EPA treats wastewater (acid mine drainage) coming from the Bunker Hill Mine, owned and operated by Placer Mining Co., at the Central Treatment Plant. In a few months, EPA needs to undertake upgrades to the Central Treatment Plant. During those upgrades, flows from the mine will either need to be controlled to a specific amount or completely ceased. This UAO is intended to require the owner to control and at times cease flows of wastewater out of the mine. There are also some additional conditions regarding access and O&M at the mine for previous EPA work conducted at the property.