From the granules used on your Sunday roast, to the variety that is spread across the globe during icy months, the uses of salt are far-reaching. Thankfully, the Earth is rich in salt and extraction methods have evolved over the years. From deep-shaft mining to solution mining, the multi-purpose equipment used today not only offers access to a global commodity, but it can also do so at a reduced cost, higher productivity rate and with control over underground carbon emissions.
Salt production from major countries grew by 7,000 (in 1,000 metric tons) between 2018 and 2019. The top five countries expected to have extracted the most salt in 2019 are:
1.China - 60,000
2.US - 42,000
3.India - 30,000
4.Germany - 14,000
5.Australia - 13,000
The global salt market is forecast to grow at an accelerated pace between 2019 and 2023.
Frequently asked questions about salt mines
How does a salt mine work?
There are two types of salt mining:
Deep-shaft mining: This uses the ‘room-and-pillar’ method, where shafts sink to the bottom of a mine and ‘rooms’ are created through cutting, drilling and blasting between these shafts in a checkerboard-like pattern; leaving supporting ‘pillars’. Once operational, machinery can then extract and crush the salt.
Solution mining: This involves constructing wells over salt domes and beds so that when tectonic pressure forces salt deposits out of the Earth, it can be collected by dissolving it with injections of water. The salt solution (also known as brine) is then transported to a plant to be treated before being evaporated; the remaining salt is then dried and refined.
What are salt mines used for?
Salt mines are used to extract rock salt which is then processed for a variety of uses such as:
- Tablets as animal feed
- Water softening
- Skin products
- Chemical production (solution-mined salt)
Some rock salt is edible, but only after the impurities have been removed.
How deep is a salt mine?
The depth of salt mines vary, however, the largest operating salt mine is the Sifto mine in Ontario; with depths reaching 1,800 feet below Lake Huron. This depth matches the height of the CN Tower.
What is the temperature in salt mines?
The temperature of a salt mine will vary depending on the depth of the mine; however, the average temperature is 70° F or 21° C.
Are salt mines dangerous?
Historically, salt mining was considered one of the most dangerous operations due to:
- Rapid dehydration caused by consistent contact with salt
- Excessive sodium intake
However, today, salt mining is considered to be the least dangerous form of mining; although, with the use of explosives in the ‘room-and-pillar method’, caution must always be maintained.
There is potential for a salt mine to collapse, with the last record of this happening being 1994.
Can you take a salt mine tour?
In addition to the actual mining of salt, many salt mines have opened their doors to commercial tours. Some of the tours you can take are located in:
- Wieliczka, Poland
- Krakow, Poland
- Salzburg, Austria
- Bavaria, Germany