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By A. F. Banks

INTRODUCTION Selective flocculation as a method of desliming potash flotation plant feed has been in commercial use since November, 1974.l It was installed to replace a 1ess efficient mechanical desliming process. While most plants operating in the Saskatoon area of Saskatchewan were designed for 4% to 5% insolubles in practise the quantity and quality of the insoluble materials in the ore has been variable. The variability of the ore has contributed to less than optimum efficiency in the desliming and consequently, the potash flotation circuits. This lower than expected efficiency contributed to the commercialization of a patented process2 through large scale pilot plant testing. Referring to published information and experience, the application of selective flocculation-flotation of slimes to sylvinite ores will be compared with the more conventional mechanical methods of desliming. THE ORE The ore beds being mined in the Saskatoon area of Saskatchewan have proven to be much less uniform than originally thought (Figure 1). The insoluble content of the plant feed is variable in both quantity and quality due to two factors, the presence of disturbances and the structural weakness of the mud seams immediately above the ore beds. Some alteration of the insolubles in the vicinity of disturbances has made them more difficult to liberate and makes ore from the disturbed areas less amenable to treatment.

Jan 1, 1980

By Richard P. Rothwell

The communication which I hare to lay before my fellow-members of the Institute, is no elaborate paper, nor the statement of any great discovery; it is simply the record of convenient methods of conducting topographical survey?, and of keeping the notes of the same; methods that have grown out of practical experience, and have saved me many a day's labor by facilitating office and field work, and at the same time secured a greater degree of accuracy than is obtained by the methods now in general use. I assume it as granted that no topographical map is worthy of the name, except it represent the elevations and depressions of the surface by means of horizontal or contour lines. In the Ordnance Survey of Great Britain, the contour lines are traced for every fifty feet vertical height, I believe, by running out the line with level and compass through all its meanderings on the surface; this, of course, is a very tedious, though accurate process, but " in the woods," where many of our surveys have to be made, it would be practically impossible. Some time ago, I made an extensive and quite elaborate topographical survey and contour map of the southern portion of the Cahaba coal-field, in Alabama, the object of the survey being to

By Richard P. Rothwell

THE communication which I have to lay before my fellow-members of the Institute, is no elaborate paper, nor the statement of any great discovery ; it is simply the record of convenient methods of conducting topographical surveys, and of keeping the notes of the same; methods that have grown out of practical experience, and have saved me many a day's labor by facilitating office and field work, and at the same time secured a greater degree of accuracy than is obtained by the methods now in general use. I assume it as granted that no topographical map is worthy of the name, except it represent the elevations and depressions of the surface by means of horizontal or contour lines. In the Ordnance Survey of Great Britain, the contour lines are traced for every fifty feet vertical height, I believe, by running out the line with level and compass through all its meanderings on the surface ; this, of course, is a very tedious, though accurate process, but "in the woods," where many of our surveys have to be made, it would be practically impossible. Some time ago, I made an extensive and quite elaborate topographical survey and contour map of the southern portion of the Cahaba coal-field, in Alabama, the object of the survey being to

Jan 1, 1875

The Institute conducts jointly with the American Society of Civil Engineers, American Society of Mechanical Engineers and American Institute of Electrical Engineers, certain activities as listed below, and is joint owner with them of certain properties. United Engineering Trustees, Inc. When Mr. Carnegie made his gift which made possible a home for the engineering societies, a separate corporation was organized to act as a holding company and to manage the common property. This was long known as the United Engineering Society, but the name has now been changed to one which more nearly reflects the real function of the corporation. It holds title to the Engineering Societies Building and to various funds placed in its charge and is managed by a Board of Trustees, of which three are chosen by each of the four societies, American Institute of Mining and Metallurgical Engineers, American Society of Mechanical Engineers, American Institute of Electrical Engineers and American Society of Civil Engineers, which have equal and undivided interests in the property. The land and building cost two million dollars. The interest of the Founders societies, aside from especial trust funds, is now valued at $1,987,793. The A. I. M. E. trustees are William H. Bassett, H. G. Moulton and R. M. Roosevelt. The President of the Board is Harold V. Coes and the Secretary, Alfred D. Flinn.

Jan 1, 1934

Nature: Man is but one of the creatures which in- habit the earth, a dust speck in the universe. Thinking man has been concerned with his place and purpose in the universe since the earliest Egyptian and Chinese philosophers. Ancient creeds, as well as modern religions and philosophies of life, were concerned with the same problem. While such considerations and concepts have been valuable, theoretical philosophizing and dogmatic concepts are inadequate for a satisfactory solution of world problems of today. The concepts of man and life and their ultimate purpose should be sought in the relations of intelligent man to man and their relation- ship to the physical world. The quintessence of nature's accomplishment-man- is also the greatest disturber of nature and the greatest enemy of his own kind. While his spirit and mind defy and overcome natural limitations, his physical self is controlled by the same basic biochemical laws that govern any other form of living matter. This paradoxical duality of human voluntary and involuntary relations to nature is the source of the perpetual conflict between mind and matter. Therefore, the higher the spiritual evolution and perfection of the individual's mind, the greater and deeper the conflicting elements in their expression; and conversely, the simpler the mind or the mental and spiritual heritage, the less is the individual concerned with the conflicting elements.

Jan 1, 1950

By R. K. Datta, T. S. Davis

YVO4:EU, excited under 3650A radiation, shows a marked increase in total brightness with in~rease in temperature. At 25°C the response to 3650A radiation is about 48 pct of its maximum response which occurs at about 350°C, Fig. 1. In an attempt to explain the phenomenon, one of the present authors' (R.K.D.) investigated the diffuse reflectance spectra of the phosphor at different temperatures (up to -150°C) and was unable to observe any significant change to which the increased brightness could be reasonably ascribed. Since then diffuse reflectance spectra at elevated temperatures have been obtained in this laboratory using an improved device. A significant decrease in the diffuse reflectance of a phosphor in the ultraviolet region—especially in the longer wavelength region—at -300°C has been observed. The purpose of this note is to describe the device used for high-temperature reflectance measurements and to explain the increased brightness of YVO4:Eu phosphor at elevated temperatures under 3650A excitation. Experimental. YVO4 and YVO4:Eu samples were prepared as previously described.' The elevated-temperature reflectance spectra were obtained with a Cary 14 spectrophotometer equipped with a diffuse reflectance accessory and a ring collector. CaF2 was used as the standard. The cell used

Jan 1, 1969

By Alvin F. Kroll

BUNKER Hill & Sullivan Mining & Concentrating Co. has three major sources of ore at present: high grade square-set ore, low grade caving ore, and low grade reclaimed washed jig tailing. These three ores constitute the feed to the 3000-tpd concentrator that produces lead-silver, zinc, and pyrite concentrates. Each ore has different characteristics of grindability, mineral particle size, composition, and content, but all are amenable to the same mill circuit and reagents. The gangue is primarily quartzite. The Bunker Hill concentrator is now using a coarse primary grind followed by a regrind of sand fractions of lead rougher tailing, lead middling, and lead cleaner tailing, and further regrind of sand fractions of zinc middling and zinc cleaner tailing. This is done in order to recover all valuable minerals at the largest size possible. The tendency to overgrind the ore particles, which are more easily ground than the gangue particles, is thereby reduced-lessening their loss in the flotation tailings. The coarse primary grind and regrind method has the advantages of: providing more selective grinding, minimizing sliming, giving a cleaner lead-zinc separation, and reducing mill requirements for reagents and water. Improved lead-zinc separation raises overall recovery and also increases lead and zinc recovery in the respective concentrates by keeping middling particles out of concentrate and tailing.

Jan 6, 1954

Advantages to Members of Our Advertising Section.-It is our intention to make the advertising section of the Bulletin as comprehensive as possible, so that members can turn to it for complete information as to where to buy the best mining and metallurgical supplies at the lowest prices. No firms or supplies of dubious reputation are advertised in the Bulletin. If members, in buying any material, will refer to the advertisement of that material in the Bulletin, or if they do not find it advertised in the Bulletin, will, when ordering, ask the manufacturers why the goods were not advertised in the Institute publication, it will be of material benefit to all of us, because the chief reason why advertisers are unable to trace direct results is because purchasers do not mention the Bulletin when writing. Finally, if members, when in need of anything whatsoever, will write to the Institute headquarters, an effort will be made to send them a complete list of manufacturers able to supply the desired materials of good quality. The furnishing of these lists will be a benefit to our Advertising Department, as well as to the members. We need scarcely call attention to the advantages obtained by the members from the money which advertising brings in, because all this money is returned directly to the members in one form or another.

Jan 7, 1913

By George Anagnostache

AMONG the petroleum-producing countries of the world, Roumania occupies the fifth place; in Europe, it occupies second place, coming after Russia. The extraction and the use of petroleum in Roumania, may be trace( as far back as 1856, but the production on an industrial scale started in 1896, when the "Steaua Romana," was formed. From that time until the beginning of the war, the petroleum industry had a rapid growth the number of the producing companies increased to 37, and production FIG. 1.-ROUMANIAN OIL AND GAS FIELDS. increased from 81,571 tons, in 1896, to 1,898,545 tons, in 1912, when the greatest production was reached. In 1916, when the Germans invaded Roumania, the oilfields, at the order of the Allies and under British supervision, were destroyed, to pre vent their exploitation by the Central Powers; the wells were blown in the refineries and the storage tanks burnt, and pipelines put out of order This voluntary destruction, which weakened the resistance of the Central Powers, set back the petroleum industry at least one decade. Reconstruction after the war was slow, because of bad transportation conditions the scarcity of drilling and refining material, the insufficiency of. electric power, and the continuous depreciation of the Roumanian money, which made difficult the buying of the necessary materials for reconstruction.

Jan 3, 1925

By Edgar S. Burkhardt

In mining, the process of comminution starts at the pit and ends at the classifiers. The first machine that breaks or comminutes ore is the primary crusher. There are many types of crushers, but the one most commonly used in large tonnage plants is the gyratory so discussion is restricted to this type of machine. See Figure 1. The primary crusher is the most important piece of comminution machinery in the plant because every ton of ore processed by the concentrator must pass through it, as shown in Figure 2. Most plants can operate if a secondary crusher or a mill is shut down, but if the primary crusher stops, the whole concentrator goes down. It is, therefore, important that the machine be able to produce sufficient ore to keep the concentrator running without hesitation. The plant designer first considers the required daily capacity and an estimate of the size of the ore from the pit. To this he adds an availability factor to compensate for delays due to shovels, trucks and rou- [ ] tine maintenance at the crushing station. This factor is based on experience and can be on the order of 75% (1). With these figures, he determines the hourly capacity required of the primary crushing station to keep the concentrator supplied. See Table I.

Jan 1, 1982

By Bjorn Bolviken

Bjorn Bolviken (Geochemist, Geological Survey of Norway, Trondheim, Norway)-Under the heading "Recognition of Anomalies," the author states, "If the frequency distribution is actually log-normal, the probability of these high values being part of the background population is small (less than 0.023 and 0.0013 for 2 and 3 standard deviation, respectively)." The figures quoted seem to be the probabilities of these high values being the mean rather than part of the background population unless "background" is defined as one single concentration. If the background is considered to be a statistical distribution of concentrations,50 (which is probably the case here since the author uses the term "background population"), the probability of any observed value being part of the background may be estimated through a calculation of the number of observed values that are in excess of (or below) the number expected to belong to the background. Apparently, some confusion exists in the literature regarding this point. Many authors accept the concept of background as being a statistical distribution, but do not seem to recognize the consequences of this concept. One of these consequences would be that the background of a chemical element should comprise any concentration between zero and a theoretical maximum, which is governed by the chemistry and mineralogy of the material

Jan 1, 1974

By J. J. Kanter

A. I. Blank.*-—Mr. Kanter has spoken of failures from causes other than creep itself in metals that are subjected to creep stresses. Would it be possible for the author to enlarge on this very important matter of "cataclysmic types of failures? " J. J. Kanter.—Of course, it is always a delicate matter to discuss specific failures. I would prefer to keep the present discussion on fundamentals and principles. H. L. Burghof.*—Mr. Kanter, I should like to ask what you consider the responsibility of the designer in avoiding stress concentrations that would lead to these types of failures? J. J. Kanter.—lt was my feeling in looking over the papers of this symposium that they were significantly lacking in consideration of what happens to the metals when strained under conditions that lead to rupture. Often creep tests are run that produce only a fractional percentage of the deformation, in several thousand hours. That kind of information gives the designer no assurance whatever that cracks will not result in his structure at points where stress concentrations, and therefore deformation concentrations, exist. I think anyone in this day and age who presents a paper on creep should incorporate with those studies a thorough investigation of creep rupture if it is expected to make an impression upon the design engineer.

Jan 1, 1945

By A. Lee Barrett

THE Maintenance Committee of the Coal Division of the American Institute of Mining and Metallurgical Engineers is presenting with this report the first of a series of cost comparisons which it plans to present to the Institute. The plan is to assemble maintenance cost on all equipment connected with mechanical operations at the face of coal mines, to arrange these costs by districts, to make comparisons between districts, and within districts. This particular report covers data with respect to mobile loading machines, including both "on-track" and "off-track" equipment. It is anticipated- in-fact, considerable data have already been accumulated-that next year complete maintenance costs by districts can be presented for complete loading units, including the various classes and combinations of on-track and off-track equipment. Data have also been collected with respect to some phases of maintenance methods and certain recommendations of the committee are included dealing with maintenance problems. In the assembly of these data more than 120 questionnaires were sent to operating companies through- out the United States. At the time the report was written 33 questionnaires had been returned with completed information and an additional group of companies had written that the information requested was not at present available but that they hoped to have such information available in the not far distant future. The replies as

Jan 1, 1946

By Glenn M. Boyce

This paper discusses the results of a laboratory testing pro- gram to determine the validity of hydraulic fracturing stress measurements in salt. Tests were performed on 15 cm diameter samples loaded under hydrostatic stress conditions to determine the influence of time, confining pressure, flow rate, borehole diameter, and packers on breakdown pressure. Tests were also performed in a polyaxial loading frame to determine whether or not hydraulic fracturing could be used to measure non-hydrostatic stresses. The test results indicate that the breakdown pressure is not affected by time delays of up to 64 hours between the application of load and fracturing the rock. Breakdown pressures were found to fall short of predicted elastic values at higher confining pressures for the hydrostatic tests. The ratio of the horizontal stresses in non-hydrostatic tests had no effect on breakdown pressures. Flow rate and borehole diameter variations were found to have a marked effect on breakdown pressures. Shut-in pressure values, which are generally used as an indication of the minimum stress value, exceeded the applied minimum stresses by 10 to 60% depending on the method of determination used. The lack of a relationship between breakdown pressure and horizontal stress ratio may preclude hydraulic fracturing from being used in salt as it is conventionally applied in brittle rocks.

Jan 1, 1984

By William C. Aitkenhead, John A. Jaekel

Uranium deposits in the Spokane Indian Reservation, as well as those around Mt. Spokane, are essentially low grade, much of the ore containing less than 0.2 pct U808. The Mining Experiment Station of the Division of Industrial Research, State College of Washington, has been engaged in intensive research on the amenability of these low grade ores to froth flotation. The results: successful flotation of autinite, chief mineral constituent. At the outset of this work the goal was a concentrate of 1 pct U308 with a 90 pct recovery from ores containing less than 0.2 pct U3O8. Most of the work has been done on argillite ore from the Midnight mine on the Spokane Indian Reservation. The goal has not been attained using this ore, but samples of the granite ore from Mt. Spokane yielded successful results. For example, a concentrate containing 11.2 pct U308 was produced from a Mt. Spokane high grade ore containing 1.27 pct U3O8 with a recovery of 97.8 pct. Another Mt. Spokane ore yielded a concentrate of 5.0 pct U3O8 from an ore containing 0.13 pct U3O8, with a recovery of 85 pct. This same ore gave a recovery of 93.5 pct when the grade of concentrate was reduced to 2.0 pct.

Jan 1, 1959

By Colin Rae

THE absence of paraffin and other oil hydrocarbons in the soil, although they are concentrated in extensive deposits in some localities, the common distribution of plant remains through many formations that .are not productive for oil, and many other factors, seem to indicate the existence of an intermediate organic compound between the complex plant compounds and the petroleum hydrocarbons; and much evidence points to the humus acids or associated organic compounds, which are probably collected by surface waters and concentrated in certain areas by means of precipitation by electrolytes, which would be contained in sea water or possibly in various inland seas or lakes. PRESENT-DAY EVIDENCE There are many present-day evidences of the association of petroleum with humus acids. Binney, in 1912, made observations without explanations on the peat mosses of Down Holland, England, where he found petroleum being formed by decomposition, in the presence of an infiltration of sea water. The analysis of a typical peat will show its relationship to the humus acids under consideration. SAMPLE 'No. 1, SAMPLE NO. 2, PER CENT. PER CENT. Water : 20.0 29.5 Ash 3.0 3.05 Fiber 47.0 54.95 Humus acids 30:0 12.50 J. D. Haseman and others have noted the association of asphalt and hydrocarbons with the swampy, boggy areas, particularly adjacent to the sea.

Jan 2, 1922

By A. L. Holley

The three principal mines from which the celebrated Salisbury iron ores are obtained are called respectively the "Old Hill," "Davis," and "Chatfield" ore beds, and are situated in the town of Salisbury, Litchfield County, Conn., on the eastern slope of the Tocconuc range of hills.* The Old Hill Ore Bed is a tract of land of 100 acres, originally granted by the General Court in October, 1731, to be laid out by Daniel Bissell of Windsor. It mas Boon after surveyed and located by Ezekiel Ashley and John Pell. The descendants of Ashley are still proprietors in the mine. The supply of ore has been very abundant, and for many years was easily obtained, but latterly the cost of raising has been greatly increased. Up to about 1840 the average yield was estimated to be about 4500 tons per annum. The production has gradually increased until the average yield at present is estimated at 15,000 tons annually. The largest production in any one ymr was about 20,000 tons. The proprietors of this mine were incorporated many years ago under the style of " The Salisbury Ore Bed Proprietors." The Davis Ore Bed, named after an early owner, was originally called Hendricks Ore Bed, and was owned before the organization of the town of Salisbury by Thomas Lamb, one of the first settlers

Jan 1, 1879

By W. R. Ingalls

DURING 1921, the Oklahoma mines dominated the American zinc-producing industry. They comprised the only group that could produce under the adverse conditions that prevailed. At the beginning of 1921, there were about 34 mills in opera-tion in the Tri-state District, out of a total estimated variously at 150 to 200, and these were producing at the rate of about 5000 tons of blende concentrate per week. At the end of 1921, there were about 50 mills in operation. The Tri-state District rates about 80 men to the mine and mill, on-the average. SMELTING The zinc smelters-in 1921 experienced a disastrous year. All of them operated at greatly reduced capacity and probably most of them suffered loss in operations. Smelting costs came down to a considerable extent by virtue of drops in the price for coal, wage reductions and more efficient work, but these ameliorations were insufficient to enable the smelters to come out even. In the Illinois fields, wages at the end of 1921 had been reduced about 37 per cent. from the peak (middle of 1920), but coal continued to be very dear. The operation of works at a low rate of their capacity was a discouraging and expensive condition. At the end of 1921, the zinc-smelting capacity ,of the United States was as follows:

Jan 7, 1922

Pennsylvania has been a leader in the pageant of industrial America because of her natural mineral re- sources, geographical location, and the ingenuity and industry of her citizens. Brick and other clay products were manufactured in Philadelphia in William Penn's time. Ores of iron, zinc, lead, and copper were mined and smelted in eastern Pennsylvania long before the Revolution. Coal was mined on a commercial basis in the anthracite region as early as 1820 and in the bituminous fields in 1830. The first canals and railroads were constructed to transport minerals and mineral products. Oil was struck at Titusville in 1859. A significant event occurred in 1855-the establishment of the Farmers' High School-Pennsylvania's first attempt to provide higher education for its youth. The Farmers' High School included instruction in geology, mineralogy, and assaying. In 1859 the laws of Pennsylvania transferred to the School the state geological and mineralogical collections formerly located in Harrisburg. Well-informed people are familiar with the effects of the Land-Grant Act of 1862. With inspiring words it established state institutions of higher learning where "the leading object shall be, without excluding other scientific and classical studies . . . to teach such branches of learning as are related to agriculture and the mechanic arts . . . in order to promote the liberal and practical education of the industrial classes in the sev-

Jan 1, 1950

By James R. Cost

The increasing emphasis upon the use of refractory metals has resulted in a closer look at some of the properties of these materials. In the course of a study of the Nb-N system it became necessary to re-examine one such property, the spectral emissivity, e. Experiments were performed in order to determine e for solid niobium as a function of both temperature and nitrogen content. The results of these experiments, which indicate a small but significant correction to the spectral emissivity of pure niobium, are reported herein. In addition, data on the total emissivity, et, of niobium and the spectral emissivity of the nitride Nb2N are given. To this author's knowledge, neither of these emissivities are as yet reported in the literature. Previous studies of the spectral emissivity of niobium have been few. In 1915, Burgess and Waltenburgl obtained a value of 0.49. Whitney? in 1935, used a Mendenhall V to obtain the commonly accepted value of 0.374. A recent investigation of sintering of niobium graphically reported a value of about 0.36= using a solid block of the metal with a blackbody hole drilled into it. In the present experiment a method similar to that of Worthing4 was used. An 8-in. long and 3/16 in. diam hollow tube was formed from smooth surfaced 0.0013-

Jan 1, 1962