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By Steven Mitchell

BACKGROUND Homestake Mining Company began milling operations at the Bulldog Mountain Mine near Creede, Colorado in 1969. The Bulldog Mill, rated at 350 tpd, produces a bulk flotation condentrate assaying about 180 oz/T Ag and 20% Pb, from heads of about 16 oz/T Ag and 2% Pb. The circuit is straightforward with two-stage grinding to 1-5% plus 65 mesh, followed by rougher and cleaner flotation. Reagents used are Z-6, Z-11, Aerofloat 242 and Aero Promoter 404, with an Aerofroth 65-MIBC mixture for a frother. Additional information on the geology, mine and mill are available in references (1) and (2). A flow sheet for the mill and CIP plant together is attached as Figure 1. Final flotation tailings normally vary from 1.5 - 2.0 oz/T Ag. These tailings are cycloned to produce sand for underground backfill. After cycloning, the sands are repulped and given a final scavenger float. This sand scavenger recovers a small additional amount of silver which recycles back to the main flotation circuit. The tailings are recycloned and pumped to the mine or, if the mine cannot accept sand, to tailings. The majority of the silver in the flotation tailings exists in the fine fractions; cycloning upgrades the slimes and lowers the assay of the sand. The sand, after scavenging, typically assays 0.5 oz/T Ag, and the slimes assay about 3.0-3.5 oz/T Ag. From 1969 to 1976 all of the slime tailings and the sand tailings not used underground were impounded in a tailings pond located about

Jan 1, 1983

By M. K. Seguin

The study described in this paper is first centered on the determination of the physical properties (gravimetric, magnetic, electrical, and electromagnetic) o f metamorphosed iron ores of the Carol Lake-Labrador City District. Different geophysical surveys available in the Carol Lake-Wabush area were interpreted quantitatively and the dimensions, attitude, and tonnage of the ore bodies investigated were determined. A geophysical-statistical study was undertaken which permitted the determination of the grade of iron, magnetite, and, subsequently, specularite in the ore bodies. A discussion of the theory and logical progression of the study and the application of the results to actual geophysical data is presented. The conclusions, which are of real significance from the economic standpoint, may be predicted from the data obtained from geophysical surveys before any diamond drilling is undertaken. An integrated interpretation of this type is useful in planning future exploration work and selecting the most favorable geological structures. It also serves as a guide to minimize and determine tonnage drilling patterns. The general conclusion that a restricted range of residual gravity and magnetic anomalies are a key to exploration is valid. Indeed large depths to the top of deposits are absent since all the ore bodies are overturned synclinal structures with tops located close to the surface. Certain irregular geometries do occur but they are not common and the alignment of the iron ore bodies is sub parallel so that magnetic anomalies are evenly reduced in the earth's magnetic field vector.

Jan 1, 1975

By P. Barnes

(Read at the Wilkes-Barre Meeting, May, 1877.) IN vol. 33 of the Proceedings of the Institution of Civil Engineers, London (part 2, for 1870-71), may be found a statement of the cost of two blast furnaces, together with a somewhat detailed description. The attempt will be made in this note to restate these items of cost, so that the information may be rendered perhaps more accessible to our members than in its present place of record, and also in order that the items may be more intelligibly compared among themselves, or with similar items in other cases.

Jan 1, 1878

By Thomas A. Steven

Most mineralized areas in the central San Juan Mountains, Colorado, are associated with the youngest subsidence structures in a large volcanic cauldron complex that formed concurrently with eruption of the surrounding ash-flow field. Two local types have been recognized: (1) fissure-vein deposits along faults characterized by relatively late movement, and (2) hydrothermally altered and mineralized areas associated with postsubsidence Fisher Quartz Latite centers. The first type has provided most production in the past; the potential of the second type has yet to be adequately tested.

Jan 1, 1968

By W. T. Allan

RAW bituminous coal has been in general use as a blast-furnace fuel in Scotland for the last century, and although its use has now been largely abandoned and it has been replaced by coke in the majority of the few furnaces which are at, present in blast in this country, coal-smelted pig iron is not yet a thing of the past; it is still being produced and mar-keted in competition with the more cheaply smelted product of the coke-fired furnace. Various factors have influenced this change in practice; the once plentiful deposits of coal of a suitable nature for the blast furnace are now not so easily obtainable; native blackband and clayband ironstones which are easily smelted in the coal-fired blast furnace, although still far from being exhausted, are not available except at a. cost that is somewhat higher than that of imported ores, making them unattractive to the ironmaster that is compelled by circumstances to smelt his iron at the lowest possible cost. Within the last 15 years overproduction of synthetic nitrogen has led to progressive reductions in the price of sulphate of ammonia, the recovery of which together with the other by-products before that time materially assisted in reducing the working costs of the coal-fired furnace. Now the sale of the by-products recovered yields a diminished profit. When the cost of the product is the only consideration the small, slow-smelting, coal-fired blast furnace cannot compare with its large, modern, coke-fired competitor. Other `considerations do not by any means all support the same side of the argument. In the smelting of pig iron to be used in the manufacture of steel where the quality of the final product depends so largely upon the control of the conversion process and so much less upon the physical quality of the pig iron used, the physical properties of the pig iron do not exert any appreciable influence upon the quality of the steel produced, therefore the methods employed in the smelting of the pig iron matter but little so long as the requisite chemical composi-tion is reached. On the other hand, in ironfounding where the simple melting of the pig iron, which is the only treatment it receives before being cast into its final form, does little or nothing to modify its original charac-

Jan 1, 1937

By Fred C. Bond

AN improved method of measuring the surface area of a comminution product down to any desired particle size has been developed. The method is largely graphical, and requires relatively little calculation. It can be used with materials containing large amounts of clay, or excess fines of any kind. The surface area S is expressed in terms of square meters per 100 c.c. of solids. This expression is based upon volume rather than weight, and is considered to be more suitable for crushing and grinding problems, where the machines ordinarily are operated under constant volume conditions. It has the advantage that surface areas of different materials can be compared directly, even though their specific gravities may be unknown. The "specific surface" of a material, or the number of square centimeters of surface area per gram, is equal to 100S divided by the specific gravity. Particle diameters are expressed in microns, K being the diameter of the largest particle present and L the grind limit, or lower size limit of the particles formed directly by grinding. The value of K does not always coincide exactly with the diameters of the largest particles retained on the coarsest testing sieve, since the largest particles formed in crushing and grinding are often slabby, or have other irregular shapes. L has been chosen as 0.700 microns, or number 27.5 in the size number series, for reasons to be explained later. S is the total surface area of all particles larger than L microns in diameter. When a homogeneous comminution product is separated into fractions whose diameters bear a constant geometrical relationship p to each other, and the log per cent weight retained upon each size and passing the next larger size is plotted against the log diameter, a straight line results, which is called the distribution line, and which has a slope in called the distribution modulus. The distribution line can be extended to any desired limiting size, and the total surface area of all particles larger than that size can be calculated. The equation of the distributi0n line is [w = Cx" [I]] where w is the per cent weight retained on each successive sieve; x is the particle diameter; and C is the per cent weight retained on an opening of unit diameter.2 Theoretically, the distribution line can be extended to include infinitely small particles. When it is so extended, and the assumption is made that no fine particles are present other than those accounted for by the equation; the log per cent cumulative weight passing any series of sizes, plotted against the log diameter passed, will result in a straight line lying parallel to and above the plotted distribution line.

Jan 1, 1941

By Carle R. Hayward

ATHOUGH there are signs of improvement in the lead industry, conditions are still far from what we have been accustomed to call normal. There has been little to stim¬ulate research and those responsible for the finances of the companies have been inclined to discourage expenditures except where need was urgent or the prospect for immediate returns bright. In spite of this fact, improvements have been developed here and there which will be available as business conditions become adjusted. No publicity is allowed at present. The rising price of silver has had a tendency to increase the production of lead from argentiferous ores but the greatest interest continues to be in the secondary field. Practically all lead plants situated near large centers of population are treating scrap materials, particularly battery plates, the quantity of which is increasing with the improvement in automobile sales.

Jan 1, 1936

By B. F. Tillson

HAVING been asked to talk about recent devel-opments in mining equipment, I chose the sub-ject of small units of storage-battery locomo-tives which recently have been developed with the idea of motorizing transportation in the mines as far as possible, replacing the manual labor of hand-tramming. Metal mines are probably less advanced in this field than coal mines, where transportation of large ton-nages on any one level is quite common. Of course, metal mines, where large tonnages are handled on any one level, are as advanced as coal mines, and storage-battery locomotives for main haulages are used quite commonly in such metal mines, but the mines having levels at many intervals in the depth of the orebody, or a number of intermediate levels in which a consider-able amount of hand-tramming has to be done, and small metal mines in which the size of the orebody does not seem to warrant the initial capital expenditure for the driving of main haulage levels and installation of rock and ore chutes and raises for the delivery of the broken ore and rock to the cars have been at consider-able disadvantage in replacing manual labor by some mechanical means of transportation. Several years ago the field was canvassed among the manufacturers of electric-locomotive equipment and the conclusion was reached that the art had not been devel-oped to the advantage of metal miners who desire to replace small units of labor by locomotive equipment. The need for such small locomotives is all the more em-phasized by the development in the past few years of mechanical mucking-machines (loading equipment for filling the cars from muck piles on the level). Any me-chanical loader is a liability instead of an asset unless means are also provided for keeping the material away from the loading-machines. Therefore the transporta-tion system must be equal to the capacity of a loading-machine, otherwise the latter is idle such a large per-centage of its time as to prove an unprofitable invest-ment. So there is a need for portable, small haulage units to handle small mine cars in many metal mines, and, naturally, units are desired which can be so readily shifted from level to level as to facilitate their free use. Of course, in mines in which each level comes to the shaft it is not such a difficult problem, but many mines have a great many intermediate levels which must be approached through raises, timber slides or other small openings required to transfer ore and to get timber and other supplies to those levels.

Jan 5, 1927

By Leon Dominian

(Wilkes-Barre Meeting, June, 1911.) I. INTRODUCTION. THE lack of Aryan roots for the names of metals commonly known among the Aryan settlers of Asia Minor, as well as the later colonizers of Europe, indicates that these races were generally ignorant of the use of metals until they came into contact with Semitic peoples. Practically all mining-terms in current use among the earliest Greeks resemble very strongly their distinctly Semitic equivalents, which can be traced all the way in a broad belt beginning in Lower Mesopotamia, and extending westwardly to the Syrian shores of the Mediterranean. The Greek word " "metallon," for instance, used indiscriminately to designate mine or ore, probably came from the earlier Semitic equivalent, " matal." Again, the Greek words " chrysos " (gold) and " chalkos " (copper) seem to be descended from the Semitic forms " throats " and a chalak." It is a natural inference that primitive mining-methods were evolved by the dwellers in the mineralized areas of Asia Minor, from whom later Greek, Roman, and even North European miners obtained their first notions of the reduction of metallic ores, by virtue of a general westward migration of mining and metallurgy. Some traces of its passage through Turkish territory will be noted in this paper. While European Turkey can boast of one ancient gold-field, the Asiatic dominions of the Sultan may lay claim to at least two well-defined and widely-separated gold-producing districts. These three regions may be distinguished as the Thracian, the Pontic, and the Anatolian gold-fields. II. TURKEY IN EUROPE. . The Thracian Gold-Field. The most conspicuous topographic feature of the lowland between Constantinople and Salonica is the uplifted Archaean

Nov 1, 1911

By M. C. Udy, P. C. Rosenthal

THE use of minute boron additions to steel has been given considerable attention in recent years. Comparisons made between boron-free and boron-containing heats of otherwise identical analysis have indicated, beyond a doubt, the potent effect of boron for increasing hardenability. The actual hardenability increase has been expressed as a multiplying factor, or in terms of the percentage of other alloying elements boron might replace, The present study presents the results of a systematic survey of. the use of boron as an addition to two types of alloyed steels and as a replacement for various percentages of molybdenum in these steels, Both cast and wrought steels of the two basic compositions were prepared. Molybdenum, because of its scarcity at the time the investigation was started, was selected as the element to be replaced by boron. Attention was also given to the effects of boron on other properties of the steels, particularly their notched-bar toughness, to investigate other advantages or limitations of this element as an alloy addition. EXPERIMENTAL WORK Steels Investigated The two basic compositions used in this survey of boron as a replacement for molybdenum are given in Table I. The cast steels were higher than the wrought steels in silicon content to improve the casting quality. [ ] Each of these base steels, both cast and wrought, was made with molybdenum contents of o, 0.10, 0.20, 0.30, or 0.40 per cent, the total comprising 20 steels. In addition, each of these 20 compositions . was prepared with boron additions in amounts of 0.0015, 0.003, and o,006 per cent as ferroboron; and in amounts of 0.002 and 0.005 per cent as two com¬mercial intensifier alloys, designated alloys A and B. The boron-treated steels totaled 100, and the entire series 120, Test Procedure Each steel was melted as an individual heat in a 50-lb., magnesia-lined induction furnace. Ingot iron scrap or mixtures of ingot iron and steel scrap were used for melting stock. Deoxidation was carried out in the furnace with o.10 per cent aluminum. The aluminum addition was

Jan 1, 1946

By Kenneth N. Weaver

Portland cement can be made from relatively abundant industrial minerals and rocks, and this may explain why cement producers placed little emphasis on geology during the early days of the industry. After World War II, however, the industry began to recognize the need for geological exploration, and some of the larger companies began to build a permanent geological staff. This development had its roots in the following factors: Rapid expansion of the industry; closing of many cement plants due to inadequate raw materials; necessity for upgrading the quality of portland cement; and the increasingly large capital investment required to build new cement plants, which in turn, required a higher degree of accuracy in reserve calculations. Whereas the geologist's function during the active expansion of capacity was primarily in exploration, one of his major functions today is the development of existing reserves.

Jan 1, 1965

By Willard P. Ward

Having been engaged during the past year in the manufacture of ferro-manganese in a blast furnace, I have imagined that some further information on this subject might be of interest to that large number of members of the Institute who are engaged in the iron and steel industries. The great question of the economical production of good steel, ingot metal, or homogeneous iron (we scarcely know now what to call it) from good materials, and at reasonable prices, has, thanks to the intelligence and energy of a few American engineers, been successfully solved in this country. Nearly all first-class railroads, and many that would not rank so high, have adopted the Bessemer rail. Martin boiler-plates are rapidly gaining ground, in competition with

By H. F. Perkins

CORROSION as an economic problem is growing rapidly in importance not only because it entails a replacement of corroded parts, but because it interrupts operation and causes hazards of damage and injury through failures of corroded equipment. Nearly all industries are interested in this subject. This paper, although concerned chiefly with corrosion in a complete refinery on the sea coast, discusses many of the various forms of chemical decomposition, most of which are found universally. The petroleum refining industry, in the writer's opinion, is seriously afflicted by the presence of sulfur in nearly all crude oils. The complete removal of sulfur from the crude as it enters the plant would cause such a relief from corrosion that this problem for research would seem to demand active attention. Next to sulfur the most troublesome corrosive agent is the saltmagnesium chloride, found in the water associated with crude oil, the last traces of which are so difficult to remove. This is much less serious, however, than the sulfur. Refinery corrosion can be tabulated as follows: Causes of Corrosion and Places of Attack in a Refinery CORROSIVE ELEMENTS MATERIAL ATTACKED Air: Pipe lines Moisture Tanks COQ Electric fixtures Sulfur gases Still towers Chlorine Condenser boxes Other acid-forming gases Ladders and stairs Smoke stacks Steel buildings All exposed metal Water: Alkali Fire lines and hydrants Acids Cooling water lines Air Condensers and coolers Other dissolved gases Boiler tubes Steam Steam pipes and valves Turbines Oil Sulfur compounds Tanks, pipes, valves, stills, towers MgCl2-Hydrochloric acid Condensers Air contamination

Jan 12, 1926

By L. L. Newman

As soon as the Congress recognized the alarming rate at which our domestic oil resources were being depleted during the war, it took action to step up the rate of research and development which the Bureau of Mines had been conducting for several years on the production of synthetic liquid fuels from coals. Under Public Law 290, approved April 5, 1944, funds were authorized for the Bureau to proceed with research, development, design and construction of demonstration plants for the hydrogenation of coal, the synthesis of oil from carbon monoxide and hydrogen, and the distillation of oil from shale. During the latter part of 1944, when it became evident that the collapse of Germany was near, a Technical Oil Mission was organized to study the Ger- man techniques of synthetic oil production. Since the cost of hydrogen or synthesis gas is one of the major factors of expense in the operation of hydrogenation or synthesis gas processes, the Bureau of Mines considered it of prime importance to include on the mission gas engineers whose instructions were to examine closely the methods employed by the Germans in solving the problem of providing low- cost hydrogen or synthesis gas for their very extensive operations on synthetic liquid fuels. The Solid Fuels Mission and the Utilities Mission, as well as the Army and Navy Missions, also included teams for the study of German gas production. Although their objectives naturally differed from those of the Technical Oil Mission and from each other, it was recognized that there was considerable overlapping of their fields of investigation. Duplication of effort, however, was largely avoided through the close cooperation between the group leaders of these missions. For example, although I went to Europe as a member of the Technical Oil Mission, my first German assignment was actually made by Dr. Harry F. Yancey, leader of the Solid Fuels Mission- to investigate the brown-coal gasification methods in central Germany. The art of gasification in the United States and England, and to a large extent in the proximity of the coking-coal regions of Germany and the rest of continental Europe, depends essentially on two stages of operation; namely, carbonization and intermittent water-gas generation. As far as the United States is concerned, complete gasification in a single stage of operation is rarely practiced, except in gas-producer operations where the product is a relatively lean gas consumed close to the point of manufacture, and for water-gas production with anthracite as a generator fuel. Complete gasification of bituminous coal has been the subject of numerous investigations. Many relatively simple modifications of the water-gas generator have been tried to permit the direct gasification of low-cost bituminous coal instead of high- cost coke and anthracite for the production of water gas. Although varying degrees of success have been achieved and the water gas produced generally has been higher in calorific value, in only a few isolated in- stances has there been any sustained use of bituminous coal for water-gas production for public utility uses after the shortages of anthracite and coke have been lessened.

Jan 1, 1946

CONTENTS PAGE INTRODUCTION AND ACKNOWLEDGMENTS. By George M. Fowler 2 Question 1-Is Structural Deformation of Some Character Always Necessary for the Migration of Mineralizing Solutions, Especially in Limestone or Other Dense Rock? DISCUSSION by: A. M. Bateman 10 S. F. Kelly 15 C. H. Behre, Jr 8, 13 G. B. Langford 13 T. M. Broderick 11 H. E. McKinstry 6 R. H. Clarke 13 D. H. McLaughlin 8 J. D. Forrester for M. H. Gidel . . . 4 W. H. Newhouse 13 G. M. Fowler 2, 6, 11 R. H. Sales 6 L. C. Graton 11 Edward Sampson 12 R. D. Hoffman 10 J. S. Stevenson 7 I. B. Joralemon 11 L. B. Wright 2 Question 2-What Are Some of the Chemical and Physical Characteristics in Cer¬tain Beds within a Limestone Formation that Determine Their Favorable or Unfavorable Aspects as Reservoirs for Ore and Other Introduced Minerals? DISCUSSION by: G. W. Bain 17 G. M. Fowler 21 C. H. Behre, Jr 21 L. C. Graton 18 J. S. Brown 16 G. F. Loughlin 18 E. L. Bruce 19 R. H. Sales 19 R. H. Clarke 20 A. K. Snelgrove 20 Question 3-Are There Any Criteria by Which One Can Determine When Min¬ing Operations Have Reached the Roots of an Ore Deposit? DISCUSSION by: J. M. Boutwell 29 G. B. Langford 29 T. M. Broderick 28 G. F. Loughlin 25 E. Y. Dougherty 27 R. H. Sales 24 G. M. Fowler 22 F. A. Thomson 26 I. B. Joralemon 22 Edward Wisser 30 General S. F. Kelly 35 References 36

Jan 1, 1940

By Michael J. Messel

OF the various minerals that occur in fibrous form known as asbestos, chrysotile is the variety most in demand for commercial uses, and, last year, over 683,000 tons of the various grades were produced in Canada and United States, exclusive of African and Russian production, which figures are uncertain. Production has not been able to keep up with the increased demand, and an acute shortage exists. Canada, Russia, and Africa are still the most important producers. However, Russia consumes most of its production at home and exports very little. The United States consumes over 60 pct of the total production and produces only about 4 pct of the total from deposits in Vermont and small quantities from Arizona. This paper will review mainly, some of the more recent developments concerned with the extraction and processing of this fibrous mineral for various industrial uses, such as textiles, insulation, building materials and brake linings.

Jan 1, 1949

By Henry Mackay

THE interesting paper recently submitted by Messrs. Tobelmann and Potter' shows that chemical problems have developed which are of great interest in this new and important branch of metallurgy. Those who realize what a process of this kind really involves will agree that it deserves a better name than "leaching process." The word leaching conveys the idea that the copper is simply leached out of the ore with acid and then precipitated on iron; the chemistry of such a process would be of little interest. As, however, during the first year's operation of this plant 24,400,532 lb. (11,067,837 kg.) or about two-thirds of the produce, was electrolytic copper, while 7,992,033 lb., or about one-third, was cement copper, it would seem more appropriate to term the process electrochemical. It further appears, from the particulars given, that efforts have been made to have the entire production in the form of electrolytic copper. -This could be done if the chemistry of the problem were kept in balance, so that it would not be necessary to discard any solutions that carried copper and acid of commercial value. A process, such as that under consideration, in which the copper is precipitated from solution by electrolysis, the solvent being at the same time regenerated, is one that requires special chemical and electrochemical knowledge and experience if all the -copper in solution that has been extracted from the ore is to be successfully and economically produced as electrolytic copper. The object of this paper is to discuss, from the practical and theoretical standpoints, the chemical and electrochemical problems involved in the working of a process of this kind, and' which must be solved to keep it in chemical and electrochemical equilibrium. In such a process, if the chemical balance is maintained, a solution can be used alternately as a

Jan 9, 1919

By Thos Egleston

The sands of Snake River, Idaho, have long been known to contain gold. They were worked by some of the first prospectors who came to Idaho, and on the banks still stand the ruins of camps abandoned for years. There are almost always prospectors searching for gold during the season of low water, and it is not an infrequent thing to find a miner of the old type actually panning the sand, or the prospect-hole which he has just left. There is more or less mystery about these miners and their methods of finding the spots where they work. They are always subjects of much speculation to the ordinary traveller. The rich discoveries are, for the best of reasons, concealed until the claims can be taken up. It is difficult to find a place where there are no prospects, but the " colors " are so very fine that they do not offer much inducement to enterprise. The California miner usually values a color at from 5 to 10 cents, often the latter; while on Snake River it would take 100 colors, or even more, to make that amount.

Jan 1, 1890

C. W. MERRILL*—Mr. Hughes' paper not only is very well presented but is most timely in that it covers a subject of vital interest to the United States. Tin is one of the strategic metals which has not been found here in appreciable quantities. The total United States tin output since the first recorded production over 100 years ago would not supply current consumption for a fortnight. On the consumption side, tin is extremely important in national defense because of its use in tin plate which, in the form of tin cans, makes it possible to feed properly the armies that the United States recruits from its civilian population in emergencies. Moreover, the internal combustion engines so important in powering tanks, planes, and other war machines, require large quantities of tin alloys for bearings and for soldering. These considerations, along with the fact that Malaya, historically, has been the leading source of tin to the United States, make the kind of information that Mr. Hughes has presented so ably. a matter of vital interest. Your Chairman, Mr. Romanowitz, in his introduction, referred to the fact that I had been a member of the United States delegations to the three meetings of the International Tin Study Group. Some comments on the Group's objectives and deliberations may be of interest. When it appeared that the International Tin Committee, the prewar producer's cartel, might soon revive its operations and extend its control agreement beyond the expiration date of Dec. 31, 1946, the United States Government became interested in some kind of an international trade organization concerned with tin which would give the consumers' interest equal representation with the producers' interests. An international meeting was called in London in October 1946 to consider this problem. I did not attend that meeting hut the result of the meeting was the organization of the International 'Tin Study Group which

Jan 1, 1950

By F. C. Wagner, E. P. Klier, D. E. Nulk

The presence or absence of plastic strain at a cleavarage surface is a question of much importance, and upon its answer depends future possible theoretical work. To investigate this question back-reflectinn X ray patterns were obained on the cleavage facets of ferrite grains. The test set-up consisting of FeK colli- mated radiation, single grain material and stationary cassette and specimen will not lead to a diffraction pattern, in general, but is an ideal arrangement for the exami-nation of surface effects. A pattern taken on hydrogen purified

Jan 1, 1949