A public forum was held on November 6, 2013 at SUNY Geneseo to present a summary of the experts' review and analysis of the Akzo Nobel (Akzo) Brine Pumping Test and Monitoring Program for the decommissioned Retsof Salt Mine. A PDF version of this fact sheet is available.
In March 1994, two sections of the ceiling at the southern end of the Retsof Mine collapsed. This allowed a continuous flow of groundwater into the mine, and by January 1996 it was completely flooded. This was the largest salt mine in North America and had been in operation for more than 100 years.
Since 1994, DEC, the NYS Attorney General's Office, and USGS staff have monitored the mine closure and the environmental effects associated with the collapse. Technical experts have conducted several scientific studies to determine the effects of the collapse and the flooding of the mine in order to assess potential future impacts related to the incident. Groundwater and salinity levels were monitored to understand the movement of water and brine within the collapse zone.
A number of investigations (including exploratory drilling, water-quality monitoring, geologic, hydrogeologic, and geophysical studies, numerical simulation of groundwater flow, and subsidence monitoring) have been undertaken to assess the environmental consequences of the mine collapse.
Pumping and Desalinization
Results of groundwater monitoring within the collapse zone were used to evaluate the potential for brine migration into the overlying aquifers. This evaluation led to a decision in April 2006 to allow Akzo to pump and treat brine squeezed from the mine on a trial basis to provide a better understanding of hydrogeologic conditions in the vicinity of the collapse, and to assess the sustainability of long-term pumping. The pumped water is treated in a thermal desalinization plant which results in the production of salt and distilled water. The distilled water is then discharged to Beards Creek.
As part of this program, Akzo was also required to follow a pumping test and monitoring plan developed in conjunction with DEC and the NYS Attorney General's Office. Under the program, Akzo regularly and periodically reported fluid level and water quality data obtained from pumping and monitoring wells, pumping rates, plant throughput, discharge monitoring data and subsidence data. This information was evaluated by DEC, the NYS Attorney General's Office and the United States Geological Survey. When necessary, changes to the protocol were made.
Experts at Alpha Geoscience and USGS have prepared reports (see links below) which summarize and evaluate the results of the pumping test and monitoring program and provide an assessment of potential future impacts. These reports have been reviewed by DEC and the Attorney General's Office.
USGS Report (PDF) - February 2013 (leaves DEC's website)
Alpha Geoscience Report (PDF) - February 2013 (leaves DEC's website)