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By Henry M. Howe

This paper gives the results of an investigation of the beha vior of the argentiferous cobalt-nickel arsenides of Temiskam-ing, Ontario, in roasting, made in the metallurgical laboratories of the School of Mines of Columbia University in the City of New York. The ore was kindly given by the owners of the La Rose and Trethewey properties at Cobalt, Ontario, and Mr E. J. Hall, Tutor in Assaying in Columbia University, has helped us much. I. Object of the Investigation. The object of the investigation was to learn: 1. The temperature at which the arsenic is most rapidly expelled ; 2. The thoroughness with which it is expelled by prolonged roasting at this temperature; 3. The effect of adding charcoal (a) near the end of the roast and (b) at. the beginning of the roast. II. Nature of the ORe. The important ores mined in the Temiskaming deposits are: native silver—with small amounts of dyscrasite (Ag,Sb), ar-gentite (Ag,S), pyrargyrite (Ag,SbS,)—smaltite (CoAs,), chlo-anthite (NiAs,) and niccolite (NiAs). Mispickel (FeAsS) and cobaltite (CoAsS) also occur in smaller quantities. The average composition of the ore shipped from this district for the first six months of 1905 was: silver, from 4.1 to 4.8 per cent.; cobalt, from 6.9 to 8.2 per cent.; nickel, from 3 to 4.7 per cent.; and arsenic, from 30.9 to 34.6 per cent. The ore which we treated consists chiefly of smaltite. In our 1aboratory-work

Jan 1, 1908

By William A. Vogely

Mining employment in the United States declined from 986,000 employees in 1948 to about 600,000 employees today. This has occurred even though the Index of Physical Volume of Mineral Production (1957-59=100) has increased from 88 to 111 and the value of mineral production measured in constant(1957-59) dollars has increased from $14.7 billion to approximately $19.3 billion. Average unit mine value has increased 24% as compared with a 34% increase in prices in general. Apparent consumption has increased more than domestic production, indicating an increased dependence on imports. The mineral economy presents a complex pattern of development factors in the post-war period. This article presents a technique by which the various forces that have been acting on the market for a mineral commodity may be sorted out and by which the extent of the impact of technological change in use as well as the technological change in production can be measured. If one is interested in delineating fully and completely the impact of technological change upon the mining industries, it is not sufficient to describe the increase in productivity reflected by the above employment and production figures. What is reflected there is only the effect of technological change in the production function of the commodities under concern. These effects are obviously very substantial and have major implications for labor, capital and supplying industries. However, they are not the only effects of technological change and, in fact, may be relatively minor when the impact which arises because of changing technology in the using or consuming industries is considered.

Jan 4, 1965

By Ionel I. Gardescu

During the summer of 1930 the average daily oil production of Rumania registered a new peak at 128,000 bbl. per day. The estimated potential production as of September, 1930, was as high as 235,000 bbl. per day. During the latter part of the year, by mutual agreement, the operators decided to curtail their output to about 100,000 bbl., which brought the average for the year to 116,600 bbl. The total production for 1930 was 41,572,000 bbl. (last month estimated) as compared with 35,757,000 bbl. for 1929, or an increase of 16.3 per cent. over last year's production. The production for the last 10 years is given in Table 1. The curtailment of production was prorated per company, based on its total estimated potential production as of September, 1930, and not per field. As a consequence, at present there is little development of protected or slightly productive areas; viz., Arbanasi, with an average production of 1750 bbl. per day, dropped to less than one-third after curtailment came into effect. Moreni, with an average production of 92,000 bbl. per day, while producing 58 per cent. of the country's total output in 1929, went to 67 per cent. at the beginning of 1930 and to 75.2 per cent, towards the end of the year. The modified Mining Law of 1929 is still in effect. This law withdraws the restrictions set on foreign capital by the law of 1924. As a consequence a large percentage of proven state land was alloted through competitive bidding to foreign companies. The Romano-Americana (Standard of New Jersey) acquired several leases in the Boldesti and

Jan 1, 1931

By A. M. Ross

DEURING the past year the uranium milling industry has seen the installation and initial operation of solvent extraction circuits in the Climax Uranium Co. mill at Grand Junction, Colo.; the Kerr-McGee Oil Industries mill at Shiprock, N. M.; and the AEC pilot plant at Grand Junction, operated by National Lead Co. Inc. The Vitro Uranium Co. mill in Salt Lake City is converting to solvent extraction, and the new Union Carbide Nuclear Co. mill to be constructed at Rifle, Colo., will also employ this method. Solvent extraction circuits will be incorporated in two mills now under construction -the Texas Zinc Minerals Co. mill at Mexican Hat, Utah, and the Gunnison Mining Co. mill at Gunnison, Colo. In Canada the expansion of the Eldorado mill at Port Radium includes installation of a solvent extraction circuit. Solvent Extraction Process: In simplest terms, the organic solvent is mixed with leach liquor and then the organic and aqueous phases are allowed to separate. By this contact the solvent selectively extracts uranium from the liquor, leaving a raffinate, or barren leach liquor, which may be discarded. The pregnant solvent is stripped of its uranium by con- tact with a stripping solution, such as aqueous sodium carbonate, which has a greater affinity for uranium than the solvent does. The barren solvent from the stripping step is available for further leach liquor extraction, and the pregnant stripping solution, which usually contains 30 to 60 g U3O8 per liter, is ready for precipitation of a final product, or uranium concentrate.

Jan 9, 1957

By Joseph L. Gillson

YOUR speaker has long sought an opportunity to review the many differences between the subject matter called economic geology and the duties of a practicing economic geologist. As the subject was taught in my student days, professors teaching courses in economic geology paid little attention to what we now call industrial minerals. Certainly they were not concerned with problems involving production and marketing, but only with the origin of such mineral deposits as the Stassfurt potash deposits; with other evaporites, such as salt, gypsum, and Chilean nitrate; with the possible modes of formation of sulfur in salt domes; and the causes of asbestiform mineralization. Of course, much time and thought was given to the mineral identification and sequence of deposition of the minerals in pegmatites. The fact that such deposits actually produced commercial feldspar, mica, beryl, and lithium minerals for sale in industry was of minor importance. These observations lead us to pause to inquire, perhaps facetiously, what is and what is not to be included in the science of economic geology?

Jan 5, 1957

By Halbert Powers Gillette

FROM the known laws of physical chemistry I believe it can be shown that progressive mass movement of water solutions in channels has seldom been the means of ore-concentration in veins. It is my purpose in this paper to show that the force known as “osmosis” has been the principal factor in ore-formation. Convection-currents have doubtless supplemented osmosis, and the two working together have been the agencies that have gathered the scattered particles of rare minerals into the larger masses which are called ore. Osmosis is commonly thought of as a vague, feeble force that causes slow diffusion of dissolving matter through the solvent. That it is a measurable force, often of great intensity, few know, except those who are familiar with the laws of modern physical chemistry. Therefore, I may be pardoned for going briefly into the elementary mathematics of osmotic pressure and of convection-currents. The velocity of water moving through any channel is given by the Chézy formula: (1) v = c [/rs], in which r is the hydraulic mean radius; s, the slope of the channel in which gravity is the sole propulsive force; and c, the coefficient of roughness of the sides of the channel. From this formula it is evident that the smaller the channel, the smaller the velocity of water under a constant head. In rock-crevices, therefore, where the head is constant, water moves much more slowly than in large fissures, and in moving through sand or porous rock it is to an even greater degree retarded. Hence, if a mass of water-saturated sand be heated, the finer the sand-grains, the more slowly will the temperature rise at parts remote from the source of heat. Conversely, cooling is retarded the smaller the interstices or channels through which the convection-currents move. The importance of this

Jan 1, 1913

By Frederic P. Dewey

Having shown1 the difficulty of assaying so-called cyanide bullion and the extreme variations often found in the results, an investigation was undertaken to discover, if possible, the causes of these variations by a series of tests upon the specific action of various metals during cupellation. Zinc.—In order to test the effect of zinc, 48 assays were made in sets of 6, 2 rows of 3. The charge for the middle cupels consisted of 500+ mg. Au, 1,125 mg. Ag, 10 mg. Cu. To the end cupels 50, 75, 100 and 125 mg. Zn were added, and a set of each proportion was cupelled with 4 and 8 grams Pb. The cupels were assayed and showed the following gold contents in milligrams, the figures being arranged as the cupels stood in the muffle: In many instances the zinc does not appear to affect the cupel gold, but various exceptions are apparent, generally in the cupels in the back row. With 100 and 125 mg. Zn, in some cases the Zn burned with its characteristic flame' before it could alloy with the other metals. Also, less fusible oxidized lumps were observed during the cupellation and some cupels showed a scum. In order to lessen the premature burning out of the Zn, an alloy of 2 parts Ag to 1 part Zn was used. A uniform charge of 500+ mg. Au,

Jan 1, 1918

By R. A. Wyman

KYANITE schists in the Sudbury area have been generally described by Haw,' who has also given particuLar information on preliminary treatment of three large samples from Dryden township, Ontario.' Kyanite, garnet, biotite, quartz, and feldspar comprise the main ingredients of this ore. Kyanite is the valuable mineral. About 5½ tons of —35 +200 mesh product, made by dry rod milling, screening, and separation on the Exolon magnetic separator, were available for treatment by flotation. Magnetic separation had effectively reduced garnet and biotite so that flotation feed consisted essentially of kyanite, quartz, and feldspar, the kyanite content averaging 32 pct and representing about 86 pct of the kyanite in the original ore. Earlier work on kyanite at the Mines Branch, Ottawa, s-c employed an acid circuit, but to avoid production difficulties in the use of acids and at the same time take advantage of the fact that industrial minerals respond somewhat to soap flotation, it was decided first to investigate the higher pH levels. Exploratory tests using —65 +200 mesh feed ended with production of 96.6 pct kyanite concentrate rep-

Jan 1, 1959

The 48th convention of the International Union of Mine, Mill and Smelter Workers, held in New York City recently, saw delegates vote funds for a new organizational drive expected to begin immediately. John Clark, union president, told members in his keynote speech, that the union would be in a better position to make demands if it extended its membership to all phases of the nonferrous -industry. He told the 250 delegates that union leaders have already laid extensive groundwork for the campaign. Clark said: "I am proposing here that we concentrate on organizing during this coming year. I am proposing that we throw a heavy amount of re sources in organizing. That means financial resources as well as re- sources of staff ."

Jan 1, 1952

Jan 1, 1927

By M. A. Grossman

Jan 1, 1947

By M. A. Grossman

Jan 1, 1947

By E. G. Leonardon, D. C. McCann

The search for oil has required, and without a doubt supplies, a tremendous amount of information on the structure, composition, physical properties, and history of sedimentary rocks. The earliest and most complete source of knowledge is the sample or core of the rock itself, the uses of which are well known. The purpose of this paper is primarily to discuss a new method for obtaining these cores, and to illustrate its use in connection with electrical logs. Most cores have been obtained through a special adaptation of rotary drilling, and the results have been remarkably good, considering the mechanical problems involved. Unfortunately, because of the time and expense, this method cannot be used for the entire length of the drill hole. Even though ingenious contrivances have been evolved in order to reduce the time spent in round trips, such as wire-line coring equipment, mechanical coring still remains too expensive to be carried out continuously. In practice, therefore, one is finally compelled to estimate the probable depths of the more interesting horizons and, allowing a wide margin of safety, to core through those sections only. It is true also that interesting results have been obtained by examining the cuttings brought to the surface by the mud circulated in the well during the process of drilling. Be that as it may, the inescapable fact remains that key horizons may be passed inadvertently, for one reason or another, while the drilling operations are being performed. The only continuous record of the formations encountered is that furnished by electrical surveys. Obviously, it would be desirable to make the electrical survey first and to take the samples from the wall of the hole according to the indications on the electrical log. In this way, it would be possible to core only the exact sections desired, eliminating the otherwise inevitable estimates as to the point at which to start coring, and thereby reducing to a minimum this expensive operation. At the same time this method would provide a maximum of useful samples. A device for taking samples of the formation from the walls of a hole therefore offers the possibility of recovering cores from zones otherwise lost as a source of this type of information. Furthermore, by coring

Jan 1, 1939

By H. H. Stoek

A study of Americarf coal-mine practice shows two of its distinctive features to be: A greater number of accidents per thousand employees than in any of the other leading coal-producing countries; a much greater percentage of the coal lost than in any of the other leading coal-producing countries. Although our subject is mainly concerned with the second feature, any consideration of mining methods should include safety, efficiency, and economy or costs. If the argument could be offered that our wasteful mining was necessary on account of safety, and that it is carried out with less loss of life than in other countries, the plea for conservation of coal could not he so strongly urged. But when we are wasteful of both life and property, the subject merits more: consideration than it has received. Some coal operators will doubtless say that the unit of accidents should be the number per million tons produced rather than per thousand employees, for by adopting this unit America probably stands in the lead rather than the lowest among the countries. However, vital statistics are not usually so expressed by other governments, by life and accident insurance companies, or in other industries, and it is merely begging the question and attempting to bolster up a bad condition to adopt a peculiar unit for the statement of our accidents. For many years the statement was made by various agencies, and was unchallenged, that "For every ton of bituminous coal mined in the United States a ton had been lost in the way of pillars left in the mines." This statement was undoubtedly true for many years, and although in the past decade some progress has been made toward obtaining a higher extraction, and in some districts very decided progress, the loss is still great; and, although no exact data can be given, it is probable that for the United States as a whole at least one ton is lost for every two mined.

Jan 1, 1923

By Donald L. Katz, Marshall B. Standing

Density data are reported on 16 saturated hydrocarbon vapors at Pressures ranging from 1000 to 8220 Ib. per sq. in. and at temperatures ranging from 35° to 250°F. These data have been used to extend the compressibility-factor chart for natural gases up to 10,000 lb. per sq. in. The relatively large quantity of high-boiling constituents present in high-pressure vapors in equilibrium with crude oils makes it necessary to include in the analysis of the gas the molecular weight, density, and possibly boiling range of the heptanes and heavier fraction. Relationships have been presented by which the density of gases may be obtained directly from the temperature, pressure, and gas gravity provided the gases have a common source or are similar in composition. Introduction The densities of natural gases are necessary in many engineering in in petroleum production and utilization, Gas reserves, changes in reservoir pressure, gradients in gas wells, metering of gases, pipeline flow, and compression of gases are typical problems requiring the density of the gas. A decade ago, engineering computations used ideal gas laws with deviations up to 500 Ib. per sq. in.4 Recent discoveries of pools having Pressures UP to 7500 lb. Per sq. in., and installation of pressure-maintenance and recycling plants, have increased the need for data On gas density at high pressures. Methods of Computation The accepted method of computing the density or specific volume of natural gases is the use of the ideal gas law corrected by a compressibility factor. The method proposed by Kay7 of correlating compressibility factors for gaseous mixtures on pseudocritical properties5 appears to be satisfactory for natural gases.2 The meth-me-compressibility factor has been shown to deviate systematically from the behavior of natural gases2 and a chart giving these corrected factors is available. A method of computing specific volume of gaseous mixtures from partial molal volumes has been reported by sage and Lacey.8 Complete data for the computation are not yet available for all hydrocarbon gases. Most- of the reported data on gas densities have been in the single-phase region removed from the dew point or saturation condition. Since most gases in the reservoir Or while on contact with liquid '''ring flow are saturated, the determination of densities under conditions of saturation is particularly important. Although there is no reason to believe that the saturated gases differ in behavior from those consider. ably removed from their dew points, the usual experimental determinations find difficulty on approaching the dew-point conditions, This paper reports the density of I6 saturated gases in equilibrium with crude oils. The relationships developed to compute the density of gases to high pressure' have been modified and enlarged. A simpli-fied method of obtaining gas density is presented in the Form of charts, which apply for specific groups of gases.

Jan 1, 1942

By John E. Conley, John A. Ruppert

LIGHTWEIGHT aggregates have been in use for many years in the United States but are now receiving more and more attention by manufacturers and users of concrete shapes. These shapes comprise building blocks, special forms, such as door sills, lintels, floor slabs, and beams. Lightweight aggregate also is adapted for monolithic construction. The increased building activity since termination of the war, together with the widespread shortage of cinders resulting from a general trend toward the use of oil and pulverized-coal fuels, has aggravated the situation. In some localities? new producers of lightweight aggregates have been stimulated to increased efforts to supply the demand. In addition, various estab- lishments of the United States Government have recently given attention to this problem. The National Bureau of Standards, in the Commerce Department, and the Bureau of Reclamation, in the Interior Department, have completed a series of tests on concretes made from some of the available commercial aggregates in order to evaluate their qualities. The tests have been made to focus attention on the desirable properties of good aggregates. This work was done at the request of the Technical Office of the National Housing Agency and Housing and Home Finance Agency. Some time previously, the former office had conducted a survey of the locations where lightweight aggregates are produced.' A study of this information discloses that the producing centers are widespread and that certain areas, notably the region east of the Mississippi River and especially the southeastern states in the sections along the Atlantic Coast, have only a limited number of such plants. The situation has been alleviated to some extent with new plants having been erected near Richmond, Va., and Lansford, Pa. Experiment Stations of the Federal Bureau of Mines at Tuscaloosa, Ala., Norris, Tenn., and College Park, Md., have investigated types and sources of potential raw materials such as clays, shales, and slates, as well as methods and procedures for utilizing these materials for their conversion into aggregates, and have published the data as a Bureau of Mines report.' Structural Uses of Lightweight Aggregates: Production of masonry blocks in the United States has averaged close to a billion units a year for the past three years, and of these it is estimated that more than 40 pct consisted of the lightweight type. It is anticipated that the future will witness an increase in this percentage in view of the superior insulating properties, decrease in dead weight, and ease of handling, transporting, and laying units of this type. Lightweight aggregates are used extensively in multistoried buildings in which the weight of the walls and floors is carried by a structural steel framework. The substitution of a lightweight concrete for normal concrete in a building of this type has brought about in many instances some or all of the following advantages:

Jan 1, 1951

By P. R. Kalischer

In the production of alloys by powder metallurgical processes it is often necessary or desirable to include one or more cornponents that tend to form very stable oxides. Included in this group of metals are aluminum, manganese, magnesium, silicon, and a few others. In many cases it is not necessary for the sintered compact to have full density and the other physical characteristics of a cast alloy and in that event no undue precautions need be taken. If, however, it is required that the sintered part be entirely homogeneous, and have maximum density and physical properties, some method must be found to reduce the surface films of oxide, which are always present on the metals, and for the metals mentioned above this is always extremely difficult, if not impossible. since the production of high-density alloys is of particular interest to powder metallurgists, some experiments were undertaken to devise methods of reducing the refractory oxides. For this work, alloys of iron, nickel, and aluminum were chosen because aluminum oxide is one of the most stable oxides and because these alloys in the right compositions form excellent permanent magnets. All of the pertinent properties of the magnets could be accurately and delicately measured by density measuremerits and magnetic tests of sufficient scope to give a complete demagnetization curve. From such a curve the maximum coercive force, residual magnetism, and energy products could be obtained and compared with the same properties for a cast material. Any lack of homogeneity, density, or solid diffusion would be immediately apparent as a decrease in the magnetic properties. Nature and Removal of Surface Barriers The early work of the present investigation was based upon published processes.* In the published information it was claimed that by intimately mixing iron, nickel, and iron-aluminum alloy (50 Per cent Fe, So Per cent Al) powders, compressing such a mixture into the desired shape and size, and then sintering (heating to a temperature below the melting point of the component metals) in hydrogen at 1200°C. or higher, a sound, homogeneous article could be made having the desired physical size, shape, and strength, and good magnetic characteristics. However. this early work showed clearly that something in the powder compress was inhibiting diffusion and the process was almost entirely unworkable. In the initial phase of the investigation samples of iron powder, nickel powder, and iron-aluminum alloy powder were pressed into separate bars and sintered in hydrogen. Both the iron and nickel powders sintered

Jan 1, 1941

By W. M. Mobley

The coal industry in Alabama, centered in Birmingham, has pioneered coal-bene-ficiation practice in the United States. The nature of the coal seams and mining methods employed have necessitated use of equipment and methods best adapted to the local conditions. Although all of the 30 or more coal seams now being mined in the state receive beneficiation, only the three most important producers of coking coals, the Pratt, Mary Lee and Black Creek, are discussed in detail. Nature of the seams, washability characteristics and equipment used are given as examples of the extent of work and progress in this field. The coal seams in Alabama are relatively thin and pitching, making mining difficult and expensive. Most of them are characterized by thin partings of rock or shale in the seam itself, as well as laminations of bone and rash. Mechanical mining methods have increased the occlusions from roof and floor to such an extent that nearly all the coal mined in the state must receive some treatment before it can be put on the market. During the year ending Sept. 30, 1943,' 18,129,792 tons of coal were mined in the state and 14,364,177 tons, or 79.2 per cent, received treatment. Excluding from the total the 1,223,014 tons produced by small wagon mines and the hand-picked lump coal, the amount re- ceiving beneficiation would be more than 90.00 per cent. This is, by far, greater than in any other coal-producing state. The earliest record of coal beneficiation in Alabama was the installation in 1890 of an experimental Lurig washer by Alexander Cunningham, for the Sloss Iron and Steel Co. at its blast furnace in Birmingham.2 In 1894 the Jeffrey Manufacturing Co. introduced the English Robinson washer, a combination of a hydraulic classifier and centrifugal machine. Erskine Ramsay, who has contributed so much to the coal industry, saw its possibilities as well as its mechanical defects and soon had his inventive mind at work. He added a sludge tank of his own design, and many Robinson-Ramsay washers were installed in Alabama and other states. The Stewart jig appeared in 1900, followed by the Montgomery jig in 1910 and both have found extensive use. Increased interest in this field led to new designs, such as the American, Elmore, Burke and Faust. The first Baum-type Norton jig was operated in 1930 and within the last five years six large installations of this type have been made by the McNally-Pitts-burg, Jeffrey and Link-Belt Companies. Wet-washing tables were introduced in 1922 but not extensively used until recently. The two most popular types are the Deister-Overstrom and Deister Plat-O. The coal-cleaning equipment used in Alabama has been relatively simple, yet efficient, but as the amount of impurities in the raw coal has been increased by mechanical mining and labor costs have become higher, much interest has been shown in sand cones, froth flotation and

Jan 1, 1947

By Henry J. Sandri

ACQUISITION JUSTIFICATION There are many reasons why companies consider acquisitions as a means to expand their operations. Some wish to reduce the impact of business cycles on their businesses. Others seek firms within the same industry for expansion and increased market share. Still others diversify in order to avoid takeovers. Whatever the reasons or justification, an evaluation of an acquisition candidate should be systematic and thorough. To many financial managers the concept of a systematic acquisition evaluation indicates the need for a regular set of evaluation criteria. While these are available from numerous sources, one basic parameter frequently overlooked is the application of these criteria to an industry which is different from the acquirer. This becomes particularly important when evaluating firms within the mineral industry. The mineral industry is significantly different from other industries to require different valuing techniques. • This paper will present a number of reasons why an acquisition candidate in the mineral industry should be evaluated differently from other acquisitions, including by other mineral firms. Additionally, this paper will review the most appropriate means of valuing a mineral firm. • Firms considering the acquisition of a mineral firm should understand the nature of the industry before ever making a tender offer. Some of the general considerations include the following: • Level of Capital Intensity: In the mid-1980's the start up cost for a gold mine has been between 20-200 million dollars and 500-1,500 million dollars for a bauxite operation. • Global Nature of Competition: Except for certain industrial minerals, most minerals and metals are traded worldwide and many on national exchanges, such as COMEX. • Start-Up Time: Many mining operations in developed and developing countries have long lead times, 7 to 10 years in some cases, prior to the start-up of production. • Long Term Nature of Investment: For most mineral operations payback usually occurs at least 7 years after production has started. Additionally, many mining operations will continue producing for 80-100 years. • High Level of Risk: The number of factors that a mining firm cannot control such as grade, volume, world supply and demand, plus the long payback periods tend to classify mineral firms at a higher than average risk compared to other investments. • Cyclical Nature: The mineral industry is cyclical in nature, experiencing long troughs and explosive peaks, thus making timing a critical issue. • Labor Intensive: Even with the large capital requirements needed to operate a mine, most mines are labor intensive in proportion to their capital equipment. • Location: Obviously, the nature of this industry requires operators to work in difficult locations, frequently far from civilized localities, in poor weather conditions and without proper supply and distribution infrastructure. One of the most important considerations is an understanding of asset replacement and asset value. Unlike manufacturing concerns, firms in the mineral industry are working toward the elimination, through depletion, of their asset base. Product flexibility is not available to a mining operation. A mineral firm basically has two options as its resource base is depleted: 1) replace the asset with new production, or 2) deplete the asset and close down operation, as in the South African gold mining model referred to later in this paper. An understanding of the

Jan 1, 1985