Khewra Salt Mine

Salt mine in Khewra, Pakistan

The Khewra Salt Mine (Punjabi, ), also known as Mayo Salt Mine, is the world's second largest salt mine, located in Khewra, Punjab, Pakistan. The mine is in the Salt Range of the Potohar plateau, which rises from the Indus plain of the Punjab. The main tunnel at ground level was developed by H. Warth, a mining engineer, in 1872 during British rule. After independence, the BMR took possession until 1956 and then PIDC owned the mines till 1965. After India Pakistan war in 1965, the WPIDC took over the administration of salt mines and in 1974, the Pakistan Mineral Development Corporation took over the mine, which still remains the largest source of salt in the country, producing more than 350,000 tons per annum of about 99% pure halite. Palynomorphs (organic microfossils) have been used to make inferences about the ages of the Salt Range Formation and its salt layers that are exposed within the Khewra Salt Mine. For example, while working with Geological Survey of India in the 1930s and 1940s, Birbal Sahni reported finding evidence of angiosperms, gymnosperms, and insects inside the mine which he regarded as originating from the Eocene period. However, on the basis of additional geologic data, later research has concluded that these palynomorphs were contaminants.

The Khewra Salt Mine is also known as Mayo Salt Mine, in honour of Lord Mayo, who visited it as Viceroy of India. The salt reserves at Khewra were discovered when Alexander the Great crossed the Jhelum and Mianwali region during his Indian campaign. The mine was discovered, however, not by Alexander, nor by his allies, but by his army's horses, when they were found licking the stones. Ailing horses of his army also recovered after licking the rock salt stones. On the downfall of the Mughal empire, the mine was taken over by Sikhs. Hari Singh Nalwa, the Sikh Commander in Chief, shared the management of the Salt Range with Gulab Singh, the Raja of Jammu. The former controlled the Warcha mine, while the latter held Khewra. The salt quarried during Sikh rule was both eaten and used as a source of revenue. In 1872, some time after they had taken over the Sikhs' territory, the British developed the mine further.

Khewra Salt Mine is in Pind Dadan Khan Tehsil of Jhelum District. About from Islamabad and Lahore, it is accessed via the M 2 Motorway, about off the Lilla interchange while going towards Pind Dadan Khan on the Lilla road. Khewra mine is about above sea level to over 600 million tons. In raw form it contains negligible amounts of Calcium, Magnesium, Potassium sulfates, and moisture; it also contains iron, zinc, copper, manganese, chromium, and lead as trace elements. Salt from Khewra, also known as Khewra salt, is red, pink, off white or transparent. In the early years of British rule, the Khewra mine produced about 28,000 to 30,000 tons per annum; it increased to about 187,400 tons per annum for the five fiscal years ending 194647 and to 136,824 tons for the two years ending 194950 with the systematic working introduced by H. Warth. The mine's output was reported in 2003 to be 385,000 tons of salt per annum, which amounts to almost half of Pakistan's total production of rock salt. At that rate of output, the tunnel would be expected to last for another 350 years. Quarrying is done using the room and pillar method, mining only half of the salt and leaving the remaining half to support what is above. The temperature inside the mine remains about throughout the year. Khewra salt is Pakistan's best known rock salt. Salt from Khewra mine is also used to make decorative items like lamps, vases, ashtrays and statues, which are exported to the United States, India and many European countries. The use of rock salt to make artistic and decorative items started during the Mughal era, when many craftsman made tableware and decorations from it. Warth introduced the use of a lathe to cut out art pieces from the rock salt, as he found it similar to gypsum in physical characteristics. In 2008 the Government of Pakistan decided to sell off seventeen profitable organisations including Khewra salt mines, but the plan was shelved. The mine is now operated by the Pakistan Mineral Development Corporation, a government department. There are numerous pools of salty water inside. The Badshahi Masjid was built in the mining tunnels with multi coloured salt bricks about fifty years ago. Other artistic carvings in the mine include a replica of Minar e Pakistan, a statue of Allama Iqbal, an accumulation of crystals that form the name of Muhammad in Urdu script, a model of the Great Wall of China and another of the Mall Road of Murree. for the treatment of asthma and other respiratory diseases using salt therapy. The "Visit Pakistan Year 2007" event included a train safari visit of Khewra Salt Mine. In February 2011 Pakistan Railways started operating special trains for tourists from Lahore and Rawalpindi to Khewra. For this purpose the railway station of Khewra was refurbished with the help of a private firm. Other visitor attractions in the mine include the 75 meter high (245 foot high) Assembly Hall; Pul Saraat, a salt bridge with no pillars over a 25 meter deep (80 foot deep) brine pond; Sheesh Mahal (Palace of Mirrors), where salt crystals are light pink; and a café. The institute conducts mine surveys, organises mining related courses for the miners and has establishes the Khewra Model High School and the Khewra Women College. The water available to the residents of Khewra had been polluted by salt, coal and other nearby mining activity. This case is internationally recognised as important with regard to the relationship between humanity and the environment. In 2003, while the Government of Pakistan was looking for ways to increase the country's strategic store of oil to 90 days, the PMDC put forward a proposal to use the Khewra mines to store strategic oil reserves. Scientific reports confirmed the feasibility of this proposal, but it was turned down.

In 2010, during torrential rain all over Pakistan, water from a nearby nullah entered the mine, reaching a depth of 2 feet (1 m) and blocking the exits, after which the mine was closed. It was subsequently reopened and remains open.