Almost all 19th-century mining was underground, and colonial men, used to a footloose, independent life, did not easily adjust to underground mining. Those who took up mining in New Zealand tended to be immigrants – at first from the copper- and tin-mining areas of Cornwall and Devon, and then from coal-mining areas in Northumberland, Durham, Yorkshire and Wales. Many brought with them traditions of trade unionism and Methodism. In the early 20th century a number came from the Australian fields, while the expansion of the Waikato fields after the First World War attracted Māori workers into the mines.
Given their backgrounds, it is unsurprising that the early miners used traditional techniques to extract coal. At first this involved picks and shovels. Seams of coal were mined using the ‘bord and pillar’ method – sections were extracted leaving pillars to hold up the roof, then the pillars were partly removed as the miners retreated towards the entrance.
Mechanisation was slowly introduced from the 1900s. Because mining conditions varied so much between coalfields, no one method was useful everywhere. Compressed-air machinery was used to varying degrees. In the later 20th century, high-pressure water-jet cutting was introduced in some West Coast mines. Coal flowed out in water directly from the face, whereas in conventional mining the coal was drilled, blasted, and loaded into tubs or carried on conveyors.
Got it easy
Tommy Pinn started at the Strongman mine in 1941 and retired 46 years later. In 2003, as the mine finally closed, he noted: ‘Boy they’ve got a good number today, all the miner was doing was sitting behind this big machine pushing buttons, in a matter of minutes 2 metres of coal was cut from a place about 15 feet wide by 10 feet. It would take the best part of two or more days to do that in my time, after you did all the timbering, boring and blasting. Then we had to shovel the whole lot all out by hand!’ 1
Besides the hewers at the coal face, there were many other workers underground – those hauling the coal, pumping water, looking after the ventilation, and trimming the lamps. In the 19th century their conditions of work were often appalling. At first, the same areas were used as eating places and latrines. When excrement cans were provided, they were often placed in old workings where toxic firedamp (methane gas from coal) collected. Most mines before the First World War did not provide bathhouses and it was a long, dirty and often wet walk back home. Above ground, men worked as loaders, screening the coal, and as blacksmiths, carpenters and engine men.
On the West Coast, work was erratic because the river ports were often closed by bad weather. On many days the mines did not open.
Modern mining is increasingly opencast, and by the early 2000s only two major underground mines remained (Huntly East and Spring Creek). The last underground mine in New Zealand closed in 2017.
Opencast mining involves removing overburden from the coal seam using motor scrapers or by blasting harder cover rocks. The debris is removed by heavy equipment, including draglines, shovels, bulldozers, front-end loaders and trucks. Opencast mining generally recovers 90% or more of the coal seam, compared with 25% to 75% from underground mining. The deepest opencast mine in New Zealand is at Rotowaro.
From the 1990s it became normal practice to restore mine sites as near as possible to their pre-mining state.