Holcim (New Zealand) Ltd continues to provide information to the Oamaru community relating to its proposed Weston option cement plant, as technical investigations being carried out in preparation for lodging resource consents advance to the stage where accurate and relevant information can be provided.
In May this year Holcim announced its intentions to work towards making resource consent applications, and since then has been going through a process where it has been gathering the necessary information to support those applications. The company is dependent on its independent advisors providing their reports so that information can then be provided to the community. The various reports that contain that information and assess effects on the environment are only now being finalised.
"The timing of our information gathering and consultation has remained consistent throughout the process to date", said Paul Commons, Holcim New Zealand General Manager, Strategy and Development. "We are communicating in the timeframe we had always indicated and are not able to accelerate that process. The final reports in some technical areas are simply not completed and when they are, will be released to stakeholders."
Holcim New Zealand has today provided answers to a number of questions recently received from the Waiareka Valley Preservation Society relating to fuels and raw materials, air quality monitoring, and rain effects, which it is able to provide in advance of the technical reports from independent advisors (This document follows at end of media release).
In addition the company has offered to arrange a meeting between air quality advisors that are advising Holcim and those who are advising the Society on air quality matters. It has also offered a meeting with its technical advisor on health issues to discuss questions the Society has raised.
"Consultation is a two-way process, needing openness and respect on both sides. We find it helpful to meet and discuss questions any members of the community may have, so that we ensure we address these", said Paul Commons.
Holcim has asked the Society for clarification on two questions it has raised, including that relating to its request to carry out its own sampling of limestone, coal and tuff that would be used at the plant.
"Analyses of limestone, coal and tuff have been carried out independently of Holcim, and we have offered to provide a copy of the certification and accreditation of the relevant laboratories so that the Society can be assured of the credibility of this information," said Paul Commons.
"We are keen to discuss with anyone their questions and comments about the project, and will continue to provide information to the Oamaru community as it becomes available."
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Answering Your Questions
Information to address questions
relating to the proposed Weston Option cement plant
Ensuring accurate and relevant information
Holcim (New Zealand) Ltd has consulted and communicated widely since May 2006, when it first announced that a cement plant at Weston was one of the options it was considering to ensure cement supply to meet local demand. Holcim will continue to communicate and consult to receive feedback from community members, to answer questions and to make ensure local people have accurate and relevant information.
Answering your questions
This document continues our practice of providing answers to questions about aspects of the Weston option cement plant. It provides information where this is available, and indicates some areas where completion of technical investigations is required before information can be provided. There is a large amount of very technical data which can be made available as it is finalised and verified.
Explaining fuels and raw materials
The proposed Weston option cement plant would have a design capacity of 2400 tonnes of clinker per day. (Clinker is an intermediate product in the cement making process). The primary fuel source for running the plant's kiln would be coal quarried at Ngapara. This would be supplemented by used oil.
Ngapara coal is classified as a lignite. Coal is a combustible, stratified organic sedimentary rock composed of altered and/or decomposed and reconstituted plant remains. Lignite has been less lithified (ie. subject to heat and pressure) than other forms of coal (known as black coal), with consequently higher moisture and lower calorific value.
Coal in the cement making process provides both heat energy and mineral components that form part of the cement product. To reach the design capacity production of clinker, approximately 450 tonnes of coal per day would be required, taking into account the expected used oil supply rate.
Used oil would supplement coal as a fuel for clinker production, and would be used in accordance with all applicable regulations including the National Environment Standards set by the Ministry for the Environment under the Resource Management Act. Used oil has provided a fuel source at Westport Works for the last ten years, reducing the use of non-renewable coal. The oil is collected from around New Zealand using the Ministry for the Environment-endorsed Used Oil Recovery Programme. Making clinker requires very high temperatures, compared with the much lower temperatures of ordinary combustion. These high temperatures - up to 2100 degrees Celsius - provide an environmentally secure way to use used oil. Consent applications being lodged in 2007 for a plant at Weston do not include any other alternative fuels.
Limestone is the primary raw material used to make cement, and is a sedimentary rock composed almost entirely of calcium carbonate. Limestone would be quarried from Holcim land adjacent to the proposed plant site at Weston by dozing, ripping and excavation (blasting won't be necessary). The limestone at Weston (known as the Ototara Limestone) is an organic limestone consisting of the skeletal remains of bryozoa (colonies of aquatic invertebrates) and, in places, pebbles of volcanic origin. To achieve design capacity of 2400 tonnes of clinker per day, approximately 3,300 tonnes per day of limestone would be needed.
Meeting Air Quality Standards
Holcim New Zealand is committed to operating within all air quality requirements set by the Otago Regional Council and National Environment Standards for Air Quality. These air quality standards are put in place to protect the health and well-being of people, animals, and plants.
Holcim's target for the proposed Weston option cement plant is to achieve a stack emission level for nitrogen oxides of less than 500mg/Nm3. While it is likely that Holcim's target can be achieved without the use of selective non-catalytic reduction technology (SNCR), Holcim has nevertheless chosen to use SNCR, regarded as a best available technique (BAT) within the cement industry, to ensure this target is achieved. This would result in ground level concentrations of nitrogen oxides well below the criteria set out in the National Environment Standards.
For sulphur oxides, Holcim's target for the proposed Weston option cement plant is to achieve a stack emission level of less than 400mg/Nm3. The plant design incorporates a kiln preheater, precalciner system and closed raw mill which together act as an effective sulphur scrubber (to clean exhaust gases). This would result in ground level concentrations of sulphur oxides within the criteria set out in the National Environment Standards.
Best available techniques in continuous monitoring systems would be used to monitor emissions of fine particulate matter (PM10 PM2.5). PM2.5 is extremely fine dust which is less than 2.5 microns in diameter (1 micron equals 1/1000th of a milimetre). Ground level concentrations of both PM2.5 and PM10 would be well within relevant standards.
Modelling of ground level concentrations for trace metals and compounds is still being completed, however initial results indicate that the emissions would be significantly below air quality standards set to protect the community's health and well-being. Our existing cement plant operations operate within international Holcim limits for trace metals, however as potential metal emissions are related to the raw materials used and to the technology used, comparison with existing Holcim operations is not useful. Once modelling is completed and verified in the New Year further information relating to trace metals and compounds for the Weston option will be made available.
Levels of dioxins and furans emitted would be at extremely low levels, again well below the Ministry for the Environment's Ambient Air Quality guidelines.
The proposed Weston cement plant would not produce a by-product known as cement kiln dust. One of the reasons why Weston is being considered as a potential cement plant location is because the nature of local raw materials ensures that no cement kiln dust would be produced.
As well as ensuring the welfare of people in the community, Holcim New Zealand has checked to ensure that Oamaru's heritage limestone buildings will be safeguarded. Rain in New Zealand normally has a pH level of between 4.8 and 6, as a result of rain absorbing compounds in the atmosphere. These compounds are both naturally occurring, such as chlorides (from the sea) or carbon dioxide (from plants decomposing), and man made such as nitrates and sulphates (eg.cars, home fires). Surface erosion as a result of this effect is about 2mm per 100 years on an unprotected limestone building (based on international research). Local pH in Oamaru rain is 5.5. Based on the available data the maximum change to pH levels as a result of the proposed Weston option cement plant (looking at a worst case scenario) would be to lower pH from 5.50 to 5.47, causing no measurable change in surface erosion to buildings. Other factors that can cause surface erosion of stone buildings and structures include wind erosion, flaking, freezing and thawing cycles, and biological growths such as lichen and mosses and bacteria.
Further Questions Welcomed
Holcim New Zealand is pleased to have the opportunity to help members of the local community gain a greater understanding about the proposed Weston Option cement plant.
We welcome further questions and appreciate the willingness of the community to listen to our answers and to discuss the project with us.