Mine operator reports steady reclamation, monitoring at Homestake and Richmond Hill sites

Nelson, a company representative for the Homestake operations, told the Board of Minerals and Environment on July 9 that reclamation work at the Homestake and Richmond Hill sites is progressing and being monitored closely.

He described recent slope repairs and revegetation at the East Waste Rock facility, showed before‑and‑after photos and said the company has increased drone use for herbicide application on steep slopes. He said geotechnical monitoring uses inclinometers, piezometers and a network of survey monuments, and that satellite interferometric synthetic aperture radar (INSAR) is used to detect millimeter‑scale surface movement. “On this image on the right, the green areas are showing essentially no displacement at all based on that satellite data,” Nelson said.

Nelson said some local soil slumping exposed waste rock on a few slopes but that repairs and revegetation have restored growth media in those areas. He cited a historic placement of nearly 1,000,000 tons of rock from underground works within the open cut under an easement granted to the Science and Technology Authority, and described a buttress installed earlier (several hundred thousand cubic yards) to stabilize a north‑end slope.

On water management, Nelson said leach pad water required ongoing treatment and reported treatment rates of roughly 30 gallons per minute, amounting to about 22,000,000 gallons treated in 2025. He said the leach pads retain an underlying liner and that water likely enters through interfaces between the clay cover and the heap leach liner.

Nelson also reviewed monitoring at Richmond Hill: he described the 2000‑era backfilling and cover system — compacted fills, a clay cap and thermal barrier — and said about 262 acres of disturbed land have been reclaimed and released from state reclamation liability, with about 75 acres still under active management. He noted the use of barrel and basin lysimeters, visual inspections and avoidance of deep‑rooting species to protect the clay cover.

Tim Comer of Dakota Gold (reporting later in the meeting) said DTRC LLC performed baseline activities at Richmond Hill and requested that permit #416 remain active through 2026 while potential future work is evaluated.

The board did not take formal action on these reports; Nelson and other presenters answered members’ questions before the meeting moved on to other agenda items.