Table Of ContentTechniques in
Underground Mining
Selections from Underground Mining Methods Handbook
Edited by Richard E. Gertsch and Richard L. Bullock
Published by the
Society for Mining, Metallurgy, and Exploration
Copyright 0 1998 Society for Mining, Metallurgy, and Exploration, Inc.
All Rights Reserved
Printed in the United States of America
No part of this publication may be reproduced, stored in a retrieval system, or transmitted
in any form or by any means, electronic, mechanical, photocopying, recording, or
otherwise, without the prior written permission of the publisher.
Society for Mining, Metallurgy, and Exploration, Inc.
PO Box 625002
Littleton, CO, USA 80162-5002
303-973-9550
ISBN 978-0-87335-163-8
Library of Congress Cataloging-in-PublicationD ata
Techniques in underground mining : selections from Underground
mining methods handbook / edited by Richard E. Gertsch and
Richard L. Bullock.
836 p. 21.6 x 27.9 cm.
Includes bibliographical references and index.
ISBN 978-0-87335-163-8 (he)
1. Mining engineering. I. Gertsch, Richard E. 11. Bullock,
.
Richard Lee, 1929- 111. Society for Mining, Metallurgy, and
Exploration (U.S.) Iv. Underground mining methods handbook.
TN275T33 1998
622.2--dc21 98-28643
CIP
..............
Preface
Considered a shrinking industry in the late 1980s and early 1990s, under-
ground mining is now experiencing a revival. Unfortunately, there is a void of
material that adequately addresses the important mining methods and opera-
tional techniques needed by both mining engineering students and industry
professionals. As a temporary solution, the original Underground Mining
Methods Handbook (published in 1982 and now out of print) has been con-
densed in this new version, Techniques in Underground Mining-Selections
From the Underground Mining Methods Handbook.
The discriminating reader will question why the editors included or excluded
certain sections from the original. To assist the editors, guidelines were estab-
lished to produce an inexpensive volume that would include descriptions of
underground methods for mining students.
The guidelines followed by the editors were:
include only those sections that address and describe underground mining
methods;
limit the mining methods to noncoal mining methods;
reduce the text to one-third of the original text; and
make no revisions to sections or chapters (although deletions within a
chapter were allowed if it improved the chapter).
The editors excluded sections and chapters that covered equipment, coal min-
ing, rock fragmentation, rock mechanics and ground control methods, venti-
lation, economic evaluation, financial consideration, and exploration. These
subjects are covered in other available texts.
One mining method-the use of timber support- extensively covered in the
original book had to be deleted in order to meet the page limit guideline.
Although timbering is mines is still important, particularly in drifting, there is
a definite trend away from mining methods requiring timber as the main sup-
port. Thus, this method is not included in this version.
vii
Although many chapters on mining equipment in the original handbook are
still applicable, many others are obsolete. The change from pneumatic to
hydraulic drills is a good example. Since updated information is available
from other sources, mining equipment is not included.
Chapters on economics and cost considerations were a compromise. The
sections that originally stood alone were eliminated. However, the cost
analysis that accompany the mining methods are included, even though the
costs are 15 years out of date. The methods used to calculate costs are worth
preserving and the actual updated costs could easily be substituted into that
methodology.
The introductory section was also a compromise. The editors decided to leave
in enough material to introduce the subject and to provide adequate
discussions of engineering matters unique to underground mining, although
somewhat shared with surface mining, including sampling, reserve analysis,
and planning.
Reprinting a condensed version of the Underground Mining Methods Hand-
book is only a temporary solution to the problem of providing an updated text
on underground mining methods. A completely new version must soon be
written. This version should include updates to all the mining method
changes, particularly those changed in vertical crater retreat, undercut and fill
with high-density cemented or paste backfill, in-situ or solution mining, and
hardrock longwall mining methods. It seems unlikely that any new work will
encompass the sweeping range of topics covered in the 1982 original. Thus,
any new handbook will likely cover several volumes.
Richard Gertsch
Richard Bullock
viii
. . . . . . . . . . . . . .
Contents
FOREWORD xi
PREFACE xiii
SECTION 1 OVERVIEW 1
Ore Reserve Calculation
Leigh A. Readdx David S. Bolin, and Graham A. Mathieson 3
Choosing an Underground Mining Method
HamHamrin 45
General Mine Planning
Richard L. Bullock 87
Sampling, Dilution, and Recovery
C. Alan Tapp 129
SECTION 2 METHODS REQUIRING MINIMUM SUPPORT 157
Room-and-Pillar Method of Open-Stope Mining
Richard L. Bullock 159
Production Methods of Noncoal Room-and-Pillar Mining
Richard L. Bullock 171
Open Stope Mining at the Magmont Mine, Bixby, Missouri
G.D. Bates 215
Sublevel Stoping
C. David Mann 223
Considerations for Sublevel Stoping
Brian W. Lawrence 227
iii
Excavation Design and Mining Methods in the 1100 Orebody, Mount Isa
Mine, Australia
B. Hornsby and B.J.K. Sullivan 249
Strissa Mine
K.-A. Bjorkstedt 275
Sublevel Stoping at the EB Massive Reefs at Loraine Gold Mines, Ltd.
RD.H. Bebb 311
Large Blasthole Stoping at Rodsand Gruber, Norway
Tore M. Larsen 321
Vertical Crater Retreat: An Important Mining Method
L.C. Lang 329
Crater Blasting Method Applied to Pillar Recovery at Falconbridge Nickel
Mines Ltd.
C.J. Monahan 343
Cost Calculations for Sublevel Longhole Stoping
Gordon M. Pugh and David G. Rasmussen 353
Cost Estimation for Sublevel Stoping-A Case Study
A.J. Richardson 361
SECTION 3 STOPES REQUIRING ADDITIONAL SUPPORT OTHER THAN PILLARS 373
Shrinkage Stoping: An Introduction
William Lyman 375
Shrinkage Stoping at the Crean Hill Mine
K.J. Henderson 385
Shrinkage Stoping at the Idarado Mine
Compiled by WilliamA . Hustrulid 393
Cost Calculations for Mechanized Shrinkage Stoping
Gordon M. Pugh and David G. Rasmussen 421
Cut-and-Fill Stoping: An Introduction
Joel K. Waterland 439
Principles of Stope Planning and Layout for Ground Control
PA. MacMillian and B.A. Ferguson 445
Cut-and-Fill at Mount Isa Mines Ltd.
B. Hornsby and Stafjs Mount Isa Mines 455
The Zinc Corporation, Ltd., and New Broken Hill Consolidated, Ltd.
R.E. Le Messurier 469
Cut-and-FillS toping at Star Mine
Gordon Miner 485
Cut-and-Fill Stoping at Lucky Friday Mine
Stafi Lucky Friday Mine 495
iv
Cut-and-Fill at the Bruce Mine
Ronald T. Johnson, Keith E. mas, and John Nelson 503
Cut-and-Fill at Homestake Mining Co.
Joel K. Waterland and StaB Homestake Mining Co. 515
Cost Calculations for Highly Mechanized Cut-and-Fill Stoping
Gordon M. Pugh and David G. Rasmussen 525
Undercut-and-Fill Mining: An Introduction
J. W. Murray 557
Undercut-and-Fill Mining as Practiced by Homestake Mining Co.
AS. Winters 573
Undercut-and-Fill Mining at Falconbridge Mine of Falconbridge
Nickel Mines Ltd.
S.A. Tims 579
Cost Calculations for Underhand Cut-and-Fill Mining
Gordon M. Pugh and David G. Rasmussen 595
SECTION 4 SUBLEVEL CAVING 603
Sublevel Caving: An Introduction
E.W. Cokayne 605
The Mechanics and Design of Sublevel Caving Systems
Rudolf Kvapil 621
Sublevel Caving at Craigmont Mines Ltd.
R.A. Baase, W.D. Diment, andA.J. Petrina 655
Sublevel Caving at the Stobie Mine, Inco Metals Co.
G. W. Johnston 687
Sublevel Caving at LKAEJ’s Kiirunavaara Mine
H. Heden, K. Lidin, and R. Malmstrom 697
Planning Economics of Sublevel Caving
Dan Nilsson 725
SECTION 5 BLOCK AND PANEL CAVING 741
Block Caving: General Description
Ray L. Tobie and Douglas E. Julin 743
Climax Panel Caving and Extraction System
John C. Gould 755
San Manuel Mine
R.L. Tobie, LA. Thomas, and H.H. Richards 771
The Henderson Mine
William G. Doepken 783
INDEX 801
V
SECTION 1
Overview
1
. . . . . . . . . . . . . .
Ore Reserve Calculation
CHAPTER 1
Leigh A. Readdy, David S. Bolin, and Graham A. Mathieson
INTRODUCTION
The estimation of ore reserves is a process that begins with the earliest explo-
ration stages on a property and continues throughout any subsequent evalua-
tion and exploitation of the deposit. During exploration and preliminary
evaluation, the results of these reserve estimates constitute the basic data for
prefeasibility studies and economic analysis. The decision to continue explo-
ration and development or to abandon a prospect is often based upon these
studies.
During the active life of a mine, reserve computations are continuously
revised to assist in development planning, cost and efficiency analyses, qual-
ity control, and improvement of extraction and processing methods. Accurate
reserve estimates are also required when financing a project, purchasing or
selling a property, and for accounting purposes such as depletion and tax
calculation.
It is important to remember that the reliability of ore reserve estimates vanes
progressively through time as more and more information becomes available.
The lowest order of reliability of estimation of reserves exists at the time of
discovery. The maximum level of certainty concerning the ore reserves within
a deposit is reached when the deposit is completely mined out. Between these
two extremes are variable levels of certainty as to the tonnage and grade of
the resource. This is particularly true of that portion of the mineral resource
that constitutes the “minable reserve,” as this portion is dependent upon eco-
nomic as well as geological and technological factors.
In the following discussion, several of the factors affecting ore reserve compu-
tation and some of the commonly used methods of calculation are presented.
The first part of the discussion is confined to classical methods of hand calcu-
lation utilizing level maps and sections. The second part of the discussion pre-
sents an overview of somewhat more sophisticated methods of geostatistics
4 Ore Reserve Calculation
that have been developed within recent years. Geostatistical methods fre-
quently provide the best ore reserve estimates for many deposits. However, a
digital computer is required for such geostatistically derived estimates due to
the number and complexity of the computations involved. For many proper-
ties the classical nongeostatistical methods are adequate, particularly in the
early exploration stages. In fact, it is the author’sc ontention that even at those
properties where the geostatistical approach is employed for reserve estima-
tion, the geological and engineering staffs should prepare an estimate by tra-
ditional means. This provides an internal audit for the reserves and at the
same time requires a continuing close appraisal of geologic problems that
influence the presently known geostatistically estimated reserves and produc-
tion at the mine.
CLASSlFlCATlON OF ORE RESERVES
The definition and classification of ore reserves have varied over the period of
development of the modern mining industry. “Ore” is generally understood to
be any naturally occurring, in-place, mineral aggregate containing one or
more valuable constituents that may be recovered at a profit under existing
economic conditions. This definition ignores special situations, such as war-
time production, or those cases when an otherwise unprofitable deposit may
be exploited for political or social reasons.
Ore reserves are classified with respect to the confidence level of the estimate.
Traditionally, ore reserves have been classified as proven (measured), proba-
ble (indicated), possible, and inferred. Historically, proven ore has been
regarded as that which is “blocked out” (i.e., measured, sampled, and assayed
on four sides); probable ore as blocked on three sides; possible ore as blocked
on two sides; and inferred ore as ore-grade material that is known on only
one side.
The U.S. Bureau of Mines (USBM) has introduced the following ore reserve
classification:
Measured Ore
Measured ore is ore for which tonnage is computed from dimensions revealed
in outcrops, trenches, workings, and drill holes, and for which the grade is
computed from the results of detailed sampling. The sites for inspection, sam-
pling, and measurement are so closely spaced and the geologic character is so
well-defined that the size, shape, and mineral content are well established.
The computed tonnage and grade are judged to be accurate within stated lim-
its, and no such limit is judged to differ from the computed tonnage or grade
by more than 20%.
Indicated Ore
Indicated ore is ore for which tonnage and grade are computed partly from
specific measurements, samples, or production data and partly from projec-
tion for a reasonable distance on geologic evidence. The sites available for
