 The sand, gravel and rock used for building and road making are called aggregate. They are the most widely used mineral products in the New Zealand, and the most valuable. More than six tonnes are used each year for every person in New Zealand. Aggregates on the West Coast are mostly extracted from river deposits and alluvial terrace deposits. Sand, gravel and rock extraction operations are sited locally because of the high cost of transport.
Washouts and high flood levels on West Coast rivers create a continual demand for riprap for river and coastal protection work. Natural, large river boulders and large quarried blocks of granite, limestone, and lesser amounts of sandstone and schist are extracted from quarries and pits. In order to keep cartage costs to a minimum, a network of quarries is spaced along the main roads.
Selected aggregates and decorative stone are shipped by barge from Greymouth and railed to distribution points in the North Island. |
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base course material used as foundation for sealed and unsealed roads |
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repairing and surfacing roads |
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maintaining railways |
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manufacturing concrete products such as blocks, pipes and paving |
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making bitumen paving |
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drainage and filtration |
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making concrete (concrete consists mainly of aggregate) |
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Aggregate production, quite literally, forms the foundation of any region's infrastructure and future development. |
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| Above picture: Aggregates on the West Coast are mostly extracted from river and alluvial terrace deposits. |
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West Coast Aggregate |
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| Beaches are a source of West Coast aggregate. |
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| A typical river operation. |
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| Aggregates are used as the foundation for the regions roads. |
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| Locally sourced aggregates were used in the construction of the new Grey River rail bridge that has streamlined transport of West Coast coal to Lyttelton. |
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