Collahuasi Mine: A Deep Dive into One of the World's Largest Copper Reserves
Located high in the rugged terrain of Chile's Tarapacá Region, the Collahuasi mine (also known as the Ujina mine) stands as a titan in the global mining industry. Situated at an altitude of 4,200 meters (13,800 ft), this massive operation represents one of the most significant copper reserves both in Chile and across the globe.
The mine is operated by Compañía Minera Doña Inés de Collahuasi, a joint venture involving Anglo American plc (44%), Glencore (44%), and Mitsui & Co. (12%). Its strategic importance is underscored by its massive scale, sitting just 15 km east of the Quebrada Blanca copper mine.
Key Facts
- Location: Tarapacá Region, Chile (20°59′29.19″S 68°38′19″W).
- Primary Products: Copper and Molybdenum.
- Estimated Reserves: 3.93 billion tonnes of ore with a 0.66% copper grade.
- 2018 Production: 560,000 tonnes of copper.
- Altitude: 4,200 meters (13,800 ft) at the mine site.
Geological Composition and Production
The ore processed at Collahuasi is rich in essential minerals. The resulting ore concentrate contains a specific blend of minerals, primarily chalcopyrite (41%), followed by chalcocite (18%), pyrite (16%), and pyrrhotite (4%).
While modern large-scale operations define its current status, the history of mining in the Collahuasi area dates back much further, with an early period of activity recorded between approximately 1905 and 1930.
Ore Concentrate Mineral Composition
| Mineral | Percentage (by weight) |
|---|---|
| Chalcopyrite | 41% |
| Chalcocite | 18% |
| Pyrite | 16% |
| Pyrrhotite | 4% |
Modern Challenges: Water Scarcity and Expansion Projects
As the mine enters the 2020s, it faces significant operational hurdles. The industry is currently grappling with water scarcity and a trend of decreasing ore grades, both of which impact profitability and sustainability.
These challenges have intersected with complex regulatory landscapes. In May 2026, the First Environmental Court of Antofagasta issued a major legal reversal by annulling a key permit (RCA) for a planned $3.2 billion expansion project. The Environmental Assessment Service is tasked with reassessing two specific components of this expansion: the desalination plant and the "human environment" (medio humano). While other parts of the project remain approved, the outcome of these reassessments is critical; if the expansion is approved in its entirety, it could delay the planned mine closure by 20 years.
Climate and Environmental Conditions
Operating at high altitudes presents extreme climatic conditions. At an elevation of 4,800 meters (15,700 ft), the climate is characterized by low temperatures and minimal precipitation. The following table outlines the mean daily temperatures and precipitation levels recorded at the site.
Climate Data for Collahuasi
| Month | Max Temp (°C/°F) | Mean Temp (°C/°F) | Min Temp (°C/°F) | Precipitation (mm/in) |
|---|---|---|---|---|
| Jan | 12.2 (54.0) | 3.5 (38.3) | -1.5 (29.3) | 5.5 (0.22) |
| Feb | 8.3 (46.9) | 1.7 (35.1) | -1.4 (29.5) | 5.1 (0.20) |
| Mar | 9.3 (48.7) | 1.3 (34.3) | -3.1 (26.4) | 2.5 (0.10) |
| Apr | 5.9 (42.6) | 0.6 (33.1) | -4.4 (24.1) | 0.0 (0.0) |
| May | 1.9 (35.4) | -2.6 (27.3) | -7.0 (19.4) | 4.5 (0.18) |
| Jun | 3.0 (37.4) | -5.9 (21.4) | -10.4 (13.3) | 0.0 (0.0) |
| Jul | 3.9 (39.0) | -4.0 (24.8) | -9.1 (15.6) | 10.0 (0.39) |
| Aug | 4.0 (39.2) | -3.3 (26.1) | -8.3 (17.1) | 2.5 (0.10) |
| Sep | 7.7 (45.9) | -2.8 (27.0) | -8.4 (16.9) | 0.0 (0.0) |
| Oct | 9.6 (49.3) | -0.9 (30.4) | -6.3 (20.7) | 5.0 (0.20) |
| Nov | 10.3 (50.5) | 0.0 (32.0) | -5.7 (21.7) | 35.1 (1.39) |
| Dec | 7.1 (44.8) | 2.5 (36.5) | -2.7 (27.1) | - |
Frequently Asked Questions
What are the primary products mined at Collahuasi?
The mine primarily produces copper and molybdenum.
Who owns the Collahuasi mine?
The mine is owned by Compañía Minera Doña Inés de Collahuasi, which is a partnership between Anglo American plc (44%), Glencore (44%), and Mitsui & Co. (12%).
What is the current status of the mine's expansion project?
As of May 2026, a key permit for the $3.2 billion expansion was annulled by the First Environmental Court of Antofagasta. The Environmental Assessment Service must now reassess the desalination plant and the "human environment" aspects of the project.
How large are the copper reserves at Collahuasi?
Collahuasi holds an estimated 3.93 billion tonnes of ore with a copper grade of 0.66%.
What environmental challenges is the mine facing?
The mine is currently facing difficulties related to water scarcity and decreasing ore grades.