DEC to Cargill: Give Us Detailed Reports on Potential Dangers of New Storage Site for Water Leaking Into Cayuga Salt Mine

LANSING, Jan. 18, 2024 — State regulators late yesterday renewed their bid to obtain consultant reports from Cargill Inc. that analyze the effects of storing brine in the deepest section of its rock salt mine under Cayuga Lake.

So far, the company has only shown the state Department of Environmental Conservation quotable passages from several reports that delve into the likely weakening of the roof and pillars in the section labeled “S3” if and when it is filled. 

For example, one reports says, “…portions of the roof are especially susceptible to deterioration and failure as the panel is flooded.” 

But the same April 2022 analysis by Agapito Associates Inc. goes on to say, “… flooding the panels off the S3 Submain for water storage is not likely to give rise to global instability that could potentially cause rapid ejection water from the panels and potential flooding of other mine areas.”

According to the excerpts WaterFront obtained from DEC under the Freedom of Information Law, Cargill rejected a 2021 report from Respec because it was based on what the company called an “unrealistic assumption” that a 15-foot-thick layer of claystone roof “lost 95 percent of its rock mass strength instantly at the onset of storage.”

Cargill countered that any loss of rock strength would occur gradually as the section slowly fills.

The company notified the DEC last January that it planned to start using S3 to store waters that constantly seep or flow into the mine. 

Groundwater has been entering the mine at the relatively steady rate of about 30-35 gallons per minute in recent years, according Cargill annual reports. But the section of the mine customarily used to store those inflows on Level 4 is full.

The S3 area on Level 6 covers 150 acres at the extreme south end of the mine, at least six miles away from current salt mining. It has an estimated capacity of 360 million gallons — more than enough to fill 500 Olympic-size swimming pools.

To buttress its plan to begin using the S3 section for brine storage, Cargill provided the DEC a report from its consultant, John T. Boyd Co., which found minimal risks based on its review of the undisclosed consultant reports. (Boyd wasn’t shown the 2021 Respec analysis).

In response, the agency told the company it would need to apply for a modification to its state mining permit. Cargill filed the application in June, and, according to the DEC, began filling S3 later in the summer as the agency considered its application.

On Wednesday, the DEC sent Cargill a formal Notice of Incomplete Application for the permit modification. The NOIA requests what an agency analyst had asked for three months ago: all the undisclosed consultant reports.

The snippets of those reports WaterFront obtained indicate that the roof and pillars of S3 are more vulnerable to deterioration as humidity rises, especially if the stored water has not been fully saturated with salt.

Fully saturated brine is 26.6 percent salt by weight, a Cargill engineer wrote in Dec. 16, 2022 memo to Boyd. Inflows are significantly less concentrated. 

Because the brine in the Cayuga mine averages only 20-22 percent salt, the engineer said, Cargill planned to build a system to raise it to 24-25 percent salt before pumping it to S3 so as to minimize damage to its salt pillars.

Cargill declined this week to provide the current rate of inflows to the Cayuga mine, which has headquarters in Lansing about six miles north of Ithaca on the lake’s eastern shore.

Any significant increase in that inflow rate could have grave consequences for the stability of the mine.

Groundwater is a constant source of concern for mine operations because of its potential to flood the entire mine, Richard Yager wrote in a 2013 U.S. Geological Survey report on the collapse of the Restof mine in Livingston County in 1994. 

“Some mines leak at a slow rate for decades before a section of the mine gives way, allowing what initially was a trickle of water to suddenly become a cascade and finally a torrent,” Yager wrote.

WaterFront found no evidence the Cayuga mine is on the brink of any such catastrophe. And Cargill’s most recent annual report, released last February, said, “The mine is behaving as expected and global stability continues to be maintained.”

But environmental advocates have long argued that the DEC — to say nothing of the public — lacks the information needed to understand when risks of a total mine failure are rising. Such an event, advocates warn, could threaten the salinity level of the lake, which serves as a drinking water source for about 100,000 people.

In July,  worries about mine safety surged after The Deal, a Manhattan-based financial website, reported that Cargill was trying to sell the Cayuga mine and exit the U.S. salt business. Cargill has not confirmed or denied those reports, which cited sources that said it had hired Deutsche Bank AG to help find a buyer.

The unconfirmed report alarmed many in the Lansing and Ithaca communities and prompted state legislation to block any hasty sale.

The state must not allow a company with little mining background to assume Cargill’s state permits to mine, said Brian Eden, co-founder of Cayuga Lake Environmental Action Now (CLEAN). “The threat of a private equity firm (buying the mine and then) reducing costs to take quick profits is unacceptable,” Eden said.

In November, state Sen. Lea Webb (D-Binghamton) introduced a bill that would require Cargill or a future mine buyer to provide financial security to cover damages due to a roof collapse or mine flood that salinates the lake. Assemblymember Anna Kelles (D-Ithaca) sponsored a companion bill in the state Assembly. Both measures would also require Cargill to prepare its first environmental impact statement (EIS) and a comprehensive plan to close the mine after all mining ceases.

“Cargill can’t skip town and leave Finger Lakes communities holding the bag,” Kelles said. “…Billions of dollars need to be set aside by whatever company owns it. Right now it’s Cargill.”

Cargill currently provides $3.5 million in financial assurance. While the pending bills don’t include a specific dollar amount, Cayuga Lake Watershed Network has urged Gov. Kathy Hochul to require Cargill or a future buyer to post a bond of at least $1 billion.

Meanwhile, a petition drafted by CLEAN that calls for a bond of $10 billion and an EIS now has more than 3,200 signatures. “An independent review will shed critical light on the on-going risks of mine collapse, lake salinization, and other damage to the surrounding land,” the petition says. 

That grass roots movement is reminiscent of public groundswells that prodded former Gov. Andrew Cuomo to ban fracking statewide in 2014 and to block construction of a proposed Finger Lakes garbage incinerator in 2018.

Hochul is now the sixth New York governor to allow Cargill to operate the Cayuga mine without preparing an environmental impact statement. The EIS process, which emphasizes public involvement, is required under the 1975 State Environmental Quality Review Act for any activity that “is determined to have potential impacts on the environment.” 

But Cargill took control of the Cayuga mine in 1970, and the DEC has for decades prioritized the company’s insistence on secrecy over the public’s calls for transparency.

Acting in sync with Cargill’s legal team, attorneys for the DEC have successfully argued in court against the state requiring an EIS for the Cayuga mine.

Several days after WaterFront’s Nov. 29 request to the DEC for a copy of Cargill’s June 30, 2023 application for a permit modification, mine manager Shawn Wilczynsk emailed a DEC official: “How did anyone … even know we had submitted an application?”

The DEC declined to provide a copy of the application for several weeks. It finally surrendered the document after WaterFront reported that the agency was treating it as a state secret.

Details in the application to modify the permit and correspondence between the agency and the company about the application — all obtained by WaterFront under FOIL — repeatedly address ways the inflows could impair the roof of the new storage area.

Roof collapses endanger miners and can lead to uncontrolled flooding of an entire mine. Roof falls preceded the total failures of Morton’s Himrod rock salt mine in Yates County, NY, in 1974, Akzo Nobel’s Retsof mine in Livingston County, NY, in 1994, and Cargill’s Avery Island mine in Louisiana in 2020. 

Miners died in both the Himrod and Avery Island roof falls. 

The Retsof mine failure caused massive sinkholes and extensive damage to local roads, bridges and water wells. 

Several years before Morton closed its Himrod mine, an accident at the site sent many tons of salt into Seneca Lake. “That caused the lake to go from 70 parts per million of salt to 180 to 200 parts per million,” Professor John Halfman of Hobart and William Smith Colleges told the Finger Lakes Times in 2015.

Roof falls at Himrod, Retsof and Avery Island were preceded by limited or moderate leaks that later grew into heavier inflows. 

While Cargill declined to reveal the current rate of water inflows to the mine, company spokesperson Chuck Miller issued the following statement Wednesday:

“Storage of groundwater in abandoned parts of a mine is a common industry practice, including at the Lansing mine for many decades. The primary sources at Lansing are groundwater in regions near the #1 shaft, which has been in place since 1916, and brine water from our operations.”

On Jan. 16, WaterFront asked Cargill specific questions concerning its plan to store inflows and brine in the S3 section of the mine. The company declined to address them directly. The questions and full response are here.

The DEC said in a statement late Wednesday that Cargill did not violate its current state mining permit — which expires in April — when it began storing water in the S3 area last summer.

So any delay in obtaining the permit modification due to the Notice of Incomplete Application will have little or no effect on Cargill’s mining practices. However, if and when DEC deems the application complete, a 30-day public notice period will begin and Cargill will have to publish the completed application.

The company says it goes to great lengths to operate safely and to monitor the stability of the mine. In its 2022 annual report, the company describes its use of more than 300 “convergence stations” to detect any signs of troubling rock movements. 

“Evaluations of the convergence data indicate that overall no unusual trends have been identified and the mine is behaving as expected,” the report said.

In its permit modification application, the company said it plans to continue monitoring convergence within S3, at least until those stations are flooded and no longer useful.

In its October assessment of Cargill’s plans to store inflows in S3, a DEC analyst asked the company to “please estimate the approximate dates that convergence monitoring stations will be inundated, preventing safe access and necessitating abandonment of the stations….

“Please address the progressive loss of monitoring stations with respect to the need for continued monitoring of global stability….”