Dakota Gold Completes Key Studies for Richmond Hill Gold Project

Dakota Gold Corp., a South Dakota-based exploration and development company, has announced key advancements in its Richmond Hill Oxide Heap Leach Gold Project. The company has completed crucial process and site-layout trade-off studies for the upcoming Pre-Feasibility Study (PFS) and has received the final assay results required for the Richmond Hill PFS resource update.

According to Jack Henris, Chief Executive Officer, President, and Director of Dakota Gold, the completion of these studies and assays marks significant progress in defining the resource model, process design, and infrastructure configuration for the Richmond Hill project.

The studies have led to the selection of a 0.5-inch (12.7-millimeter) design crush size and a single heap-leach facility located within the area identified for Phase 1 in the Initial Assessment with Cash Flow (IACF). These decisions reflect favorable metallurgical recovery results and will simplify operations and reduce geotechnical and execution risk relative to a multiple-facility configuration.

The PFS trade-off evaluation of the primary crushing options has indicated that modeled ultimate gold recovery for oxide material averaged 80.4% at a 0.5-inch crush size, compared with 75.9% at a 1-inch crush size. The PFS financials will capture this benefit when it is released later this year.

The updated resource informing the PFS will incorporate 333 drill holes completed in 2025 and 2026, representing 30% more drilling data from the prior resource, and will be entirely focused on oxide material. The metallurgical test program results defined oxide material as having a CN/FA ratio ≥0.82 and total sulfur content ≤0.5%. Therefore, the PFS will exclude transition material, which represented roughly 18% of the heap leach material in the prior resource.

The Company has also selected a single heap-leach facility located generally within the area identified for Phase 1 in the IACF, rather than the multiple conceptual heap-leach areas previously considered. The consolidated configuration will simplify material handling and solution management, optimize operations, and consolidate the geotechnical design and monitoring program within one operational area.

Dakota Gold is currently operating with two drills to convert additional inferred resource material to reserve category post-PFS into a FS mine plan. A portion of this drilling is dedicated to producing additional samples to complete the FS level of metallurgical variability testing across the dominant lithologies and geo metallurgical domains. The FS is expected to be published mid-2027.

In addition, the Company has received 3,002 meters (9,847 feet) of geotechnical drilling conducted after the PFS drilling was completed, as well as Chism Gulch phase 2 definition drilling designed to convert remaining inferred blocks for the FS. This round of metallurgical variability testing is in direct support of the FS and meets the requirements for adequate statistical representation of material types and quantities in the plan at the FS level.

The metallurgical variability testing scope includes new metallurgical hole core logging and sample preparation, head sample compositing and characterization, bottle-roll testing, column testing (60-day fixed interval) on 30 to 40 master-composite columns across geometallurgical domains and 4 primary lithologies, select tails deportment as necessary, ABA geochemistry, acid mobility testing and modeling, and sulfide reactivity, standard preg rob suite, mercury solution balance, zinc precipitation performance mapping, geotechnical testing on column tails - compact permeability, direct shear, LA abrasion, and slake durability testing.

Dakota Gold is excited to include the completed assay dataset in the upcoming PFS. The updated model will also incorporate the results of the recent metallurgical program, including the strong recovery response from breccia-hosted oxide material, to support recovery assignment, ore routing, and mine-sequencing decisions.

The Company's Maitland Gold Project has also seen initial drill results, representing 791 meters (2,594 feet) of drilling from the 5,578-meter (18,300-foot) campaign to produce a maiden resource for the Tertiary epithermal Unionville Zone. In response to the strong metallurgical results from breccia-hosted oxide material at Richmond Hill, Dakota Gold redirected drilling capacity to the central Richmond Hill area to prioritize definition and metallurgical drilling that can inform Feasibility Study mine sequencing and resource conversion opportunities.

Dakota Gold is committed to advancing the Richmond Hill Gold Project toward production as soon as 2029, while continuing to define and expand the high-grade underground gold resource potential at the Maitland Gold Project. Both projects are located on private land within the historic Homestake District of South Dakota, one of the most prolific gold mining regions in the United States.