New York State is home to the largest salt mines in the country. They’re in our backyard. Or, possibly even under it. 1000ft underground and 20,000+ acres. Are these massive underground mines safe?

Livingston County, NY, just south of Rochester, is the location of the Retsof mine, which began operation in 1884. Mining 1000 feet below ground, they extracted salt from what was to become the largest mine in the USA. The mine remained in continuous operation until 1994 when it began to take on water.

What started as a small leak in the Retsof Mine quickly became a big one. Water started to flow into the mine at a rate of 20,000 gallons an hour. They struggled to pump the water from the mines but were not able to keep up. Holes were drilled in the ground and cement injected in hopes to stop the leaks with no success.

The company fought to save Retsof mine, but ultimately extracted what they could, and abandoned it. Water eroded the giant pillars of salt that held the roof of the mine up and led to the collapse.

The ground above sank in as much as 12 feet. Natural gas began to vent from the land all around the county. And, wells went dry and have never come back. Geologists say that the mine will continue to collapse and the land will keep sinking over the next 100 years.

Three years after the Retsof Mine collapsed a company called American Rock Salt began a new mine just six miles north of the old mine. That new mine is now the largest in the nation and second-largest in the world. Operated by 400 workers, the mine produces over 18,000 tons of rock salt daily. The mine is estimated to last another 80 years. 

Tompkins County, NY is the location of the Cargill salt mine. The mine covers over 18,000 acres and is a half-mile underneath Cayuga Lake. At 2400′, it’s the deepest salt mine in the world.

Cargill purchased the mine in 1970 and it has been run continuously since. It employs over 200 workers and produces some 10,000 tons of salt a day. Cargill is the largest privately-owned company in the world. 

These two mega mines provide New York State and other states with the road salt used throughout the winter months. The salt is mined continuously 24/7 and 365 days a year to meet these demands. New York is one of the largest consumers of road salt in the nation. 

Since the collapse of the Retsof mine in 1994 scientists and activists have voiced understandable concern about the operations of the mines. The American Rock Salt mine is a massive estimated 20,000 plus acres. A collapse would mean the decimation of the local area.

While the American Rock Salt mine is a concern, the real worries are with the Cargill mine in Lansing. Because the mine exists directly below the second largest of the Finger Lakes its environmental threat is far greater. 

A collapse of the Cargill mine could mean the salinification of the lake, killing everything in it, and ruining the drinking water for thousands of people. Some geologists theorize that the water level of the lake could drop as much as 25′.

In 2017, Cargill sought permission from the state to drill a second shaft into the mine to expand the mine to the north. This fired up activists who rightfully pointed out that a second entrance to the mine increases the risk of flooding. Permission was granted and the tunnel was dug. The mine has operated since without incident. Activists pointed to the fact the mines are monitored by New York State who happens to be the largest customer, creating a conflict of interest. 

Whether or not the mines will have a long term environmental impact remains yet to be seen. The mines will continue to operate and grow. And, so will the demand for salt.