Dakota Gold Corp. has completed its pre-feasibility study metallurgical test program for the Richmond Hill Oxide Heap Leach Gold Project in South Dakota, reporting positive gold extractions of up to 92.0% from master-composite column tests.

The testing program evaluated 24 master-composite column tests across principal lithologic, grade, and oxidation domains at crush sizes of 0.5 inches and 1 inch, with leach times running from 21 to 47 days. Twelve oxide column tests delivered gold extractions ranging from 57.3% to 92.0%, yielding an unweighted arithmetic average of 74.2%. Breccia oxide material recorded the strongest response, with gold extractions reaching between 90.7% and 92.0%.

Modeled ultimate recovery means for oxide material reached 80.4% at a 0.5-inch crush size compared with 75.9% at a 1-inch crush size. Testing identified no discernible issues with compact permeability, clay material, or preg-robbing characteristics that would hinder operational performance. Crush-size trade-off studies remain active to evaluate the recovery benefit of the finer 0.5-inch crush against crushing, conveying, and operating costs.

To support mineral reserve conversion for the upcoming feasibility study, Dakota Gold has commenced a definition and metallurgical drill program in the central project area. The campaign will complete approximately 3,800 meters of metallurgical drilling and 11,000 meters of definition drilling through 2027.

“We are pleased to have completed our comprehensive metallurgical test program for our PFS, a key step in our process to systematically de-risk the Project through disciplined and detailed technical studies for the responsible development of Richmond Hill. The PFS metallurgical test program results support the conversion of Richmond Hill's geological variability into a practical recovery model for mine planning and process design. Separating oxide from transition material performance gives the Company a clearer basis for recovery assignment, mine sequencing, ore routing, and process optimization. The strong breccia-hosted material recovery response and the defined crush-size trade-offs are important inputs to selecting a technically-sound, capital-efficient, heap leach flowsheet.”

— Jack Henris, CEO, President and Director

Dakota Gold expects to complete the pre-feasibility study for Richmond Hill in the fourth quarter of 2026, with the feasibility study scheduled for publication in mid-2027.

Read the full announcement: Dakota Gold Reports Positive Metallurgical Test Program Results Informing the Richmond Hill Pre-Feasibility Study