While mining is nothing new, with archeologists finding evidence that the history of mining goes back to the ancient world, it is rare these days to find mines that have continued to produce on a commercial scale. Here are some of the oldest mines still in operation.
1. Khewra salt mine
Dating back as far as the era of Alexander the Great, Khewra is considered the oldest salt mine in the history of mining and second largest salt deposit in the world. The story of its discovery, according to The Times, goes back to circa 320BC, when some of Alexander’s troops stationed in what is now the Punjab Region of Pakistan found their horses licking the stone ground. Out of curiosity, the soldiers copied their equestrian friends, noticing that it tasted rather salty.
Mining salt as a trading commodity did not commence until the Mughal era in the 16th century, and it wasn’t until 1872 that the main tunnel was developed by British mining engineer Dr H Warth, on behalf of the British colonial powers. During the early years of British rule, the salt mine churned out around 28,000t to 30,000t per year of salt.
After gaining independence, the Pakistan Mineral Development Corporation managed the mine, which to this day remains the largest source of salt in the country, producing more than 350,000t of halite (salt mineral) per year, at a purity of around 99%. In total, the mine is predicted to have between 82 million tonnes (mt) and 600mt of salt, depending on the estimate.
The mine consists of nineteen stories, eleven of which are stationed underground, and has a total length of around 40km. Salt from Khewra is known across the world as Himalayan salt and is most recognisable by its pink colour, although it also exists in red, off-white and colourless. In 2003, Khewra produced 385,000t of Himalayan salt and, at this rate, the reserves are expected to last around another 350 years.