How Coal mining is done?

Coal miners literally move mountains to feed our insatiable appetite for cheap energy

There’s something brutally simple about coal mining. Take away the monstrous new machinery and ecofriendly marketing jargon and it’s the same dirty, dangerous job it’s always been: ﬁ nd the black stuff and dig it up. The two major schools of coal mining are surface mining and underground mining. To qualify for surface mining, the coal seam must lie within 60 metres of the surface. The miners’ job is to remove all of the ‘overburden’ – the cubic tons of rock, soil and trees above the coal seam – and expose the coal layer for extraction. The main tools of the trade are dynamite and dragline excavators, 2,000-ton behemoths that can move 450 tons of material with one swoop of their massive buckets. Perhaps the most dramatic and controversial surface mining technique is Mountaintop Removal (MTR), in which miners use explosives and heavy machinery to literally knock the top off a mountain – up to 200 metres below the peak – to get at the rich coal beds beneath. Underground mining is decidedly more difﬁ cult and dangerous. In smaller mines, workers still use conventional methods, blasting and digging out large ‘rooms’ supported by thick ‘pillars’ of untouched coal. But that won’t cut it for modern mining operations that regularly remove over 100 megatons (1 million tons) of raw coal each year. The go-to machine of the highvolume coal mine is a continuous miner. This long, low-slung machine rips through coal faces with a wide rotating drum armed with hundreds of drill bits. Each bit is sprayed with a ﬁ ne mist of water, cooling the cutting surface and neutralising coal dust emissions. Using built-in conveyors, the machine rolls the coal off its back, where it’s transported to the surface by haulers or conveyor belts.

Types of coal mine

A closer look at the numerous different methods and mines that are often used to extract coal

Shaft mine

Miners and equipment are transported down vertical shafts hundreds or thousands of metres deep to access fertile coal seams.

Drift mine

The simplest method of underground mining, the coal seam is accessed by digging horizontally into the side of a hill.

Slope mine

For a shallow underground coal seam, miners dig a slanted or ‘sloped’ shaft and remove the coal via long conveyor belts.

Surface mine

In a surface mine (or strip mine), miners remove a horizontal layer of soil and rock called the overburden to expose a coal seam

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