MOVEMENT AND CONTROL OF BRINE IN AQUIFERS ABOVE THE RETSOF SALT MINE IN THE GENESEE RIVER VALLEY, NEW YORK

The Retsof Salt Mine in Livingston County, New York had completely filled with saturated brine by 1996 following a collapse on March 12, 1994 and subsequent flooding by water entering from overlying bedrock and unconsolidated aquifers. The ground water from these aquifers entered the mine and dissolved salt pillars and subsequently created two large collapse chimneys with associated sinkholes at the surface. The flooded mine has an areal dimension of approximately 11.2 square miles at an average depth of 1100 feet. Ground water which originated from aquifers in the bedrock and near the base of a 500 ft thick sequence of glacial deposits, entered through the collapse zone near the southern downdip limits of the mine.

The 16.8 billion gallons of water in the mine is fully saturated with salt and is being squeezed out of the mine by the roof to floor closure caused by the weight of the overlying rock and glacial deposits. This brine rose through the rubble chimney and began to push saline water into the aquifer system near the top of the rock and the base of the glacial valley fill deposits ten years after the initial collapse. The State of New York has required the former operator of the mine to protect the aquifer system from salt water intrusion. An extensive plan of monitoring and pumping was developed and implemented with the goal of stabilizing the upward movement of brine and the associated saline water.

The monitoring data suggest that the mitigation approach has been successful at stabilizing the brine movement while preventing fresher water from being drawn into the salt horizons which would lead to further salt dissolution and potential subsidence. The removal rates close to the brine squeeze rate also allows for an even lateral removal along fracture sets preventing localized areas of upwelling or fresh water drawdown.