Kilgore is an agricultural town in Clark County, Idaho, at the base of the Centennial Mountains. It is less than 60 miles west of Yellowstone National Park.

It is currently a gold exploration project owned by Canadian mining company Excellon Resources. Exploration involves drilling cores into the rock and processing them to determine how much gold exists in a claim. The company has more than 600 claims totaling more than 12,000 acres on the Caribou-Targhee National Forest.

Excellon has a permit for exploration that runs through 2026 that allows it to drill up to 420 holes at 140 sites and build up to 10 miles of new roads. It must site drill pads on roads, either existing or newly built.

Documents from Otis Gold (the previous owner) and Excellon describe an open-pit, heap-leach, cyanide mine. That means miners would tear down the mountain, crush up the ore, and soak it in a cyanide solution to separate the gold from what is known as “waste rock.” Excellon would need to process roughly 20 tons of rock for one ounce of gold.

Excellon uses the Round Mountain Mine in Nevada as an example of what Kilgore could look like. It could have several open pits, tailings ponds, and processing facilities, with trucks, lights, and workers potentially running 24/7.

Cyanide is the only economically viable processing agent for low-grade ore like the rock at Kilgore. It is used in almost all, if not all, gold mines of this type.

Though Excellon will not need to reveal final design details until it submits a mine plan, the leaching solution would likely contain cyanide. Documents from Otis Gold indicated that a cyanide leaching solution would be used, and the exploration testing has been done with cyanide processing, so it's logical to assume cyanide would be used in an eventual mine.

Public Lands: A mine would likely close public access to the site for years, removing popular off-road trails and hunting grounds from public use.

Surface water: Erosion, dust, and mining by-products could impact small streams on the site and West Camas Creek, killing fish and impacting livestock that drink from those waters.

Groundwater: West Camas Creek is in the headwaters of the Eastern Snake Plain Aquifer, which provides drinking and irrigation water to 300,000 Idahoans and powers the state’s agricultural economy. Cyanide and acid mine drainage, which can introduce toxic metals like arsenic and selenium into groundwater, could have negative impacts on the aquifer.

Wildlife: Removing ore destroys wildlife habitat by making the site uninhabitable while the mine is in operation. Dust, light, and noise pollution can impact both aquatic and terrestrial species.

The strongest permanent method of stopping a mine is to secure a congressional withdrawal, in which Congress would remove the land from “entry into hardrock mining.” If that happens, Excellon could not mine any claims that it has not proven to have a valuable mineral resource. Claims it can show have economically significant gold would be able to be mined, but hopefully it wouldn’t be enough for the company to go forward with the project.

Idaho’s federal delegation will need to support a Congressional withdrawal, so the Clean Kilgore Coalition’s work is to convince people to tell those lawmakers they oppose the mine.

In Montana, voters successfully banned new open-pit gold and silver mines that used cyanide processing in 1998 following multiple mining disasters, including a 52,000-gallon spill at the Zortman-Landusky Mine that has cost taxpayers more than $33 million to clean up.