The Tarapaca salt mine
I always wanted to visit an open pit salt mine, for the simple fact that they are hard to find. After all, it has to be a very dry climate such that the salt is not washed away by the rain, that is so common in more temperate climates. So when K+S made it possible to visit its Tarapaca salt mine, I was more than excited.
The mine is located in the Atacama desert, south of Iquique, and a mere 30km from the coast. Therefore it is very dry, and no salt can dissolve and get lost. Its location is very advantageous since the short distance to the coast reduces its transportation costs, which is paramount for industrial minerals. In addition, the deposit is very shallow, which further reduces production costs. If all these great features are not enough, the reserves will also last for another 5000 years. However, the mine produces not just salt, but a very complex set of different qualities that are useful for different applications. Not only does the mine produce table salt for your scrambled eggs, but also different varieties of chemical (ie. the blue dots in your dishwasher soap is dyed salt) and industrial salts, as well as also de-icing salt for winter roads. Therefore, I think that all in all it is quite an exceptional mine in terms of products, economics and logistics.
So how does the salt transform from a commodity in the mine to an end product like the table salt you use at your breakfast table. Well, I assure you, it is not exactly rocket science, but merely the application of plain old mining technologies.
It starts like in most other mines with the drilling of blast holes. These are filled with blasting agents, and when everybody is outside the blasting area, the salt is blasted into pieces. This happens at Tarapaca once a day.
Next comes the loader and places the material onto a haul truck, which in turn transports it to the primary crusher. From there it is moved to the secondary crusher while sieves subsequently separate the oversize material from the pre-adjusted product size. The oversize material goes to the tertiary crusher and is fed back into the circuit until the product size specification has been met. At Tarapaca, four of these crushing circuits exists, where the different types of products can be made. However most of the products can be made in any of the circuits employing batch processing. What is important is that right from the start the material is mined selectively and kept separate through the processing to the shipping stages.
When all the crushing and classifying is done, the different products are then trucked to the port where they are put on different heaps according to their product specifications, determined mostly by their chemical composition. The bulk of the different salt products is then shipped out from the two loading facilities to markets around the world. As an example, the de-icing salt is mostly shipped to the East coast of the United States (and peak production time is therefore during the nordic winter, ie. southern summer). When one considers that salt is usually a low value product it is therefore astounding that this is economical. However the overall short hauling distance from mine to port and the generally low transportation costs by ship allow for that.
However, not all salt is put into bulk carrier ships and transported to distant places. A smaller share of the salt is actually transformed into table salt right at the port facility. It is also there where iodine or fluoride can be added – all this according to the regulation or customer requirements. When it is packed and labelled it is then trucked straight to the retail facilities and supermarkets in Chile, Bolivia and Peru. In fact if you buy salt in a shop in Chile, it is almost impossible to get any that is not from this mine. It is just marketed by different entities under different brands.
For my breakfast of course, I stick with the Chilean house brand – Lobos. Knowing where my salt is coming from, it will taste so much better. Guten Appetit!