Most Coromandel gold was locked up in quartz reefs, unlike in the South Island where a lot of gold was alluvial – found in rivers and easily recoverable by small groups of miners. Extraction of quartz gold required machinery and capital available only to gold-mining companies.
Extracting gold from quartz reefs
The hard quartz had to be pounded into a powder by stamper batteries consisting of rows of iron hammers or stamps. Then water was added to the powder to create a slurry, followed by mercury to catch the gold. This method worked well with high-grade quartz, but not where the gold was fine or mixed with sulphides.
The cyanide process, introduced in the 1890s, largely solved the problems of the mercury process, enabling the recovery of high levels of gold and silver from all grades of ore.
The discovery of gold at Coromandel Harbour in 1852 triggered a rush from Auckland, but diggers found little alluvial gold and the rush quickly petered out. The goldfield had little success until the arrival of well-financed companies with quartz-crushing equipment in the late 1860s. New gold discoveries in the wider area sustained the industry until the end of the century.
The greatest strike of all was the Caledonian mine. On one occasion blasting brought down two tons of ore, which yielded 25,000 ounces (709 kilograms) of bullion. However, generally great toil was for little return.
The Thames goldfield made a slow start in 1867, as once again only quartz gold was found. Then the discovery of several gold-rich reefs created a town overnight and New Zealand’s first stock-market boom. Output steadily declined from 1871. About 75% of the bullion (gold and silver) came from ‘strikes’, that is, gold-rich pockets in quartz reefs, which were found in an area of less than 80 hectares.
Thames’s population was 15,000 in 1868, 8,000 in 1874, 6,000 in 1881, 4,500 in 1896, and 3,750 in 1906.
In its heyday Thames was a place of noise, smoke and mud. Day and night the ground trembled from the shock of stamps, waterwheels creaked and chimneys belched smoke. Poorly drained roads became seas of mud. All the trees close to the town were felled for houses and mine props. The scarred landscape pierced by countless tunnels resembled an immense rabbit warren.
Gold versus silver
Around 80% of the bullion extracted from the Coromandel between 1860 and 1950 was silver – but it sold at an average of two shillings an ounce, compared with 80 shillings an ounce for gold.
The Ōhinemuri goldfield was opened in 1875, but took off only in the 1890s when a new cyanide process made the working of low-grade ores profitable. The Crown mine operated until 1928 and the Talisman mine until 1939.
Gold was discovered at Martha hill, Waihī, in 1878, but ore grades were low. The cyanide process, which made mining profitable, turned Waihī into one of the great gold-mining districts of the world by 1900. Waihī was a bustling town of 5,600 residents in 1906, overtaking Thames and overshadowing Hamilton’s 2,000. After the exhaustion of near-surface reserves, deep shafts were sunk down to 570 metres.
Ore production peaked in 1909 at 400,000 tons, and it stayed around 200,000 tons per year in the 1920s and 1930s. Low ore grades, labour shortages and a low international gold price forced closure of the Martha mine in 1952. It had produced more than twice the gold and silver of all the other New Zealand goldfields put together, and accounted for around 60% of all the gold produced in the Coromandel.
The miner’s lot
Miners’ work was hard and risky, and usually had low returns. They pursued gold-bearing reefs with picks, chisels, rock drills and explosives. They drove adits (horizontal tunnels), sank shafts (vertical holes) and excavated areas of gold-bearing quartz. Then they wheelbarrowed, railed or hoisted the quartz and waste rock to the surface – danger always close at hand.
At Waihī six miners died in the pit in 1910. Miners grew increasingly unhappy with the arbitration system as a means of improving terms and conditions of employment. In 1912 they went on strike, angered by the mining company’s recognition of a separate union for train drivers. For six months Waihī was locked in an industrial conflict that divided the nation. A miner, Fred Evans, was beaten to death before order and normality were restored.
Return to mining
In the 2000s the Coromandel Peninsula was once more a gold-mining region. The Martha mine reopened in 1987, the Favona mine in Waihī opened in 2006 and the Golden Cross mine operated from 1991 to 1998. In 2010 the government unsuccessfully advocated opening Crown lands on the peninsula to mineral prospecting – including small areas with high conservation value.