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Refinery Layout

RCRA Facility Investigation (RFI) Approach


The primary objectives for the proposed RFI activities are to utilize an iterative framework to collect the necessary, relevant, and targeted data to:

  • Delineate impacts of areas to be investigated

  • Evaluate potential groundwater migration pathways

  • Evaluate impact, if any, to the shallowest potable aquifer – Sunburst Formation

  • Investigate refinery on-site sewer system

  • Delineate impact from legacy refinery operations

  • Evaluate utility preferential pathways (i.e. West Rail AOC-39 to the Missouri River)

  • Characterize natural source zone depletion


RFI Phase 1 Scope of Work

  • Drill 57 Shallow Monitoring Wells

  • Drill 3 Deep Monitoring Wells

  • Conduct 59 Soil Borings

  • Conduct 104 LIF Borings

  • Abandon 16 Monitoring Wells

  • Conduct Hydraulic Slug Testing on 17 Monitoring Wells

  • Collect One Round of Groundwater Samples from 119 Monitoring Wells



Map of RFI Sampling Locations

RFI Road Map

DEQ Approves Final RFI and BRA Work Plans

2023 Q2

CMR Conducts RFI Phase 1 Investigation

2023 Q3 thru 2024 Q2

CMR Prepares RFI Phase 1 Investigation Memo and Phase 2 Work Plan

2024 Q1 thru 2024 Q4

CMR Conducts RFI Phase 2 Investigation

2025 Q2

CMR Prepares Draft and Final RFI and BRA Reports

2025 Q3 thru 2026 Q2

DEQ Approves Final RFI and BRA Reports

2026 Q3

Key: Baseline Risk Assessment (BRA​​); Calumet Montana Refinery (CMR); Department of Environmental Quality (DEQ); Quarter (Q); RCRA Facility Investigation (RIF).

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