The Grand Canyon doesn't sit on an oil field or a gold belt. It sits on breccia pipes — vertical chimneys of broken rock that happen to be some of the richest, smallest uranium deposits in North America. That geological accident has driven seventy years of mines, moratoriums, lawsuits, and a 917,618-acre national monument, and as of September 2026 it's still driving all four at once.

The short version

• Uranium around the canyon sits in breccia pipes: narrow, vertical rubble chimneys rooted in the Redwall Limestone that concentrate uranium, copper, arsenic, and lead as they mineralize over geologic time.
• A 2012 federal withdrawal pulled just over 1 million acres around the canyon out of new mining claims for 20 years — but it grandfathered in mines that already had “valid existing rights,” most notably Canyon Mine.
• In August 2023, President Biden’s Baaj Nwaavjo I’tah Kukveni National Monument made that withdrawal permanent across 917,618 acres, at the request of a coalition led by the Havasupai and Hopi tribes.
• Canyon Mine — renamed Pinyon Plain Mine — is the one operation still running. It hit groundwater in 2016, has pumped roughly 80 million gallons from its shaft since, and was producing uranium ore through 2026.
• The Havasupai Tribe has fought the mine in court since the 1980s and lost every round on the merits; in July 2026 Arizona regulators sided with the mine again, raising its allowed arsenic limit over the tribe’s objection.
• The Trump administration ordered a review of the monument in 2025, and Arizona Republicans lost their own court challenge to it in April 2026 — the legal fight over the ground itself isn’t over, even though the mine within it never stopped.

Breccia pipes: the reason any of this exists

Most of the country’s uranium comes from either sandstone deposits in the Rocky Mountain West or hard-rock veins elsewhere. The Grand Canyon region has neither in any quantity. What it has instead are breccia pipes: vertical, roughly cylindrical bodies of broken and collapsed rock, rooted in the Redwall Limestone and running upward through the rock layers for sometimes several thousand feet. They started as underground plumbing — conduits where fluids moved through the collapsing rock — and closed up over geologic time as those fluids deposited uranium, copper, arsenic, lead, and zinc inside them.

The upside, for a mining company, is grade: breccia-pipe ore can run far richer than typical sandstone-hosted deposits, which is why a 17-acre hole in the ground generates decades of regulatory fights. The downside is that a breccia pipe is also, structurally, a chimney — a pre-existing pathway connecting the surface to the aquifers below it, which is exactly the feature that turns a mining question into a water question.

From the 1950s boom to the 2012 withdrawal

The first wave of canyon-area uranium mining ran through the 1950s and 1980s, with the Orphan Mine — inside what’s now the national park itself — as the best-known example. At least eight uranium mines have operated in the wider region since. All of that activity was governed by the same 1872 Mining Law that governs hard-rock claims everywhere else in the West: stake a claim, prove it’s valid, and the federal government has very little discretion to say no.

Uranium prices spiked around 2007, and by 2010 mining companies had staked more than 10,000 new claims on public land north and south of the canyon, betting on a second boom. That triggered a federal review, and on January 9, 2012, Interior Secretary Ken Salazar withdrew 1,006,545 acres — 355,874 acres of Kaibab National Forest, 626,678 acres of BLM land, and 23,993 acres of split-estate land — from new mining claims for 20 years, to protect the canyon’s watershed while the government studied what breccia-pipe mining does to groundwater.

The withdrawal couldn’t cancel claims that already had “valid existing rights” — legal ground staked and proven before it took effect. DOI’s own analysis projected up to 11 uranium mines could still be developed under the withdrawal, versus as many as 30 if the area had stayed open. One of those grandfathered claims was Canyon Mine.

Canyon Mine becomes Pinyon Plain Mine

Canyon Mine’s paperwork predates the withdrawal by decades. The Forest Service approved its original Plan of Operations via a Final Environmental Impact Statement and Record of Decision on September 29, 1986, and the Ninth Circuit upheld that decision on appeal in 1991. When the 2012 withdrawal came through, a Mineral Validity Examination completed that April confirmed the claim’s valid existing rights under the 1872 law, exempting it from the new closure.

The mine sits about six miles southeast of Tusayan on the Tusayan Ranger District of Kaibab National Forest — Forest Service land, not park land, though close enough to the South Rim that its groundwater connects to the same aquifer system the park and the Havasupai depend on. The company later renamed it Pinyon Plain Mine. It sits roughly five kilometers from Red Butte, sacred to the Havasupai, Hopi, Navajo, and Zuni.

In 2016, shaft construction hit a perched aquifer, and the mine has been pumping water out of that shaft ever since — roughly 80 million gallons total by the end of 2025, including about 6.7 million gallons in 2025 alone. Contaminant levels in that shaft water climbed steadily against EPA drinking-water benchmarks: uranium at roughly 4 times the safe limit and arsenic at 29 times at the end of 2016, rising to arsenic at 812 times and lead at 243 times by the end of 2023 (when active ore extraction began), and reaching arsenic at 3,443 times, lead at 593 times, and uranium at 3,040 times the safe limit by the end of 2025. Those are levels in the mine’s own sump and shaft — not concentrations released into a drinking source — but they’re the numbers regulators and the tribe are watching.

Ore extraction began in January 2024. Hauling was paused, then resumed February 12, 2025, after Energy Fuels and the Navajo Nation signed an agreement governing truck routes across Navajo land. In Q1 2026, the company reported roughly 375,000 pounds of uranium in ore at 1.12% grade, with combined output from Pinyon Plain and its Utah mill complex running around 2 million recoverable pounds a year.

The 2023 monument and the fight over it

Tribal coalition leaders — with the Havasupai and Hopi at the center — spent years pushing for permanent protection rather than a withdrawal that would expire in 2032. On August 8, 2023, President Biden used the Antiquities Act to designate the Baaj Nwaavjo I’tah Kukveni – Ancestral Footprints of the Grand Canyon National Monument: 917,618 acres, jointly managed by the BLM (529,242 acres) and the U.S. Forest Service (388,376 acres), wrapped around the park’s north and south sides. The name combines Havasupai and Hopi language — “where Indigenous peoples roam” and “our ancestral footprints.”

The proclamation made the 2012 withdrawal permanent within the monument’s boundaries. It did not touch Pinyon Plain Mine, which sits in the monument’s southern parcel with rights predating the monument by decades — the same valid-existing-rights carve-out that already survived the 2012 withdrawal.

Arizona Republican legislators, Mohave County, and a rancher sued to block the monument, arguing it would cost the state uranium tax revenue and limit control over state trust land. Judge Stephanie McNamee dismissed the case on January 27–28, 2025 for lack of standing. The Ninth Circuit affirmed in early April 2026, rejecting claims of lost tax revenue, reduced land values, and future water-rights harm as too speculative, noting the underlying mineral withdrawal already runs until 2032 regardless of the monument’s fate. Arizona Senate Republicans said they’d keep pushing to unwind the monument through the Trump administration rather than the courts — and in 2025, Interior Secretary Doug Burgum had already ordered a review of national monuments, including this one, as part of a push to open federal land to energy development. As of this writing, no federal order has reduced or rescinded the monument’s boundaries.

The Havasupai position and the 2026 arsenic decision

The Havasupai Tribe’s opposition to uranium mining near the canyon goes back to the 1980s, and its legal challenges to Canyon Mine have run since the claim was first approved. The tribe, along with Grand Canyon Trust, the Center for Biological Diversity, and the Sierra Club, sued over the Forest Service’s valid-existing-rights determination; the Ninth Circuit ruled against them in December 2017.

The tribe’s objection isn’t purely about measured contamination levels. As a 2023 USGS report co-authored with a Havasupai contributor put it, the tribe’s own framework treats disruption of the aquifer itself — not just ore extraction — as a form of contamination, because Havasupai identity is bound to the water: “If the R-Aquifer becomes contaminated…we will cease to be the Havasuw baja,” people of the blue-green water.

That framework collided with regulators again in 2026. In November 2025, Energy Fuels applied to raise the allowable arsenic limit at a monitoring well near the mine by 10% and its “alert” threshold by 25%, arguing its own pumping was drawing naturally higher-arsenic water in from elsewhere in the aquifer. Arizona’s Department of Environmental Quality reclassified the request from a minor to a more significant “Other” amendment after consulting with the tribe, then approved it on July 6, 2026. Havasupai Tribal Chairwoman Melinda Yaiva called it a missed chance to side with the tribe and the state’s residents: “We cannot replace a contaminated aquifer. We cannot recreate a sacred spring.”

What’s actually off-limits (and why)

Inside the park itself, the only uranium mine site closed to the public under the Superintendent’s Compendium is Orphan Mine — shut down since 1969, fenced, and closed under 36 CFR 1.5(a)(2) for radiological and physical hazards, not ongoing mining. Pinyon Plain Mine is on Forest Service land outside the park boundary; it’s a working industrial site with its own access controls, not a park closure, and this dossier doesn’t cover its site security. The 917,618-acre national monument surrounding the park is not a closure either — it’s a mineral withdrawal that blocks new mining claims while leaving existing roads, trails, and recreation access largely as they were. For a broader map of what stops the public at Grand Canyon, see What Is Off-Limits.

Sources

1. Water resources related to breccia pipe uranium mining in the Grand Canyon region, USGS Fact Sheet 2024-3055 — U.S. Geological Survey
2. Grand Canyon Uranium Mining — Grand Canyon Trust
3. Why No Uranium Mine Is "Safe" — Grand Canyon Trust, April 2020
4. Secretary Salazar Announces Decision to Withdraw Public Lands near Grand Canyon from New Mining Claims — U.S. Department of the Interior, January 9, 2012
5. Pinyon Plain Mine (formerly Canyon Uranium Mine) — USDA Forest Service, Kaibab National Forest
6. Grand Canyon Uranium Mine Water Problem Hits 80 Million Gallons — Grand Canyon Trust
7. Energy Fuels Expects to Achieve Full-Year Uranium Production Guidance by Mid-Year — Energy Fuels Inc., June 11, 2026
8. Expanded conceptual risk framework for uranium mining in Grand Canyon watershed — Inclusion of the Havasupai Tribe perspective, USGS Open-File Report 2023-1092
9. Havasupai Tribe v. Provencio, 9th Cir. 2017 (Dec. 12, 2017)
10. Baaj Nwaavjo I'tah Kukveni Grand Canyon National Monument Established, New Uranium Mining Prohibited — Navajo Nation Office of the President and Vice President
11. Baaj Nwaavjo I'tah Kukveni – Ancestral Footprints of the Grand Canyon National Monument — Bureau of Land Management
12. New Grand Canyon Monument Doesn't Affect Uranium Supplies — Grand Canyon Trust
13. U.S. judge tosses AZ Legislature's lawsuit to stop Baaj Nwaavjo I'itah Kukveni national monument — KJZZ, January 28, 2025
14. Tribes Protect Baaj Nwaavjo I'tah Kukveni Monument (Arizona State Legislature v. Biden) — Native American Rights Fund
15. Trump's Interior Order Threatens to Open Grand Canyon National Monument to New Uranium Mining — Center for Biological Diversity, February 5, 2025
16. State's raising of arsenic limits at mine well "affects every Arizonan," tribe says — AOL/wire reporting, July 7, 2026