The May issue of Economic Geology is a special issue on the Pebble Cu-Au-Mo deposit, located near Iliamna, Alaska, edited by Karen Kelley, James Lang, and Robert Eppinger. The issue is the culmination of a multi-year, multi-disciplinary collaborative research project between the USGS and Northern Dynasty Minerals Ltd. The deposit area has been the focus of mapping and exploration since the 1950s, but the main discoveries were in the 1980 to late 1990s by Cominco (Pebble West zone), and in the mid- to late 2000s by Northern Dynasty Minerals (Pebble East zone). At present the deposit contains National Instrument 43-101 (NI-43-101) compliant measured and indicated resources total 5,942 million metric tons (Mt) at 0.42% Cu, 0.35 g/t Au, and 250 ppm Mo with an inferred resource of 4,835 Mt at 0.24% Cu, 0.26 g/t Au, and 215 ppm Mo (Kelley et al., 2013), and is the fifth largest porphyry deposit in terms of contained Cu and contains more Au than any other porphyry deposit.
The special issue covers quite a range of topics ranging from regional tectonics (Goldfarb et al., 2013), interpretation of aeromagnetics (Anderson et al., 2013), deposit geology and mineralization (Lang et al., 2013), geometallurgy (Gregory et al., 2013), alteration and infrared spectroscopy (Harraden et al., 2013), exploration geochemistry and deposit mineralogy (Eppinger et al., 2013), and Cu, Pb, Sr, and Nd isotope geochemistry of ores and surficial materials (Mathur et al., 2013 and Ayuso et al., 2013).
This issue is a worthwhile read for anyone interested in magmatic hydrothermal mineral deposits and the geology, geophysics, geometallurgy and exploration for porphyry Cu-Au-Mo deposits.