SOCIETY OF ECONOMIC GEOLOGISTS, INC.

Special Publication, No. 15

The Challenge of Finding New Mineral Resources:

Global Metallogeny, Innovative Exploration, and New Discoveries

Volume I: Gold, Silver, and Copper-Molybdenum

EditorsR.J. Goldfarb, E.E. Marsh, and T. Monecke

Special Publications of the Society of Economic Geologists

Special Publication, No. 15

The Challenge of Finding New Mineral Resources:Global Metallogeny, Innovative Exploration and New Discoveries

Volume I: Gold, Silver, and Copper-MolybdenumR.J. Goldfarb, E.E. Marsh, and T. Monecke, Editors

First Edition, 2010

Printed byJohnson Printing

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Additional copies of this publication can be obtained from

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ISBN: 978-1-629496-33-7

SOCIETY OF ECONOMIC GEOLOGISTS, INC.

Special Publication Number 15Volume I

Table of Contents

iii

Preface Richard J. Goldfarb, Erin E. Marsh, and Thomas Monecke vii

Sponsors ix

Chapter 1The Challenge of Finding New Mineral Resources: An Introduction Richard H. Sillitoe 1

Gold

Chapter 2Global Hydrothermal Gold Resources for the Next Millennium Stephen E. Kesler and Bruce H. Wilkinson 5

Chapter 3 Chris Lodder, Ruben Padilla,Discovery History of the La Colosa Gold Robert Shaw, Timoleon Garzon,Porphyry Deposit, Cajamarca, Colombia Edwin Palacio, and Rudy Jahoda 19

Chapter 4 Richard Bedell, Eric Struhsacker, Lindsay Craig,The Pequop Mining District, Elko County, Marilyn Miller, Mark Coolbaugh,Nevada: An Evolving New Gold District Jessica Smith, and Ronald Parratt 29

Chapter 5Geology and Discovery History of the Money Knob Gold Deposit, Tolovana Mining Jeffrey Pontius,District, Eastern Alaska Russell Myers, and Chris Puchner 57

Chapter 6Portable Infrared Spectroscopy as a Tool for Alistair J.R. White,the Exploration of Gold Deposits in Tropical Vicki M. Robb, Laurence J. Robb, Terrains: A Case Study at the Damang Deposit, Ghana and David J. Waters 67

Silver

Chapter 7A Review of Silver-Rich Mineral Deposits and Their Metallogeny Frederick T. Graybeal and Peter G. Vikre 85

Chapter 8Discovery of the Juanicipio-Valdecañas Vein Zone,Western Fresnillo District, Zacatecas, Mexico Peter K.M. Megaw 119

Chapter 9The La Pitarrilla Silver-Zinc-Lead Deposit,Sierra Madre Occidental, Mexico: A Description of the Mineralization and a Reconstruction of Claire M. J. Somers,Its Volcano-Sedimentary Environment Harold L. Gibson, and Ron Burk 133

Chapter 10The Discovery History and Geology of Corani: A Significant New Ag-Pb-Zn Epithermal Andrew Swarthout,Deposit, Puno Department, Peru Marc Leduc, and Christian Rios 165

Chapter 11Discovery History of the Navidad Silver Deposits,Chubut, Argentina: A Thousand Years in the Waiting Paul G. Lhotka 181

Chapter 12Geology and Mineralization of the Navidad Ag-Pb-Cu-Zn District, Chubut Province, Argentina Dean K. Williams 203

Copper-Molybdenum

Chapter 13 J. Perelló, R. Muhr, R. Mora, E. Martínez,Wealth Creation through Exploration in a H. Brockway, T. Swaneck, J. Artal, Mature Terrain: The Case History of the Centinela C. Mpodozis, C. Münchmeyer, J. Clifford, District, Northern Chile Porphyry Copper Belt E. Acuña, D. Valenzuela, and R. Argandoña 229

Chapter 14Discovery History of a Giant, High-Grade, Hypogene Porphyry Copper-Molybdenum Vicente Irarrazaval, Richard H. Sillitoe, Deposit at Los Sulfatos, Los Bronces-Río Blanco Alan J. Wilson, William Robles, District, Central Chile Juan Carlos Toro, and Graeme Lyall 253

iv

Chapter 15The Role of Geochemistry in David L. Kelley, Chris Benn,Andean Copper Discoveries K. Brock Riedell, and Teresa Johnson 271

Chapter 16Discovery of the Kamoa Copper Deposit, Central African Copperbelt, D.R.C. D.W. Broughton and T. Rogers 287

Chapter 17Characterization and Reconstruction of MultipleCopper-Bearing Hydrothermal Systems in the Phillip A. Nickerson,Tea Cup Porphyry System, Pinal County, Arizona Mark D. Barton, and Eric Seedorff 299

v

Preface

vii

This Society of Economic Geologists Special Publication isfocused on the global challenge of finding new mineral re-sources. Metals prices have once again been on the rise dur-ing the past few years and exploration budgets continue to in-crease. But the general trend of the past several decades hasbeen continuing; there tend to be fewer new discoveries andidentification of world-class ore systems are becoming rarereach year. Many terrains and provinces with long histories ofdiscovery have reached exploration maturity. Innovative ex-ploration in these brownfields environments, as well as in lesstraditional greenfields settings, is essential to meet society’sdemands for new mineral resources.

These two volumes represent the first detailed descriptionsof many of the most important new discoveries of the past fewyears. Most papers emphasize the key characteristics of de-posits from more than a dozen countries on six continents,particularly those ores rich in gold, silver, copper-molybde-num, zinc-lead, nickel, and uranium. A key to discovery is fol-lowing the lessons learned by experienced and successful ex-plorationists; thus, a large component to the majority of thesepapers is the inclusion of the steps that were essential to find-ing new orebodies. Many of the included histories detail howconcealed mineralized zones were first identified through theintegration of good geological field work with the most mod-ern techniques in geochemistry or geophysics.

Strategies for successful exploration are dependent on athorough understanding of the correct ore deposit model.Our ideas seem to be constantly shifting on key characteris-tics that are most useful in the exploration for a specific de-posit type. Hence, this publication also includes a number ofoverview papers for each metallic commodity that summarizethe current thinking on recent advances in the metallogenicmodels for the most important deposits containing resourcesof each commodity.

These papers contain the comprehensive material used tosupport the majority of the talks presented at the SEG 2010Conference, The Challenge of Finding New Mineral Re-sources: Global Metallogeny, Innovative Exploration, andNew Discoveries, held in Keystone, Colorado, October 2–5,2010. We thank all authors for their cooperation in helping tomeet a tight deadline, yet maintaining the required high qual-ity of the papers. This deadline was only met because of thecopy editing efforts of Mabel Peterson and Alice Bouley, andlayout skills of Vivian Smallwood. Finally, all papers benefit-ted from the input of expert referees, who are listed below.

RICHARD J. GOLDFARB, ERIN E. MARSHU.S. Geological Survey

THOMAS MONECKEColorado School of Mines

Gerardo Aguirre-DiazTawn AlbinsonNick ArndtGeorges BeaudoinBarney BergerPeter BettsGeorge BreitGraeme BroadbentCharles ButtZhaoshan ChangGraham ClossDavid CookeAlvaro CróstaMichel CuneyCynthia Dusel-BaconLeandro EchavarriaBob EppingerMartin FaircloughMarco Fiorentini

Jeffrey FosterJim FranklinBruce GemmellSarah GleesonRobert GregoryDavid GrovesSusan HallJacob HanleyCraig HartDave HeberleinJeff HedenquistMurray HitzmanAl HofstraCarmen HolmgrenAlex IriondoLarry JamesDavid JohnBob KamilliKaren Kelley

Rob KerrichSteve KeslerRod KirkhamJudith KinnairdDan KontakKurt KyserVic LabsenRoss LargeDave LentzMike LesherPeter LightfootWolfgang MaierPeter MegawDan McCoyVirginia McLemoreTony NaldrettRainer NewberryConnie NuttNeil Phillips

Eric PotterHoward PoulsenKlaus SchulzGavin SelfeDave SelleyStuart SimmonsAlexandra SkewesMoira SmithJon SpencerChuck SpirakisRebecca SprouleDave SzumigalaCliff TaylorAnne ThompsonAndrew TunksPeter WormaldOzcan Yigit

Reviewers of Manuscripts

The Challenge of Finding New Mineral Resources:Global Metallogeny, Innovative Exploration,

and New Discoveries

The Society of Economic Geologists, Inc., thanks our sponsors for their generous financialsupport of the SEG Conference held October 2–5, 2010, at Keystone Resort, Colorado

PREMIER-PLUS

BRONZE

PATRON

PREMIER

FSE: GIHOTC BB: GOROOTC BB GOROR

Gold Resource Corporation

GOLD

SILVER