Open Pit Mine - Planning and Design-3rd Edition

Open Pit Mine - Planning and Design-3rd Edition

(Parte 1 de 7)

OPEN PIT MINE PLANNING & DESIGN VOLUME 1 - FUNDAMENTALS i i

PLANNING & DESIGN Volume 1 - Fundamentals

Professor Emeritus, Department of Mining Engineering, University of Utah, Salt Lake City, Utah, USA

Associate Professor, Department of Mining Engineering, Colorado School of Mines, Golden, Colorado, USA

R. MARTIN President, R.K. Martin and Associates, Inc., Denver, Colorado, USA

CRC Press Taylor & Francis Group Boca Raton London New York Leiden

CRC Press is an imprint of the Taylor & Francis Group, an informa business

Cover photo credit: Bingham Canyon mine, courtesy of Kennecott Utah Copper

Library of Congress Cataloging-in-Publication Data

Applied for

1st edition, 1st print: 1995 2nd print: 1998 Revised and extended 2nd edition: 2006 Revised and extended 3rd edition: 2013

Copyright © 2006 Taylor & Francis pic., London, UK

Typeset by MPS Limited, Chennai, India Printed and bound in Great Britain by CPI Group (UK) Ltd, Croydon, CR0 4YY.

All rights reserved. No part of this publication or the information contained herein may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, by photocopying, recording or otherwise, without written prior permission from the publishers.

Although all care is taken to ensure the integrity and quality of this publication and the information herein, no responsibility is assumed by the publishers nor the authors for any damage to property or persons as a result of operation or use of this publication and/or the information contained herein.

Published by: CRC Press/Balkema

P.O. Box 11320, 2301 EH, Leiden, The Netherlands e-mail: Pub.NL@taylorandfrancis.com w.crcpress.com - w.taylorandfrancis.com

Paperback edition Complete set of two volumes plus CD-ROM: ISBN: 978-1-4665-7512-7

Contents

PREFACE xv ABOUT THE AUTHORS xix

1 MINE PLANNING 1

1.1 Introduction 1 1.1.1 The meaning of ore 1 1.1.2 Some important definitions 2 1.2 Mine development phases 5 1.3 An initial data collection checklist 7 1.4 The planning phase 1 1.4.1 Introduction 1

1.4.2 The content of an intermediate valuation report 12 1.4.3 The content of the feasibility report 12 1.5 Planning costs 17 1.6 Accuracy of estimates 17 1.6.1 Tonnage and grade 17 1.6.2 Performance 17 1.6.3 Costs 18 1.6.4 Price and revenue 18

1.7 Feasibility study preparation 19 1.8 Critical path representation 24 1.9 Mine reclamation 24 1.9.1 Introduction 24 1.9.2 Multiple-use management 25 1.9.3 Reclamation plan puipose 28 1.9.4 Reclamation plan content 28 1.9.5 Reclamation standards 29 1.9.6 Surface and ground water management 31 1.9.7 Mine waste management 32 1.9.8 Tailings and slime ponds 3 1.9.9 Cyanide heap and vat leach systems 3 1.9.10 Landform reclamation 34 vin Open pit mine planning and design: Fundamentals

1.10 Environmental planning procedures 35 1.10.1 Initial project evaluation 35 1.10.2 The strategic plan 37 1.10.3 The environmental planning team 38 1.1 A sample list of project permits and approvals 40

References and bibliography 40 Review questions and exercises 43

2 MINING REVENUES AND COSTS 47

2.1 Introduction 47 2.2 Economic concepts including cash flow 47 2.2.1 Future worth 47 2.2.2 Present value 48 2.2.3 Present value of a series of uniform contributions 48 2.2.4 Payback period 49

2.2.5 Rate of return on an investment 49 2.2.6 Cash flow (CF) 50 2.2.7 Discounted cash flow (DCF) 51 2.2.8 Discounted cash flow rate of return (DCFROR) 51 2.2.9 Cash flows, DCF and DCFROR including depreciation 52 2.2.10 Depletion 53 2.2.1 Cash flows, including depletion 5 2.3 Estimating revenues 56 2.3.1 Current mineral prices 56 2.3.2 Historical price data 64 2.3.3 Trend analysis 75 2.3.4 Econometric models 91 2.3.5 Net smelter return 92 2.3.6 Price-cost relationships 9 2.4 Estimating costs 100 2.4.1 Types of costs 100 2.4.2 Costs from actual operations 101

2.4.3 Escalation of older costs 126 2.4.4 The original O'Hara cost estimator 131 2.4.5 The updated O'Hara cost estimator 134 2.4.6 Detailed cost calculations 152 2.4.7 Quick-and-dirty mining cost estimates 167 2.4.8 Current equipment, supplies and labor costs 168 References and bibliography 175 Review questions and exercises 181

3 OREBODY DESCRIPTION 186

3.1 Introduction 186 3.2 Mine maps 186 3.3 Geologic information 201

Contents vii

3.4 Compositing and tonnage factor calculations 205 3.4.1 Compositing 205 3.4.2 Tonnage factors 211 3.5 Method of vertical sections 216 3.5.1 Introduction 216 3.5.2 Procedures 216 3.5.3 Construction of a cross-section 217 3.5.4 Calculation of tonnage and average grade for a pit 221

3.6 Method of vertical sections (grade contours) 230 3.7 The method of horizontal sections 237

3.7.1 Introduction 237 3.7.2 Triangles 237

3.7.3 Polygons 241 3.8 Block models 245 3.8.1 Introduction 245 3.8.2 Rule-of-nearest points 248 3.8.3 Constant distance weighting techniques 249 3.9 Statistical basis for grade assignment 253 3.9.1 Some statistics on the orebody 256 3.9.2 Range of sample influence 260 3.9.3 Illustrative example 261 3.9.4 Describing variograms by mathematical models 266 3.9.5 Quantification of a deposit through variograms 268 3.10 Kriging 269 3.10.1 Introduction 269 3.10.2 Concept development 270

3.10.3 Kriging example 272 3.10.4 Example of estimation for a level 276

3.10.5 Block kriging 276 3.10.6 Common problems associated with the use of the kriging technique 277 3.10.7 Comparison of results using several techniques 278 References and bibliography 279 Review questions and exercises 286

4 GEOMETRICAL CONSIDERATIONS 290

4.1 Introduction 290 4.2 Basic bench geometry 290 4.3 Ore access 297 4.4 The pit expansion process 310 4.4.1 Introduction 310 4.4.2 Frontal cuts 310 4.4.3 Drive-by cuts 313 4.4.4 Parallel cuts 313 4.4.5 Minimum required operating room for parallel cuts 316 4.4.6 Cut sequencing 322 vin Open pit mine planning and design: Fundamentals

4.5 Pit slope geometry 323 4.6 Final pit slope angles 332 4.6.1 Introduction 332 4.6.2 Geomechanical background 3 4.6.3 Planar failure 334 4.6.4 Circular failure 340 4.6.5 Stability of curved wall sections 340 4.6.6 Slope stability data presentation 342 4.6.7 Slope analysis example 343 4.6.8 Economic aspects of final slope angles 344 4.7 Plan representation of bench geometry 346 4.8 Addition of a road 350 4.8.1 Introduction 350 4.8.2 Design of a spiral road - inside the wall 356 4.8.3 Design of a spiral ramp - outside the wall 361 4.8.4 Design of a switchback 364

4.8.5 The volume represented by a road 367 4.9 Road construction 372 4.9.1 Introduction 372 4.9.2 Road section design 373 4.9.3 Straight segment design 378 4.9.4 Curve design 381 4.9.5 Conventional parallel berm design 384 4.9.6 Median berm design 384 4.9.7 Haulage road gradients 385 4.9.8 Practical road building and maintenance tips 388 4.10 Stripping ratios 389 4.1 Geometric sequencing 394 4.12 Summary 397

References and bibliography 397 Review questions and exercises 404

5 PIT LIMITS 409

5.1 Introduction 409 5.2 Hand methods 410 5.2.1 The basic concept 410 5.2.2 The net value calculation 413 5.2.3 Location of pit limits - pit bottom in waste 419 5.2.4 Location of pit limits - pit bottom in ore 425

5.2.5 Location of pit limits - one side plus pit bottom in ore 425 5.2.6 Radial sections 426 5.2.7 Generating a final pit outline 432 5.2.8 Destinations for in-pit materials 437 5.3 Economic block models 439 5.4 The floating cone technique 441 5.5 The Lerchs-Grossmann 2-D algorithm 450

Contents ix

5.6 Modification of the Lerchs-Grossmann 2-D algorithm to a 2V2-D algorithm 459 5.7 The Lerchs-Grossmann 3-D algorithm 462 5.7.1 Introduction 462 5.7.2 Definition of some important terms and concepts 465

5.7.3 Two approaches to tree construction 468 5.7.4 The arbitrary tree approach (Approach 1) 469 5.7.5 The all root connection approach (Approach 2) 471 5.7.6 The tree 'cutting' process 475 5.7.7 A more complicated example 477

5.8 Computer assisted methods 478 5.8.1 The RTZ open-pit generator 478 5.8.2 Computer assisted pit design based upon sections 484 References and bibliography 496 Review questions and exercises 501

6 PRODUCTION PLANNING 504

6.1 Introduction 504 6.2 Some basic mine life - plant size concepts 505 6.3 Taylor's mine life rule 515 6.4 Sequencing by nested pits 516 6.5 Cash flow calculations 521 6.6 Mine and mill plant sizing 533 6.6.1 Ore reserves supporting the plant size decision 533 6.6.2 Incremental financial analysis principles 537

6.6.3 Plant sizing example 540 6.7 Lane's algorithm 548 6.7.1 Introduction 548 6.7.2 Model definition 549 6.7.3 The basic equations 550 6.7.4 An illustrative example 551 6.7.5 Cutoff grade for maximum profit 552

6.7.6 Net present value maximization 560 6.8 Material destination considerations 578 6.8.1 Introduction 578 6.8.2 The leach dump alternative 579

6.8.3 The stockpile alternative 584 6.9 Production scheduling 590 6.9.1 Introduction 590 6.9.2 Phase scheduling, 602

6.9.3 Block sequencing using set dynamic programming 608 6.9.4 Some scheduling examples 620

6.10 Push back design j 626 6.10.1 Introduction 626 6.10.2 The basic manual steps 633

6.10.3 Manual push back design example 635 vin Open pit mine planning and design: Fundamentals

6.10.4 Time period plans 647 6.10.5 Equipment fleet requirements 649 6.10.6 Other planning considerations 651 6.1 The mine planning and design process - summary and closing remarks 653

References and bibliography 655 Review questions and exercises 6

7 REPORTING OF MINERAL RESOURCES AND ORE RESERVES 670

7.1 Introduction 670 7.2 The JORC code - 2004 edition 671 7.2.1 Preamble 671 7.2.2 Foreword 671 7.2.3 Introduction 671 7.2.4 Scope 675

7.2.5 Competence and responsibility 676

7.2.6 Reporting terminology 678 7.2.7 Reporting - General 679 7.2.8 Reporting of exploration results 679 7.2.9 Reporting of mineral resources 680 7.2.10 Reporting of ore reserves 684 7.2.1 Reporting of mineralized stope fill, stockpiles, remnants, pillars, low grade mineralization and tailings 687

7.3 The CIM best practice guidelines for the estimation of mineral resources and mineral reserves - general guidelines 688 7.3.1 Preamble 688 7.3.2 Foreword 688 7.3.3 The resource database 690 7.3.4 Geological interpretation and modeling 692 7.3.5 Mineral resource estimation 695

7.3.6 Quantifying elements to convert a Mineral Resource to a Mineral Reserve 698 7.3.7 Mineral reserve estimation 700 7.3.8 Reporting 702 7.3.9 Reconciliation of mineral reserves 706 7.3.10 Selected references 709 References and bibliography 709 Review questions and exercises 713

8 RESPONSIBLE MINING 716

8.1 Introduction 716 8.2 The 1972 United Nations Conference on the Human

Environment 717 8.3 The World Conservation Strategy (WCS) - 1980 721 8.4 World Commission on Environment and Development (1987) 724

Contents xi

8.5 The 'Earth Summit' 726 8.5.1 The Rio Declaration 726 8.5.2 Agenda 21 729 8.6 World Summit on Sustainable Development (WSSD) 731 8.7 Mining industry and mining industry-related initiatives 732 8.7.1 Introduction 732 8.7.2 The Global Mining Initiative (GM3) 732 8.7.3 International Council on Mining and Metals (ICMM) 734 8.7.4 Mining, Minerals, and Sustainable Development (MMSD) 736 8.7.5 The U.S. Government and federal land management 737

8.7.6 The position of the U.S. National Mining Association (NMA) 740 8.7.7 The view of one mining company executive 742 8.8 'Responsible Mining' - the way forward is good engineering 744 8.8.1 Introduction 744 8.8.2 The Milos Statement 744

8.9 Concluding remarks 747

References and bibliography 747 Review questions and exercises 754

9 ROCK BLASTING 757

9.1 General introduction to mining unit operations 757 9.2 Rock blasting 758 9.2.1 Rock fragmentation 758 9.2.2 Blast design flowsheet 759

9.2.3 Explosives as a source of fragmentation energy 761 9.2.4 Pressure-volume curves 762

9.2.5 Explosive strength 765 9.2.6 Energy use 766 9.2.7 Preliminary blast layout guidelines 767 9.2.8 Blast design rationale 768 9.2.9 Ratios for initial design 774 9.2.10 Ratio based blast design example 775 9.2.1 Determination of K 780 9.2.12 Energy coverage 782

9.2.13 Concluding remarks 788 References and bibliography 788 Review questions and exercises 792

10 ROTARY DRILLING 796

10.1 Brief history of rotary drill bits 796 10.2 Rock removal action 800

10.3 Rock bit components 808 10.4 Roller bit nomenclature 810 10.5 The rotary blasthole drill machine 816 10.6 The drill selection process 823 10.7 The drill string 824 vin Open pit mine planning and design: Fundamentals

10.8 Penetration rate - early fundamental studies 832 10.9 Penetration rate - field experience 837

10.10 Pulldown force 845 10.1 Rotation rate 847 10.12 Bit life estimates 848 10.13 Technical tips for best bit performance 849 10.14 Cuttings removal and bearing cooling 849 10.15 Production time factors 857 10.16 Cost calculations 858 10.17 Drill automation 860

References and bibliography 860 Review questions and exercises 869

1 SHOVEL LOADING 875

1.1 Introduction 875 1.2 Operational practices 878 1.3 Dipper capacity 879 1.4 Some typical shovel dimensions, layouts and specifications 880 1.5 Ballast/counterbalance requirements 882 1.6 Shovel production per cycle 883 1.7 Cycle time 886 1.8 Cycles per shift 889 1.9 Shovel productivity example 893 1.10 Design guidance from regulations 894

References and bibliography 895 Review questions and exercises 897

12 HAULAGE TRUCKS 900

12.1 Introduction 900 12.2 Sizing the container 900

12.3 Powering the container 902 12.4 Propeling the container - mechanical drive systems 903 12.4.1 Introduction 903 12.4.2 Performance curves 905 12.4.3 Rimpull utilization 912 12.4.4 Retardation systems 917

12.4.5 Specifications for a modern mechanical drive truck 923 12.4.6 Braking systems 927

12.5 Propelling the container - electrical drive systems 929 12.5.1 Introduction 929 12.5.2 Application of the AC-drive option to a large mining truck 930

12.5.3 Specifications of a large AC-drive mining truck 932 12.5.4 Calculation of truck travel time 933

12.6 Propelling the container - trolley assist 937 12.6.1 Introduction 937 12.6.2 Trolley-equipped Komatsu 860E truck 938

Contents xiii

12.6.3 Cycle time calculation for the Komatsu 860E truck with trolley assist 939 12.7 Calculation of truck travel time - hand methods 939 12.7.1 Introduction 939 12.7.2 Approach 1 - Equation of motion method 941 12.7.3 Approach 2 - Speed factor method 951 12.8 Calculation of truck travel time - computer methods 956 12.8.1 Caterpillar haulage simulator 956 12.8.2 Speed-factor based simulator 957

12.9 Autonomous haulage 958

References and bibliography 964 Review questions and exercises 969

13 MACHINE AVAILABILITY AND UTILIZATION 972

13.1 Introduction 972 13.2 Time flow 973 13.3 Availability - node 1 975 13.4 Utilization - node 2 977 13.5 Working efficiency - node 3 978 13.6 Job efficiency - node 4 978 13.7 Maintenance efficiency - node 5 979 13.8 Estimating annual operating time and production capacity 980 13.9 Estimating shift operating time and production capacity 983 13.10 Annual time flow in rotary drilling 987

(Parte 1 de 7)

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