Presentation on theme: "LCMR Study of the Hydraulic Impacts of Limestone Quarries and Gravel Pits Jeffrey A. Green P.G. Jeremy A. Pavlish Minnesota Department of Natural Resources."— Presentation transcript:
LCMR Study of the Hydraulic Impacts of Limestone Quarries and Gravel Pits Jeffrey A. Green P.G. Jeremy A. Pavlish Minnesota Department of Natural Resources Division of Waters
Quarries and pits can affect ground-water and surface-water systems in various ways. lowering of local ground-water and surface-water levels from mining operations and mine dewatering changes in turbidity levels in ground water due to blasting and quarry operations interruption of ground-water conduit flow paths by rock removal temperature change (thermal impacts) in springs and surface-water streams
Previously Documented Impacts Lundin and Fretham Quarries, Steele County Quarries mined Galena limestone and dewatered to allow dry mining. Lundin was in operation from ~1969 to 1987 Fretham was in operation with continuous dewatering from 1976 to present.
Documented Impacts (cont.) Between 1986 and 1992, three domestic well interferences were filed. All three wells were located 1000 to 1300 from the Fretham Quarry. All three wells were constructed into the Galena and were shallower than the depth of the quarries.
The DNR Division of Waters investigated and determined that the quarry dewatering was the cause of the out-of-water complaints for the three domestic wells The company involved agreed to have the homes connected to the municipal water supply
Documented Impacts (cont.) LeRoy Quarry, Mower County. Sub-water table limestone quarry. Quarry dewaters at a rate of about 200 to 800 gpm in order to mine. Several dye traces have been performed in and around the the quarry to map both the natural and disrupted ground water flow.
LCMR Study of the Hydraulic Impacts of Limestone Quarries and Gravel Pits
Why we did this study. Quarries and gravel pits are necessary for society. Potential exists for impacts to ground water. Many LGUs have questions about the impacts. Little information on those impacts.
The Hydraulic Impacts of Limestone Quarries and Gravel Pits Study was funded by the 2001 Legislature as recommended by the Legislative Commission on Minnesota Resources. Funding is from the Environment and Natural Resources Trust Fund.
Objectives Study the relationship between quarries, gravel pits and ground water systems. Better understanding of conditions that lead to ground water impacts.
Video logging Results- Kraemer & Golberg Quarry Wells During the spring of 2005, DNR Waters staff used a downhole camera to inspect the 5 observation wells at these sites Staff inspected both the cased and open hole sections No deformation or damage to the cased portions of the wells was visible No obvious impacts to the open hole sections were visible Preferential (conduit flow) was observed in several of the wells