Proceedings of the Second International Conference on Heap Leach Solutions, 2014 Editors Dirk van Zyl, PhD, PE University of British Columbia and InfoMine Inc., Canada Igor Gonzáles Galindo Board Member Cia. Minas Buenaventura, Hudbay Minerals, and Sierra Metals, Peru Copyright © Copyright 2014, InfoMine Inc. All rights reserved. No part of this publication may be reproduced, stored or transmitted in any form without the prior permission of InfoMine Inc., Canada. Disclaimer All views and opinions expressed in the articles published in these Proceedings are those of the authors, and do not necessarily represent those of InfoMine Inc., or of the technical committee, or of the editors. The authors take full and exclusive responsibility for technical content and accuracy of the content published herein, and reproduced in any corresponding online content. This information is not intended nor implied to be a substitute for professional advice. InfoMine Inc. and the editors are not responsible for any damage to property or persons that may occur as a result of the use of the information contained in this volume and in any accompanying online content. Finally, all efforts have been made to obtain publication quality illustrations, but in some cases, this has not been possible. Production Joe Goodwill InfoMine Inc., Canada ISBN: 978-0-9917905-6-2 InfoMine Inc. Suite 900 580 Hornby Street Vancouver British Columbia Canada Telephone: +1 604 683 2037 [email protected] www.InfoMine.com ii InfoMine Inc. InfoMine Inc. is the world leader in providing mining knowledge online, delivering content via our website, through corporate intranets, and by email. The InfoMine websites provide focused, in-depth information and functionality encompassing most aspects of mining and mineral exploration activities worldwide. The websites are organized as a series of InfoMine Editions which collectively provide access to the largest, most fully integrated source of worldwide mining and mineral exploration information. Each InfoMine Edition has its own specific audience and content provided in the local language. Whether one is developing mineral properties, investing in mining, or selling products and services, industry research and knowledge are vital. Reliable, focused information is necessary to keep a competitive advantage, and InfoMine is equipped to conveniently provide the requisite knowledge. ConferenceMine ConferenceMine, the InfoMine conferences division, organizes highly technical seminars and conferences, addressing specialized topics for the purpose of technology and knowledge transfer. InfoMine conferences provide an opportunity for specialists and technology users to exchange information, discuss the latest research and propose innovative solutions to technical challenges. 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Minas Buenaventura, Hudbay Minerals, and Sierra Metals, Peru Co-Chairs Dirk van Zyl, PhD, PE, University of British Columbia and InfoMine Inc., Canada Jaime Arana, Projects Director, Southern Peru Copper Corporation, Peru Guillermo Canchis, Crushing and Leaching Hydrometallurgy Process Superintendent, Sociedad Minera Cierro Verde S.A.A., Peru Augusto Chung, Project Director Phase 2, Rio Alto S.A.C., Peru Conference Manager Olga Cherepanova, InfoMine Inc., Canada Conference Coordinators Ursula Alvarado, InfoMine Operations Peru, Peru Susana Perez, InfoMine Inc., Canada Technical Publisher Joe Goodwill, InfoMine Inc., Canada Technical Advisor Andy Robertson, PhD, InfoMine Inc. and Robertson GeoConsultants, Canada Advisory Committee David Arcos, Manager, Mining Geochemistry, Amphos 21 Consulting, Spain José Ale, Geotechnical Engineer, AMEC Environment and Infrastructure Peru, Peru Nathan W. Haws, Supervising Engineer, MWH Global, USA Jim McCord, Technical Director Water Resources, South America, AMEC Environment and Infrastructure Peru, Peru Mike Milczarek, President, GeoSystems Analysis, USA Denys Parra, General Manager, Anddes Asociados, Peru Eduardo Ruiz, General Manager, Amphos 21 Peru, Peru Michael Shelbourn, Manager, Geotechnical Engineering, Corporate Environment Dpt, Barrick Gold Corp., USA Franςois Swanepoel, Head of Engineering, Exploration–Americas Region, Gold Fields La Cima, Peru v vi Foreword Heap Leach Solutions 2014 was hosted in Lima, Peru. InfoMine was proud to be the organizer of the second in this international series of conferences, as well as the publisher of this volume. This series of conferences aims to include contributions from the broad spectrum of disciplines that must work together to develop economically and technically successful heap leach projects—and this volume represents a collection of papers that reflects that. Topics vary from detailed geotechnical concerns in the design and construction of heap leach pads, to characterization of ores in the laboratory and in situ, to the successful operation of heap leach operations, including processing plants. Many technologies are highlighted in the papers contained in this volume. These are focused on improving design, construction, and operation of heap leach projects. A number of papers on cost estimation of heap leach pads are included, providing very good guidance to engineers in this area. Overall this volume contributes to the global knowledge in heap leaching. In total this volume contains thirty-five excellent papers that will be a reference source in the future. We are pleased to have two papers by Mr. Randy Scheffel on the important topic of Achieving the correct conceptual design. The first of these was presented at the II International Meeting Metallurgy Peru 2013: Plants and Processes, 1, 2, and 3 in Lima in 2013. The organizer of that conference, Alfredo Olaya, was kind enough to give permission for inclusion of that paper in this volume. InfoMine appreciates that as it allows readers of this volume to have access to the complete work. The significance of Randy Scheffel’s contribution to the profession in these two papers, based on a professional career focused on heap leaching, cannot be overstated. These papers will become required reading for all young heap leach engineers, as well as those who need to remind themselves of the basic concepts in the design of these projects. This volume reflects an excellent cross section of papers about heap leaching practices that were the focus of this year’s conference. We believe it makes a significant contribution to the literature in this area. Dirk van Zyl, PhD, PE Organizing Committee Co-Chair, Heap Leach 2014, Lima, Peru vii Sponsors and Exhibitors Gold Sponsor Silver Sponsor Coffee Break Sponsor Lanyard Sponsor This list was up-to-date as of October 29, 2014 viii Institutional Partners Exhibitors This list was up-to-date as of October 29, 2014 ix Media Sponsor Media Partners This list was up-to-date as of October 29, 2014 x Contents Chapter 1: Heap leach development—Achieving the correct conceptual design Heap leach development—Achieving the correct conceptual design—Part I | Randolph E. Scheffel ................. 3 Heap leach development—Achieving the correct conceptual design—Part 2 | Randolph E. Scheffel ............. 31 Chapter 2: Heap Leach Projects Kişladağ Gold Mine heap leach facility | Veli Gökdere, H. Nejat Utkucu, Jale Sakiyan Ates, and Omer Kahraman ............................................................................................................................................ 57 Chapter 3: Leach Pad Costing and Ore Stacking Leach pad cost benchmarking | Mark E. Smith and Denys Parra .............................................................................. 69 A procedure to estimate the differences in heap leaching costs brought about through variations in climate and terrain | Scott Stebbins ............................................................................................................. 79 Leach pad equipment for greater production | Karl Ingmarsson .............................................................................. 91 Design considerations for mobile stacking conveyors for challenging terrain and climate conditions | Grant Graber and Ron Kelly .................................................................................................... 105 Chapter 4: Modeling and Closure Utilizing CFD technology to capture multi-dimensional thermal-fluid-reactive phenomena in a heap leach operation | D. McBride, J.E. Gebhardt, and M. Cross .......................................................... 121 Conceptual cover system design for heap leach closure | Lindsay Tallon, Mike O'Kane, and Brian Ayres .. 133 The application of unsaturated soil mechanics to heap leach analysis | J. Stianson and D.G. Fredlund ........ 141 The design and water balance of precious metal heap leach projects under extreme rainfall variation using METSIM® | Calvin Morrison, Ashraf Jaffer, and Alex Holtzapple ............................... 153 Chapter 5: Drain Systems under High Loads Geomembrane and pipe design issues in deeper heap leach pads | Carlos César, Denys Parra, and Javier Mendoza .........................................................................................................................................