Along the Water

Cleveland’s salt mine: marking 50 years in ideal location under Lake Erie

Cleveland’s salt mine is both a feat of engineering and a hidden gem. Located 1,800 feet below Lake Erie, the mine is comprised of giant excavated tunnels 20-feet high, 45-feet wide extend four miles out from the shoreline. That’s where Cargill Deicing Technology extracts rock salt from a basin more than 300 million years old so that modern-day drivers can safely maneuver winter roads. Thanks to ancient geology, man-made transportation systems, and consumer demand, Cargill’s location in the heart of the city is ideal for mining salt.

“Just begin with the fact that it sits on one of the largest salt basins in the entire world, and you can see why Cleveland is a great place to mine,” said Richard Maxfield, president of Cargill Deicing Technology, which has owned and operated the mine since 1997, and doubled production since that time.  “But that is one factor of many that attracted us to this mine.”

This year marks the 50th anniversary of the opening of the mine. But the salt basin itself is ancient. Formed more than 300 million years ago, it extends through parts of four states, explained Chris Gill, the Cleveland mine’s superintendent. “As the Appalachian Mountains formed, they cut off a section of the Atlantic, which evaporated and left behind massive salt deposits,” said Gill. “Over the millennia, normal buildup of soil and rock covered the salt, and those layers, in turn, were eventually covered by the glaciers which melted to form the Great Lakes.”

The mine’s location also has more contemporary advantages.  It’s in the heart of the industrial snow belt, and unlike most other mines around the country, has ready access to three major forms of transport — boat, truck, and rail. That means Cargill and its employees can serve more markets.  “We ship over a million tons by each mode annually,” Gill said. “This is possibly the most cost effective mine in the U.S.” All told the mine produces about four million tons of rock salt annually.

The Cleveland salt serves markets from Duluth, Minnesota to Montreal, Canada, with government users making up about 80 percent of the customer base. The rest are private contractors.

Travelling from the above-ground facilities on Whiskey Island to the active mining areas is an adventure for the uninitiated.  Two elevator shafts provide access to the mine, one for workers and equipment, the other for salt to be hauled out. A five-minute ride down a shaft twice the height of Cleveland’s Key Tower takes workers down to a honeycomb of giant tunnels mine where they board “people mover” trucks for a 20-minute, four-mile ride out to the current work area.  The mine is organized in a “room and pillar system” that leaves central pillars of salt to hold up the structure. Each room is 40 by 40 feet, and five mining units run simultaneously round the clock to open 40 acres of new mine annually.

Workers drill holes in un-mined areas then place explosives and blast salt free while also opening up new areas for excavation. Dump trucks then transport the salt back to the cargo shaft to be carried to the surface.  “Our engineers and geologists perform ongoing seismic tests as we move out to ensure our workers’ safety,” Maxfield said. 

Once brought to the surface, the salt is loaded on boats capable of carrying 15,000 tons each (about 7,500 full snowplow trucks worth). The vessels dock directly at the mine site during the May-to-December shipping season.  Those ships then transport the salt to some of Cargill’s 80 terminals across North America. Salt is also loaded directly on rail cars to service additional markets.

Cargill is the largest outbound shipper along the Cuyahoga River ship channel.  “We ship out 80 to 90 boats a year, with 10 of those heading up river to provide stockpiles loaded into trucks for local market, so we appreciate a strong partner in the Port,” said Gill.  Those local stockpiles provide up to 200,000 tons (roughly 8,000 trucks full) of salt a day during the height of the winter deicing season, and Cargill provided half a million tons of salt for Ohio users in 2012.

Cargill Deicing Technology is a subsidiary of Minnesota-based Cargill International, the world’s largest privately held company. Cargill’s salt operations are headquartered in Cleveland, with 80 employees at its North Olmsted offices and 200 at the Cleveland mine. Another 400 are employed at mines in Louisiana and New York. “Cleveland is also a great place for a mine because of its accessibility to a high quality labor force,” said Maxfield. “In more remote mines, it’s difficult to attract this type of workforce.”

With 50 years under its belt, the Cleveland mine has many more to go.  Maxfield estimates the mine’s useful life could extend another 75 to 100 years. “We look forward to our Cleveland mine being a top producer for generations to come,” he said.

FAST FACTS

  • The Cleveland mine is part of a large salt formation known as the Salina Group that runs below parts of the Great Lakes region.
  • The depth at which salt is found in the Salina Group varies from 800 feet to more than 6,000 feet.
  • Lake Erie’s waters have an average depth of 50 feet above the Cleveland mine.
  • Layers of shale, limestone, sandstone, and dolemite separate the mine from the lake.
  • The layer of limestone at roughly 1,200 feet makes the mine a stable setting for excavation and provides an impervious cap that keeps from moisture seeping into the mine.
  • A total of three salt layers exist below Lake Erie, the first unsuitable for mining, the second currently being excavated, and the third and lowest layer reserved for future use under Cargill’s 80-year lease with The State of Ohio.