Mining Engineers

The development of mining technology stretches back some 50,000 years to the period when people began digging pits and stripping surface cover in search of stone and flint for tools. Between 8000 and 3000 B.C., the search for quality flint led people to sink shafts and drive galleries into limestone deposits.

By about 1300 B.C., the Egyptians and other Near Eastern peoples were mining copper and gold by driving adits (near-horizontal entry tunnels) into hillsides, then sinking inclined shafts from which they drove extensive galleries. They supported the gallery roofs with pillars of uncut ore or wooden props.

Providing adequate ventilation posed a difficult problem in ancient underground mines. Because of the small dimensions of the passageways, air circulated poorly. All methods of ventilating the mines relied on the natural circulation of air by draft and convection. To assist this process, ancient engineers carefully calculated the number, location, and depth of the shafts. At the great Greek mining complex of Laurion, they sank shafts in pairs and drove parallel galleries from them with frequent crosscuts between galleries to assist airflow. Lighting a fire in one shaft caused a downdraft in the other.

Ancient Roman engineers made further advances in the mining techniques of the Greeks and Egyptians. They mined more ambitiously than the Greeks, sometimes exploiting as many as four levels by means of deep connecting shafts. Careful planning enabled them to drive complicated networks of exploratory galleries at various depths. Buckets of rock and ore could be hoisted up the main shaft by means of a windlass (a horizontal cylinder that is rotated by a crank or belt). Unlike the Greeks and Egyptians, the Romans often worked mines far below groundwater level. Engineers overcame the danger of flooding to some extent by developing effective, if expensive, drainage methods and machinery. Where terrain allowed, they devised an elaborate system of crosscuts to channel off the water. In addition, they adapted Archimedean screws—originally used for crop irrigation—to drain mine workings. A series of inclined screws, each emptying water into a tub emptied by a screw above it, could raise a considerable amount of water in a short time. It took only one man to rotate each screw, which made it perhaps the most efficient application of labor until engineers discovered the advantage of cutting halls large enough for an animal to rotate the screw. By the first century A.D., the Romans had designed water wheels, which greatly increased the height to which water could be raised in mines.

Mining engineering advanced little from Roman times until the 11th century. From this period on, however, basic mining operations such as drainage, ventilation, and hoisting underwent increasing mechanization. In his book De Re Metallica (1556), the German scholar Georgius Agricola presented a detailed description of the devices and practices mining engineers had developed since ancient times. Drainage pumps in particular grew more and more sophisticated. One pump sucked water from mines by the movement of water-wheel-driven pistons.

As mines went deeper, technological problems required new engineering solutions. During the 18th century, engineers developed cheap, reliable steam-powered pumps to raise water in mines. Steam-powered windlasses also came into use. In the 1800s, engineers invented power drills for making shot holes for rock-breaking explosives. This greatly increased the capability to mine hard rock. In coal mines, revolving-wheel cutters—powered by steam, then by compressed air, then by electricity—relieved miners from the dangerous task of undercutting coal seams by hand. As late as the mid-19th century, ore was still being pushed or hauled through mines by people and animals. After 1900, however, electric locomotives, conveyor belts, and large-capacity rubber-tired vehicles came into wide use so that haulage could keep pace with mechanized ore breaking. The development of large, powerful machines also made possible the removal of vast amounts of material from open-pit mines.

Since the late 1980s, the growth of computers and technological innovations has also had an impact on the mining industry. A growing number of mines are becoming more automated and using various technologies, such as robots, unmanned aerial vehicles (drones), advanced explosives, and simulation technology, to improve efficiency and safety in the mining process. As described in a MiningTechnology.com article, "'smart' mines, which incorporate everything from drones to wearables to 3D printing, are becoming more commonplace."