Advancing Science and Discovery

SEGJANUARY 2013ABSTRACTAn increasing number of mineral discoveries rely on remote sensing methods such as airborne geophysics and hyperspectral imaging. The relatively new technology of Light Detection and Ranging (LiDAR), whereby surface outcrop patterns suggestive of economic mineralization can be identified, has the potential to join other remote sensing techniques employed by the exploration geologist. Successful application of LiDAR relies on rigorous, high-quality data collected under strict QA/QC standards and is most useful for delineating linear features such as faults or resistant rock types such as silicification. If used judiciously, LiDAR can join the toolbox of the modern exploration geologist working in heavily vegetated areas that contain many of the most prospective terrains left on Earth.Corresponding author: e-mail, paul.jewell@utah.edu

NEWSLETTERwww.segweb.org

NUMBER 92

Rediscovering the Discovery Outcrop: The Promises and Pitfalls of LiDAR Technology in Mineral ExplorationINTRODUCTIONFinding new ore deposits has traditionally relied on careful field work by professionals or the serendipitous realization of prospectors that a particular rock outcrop possessed valuable minerals or the alteration indicating nearby mineralization. The discovery outcrop has thus been part of the beginning of many large mineral districts and has appeared in the narrative of mineral discoveries as recently as the 1970s and 1980s (e.g., Williams et al., 2000; Borg et al., 2003). In mid- and high-latitude terrains, rock outcroppings are often readily visible, meaning ore deposits close to the Earths surface in these areas had largely been discovered by the close of the past century. The latter part of the 20th century saw increased reliance on geophysical methods and deep drilling to find ore deposits in sparsely vegetated terrains of mid and high latitudes as to page 14 . . . well as expanding

Cour ses, Upco For m See New ing Sho Sect rt ion, p. 4 8

Paul W. Jewell, (SEG 2001) J. Anna Farnsworth, and Theresa Zajac, Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112

FIGURE 1. Location of the mineral districts discussed in the paper (Alta, Frisco, and North Santiam) that have been imaged with LiDAR.

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JANUARY 2013 No 92

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ContentsF E AT U R E A R T I C L E

NEWSLETTERN 92 JANUARY 2013EXECUTIVE EDITOR

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Rediscovering the Discovery Outcrop: The Promises and Pitfalls of LiDAR Technology in Mineral Exploration From the Executive Director: SEG Council Actions Presidential Perspective: Just a Matter of Time/Solo una cuestin de tiempo SEGF Presidential Perspective: The SEGF Field Course Program: A Continuing Endeavor Society of Economic Geologists Awards 20122013 Contributions SEG, SEG Foundation, and SEG Canada Foundation SEG Geometallurgy Forum Announcing the SEG 2013 Distinguished Lecturer Announcing the SEG 2013 Traveling Lecturers SEG Awards Dinner, Lima, Peru SEG 2012 Conference in Lima, Peru XVI Peruvian Geological Congress Bolivian Geological Congress Celebrates 50 Years of CGB SEG Distinguished Lecturing in 2012 Richard H. Sillitoe Lectures to Students Erratum: October 2012 SEG Newsletter Summary of Economic Geology Papers Published in 2012 Student Chapter Grant Recipients for 2012 SEG Students Committee 2013 Student Chapter Support Available: SEG Stewart R. Wallace Fund Welcome New Student Chapters Announcing the 2013 PDAC-SEG Student Minerals Colloquium SEG Foundation Graduate Student Fellowships Announcement SEG Foundation Student Research Grants Announcement Student-Dedicated Field Course Southern Peru Porphyry Systems SEG Foundation Student-Dedicated Field Course: Preliminary Announcement Universit Laval SEG Student Chapter Field Trip University of Toronto SEG Student Chapter Field Trip University of New Brunswick SEG Student Chapter Field Trip Munich SEG Student Chapter Field Trip

NEWSLETTER COLUMNS4 8-9 10 5 12-13 19 20 20 22-23 24-25 26 27 28 28 29-32 34 34 35 35 36 36 37 38 39 41 41 42 42

Brian G. HoalPRODUCTION MANAGING EDITOR

SEG NEWS

Chris BrandtNEWS EDITOR

Alice BouleyGRAPHIC DESIGN

Vivian SmallwoodADVERTISING & ANNOUNCEMENTS

Christine HorriganSociety of Economic Geologists, Inc. 7811 Shaffer Parkway Littleton, CO 80127-3732 USA Tel. +1.720.981.7882 Fax +1.720.981.7874 E-mail: seg@segweb.org

WEBSITE

SEG STUDENT NEWS

www.segweb.orgFeature articles are peer reviewed before they are accepted for publication. Please submit material to the Executive Editor. Tel. +1.720.981.7882 Fax +1.720.981.7874 E-mail: director@segweb.orgThe SEG Newsletter is published quarterly in January, April, July, and October by the Society of Economic Geologists, Littleton, Colorado, exclusively for members of the Society. Opinions expressed herein are those of the writers and do not necessarily represent ofcial positions of the Society of Economic Geologists. When quoting material from the SEG Newsletter please credit both author and publication. 2013 The Society of Economic Geologists, Inc. Printed by MODERN LITHOPRINT CO. Jefferson City, Missouri SEG Newsletter non-receipt claims must be made within four (4) months [nine (9) months outside of the U.S.A.] of the date of publication in order to be filled without charge.

E X P L O R AT I O N R E V I E W S44 Alaska 44 Australasia 45 Mexico 45 Northern Eurasia 46 Contiguous United States

MEMBERSHIP49-52 53 56 7 10 11 28 40 40 43 47 47 54-55 48 60 582 59 43 43 35 35 50 21

SEG Membership: Candidates and New Fellows, Members, and Student Members Officers and Committees Personal Notes & News Rio Tinto - SEG Special Publication: A Tribute to Richard Sillitoe Economic Geology Anniversary Collection DVD Now Available! Geofacets from Elsevier and SEG Ore Deposits of the Andes DVD FUTORES 2013 Noel White Symposium on Ore Deposits, Townsville, Australia Latin American Geosciences Student Conference, Medelln, Colombia Metamorphism in the Ore Environment Special Session & Field Trip at GAC-MAC 2013 SEG 2014 Conference Building Exploration Capability for the 21st Century GSSA GeoForum 2013 - Johannesburg, South Africa SEG-SEG Canada Foundation Whistler 2013: Geoscience for Discovery SEG Orogenic Gold Course at the SEG Course Center, Littleton, Colorado USA SEG Ni-Cu-PGE Course at PDAC 2013 -Toronto, Canada (back cover) Calendar2 21 33 59 58 56 52 57 Geosense (inside front cover) Intl Applied Geochemistry Symp. io global Kinross Gold (inside back cover) Laravie, Joseph A. Logemin LTL Petrographics Ore Research & Exploration 35 52 56 2 50 58 33 40 Petrographic Consultants Intl. Recursos del Caribe, S.A. Resource Geosciences de Mexico SGS (inside front cover) Sims, Dale Shea Clark Smith UWA Job Opportunity Zonge Engineering & Research

ANNOUNCEMENTS

FOR CONTRIBUTORS The SEG Newsletter is published for the benet of the worldwide membership of the Society of Economic Geologists. We invite news items and short articles on topics of potential interest to the membership. If you have questions on submittal of material, please call the SEG ofce at +1.720.981.7882 or send details by FAX to +1.720.981.7874; by e-mail to publications@segweb.org Format: E-mailed news items should be 5 Mb maximum. Send to publications@segweb.org. Short items may be faxed. Please include your name and contact information for verication purposes. Please e-mail Chris Brandt at the above address if you have questions. Advertising: Paid advertising is solicited to help offset publication and mailing costs; for rates, contact ChristineHorrigan@segweb.org.

S E G E D U C AT I O N & T R A I N I N G C U R R I C U L U M

CALENDAR OF EVENTSADVERTISERS Actlabs, Ltd. (inside front cover) ALS Minerals (inside back cover) Anzman, Joseph R. AVRUPA Minerals Big Sky Geophysics de Haller & Schmidt Geocon, Inc. AIG/Geoscientists Symposia

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February 28, 2013

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SEG NEWSLETTER

No 92 JANUARY 2013

FROM THE EXECUTIVE DIRECTOR

SEG Council Actions Westin Hotel and Convention CenterLima, Peru September 22, 2012The SEG Council held a regularly scheduled meeting at the Westin Hotel and Convention Center in Lima, Peru. Members of the Council present were L. Fontbot (Chair), A. Arribas, R., G.M. Brown, M. Cardozo, M.S. Enders, R.J. Goldfarb, B.G. Hoal, K.D. Kelley, J.A. Kinnaird, and Y. Watanabe. C.A. Horrigan (SEG Executive Assistant) and A. Crosta (Regional VP for South America) also attended. Apologies were received from J. Gutzmer, A.C. Harris, T.C. McCuaig, P.K.M. Megaw, H.J. Noyes, G.R. Olivo, M.T. Smith, and A.S. Yakubchuk. President Fontbot called the meeting to order at 1:38 p.m. After establishing that there was a quorum, President Fontbot noted several changes in the agenda to ensure earlier discussion of the Traveling Lecturer Program, the nature and structure of SEG-organized conferences, and the Education and Training Curriculum. The following actions were taken at the meeting: Approved a motion from Enders to accept the minutes of the meeting held on March 3, 2012. Passed a motion from Enders to accept the report of the Vice President for Regional Affairs as presented by Y. Watanabe and the following specific actions: Approved a motion from Watanabe to appoint Mei-Fu Zhou (University of Hong Kong) and Evgeny Naumov (Russian Academy of Science) as the 2013 Regional Vice Presidents for Asia and North Eurasia, respectively. Requested guidelines for Traveling Lecturers from Watanabe to ensure that these individuals could be deployed as effectively as possible on behalf of the Society. Approved the subcommittee (Chair: D.L. Huston) recommendation of Stephen J. Turner (SEG 1993 F) from Newmont Asia Pacific, Australia, as the 2013 International Exchange Lecturer. Approved the subcommittee (Chair: B. Rusk) recommendation of Jose Perello (SEG 1989 F) from Antofagasta Minerals, Chile, as the 2013 Thayer Lindsley Visiting Lecturer. Approved the subcommittee (Chair: Watanabe) recommendation of Nicholas Arndt (Fellowship pending) from the University of Grenoble, France, as the 2013 Regional Vice President Lecturer. Lecturer Program to address growing demand from members, student chapters, BRIAN G. HOAL and conference SEG Executive Director organizers. If apand Editor proved, the process for the selection of lecturers would be determined by the SEG Executive Committee, with experience and competence as key criteria. Passed a motion from Fontbot to accept the report of Past President Enders on the Program Committee and the following key actions: Thanked Miguel Cardozo for his role in ensuring a highly successful conference in Lima, Peru, as SEG 2012 Meeting Coordinator. Noted the future need to have all talk and poster presenters register early for a conference. Discussed the format and frequency of future SEG conferences, recognizing the need for increased administrative oversight from staff, a template for conducting such meetings (e.g., parallel sessions), and the need to anchor more opportunistic regional meetings (in principle, one per year with another organization) to the quadrennial stand-alone Keystone conference in the USA. Agreed that regional meetings/conferences could take place in any given year, provided there is no conflict with other SEG-sponsored events. Decided to add another year to the current program calendar to extend activities to 2016, thereby providing a 5-year look forward on a rolling basis. Passed a motion from Enders to accept the Education and Training Committee Report as compiled by Elizabeth Holley, Program Coordinator, and presented by the committee Chair, Antonio Arribas. The following points were noted: At least twenty courses were scheduled or under consideration for 2013, most likely more with the

Requested that President-Elect Arribas and incoming President-Elect Kinnaird schedule a teleconference with the Vice President for Regional Affairs and the seven Regional Vice Presidents prior to the next Council meeting. On a recommendation from the SEG Executive Committee, passed a motion from Enders to request that SEG Foundation fund a new SEG Visiting

Boost Your Rsum Upgrade to Fellow!Increase your status at no cost and help the SEG at the same time. Benets of Fellowship Put the SEG Fellow designation on your rsum Sponsor other professionals to join the Society Become involved in SEG governance by serving on a committee or standing for election Eligibility Requirements Nominee should have a minimum of eight years of professional experience, including not less than ve years of work principally devoted to economic geology, three of which must have been in positions of responsibility. Consideration will be given to work of an individual in research or as a teacher of economic geology. Download application form at www.segweb.org/forms/Fellowship-Application-Form.pdf. Two SEG Fellows to serve as primary and secondary sponsors SEGs Goal With a greater pool of Fellows, SEG can increase the diversity of its leaders, better meet the needs of members in all locations, and evolve into an organization truly representative of its varied components.

NEW REVISED, FILLABLE Fellowship Form now available at http://www.segweb.org/pdf/forms/Fellowship-Application-Form.pdf

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Whistler conference in September. Courses conducted to date in 2012 had benefited from the hiring of a part-time Program Coordinator, with surveys being conducted after each course and feedback helping to refine courses in terms of marketing, timing, duration, and content. The objective for 2013 was to produce a downloadable prospectus or brochure of courses that could be updated regularly. On a structural basis, there was a need for the Education and Training Committee to retain the involvement of Short Course and Field Trip Coordinators independent of the Program Coordinator. Approved a motion from Kinnaird to ratify the following actions taken by the Executive Committee since its meeting on March 2, 2012: Approved Fellowship List No. 1201 on March 10, 2012, thereby admitting the following 16 candidates to SEG Fellowship: Alice M. Clark, Yana Fedortchouk, Craig S. Finnegan, Elmer J. Flores, Giovanni Funaioli, Christopher J. Gregory, Khurelbaatar Lamzav, Nicholas G. Leboutiller, Stuart R. McCracken, Miguel A. Manrique, Erin E. Marsh, Pavel Reichl, David Selby, Dale A. Sims, David S. Smith, and Perumala V. Sunder Raju. Approved on March 26, 2012, the draft Executive Committee minutes for the March 2, 2012, meeting held at the Radisson Admiral Harbourfront Hotel in Toronto, Canada. Approved Fellowship List No. 1202 on June 6, 2012, thereby admitting the following 12 candidates to SEG Fellowship: Michel Bonnemaison, Brian Brewer, Emmanuel John M. Carranza, Kurt C. Friehauf, Matthew D. Gray, Paul D. Harbidge,

Sean M. Hasson, Klaus Heppe, Mark J. Lindsay, Colin F. Moorhead, Alan L.E. Simmonds, and Phillips C. Thurston. Recommended on July 10, 2012, that Council approve the nomination of the following members to Honorary Fellow status: Shunso Ishihara, Ronald E. Seavoy, Ulrich Petersen, and Roy Woodall. Approved Fellowship List No. 1203 on September 6, 2012, thereby admitting the following 19 candidates to SEG Fellowship: Stephen W. Beresford, Maurice Colpron, Martin Doyle, Leandro E. Echavarria, Timothy A. Fletcher, Rodney W. Graham, Timothy W. Gray, Philip J. Hancox, Alan J. Hawkins, Quinton T. Hennigh, Jaromir Leichmann, Tim K. Lowenstein, Gerardo R. Matos Salinas, Kevin W. McNulty, Strashimir B. Strashimirov, Andrew J. Tunningley, Daramjav Turmagnai, Michael J. Woodbury, and Roberto P. Xavier. And the following actions taken by the Council since its meeting on March 3, 2012: Approved on April 17, 2012, the draft Council minutes for the March 3, 2012, meeting held at the Radisson Admiral Harbourfront Hotel in Toronto, Canada. Approved on April 30, 2012, six new and one reactivated student chapter applications. The new student chapters include the Guangzhou Institute of Geochemistry (GIG) Student Chapter, China; Indiana University Student Chapter, Indiana, USA; Munich Student Chapter (joint chapter to include LMU-Ludwig-Maximillian Universitt and TUM-Technische Universitt), Germany; Universidad Nacional de San Agustin Student Chapter, Peru; UFRGS Federal University of Rio

Grade do Sul, Brazil; and the Vision for Geosciences in Bolivia at the Universidad Mayor de San Andres, Bolivia. The University of Oregon/Oregon State University Student Chapter, Oregon, USA was reactivated. Approved on May 10, 2012, the recommendation of the Economic Geology Editorial Board that the Brian J. Skinner Award for 2011 be presented to Ross R. Large for his paper with Stuart W. Bull and Valery V. Maslennikov, A carbonaceous sedimentary source-rock model for Carlin-type and orogenic gold deposits, v. 106, no. 3, p. 331358. Approved on June 21, 2012, the Nominating Committees slate of candidates to take office in the period 20132015: Judith A. Kinnaird, 2013 President-Elect; Jean S. Cline, Councilor; Francisco I. de Azevedo, Jr., Councilor; and Thomas Monecke, Councilor. Passed a motion from Enders approving the appointment by President Fontbot of Stephen J. Piercey as the 2013 SEG Councilor replacement for Judith A. Kinnaird. Passed a motion from Enders accepting the report of the Executive Director. Key highlights were the record membership at 6,746 (19% being students), continuing growth in membership and activities outside North America, including a record number of student chapters (68), successful launch of the Education and Training curriculum, and introduction of several digital initiatives including mobile access to Economic Geology, social networking, and Geofacets. Passed a motion from Kinnaird accepting the report of the Foundation President (in absentia) and noting the proposed candidates for the 2013 Foundation to page 6 . . . Board of Trustees:

Society of Economic Geologists Awards 20122013Robert O. Rye (US Geological Survey, USA) R.A.F. Penrose Gold Medal for 2012 Jos Perell (Antofagasta Minerals SA, Chile) SEG Silver Medal for 2012 Allan P. Juhas (Consultant, USA) Ralph W. Marsden Award for 2012 Martin M. Reich (Universidad de Chile, Chile) Waldemar Lindgren Award for 2012 Anthony E. Williams-Jones (McGill University, Canada) SEG Distinguished Lecturer for 2013 Stephen J. Turner (Newmont Asia Pacific, Australia) SEG International Exchange Lecturer for 2013 Jos Perell (Antofagasta Minerals SA, Chile) SEG Thayer Lindsley Visiting Lecturer for 2013 Nicholas T. Arndt (University of Grenoble, France) SEG Regional VP Lecturer for 2013

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SEG Council Actions Westin Hotel and Convention Center (Continued)

Stuart McCracken, David Kelley, and Ruth Carraher. This slate had been approved prior to the Council meeting by all Councilors (the members of SEG Foundation), because only four Councilors were able to attend the meeting in Lima. Council further noted that William X. Chavez and Andrew Swarthout would become Foundation President and Vice President, respectively, in 2013. Passed a motion from Kinnaird to approve the Treasurers Report, specifically the financials for the period January 1 to July 31, 2012, as presented by the Executive Director. On a motion from Cardozo, approved the 2013 budget proposed by the Budget Committee and presented by the Executive Director. Passed a motion from Enders to approve the request that an additional

Attention SEG Members: Special Presentation at PDAC 2013Dr. Sillitoe will give a presentation, A decade of discovery in the Southern Andes, at 1:10 pm on Sunday, March 3, 2013, at the New Mines in the Central Andes session of the PDAC technical program, which will include a presentation of the volume by Stephen McIntosh, Head of Exploration for Rio Tinto plc.(Metro Toronto Convention Centre, Level 700, South Building, Toronto, Canada).

bank account be opened at the Colorado Business Bank. Passed a motion from Enders to ratify the Investment Committee membership for 2013 as follows: G. Ireland (Chair), D. Baker, R. Hall, C. Herald, B. Putnam, B. Suchomel, H. Noyes, and B. Hoal. Passed a motion from Arribas accepting the report of the Chair of the Publications Board, Goldfarb. Noted the reappointment for the Editor, Lawrence Meinert, and the need to move into online publishing to improve turnaround of author manuscripts. Less expensive journal printing options were being investigated, including offshore, and trials were scheduled to take place in 2013. A number of new publications were in the pipeline and partnership with Elsevier would bring the map-based interface, Geofacets, to members and institutional subscribers alike. On a motion from Fontbot, approved the committee (Chair, C. de Ronde) recommendation of Anthony E. Williams-Jones (F 90), McGill University, Canada, as the 2013 SEG Distinguished Lecturer. On a motion from Arribas, approved the Awards Committee (Chair, A. Yakubchuk) recommendations as follows: Penrose Gold Medal for 2012 to Robert O. Rye (F 74), U.S. Geological Survey, USA SEG Silver Medal for 2012 to Jose Perello (F 89), Antofagasta Minerals, Chile Ralph W. Marsden Award for 2012 to Allan P. Juhas (F 79), Lakewood, CO, USA Further noted the need for the Chair of the Awards Committee to take particular care to ensure that all Councilors voted in a timely fashion, engaged in adequate information exchange and, finally, voted for all candidates to ensure accurate ranking. Passed a motion from Enders to approve the recommendation of the committee (Chair, L. Meinert) that Martin M. Reich (M 11), Universidad de Chile, receive the 2012 Waldemar Lindgren Award. Discussed the SEG Honorary Fellow Committee Report presented by Enders and, on a motion from Fontbot,

reaffirmed Honorary Fellowships for the following nominees: Shunso Ishihara (SF 78), Geological Survey of Japan Ulrich Petersen (LF 64), Massachusetts, USA Ronald E. Seavoy (M 01), Ohio, USA Roy Woodall (SF 83), Earthsearch Consulting, South Australia SEG Honorary Fellows are senior economic geologists recognized for extraordinary contributions, particularly those who have not already received an SEG Medal or Award. On a motion from Goldfarb, approved the following nominees for committee vacancies as recommended by the Committee on Committees (Chair, R. Lipson): Distinguished Lecturer Committee: Dave Cooke, Noel White, and Larry Cathles Fellowship Admissions Committee: Ross Large Lindgren Award Committee: Tim Baker and Mark Barton Student Affairs Committee: Anthony Williams-Jones Passed a motion from Enders to accept the report of the Student Affairs Committee submitted by the Chair, A. Harris, and noted the following: There are currently 68 Student Chapters located in 25 countries. Recommendation for a new SEG Student Chapter at Masaryk University, Czech Republic The SEG Stewart R. Wallace Fund distributed $24,987 as part of Round 1 (of 2) funding. The Students Committee representative should be present at the next meeting of the SEG Council to resolve, in particular, a succession plan. President Fontbot thanked the SEG staff for their support of the Council and Past President Enders for the significant changes that had taken place during his tenure on Council. Agreed to schedule the next meeting of the Council on Saturday, March 2, 2013, at the Radisson Admiral Harbourfront in Toronto. Adjourned the meeting at 6:05 p.m. on a motion from Fontbot. 1

Rio Tinto Exploration is sponsoring this SEG publication, dedicated to Richard H. Sillitoe in recognition and appreciation of his contributions to the understanding of the worlds major copper districts.Visit the SEG booth (#718) at PDAC 2013, March 36, for information on availability and purchase.

For SEG Special Publication 16 details, see announcement on adjacent page.

JANUARY 2013 No 92

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ble in Availaarch 2013 M

into io T R

SEG Special Publicat

ion 16

SEGwww.segweb.org

Geology and Genesis of Major Copper Deposits and Districts of the World: A Tribute to Richard H. SillitoeJeffrey W. Hedenquist, Michael Harris, and Francisco Camus, Editors

Contents with First AuthorsGeology and mineralogical zonation of the Olympic Dam iron oxide Cu-U-Au-Ag deposit, South AustraliaK. Ehrig (BHP Billiton) et al. Geology of the Tenke-Fungurume sediment-hosted stratabound copper-cobalt district, Katanga, Democratic Republic of CongoW. Schuh (Freeport) et al. Dzhezkazgan and associated sandstone copper deposits of the Chu-Sarysu basin, central KazakhstanS.E. Box (U.S. Geological Survey) et al.

Premier provincesCenozoic tectonics and porphyry copper systems of the Chilean AndesC. Mpodozis & P. Cornejo (Antofagasta Minerals) The southwestern North America porphyry copper province R. Leveille & R. Stegen (Freeport) Tectonomagmatic settings, architecture, and metallogeny of the central Asian copper provinceA. Yakubchuk (Orsu Metals) et al. The iron oxide copper-gold systems of the Carajs mineral province, BrazilR.P. Xavier (UNICAMP) et al. An overview of the European Kupferschiefer depositsG. Borg (Halle University) et al. The Central African Copperbelt: Diverse stratigraphic, structural, and temporal settings in the worlds largest sedimentary copper districtM. Hitzman (Colorado School of Mines) et al.

Bingham Canyon

IntroductionCopper provincesR. Sillitoe (London)

Major depositsUpdate of the geologic setting and porphyry Cu-Mo deposits of the Chuquicamata district, northern ChileS. Rivera (CODELCO) et al. Geologic overview of the Escondida porphyry copper district, northern ChileM. Herv (Minera Escondida Ltda.) et al. Geologic setting and evolution of the porphyry copper-molybdenum and copper-gold deposits at Los Pelambres, central ChileJ. Perell (Antofagasta Minerals) et al. Protracted magmatic-hydrothermal history of the Ro BlancoLos Bronces district, central Chile: Development of worlds greatest known concentration of copperJ.C. Toro (Anglo American), P. Cuadra (CODELCO) et al. Geology of the Bingham Canyon porphyry Cu-Mo-Au deposit, UtahJ.P. Porter (Rio Tinto) et al. Geology and exploration progress at the Resolution porphyry Cu-Mo deposit, ArizonaC. Hehnke (Resolution Copper Company) et al. Magmatic-hydrothermal-structural evolution of the giant Pebble porphyry Cu-Au-Mo deposit with implications for exploration in southwest AlaskaJ.R. Lang (HDI Mining) & M.J. Gregory Geologic overview of the Oyu Tolgoi porphyry Cu-Au-Mo deposits, MongoliaD. Crane & I. Kavalieris (Ivanhoe Mining) Copper-gold molybdenum deposits of the Ertsberg-Grasberg district, Papua, Indonesia C. Leys (Freeport) et al.

Genetic themesCopper-rich magmatic Ni-Cu-PGE depositsD.R. Burrows (Vale) & C.M. Lesher Magmatic controls on porphyry copper genesisA. Audetat (Univ. Bayreuth) & A.C. Simon Hydrothermal controls on metal distribution in porphyry Cu (-Mo-Au) systemsK. Kouzmanov (Univ. Geneva) & G.S. PokrovskiOyu Tolgoi

Archived SEG papers by R.H. Sillitoe included on CD-ROMPhotos courtesy of Rio Tinto

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SEG NEWSLETTER

No 92 JANUARY 2013

PRESIDENTIAL PERSPECTIVE

Just a Matter of TimeWe can say with confidence that our Society is doing well. A few of our strengths include the following: a) our finances are sound; b) the flagship journal, Economic Geology, has an excellent reputation and publishes papers relevant to all aspects of economic geology; c) membership is global and diverse, with almost 7,000 members in 106 countries (~60% industry, 40% academia and government); d) outreach to students and young professionals is at an all-time high, with 71 Student Chapters in 25 countries and more than $500,000 distributed in 2011 in support of student field trips and research and training (to 90 individual students from >50 universities in 13 countries); and e) the Societys education and training program has been strongly reenergized, with over 25 courses slated for 2013, including workshops, short courses, and field courses. Without a doubt, the strong commodity prices of the last several years have helped, but the good health of SEG is largely a testament to the outstanding work of our Littleton (Colorado) staff, as well as the generosity of the Societys volunteers and patrons with respect to time and financial support. I wish to highlight here a particular success storythe organization of the SEG 2012 Conference in Lima, Peru, last Octoberand the reasons for holding this meeting in Latin America. This was the third SEG conference held outside North America and the first major SEG conference organized in a non-Englishspeaking country. As those of you who attended this event can attest, SEG 2012 Lima had something for everyone: the participants (951 delegates from 36 countriesregistration had to close several weeks before the meeting) took part in a relevant technical program that had real depth, with high-quality presentations, keynote lectures, and posters; both the main conference and the field trips and short courses were sold out, demonstrating the interest from Peru, Latin America, and around the world. The SEG program was integrated with the local XVI Congreso Peruano de Geologa; the overall success was thanks to the leadership of the Peruvian and regional organizers and volunteers, among others. To celebrate this milestone, and in the spirit of SEG 2012 Lima, I am pleased and honored to write the first (and, for me, only) bilingual Presidential Column. How did we get here? In 1998, Peru surpassed Chile as the Latin American country with the largest number of SEG members. Within a few years of continued growth, Peru trailed only the USA, Canada, and Australia in total SEG membership. But this is not all. Regionally, over the past 25 years, SEG membership in Latin America has grown twentyfold (see graph), from about 4% of the total membership in 1986 to almost 20% today. This is remarkable, and results from factors both external and internal to the Society. The economic fundamentals provide the foundation; resource-rich Latin America is a powerhouse in global metal production. Chile is the largest copper producer in the world and the fifth producer of silver; Mexico is no. 1 in silver and no. 5 in lead; Brazil is no. 3 in iron ore and no. 5 in tin; Peru ranks no. 2 in copper and silver, no. 3 in tin and zinc, and no. 6 in gold. Exploration budgets for all metals in each of these countries are in excess of $200 to 300 million each year. This means jobsplentiful and typically well paying jobs that allow a particularly enthusiastic younger generation of South American geologists to invest in their careers and professional development by subscribing to a professional society like SEG, which offers clear value. Another likely connection between SEG and economic geologists from Latin America is the geographic, geologic, and historical/cultural backbone provided by the Cordillera, which stretches over the entire 7000 American continent. In my view, however, 6000 there are two are main factors that contributed to 5000 where we are today: the vision and deliberate actions of the leaders of the Society 4000 in the 1980s and 1990s, and the remarkable impact of a 3000 relatively small number of extraordinary volunteers 2000 and Society ambassadors in Latin America, starting in the 1990s. The former 1000 strengthened the foundation of SEG, focusing on 0 broadening the Society 1986 around the world; the fifteen SEG presidents since 1999 have been based in seven difANTONIO ARRIBAS R ferent countries, (SEG 1994 F) and only four SEG President 2012 were from the United States. The latter includes a list of key people (too long to include here) who, again and again, dedicated time and energy on behalf of the Society, driven by their desire to contribute to the betterment of the economic geology community. When looked at in detail, the growth of SEG membership and of the Societys professional impact in Latin Americamainly reflects the combined effort of these individuals, who worked tirelessly, organizing symposiums, short courses, and invited lectures, and sharing their passion for geology with potential members and eager young geologists. They are the strength behind SEG and the reason we are doing so well and will continue to do well as long as we continue to be relevant. We all owe a debt of gratitude to them and to the conference organizers for the success of the SEG 2012 Lima Conference, which caps over a decade of growth and impact. Going forward, the success story for SEG in South America raises hopes and expectations with respect to our ambitious goals for growth in Asia and Africa. It also raises questions as to sustainability and what we need to do to be prepared. 18 Latin American countries (right axis) Argentina Bolivia Brazil Chile Colombia Ecuador Mexico Peru Total SEG members combined (left axis)

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PRESIDENTIAL PERSPECTIVE

Solo una cuestin de tiempoPodemos decir con confianza que nuestra Sociedad lo est haciendo bien. Algunos de nuestros puntos fuertes son: a) una slida situacin financiera, gracias en buena parte a generosas y numerosas donaciones privadas, b) la revista Economic Geology disfruta de una reputacin excelente y publica artculos relevantes en todos los aspectos de la geologa econmica, c) la proyeccin global de la Sociedad es evidente, con una representacin de 106 pases entre sus 7000 miembros y un alto grado de diversificacin entre los socios (60% en la industria y 40% en el mbito acadmico/gobierno), d) el compromiso con los estudiantes de geologa y jvenes profesionales es el ms alto en la historia de la Sociedad, con 71 secciones de estudiantes en 25 pases y ms de medio milln de dlares distribuidos en 2011 en apoyo de viajes de campo y proyectos de investigacin de >90 estudiantes procedentes de >50 universidades en 13 pases, y e) el programa educativo y de formacin de la Sociedad ha sido intensamente revitalizado, y para el ao 2013 cuenta con ms de 25 cursos incluyendo talleres, viajes de campo y seminarios. Sin duda, el alto precio de los metales en los ltimos aos ha contribuido a conseguir estos logros. Aunque la buena salud de la Sociedad se debe principalmente al increble trabajo de los empleados de la oficina central de Littleton, Colorado, y a la generosidad de los voluntarios de todo el mundo. Quiero resaltar aqu un xito en particular: la organizacin en el mes de octubre pasado del congreso SEG 2012 en Lima, Per, y las razones para celebrar este encuentro en la Amrica Latina. SEG 2012 fue el tercer congreso de la Sociedad celebrado fuera de EE.UU. y la primera conferencia principal de la Sociedad organizada en un pas no anglfono. Como aquellos de ustedes que asistieron a este evento pueden confirmar, SEG 2012 Lima fue un enorme xito y ofreci algo de inters para todo el mundo. Los 951 asistentes procedentes de 36 pases (podran haber sido muchos ms, pero se tuvo que cerrar la inscripcin con mucha antelacin por falta de espacio), disfrutaron de un interesante programa tcnico con conferencias magistrales, presentaciones y posters de un gran nivel y con excursiones de campo y seminarios que despertaron un gran inters. Adems, la conferencia de la SEG se celebr conjuntamente con el XVI Congreso Peruano de Geologa, y en estrecha y fructfera cooperacin con la Sociedad Geolgica del Per. Nuevamente, el xito se debi al liderazgo y enorme capacidad de organizacin de unos incansables voluntarios. Para celebrar este hito y siguiendo el espritu de la conferencia SEG 2012, tengo el placer y el honor de escribir esta primera columna presidencial en ingls y en espaol. Esto ltimo era slo una cuestin de tiempo. Y cmo llegamos aqu? En 1998, Per super a Chile como el pas latinoamericano con el mayor nmero de miembros de la SEG. Despus de unos pocos aos de crecimiento contnuo, Per se convirti en el cuarto pas del mundo, detrs de EE.UU., Canad y Australia, en cuanto al nmero de miembros SEG. A nivel regional, en los ltimos 25 aos, el nmero de miembros de la Sociedad en la Amrica Latina se ha multiplicado por 20 (ver grfico), desde aproximadamente el 4% del total de afiliados en 1986 a casi el 20% en la actualidad. Esto es impresionante, y es el resultado de factores tanto externos como internos a la Sociedad. La base de este crecimiento obedece a razones econmicas fundamentales; su riqueza en recursos minerales convierte a Amrica Latina en una potencia mundial en la produccin de metales. Chile es el mayor productor de cobre del mundo y el quinto de plata, Mxico es no. 1 en plata y no. 5 en plomo; Brasil es no. 3 en mineral de hierro y 5 de estao, y el Per ocupa el lugar no. 2 en cobre y plata, no. 3 en estao y zinc, y 6 en oro. Los presupuestos anuales de exploracin en estos pases superan los 200 y 300 millones de dlares. Esto se traduce en abundantes y, por lo general, bien remunerados puestos de trabajo, que permiten a una generacin particularmente entusiasta de jvenes gelogos americanos invertir en su carrera y desarrollo profesional, hacindose miembros de una sociedad profesional como la SEG, que ofrece un valor claro e inmediato. Quizs otra razn para la conexin entre SEG y los gelogos de la Amrica Latina es la columna vertebral geogrfica, geolgica, cultural e histrica que representa la cordillera que se extiende de Norte a Sur por todo el continente americano. Sin embargo, creo que adems hay otras dos razones principales que nos han llevado a donde nos encontramos hoy: una es la visin y accin intencionada de los dirigentes de la Sociedad en las dcadas de 1980 y 1990; la otra es el enorme impacto en la Amrica Latina de un nmero relativamente pequeo de voluntarios y amigos de la Sociedad, especialmente a partir de la dcada de 1990. Los lderes de la Sociedad de hace 20 a 30 aos fortalecieron para siempre la SEG al dar prioridad a la proyeccin internacional. As, entre los quince presidentes de la SEG desde 1999 nos encontramos con siete pases diferentes de residencia profesional. En cuanto a los voluntarios y amigos de la Sociedad que tanto impacto han tenido en cuanto a la influencia de la misma en la Amrica Latina, stos integran una lista demasiado larga para incluirla aqu. Ellas y ellos han dedicado generosamente su tiempo y energa, impulsados por un sincero deseo de contribuir a la mejora del desempeo de la geologa econmica en la regin. De hecho, un anlisis detallado del crecimiento de la SEG en la regin pone en evidencia la huella de estas personas en eventos particulares como la organizacin de un simposio especfico, la presentacin de un curso o de una conferencia invitada determinada, la conversacin individual con un joven gelogo, etc. Ellos/as son realmente la gran fuerza detrs de la SEG y la razn de los xitos que estamos ahora celebrando y que celebraremos con seguridad en el futuro, siempre que continuemos ofreciendo calidad. Con ellos, as como con los organizadores de SEG 2012 Lima, tenemos todos una deuda de gratitud por este xito, que culmina ms de una dcada de crecimiento e impacto. Mirando hacia el futuro, los xitos en Latinoamrica son un estmulo para la Sociedad en sus ambiciosas metas en Asia y Africa. Al mismo tiempo, deben hacernos reflexionar sobre la sustentabilidad de este crecimiento y sobre que necesitamos hacer para estar preparados. 1

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No 92 JANUARY 2013

F O U N D AT I O N P R E S I D E N T I A L P E R S P E C T I V E

The SEGF Field Course Program: A Continuing EndeavorThe late Professor Charles Meyer of the University of California at Berkeley used the term students to describe all of us in geology, with emphasis on those of us involved with economic geology, in which he had a noteworthy career. The SEG Foundation has an essential mission to support and offer a variety of educational programs, directed precisely at the students about whom Professor Meyer spoke. The continuing task of offering polished, high-quality courses is dependent on the time and efforts of many SEG volunteers, and on the financial support of SEG members and the companies they represent. Especially notable among the activities supported by the Foundation are the student-dedicated field courses (not field trips), which emphasize the practical aspect of economic geology by providing students (yes, this means both academic and professional students) with opportunities to visit mining districts and exploration properties, and to discuss their career interests with mine and exploration geologists, mine engineers, metallurgists, and mine management. These courses are limited to 20 participants (see article on the recent Southern Per Porphyry Systems Field Course in this issue) and offer course leaders and mine personnel the chance to share experiences and expectations and, in doing so, to add substantively to the out-of-classroom knowledge of the participants. The direct enhancement of learning about career paths in economic geology cannot be overstated, as indicated by the student-provided reviews of these courses. The Foundations Field Course Program, headed by Borden Putnam, typically offers two field courses each year, with the substantial expense of doing so borne largely by SEG member and corporate contributions. As these courses are offered on an international basis, student participants represent a wide variety of cultural and academic backgrounds; expenses for these students are almost entirely covered by the Foundation, making a valuable educational opportunity available to future economic geologists. Given the significance of these field courses, ten of which have been WILLIAM X. CHVEZ, JR. offered since the SEG Foundation President 2013 inception of the program in 2007, it is critically important to ask for your continued support. It is very likely that each of us benefited from the encouragement of an exploration or mining geologist who, somewhere along the line, took an interest in our development as budding young professionals. As part of this encouragement, I ask each of you to consider making an especially generous donation to the SEGF Field Course Fund in order to allow the Foundation to continue providing opportunities to engaged young geologists. Your support will allow the organizers and leaders of these field courses, who volunteer their time and energy, to continue to focus on the instruction of the next generation of exploration geologists. 1

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SEG Contributions 9/1/201211/30/2012SEG General Fund$

3,000 1,000

Reid, William, USA$

Patton, Thomas, USA$

300$500

Arce, Jose, Peru Arribas R, Antonio, Singapore Bout, Jean-Paul, Australia Hernandez Pinto, Edmundo, Chile Pincus, William, USA Swarthout, Andrew, USA$

100$250

Albinson, Tawn, Mexico Andrew, Colin, Ireland Avalon Development Corp., USA Barnes, Hubert, USA Benavides Alfaro, Jorge, Peru Cadwell, David, USA Cajachagua Zevallos, Victor, Peru Dail, Christopher, USA Everett, Jack, USA Fournier, Robert, USA Hamm, Jack, USA Henry, Christopher, USA Hodkiewicz, Paul, Australia Hudak, George, USA Jara Montenegro, Jose, Chile Kakarieka, Alejandro, Chile Kotlyar, Boris, USA Kuhn, Paul, Portugal Longo, Anthony, USA McCurdy, Karr, USA McDonald, Bruce, Malaysia McIntosh, Stephen, Australia Mupande, Jean Flix, Congo Parry, John, USA Pinsent, Robert, Canada Quijano Laime, Freddy, Ecuador Struhsacker, Eric, USA Woodman, John, USA

Up to 99Adamides, Nicos, Cyprus Anzman, Joseph, USA Barnard, Fred, USA Beale, Timothy, Canada Bettles, Keith, USA Boutes, Georges, France Boyes, Matthew, United Kingdom Castillo, Boris, Chile Clifford, John, Ireland Cook, Douglas, New Zealand Crdova, Julio, Peru Cortes, Marcelo, Chile Craig, Lindsay, USA Davis, Mark, United Kingdom de Carvalho, Delfim, Portugal Della Libera, Michele, Italy Durning, William, USA Easdon, Michael, Chile

$

El-Raghy, Sami, Australia Garay, Enrique, Peru Garcia, Octavio, Australia Gillerman, Virginia, USA Hawley, Charles, USA Irwin, Raymond, USA Johnson, Ajeet, USA Jongewaard, Peter, USA Kay, Suzanne, USA Kekana, Sello, South Africa Kershaw, Byard, USA Klau, Wolfgang, Germany Lambert, Andre, Belgium Lienhard, Walter, USA Logsdon, Mark, USA Lorge, David, USA Ludington, Stephen, USA McEwan, Craig, Australia McGregor-Dawson, James, Australia McKelvey, Gregory, USA More, Syver, USA Murakami, Hiroyasu, Japan Naldrett, Anthony, United Kingdom Neathery, Thornton, USA Odan, Yoshiaki, Brazil Ogata, Takeyuki, Japan Ortiz Ramos, Giovanny, Colombia Pereira, Elton, Brazil Polozov, Alexander, Russia Portacio, Jose, USA Potts, Stephen, Canada Ramos, Frank, USA Reidel, Stephen, USA Rodriguez Pevida, Luis, Spain Ruppel, Edward, USA Scott, Elizabeth, USA Sharp, W. Edwin, USA Shimizu, Toru, Japan Silva, Pedro, Chile Sims, Samuel, USA Spivey, Martin, Australia van Maastrigt, Peter, Greenland Whiteford, Sean, USA Wire, Jeremy, USA Yambrick, Robert, USA Zohar, Pamela, USA

$

100$150

Hugo Dummett Fund$

Babcock, Russell, USA Begg, Graham, Australia Brown, Stephen, Chile Eggers, Alan, Australia Foster, Robert, United Kingdom Glavinovich, Paul, USA Graybeal, Frederick, USA Hammer, Donald, USA Hardy, David, USA Hodkiewicz, Paul, Australia Janecky, David, USA Jenkin, Gawen, United Kingdom Jennings, Donald, USA Juhas, Allan, USA Laidlaw, Robert, USA Lorson, Richard, USA Manske, Scott, USA Margeson, G. Bradford, USA Marlowe, Karl, USA Metzenheim, Brian, USA Pinsent, Robert, Canada Struhsacker, Eric, USA Wallace, Alan, USA

500

Drobeck, Peter, USA Okita, Patrick, USA$

200$250

Broughton, David, South Africa Cocker, Mark, USA Petersen, Mark, USA Zuker, J. Stevens, USA$

100

Bolton, Barrie, Australia Cappa, James, USA Diallo, Madani, France Hoye, Jonathon, Australia Mathewson, David, USA Price, Barry, Canada Schafer, Robert, USA Thompson, Tommy, USA Tyrwhitt, David, Australia

Up to $99Bahia-Guimaraes, Paulo, Brazil Boronowski, Alex, Canada Craig, Lindsay, USA Hatfield, Richard, Australia Lenzi, Gary, USA Logsdon, Mark, USA McLean, Neil, Australia More, Syver, USA Parker, Harry, USA Scott, Michael, South Africa Walsham, Bruce, United Kingdom Wurst, Andrew, USA

Up to $99Loring, Richard, USA Beale, Timothy, Canada Craig, Lindsay, USA Della Libera, Michele, Italy Durning, William, USA Gostevskikh, Alex, Canada Hauck, Steven, USA Irwin, Raymond, USA Lienhard, Walter, USA Metz, Robert, USA More, Syver, USA Noronha, Fernando, Portugal Rogers, Kenneth, Australia

Hickok-Radford Fund$

100$200

The Discovery Fund$

5,000 1,200

Parratt, Ronald, USA$

Freeman, Curtis, USA Miller, Lance, USA Millholland, Madelyn, USA Petersen, Mark, USA Puchner, Christopher, USA Turner, Thomas, USA

Loudon, A. Geoff, New Zealand$

Up to $99Spurney, John, USA Bernstein, Stefan, Denmark Craig, Lindsay, USA Hawley, Charles, USA Hoye, Jonathon, Australia Leonard, Kevin, USA Leveille, Richard, USA Lindberg, Paul, USA

SEG Foundation General Fund$

100$200

3,000

Reid, William, USA$

500$750

Benavides Alfaro, Jorge, Peru Christensen, Odin, USA Paul, E. Kenneth, USA Steininger, Roger, USA$

Gorzynski, George, Canada Hatton, Owen, Chile Hoye, Jonathon, Australia Kerr, Jim, Australia Maryono, Adi, Australia Mathewson, David, USA Thomsen, Michael, USA

Up to $99Almasan, Radu, Chile Coppard, James, United Kingdom Craig, Lindsay, USA de Carvalho, Delfim, Portugal Mcnulty, Kevin, Ireland Randall, Scott, New Zealand Salado Paz, Natalia, Argentina Schafer, Robert, USA

McKinstry Fund$

200$375

1,000

Cardozo, Miguel, Peru Cluer, J. Kelly, USA May, David, USA Muessig, Siegfried, USA Powers, Sandra, USA

Hardesty, Ian, USA$

100$250

Broughton, David, South Africa Einaudi, Marco, USA Greybeck, James, USA

JANUARY 2013 No 92

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Thank you for your generous contributions to the Society and the SEG Foundation.Gustafson, Lewis, USA Jones, Richard, USA MacIntyre, Timothy, USA Petersen, Mark, USA Hitzman, Murray, USA Hunt, John Paul, South Africa Ihlen, Peter, Norway Jara, Constanza, Chile Kirmasov, Alexey, Russia Lorson, Richard, USA MacTavish, Allan, Canada Marinov, Daniel, Canada Maynard, Stephen, USA McCusker, Robert, USA McEwan, Craig, Australia McNamara, Galen, Canada Nettle, John, Australia Petersen, Mark, USA Puchlik, Kenneth, USA Shaw, Eleanor, United Kingdom Thompson, Tommy, USA Venable, Margaret, USA

Up to $99Bahia-Guimaraes, Paulo, Brazil Barnard, Fred, USA Craig, Lindsay, USA Custodio Pazos, Shirley, Peru

$

200$275

Up to $99Alvarez, Nestor, Argentina Astorga Delgadillo, Carlos, Peru Craig, Lindsay, USA Feinstein, Michael, USA Garcia, Walter, Peru Gearity, Evan, USA Glass, Frank, Canada More, Syver, USA Oyarzun, Jorge, Chile Phillips, Allison, USA

Student Fellowship Fund SEG Foundation Corporate Sponsors$

Alldrick, Dani, Canada Britten, Ronald, Canada Broughton, David, South Africa Carlson, Gerald, Canada Galley, Alan, Canada MacTavish, Allan, Canada McDonald, Dean, Canada Olson, Reginald, Canada Stockford, Howard, Canada$

100$150

50,000

The Timothy Nutt Memorial Fund$

Anglo American plc, United Kingdom Anglogold Ashanti Australia, Australia$

300

Up to $99Gearity, Evan, USA Ashley, Paul, Australia Barnard, Fred, USA Bettles, Keith, USA Boullier, Anne-Marie, France Brodie, Colin, Argentina Craig, Lindsay, USA Daroch, Giancarlo, Chile Davis, James, USA Dykeman, Candace, USA Herbort, Thomas, Switzerland James, Ronald, New Zealand Jennings, Keenan, United Kingdom Johnson, David, USA Jones, Philip, Australia Kell, Robert, USA Kleinkopf, M. Dean, USA Krol, Leendert, USA Lenzi, Gary, USA Lindberg, Paul, USA Litaay, Naomi, Indonesia Martins, Breno, Brazil Mathewson, David, USA McKelvey, GRegory, USA Mudry, M. Phillip, Canada Mueller, Andreas, Australia Polozov, Alexander, Russia Riedell, K. Brock, Canada Schloderer, John, USA Simpson, Thomas, USA Taguchi, Sachihiro, Japan Wallis, Toni, Canada Weiss, Steven, USA Wright, Timothy, Switzerland

30,000

Thomson, Brian, Brazil$

Barrick Gold Corporation, Canada

100$120

Barnard, Fred, USA Chadwick, Peter, Canada Foster, Robert, United Kingdom Graham, Nick, Zimbabwe Jones, Paul, USA Schafer, Robert, USA

1$

$1,000Seavoy, Ronald, USA

Up to $99Craig, Lindsay, USA Deane, John, South Africa Hlabangana, Sitshengiso, Zimbabwe Misiewicz, Julian, United Kingdom Nowak, Gregory, USA Oberthuer, Thomas, Germany Olson, Steven, USA Phillips, Geoffrey, Australia Scott, Michael, South Africa Thamm, Albert, Australia Venter, Mike, South Africa

100

Dail, Christopher, USA Kotlyar, Boris, USA Mauk, Jeffrey, USA

Up to $99Barnard, Fred, USA Bentley, Andrew Bjerg, Ernesto, Argentina Boily, Michel, Canada Bookstrom, Arthur, USA Craig, Lindsay, USA Deiparine, Leo, Philippines Gillerman, Virginia, USA Johnson, David, USA Kell, Robert, USA Leybourne, Matthew, Canada Litaay, Naomi, Indonesia Orozco Quintana, R. Dagoberto, Mexico Phillips, Allison, USA Polozov, Alexander, Russia Riedell, K. Brock, Canada Wright, Timothy, Switzerland

Brisbin, Daniel, Canada Chadwick, Peter, Canada Chantal, Jolette, Canada Devine, Fionnuala, Canada DIon, Claude, Canada Fonseca, Anna, Canada Gagnier, Claude, Canada Gonzalez, Ralph, USA Gorzynski, George, Canada Hannington, Mark, Canada Hocking, Michael, Canada Liverton, Timothy, Canada Malfair, Mark, Canada Nordin, Gary, Canada Pawliuk, David, Canada Perreault, Serge, Canada Price, Barry, Canada Sauve, Pierre, Canada Stott, Greg, Canada Tosdal, Richard, USA Watkins, John, Canada Willoughby, Neil, Canada

Up to $99Bailey, David, Canada Bird, Howard, Canada Blanchflower, John, Canada Boronowski, Alex, Canada Bridge, David, Canada Burrows, David, Canada Cashin, Peter, Canada Channer, Dominic, Ecuador Craig, Lindsay Della Libera, Michele, Italy Gostevskikh, Alex, Canada Grace, Kenneth, Canada Griffith, Twila, Canada Guay, Mathieu, Canada Hollings, Peter, Canada Mudry, M. Phillip, Canada Mumin, A. Hamid, Canada Prosh, Eric, Canada Rees, Matthew, Canada Richards, Jeremy, Canada Scoates, Jon, Canada Sebert, Christopher, Canada Smith, Scott, Chile Southam, Philip, Canada Whiteford, Sean, USA Williams, Steven, Canada

Student Field Trip Fund$

15,000 1,000

Anonymous, USA$

Seavoy, Ronald, USA$

100$250

Backer, Harold, USA Blakestad, Robert, USA Broughton, David, South Africa Brozdowski, Robert, Canada Buhov, Valentin, Bulgaria Burrows, David, Canada Burstow, William, USA Chamberlain, Corrie, Argentina Dail, Christopher, USA Fonseca, Anna, Canada Gorzynski, George, Canada Graf, Joseph, USA Hantler, Aaron, Australia

The Alberto Terrones L. Fund$

Canada Foundation$

1,000$

200 100

Franklin, James, Canada

Petersen, Mark, USA$

500

Enriquez, Erme, Mexico Figueroa, Francisco, Mexico Gorzynski, George, Canada

Davidson, Alex, Canada Hodder, Robert, Canada Linnen, Robert, Canada Robert, Franois, Canada

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Rediscovering the Discovery Outcrop: The Promises and Pitfalls of LiDAR Technology in Mineral Exploration (Continued)

exploration efforts to unexplored frontiers in low latitudes. In the late 20th and early 21st centuries, two factors shifted much exploration emphasis to tropical and boreal forest terrains. The first was favorable political and economic liberalization and a drift away from state-directed enterprises in Asia, Africa, and South America (e.g., Tilton et al., 1988). Furthermore, the boreal terrains of Canada, Alaska, and Europe became appealing for exploration as existing mineral districts of these countries were developed or came under more stringent environmental oversight. Although ground and airborne geophysics will continue to be a premier tool for exploration in heavily vegetated terrains, knowledge of surface geology as well as knowing where rock outcrops might be or whether they even exist in these areas will be critical for successful exploration efforts. To that end, the relatively new technology of Light Detection and Ranging (LiDAR), with its ability to produce cm-scale terrain elevation data, is in the process of becoming an important remote sensing tool in mineral exploration. The underlying premise of using LiDAR in mineral exploration is that specific rock types and their associated alteration produce recognizable topographic patterns that are resolvable with standard LiDAR techniques. For instance, the silicification associated with a variety of porphyry and vein deposits is more resistant to weathering than surrounding country rock (Lovering, 1972; Hedenquist et al., 2000), producing a modest topographic high discernable with standard geographic information system (GIS) software. Likewise, argillic alteration with clays that weather easily could produce a recessive topographic signature.

LIDAR BACKGROUND AND APPLICATIONSAs computing power has grown, digital elevation models (DEMs) have progressively increased in resolution, availability, and utility and gradually become a formidable tool for unraveling a variety of features on the surface of the Earth. Early DEMs relied on digitizing existing topographic maps or applying photogrammetric techniques to stereo aerial photography. Subsequently, radar became a source for computing the distance

from satellite or airborne platforms to the Earths surface. However, neither photogrammetric nor radar methodologies effectively penetrate extensive vegetative cover and thus are of limited use for resolving very fine scale features at the Earths surface that are typically of interest to economic geologists, who rely on the subtle topographic expression of ore deposit features in their work. In recent years LiDAR has been effectively applied to earth science as well as fields as diverse as art history and transportation engineering. Using a laser source, LiDAR is capable of producing remarkably fine-scale topographic maps and three-dimensional images and can detect subtle surface features on a wide variety of scales. The method relies on sending and receiving coherent laser pulses (current technology at the rate of ~105 Hz) to the object being surveyed. LiDAR instruments can be mounted on airborne or ground-based (terrestrial) platforms. Careful and sophisticated data acquisition and postprocessing are necessary to achieve reliable and reproducible data. Airborne LiDAR relies on kinematic aircraft global positioning systems (GPS) and static ground GPS to correctly georeference the data obtained from a moving aircraft high above the ground. Flight lines are flown such that coverage overlaps between the lines. All LiDAR instruments produce point cloudsindividual x-y-z coordinates that may possess additional attributes such as relative intensity. A variety of methods transform the irregularly spaced point cloud into the evenly spaced raster files necessary for modern rapid computer analysis. The resulting spatial resolution is a function of the number of returns per area: for airborne LiDAR, postprocessed horizontal postings are generally 1 to 2 m whereas vertical resolution is on the order of a few centimeters. Individual airborne LiDAR pulses are generally recorded as a series of returns of varying intensity from different surfaces (e.g., foliage, rocks, bare ground) encountered by an individual pulse. The first return is useful for tasks such as documenting forest canopy heights in biological surveys. However, geologists are most interested in the ground surface, where geologic features become manifest. One of the crowning achievements of LiDAR technology is its ability to see through vegetation and forest canopies based on the last return of the

laser pulses. In effect, postprocessing of LiDAR data filters out returns from tree and vegetative cover to reveal important features of the underlying land surface. LiDAR surveys are gradually being incorporated into the mapping and documenting of a variety of geologic features. Unknown or poorly characterized fault scarps and landslides have been discovered and mapped in heavily vegetated areas such as Puget Sound (e.g., Haaugerud et al., 2003). LiDAR is gradually being incorporated into fundamental activities such as bedrock geologic mapping, principally in identifying linear geologic structures (e.g., Pavlis and Bruhn, 2011) or revising and expanding mapping efforts in heavily vegetated terrains (e.g., Grebby et al., 2010; Tabor et al., 2011). Applications combining LiDAR with hyperspectral investigations of geothermal areas (Silver et al., 2011) have also appeared.

APPLICATION TO MINERALIZED AREASExamples from three historic mining districts in Utah and Oregon (Fig. 1) show the possibilities and possible pitfalls of using LiDAR to understand manifestations of hydrothermal alteration and mineralization. The three settings represent a variety of geologic features, vegetation cover, and LiDAR data quality (Table 1). The areas were chosen on the basis of easy field access and LiDAR data that were publically available for little or no cost. While none are in frontier exploration areas of boreal or tropical forests, the surface geologic manifestations can provide a context for looking at similar features in such terrains.

Alta district, UtahThe Alta (also known as the Little Cottonwood-American Fork) and Park City mining districts in north-central Utah were active starting in the 1860s and productive until the 1950s (Boutwell, 1912; Calkins and Butler, 1943). The area examined in detail is in Thaynes Canyon, northeast of Alta and immediately west of the Park City mining district (Fig. 2). The eastward-trending drainage is steep and heavily forested on the N-facing slopes. The little outcrop that exists in the valley is typically cloaked by vegetation or glacial till whereas the rocks on the ridges are relatively well exposed. The geology of the

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TABLE 1. Characteristics of Mining Districts and LiDAR Data Sets Employed in This Study Alta, Utah Host rocks Mesozoic sedimentary rocks; Tertiary intrusions Mineralized fissures, skarns Jupiter mine (Ag, base metals) Patchy conifer forest State of Utah Automated Geographic Reference Center 2-m horizontal Frisco, Utah Lower Paleozoic carbonates; Tertiary intrusions Mineralized fissures, skarns Unnamed prospect near Indian Queen mine (base metals) Sparse juniper and sagebrush U.S. Department of Agriculture, Salt Lake City Office 2-m horizontal North Santiam, Oregon Tertiary volcanic rocks; minor intrusions Mineralized veins Blue Jay mine (Au, base metals) Dense conifer forest Oregon LiDAR Consortium; opentopography.org 1-m horizontal

Alteration style Ore deposit/ prospect name Vegetation cover LiDAR availability

LiDAR resolution

canyon consists of the Woodside Shale, a fine-grained dark red shale; the Thaynes Formation, a limy sandstone; and the Ankarah Formation, composed of sandstone, mudstone, and shale (all of Triassic age). The contact aureole is associated with the Clayton Peak stock, a mid-Tertiary quartz monzodiorite (Bromfield, 1989) intruded by a series of intermediate dikes that trend northeastsouthwest. The Jupiter mine at the bottom of Thaynes Canyon produced silver and base metals from NE-trending fissures (Boutwell, 1912).

LiDAR shows a landslide feature not visible in aerial photography or documented on the geologic map of the area (Fig. 2). The valley area was glaciated in the Quaternary and is still largely covered by glacial deposits. Several lateral moraines appear to align with the intermediate dikes mapped by Baker et al. (1966) on the LiDAR image (Fig. 3). Field examination by the authors did not establish a definitive northeast outcrop trend of the intermediate dikes in the field, although there is a suggestion of such a feature in the LiDAR (Fig. 3). Neither the moraines nor the dikes are apparent in the aerial photograph (Fig. 3A). On the ridge north of the canyon, the Thaynes Formation and Woodside Shale are clearly offset by NNE-trending faults visible in both the aerial photo and LiDAR hillshade (Fig. 4). The bedding plane visible in the LiDAR provides an opportunity to compare bedding orientations collected in the field with those derived with the freeware MICRODEM program (available through the U.S. Naval Academy, http://www.usna.edu/ Users/oceano/pguth/website/microdem/ microdem.htm). Three points picked by MICRODEM produce an orientation (N64W, 35NE) that compared favorably with orientations collected by the authors (N60W, 30NE) as well as those shown on the geologic map of Baker et al. (1966).

FIGURE 3. A. NAIP digital photograph of the Shadow Lake area shown in Figure 2. B. Detailed hillshade of the cirque area with overlain geologic units. C. Details of the features in the Shadow Lake cirque area. Qm = Quaternary moraine material.

Frisco district, UtahThe Frisco mining district is located in the San Francisco Mountains, ~40 km west of Milford, Utah (Fig. 1). Although the Horn silver mine in the eastern portion of the district was a large producer of silver and base metals in the late 19th and early 20th centuries (Butler, 1913), very little modern geologic research has been conducted on the district. The area examined in detail is immediately south of the Indian Queen mine on the west flank of the San Francisco Mountains. The main workings are in skarn of the Cambrian Big Horse Limestone where it was intruded by the Oligocene Cactus stock (Hintze, 1984). Limestone to the north of the contact has been extensively altered, recrystallized, and is locally ferruginous (Fig. 5). The area is covered by a very sparse juniper forest, thus permitting a comparison between features seen in the field, on aerial photography, and with to page 16 . . . LiDAR-derived DEMs.

FIGURE 2. A. Geologic map of a portion of Brighton quadrangle in the Alta mining district of Utah (Baker et al., 1966). Boxes show areas of Figures 3 and 4. B. Hillshade of LiDAR-derived DEMs of the area in A. C. National Agricultural Imagery Program (NAIP) photograph of the area in A and B. Abbreviations: ap = porphyry of the Clayton Peak stock (Tertiary), cp = granodiorite of the Clayton Peak stock (Tertiary), ind = intermediate dikes (Tertiary), Qm = Quaternary moraine material, Trt = Thaynes Formation (Triassic), Trw = Woodside Formation (Triassic).

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Rediscovering the Discovery Outcrop: The Promises and Pitfalls of LiDAR Technology in Mineral Exploration (Continued)

In spite of the problems with the LiDAR data in this area, the utility of this technique is illustrated by a close examination of rocks north of the main Indian Queen workings. A rusty, WNWtrending zone of silicified limestone (jasperoid) is readily apparent in the field as well as the LiDAR hillshade, yet is virtually invisible on the aerial photo (Fig. 7). Were this mineralized feature located in an area of dense vegetation, the LiDAR data would have been very useful in pinpointing an area for the exploration geologist to investigate and sample.

North Santiam district, OregonThe North Santiam district is located in the central Cascade Mountains of Oregon (Fig. 1), an area dominated by Cenozoic volcanic rocks of variable but generally intermediate composition (Peck et al., 1964). Our study focused on two areas of prospects and underground workings (Ruth and Blue Jay mines) near the headwaters of the Little North Santiam River (Callaghan and Buddington, 1938) (Table 1). The North Santiam area is characterized by extremely rugged topography with dense conifer forest and ground cover vegetation (Fig. 8A). In this setting, considerable information regarding the pros and cons of LiDAR

FIGURE 4. A. NAIP digital photograph of the ridge in the northern portion of Figure 2. B. Detailed hillshade of the ridge area with geology from Baker et al. (1966). C. Digital points (squares) used to produce a strike and dip of the Thaynes Formation on the ridge line. Abbreviations: ind = intermediate dikes (Tertiary), Trt = Thaynes Formation (Triassic), Trw = Woodside Formation (Triassic).

FIGURE 6. A. Hillshade of LiDAR DEMs of the Indian Queen mine area. B. Detail of Frisco (same area as A) showing misaligned LiDAR swaths. C. Cross section of DEM data from along line a-a.

LiDAR data encompassing the Indian Queen mine are part of a larger survey conducted by the U.S. Department of Agriculture to study the hydrology of the Wah Wah Valley to the west (Meier, 2005). Problems associated with LiDAR coverage in this area are clearly apparent in GIS-produced hillshades of the area (Fig. 5). Obvious horizontal lineaments appear to be present where two flight lines of the survey overlapped (Fig. 6). The stair-stepped topographic profile of the area (Fig. 6C) is suggestive of an offset in georeferencing between two flight lines, although a postprocessing error in the data cannot be discounted. These and a variety of other problems in the survey are noted by Meier (2005), although specific remedies are not suggested.FIGURE 5. A. Hillshade of LiDAR-derived DEMs of the area near the Indian Queen mine, Frisco mining district, Utah. Squares show areas of Figures 6 and 7. B. Generalized geologic map of the Indian Queen mine area (Jewell, unpub. data).

can be gathered. The detail seen in the DEMs is directly related to the density of laser shots (Fig. 8B-D). Where shot density is sparse, gaps in the DEMs, manifested as irregularly sized triangular facets, emerge from postprocessing due to the paucity of last returns (Fig. 8D). While access roads to the mined area and drainages are vaguely discernable on aerial photographs (Fig. 8, 9), LiDAR hillshades show very distinctly the location of outcrops and adits (Fig. 9B).

DISCUSSIONThe examples shown here illustrate the importance of high-quality data acquisition and postprocessing for producing accurate and usable LiDAR. To this end, vigorous QA/QC procedures must be followed after LiDAR is flown, as the survey of the Frisco district clearly shows. LiDAR data from heavily vegetated or forested terrain should be compared to high-resolution GPS measurements, and very crude and possibly inaccurate DEMs can be expected where last return data are sparse (Fig. 8). Once high-quality LiDAR data are obtained, standard GIS software can reveal

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packages are summarized on websites such as OpenTopography.org.

Geologic considerationsThe results presented here were part of more extensive field investigations carried out by the authors and other University of Utah students in Utah and Oregon. In many cases, the hydrothermal alteration features associated with mineralized areas were not visible with LiDAR-derived DEMs. For instance, the accreted Mesozoic greenstone-volcanic terrain of the Blue Mountains of northeastern Oregon contains numerous historic vein gold deposits (Allen, 1951) and, although linear features were clearly visible in the LiDAR-derived DEMs, none could be definitively related to observed mineralized structures on the ground. Similar difficulties were encountered in the western and southern portions of the Alta district, where complex thrust and normal faulting are pervasive. However, as the three case studies presented above illustrate, LiDAR technology can be useful in areas where the geology is favorable. The technique appears most helpful where recessive linear features (e.g., fault in Thaynes Formation) (Fig. 4) or resistant features in an otherwise uniform geologic landscape (e.g., jasperoids in massive limestone) (Fig. 7) are present. Outcrop identification is another area where LiDAR can play an important role in mineral exploration. The radius of visibility on the ground in places such as the Cascades of Oregon is sometimes no more than a few meters, and knowing of the existence of outcrops, even where covered by moss (e.g., Fig. 9B), can be useful to the explorationist.

FIGURE 7. A. NAIP photograph of area immediately north of the Indian Queen mine. B. Hillshade of LiDAR-derived DEMs of the area in A. C. Field photography of WNW-trending silicified zone (jasperoid) in limestone.

many interesting geologic features. However, new software capable of enhancing geologic interpretations is continually appearing in this dynamic field. For instance, Pavlis and Bruhn (2011) mention half a dozen software packages they employed in their work and other software

technique to more traditional airborne geophysical methods. A large expense of any airborne geophysical survey is operation of the airborne platform (be it fixed wing or helicopter). Thus, the current expense of airborne LiDAR surveys (estimated to be $200$500/km2) could be pared down considerably were the equipment mounted in the same aircraft as other geophysical instruments. Unfortunately, considerable differences exist in the standard routines for collecting both forms of data, principally in the flight heights of the airborne platforms. Airborne geophysical surveys are typically conducted at relatively low elevations (100s of m) whereas airborne LiDAR surveys are acquired at much higher elevations (1,000s of m). However, LiDAR has the advantage that data can be collected at any distance; terrestrial surveys are typically done at ranges of 10 to 100 m. Because the horizontal spacing of the LiDAR data decreases with distance to the target, low-flying aircraft LiDAR could conceivably collect closely spaced (10s cm) data in conjunction with traditional geophysical instrumentation, thus providing the exploration geologist with extremely detailed images of the Earths surface. Some geophysical companies are now providing exactly these services (C. Barnett, pers. comm.).

CONCLUSIONSThe digital revolution in imaging surface geology has been brought about by the confluence of exponentially increasing computer power and the technological advances of remote sensing instruments. Exploration geologists, like all scientists, should become familiar with these new, rapidly advancing technologies and stand ready to incorporate them into their craft. In order for the world to provide the raw materials for expanding economies, new mineral deposits must be located (1) at greater depths in mature mining districts or (2) in areas that are prospective but have not received as much attention as the traditional mining provinces, such as those of the western United States. Examples of this latter category include the Precambrian shield of the Canadian Shield and upper Midwest of the United States (for instance, the Eagle Ni-Cu deposit, recently brought into production in the upper peninsula of Michigan) (Ripley and Li, to page 18 . . . 2011) and the majority

Piggybacking with other geophysical techniquesIt is envisioned that LiDAR could eventually become a complementaryFIGURE 8. A. NAIP photograph of area near the Blue Jay mine, North Santiam mining district, Cascade Mountains, Oregon. B. LiDAR shot density of the area in A. Blue squares represent fourth returns and small red squares represent third returns, showing the high degree of irregularity of last returns in areas of dense vegetation. C. Hillshade detail of LiDAR DEMs showing triangular facets produced in areas of low last return density. D. Close-up of area in B and C showing pits and triangular facets produced by postprocessing due to a paucity of laser shot returns.

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Rediscovering the Discovery Outcrop: The Promises and Pitfalls of LiDAR Technology in Mineral Exploration (Continued) Grebby, S., Cunningham, D., Naden, J., and Tansey, K., 2010, Lithologic mapping of the Troodos ophiolite, Cyprus, using airborne LiDAR topographic data: Remote Sensing of Environment, v. 114, p. 713724. Haaugerud, R.A., Harding, D.J., Johnson, S.Y., Harless, J.L., Weaver, C.S., and Sherrod, B.L., 2003, High resolution Lidar topography of Puget Sound lowland, Washington A bonanza for earth science: GSA Today, v. 13, p. 410. Hedenquist, J.W., Arribas R., A., and Gonzalez-Urien, E., 2000, Exploration for epithermal gold deposits: Reviews in Economic Geology, v. 13, p. 245277. Hintze, L.F., 1984, Geologic map of the Frisco Peak quadrangle, Millard and Beaver Counties, Utah: U.S. Geological Survey Misc. Investigations Map I-1573. Lovering, T.S., 1972, Jasperoid in the United Statesits characteristics, origin, and economic significance: U.S. Geological Survey Professional Paper 710, 164 p. Meier, C., 2005, Quality assurance review of LiDAR data for the Wah-Wah Valley, Beaver County, Utah: Cedar City, Utah, National Resource Conservation Service, 9 p. National Research Council, 2007, Elevation data for floodplain mapping: Washington, D.C. National Academies Press, 168 p. Pavlis, T.L., and Bruhn, R.L., 2011, Application of LIDAR to resolving bedrock structure in areas of poor exposure: An example from the STEEP study area, southern Alaska: Geological Society of America Bulletin, v. 123, p. 206217. Peck, D.L., Grigges, A.B., Schlicker, A.G., Wells, F.G., and Dole, H.M., 1964, Geology of the central and northern parts of the western Cascade Range in Oregon: U.S. Geological Survey Professional Paper 449, 56 p. Ripley, E.M., and Li, C., 2011, A review of conduit-related Ni-Cu-(PGE) sulfide mineralization at the Voiseys Bay deposit, Labrador, and the Eagle deposit, northern Michigan: Reviews in Economic Geology, v. 17, p. 181197. Silver, E., MacKnight, R., Male, E., Pickles, W., Cocks, P., and Wailbel, A., 2011, LiDAR and hyperspectral analysis of mineral alteration and faulting on the west side of the Humboldt Range, Nevada: Geosphere, v. 7, p. 13571368. Tabor, R.W., Haugerud, R.A., Haeussler, P.J., and Clark, K.P., 2011, LiDAR-revised geologic map of the Wildcate Lake 7.5 quadrangle, Kitsap and Mason Counties, Washington: U.S. Geological Survey Scientific Investigations Map 3187. Tilton, J.E., Eggert, R.G., and Landsberg, H.H., eds., 1988, World mineral exploration: Trends and economic issues: Washington, D.C., Resources for the Future, Inc., 464 p. Williams, C.L., Thompson, T.B., Powell, J.L., and Dunbar, W.W., 2000, Gold-bearing breccias of the Rain mine, Carlin trend, Nevada: Economic Geology, v. 95, p. 391 404. 1

FIGURE 9. A. NAIP photograph of area near the Blue Jay mine, North Santiam mining district, Cascade Mountains, Oregon. B. Hillshade of LiDAR-derived DEMs showing location of outcrops and adits in the area and field photographs of these features.

of Alaska that remains open to mineral entry. Both of these areas are characterized by extensive boreal forest cover, masking many of the geologic outcrops that could point the way toward potential ore deposits. Therein lies the promise of developing protocols for integrating airborne LiDAR into standard mineral exploration strategies. Finally, it is important to emphasize the symbiotic possibilities between applying LiDAR to mineral exploration and the larger issue of LiDAR as a component of public infrastructure. To date, most airborne LiDAR surveys have been conducted as components of academic research projects underwritten by state and municipal governments, which use the data for urban planning, transportation, and flood plain mapping purposes, or by land management agencies, such as the U.S. Forest Service, which use them for specialized projects such as timber sales. Demonstrating the utility of LiDAR as a tool for mineral exploration could broaden overall public support for greater acquisition of these data, which could then be used by both private and public entities. The so-called Elevation for the Nation initiative (National Research Council, 2007) is one such far-reaching possibility.

interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. government. Assistance in the field was provided by Ryan Hamilton and Kimberlee Pulsipher. Aid in understanding LiDAR processing was provided by Mike Boeder, Watershed Sciences, Inc. The manuscript was improved by comments from Brian Hoal, Colin Barnett, and Jennifer Ellis. REFERENCESAllen, Jr., R.M., 1951, Structural control of some gold-base metal veins in eastern Grant County, Oregon: Economic Geology, v. 46, p. 398403. Baker, A.A., Calkins, F.C., Crittenden, Jr., M.D., and Bromfield, C.S., 1966, Geologic map of the Brighton quadrangle, Utah: U.S. Geological Survey Quadrangle Map GQ-534. Borg, G., Krner, K., Buxton, M., Armstrong, R., and van der Merwe, S.W., 2003, Geology of the Skorpion supergene zinc deposit, southern Namibia: Economic Geology, v. 98, p. 749771. Boutwell, J.M., 1912, Geology and ore deposits of the Park City district, Utah: U.S. Geological Survey Professional Paper 77, p. 218225. Bromfield, C.S., 1989, Gold deposits in the Park City mining district, Utah: U.S. Geological Survey Bulletin 1857-C, p. C14C26. Butler, B.S., 1913, Geology and ore deposits of the San Francisco and adjacent districts, Utah: U.S. Geological Survey Professional Paper 80, 212 p. Calkins, F.C., and Butler, B.S., 1943, Geology and ore deposits of the Cottonwood-American Fork area, Utah: U.S. Geological Survey Professional Paper 201, 152 p. Callaghan, E., and Buddington, A.F., 1938, Metalliferous mineral deposits of the Cascade Range, Oregon: U.S. Geological Survey Bulletin 893, 141 p.

ACKNOWLEDGMENTSThis research was supported by the U.S. Geological Survey (USGS), Department of the Interior, under USGS award no. G11AP20050. The views and conclusions contained in this document are those of the authors and should not be

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G E O M E T A L L U R G Y F O R U M Geometallurgy in Advanced ExplorationJ. Jackson and K. Olson Hoal (SEG 1998 F) SEG NEWS

The Geometallurgy Forum is a regular feature of the SEG Newsletter. Questions about contributing to this column should be sent to Steve Williams (stevewilliams@geomettech.com). Questions by economic geologists involved in advanced exploration and feasibility studies commonly revolve around the issues of why and when a geometallurgical program should commence and what should it consist of. In this article, I will try to address these questions and outline the benefits of such a program. The focus of mineral exploration is on finding and proving sufficient quantities of mineralization that is viable to be exploited and, hence, classified as ore. From an economic geologists perspective, we believe there are two main facets to mineral exploration: a genetic facet, focused on the ore deposit/exploration model, and an extraction facet, focused on the economic extraction of the valuable minerals, which includes mineral processing/metallurgy and engineering. This later facet was noted as important for the economic geologist in the inaugural 1905 issue of Economic Geology by both Ransome1 and Irving,2 and is the foundation of the geometallurgical approach. Just as understanding the shape, extent, grades, and alteration/mineralization distribution is important to deposit knowledge, the understanding of issues related to the processibility (extraction, mineral processing, mining, environmental issues) of the material has a significant impact on the economics of the project. Just as building knowledge of the genetic aspects takes time and analysis, so does building knowledge of the processibility, including addressing any problems. Hence, for a greenfields prospect, our view is that a formal geomet program should commence in the advanced exploration stage, when drilling indicates that the project is likely to go to an order-of-magnitude or scoping study. Data, information, and knowledge, useful in screening potential extraction processibility issues, have usually been obtained through the genetic studies, particularly information on alteration events and mineralization styles. Once the processes to be investigated have been determined, our preferred approach is to apply small-scale tests that give an1 Ransome, F.L., 1905, The present standing of applied geology: Economic Geology, v. 1, p. 110. 2 Irving, J.D., 1905, University training of engineers in economic geology: Economic Geology, v. 1, p. 7782.

indication of process performance, coupled with geological investigations on two to three key sections prior to any significant drill out. The objective here is to assess the relative variability of the processes under consideration and understand the geological drivers of the relative performance to determine the levels of future geomet sampling protocols required and performance risks for the relevant extraction processes, leading to definition of process-specific material types as outlined in the following figure.

An example is shown below where, for what was defined as an ore type, the samples with lower copper recovery, shown in orange, are dependent on 2 to 3% more pyrite than those shown in blue.

At the very least, the implementation of a geomet program at an early stage ensures that the sampling locations for future metallurgical test work programs reflect the potential variability, impact, and some knowledge of the spatial distribution of process performance. However, it also allows for changes in geological logging and/or data acquisition methods that relate to key extraction processes to be incorporated into standard practice. The longer it is left to be done, the more difficult undertaking retrospective data acquisition or relogging becomes, and the options for influencing processing become more limited. Prefeasibility and feasibility studies are commonly schedule driven, leaving little time for investigation and improved understanding. Common cases that we have observed where the early refinement of geological logging practices would have greatly assisted in the prediction of extraction process performance include the following: consistent and relevant alteration style and intensity for comminution (crush and grind) performance, alteration style and intensity plus fracture style and density for blasting, and sulfide mineralogy for flotation performance and acid rock drainage.

Many junior companies raise the very valid issue that as a mineral resource (focused on tonnes and grade) is the measure upon which the company is rated by the market, there is great pressure to define the resource as soon as possible, and undertaking a geometallurgical program in early stages costs both time and moneythey would prefer to wait until there is a significant resource before committing to process-type tests. Another common issue raised is the fear of negative results and the impact in the market. However, by knowing problematic issues early, the focus of expenditure or the rate of expenditure can be adjusted and efforts made to unlock the value before significant funds have been spent, and then the negative results become apparent sooner. The upside is that as the key technical assumptions and risks are addressed, transparency and investor confidence is increased. In the case of those looking to fund development through JV, takeover, etc., one would expect a higher price and faster transaction in comparison to a similar opportunity without a geomet program. Additionally, more and more growth-focused companies are requesting geometallurgical analysis in advance of project acquisition and evaluation. A fully integrated geometallurgical approach can provide a sufficient level of knowledge for better process design across the value chain and review the robustness of the design under various scenarios, hence providing more confidence in the subsequent choice of project development and optimization, with the potential to unlock significant value. 1

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