The treasures of the Earth. European Theme Route Mining

Coal from European and American collieries was the universal fuel during the Industrial Revolution. Nonetheless technical inventions in mining played a relatively insignificant role. The main cause was the ongoing abundance of workers. Colliery owners were able to attain higher outputs simply by employing more workers. For the same reason they were able to postpone any improvements to the catastrophic working conditions for a long time.

Thus, for centuries technical developments failed to move on from the Middle Ages, when mining in central Europe had been dominated by silver and gold. Hydraulic power was the main source of energy. In order to remove unwanted water from the pits, large water-wheels were installed both above and below the surface, linked by a clever system of rods with extraction pumps. In order for collieries to remain independent of fluctuations in natural water supplies. coal was also brought to the surface with the help of hydraulic power. The Oker pond in the German Harz region, constructed in 1720, is generally regarded as the first reservoir in Europe.

By this time surface supplies had been exhausted in many places; but digging to greater depths involved the use of ever larger water wheels to drive the pumps. The water column machine, first presented in France in 1731, offered a more efficient solution. Water falling from a great height drove a piston downwards, which was then emptied and rose back up again. However, the decisive innovation was the invention of the steam engine in 1712 by Thomas Newcomen. This was first used to raise pit water in a colliery near Wolverhampton. Other British collieries soon followed. True, Newcomen’s invention needed huge amounts of fuel, but this was practically irrelevant because they were erected directly over the coal supplies. Only a few steam engines went into operation on the continent; in the Belgian mining areas around Liège and Mons. Improvements to Newcomen’s model, and new machines developed by James Watt, made steam technology truly viable around 1800.

By that time coal was the leading mining branch. By 1709 the English had already succeeded in making coke from coal. Around the end of the century the new fuel was in wide use in ironworks. This development rapidly increased the demand for coal on the British Isles. But further improvements in mining were necessary. The use of steam engines make the process more efficient. In addition the old winding cables made of hemp were replaced by wire rope, developed in metal-ore collieries in the Harz mountains in 1834. Lifts were then built into the shafts in British collieries, and wooden pithead scaffolding erected to hold the cable wheel.

New technical developments in ventilation were not put into operation for purely economic reasons. Fresh air was not only needed by the miners underground, it was also necessary to reduce the levels of explosive pit gas. For this reason experiments began with air pumps in British collieries: but colliery owners regarded the investment costs as too high. Many colliers continued to lose their lives as a result of explosions underground, and the risks were made greater by the use of open lighting; candles and oil lamps. In 1815 a scientist by the name of Humphry Davy came up with the first effective safety lamp, whose flame was screened off from the pit gas by an extremely thin wire trellis.

Work underground remained highly dangerous and extremely dangerous to health because of the risk of explosions, roofs collapsing and the bone-breaking labour beneath the surface. Hewers equipped with pick, chisel and hammer were sent along appallingly insecure, badly ventilated galleries which were sometimes so low that they were forced to lie down whilst working. The coal was then loaded into baskets or low wagons, to be drawn by horses over wooden or iron rails – when the galleries were high enough to allow this. If not, people had to push and pull the wagons. In British collieries this work was often done by women and children crawling on all fours. The loads of coal they had to push, weighed up to 250 kg.

Starting in the 19^th century a huge number of mining engines were patented: the Englishman Richard Trevithick invented a rotating steam-driven drill; this was then followed by a piston drill that worked along the same principle as a steam engine. These inventions would have made work underground much easier, were it not for the fact that they were considered too expensive by the colliery owners. Real progress was only made after 1853 with the introduction of compressed-air drives.
Starting in the 1840s massive pithead towers made of quarrystone or redbrick, began to be introduced, mainly on the continent. They were able to bear the loads imposed on the cables, which were being let down to ever greater depths, better than the old wooden constructions. After only a few decades these so-called "Malakoff towers" (named after the fortress in the Crimea), often had to be made higher by the addition of a steel frame. Around the turn of the 20^th century Malakoff towers were replaced completely by even higher steel frames.

About the same time the use of disc-cutting machines – a British innovation – was gradually spreading in the USA and Great Britain. These were equipped with chisels on moving discs, rods or chains to cut a horizontal rift beneath the level of the coal and thereby facilitate hewing. Although this invention lightened miners’ physical labour, it introduced a new stress: noise. Furthermore, the noise of the machines often made it impossible for miners to detect the cracking sound in gallery roofs, that preceded collapses. At first the disc cutters were driven by compressed air, but this was replaced by electricity after people found a way of preventing sparks from intruding into the galleries, and dirt getting into the machines.
Where there were suppliers of soft coal, it proved more advantageous to use a mechanical pick. This was introduced into Belgian coalmines and, after the First World War, into the pits along the Ruhr. Hand labour underground, which had continued almost unchanged since the Middle Ages, was gradually coming to an end.

The coal was increasingly transported from the surface via chutes hanging on chains and shaken with the aid of compressed air. In the 1920s companies began to equip their collieries with electrically-driven conveyor belts. Pit railways with electric locomotives were used along longer stretches. In 1934 a cutter loader was introduced in Great Britain for the first time. This not only cut coal but loaded it in a single working process. In areas where the coal was softer a coal plane was used as an alternative. The first experiments were made in France and the USA and improved to mass production standards by engineers in Westphalia (Germany). The plane was drawn along the surface of the coal, which simultaneously fell on to a moving belt. Finally, fully mechanised coal mining began in the 1940s.