge to evaporation ponds. This option has been chosen because it minimizes the area required for evaporation ponds. It also conserves water and is environmentally sound.

Process wastewater

The proposed wastewater treatment/disposal facilities are schematically shown in Figure 4.3. Washdown, spillage and runoff wastewater would be collected from the processing and storage areas by using bunding, concreted areas and appropriately designed concrete trenches which direct wastewater towards a tank inside a concrete sump. The wastewater in the sump tank would be pumped to one of three (150 ML) decomposition ('cooke) tanks to thermally decompose the cyanide. Steam under pressure would be added to the solution through nozzles at the base of the decomposition tanks to promote mixing and to reduce the cyanide content of the wastewater. The solution would be heated to 95-100°C,

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Air Water vapour

Hypochiorite Hydrogen cyanide treatment system

Make-up water

Inline cyanide detecter ______ Cooling tower

Vent ammonia to flare stack Purge

1,350-2,250 L/h <1.0 P.P.M. Cyanide

Evaporator vacuum/ vaporizing

condensmg system

4 (....),

All other cooling water requirements

Evaporation ponds

Monitor(s) & piping

\ / for pumping directly

\ Processing/storage areas to ponds during rains

Sump

Figure 4.3 PROPOSED WASTEWATER TREATMENT/DISPOSAL FACILITIES

ensuring a decomposition rate of 4% of the sodium cyanide per hour. Ammonia would in the decomposition tanks would reduce the cyanide concentrations to 50 p.p.m. sodium cyanide.

After testing for cyanide concentrations, the treated effluent would be pumped, at a controlled rate (1,350 L/h), from the decomposition tanks to the cooling tower, where most of the remaining cyanide would be vaporized. The expected concentration of hydrogen cyanide in the cooling tower airstream is less than 1.0 p.p.m. The cooling tower water would have a hypochiorite dosing system as a back-up safeguard to further reduce cyanide concentrations in the wastewater. About 13,950 L/h of water vapour containing 10 p.p.m. cyanide would be condensed from the evaporator and reused as cooling water. Purges (1,350-2,250 LJh) would be taken from the cooling tower system and pumped to a series of evaporation ponds. The concentration of sodium cyanide in the solution entering the evaporation pond would be less than 1.0 p.p.m. free cyanide.

The relatively low annual evaporation, wet winters and the expected volume of discharged wastewater would necessitate a series of evaporation ponds with a total area of about 5 ha. These evaporation ponds would be lined with a high-integrity double lining to prevent leakage of wastewater from the ponds. In addition, the space between the two liners would be monitored for cyanide. Spare pond capacity has been included in the design so that in the unlikely event of leakage, the entire contents of any pond could be transferred to another pond. As an additional back-up, monitor/recovery bores would monitor the area for groundwater contamination.

Plant maintenance washings and 'first flush' stormwater from the process plant and product storage area would also be contained and treated as liquid effluent. Following the first flush, stormwater from heavy rains would be pumped directly from the sump tank to the evaporation ponds. All pumps and piping would be appropriately sized for heavy rain storms. Monitors would be installed between the sump tank and the evaporation ponds to measure the amount of water being pumped and the quality of the water, including cyanide concentration.

Although the inflow of wastewater from the plant to the evaporation ponds would be fairly constant, the evaporation rate would vary according to the time of year: evaporation is lowest during the winter months when rainfall is highest. The evaporation ponds would usually contain the greatest volume of water at the end of winter, and would, therefore, have to provide sufficient capacity to accommodate runoff from an extreme rainfall event (a one in 100 year, seventy-two hour duration storm) at that particular time of year.

Domestic sewage

Domestic sewage from amenity facilities would be treated in septic tanks in accordance with the requirements of the Town of Kwinana and the Water Authority.

4.6.3 GASEOUS WASTES

Gaseous wastes would be emitted from the flare, the scrubber and the natural gas fired air heater. These would be vented to the atmosphere.

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Emissions from flare

Under normal operating conditions, the gases discharged from the flare (36,280 kg/h) would consist mainly of water vap6ur, carbon dioxide and nitrogen, which are formed from combustion in the flare of the gases passing from the absorption tower. Small quantities of nitrogen oxides and ammonia would also be released with the flare gases. The main contributors to the flare gases are the vents of the sodium cyanide decomposition tanks. The flare stack system would burn the full waste gas stream and vent streams from the decomposition tanks. At times, full flow from the converter/waste heat boiler may also be diverted to the flare stack. The flare would be approximately 98% efficient in destroying ammonia and hydrogen cyanide. The velocity of the exit gas from the flame would be 11.3 m/s, and the temperature of the gas would be 1,000°C.

Emissions from scrubber

Air containing trace levels of ammonia, sodium cyanide and hydrogen cyanide would be discharged from the scrubber at a rate of 22,675 kg/h. The scrubber has a 99% removal efficiency for sodium cyanide and a 98% removal efficiency for hydrogen cyanide. The exit gas would have a velocity of 28.4 m/s and a temperature of 52°C. Dust particulates would be removed from the process air streams by the scrubber system, which has a 99% removal efficiency.

Emissions from air heater

Gaseous emissions from the air heater would consist of nitrogen oxides and carbon dioxide. Carbon dioxide is not normally considered an atmospheric contaminant and, due to the nature, quantity and method of discharge of this emission, no significant impacts on the surrounding area would occur. Nitrogen oxides are formed and released in all common types of combustion (Section 5.4).

Emissions during start-up and shut-down

During start-up and shut-down, the converter gas is discharged to the flare where the gases are destroyed, as described in 'Emissions from flare'.

Level of emissions

The concentrations of all emissions from the plant during normal operation would be within the levels set out in the national guidelines for the control of air pollutants, prepared by the National Health and Medical Research Council (NHMRC), 1986.

4.7 PLANT LAYOUT

A provisional layout for the proposed plant site is shown in Figure 4.4. The height of the tallest component of the plant, the flare stack, would be approximately 30 m.

29

32 .

32

c0cH

32 1

railroad spur

r-14- I I.oJ I°r1

19 16 15

ooI: 0DllII 020. U 21

r D

3l

32

WMC NICKEL REFINERY

5

Future services 32

corndor C

V

32

Pioneer Road

Plant North

LEGEND 1 Caustic storage 2 Cooling tower 3 Demineralized water storage tank 4 Firewater storage tank 5 Process control area 6 Open storage area 7 Equipment storage 8 Container & fib-bin loading 9 Vacuum pumps 10 Rotary filter area 11 Nitrogen storage 12 Cyanide solution tank 13 Caustic solution tank 14 Cook tanks 15 Evaporation area 16 Flare 17 Water treatment area 18 Waste gas boiler 19 Natural gas area 20 Washwater tank 21 Airheater 22 Absorber 23 Converter 24 Ammonia area 25 Safety equipment storage area 26 Container & fib-bin storage & rail

loading 27 Administrative building 28 Parking 29 Changerooms 30 Guardhouse 31 Ammonia storage 32 Evaporation ponds

Patterson Road

0 50m ' L-4

Scale

Figure 4.4 SITE LAYOUT FOR THE PROPOSED PLANT

4.8 CONSTRUCTION

The construction of the sodium cyanide plant and associated facilities would take fifteen months and would require a peak temporary workforce of 110 personnel. The services of contract and/or permanent technical, professional and managerial consultants or staff would be needed to oversee the construction of the plant.

All construction materials and practices would strictly comply with relevant Australian or, where Australian codes do not exist, internationally accepted codes of practice relating to sodium cyanide processes and facilities. Where existing Du Pont codes require higher standards, these would be used.

Initial construction activities would involve site earthworks, levelling and compaction, and would utilize equipment common to most industrial site preparation operations.

Plant construction would involve the erection of buildings and the assembly, using bolted or welded connections, of pre-fabricated process components and pipelines.

4.9 OPERATION

Du Pont currently operates a sodium cyanide plant in Memphis and has recently commissioned a second plant in Texas, which is similar to the basic design proposed for Kwinana. Therefore, the proponent has considerable experience with management systems appropriate to the manufacture of sodium cyanide.

The plant would be designed for Continuous operation, except during maintenance shut-downs. The efficiency and stability of the plant's operation would be maximized by the use of computer control systems, regular preventative maintenance, duplication of selected equipment items, and safeguards such as back-up systems and provision for emergency shut-downs.

A total operating workforce of forty-three personnel would be required to operate and maintain the plant. These personnel would be engaged in the following activities:

continuous operations (in shifts) maintenance transportation administration security miscellaneous duties.

Most of the workforce would be drawn from the local area, although some experts may be transferred from the proponent's Memphis plant to assist with start-up and training. It is anticipated that there would also be a need for ongoing liaison with professional staff associated with the design and documentation of the plant.

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Prior to plant commissioning, all personnel would be subject to an extensive hazards and operations training programme designed to ensure safe operating practices. All employees would also be trained in emergency procedures.

Du Pont expects the proposed plant to be operated to the same high standard as its Girraween facility (Sydney), which is the first chemical company to receive the National Safety Council of Australia Five Star Safety Award.

The operation of the plant would contribute towards the sharing of acquired knowledge with other established processing industries, thereby further improving the transfer of technology within the Kwinana area.

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Section 5

EXISTING ENVIRONMENT

5.1 PHYSICAL AND BIOLOGICAL ENVIRONMENT

5.1.1 CLIMATE

Kwinana has a climate characterized by a mild wet winter and a hot dry summer. The mean monthly maximum temperature during summer-is about 27°C, while the mean winter minimum is about 10°C.

Average annual rainfall in the Kwinanã area is 790 mm, approximately 70% of which occurs between May and August. Rainfall patterns are characterized by heavy downpours; the maximum rainfall recorded in one hour is 48 mm. Annual evaporation is 2,000 mm.

Wind direction data recorded at the Wattleup base station between July 1979 and June 1980 indicate that fresh to strong morning easterlies and afternoon south-westerlies are characteristic during summer, while winter wind directions are significantly more variable.

The Kwinana air modelling study (Department of Conservation and Environment 1982) provides a more detailed description of the existing atmospheric and meteorological conditions, together with atmospheric pollutant levels and distribution in the Kwinana area.

5.1.2 LANDFORMS AND SOILS

The area containing the three possible sites is located over the Becher-Rockingham beach ridge plain, which comprises a section of the Quindalup Dune System. This coastal dune formation of unconsolidated aerolian deposits has a low undulating relic foredune topography that slopes towards the north-west.

The Safety Bay sand found in the area is characterized by white, medium-grained calcareous sand which overlies limestone at relatively shallow depth.

5.1.3 HYDROLOGY

Surface water runoff in the area is small due to the porosity of the sandy soil and underlying calcareous material; this allows rapid infiltration of rainwater to the underlying shallow unconfined aquifer.

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Based on interpolation of the Water Authority's groundwater contours in the Kwinana area, the area has a groundwater level of between 2.5 in and 3 m Australian Height Datum. The Geological Survey of Western Australia (Geological Survey) indicates that the depth to groundwater in the area is approximately 5 in; the direction of groundwater flow is towards the north-west.

The Geological Survey calculates that the groundwater salinity in the area is about 1,000 mg/L TDS; available groundwater supplies are therefore brackish. The estimated limit of the shallow (less than 30 in deep) saline wedge extends approximately 1 km inland from the coast. The saline wedge is located just west of the site.

5.2 LAND USE AND PLANNING

5.2.1 ZONING

The preferred site (Site A) is zoned industrial under the Metropolitan Region Scheme. The MRS indicates that adjacent land to the west has been zoned special industrial, while land to the north, east and south of the site has been zoned industrial.

The preferred site is located within industrial zoned land under the Town of Kwinana Town Planning Scheme No. 1.

5.2.2 LAND USE

Residential

The nearest residential areas are 2 km to the south-west, at Rockingham, and 3 km to the east, at Kwinana New Town. The coastal residential areas at Rockingham are separated from the preferred site by the CBH grain terminals and the WMC's nickel refinery. Kwinana New Town is screened from the industrial strip by a ridge of well-vegetated dune.

Industrial

The existing major operations in the KIA are as follows:

BP Refinery (Kwinana) Pty Ltd Kwinana Nitrogen Company Pty Ltd CSBP AGR WMC Coogee Chemicals Pty Ltd BHP Steel International Group/Australian Iron & Steel Pty Ltd Commonwealth Industrial Gases Ltd CBH SECWA Alcoa

34

Nufarm Chemicals Pty Ltd Cockburn Cement Ltd CBI Constructors Pty Ltd Wesfarmers LPG Pty Ltd Electric Power Transmission Pty Ltd Transfield (WA) Pty Ltd Steel Mains Pty Ltd ICI Australia Operations Pty Ltd.

Recreation

The nearest important recreational resource to the preferred site is Kwinana Beach and the adjacent Wells Park. A draft coastal management plan (Department of Conservation and Environment 1984) has been prepared for the region to ensure that its attributes are protected and enhanced in the future.

5.3 RISKS AND HAZARDS

The State Government, through the Department of Resources Development, commissioned a cumulative risk study of the KIA in 1986, which was updated in 1988 (Technica 1987). The original report covered the existing level of risk and included fourteen major industries in the KIA (the 'Base Case'); the update included five additional industrial developments. The conclusions of this study showed that, following the relocation of residents from Kwinana Beach, the present individual risk levels associated with the industries in the Kwinana region are within levels considered acceptable by the EPA.

The study also considered the impact of a number of proposed industrial developments and found that, although there would be a small increase in individual risk, the predicted risk levels would be well within those considered acceptable by the EPA.

It is intended that the cumulative risk assessment be updated periodically to give an overview of the level of risk to the local population generated by processing, storage and transportation of hazardous materials. Extracts from the preliminary risk analysis (Section 6.2) would be compiled so that the contribution of the proposed Du Pont plant to cumulative risk can be assessed.

5.4 AIR QUALITY

The proposed plant would be situated within the most important heavy industrial complex in Western Australia. Several of the industries in this complex discharge air pollutants, including sulphur dioxide and nitrogen oxides.

Sulphur dioxide is a colourless, pungent gas; its odour has been responsible for numerous complaints by the residents in the surrounding area. Several industries in the vicinity of the plant site discharge sulphur dioxide, and the emission level has been monitored over several years by the EPA. This level has decreased significantly during

35

the past five years, predominantly due to several industries converting from oil to natural gas as a feedstock. When other companies implement their plans to reduce the level of sulphur compound emissions, there should be a further decrease in sulphur dioxides.

Nitrogen oxides are formed and released in all common types of combustion and are introduced into the atmosphere from furnace stacks and similar sources. The most common nitrogen oxides are nitric oxide (a colourless, odourless gas) and nitrogen dioxide (an orange-brown gas with a pungent odour), and these are discharged by several industries in Kwinana.

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Section 6

ENVIRONMENTAL IMPACTS

6.1 WASTE DISPOSAL

6.1.1 SOLIDS

The plant would produce solid wastes that could be reprocessed to comply with the appropriate performance specifications.

6.1.2 LIQUID

Under normal operating conditions, the process wastewater would contain less than 1.0 p.p.m. free cyanide, which would be contained in a series of leak-proof, lined evaporation ponds.

Washings from the plant area, runoff and spillages would be either returned to the process or treated as liquid effluent.

The extent of recycling and reuse of wastewater and the appropriate use of evaporation ponds would ensure that potentially contaminated wastewater was not discharged into the Cockburn Sound or the groundwater table. No significant environmental impact would result from the treatment of liquid wastes (Section 4.6.2).

6.1.3 GASES

As outlined in Section 4.6.3, the plant would not discharge hazardous gases in concentrations exceeding NHMRC guidelines. A secondary gas containment system would be installed around the converter, waste heat boiler and exit gas pipeline to contain the hydrogen cyanide inventory in the event of a credible leak from this equipment. The containment system would allow the process to be shut down, if necessary.

6.2 ASSESSMENT OF RISKS AND HAZARDS

As a condition to the assessment for environmental approval, the EPA requested that a hazards and risks analysis be carried out for the project.

Quantitive risk analysis is the use of probability mathematics to determine the risk or threat a system poses to people and property. Its primary function is to provide the plant with the maximum safety for its operation; this, in turn, provides the public and operators

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with quantified risk levels. This is achieved by identifying potential hazards (i.e. listing possible mishaps), evaluating the frequency at which these are likely to occur (quantification) and determining the extent of impacts (damage or injury) likely to be caused (consequence analysis). Options for minimizing risks are considered at the design stage.

/ The identification section of the analysis determines potential hazards in the system; the quantification and consequence analyses assess the seriousness of the event and can be used to compare project alternatives such as sites and treatment processes.

Det norske Veritas was appointed to undertake a preliminary risk analysis to assess the potential impact of hazardous chemicals used and stored in the proposed complex. The report is presented ma separate report and is summarized in Section 6.2.3. Conventional risk analysis techniques were used to identify hazards associated with the plant, and a number of failure cases leading to the release of toxic or flammable materials were analysed for frequency and consequence.

6.2.1 HAZARDS ASSOCIATED WITH SODIUM CYANIDE PLANTS

As the risk analysis is primarily concerned with the impact of the plant on the surrounding environment, discussion of hazardous events focusses on those chemicals that would be present in quantities sufficient to cause potential risks to surrounding areas in the event of accidental release.

This section provides a general discussion of the properties of a number of process materials with potential for off-site effects.

Ammonia

Ammonia, one of the principal feedstocks, is a pungent, toxic gas which is highly irritating to humans if inhaled and can cause permanent respiratory tract damage or fatality at high concentrations.

At ambient temperature and pressure, ammonia is a colourless gas which is lighter than air. It would be piped to the plant as a liquefied gas under pressure via a pipeline of approximately 2.5 km. Any liquid ammonia spill would evaporate rapidly and would possibly form a dense (i.e. heavier than air) cloud of ammonia/air vapour. Liquid ammonia also causes severe cold burns on contact with the skin.

The flammable range of ammonia is 15-28% volume in air. The minimum ignition energy is 100 MJ, which is high, therefore, ammonia is flammable, but not readily so.

The toxic effects of ammonia are summarized in Table 6.1.

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Table 6.1 Health hazards of ammonia

Vapour concentration General effect Exposure period (p.p.m./volume)

25* Odour, detectable by most persons Maximum eight hour working period

100 No adverse effect for average worker Deliberate exposure for long periods not permitted

400 Immediate nose and throat irritation No serious effect after thirty to sixty mintues

700 Immediate eye irritation No serious effect after thirty to sixty mintues

1,500 Convulsive coughing, severe eye, Could be fatal to some people after nose and throat irritation thirty mintues

2,000-5,000 Convulsive coughing, severe eye, Could be fatal after fifteen-minutes, nose and throat irritation although no recorded fatalities

below 5,000 p.p.m.

5000-10,000 Respiratory spasms Could be fatal within minutes Rapid asphyxia

1 11,500 LC 50' 30 (lethal concentration to 50% of healthy population exposed for thirty minutes)

* This is the present Threshold Limit Value (TLV) :1 ppm. = 0.72 Fng/m3. For the preliminary risk analysis, probit equation.s for average (healthy) and vulnerable populations were used in assessing probability of fatality. The following toxic concentrations were used as levels of interest in dispersion calculations:

10,000 ppm. - LC50

1700 ppm. - Lethal concentration low, emergency level. 1,700 ppm. has been considered to be the lowest concentration level at which fatality could be expected. Recent toxicity work indicates that this is conservative.

500 p.p.m. - Immediately Dangerous to Life and Health (IDLH), irritant effects.

Hydrogen cyanide and sodium cyanide

Hydrogen cyanide exists as a gas in this process. It would be present only as a transient component in the reactor outlet mixture flowing into the absorber, where the majority of it reacts to form sodium cyanide. Only 1.87 kg of hydrogen cyanide would be present in the plant at any time.

Hydrogen cyanide is a colourless gas, with a mild odour. Sodium cyanide would exist in the plant in solution or as white solid briquettes.

Hydrogen cyanide and sodium cyanide are highly toxic by ingestion, inhalation and skin absorption. The cyanides are true noncumulative protophasmic poisons (i.e. they can be detoxified readily). Unless the cyanide is removed, death results through asphyxia. Severe exposure (by inhalation) can cause immediate unconsciousness; this rapid 'knockdown' power, without any irritation or detectable odour to some people, makes hydrogen cyanide more dangerous than other materials of comparable toxicity (e.g. hydrogen suiphide).

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The IDLH concentration of hydrogen cyanide gas is 50 p.p.m. in air, and the TLV in Australia is 5 p.p.m. for an eight hour period. Concentrations of 100-200 p.p.m. for exposures of thirty to sixty minutes can be fatal, and exposure levels of 300 p.p.m. or more are rapidly fatal unless immediate and effective first aid is administered. The human health effects of exposure to hydrogen cyanide are summarized in Table 6.2.

Hydrogen cyanide gas is flammable in the range 6 - 41% volume in air.

Table 6.2 Predicted human health effects of exposure to various concentrations of hydrogen cyanide

P.P.M. Predicted effect

2-5 Odour threshold

20 Causes minor symptoms, including headache and dizziness after several hours

50 Causes disturbances within an hour

- 100 Dangerous for exposures of thirty to sixty minutes

300 Rapidly fatal unless prompt, effective first aid is administered

Natural gas

Natural gas is the other principal feedstock for the proposed plant and would be piped from either the nearby Western Australian Natural Gas Pty Ltd pipeline or the North-West Shelf natural gas pipeline. Methane is the principal component of natural gas (about 87% by volume); other components include hydrocarbons, carbon dioxide and an odourizer for leak detection.

Methane is colourless and odourless and is flammable in the range 5-15% by volume in air. It is toxic only as a simple asphyxiant. It is not explosive when unconfmed, but may explode at high concentrations (90% or more) if confined.

A release of methane may result in the formation of a dense cloud, as sudden reduction in pressure will result in cooling of the gas and surrounding air. Low pressure or relatively slow release will not involve this cooling and, therefore, the gas will be lighter than air and will dilute below flammable concentrations more rapidly.

Carbon monoxide

Carbon monoxide is a colourless, odourless gas with a similar density to air. When inhaled, it combines with haemoglobin in the blood and renders the haemoglobin incapable of carrying oxygen to the tissues, thus producing asphyxia.

- Concentrations of 1,000-1,200 p.p.m. over one hour can be dangerous. Carbon monoxide is eliminated from the lungs when clean air is inhaled.

As carbon monoxide is present only in the hydrogen cyanide reactor products and absorber overhead gas streams at quite low concentrations, it is unlikely to present a

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hazard in the event of a leak, either on or off site. Its presence would, however, increase the toxic severity of hydrogen cyanide if a mixture were released.

6.2.2 RISK ASSESSMENT CRITERIA

Estimated quantified risk levels were compared with risk acceptance criteria as set down by the EPA in Bulletin 278, which considers the risks and hazards of new industrial developments on residential areas.

The EPA guidelines are summarized as follows:

- • The EPA classifies decisions on risk acceptance into three categories. These are:

- a small level of risk which is acceptable to the EPA;

- a middle level of risk which, subject to further evaluation and appropriate actions, may be considered to be acceptable to the EPA;

- a high level of risk which is unacceptable to the EPA and which warrants rejection.

An individual risk level in residential zones of less than one in a million a year is so small as to be acceptable to the EPA.

Where the preliminary risk level in residential zones has been calculated to be in the range of one in a million to ten in a million a year, the EPA would require further evaluation of the risks associated with the project. The EPA may then be prepared to recommend that the project is acceptable, subject to certain planning and technical requirements.

An individual risk level in residential zones exceeding ten in a million a year is so high as to be unacceptable to the EPA.

6.2.3 RESULTS AND ASSESSMENT OF THE PRELIMINARY RISK ANALYSIS

The frequencies and consequences of all potential hazardous events have been combined to produce individual risk contours for the preferred site. The individual risk contours around the site are shown in Figure 6.1.

As noted earlier (Section 6.2.1), the main hazards arise from the loss of containment of pressurized gases or liquids (refrigerated or stored under pressure). The resultant vapour clouds mix with surrounding air and may be dangerous because of the potentially toxic effects from the spreading of the materials and the possibility of igniting a flammable mixture.

Principal hazards encountered in sodium cyanide manufacturing plants include:

releases of ammonia from the supply pipeline, feed tank or the vaporizer (or associated pipework) which contain liquefied ammonia and could produce high flow rates and dense vapour clouds if a serious failure occurred;

ammonia releases downstream of the vaporizer, where the vapour is still under pressure;

releases of natural gas from the supply pipeline, where the gas is at high pressure and could, therefore, lead to the formation of dense vapour clouds;

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Kwinana Nitrogen Company plant

Chlor-alkali CSBP Kwinana plant

works

AGR sodium cyanide plant

Beach Road

Coogee Chemicals

WMC nickel

refinery

Office Road

Legend Contours x 10'6 per year

Note:Contours show individual risk of fatality per million

7f per year.

el

0 1 2km -I I

Scale

Figure 6.1 INDIVIDUAL RISK CONTOURS

hydrogen cyanide releases from the reactor/absorber system;

loss of containment of sodium cyanide leading to contamination and generation of hydrogen cyanide.

Off-site risks

Individual risk from the proposed plant is significantly below 1 x 10-6 (per person per year) in the nearest residential and public access areas. The assessed risk levels, therefore, satisfy the EPA guidelines on risk acceptance.

In-plant risks

Risks within the plant boundary arise mainly from the storage and handling of ammonia and the presence of hydrogen cyanide as a transient product in the process. Established, stringent engineering and operating procedures would be used by Du Pont personnel to minimize the possibility of in-plant exposure to these chemicals.

Domino effects -

A number of hazardous facilities in the adjoining and nearby areas have been examined in order to assess their potential for propagation of an accident (the 'domino effect'). Separation distances between any credible incident and vulnerable sections of the sodium cyanide plant are great enough to ensure that the risks of domino effects are low compared with other risk levels for the installation.

Cumulative risks

The Du Pont facility risk levels decrease to below 10 7 (per person per year) in the immediate vicinity of the plant. This effect zone is between the Kwinana Cumulative Risk Study contours 10 to 10 4, that is, above 10 but not exceeding 10.

Adding the Du Pont levels to the existing cumulative risk levels would result in a small zone above io at the plant site. This is no higher than other existing or proposed chemical plants in the Kwinana Cumulative Risk Study. Risk levels at residential areas should not be affected.

Pipeline recommendations

A liquid ammonia pipeline would be installed to supply the proposed plant. An existing five-pipeline corridor leading to the WMC nickel refinery runs parallel to the railway track, to the west of the proposed plant. Although the risks from these pipelines to the sodium cyanide plant are assessed as low, it is recommended that the total pipeline network in this area be examined critically with a view to rationalizing pipeline routes and improving surface marking and protection where necessary.

Transport

Risks arising from transport of sodium cyanide were not assessed in detail. However, the use of established double-layer packaging techniques and transportation of the packed product within freight containers would minimize the occurrence of cyanide spillage from an accident.

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Abnormal emissions

Events resulting in minor emissions (e.g. during process upset or flare flame-out during start-up) were considered in this study and found to have, at worst, short-term effects at non-harmful levels beyond the plant boundaries.

6.3 SOCIAL IMPACTS

6.3.1 ODOURS

Under normal operating conditions, the atmospheric emissions from the plant would be odourless. As indicated in Section 4.6.3, a short-term odour may be produced during abnormal operating conditions, such as purging of the plant prior to start-up and during the shut-down procedure, but this would only last 3-5 minutes.

6.3.2 NOISE

Noise levels generated during construction and operation would be managed to ensure compliance with the requirements of the Town of Kwinana and the Noise Abatement (Neighbourhood Annoyance) Regulations, 1979 of the Environmental Protection Act, 1986 (as amended).

The noise levels of the major plant components, except perhaps the vacuum pump, would not exceed 85 dBa. The vacuum pump would be effectively isolated from surrounding areas.

Given both the considerable distance between the plant site and the nearest residential areas and the existing general background noise levels emanating from the KIA, noise generated from the site during construction and normal plant operations would not affect neighbouring residential areas.

During construction and operation of the plant, all relevant legislation pertaining to noise levels and workforce safety, including the Occupational Health, Safety and Welfare Act, 1988 and the Construction Safety Act, 1972 (as amended), would be complied with.

6.3.3 TRAFFIC

The increase in traffic in the area caused during construction and by the workforce, plant operations and product transport would be negligible. Patterson Road, Rockingham Road and other major roads in the area cope well with existing traffic and have ample capacity to accommodate further increases in regional traffic movements.

6.3.4 AESTHETICS

The plant (Figure 4.4) would be a compact industrial complex similar to most other sodium cyanide manufacturing plants and would be visually compatible with the immediate surroundings.

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The plant would be most visible from Patterson Road and Rockingham Road. However, landscaping would be undertaken to provide a vegetative screen to visually separate the plant site from these transport routes. Landscaping of the site would also create an attractive working environment.

6.3.5 PUBLIC AMENITY

The Wells Park and Kwinana Beach reserves are important for recreational use associated with public access to the Cockburn Sound. The public amenity of these reserves would not be adversely affected because the landscape, vegetation and other industrial facilities effectively screen the preferred plant site.

Under normal operating conditions, no low-level emissions, odours or noises would emanate from the plant to have any impact on the reserves.

Elsewhere, the visual impact of the plant at the preferred site would be low, particularly in context with the neighbouring industrial facilities. The proposed landscaping and vegetation around the site perimeter would help improve the local amenity.

6.4 IMPACTS ON GROUNDWATER

A recent report on the groundwater resources in the Kwinana area has identified the effects of, and made appropriate recommendations on, excessive groundwater usage and groundwater pollution by industry and non-industrial sources (Kwinana Industries Co-ordinating Committee 1987).

The proponent is aware of the potential risks of water table drawdown and salt water intrusion resulting from excessive groundwater extraction in the KIA. However, process water for the proposed plant would be supplied from Water Authority scheme water, via reticulation mains, and not from local Kwinana groundwater supplies. Therefore, demand for process water would not have any impact on groundwater resources in the Kwinana area.

Although consideration is being given to using small quantities of groundwater for landscaping purposes, the amount and season of any groundwater abstraction would have negligible impact on the groundwater resources. The total amount of water required for landscaping would be the equivalent of about three reticulated average-sized residential lots.

The double lining of the evaporation ponds would ensure that wastewater would not leak into the water table to contaminate groundwater resources. In addition, the space between the two liners would be monitored for cyanide and could be pumped out. Even in the unlikely event of leakage from the evaporation ponds, the cyanide levels of the wastewater would be sufficiently low so as not to cause significant impact on groundwater quality. Monitoring bores around the evaporation ponds would enable the groundwater to be regularly analysed to determine whether any contamination was occuring. The monitoring bores could also be used to recover any wastewater that had leaked from the ponds.

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In the event of leakage, wastewater in the leaking pond would be pumped to any of a number of spare ponds which would normally remain empty. Spare pond capacity would be sufficient to accept wastewater for such period as may be necessary to effect repairs to the lining of the leaking pond. -

6.5 CONSTRUCTION PHASE

The construction phase of the project would extend over a fifteen month period and would require an estimated peak workforce of 110 personnel.

Initial construction activities would involve site earthworks, levelling and compaction, and would utilize equipment common to most industrial site preparation operations.

Plant construction* would involve the erection of buildings and the assembly, using bolted or welded connections, of process components and pipelines manufactured off site.

Noise levels generated during the construction phase would be below the requirements of the EPA and the Department of Occupational Health Safety and Welfare and their respective legislation (Section 6.3.2).

Dust generation would be controlled through application of water from sprinklers or water trucks when necessary.

Increased traffic levels during construction would not cause significant problems, due to the low number of vehicles involved and the capacity of Patterson Road, Rockingham Road and other major roads in the area to accommodate increased traffic.

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Section 7

ENVIRONMENTAL MANAGEMENT AND MONITORING

The proponent has an excellent safety record in regard to the importation and disiribution of sodium cyanide through the Port of Fremantle. In addition, an equally good safety and environmental record has been achieved during the past thirty-five years of operations at the proponent's Memphis sodium cyanide plant. Furthermore, Du Pont received the National Safety Council of Australia Five Star Safety Award for its Girraween facility (Sydney). The proponent has an ongoing commitment to the safety of the workforce, localcommunity and the environment.

7.1 CONSTRUCTION

Environmental management during the construction phase of the plant would commence at the earliest stage in order to develop a facility that would cause minimal impact on the surrounding environment. All contracts would include relevant details on environmental management.

During plant construction, senior personnel would be responsible for supervising the implementation of the plant design measures, which have been designed to take into account the need to protect and conserve the natural vegetation and soil. Where appropriate, established vegetation would be retained. Site clearing would be minimized to that considered necessary for the effective construction and safe operation of the plant. Affected areas would be stabilized as soon as possible.

All site preparation and construction activities would be conducted with the approval of appropriate authorities and in accordance with relevant legislation. All construction materials and practices would be in accordance with the relevant Australian or international codes.

The proponent would take the necessary measures to ensure that noise and dust caused by construction activities were minimized. Appropriate noise suppression devices would be fitted to all machinery likely to exceed statutory noise levels, as required by the relevant legislation. Dust suppression through regular watering would also be implemented.

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7.2 OPERATION

The proponent would make the following commitments to environmental management during operation of the sodium cyanide plant:

Ongoing control of dust would be implemented.

Landscaping of the plant site would be undertaken and would include the establishment of a vegetative screen to improve public amenity.

Noise levels would be in accordance with statutory requirements.

All assembled components and equipment used in the sodium cyanide process would undergo regular preventative maintenance.

All waste products would be disposed of in an environmentally safe manner and in accordance with the requirements of relevant statutory authorities.

The finished product would be transported in a manner approved by all appropriate authorities.

The proponent would participate in the Kwinana Integrated Emergency Management System, which is being developed by the Department of Resources Development to formulate and execute contingency plans in case of an emergency that places the safety of people, property or the Kwinana environment at risk.

7.3 SAFETY FEATURES

The following key safety features would be incorporated into the design and operation of the sodium cyanide plant:

A Hazard and Operability (HAZOP) study would be commissioned to review the design and operating procedures before finalization of the plant design and to identify any potential hazards and operating difficulties. This HAZOP study would be submitted to the EPA for approval.

The amount of hydrogen cyanide in the process system during normal operations would be maintained at a minimum, namely about 1.87 kg.

A secondary gas containment system would be installed around the converter, waste heat boiler and exit gas pipeline to contain the hydrogen cyanide inventory in the event of a credible leak from this equipment. The containment system would allow the process to be shut down, if necessary. The gas containment system would be maintained under a vacuum so that fugitive emissions of hydrogen cyanide do not escape undetected into the atmosphere.

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A surge tank for storing sodium cyanide solution would be provided between the absorber and the evaporator to allow rapid shut-down of the back-end of the plant in the event of a blockage.

Field-installed cyanide detectors would warn of any cyanide build-up.

The production process would be controlled by a Distributive Control System (DCS), which would be operated from a centralized control room, in order to minimize operator contact with the process.

The plant layout (Figure 4.4) would prevent cluttering and permit good, safe operating and maintenance access and flow of the various components of the operation.

All liquid effluent would be treated and tested in batches before reuse in the process or release to the evaporation ponds.

Fire extinguishers, air masks, safety showers, a clearly audible public address system and good lighting would be installed at strategic locations throughout the plant.

A cyanide monitor would be installed in the cooling tower water circulating/purge stream.

An infra-red device would be installed in the flare stack to verify that the pilot flame was in working order. The signal from the infra-red device would be sent to the DCS and would set off an alarm each time the pilot flame was not detected.

An extensive array of instrumentation would be installed to monitor the operations of each major system component of the plant, including:

- sodium hydroxide absorber system - evaporator system - filter/drying system - briquetter/rotary screener system - waste treatment/disposal system.

7.4 TOTAL HAZARD CONTROL PLAN

The Department of Mines (Explosives and Dangerous Goods Division) is currently preparing regulations under the Explosives and Dangerous Goods Act, 1961 (as amended) for the control of storage of dangerous goods in order to protect public safety. The new regulations should be available sometime in 1989.

One aspect of the regulations will be the requirement for major chemical plants to prepare a Total Hazard Control Plan to the satisfaction of the Safety Co-ordinator, Explosives and Dangerous Goods Division. Subject to the final regulations becoming law, the proponent would prepare such a plan for the proposed sodium cyanide plant.

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The Total Hazard Control Plan would cover such issues as risk analysis, auditing, emergency planning and plant modification. Once the new regulations are law, inspectors of the Explosives and Dangerous Goods Division would have powers of inspection and enforcement relevant to the storage of dangerous goods and public safety.

7.5 MONITORING

As described in Section 4.6, liquid wastes would be collected and treated prior to being discharged to sealed evaporation ponds, while gaseous wastes would be flared, where appropriate, and then vented to the atmosphere. A comprehensive monitoring programme would be implemented to determine the effectiveness of general plant operations and waste disposal and to assess the extent of compliance with appropriate standards.

This monitoring programme would involve regular sampling and testing of all plant and works discharges, airborne emissions and ambient air quality, groundwater quality, and noise and dust levels. A series of monitoring devices would be installed throughout the plant site to measure concentrations of atmospheric emissions. Groundwater monitoring bores would be installed around the evaporation ponds to assess whether any wastewater contaminated by cyanide had leaked from the ponds. Noise and dust monitoring would also be conducted and the results reported to the EPA. The specific methodologies for these monitoring programmes would be determined in consultation with the appropriate authorities. Baseline studies would be integral components of these monitoring programmes.

All monitoring would be administered by fully qualified Du Pont personnel or by specialist consultants. All monitoring results would be reported to the EPA at regular intervals or as required by other relevant regulatory authorities, such as the Water Authority, the Department of Mines and the Department of Occupational Health, Safety and Welfare.

7.6 PRODUCT TRANSPORT

As described in Section 4.3.2, the sodium cyanide product would be transported in either bag/box containers or steel fib-bins. The proposed bag/box method by Du Pont is, in essence, a continuation of current practices adopted for the importation and distribution of sodium cyanide through the Port of Fremantle. The polypropylene bag with polyethylene liner has undergone extensive testing and has been shown to withstand a 2 m drop and a one hour water immersion test.

It is generally considered that transportation of solid sodium cyanide is significantly less hazardous that the transportation of liquid sodium cyanide.

The road transport of solid sodium cyanide would be subject to the requirements of the Dangerous Goods (Road Transpért) Regulations, 1983. Safety features such as design of the fib-bins, selection of distribution routes, communications and emergency services

50

would be discussed with the Department of Mines, the Water Authority and other appropriate authorities.

All personnel and customers involved in handling sodium cyanide would be specifically trained and advised of the nature of the goods, the hazards involved and the procedures required to be undertaken in the event of spillage. All carriers would be provided with handbooks, which outline the required practices and emergency procedures, to prevent accidents and to ensure that appropriate action is undertaken should any accidents occur.

Stockpiles of neutralizing agents and emergency response equipment are located throughout Australia. Du Pont's technical representatives regularly carry out training of carriers and customers in various aspects of sodium cyanide safety.

The likelihood of accidents and subsequent spillage of sodium cyanide would be small. In the unlikely event of an accident, it would be most improbable that the freight container would split open to allow spillage of sodium cyanide briquettes.

Each IBC would be labelled with two product labels. These labels would indicate that the IBC contains 'Cyanobrik', the registered Du Pont Trade Name for its sodium cyanide. The label would also detail product information and relevant safety information. In addition, each freight container would have two emergency information panels.

7.7 AUDITING

Regular safety audits would be conducted to monitor the effectiveness of the proponent's commitments to safeguard people, property and the environment, and to ensure that they were being competently executed. Internal audits would be supplemented by external audits to identify means by which even higher safety standards could be achieved.

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Section 8

SUMMARY OF ENVIRONMENTAL MANAGEMENT COMMITMENTS

A number of commitments have been made directly or inferred during the preceeding sections. This section presents a summary of all commitments made by Du Pont. Each Du Pont commitment is numbered to assist reference to specific commitments during the public review and the EPA assessment pericxL

8.1 CONSTRUCTION

8.1.1

All construction materials and practices would be in accordance with all relevant Australian or international codes.

8.1.2

Appropriate noise suppression devices would be fitted to all construction machinery. Noise levels would comply with the requirements of the Department of Occupational Health, Safety and Welfare, as they relate to the construction workforce and the public, and with the requirements of the EPA.

8.1.3

Dust suppression watering practices would be adopted to minimize dust generated during construction activities. Dust levels would comply with the requirements of the Department of Occupational Health, Safety and Welfare and the EPA.

8.1.4

Close liaison would be maintained with local authorities to ensure that noise, dust and traffic impacts were minimized.

8.1.5

Where practicable, buildings would be aesthetically designed and clad in neutral colours so as to be compatible with the surrounding industrial setting and to meet the requirements of the Town of Kwinana.

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8.2 OPERATION

8.2.1

Ongoing control of dust would be implemented to ensure that dust levels did not affect the workforce or the public. Dust levels would be maintained at levels that satisfy the Department of Occupational Health, Safety and Welfare and the EPA.

8.2.2

The noise levels during the operational phase of the project would comply with the Noise Abatement (Neighbourhood Annoyance) Regulations, 1979 of the Environmental Protection Act 1986 (as amended), administered by the EPA, and the Occupational Health, Safety and Welfare Act 1988, administered by the Department of Occupational Health, Safety and Welfare.

8.2.3

The plant site would be attractively landscaped and would include the establishment of a vegetative screen to the satisfaction of the Town of Kwinana. Landscaping would commence as soon as practicable after the completion of the major components of the plant.

8.2.4

The plant would undergo regular preventative maintenance to avoid downtime due to possible component failure.

8.2.5

The plant design would ensure that normal emissions of nitrogen oxides comply with the NHMRC recommended guidelines and with the guidelines adopted by the Victorian EPA.

8.2.6

All non-conforming product produced while the plant undergoes commissioning and precision flow balancing that does not comply with specific performance criteria (relating to colour, concentration, solidity, etc.) would be returned for reprocessing. Contaminated packaging material and equipment would be decontaminated with neutralizing solution and then disposed of at an approved sanitary landfill site.

8.2.7

All waste products would be disposed of in an environmentally safe manner and in accordance with the statutory requirements of the EPA.

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8.2.8

The process and storage areas would be bunded so that runoff and spillages could be collected for treatment. Plant maintenance washings and first flush stormwater, together with process wastewater, would be directed to wastewater treatment tanks before being discharged to on-site evaporation ponds. The evaporation ponds would be made leakproof to prevent any loss of containment of the wastewater. These facilities would be constructed and operated to the satisfaction of the Water Authority and the EPA.

8.2.9

A Total Hazard Control Plan (covering auditing, risk analysis, emergency planning and other issues considered appropriate) would be prepared in accordance with the requirements of the Department of Mines.

8.3 SAFETY FEATURES

8.3.1

A. HAZOP study would be commissioned prior to the finalization of the plant design to review the design and operating procedures, and to identify potential hazards and operating difficulties. Depending on EPA approval, the HAZOP study would be undertaken by Det norske Veritas. Upon completion, the HAZOP study would be submitted to the EPA for approval.

8.3.2

Duplication of all critical equipment and a high level of automation would ensure operational stability.

8.3.3

A number of safety features would be incorporated into the design and operation of the plant to ensure minimal risk to the workforce and public through the utilization of the most up-to-date technology. These would include:

minimization of the amount of hydrogen cyanide in the process system at any one fl ;

installation of a secondary gas containment system around the converter, waste heat boiler and exit gas pipeline to contain the hydrogen cyanide inventory in the event of a credible leak from this equipment. The containment system would allow the process to be shut down, if necessary. The gas containment system would be maintained under a vacuum so that fugitive emissions of hydrogen cyanide do not escape undetected into the atmosphere. The system would be designed to meet EPA guidelines set for achieving gas containment

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installation of a surge tank between the absorber and the evaporator to allow a rapid shut-down of the plant in the event of a blockage;

establishment of a network of field-installed cyanide detectors;

utilization of a DCS operated from a centralized control room to minimize operator contact with the production process;

installation of a cyanide monitor in the cooling tower water circulating/purge streams;

installation of an infra-red device in the flare stack to verify that the pilot flame was always functioning;

installation of a wide range of instrumentation to monitor the operations of each major component of the plant.

8.3.4

The design, construction and operation of the plant would be conducted with the primary objective of maintaining the maximum level of safety to workers and the public. Experienced senior management and operations staff from the proponent's Memphis and Texas City plants would supervise the training of workers in the safe operation of the plant.

8.3.5

Storage of solid sodium cyanide would be in accordance with the Explosives and Dangerous Goods Act, 1961 and would be approved by the Chief Inspector of Explosives and Dangerous Goods (Department of Mines).

8.3.6

A fire protection system would be incorporated in the plant in accordance with the requirements of the plant design and the Western Australia Fire Brigade. All plant personnel would be trained in appropriate fire-fighting techniques.

8.3.7

The proponent would participate in the Kwinana Integrated Emergency Management System, being developed by the Department of Resources Development to formulate and executecontingency plans in case of an emergency.

8.3.8

The method of product transport would comply with all requirements of the Dangerous Goods (Road Transport) Regulations, 1983 and other appropriate legislation administered by the Department of Mines. Personnel involved in sodium cyanide handling and transport would be specifically trained and advised of the nature of the goods, the hazards

5.5

involved and the procedures to be followed in the event of an accident. All product packaging would be clearly labelled and would outline relevant product and safety information as required by the Department of Mines.

8.3.9

All employees would be trained in the safe work practices and emergency procedures appropriate to the operation of the plant and the handling of all associated materials.

8.4 MONITORING AND AUDITING

8.4.1

A comprehensive monitoring programme would be implemented to assess the extent of compliance with the standards and criteria of the Water Authority, the Department of Occupational Health, Safety and Welfare, the EPA and Du Pont. This monitoring programme would include reporting to the relevant authority the results of monitoring all plant discharges, airborne emissions, groundwater quality, and noise and dust levels. These separate monitoring programmes would be prepared and undertaken to the satisfaction of the appropriate authorities. Monitoring would commence as soon as practicable after the commissioning of the plant, although baseline monitoring, where required, would commence prior to the plant commissioning.

8.4.2

Regular safety audits would be conducted to assess the effectiveness of the proponents - commitment to safeguard the public and the environment.

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REFERENCES

Department of Conservation and Environment. 1982. Kwinana air modelling study. Report No. 10. Perth: Department of Conservation and Environment.

Department of Conservation and Environment. 1984. Kwinana: Draft coastal management plan. Bulletin No. 172. Perth: Department of Conservation and Environment.

Du Pont (Australia) Ltd. 1989a. Sodium cyanide plant - site selection study. Prepared by Kinhill Engineers Pty Ltd. May, 1989.

Du Pont (Australia) Ltd. 1989b. Sodium cyanide plant - formal notice to proceed. Prepared by Kinhill Engineers Thy Ltd, May 1989.

Environmental Protection Authority. 1987. Environmental Protection Authority Guidelines - Risks and hazards of industrial developments on residential areas in Western Australia. Bulletin No. 278. Perth: Environmental Protection Authority.

Kwinana Industries Co-ordinating Committee. 1987. Report of the Groundwater Management Group. Perth: Kwinana Industries Co-ordinating Committee. October.

National Health and Medical Research Council. 1986. National guidelines for control of emission of air pollutants from stationary sources. Canberra: Australian Government Publishing Service.

State Planning Commission. 1988. Improvement Plan No. 14. Perth: State Planning Commission.

Technica. 1987. Kwinana cumulative risk analysis. Main report. Prepared for the Department of Resources Development of the Government of Western Australia.

GENERAL ABBREVIATIONS AND ACRONYMS

AGR Australian Gold Reagents Pty Ltd AIS Australian Iron & Steel Pty Ltd Alcoa Alcoa of Australia Ltd

CBH Co-operative Bulk Handling Ltd CSBP CSBP&Farmers Ltd

DCS Distributive Control System Du Pont Du Pont (Australia) Ltd

EPA Environmental Protection Authority

IBC Intermediate Bulk Container JDLH Immediately Dangerous to Life and Health

KIA Kwinana Industrial Area

KTC Kwinana Town Council

NHMRC National Health and Medical Research Council

PER Public Environmental Report PICL Petrochemical Industries Company Ltd

SECWA State Energy Commission of Western Australia SPC State Planning Commission

TDS Total Dissolved Solids TLV Threshold Limit Value

Water Authority Water Authority of Western Australia WMC Western Mining Corporation

APPEND JX A

EPA GUIDELINES

APPENDIX A

hi EPA GUIDELINES

GUIDELINES FOR THE PUBLIC ENVIRONMENTAL REPORT (PER) ON THE PROPOSED DU PONT (AUSTRALIA) LTD SOLID SODIUM CYANIDE PLANT, KWINANA

The guidelines provide a list of topics that should be included within the PER. They are not intended to be exhaustive and the proponent may consider that other topics should also be included in the document.

The PER is intended to be a brief document; its purpose should be explained and the contents should be concise and accurate as well as being readily understood. Specialist information and technical description should be included where it assists in the understanding of the proposal. It may be appropriate to include ancillary or lengthy information in technical appendices. Where specific information has been requested by a GovernmentDepartment or the Local Authority, this should be included in the document.

Al SUMMARY

The PER should contain a brief summary of:

salient features of the proposal;

alternatives considered;

description of receiving environment and analysis of potential impacts and their significance;

environmental monitoring and management programmes, safeguards and commitments;

conclusions.

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/ A2 INTRODUCTION

The PER should include an explanation of the following:

identification of proponents and responsible authorities;

background and objectives of the proposal including development concepts such as access to scheme water, power, transport, labour etc.;

brief details of, and timing of the proposal;

relevant statutory requirements and approvals;

the scope, purpose and structure of the PER.

A3 NEED FOR THE PROPOSAL

- The PER should briefly examine the justification for the proposal. Broad costs and

p benefits of the proposals at local and regional levels should also be briefly discussed.

A4 EVALUATION OF ALTERNATIVES

A discussion of the alternative sites at Kwinana and scales (size) of the proposed operation should be provided. This discussion should clearly explain the rationale for choosing the preferred option.

AS PROPOSED LOCATION

The preferred location is to be described, including:

cadastral and zoning information 1 • topography of the site

separation from other dwellings and properties location of structures to be built on the site

/ • provision of services, including power, gas water and drainage.

A6 PROCESS DESCRIPTION

This section should provide a clear description of each stage of the process. A description of chemicals to be used and the method of storage and handling of these should be included. An indication of the ultimate capacity of the plant should be provided..

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A7 EFFLUENT TREATMENT AND DISPOSAL

This section should provide:

.

a description of the nature of the waste discharge and emissions including volume and composition;

a description of the treatment of the waste and emissions, including the design basis used to determine the size of the treatment process and the rationale for selecting the particular treatment process;

a description of the composition of discharge emission at the final treatment stage

an outline of any backup system.

A8 SITE AND POTENTIAL POLLUTION MANAGEMENT

Having described the waste treatment process it is important to indicate approaches that will be adopted to reduce or prevent problems from arising. For example:

effect of climatic factors on treatment and disposal method;

procedures to be adopted in the event of plant or treatment system breakdown;

procedures used to ensure that the treatment system operates efficiently, both for the present and future;

use cf=iand that is subject to potential impacts including details of buffer zones;

procedures to be adopted in the event of pollution being detected in groundwater or drains.

A9 MONITORING

The waste treatment system will require monitoring to ensure that it is operating efficiently. Specifications for the operation of that system should be assigned.

AlO RISKS AND HAZARDS

Risk and hazard analysis should be carried Out covering the aspects given in the attachment. The proponent is advised to enter into informal discussions with this Authority so that aspects of the analysis can be discussed at an early stage.

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All GUIDELINES

A copy of these guidelines should be included in the document.

Al2 REFERENCES

All references should be listed.

A13 APPENDICES

Where detailed technical or supporting documentation is required, this should be placed in appendices.

A14 COMMITMENTS

A numbered list of all environmental management commitments should be given.

A commitment should include:

who makes the commitment what is the nature of the commitment when will the commitment be carried out, and to whose satisfaction.

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