Remote Sensing Analyses for the Collahuasi Mine

Satellite imagery analysis is a cost-effective method for tracking environmental changes over large areas — and long periods — in areas where ground access is impractical. We used this method at Collahuasi to establish baseline conditions and to monitor changes in surface water and vegetation over time.


The Collahuasi Mine is located within the Coposa and Michincha basins — an extremely arid, ecologically sensitive area of Chile that lies at an elevation of about 4,400 meters (14,400 feet) above sea level. The estimated groundwater demand for this mine is about 1,000 liters per second.


  • Analyzed 28 Landsat 5 satellite images for the period February 1986 – July 2005 for the Salar de Coposa, Salar del Huasco, and Salar de Michincha basins
  • Selected high-quality, cloud- and noise-free images; georeferenced them to facilitate comparison; and corrected them for differences in sun angle, satellite position, and atmospheric haze
  • Determined the vegetation and surface water areas and assigned vegetation indexes (abundance and health)
  • Compared results for basins with and without groundwater pumping
  • Identified potential correlations with precipitation and groundwater pumping
  • Developed a satellite image monitoring system to establish an historic environmental baseline for surface water and vegetation within the region’s salar basins