Inver Grove Heights (Pine Bend Area)
Special Well and Boring Construction Area
Well Management Program
Koch Refinery, North Star Chemical, St. Paul Ammonia, Pine Bend Landfill, and Crosby-American Landfill are located in Pine Bend, approximately 10 miles south of St. Paul and 1/2 to 1 mile west of the Mississippi River in Dakota County. Koch Refining was constructed in the 1950s to refine high-sulfur crude oil imported by pipeline from the oil fields of the Province of Alberta, Canada. Numerous petro-chemical industries associated with the refinery were built in the area. Pine Bend Sanitary Landfill and Crosby-American Landfill began operation in the early 1970s, accepting mixed municipal solid waste and demolition wastes.
In December of 1972, in response to complaints to the Minnesota Pollution Control Agency (MPCA) from well owners about tastes and ammonia odors, the Minnesota Department of Health (MDH) sampled a number of wells to the east of the refinery. Reports from the refinery indicated that process water holding ponds were leaking millions of gallons of waste water to the ground. Further well sampling was done in 1972. Contamination with metals, phenols, ammonia, and lowered Ph was reported.
On April 19, 1973, the Minnesota Department of Health contacted the Village of Inver Grove Heights requesting their assistance to control well construction in Sections 33, 34, and 35, T27N, R22W. The Department requested that before any well permit is issued for construction of a new well or reconstruction of an existing well, the Health Department be contacted.
A series of hydrologic investigations have been conducted. The Koch, Northstar, and St. Paul Ammonia sites have been combined into a single Permanent List of Priorities (PLP) site (superfund) by the Minnesota Pollution Control Agency. The Pine Bend and Crosby-American Sites have been combined into a single PLP site. Recent groundwater monitoring has detected the presence of Volatile Organic Chemicals (VOCs) which are apparently associated with both PLP sites. Solvents have been detected near the landfills, and petroleum products near the industrial sites.
Thirty one different VOCs have been detected in monitoring wells at the landfill. Two private wells have detectable levels of 1,1, trichloroethane, cis-1,2 dichloroethylene, 1,1,dichloroethane, 1,2 dichloroethane, chloroform, toluene, chlorinated fluoromethanes (freons) and ethyl ether. The owners of the two water-supply wells downgradient of the landfills have been issued advisories by the Minnesota Department of Health to discontinue use of the water for drinking and food preparation. Four additional wells have shown detectable levels of VOCs but have not been issued an advisory to discontinue use. All affected wells have been provided bottled water. Efforts are being made to extend municipal water to the area. The refinery has purchased properties where wells have been affected and is providing bottled water to three residents.
The geology of the area consists of varying thicknesses of glacial sediments and alluvium overlying bedrock, ranging from the Prairie du Chien formation to the Franconia in the center of a deep buried bedrock valley. The bedrock valley is 450 feet deep in some areas. Groundwater flow is generally to the east and northeast toward the Mississippi River.
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Contact the MDH Well Management Section
651-201-4600 or 800-383-9808
Minnesota Department of Health