1.1 Mining on the West Coast and in Southland[1]
Coal and gold mining have a rich history on the West Coast of the
South Island
and in Southland, with mining commencing around the mid-1860s. Today, the West Coast and Southland are the main coal mining areas in the South Island, and the third largest hard-rock gold mine in
New Zealand
is at Reefton on the West Coast. Active gold mining and exploration occur on the West Coast, but there is less such activity in Southland. The scale and number of mining operations have expanded and declined several times over the years as demand for commodities changes. Mining of deposits that have marginal profitability can stop and restart depending on commodity prices. Up until the 1970s mining was conducted with little regulation of the impact on downstream water quality or ecosystems. Several historical mine workings occur throughout the landscape, particularly on the West Coast, with numerous historical mining workings causing significant impacts on downstream water quality.
1.1.1 Coal mining
On the West Coast mining occurs in 13 coalfields of various sizes mostly between Greymouth and Seddonville (c. 40 km north of
Westport
). The most productive of these are the Buller, Greymouth,
Pike
River
, Reefton and Garvey Creek coalfields. Of the 983 million tonnes (megatonnes; Mt) of in-ground coal in the region, over three-quarters of recoverable reserves are in the Greymouth (mostly underground) and Buller (mostly opencast) coalfields. Rocks mined for coal belong primarily to either the Brunner or Paparoa sedimentary sequences and these sequences are found in most of the coalfields. Both Paparoa and Brunner sedimentary sequences contain coal seams up to 20 m thick.
This coal is primarily bituminous and as a result almost all of the coal mined on the West Coast is exported for steel production. Currently about 2 Mt are mined on the West Coast each year, which accounts for about half of New Zealand’s annual coal production. However, there is scope for this to grow over the next few years as new mines start to produce.
In Southland, coal and lignite are currently mined from the Ohai coalfield and the Eastern Southland lignite deposits, respectively. The Ohai coalfield has relatively small recoverable resources of about 50 Mt. In contrast, the eastern Southland lignite fields are
New Zealand
’s biggest fossil fuel energy resource and contain over six billion tonnes (gigatonnes, Gt) of lignite, most of which could be opencast mined.
Current annual production from Southland is about 300 000 t and this coal and lignite is mostly used for domestic industry. However, there is potential for lignite mining in Southland to grow by more than an order of magnitude if economic conditions are favourable.
1.1.2 Gold mining
Alluvial gold mining on the West Coast commenced around 1864 with the discovery of payable gold in Greenstone Creek, a tributary of the
Taramakau
River
. Payable alluvial gold was also dug from
Coal
Island
in Preservation Inlet, Fiordland, in the 1880s, although by 1904 few miners remained.
In Southland, by the 1860s black sand on the beach at Orepuki, near Riverton, was found to yield very fine gold and platinum. Sluice mining soon recovered gold from the coastal terraces. Other finds at nearby Round Hill proved even richer, and extensive sluicing operations continued until the 1950s. Gold in Southland was also found in the Waiau catchment at Blackmount and the Mataura catchment around Waimumu, Waikaia and Nokomai.
On the West Coast, hard-rock gold mining commenced in 1867 with underground mining of quartz at Reefton. Between 1870 and 1951, 84 Reefton mines produced 67 t of gold. Underground gold mining on the West Coast ceased with the closure of the Waiuta mine (south of Reefton) in 1951. Mining at Reefton recommenced in 2007 with the opening of a major opencast gold mine (Globe-Progress).
