2016 NGWA Groundwater Summit

Geologic Feasibility of Class I Injection Wells in the Deep Portions of the Illinois Basin

Tuesday, April 26, 2016: 1:30 p.m.
Confluence Ballroom A (The Westin Denver Downtown)
Stephanie Hill , SCS Aquaterra, Fairview Heights, IL, United States
Monte Markley, P.G. , SCS Aquaterra, Wichita, KS

The Illinois Basin has experienced a resurgence of underground long wall coal mining operations with the migration of Appalachia-based mining companies over the last decade. This type of mining is conducted under hydraulic roof supports that advance as the coal seam is cut. As the supports advance, the roof collapses behind the cutting head, causing fractures to propagate through water-bearing sandstone formations and resulting in large volumes of fluid infiltrating into the underground workings. Up to 2 million gallons per day have been produced in the southern Illinois mines. The native groundwater contains naturally-occurring elevated chlorides that exceed surface water effluent limitations and are not permitted to discharge to Illinois surface waters. However, the fluid is permitted to be disposed of in Class I non-hazardous wells.

Because there is sparsely documented information available from deep boreholes in the southern part of the state, information from central and northern Illinois was extrapolated for purposes of evaluating the geologic suitability of selected injection intervals for fluid disposal in the deepest portions of the basin. Exploratory boreholes were drilled for two underground coal operations into or near the Precambrian basement with total depths ranging 12,000-13,000 feet. The wells were completed as partially perforated cased/open hole through the injection interval. Cores taken during initial drilling of the boreholes supported published data that one formation displayed vugs that appeared to be interconnected, but laboratory tests revealed an over-consolidated, low porosity and permeability formation lacking interconnectivity of voids. Furthermore, the most suitable formation is thin or absent in the deeper Basin. This presentation will explore the successes and lessons learned from completion and testing of these deep injection wells and examine future drilling and completion practices within the deeper portion of the Illinois Basin.

Stephanie Hill, SCS Aquaterra, Fairview Heights, IL, United States
Stephanie Hill obtained a Bachelor of Science degree from the University of Texas at Austin in geological sciences with a focus on hydrogeology. Ms. Hill is currently a project director with SCS Aquaterra and oversees the St. Louis area operations. Previously, she directed the Title V coal permitting and reclamation program at the Railroad Commission of Texas. Stephanie is active in several professional organizations including the Society of American Military Engineers, Illinois Groundwater Association, National Ground Water Association and Groundwater Protection Council.

Monte Markley, P.G., SCS Aquaterra, Wichita, KS
Monte is a native of Wichita, Kansas and attended Lamar University in Beaumont, Texas where he earned a B.S. in Geology. After beginning his career in engineering geology and environmental work on the Gulf Coast, he moved back to the Wichita area in the early 1990’s. His focus has been on managing large mutli-disciplinary teams to execute water supply, groundwater remediation/beneficial reuse, solid waste and geological consulting projects. He is a licensed professional geologist in Kansas and Missouri and is active in several professional groups: Solid Waste Association of North America, Ground Water Protection Council, Kansas Geological Survey.