Story: Rock, limestone and clay
Page 1 – Raw materials
Rock (crushed into aggregate), limestone and clay are the bulk products that dominate New Zealand’s industrial mineral output. Millions of tonnes are dug, blasted and gouged from the earth each year. Since the 1950s they have accounted for between one-third and two-thirds of the value of mined and quarried materials.
Cities and roads
In many places rock, limestone and clay are quarried in massive bulk for general uses. Motorways, roads, bridges, high-rise buildings, pavements, brick houses, the foundations of buildings, and the glass in windows – all are made from quarried materials.
For a small country New Zealand has a great variety of rock formations, which lend themselves to specific uses. The most common rock, greywacke, is suited for road and construction work. Some clay deposits are good for bricks. Certain limestones are ideal for cement – one of the constituents of concrete – and they are mined and quarried the country over. Countless tonnes of concrete are used in urban construction.
Phosphate, sulfur and pumice
Many lesser minerals are also mined or quarried in New Zealand, or have been in the past. These include asbestos, dolomite, pumice, serpentine, sulfur and zeolites. Although at one time small amounts of phosphate were mined, the resources were exhausted, and phosphate is now imported for use in agriculture.