Idaho mine sites

Mining in Idaho leaves records in several places. The Idaho Department of Environmental Quality (DEQ) says mining activities across the state are regulated by numerous agencies and DEQ programs. DEQ's own part includes cleanup oversight at historical mine sites, preliminary assessments of abandoned mines, permits for ore processing that uses cyanide, groundwater points of compliance, and discharge permits.

In a Phase I ESA

ASTM E1527-21 does not name mine site records among its standard record sources. On a property in or near a mining area they are still worth reading, and the first job is to find which agency holds them.

• Abandoned mines are many, and assessed one at a time. DEQ says Idaho has more than 8,500 inactive and abandoned mines, mineral locations and mineral discoveries. Its reports on individual mine sites are on the Preliminary Assessment Program page.
• The lead agency may not be DEQ. In the Southern Idaho Phosphate Resource Area, DEQ says it is the lead agency at several sites, where it directs site investigations, monitoring and cleanup with other supporting agencies. It says most sites in that area are on federal land, with cleanup managed by the U.S. Environmental Protection Agency, the U.S. Forest Service or the U.S. Bureau of Land Management, and DEQ acting as a support agency. Find out which agency leads before asking for the file.
• Selenium is the phosphate concern. DEQ says the overburden removed in phosphate mining can be elevated in selenium and other potentially hazardous metals, which can accumulate in soils and vegetation or be flushed into streams and groundwater.
• Cyanide processing needs a DEQ permit. Under the Rules for Ore Processing by Cyanidation (IDAPA 58.01.13), ore processing facilities that use cyanide in mineral extraction must obtain a DEQ permit for construction, operation and closure. An applicant must collect baseline environmental data and develop operations, maintenance and monitoring plans, and submits them to DEQ as the permit application. Ask for the application when baseline data would help.
• Groundwater compliance can be measured at the edge of the mine. DEQ says the Groundwater Quality Rule (IDAPA 58.01.11) allows mine operators to request that DEQ set a point or points of compliance around the mining area, as opposed to within it. A determination sets out monitoring, sampling and reporting requirements. When reading groundwater data near a mine, check where the points of compliance are.
• Old mine water needs a discharge permit. DEQ says discharge of process wastewater from mines must be permitted, and that legacy mine discharge, including adit discharge, also requires a permit.

DEQ's Mining in Idaho page links separate pages for individual mining cleanup sites and areas. This handbook does not describe individual sites.

Where to look a site up

• DEQ's Facility Mapper page links a map tool with five categories under Mine Sites: Cyanidation permitting, General/new mining, Phosphate mines, Preliminary assessment, and Remediation action.
• DEQ's Southern Idaho Phosphate Mining page lists the sites where DEQ leads and the sites where it supports another agency, with the lead agency for each. For more information it gives the Pocatello Regional Office, (208) 236-6160.
• DEQ's Groundwater Regulations page carries a table of point of compliance determinations by location, with the date of each and a link to the document.
• DEQ's Issued Permits and Water Quality Certifications page carries a table that can be filtered by type, and Cyanidation is one of the types.

Getting the file

DEQ takes requests under the Idaho Public Records Act through its Public Records Request page, which carries buttons to submit a request online, track its status and search the request archives. Where another agency leads a site, the pages read do not say how that agency's records are requested.

Sources

Idaho Department of Environmental Quality pages, read October 1, 2026:

• Mining in Idaho, last modified April 14, 2026.
• Southern Idaho Phosphate Mining, last modified July 27, 2026.
• Preliminary Assessment Program, last modified January 7, 2026.
• Waste Management Permits and Applications, last modified June 10, 2026.
• Groundwater Regulations, last modified December 3, 2025.
• Municipal and Industrial Permits, last modified July 29, 2026.
• Issued Permits and Water Quality Certifications, last modified May 11, 2026.
• Facility Mapper, last modified January 8, 2026.
• Public Records Request, last modified August 18, 2026.