The quest to strike gold has taken miners deeper into the Earth’s crust than ever before. This is because our most valuable metals are now being found at more extreme depths. Rarity, however, isn’t the only factor influencing these metals’ high value; as a mine goes deeper, new hurdles arise, necessitating more specialized and costly equipment.
One of these challenges is bringing the ore to the surface. The TauTona gold mine in South Africa, the deepest mine in the world, is 3.9 km (2.42 miles) down. Despite its impressive depth, however, the facility could only mine a fraction of its estimated 1.7 million ounces of gold ore reserves due to hardware limitations.
Mines are less likely to go any deeper unless their employees and equipment can work effectively in worsening conditions. As they go deeper into the Earth, heat becomes more of a concern. The upper crust alone has a geothermal gradient between 15 and 40 degrees Celsius per kilometre. This can present additional challenges to both men and equipment.
Underground mines need high-volume mine skips that can move vast quantities of raw ore to the surface at once. For instance, in its natural form, gold ore isn’t pure gold at all. Smelting and separation procedures must isolate the gold from impurities and minerals like quartz and silver. If gold mines hope to increase their volume, they need to move more ore.
Mine skips vary by volume moved, depending on the mechanism used. Some skips move over a thousand cubic feet of ore per minute in speeds of abut 600 feet per minute, quite plenty and speedy by mining standards. The collective weight of a greater amount of ore, however, will make the ascent more difficult for the skip, which is why volume is a factor in the design stage.
Manufacturers such as Wabi Iron & Steel Corp create custom ore skips that can withstand the extreme stresses of underground mining. As mines reach deeper in their quest for Earth’s riches, specialized equipment such as these are integral to their success.
(Source: The top ten deepest mines in the world, Mining Technology)