New Report Indicates Potential for Five Times Known Copper Deposits Yet to Be Found in Central Asia

SPOKANE, Wash. — A new U.S. Geological Survey report covering major parts of the world’s largest mountain belt in central Asia estimates the existence of about five times as much copper in undiscovered deposits as has been identified to date.These areas host 20 known porphyry copper deposits, including the world class Oyu Tolgoi deposit in Mongolia that was discovered in the late 1990s.

The results of this new assessment estimate the probability that there may be as many as 97 undiscovered porphyry copper deposits within the assessed permissive tracts, which would represent nearly five times the 20 known deposits. Grade and tonnage models predict estimated resources associated with undiscovered deposits as mean values of 370,000,000 metric tons of copper, 10,000 t of gold, 7,700,000 t of molybdenum, and 120,000 t of silver. These estimated mean tonnages are predictions based on comparisons to known deposits of similar type.

Copper was one of the first metals ever extracted and used by humans, and it has been one of the important materials in the development of civilization. Because of its properties, of high ductility, malleability, and thermal and electrical conductivity, and its resistance to corrosion, copper has become a major industrial metal, ranking third after iron and aluminum in terms of quantities consumed.

USGS scientists worked in collaboration with colleagues in the China Geological Survey, the Centre for Russian and Central Eurasian Mineral Studies, and the Russian Academy of Sciences to complete the assessment. Participants evaluated applicable grade and tonnage models and estimated numbers of undiscovered deposits at different confidence levels for each permissive tract. The estimates were then combined with the selected grade and tonnage models using Monte Carlo simulations to generate probabilistic estimates of undiscovered resources.  Additional resources in extensions of deposits with identified resources were not specifically evaluated.

The full report, USGS SIR 2010-5090-X, “Porphyry Copper Assessment of the Central Asian Orogenic Belt and eastern Tethysides— China, Mongolia, Russia, Pakistan, Kazakhstan, Tajikistan, and India,” is available online and includes a summary of the data used in the assessment, a brief overview of the geologic framework of the area, descriptions of permissive tracts and known deposits, maps, and tables. A geographic information system database that accompanies this report includes the tract boundaries and known porphyry copper deposits, significant prospects, and prospects. Assessments of overlapping younger rocks and adjacent areas are included in separate reports, which are also available online.