Page 2 – The Blackwater mine

Joseph Divis' photos of Waiuta - click on thumbnails to see full images.

Mining for gold

A small prospecting group discovered a gold-bearing quartz reef near the upper reaches of Blackwater Creek, a tributary of the Grey River, on 9 November 1905. As the discovery was made on King Edward VII's birthday, it was loyally named the Birthday Reef. The rights were subsequently purchased by Consolidated Goldfields (NZ) Ltd, a large British-owned company that dominated the Reefton quartz mining industry. The company invested heavily to develop a mine and processing plant as well as a town for their workers

It was money well spent. The almost vertical quartz reef was mined to a depth of almost 900 metres (275 m below sea level) over the next 45 years. Although it was a narrow reef (or vein), generally less than a metre wide, the gold values consistently remained high. It was one of the most regular and persistent gold reefs ever recorded anywhere in the world.

Going underground

The miner's job was to extract the gold-bearing quartz. Shot holes were drilled in the quartz reef, and packed with explosives so that the hard quartz could be broken into small enough pieces to be shovelled into wagons. Because the reef was so narrow, miners were always working in a confined space. It was dusty work, and quartz dust was notorious for causing silicosis or miners' phthisis – a chronic and often fatal lung condition. A miner endangered his health every day he spent underground. While the hazards of quartz dust could be reduced by spraying water, the mine was always a dangerous place to work. Many miners died young.

Everything, including the miners themselves, was taken in and out of the mine in cages, up and down the main shaft. All the gold-bearing quartz ore was trucked to the main shaft, to be loaded in cages and transported to the surface. This was a bottleneck for transporting the ore. As far as possible it was essential to transport only gold-bearing material, while making sure that none got left behind, and this was part of the skill of an experienced miner.

Above the ground

The ore was transported on a tramway (and later on an aerial ropeway) to the processing plant on the side of the Snowy River valley. The steep site was chosen deliberately so that the ore could be moved through the various recovery processes by gravity, aided by high-pressure water.

Private gold

Although the gold was usually not visible, flakes could be seen in parts of the reef. Miners would sometimes collect pieces of gold-bearing quartz, smuggle it out of the mine in their crib boxes, and extract the gold in the weekend. This was risky, though, as the company carried out random checks on people leaving the mine.

When the plant opened in 1908, it boasted state-of-the-art technology. With minor refinements, this was used for the next 30 years. Although a new processing plant was built and a new shaft sunk in the 1930s, Joseph Divis' images show the mine as it was in the 1920s and early 1930s.

It was not easy to recover all the gold. Tiny particles, mainly too small to be seen by the naked eye, were dispersed through the hard quartz. In order to recover the gold, the quartz needed to be crushed to a powder in stamper batteries, and then passed in watery slurry over copper amalgamating plates coated with mercury. The remaining powdered rock was treated with cyanide to increase the yield of gold. The final stage was to heat the concentrate in a furnace, and pour the melted bullion (gold, with a little silver and other impurities) into bars.

How to cite this page

'The Blackwater mine', URL: https://nzhistory.govt.nz/culture/waiuta/blackwater-mine, (Ministry for Culture and Heritage), updated 16-Jun-2015