Principles of Mining - Valuation, Organization and Administration

Herbert Hoover

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The Project Gutenberg EBook of Principles of Mining, by Herbert C. HooverThis eBook is for the use of anyone anywhere at no cost and withalmost no restrictions whatsoever. You may copy it, give it away orre-use it under the terms of the Project Gutenberg License includedwith this eBook or online at www.gutenberg.netTitle: Principles of MiningValuation, Organization and AdministrationAuthor: Herbert C. HooverRelease Date: September 24, 2008 [EBook #26697]Language: English*** START OF THIS PROJECT GUTENBERG EBOOK PRINCIPLES OF MINING ***Produced by Robert J. HallPRINCIPLES OF MININGPublished by theMcGraw-Hill Book CompanyNew York Successors to the Book Departments of theMcGraw Publishing Company Hill Publishing Company Electrical World The Engineering and Mining JournalEngineering Record Power and The EngineerElectric Railway Journal American MachinistMetallurgical and Chemical EngineeringPRINCIPLES OF MININGVALUATION, ORGANIZATION AND ADMINISTRATIONCOPPER, GOLD, LEAD, SILVER, TIN AND ZINCBYHERBERT C. HOOVERMember American Institute of Mining Engineers, Mining and Metallurgical Society of America, Société des Ingénieurs Civils de France, Fellow RoyalGeographical Society, etc.First EditionFOURTH THOUSANDMcGRAW-HILL BOOK COMPANY239 WEST 39TH STREET, NEW YORKBOUVERIE STREET, LONDON, E.C.1909Page iiiPREFACE.This volume is a condensation of a series of lectures delivered in part at Stanford and in part at Columbia Universities.It is ...

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• Publié par: pohid
• Publié le: 08 décembre 2010
• Nombre de lectures: 21
• Langue: English

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The Project Gutenberg EBook of Principles of Mining,
by Herbert C. Hoover
This eBook is for the use of anyone anywhere at no
cost and with
almost no restrictions whatsoever. You may copy it,
give it away or
re-use it under the terms of the Project Gutenberg
License included
with this eBook or online at www.gutenberg.net
Title: Principles of Mining
Valuation, Organization and Administration
Author: Herbert C. Hoover
Release Date: September 24, 2008 [EBook #26697]
Language: English
*** START OF THIS PROJECT GUTENBERG EBOOK
PRINCIPLES OF MINING ***
Produced by Robert J. Hall
PRINCIPLES OF MINING
Published by the
McGraw-Hill Book Company
New York
Successors to the Book Departments of the
McGraw Publishing Co
Hill Publishing Company
mpany

The Engineering and Mining
Electrical World
Journal
Engineering Record Power and The Engineer
Electric Railway Journal American Machinist
Metallurgical and Chemical Engineering
PRINCIPLES OF MINING
VALUATION, ORGANIZATION AND
ADMINISTRATION
COPPER, GOLD, LEAD, SILVER, TIN AND ZINC
BY
HERBERT C. HOOVER
Member American Institute of Mining Engineers,
Mining and Metallurgical Society of America, Société
des Ingénieurs Civils de France, Fellow Royal
Geographical Society, etc.
First Edition
FOURTH THOUSAND
McGRAW-HILL BOOK COMPANY
239 WEST 39TH STREET, NEW YORK
BOUVERIE STREET, LONDON, E.C.
1909
Page iii PREFACE.
This volume is a condensation of a series of lectures
delivered in part at Stanford and in part at Columbia
Universities. It is intended neither for those wholly
ignorant of mining, nor for those long experienced in
the profession.The bulk of the material presented is the common
heritage of the profession, and if any one may think
there is insufficient reference to previous writers, let
him endeavor to find to whom the origin of our
methods should be credited. The science has grown
by small contributions of experience since, or before,
those unnamed Egyptian engineers, whose works
prove their knowledge of many fundamentals of mine
engineering six thousand eight hundred years ago. If I
have contributed one sentence to the accumulated
knowledge of a thousand generations of engineers, or
have thrown one new ray of light on the work, I shall
have done my share.
I therefore must acknowledge my obligations to all
those who have gone before, to all that has been
written that I have read, to those engineers with whom
I have been associated for many years, and in
particular to many friends for kindly reply to inquiry
upon points herein discussed.
Page v CONTENTS.
CHAPTER 1.
Valuation of Copper, Gold, Lead, Silver, Tin, and Zinc
Lode Mines
Determination of average metal content; sampling, as
say plans, calculations of averages, percentage of err
ors in estimate from sampling.

CHAPTER II.
Mine Valuation (Continued)
Calculation of quantities of ore, and classification of or
e in sight.

CHAPTER III.
Mine Valuation (Continued)
Prospective value. Extension in depth; origin and stru
ctural character of the deposit; secondary enrichment
; development in neighboring mines; depth of exhausti
on.
CHAPTER IV.
Mine Valuation (Continued)
Recoverable percentage of the gross assay value; pri
ce of metals; cost of production.

CHAPTER V.
Mine Valuation (Continued)
Redemption or amortization of capital and interest.

CHAPTER VI.
Mine Valuation (Continued)
Valuation of mines with little or no ore in sight; valuati
ons on second-hand data; general conduct of examin
ations; reports.

CHAPTER VII.
Development of Mines
Entry to the mine; tunnels; vertical, inclined, and com
bined shafts; location and number of shafts. Page vi

CHAPTER VIII.
Development of Mines (Continued)
Shape and size of shafts; speed of sinking; tunnels.

CHAPTER IX.
Development of Mines (Continued)
Subsidiary development: stations; crosscuts; levels; in
terval between levels; protection of levels; winzes and
rises. Development in the prospecting stage; drilling.

CHAPTER X.
Stoping
Methods of ore-breaking; underhand stopes; overhan
d stopes; combined stope. Valuing ore in course of br
eaking.

CHAPTER XI.Methods of Supporting Excavation
Timbering; filling with waste; filling with broken ore; pill
ars of ore; artificial pillars; caving system.

CHAPTER XII.
Mechanical Equipment
Conditions bearing on mine equipment; winding applia
nces; haulage equipment in shafts; lateral undergroun
d transport; transport in stopes.

CHAPTER XIII.
Mechanical Equipment (Continued)
Drainage: controlling factors; volume and head of wat
er; flexibility; reliability; power conditions; mechanical
efficiency; capital outlay. Systems of drainage,—stea
m pumps, compressed-air pumps, electrical pumps, r
od-driven pumps, bailing; comparative value of variou
s systems.

CHAPTER XIV.
Mechanical Equipment (Concluded)
Machine drilling: power transmission; compressed air
vs. electricity; air drills; machine vs. hand drilling. Wor
kshops. Improvement in equipment. Page vii

CHAPTER XV.
Ratio of Output to the Mine
Determination of possible maximum; limiting factors; c
ost of equipment; life of the mine; mechanical inefficie
ncy of patchwork plant; overproduction of base metal;
security of investment.

CHAPTER XVI.
Administration
Labor efficiency; skill; intelligence; application coördin
ation; contract work; labor unions; real basis of wages
.

CHAPTER XVII.Administration (Continued)
Accounts and technical data and reports; working cos
ts; division of expenditure; inherent limitations in accur
acy of working costs; working cost sheets. General te
chnical data; labor, supplies, power, surveys, samplin
g, and assaying.

CHAPTER XVIII.
Administration (Concluded)
Administrative reports.

CHAPTER XIX.
The Amount of Risk in Mining Investments
Risk in valuation of mines; in mines as compared with
other commercial enterprises.

CHAPTER XX.
The Character, Training, and Obligations of the Minin
g Engineering Profession

Index
Page 1 PRINCIPLES OF MINING.
CHAPTER I.
Valuation of Copper, Gold, Lead, Silver, Tin, and Zinc
Lode Mines.
DETERMINATION OF AVERAGE METAL CONTENT;
SAMPLING, ASSAY PLANS, CALCULATIONS OF AV
ERAGES, PERCENTAGE OF ERRORS IN ESTIMAT
E FROM SAMPLING.
The following discussion is limited to in situ deposits of
copper, gold, lead, silver, tin, and zinc. The valuation
of alluvial deposits, iron, coal, and other mines is each
a special science to itself and cannot be adequately
discussed in common with the type of deposits
mentioned above.The value of a metal mine of the order under
discussion depends upon:—
1. The profit that may be won from ore exposed;
2. The prospective profit to be derived from
extension of the ore beyond exposures;
3. The effect of a higher or lower price of metal
(except in gold mines);
4. The efficiency of the management during
realization.
The first may be termed the positive value, and can be
approximately determined by sampling or test-
treatment runs. The second and the third may be
termed the speculative values, and are largely a
matter of judgment based on geological evidence and
the industrial outlook. The fourth is a question of
development, equipment, and engineering method
adapted to the prospects of the enterprise, together
with capable executive control of these works.
Page 2 It should be stated at the outset that it is
utterly impossible to accurately value any mine, owing
to the many speculative factors involved. The best that
can be done is to state that the value lies between
certain limits, and that various stages above the
minimum given represent various degrees of risk.
Further, it would be but stating truisms to those
engaged in valuing mines to repeat that, because of
the limited life of every mine, valuation of such
investments cannot be based upon the principle of
simple interest; nor that any investment is justified
without a consideration of the management to ensue.
Yet the ignorance of these essentials is so prevalent
among the public that they warrant repetition on every
available occasion.
To such an extent is the realization of profits indicated
from the other factors dependent upon the
subsequent management of the enterprise that the
author considers a review of underground engineering
and administration from an economic point of view an
essential to any essay upon the subject. While the
metallurgical treatment of ores is an essential factor inmine economics, it is considered that a detailed
discussion of the myriad of processes under
hypothetic conditions would lead too far afield.
Therefore the discussion is largely limited to
underground and administrative matters.
The valuation of mines arises not only from their
change of ownership, but from the necessity in sound
administration for a knowledge of some of the
fundamentals of valuation, such a