A new cement plant at Weston would meet all regional and national air quality standards, if it is built by Holcim (New Zealand) Ltd. That undertaking is given in the latest information sheet on the cement plant and its associated quarries being investigated by Holcim.
Building a US$200m cement plant and opening quarries for limestone, sand and coal is one of four options being considered by Holcim to meet a growing demand for cement. Other options are redeveloping Holcim’s Westport plant, building a new cement works in the King Country or importing cement.
Holcim plans to apply for resource consents for the Weston proposal early next year and will decide no earlier than 2008 whether to proceed with the plant. As part of the resource consents process, Holcim is releasing information sheets to the community for comment and feedback.
Its air information sheet outlines air quality standards, options for air quality control and includes predicted discharges from the operation of the cement plant and quarries. Holcim said there may be dust generated while sites were being cleared for the cement plant and limestone quarry west of Weston, the coal pit at Ngapara and sand pit at Windsor.
Fine particulates and nitrogen dioxide may be discharged from the main stack at the cement plant. Sulphur dioxide would be generated by the fuel (coal and oil) used at the plant, along with small quantities of carbon dioxide. Other discharges in small quantities could include metals and volatile organic compounds from the cement production. Water vapour above the main stack could occur in some climatic conditions.
Examples of air quality control measures include.-
• Dust control during site clearance and construction by watering and replanting cleared areas wherever possible;
• Dust control methods within the quarries and pits by water carts and slow vehicle speeds;
• Using bag filters to capture particulate discharges from the cement plant and controlling discharges from stockpiles by screening and watering where necessary;
• The main stack would be 100m high and the cement mill stack 55m high to allow for proper dispersion of any discharges not captured by filters;
• Selected equipment to minimise the generation of nitrogen dioxide;
• Binding sulphur dioxide into the clinker, an intermediate product in cement production;
• A voluntary agreement with the Government to reduce carbon dioxide emissions by 20% by 2010.
• Holcim would also undertake comprehensive monitoring to ensure standards were being met.