No economic mineral deposits are known in the Southern Alps, but the low-grade schists west of the main divide contain quartz veins from which the gold deposits of Westland are thought to be derived. The quartz veins themselves are poor in gold but the concentrating action of rivers and sea has produced rich leads now very largely worked out. Greywacke gravels derived from the alps and foothills are the main source of road metal and concrete aggregate in the South Island.
The main economic product of the Alps is the waterpower produced by the heavy precipitation throughout the high country. This is at present exploited only by power stations on the Waitaki River and at Lake Coleridge. (Others on the Waitaki River and its major tributaries are in course of construction.) Several other rivers, though difficult to exploit, are potential hydro-electrical producers.
by Alan Copland Beck, M.SC., New Zealand Geological Survey, Christchurch.