A reflection

By Dinesh L. Gmeiner

The Salt Range is a three hundred kilometre long low mountain range between the two rivers Indus and Jelam in the north of the Pakistani province of Punjab. In the salt mountains, salt is extracted by mining in the so-called chamber mining method using blasting technology. The piles themselves are loaded onto trailers and lorries by hand.

Contents

1.  The salt mountains                   
2.  Salt extraction in the salt mountains                 
3.  Salt building materials

The salt mountains

The Salt Mountains (also known as the Salt Range or Salt Mountains) are a low mountain range averaging almost seven hundred metres above sea level and about three hundred kilometres in length between the two rivers Indus and Jelam in the north of the Pakistani province of Punjab. The Jelam is the westernmost of the five major rivers, all of whose waters eventually flow into the Indus.

The salt mountains take their name from the extremely high quality rock salt deposits that are up to several hundred metres thick. The purity of the salt varies slightly depending on the location and mine, but is always very high: in Khewra, for example, the average salt content is 98 per cent, in Kalabagh 96 and in Warcha 98. The raw salt can be sold as table salt immediately after crushing. Due to its high purity, however, it can also be easily analysed. For this reason and because of its beauty, red mountain salt is particularly suitable for the production of salt products to be backlit, such as salt lamps and salt stones for the construction of salt walls.

Even the ancient Indians mined salt in the salt mountains thousands of years ago. The reasons for this, in addition to the high degree of purity of the salt, are the very large deposits and the easy accessibility. In many places, the salt simply sticks out, similar to the salt domes in Transylvania in Romania. Even in the old days, it was comparatively easy to excavate a tunnel there, simply because of the ventilation, because you don't have to sink a shaft vertically, but only dig horizontally into the mountain. Below is a film with wonderful aerial shots of the salt mountains around Khewra and also excellent pictures of the inside of the salt mountain:

The old Indian Sanskrit name for rock salt is also a reference to the place, ‘saindhava lavana’ (सैन्धव लवण) translates as industrial salt or Indian salt. Because it was relatively easy to mine and could be extracted in large quantities in ancient times, the ancient Indians got all their rock salt from the salt mountains, which are now called "Kohistan-i-namak" in Pakistan (Urdu: کو ہستان نمک, English spelling: Kohistan E Namak). This Persian name is said to have been given by Babur (1483-1530), the first Mughal emperor of India (Persian was the court language of the Mughals). "Kohistan" means land of hills and "namak" means salt, i.e. land of salt hills.                                        
The Munich explorer and mountaineer Adolph von Schlagintweit (1829-1857) travelled through the salt mountains in 1857 and used this name in his Travelogue ➹. It can also be found in the Dierke Atlas, for example. It is difficult to say whether it is a translation from the Urdu word directly into German. It could well be that it is a translation from the word "salt range" used by the English, which in turn means "Kohistan-i-namak" translated into English. Although the British had ruled India for two hundred and fifty years, they did not conquer Punjab itself until 1849. As a result, British rock salt mining in India began very late, only in 1870 in Khewra - albeit at the highest industrial level of the time. The British built several mines in the salt mountains or expanded existing ones and provided them with the necessary infrastructure. Many of their buildings, bridges, railway tracks and even huts are still preserved today. In the mining town of Khewra (also Kheura, Kheora, near Schlagintweit Kiúra ➹, Urdu:کھیوڑہ ) there is even a slash used by the English, which is unfortunately no longer in use. From a technological point of view, the Pakistani form of salt extraction in the salt mountains today is inferior to that of the British at the time. This also explains why you can hardly marvel at any mining art there, in contrast to the time of British India. In the 1940s, there was even a fully automatic roundabout tipper for the mine cars - in addition to the Schräme. You can see this beautifully in this historical film:

Today, tractors with trailers and lorries are in use, apart, of course, from the visitor mine in Khwera, where an electric mine railway takes you into the tunnels.                                        

The word "Salzgebirge" also has a double meaning in German, however, because the miner refers to mineral resources either as ore mountains, coal mountains or even as salt mountains ➹. A "miner" works "underground" in a "mine", both of which come from the miner's language. For him, a mountain or a range does not necessarily have to protrude from the surface, because what counts for him are the mineral resources in the mountain. Whether a mountain rises above the ground is completely irrelevant to the miners. The numerous coal mines in the Ruhr region or the Lower Rhine salt mine in Borth speak for themselves, because "above ground" everything there is nice and flat.

Salt extraction in the salt mountains

In the salt mountains, salt is mined using the so-called chamber mining method. This involves creating long, high mining chambers and leaving pillars between them to support the overburden above. The salt is so stable that it is self-supporting and therefore no additional support is required, as in coal or ore mining, for example. There are generally huge halls to marvel at in salt mines, for example the famous Colombian salt cathedral in the salt mine of Zipaquirá, not far from the capital Bogota. You can also visit an eighty metre high cavern in the Khewra visitor mine in the salt mountains. The following short film gives a good impression of salt mining in the salt mountains:

The actual mining in Pakistan still involves a lot of manual labour, but no longer with mallets and iron (⚒), as was the case before the introduction of blasting technology:

Six holes are drilled into the salt by hand at specific intervals using a simple ratchet drill about one and a half metres long, operated by two drillers. This works very well because rock salt is a soft rock (Mohs hardness 2) and takes about a quarter of an hour per hole. The boreholes are then filled with black powder wrapped in newspaper. During the firing, the miners go round the corner to a safe place and the firing master ignites the explosive charges. They explode one after the other so that you can count. When the sixth explosion occurs and the gunpowder vapour has subsided, the miners return and begin to clear the roof, removing loose pieces of rock that are not firmly attached to the ceiling. In the salt mountains, this is also done by hand with crowbars. Truly not a sight for a German professional! When a loosener crashes off the ridge! In the Khewra show mine, you can even marvel at a cannon that is said to have been used especially for this purpose.

Afterwards, the labour-intensive process of picking up the lumps of salt and loading them into a trailer pulled by a tractor begins. The salt obtained in this way is driven out of the mine and processed further elsewhere.

In addition to solid salt, brine is also extracted in the salt mountains for the large soda factory in Khewra. The brine pools shimmer in a turquoise colour and can be easily seen from the air.

Salt building materials

For the production of table salt, the raw salt is crushed and ground into different grain sizes. White salt, red salt and clear salt are all used for this purpose. For other salt products, such as salt lamps and tea light holders, as well as salt building materials such as salt bricks, salt tiles and the like, red salt is used for the most part. For the production of salt lamps, tea light holders and lick stones, the corresponding holes are drilled into the salt stones using pillar drills. Salt bricks, salt blocks, salt bars and salt tiles are cut to size on stone saws designed for marble and granite and ground to size on grinding machines. Salt blocks, which are needed to build a natural salt wall, are hammered into different sizes by hand.

Because salt is crushed during mining and most of it is used as a raw material for the manufacture of plastics and chemical products, it is mainly the chemical composition that is important here. Since the 1990s, however, mountain salt has been used as decoration for the manufacture of salt lamps and, since the 2000s, as a building material for the production of salt bricks. This means that it is suddenly of great importance what the raw salt stone looks like. Whether it has crystal salt inclusions, because these may be predetermined breaking points, or clay inclusions, which give the stone a unique pattern, its dimensions and structure, as well as the different colour tones, now play a decisive role. Does the stone possibly contain Epsom salt, which could lead to unsightly efflorescence later on? The shades of red together with the different textures would give rise to a whole palette of different types of salt yet to be named. Perhaps in future there will be a corresponding classification for salt building materials, as there is for marble. We know the Carrara from Italy, the Thassos from Greece or the Estremoz from Portugal, each very clearly distinguishable from the other. Because rock salt as a building material is almost always illuminated, its colouring plays a very important role, or its colourlessness, as with crystal salt, or its cloudiness or milkiness. However, real blocks of a single crystal are very rare (see the crystal grotto in Merkers) and are therefore not used as a building material.

Salt extraction in the salt mountains is carried out using blasting technology, which is designed to make the salt as small as possible on site because most of it is crushed anyway. Of course, this mining method is not ideal for the salt building materials, as it causes a lot of damage. The salt is subjected to enormous pressures and often breaks in places that would have remained whole with a gentler extraction method. When marble extraction by blasting with black powder began in Cararra, Italy, during the Renaissance, waste rose to a third of production. You can still see these piles of unprocessable marble there today. Far too much good marble simply went to waste. Today, the marble is therefore cut out in large blocks using huge wire saws. These blocks are then sawn into thin slices using gang saws, which can then be easily cut up by stonemasons as required. Mountain salt, which is intended for the production of building materials, would have to be mined in a similar way. Admittedly on a smaller scale, because the extraction takes place underground. The mining process would have to take place underground;

So you could start by blasting out larger pieces, as a preliminary stage so to speak. However, this would then require the appropriate lifting technology. But that's what these pulley blocks on tripods are for, as used by stonemasons all over the world. However, this would not solve the actual problem that arises during sawing. After all, such a large chunk of quarry salt does not have a straight surface and is therefore wobbly when cut, which leads to major inaccuracies. But if it were a large cube, cut out with a small wire saw, then it would be much easier to cut. Not as big as in Italy, but much smaller, perhaps with an edge length of 50 centimetres. It would already weigh 275 kilos, with an edge length of one metre it would be eight times as much: 2.2 tonnes! The next step would be to cut these salt blocks into slices using an appropriately sized frame saw, after which the stone saws currently in use would be used again. This would then also make larger slabs possible. Until now, the size has been limited by the quarry stone to be sawn. For example, Pramodan & Dinesh offers a salt slab measuring 30 x 20 x 5 centimetres as standard. It is always possible to cut even larger slices out of a boulder, but this is the exception. With the extraction method described above, it could become the rule and larger slabs with an uninterrupted pattern could be offered.