Natural rock drainage associated with unmined porphyry copper deposits in the Rio Grande de Arecibo watershed, Puerto Rico

The Rio Grande de Arecibo is located at the north-central part of the island of Puerto Rico; its watershed is unique because it contains most of the discovered porphyry copper deposits of Puerto Rico. Several of them were extensively explored but none were mined. The premining geochemical signature for areas around mineral deposits is essential for realistic reclamation goals at proposed mines and at abandoned mines (Runnels et al. 1998). This study represents a geochemical background characterization that can be used as a remote analogue for porphyry copper deposits in tropical climates. The characterization will be performed on the basis of the water and stream sediment geochemistry of the Rio Vivi in Utuado, which passes through the deposits, and Rio Pellejas in Adjuntas which drains the deposits. In addition to these analyses, processed images from IKONOS were used to better characterize vegetation on the vicinity of the deposits.