The North Dakota Department of Mineral Resources, Geological Survey division is soliciting proposals for drilling and coring a 15 hole (15 pilot holes and up to 15 twinned core holes) in south-central North Dakota at depths typically ranging from 75 to 150 feet. Typically, the upper portion of each core hole will be drilled, and the basal 20 - 30 feet will be cored. The Geological Survey’s 2024, 53-hole drilling program identified two stratigraphic horizons of critical mineral enrichment, the Rhame bed and the Bear Den Member. These two horizons are marked by 15 to 30 feet of the white-colored clay mineral kaolinite, where the clay and any lignites in the lower portion are enriched in rare earth elements at three to ten times the proposed economic threshold. This zone is the target of the coring program and is known to contain lignites ranging in thickness from a few inches up to eight feet. Core evaluation will further document the frequency at which lignites enriched in rare earth elements and other critical minerals (e.g., gallium, germanium, etc.) occur in these zones, including their thickness and degree of enrichment, with the ultimate goal of determining if mining lignites for their critical mineral content outside of the existing coal mines is feasible with the hope that the results will encourage industry to do further exploration. The 2024 drilling program focused on the Bear Den Member while the 2025/2026 drilling program will focus on the Rhame bed.
