Walton Park Sand
Sand has been taken from the Walton Park area since the early settlement of Dunedin. Blackhead Quarries took over the sand operations in 2004. The present day operations at the Fairfield site imports raw material from various locations to process. The sand is washed and/or dried to produce high grade end products for markets throughout New Zealand. Up to 60,000 tonnes of sand are mined and processed by these operations each year.
This is very high grade yellow sand mined in the Fairfield area. The Walton Park sand is washed and dried then screened to small fractions. This material is a very high grade single sized product. It is used for drilling sand and industrial flooring.
Wash Plant
Up to 5,000 tonnes of raw materials are stockpiled on site prior to the washing plant. A 14 tonne loader is used to feed the bin. The sand is then screened to remove any clay or large stones. From there the material passes through a scrubber and over another screen which takes out the golden peebles. The final stage in the process has the material pumped through a cyclone to take out the fines with the final product drained and stockpiled.
Drying Plant
The dry sand plant is all inside and starts with washed sand being put through a drum dryer with any large particles screened off before the product goes to indoor stockpiles for cooling. This sand is either sold in bulk or taken on for further processing through a Morgensen screening plant. This processed sand is then bagged into either 1 tonne or 25kg bags depending on customer requirements.
All the extraction and processing operations have quality and safety systems externally audited to ISO 9001 and NZS 4801 respectively. These systems help ensure quality products and a healthy workforce.
Environment
With sand taken from an array of sites there are different environmental concerns. Ferny Hill and Walton Park require strict controls of water movement across the site, dust management and control of overburden removal and rehabilitation of mined out areas. The Kuri Beach resource requires a respect for the whole beach environment and the same applies to the dune sand deposits. The washing plant uses large amounts of water which is extracted and deposited on site with a comprehensive series of ponds. There is an air management system in place over all the drying plant to control airborne dust and any stray dust particles.