Salt Of The Earth: The Ultimate Guide To Road Salt

Beautiful isn’t it, you could be forgiven for confusing the picture to the right with a Diamond.Minneapolis Parking Lot Salting

The image is in actuality of a far more useful crystal, salt. That’s right, salt in the US is a must have for any cold weather state. Every year 19 million tons of rock salt are flung across the roads, sidewalks, and driveways across the United States. Be it from the back of dump trucks, pickup spreaders, hand spreaders or even by shovel. Once this wonderful mineral begins to work its magic and lower the freezing point of the ice, there is no turning back for that dastardly villain. My point is salt is a big deal, it allows schools, business’, and roads to be used in almost any weather. The application of salt to roads undoubtedly saves lives, a study conducted in Wisconsin found that road salt reduced crashes by 88%, injuries by 85% and accident costs by 85%.

Where Does Road Salt Come From?

So what is the history behind this dinner table accouterments that is so integral to the maintenance of our country’s transportation infrastructure? As far back as the 7th century BC salt has played an essential part in trade between civilizations. Even today the importance that was given to salt in the ancient world can be seen in our language, the words salary and salad are derived from salt. Salt has even had a part in wars, if we move forward a “little” in time, it was a major factor in the Revolutionary war, the British used Loyalists to intercept Revolutionaries’ salt shipments which impaired their ability to preserve food. Even during the war of 1812, soldiers in the field were paid in salt brine as the government was too poor to pay them. In 1895 concentrated rock salt was discovered under detroit, by 1914 the mine was producing 8000 tons of rock salt per year. The salt mine under Detroit is still active and has a massive complex of nearly 100 miles of tunnels under the city. Finally in 1940, Detroit became the first city in the world to apply rock salt to its roads to counteract icy conditions. It wasn’t long before the rest of the world caught on and followed suit, meaning for the first time in history roads and highways could safely be used all year round.

Salt Mine

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Salt demand and production has come a long way since it was transported out of a pit by mules in the 20th century. In the winter of 1941-42 only 5000 tons of salt were used in the whole country, compared to the 19 million tons used in 2014-15. Salt in the modern era is big business, for the year 2014 salt production was a $2.2 billion industry according to a USG survey. As the network of roads expands each year in the US so does the demand for salt to keep those same roads clear of ice for its citizens. So as demand has grown with each new winter season so too has the mining effort and the technology that goes with it. Gone are the mules and ropes and pulleys that once raised the salt to the surface, gone are the pickaxes and miners that wielded them. In came the dump trucks, conveyors and dynamite. To transport the salt around the country and world, new larger more efficient means of transportation had to be developed. Often the demand for salt is so large that the supply simply is not there in the US and the salt has to be imported from other countries. The salt is shipped in ocean faring vessels and arrives to the US and is then distributed to the locations of demand either by rail or by a smaller river barge. Often traveling hundreds more miles as is the case with Minnesota, who receive their salt shipments via barge that has traveled all the way up the Mississippi river.

minneapolis salt barge

The Price of Salt and Alternatives

As salt is a commodity and is priced on demand, often the price of salt can fluctuate greatly. However once the winter season is back in mind for state and city works departments, the demand for salt and its price can skyrocket. You might ask why not buy salt in the summer months when the price is low. The problem with this is it is often impractical to store salt for long periods of time, as if salt gets damp or wet it can undergo a chemical reaction causing it to become rock solid and thus making it almost unusable. So buyers are captive to the problem of supply and demand.

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Salt spreaderThis has led to many states trialing new ways of dealing with the icy conditions that step away from the use of traditional rock salt. One of the biggest success’ in alternate deicing materials has been cheese brine. The state of Wisconsin had the problem of increasing salt costs and the cheese production industry had the problem of disposing of its cheese brine that also had its own increasing cost. The solution was of course for the cheese industry to supply the state of Wisconsin with their waste product. There are other added benefits to some of these alternative deicers, for example salt brine freezes at -6F but cheese brine freezes at -21F so cheese brine is a far superior deicer. While cheese brine can not ever fully replace rock salt due to the sheer amount needed it can offset the amount required and thus bring down the overall operating cost to the state.

Currently there are no alternatives to salt that can match its abundance and so dethrone it as the main product used to deice the roads of the world. So it seems that salt the mineral that has been so important to us for over 9 millenia will continue to be just as important to us as we move forward. Allowing us to travel and get to work, see loved ones and make emergency trips during those miserable winter months. So as I said salt is Beautiful.