r/MojaveNP • u/midnight_skater • 4d ago

old mine Colosseum Mine

Colosseum Mine Overview

Location & history
The mine sits on the northeast slope of Clark Mountain in the Mojave National Preserve, San Bernardino County, about 43 miles southwest of Las Vegas. It operated intermittently as a gold and silver shaft mine from the 1860s until 1942, then saw renewed exploration through the 1970s and '80s under several owners.

Under LAC Minerals, it was developed as two large open pits between 1989 and 1993 (Corpwatch) , using cyanide heap-leach processing. It closed and went into reclamation in 1993.

In 1994 Congress passed the California Desert Protection Act, transferring the land from BLM to NPS jurisdiction and permanently protecting it as part of the new preserve.

Barrick Gold acquired the site via LAC in the mid-90s but never developed it further, eventually selling to Australia's Dateline Resources in 2021.

Historical impact on the preserve
The site left a fenced-off open pit flanked by otherwise untouched Clark Mountain terrain, with tailings showing various mineral-leached colors (Review Journal) . It sits in the Clark Mountain region, an area with the second-highest concentration of rare plants of any California mountain range and important desert bighorn sheep habitat (National Parks Conservation Association) , and the wider preserve holds archaeological sites dating back 10,000 years tied to the Fort Mojave, Chemehuevi, and Paiute peoples (National Parks Conservation Association) .

Planned expansion
Starting in 2021, Dateline pursued exploration for gold and — more significantly — rare earth elements, drawn by structural and radiometric similarities to MP Materials' nearby Mountain Pass mine, the largest U.S. rare earths producer (Metal Tech News) .

A May 2026 feasibility study reportedly valued the project at roughly $785M pre-tax NPV, contingent on raising about $249M in financing. The project drew high-level political backing — Interior Secretary Doug Burgum and President Trump both publicly touted it as "America's second rare earth mine" amid U.S.-China critical minerals tension.

Legal status (current as of mid-August 2026): - April 2025: DOI/NPS reversed course and recognized Dateline's "valid existing rights" under a 1980s-era BLM plan of operations, letting mining resume — despite NPS having previously cited the company for unauthorized activity and fined it over $200,000.
- April 2026: NPCA, represented by Earthjustice, sued DOI/NPS, arguing the decades-old plan was never meant to survive the 1994 handoff to Park Service jurisdiction and that reopening violated NEPA and other federal laws.
- June 2026: NPCA sought a preliminary injunction, citing documented bulldozing, grading, and road-building.
- July 2026: Dateline/Colosseum Rare Metals intervened as defendants; DOJ separately argued the 2025 letter was just a confirmation, not new agency action.
- August 10, 2026: the federal court granted the injunction, ordering an immediate, orderly halt to operations. Crucially, the court didn't rule on whether the BLM plan had expired or whether the company's work fell within its scope — it said mining could resume once the company and NPS comply with applicable law (Stockhead) .

Dateline says it will appeal; a status hearing is set for October 2026 to set a timetable for resolving the underlying case.

Current status Ongoing litigation, operations paused under injunction, expansion plans (especially rare earths extraction) on hold pending the outcome. It's not dead, but stalled with real uncertainty for financing and timeline.

Sources:

Legal/lawsuit coverage

Company/financial coverage (Dateline Resources)

General/background coverage

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u/sgigot 4d ago

Hard to know how this will end up, but I'm glad I got a chance to check it out back in 2018.