Class I, Non-Hazardous Injection Well, Southern Illinois

Underground Coal Mining Operation

Geologic expertise and experience are essential for securing deep injection well permit approval.

Our client had installed two 13,000-foot exploratory boreholes at their mining facility expecting to be able to inject high chloride (native groundwater inflow from underground mining operations). They had submitted permit applications to convert the boreholes to deep injection wells but were unable to secure a permit to do so. The State of Illinois had not approved deep injection wells for many years and needed to be satisfied that the proposed injection wells would not adversely affect the environment.

Part of the problem was that detailed information was not available for the subsurface formations at the borehole depths. The project needed the involvement of a company with geologic expertise and deep injection well experience for the regulators to feel comfortable, the permit to be approved and the project to proceed.


SCS Engineers was initially engaged to review the previously-submitted underground injection control (UIC) Class I permit application. Based on our review, our client then tasked us to secure the regulatory approvals and complete the project. Our services on this project include:

  • Project Planning
  • Siting Studies & Fatal Flaw Analysis
  • Market Study & Financial Modeling
  • Due Diligence (Environmental & Financial)
  • UIC Class I Permitting
  • Geochemical Compatibility Investigations
  • Local Zoning & Permitting
  • Facility Design
  • Well Workover
  • Well Testing
  • Well Startup Operation

Outcomes and Benefits

The project is successful with goals met on time and on-budget. SCS continues to play a vital role in the planning, testing, and operational maintenance of the UIC wells at the facility.

Obtained first of its kind emergency permit. SCS conducted a comprehensive review under the Illinois UIC regulatory framework and negotiated with the Illinois Environmental Protection Agency (IEPA) to finalize the technical requirements for a temporary emergency permit (the first of its kind issued in the State of Illinois) for the two Class I non-hazardous injection wells.

Successfully obtained authorizations to inject. SCS planned well workover operations to meet permitting requirements for each well and secured authorizations to inject. SCS worked cooperatively with IEPA to secure a final area permit.

Designed surface injection facilities. SCS also designed the surface injection facilities that link a newly constructed reverse osmosis (RO) treatment plant to the UIC wells and conducted in-depth chemical compatibility investigations within the RO and UIC treatment processes.