LANSING, N.Y. — Cargill, Inc. submitted an application to the New York Department of Environmental Conservation (DEC) in June 2023 to modify its mining permit for its salt mine 2,000 feet under Cayuga Lake. The company wants to establish additional water storage areas to store groundwater leaking into the mine.
A representative from the DEC told The Ithaca Voice on Friday that the inflow of water outlined in the permit application is “not related to the lake” and is “not unanticipated.” The water entering the mine “is not a leak” and “is not associated with the lake,” the official said.
The department has been aware of the inflow of water from the shafts of the mine and the storage of it since the early 1990s, he said, as the company is required to report annually on the source and volume of the water inflow, as well as the storage location.
Groundwater in shafts 1, 2 and 3 have been recorded by engineers and researchers contracted by the company itself since at least 2017, according to Cargill’s 2018 Annual Review obtained by independent journalist Peter Mantius at Waterfront Online.
The 2023 application outlines plans to establish an additional 150-acre water storage area within an abandoned section of the mine referred to as S3, located at the southernmost portion of the mine closest to Ithaca, and the adjacent areas known as E3-E9. These areas are the deepest parts of the mine.
The storage of groundwater in abandoned parts of the mine is a “common industry practice,” according to Senior Global Communications Manager at Cargill Chuck Miller on Friday. At Lansing, the “primary sources of groundwater are in regions near shaft 1, which has been in place since 1916, and brine water from our operations.”
The new storage area in S3 is estimated to hold approximately 360 million gallons of water according to the application, and will fill at rates of about 1.3-1.8 million gallons per month, providing the mine “15-18 years of water storage at the current inflow rates.”
A copy of the company’s 2018 Annual Review shows the mine’s current storage area, which has a capacity of about 14 million gallons per year, was expected to reach capacity in approximately 6.1 years – or by 2023.
The representative from the DEC said the practice of pumping water to an underground settling pond to become fully saturated before being pumped to abandoned areas of the mine is a “common practice” in salt mines throughout the world.
“Because the water has accumulated over time, the area historically used for storage has filled and Cargill is seeking a new underground location to store water,” the department official said.
The current rate of water flowing into the mine is not included in Cargill’s application to modify the permit, despite language establishing that “inflow sources and rates are well understood,” and “groundwater inflow is managed by the facility.” The total amount of water that has entered the mine is also not provided.
The 2018 review included inflow rates from 2017-2018, which were recorded at approximately 36 gpm (gallons per minute). The figure is a total of all inflow rates measured at all points of inflow in shafts 1, 2 and 3.
The DEC representative did not reveal to The Voice the total amount of water that has entered the mine, nor the current inflow rate.
Since August of last year, local environmental activists and organizations have made concerted efforts to call on Gov. Kathy Hochul and the DEC to enhance their oversight efforts to protect Cayuga Lake from any potential environmental damages the mine could pose.
The effort intensified over the summer after reports that the company was interested in selling the mine. The company has yet to confirm or deny the report.
Cayuga Lake Environmental Action Now (CLEAN), a nonprofit advocacy group based in Lansing, unified other local organizations over their cause, and released an online petition in September 2023 that has been signed by over 3,000 people as of January 2024.
The application says a regular inspection of the water storage area in S3 will be conducted by a supervisor or engineer on a monthly basis to monitor ground conditions, check gas levels and record advances of the water shoreline.
Electronic convergence stations had already been installed in the S3 area by the time the application was submitted to the DEC this summer, to track changes in the rock that occur when salty water is introduced to a previously dry portion of a mine.
“All water stored in this area will be sufficiently saturated to minimize dissolution of the remaining salt pillars, floor and roof,” according to the application.
A representative from the DEC told The Voice on Friday that it’s reviewing the application and that the department “subjects every application to a rigorous review of all applicable federal and state standards to ensure the agency’s decisions are protective of public health and the environment.”
It’s accepted by experts that salty water can “destabilize overlying rock layers and lead to their eventual sagging and collapse,” according to a 2013 Geological Survey Report by the U.S. Department of Interior on the 1994 collapse of the Retsof Salt Mine, which damaged the environment and soiled drinking water for years after.
Groundwater has the potential to flood an entire mine and has been described in academic publications as a “constant source of concern” for mine operators, particularly in salt mining.
“Salt mines are generally dry, but are susceptible to leaks and can become flooded if groundwater from overlying aquifers or surface water finds a way downward into the mined cavity through hundreds of feet of rock,” according to the Geological Survey Report.
Salt is highly soluble in water. This solubility, according to the report, makes it so that when water begins to flow into a salt mine, the channels it flows through increase in diameter as the surrounding salt dissolves.
“Some mines leak at a slow rate for decades before a section of rock gives way, allowing what initially was a trickle of water to suddenly become a cascade and finally a torrent,” the report says.
The representative from the DEC said the department will continue to provide comprehensive oversight of the facility, including monitoring rates of inflow, to ensure it remains in compliance with its permits and all laws and regulations in place to protect public health and the environment.”