OHA was formed in 1992 in response to Battle Mountain Gold Company's proposed large-scale, open-pit, cyanide-leach gold mine that would have blasted the top off Buckhorn Mountain, dug 450 feet into the aquifer that feeds five creek and dumped tailings obliterating a creek for a pick-up load of gold.

In January 2000 the project was abandoned when the Pollution Control Hearings Board reversed and vacated the water quality certification and water rights that the Washington State Department of Ecology had issued.

In February 2004, Crown Resources, a fully owned subsidiary of  Kinross Gold Corporation, submitted an Amended Plan of Operation to the regulatory agencies.  The new Plan is for an underground mine and cyanide leach mill and tailings pond with the ore transported in 100 trips down and up Marias Creek Road and the Kettle River Road to Kinross Gold formerly (Echo Bay Minerals), Key Mill near Republic.

The Washington State Department of Ecology has issued a Supplemental Environmental Impact Statement (SEIS) for the proposed mine. The Forest Service issued a final Environmental Impact Statement (DEIS) and Record of Decision for the haul road and other facilities for the proposed mine.

Ecology has approved all permits and OHA appealed many of them initiating the hearings process.

OHA and Crown/Kinross entered into negotiations resulting in an agreement whereby the mine would proceed with additional third party monitoring and stream augmentation and OHA would administer a rigorous verification of monitoring and mitigation and implement additional mitigation projects in the Okanogan Highlands.