This giant truck travels on a glittering salt road 1,137 feet beneath Detroit, carrying newly-blasted salt several thousand feet to a primary crusher station.
It is a world of salt.
This gigantic salt mine, 1,200 feet beneath the surface, spreads out over more than 1,400 acres with 50 miles of roads. It lies underneath Dearborn's Rouge complex , much of Melvindale and the north end of Allen Park. The mine shaft opening is in Detroit.
The International Salt Mine Company operated the mines until 1983, when falling salt prices brought a halt to production.
Throughout history, salt has always been a precious commodity, often traded ounce for ounce for gold. Jesus called his disciples "the salt of the earth," a statement commemorated during Roman Catholic baptismal ceremonies by placing a few grains of salt on the child's tongue.
The Detroit Rock Salt Co. at 11400 West Fort St. in Detroit. This photo is from 1923.
The early Chinese used coins made of salt and in Europe many Mediterrean people used cakes of salt as currency. Roman soldiers were sometimes paid in salt. The word "salary" comes from "sal," the Latin word for salt.
The main sources of salt in ancient times were dry coastal areas near the Mediterranean. Early trade routes centered on Spain, Italy, Greece and Egypt. Many of the caravan trade routes were developed to transport salt, and Genoa, Pisa and Venice emerged as centers for the salt trade.
Throughout history, salt has been bartered and taxed. Wars have been fought over it, and lost because of a lack of it. According to some historians, Napoleon retreated from Russian partly because he lacked salt for his troops and horses.
Colonial America got most of its salt from England and with the onset of the Revolutionary War Benjamin Franklin made a secret deal with Bermuda to supply salt to the American forces.
In 1783, after the war had been won, salt works were set up along the Atlantic Coast. Major salt deposits found near Syracause provided one of the main reasons for the construction of the Erie Canal, which opened in 1825.
In Michigan, a huge sea covering the region evaporated more than 400 million years ago, forming salt deposits which were gradually buried by glacial activity. This salt bed spreads over 170,000 square miles under Michigan, Ontario, Ohio, Pennsylvania, New York and West Virginia.
A salt mine worker drills holes in the salt wall in preparation for the dynamite blasting.
Some estimates suggest that there is enough salt in the Metro Detroit underground to last 70 million years.
Michigan's Indian tribes used salt springs long before the white man came. Salt Creek, 32 miles west of Saginaw, supplied Indians and forest animals with salt crystallized from brine springs.
In 1841, Douglas Houghton supervised the sinking of the state's first salt well in central Michigan, the beginning of a series of borings that led to the establishment of the Dow Chemical Company and the discovery of the central Michigan oil and gas fields.
Salts are among the most important chemical compounds. They are used in making many industrial and agricultural chemicals. Sodium chloride is used in making chemicals needed in the manufacture of rayon, soap, and other products. Salt ammonium nitrate is used in fertilizers. Some metals, including sodium and potassium are extracted from salts.
Salt mining in Detroit began in 1896 with the sinking of an 1,100 foot shaft, but the investors went broke. Flooding and nastural gas killed six men died during the original construction, although there have been no deaths in the mines since.
The Detroit Salt Co. acquired the mineral rights and operated the shaft until 1907 when International Salt took over and drilled down to 1,200 feet. During the early days of Detroit Salt, the product was used mainly for homemade ice cream and cattle licks, but later the usage changed to industrial purposes and for ice and snow control for Michigan roads.
Mules, lowered by rope down the narrow shaft into the mine, were used in the early mining operations. Once down in the mines, they stayed there until they died.
Workers decended in a two-level elevator in which six men pressed face-to-face during the long ride down.
Getting equipment down into the massive cavern provided many problems. Pickup trucks, jeeps and large trucks had to be cut up or disassembled and lowered down the shaft piece by piece, to be reassembled in shop areas below. Large dump truck tires too big for the shaft had to be compressed and bound before they would fit down the opening
Huge rock boulders litter the cavern floor following the blasting procedure..
In a 1925 Detroit News article, miner Joel Payton told about his salt mine job. "The only dirty part of this job is going down to work," Mr. Payton explained.
"I have to wear this old outfit because the big buckets that take us down get smudgy from the action of the sulphur water on the iron of the buckets.
"The mine itself is dry and clean as pure rock salt in a solid vein 35 feet thick is bound to be. The high vaulted rooms that we have hollowed out have sparkling white floors, walls and ceilings."
Payton continued, "One reason we don't have any rats in our Detroit mine is because the rats would have nothing to eat except the leavings of our lunch pails. And by the way, not only are there no rats or cockroaches or other living creature in our mine, but also no remains of living things from past ages. The salt vein is, of course, a dried up sea that once covered this section for hundreds of miles. You'd naturally suppose that some fish or vegetation would have been pickled or fossilized in the brine as it hardened. But I've never seen a single fossil or sea shell or any remains of that kind"
The Detroit mine used the room-and-pillar method of removing salt from the ground. In room-and-pillar mining, shafts are sunk into the ground, and miners break up the rock salt with drills after detonation engineers had blasted a section. Each blast brought down 800 to 900 tons of rock salt. The miners removed chucks of salt, creating huge rooms separated by pillars of salt. The room-and-pillar method requires that about half of the salt be left behind as pillars for support.
The tunnels, dark and cavernous seem eerie lit only by truck lights or the single bulbs along the sides.
Huge rock boulders are loaded into railcars for the trip to the crusher.
In 1975 Detroit News reporter Maryhelen Stepp toured the operations with miner Harvey Poloni.
"Here we have no difference between night or day," Poloni said.
"It's all the same... and no claustrophobia, either."
"People seem to adjust without any difficulty. Smoking is allowed except in critical areas such as fuel depots and around the blasting materials. The air is fresh. Some say breathing in salt air is therapeutic," he said.
The salt, where blasting had just occurred, appears speckled-white, similar to rock salt available at stores.
Gargantuan trucks with seven foot tall wheels and 40-ton loads take the salt rocks to a primary crusher, where it is crunched down to football-size chunks. Thousands of feet of conveyor belts carry the salt through crushers and sorters until it is separated into sizes ranging from powdered crystals to lumps the size of sugar cubes.
The paychecks and the blasting stopped in 1983. Citing an inability to compete for state and local salt contracts because of cheaper Canadian salt and rising production costs, International Salt closed the Detroit mine, the oldest of five Midwest mines. Four mines, two in Ontario, and two in Ohio still tap the same salt vein that covers 80,000 square miles beneath several states.
In 1985 Crystal Mines Inc., a subsidiary of Wayne Disposal Co., purchased the mine. Owner Walter Tomyn reopened the facility for public tours, while seeking state permits to bury hazardous materials there. It offered, he claimed, safe storage for toxic refuse because the impermeable salt linings lie 600 feet below vulnerable ground water.
But in 1989 the state released a report contending that old wells dug near the Detroit salt mine might be pathways for water that could place the mines in danger of collapse.
Recently, the mines have reopened under the management of the Detroit Salt Co.
Workers travel around the mine in these specially built truck trailers.