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By D. M. McFarland

A FEW years ago a novel electric detonator known as the split-second or millisecond delay electric blasting cap was introduced for use in quarry blasting. Regular electric blasting caps fired in series may be depended upon to fire within a millisecond or so from the first to the last in a series. Regular delay electric blasting caps are provided that fire one period after the other period in intervals of 1/2 to possibly 1 1/2 sec. Most split-second or millisecond delays are designed to fire one period after the other period in possibly 25 to 50 millisecond intervals. The ear is not capable of detecting time intervals of this magnitude. The primary thought at the time millisecond de- lays were introduced was to investigate the results on rock breakage by firing a line of holes in a quarry face.so that charges in adjacent holes would not be detonated simultaneously. This could not be accomplished satisfactorily with regular delays. The time interval between successive periods of $5 to 1 sec was sufficient to permit considerable movement of the burden. If the burden of one hole was reduced to a great extent by the firing of an adjacent hole, the firing of the hole with the reduced burden would likely reveal this lack of confinement by a terrific report and wild throw of rock.

Jan 1, 1950

By Mark O. Halverson

In this paper, some applications of remote terminal computer time-sharing to mining geophysics are discussed. Examples are presented and evaluations are made. The evaluations are based largely upon one and one-half years experience with the General Electric Mark I and Mark II systems. In both systems, a terminal is placed at the user's location. The terminal consists of a teletypewriter and a paper tape system. Input is on paper tape or keyboard. The output is printed on paper and may also be placed on paper tape if desired. Available languages consist of BASIC, FORTRAN and ALGOL. The time-sharing system is considered very useful. In large part this is because the terminal is available for use as the need arises, much like a slide rule or calculator. Useage is varied. Geophysical field data can be put on paper tape and be computer reduced, for the most part by clerical personnel. Time-sharing is excellent for statistical studies. The system is adequate to generate geophysical parameter values derived from simple models of the subsurface and to make comparisons with field data.

Jan 1, 1969

By l. Bokányi

The Tóth adsorption isotherm-model was derived and has been widely used for the inhomogeneous solid surfaces. The three-parameter isotherm incorporates the effect of the interaction between the adsorbed substances as well. All classic isotherms can be clearly derived from this one. Bio sorption is the sequestering of dissolved components, i.e. metals from aqueous environment by living or dead biomass. The mechanism of the bio sorption is rather complex and predominantly refers to the affinity of the chemical functional groups: acetoamido groups of chitin, structural polysaccharides, amino and phosphate groups in nucleic acids, amino, amido sulfhydryl and carboxyl groups in proteins, hydroxyls in polysaccharides, sulphates, etc. towards the soluted substances, i.e. heavy metal ions. The physisorption, as well as the micro precipitation also play a role in the bio sorption mechanism. The description of such a complex process can be done by a model reflecting this complexity. According to our experimental results obtained using algae and immobilised algae for the sorption of heavy metal cations, the most appropriate model for such a description is the Tóth-isotherm, the parameters of which can be interpreted. Flotation process is also a very complex one, the overall result of which depends on the partial results of many micro processes and parameters. The particle interaction which very often takes place in the flotation systems makes the phenomenon even more complex. The flotation kinetic model with particle interaction was already introduced by author in 1994 and further developed in 2000. In this paper based on the experimental results obtained with metallic particles in case of recycling flotation the applicability of the Tóth-equation as an alternative flotation kinetic model for the systems with particle interaction is proved. The applicability of Tóth-model in mineral processing demonstrates again its universal character and the great talent of the late József Tóth, great Hungarian chemist. Keywords : Toth isotherm, biosorption, Langmuir, Freundlich

Sep 1, 2012

By Mohamed Ourriban, Yongjun Peng, Qi Liu, Denis Cotnoir

"In the flotation of fine particles, there are two difficulties in general: low recovery of valuable minerals and high recovery of gangue minerals. The low recovery of fine valuable minerals is attributed to low bubble-particle collision and attachment efficiencies, while high recovery of fine gangue minerals is attributed to mechanical entrainment through water films between gas bubbles. Over the last five years COREM has been actively developing fine particle flotation techniques with the objective of improving fine particle flotation separation efficiencies.The fine particle flotation techniques with both generation of micro bubbles and enlargement of sizes of fine particles have been developed to increase bubble-particle collision efficiency. For oxidized fine sulphide minerals, both physical and chemical techniques have been developed to modify the hydrophilic surfaces and therefore increase bubble-particle attachment efficiency. To reduce mechanical entrainment of fine gangue minerals, a new approach, polymeric depression and flocculation, has been developed. By selecting the high molecular weight polymeric depressants to make fine gangue minerals hydrophilic and also enlarge their sizes, entrainment can be minimized. By combining these techniques, we are able to improve both flotation recovery and selectivity in some fine ore flotation systems.INTRODUCTIONWith depleting mineral resources and their declining grades, ores leaving grinding circuit for froth flotation are becoming increasingly finer to achieve mineral liberation. Together with the increasing demand for minerals, ever-increasing tonnages of fines are being produced. Therefore, flotation of fine particles is an immense challenge to be tackled by researchers all over the world today."

Jan 1, 2006

By Newell G. Alford

COAL companies are definitely becoming conscious of the need for better organization. Mechanized mining and the intricate preparation of coal have brought with them the demand for better trained and more highly skilled mining personnel. Refinement in coal mine management is increasing the demand for young graduate engineers to start in the lower grades of the reorganization and prepare themselves to meet rapidly increasing coal mining responsibilities. The interest is wide in scope and extends from self-helps, extension work, and management study at the mines to stimulation of interest in coal mining amongst undergraduate mining students, leading to their permanent employment after graduation. Data by the United States Bureau of Mines show the total annual value of coal production (bituminous and anthracite in the U.S.) through the past 22 years as being more than 38 per cent of the combined value of all ocher mineral industry products. Natural-gas production has gained rapidly on coal since 1916; petroleum exceeded coal beginning with 1934 (see Figure 1). For this 22-year period, the Committee on Student Interest in Coal Mining, in the A.I.M.E., made a survey of the mining schools in Canada and the United States to show the approximate absorption of young graduate mining engineers by the coal industry. In 1938, 232 mining engineers were graduated as compared with 42 in 1918 (a war year) and 180 in 1923. From 1923 to 1929 the graduates declined to another low of 90, but from there on there was a rapid annual increase in the graduating output, reaching a total of 232 in 1938 and continuing upward to a maximum of over 325 graduating this present month.

Jan 1, 1940

By F. Y. Grepe

"THE MOST common type of mine hoist is, as is very well known, that in which the a.c. wound rotor motor is the driving medium. The reasons for the use of the wound rotor motor are, of course, economic. This type of equipment has, during the years, proved to be very reliable and reasonably satisfactory. It is, in fact, still being installed and in some places where a very hard and exacting duty cycle is demanded. As an example, a 600 h.p. 2,300-volt job was recently installed at the Caledonia mine (1) at Glace Bay. This is a vertical. hoist in a shaft only 175 feet deep but it is, nevertheless, working hard bringing coal to the surface and in making a trip at a speed somewhat better than every 20 seconds.The control equipment for such installations usually consists of a pair of primary reversing contactors which are interlocked both mechanically and electrically, together with some form of secondary controller. This, in the case of small hoists, can be a drum controller and metallic resistors or, in the case of larger hoists, a magnetic contactor panel and metallic resistors or, alternatively, can be one of the various forms of liquid rheostats which are available. The liquid rheostats, if of the dipper type, may be manually operated or it may be operated by some form of servo motor mechanism. In the weir type of liquid controller, the electrolite is, of course, pumped in and out of the rheostat."

Jan 1, 1954

By Sharif Jahanshahi

Calcium ferrite slags are often associated with Professor Yazawa due to his pioneering work on the thermodynamics of this type of melts. Over the past years CSIRO has invested some effort in studying physico-chemical properties of such melts to fill in some gaps in our knowledge and explore opportunities for application of the understanding developed. These investigations cover thermodynamics, transport properties of calcium ferrite based slags, as well as the kinetics of reactions of such slags with refractories. The present paper provides an overview of some of these studies and highlights some of the interesting behavior of such melts, The oxidation state of copper and arsenic in calcium ferrite based slags are predominantly Cu+ and As3+, respectively, at oxygen potentials below 10-7 atm. The concentration of CU2+ in such slags becomes significant at oxygen potentials of greater than 10-7 atm at 1300 °C. The activities of CuO0.5 and AsO1.5 in calcium ferrite slags show strong deviations from the Raoultian Law, while that of CoO is very close to ideal behaviour with respect to pure solid CoO. Addition of SiO2 to calcium ferrite slags can have significant effects on the activities of FeO and Fe2O3 and hence the stability of magnetite phase. Transfer of oxygen in calcium ferrite slags is fast with diffusivity of 2x 103 cm2/s at 1350 °C and activation energy of 16 kcal/mol. Presence of solid phases, such as magnetite, has pronounced effect on the viscosity of calcium ferrite slags. The observed dependence on solid loading and shear rate indicates deviation from Newtonian behaviour. The interfacial tension between copper mattes and calcium ferrite slags is strongly dependent on the matte grade, with the determined values being much lower than the corresponding ones for interfacial tension between similar mattes and iron silicate slags. MgO, Cr2O3 and MgCr2O4 have low solubility in calcium ferrite slags and their solubility increases with increasing copper oxide content of the slag at 1300°C. The oxidation state of the slag has strong effects on phase transformation, dissolution rate and disintegration of refractories in calcium ferrite slags. Other key factors with major impact on slag-refractory interactions include viscosity and surface tension of slags as well as the contact angle between slag and refractory material,

Jan 1, 2003

By Sharif Jahanshahi

Calcium ferrite slags are often associated with Professor Yazawa due to his pioneering work on the thermodynamics of this type of melts. Over the past years CSIRO has invested some effort in studying physico-chemical properties of such melts to fill in some gaps in our knowledge and explore opportunities for application of the understanding developed. These investigations cover thermodynamics, transport properties of calcium ferrite based slags, as well as the kinetics of reactions of such slags with refractories. The present paper provides an overview of some of these studies and highlights some of the interesting behavior of such melts. The oxidation state of copper and arsenic in calcium ferrite based slags are predominantly Cu+ and As3+, respectively, at oxygen potentials below 10.1 atm. The concentration ofCu2+ in such slags becomes significant at oxygen potentials of greater than 10'1 atm at 1300 ?C. The activities of CuOo.s and AsOl.S in calcium ferrite slags show strong deviations from the Raoultian Law, while that of CoO is very close to ideal behaviour with respect to pure solid CoO. Addition of Si02 to calcium ferrite slags can have significant effects on the activities of FeO and Fe2O3 and hence the stability of magnetite phase. Transfer of oxygen in calcium ferrite slags is fast with diffusivity of 2xlO?3 cm2/s at 1350 °C and activation energy of 16 kcal/mol Presence of solid phases, such as magnetite, has pronounced effect on the viscosity of calcium ferrite slags. The observed dependence on solid loading and shear rate indicates deviation from Newtonian behaviour. The interfacial tension between copper mattes and calcium ferrite slags is strongly dependent on the matte grade, with the determined values being much lower than the corresponding ones for interfacial tension between similar mattes and iron silicate slags. MgO, Cr2O3 and MgCr2O4 have low solubility in calcium ferrite slags and their solubility increases with increasing copper oxide content of the slag at 1300 °c. The oxidation state of the slag has strong effects on phase transformation, dissolution rate and disintegration of refractories in calcium ferrite slags. Other key factors with major impact on slag-refractory interactions include viscosity and surface tension of slags as well as the contact angle between slag and refractory material.

Jan 1, 2003

By T. S. Fuller

THE work of D. J. McAdam1,2 at the U. S. Naval Engineering Experiment Station, Annapolis, Md., on what has been called by him "corrosion fatigue" has focussed the attention of the engineering profession in general, and of those interested especially in the study of corrosion in particular, on the importance of making tests which will indicate as nearly as possible what can be expected from a given material in service. Pitting is unquestionably the chief agent operating so tremendously to reduce fatigue limits, but in the light of previous work3, 4, 5, 6, 7, 8 it is fair to assume that absorbed hydrogen resulting from the action of the corroding medium upon steel may, under certain conditions, have a perceptible influence. The experiments described in this paper deal more precisely with stressless corrosion, or "prior-corrosion fatigue, "9 and have been carried out to test such an assumption, to segregate, if possible, the effect of pitting from that of absorbed hydrogen, and although very preliminary in nature they indicate results which are striking.

Jan 1, 1929

By C. G. Dunn

IT is well known that plastic deformation alters many of the properties of a metal and subsequent heat-treatment partially or completely restores these properties.1 In the deformed or strained state, the metal is unstable and tends to change toward a condition called a "strain-free state." The transformation occurs through recovery, recrystallization, and grain growth-processes that may take place singly or in combination. The distortion of the lattice of an individual grain of a metal in a state of strain may be rather complex in nature, because plastic deformation produces: (I) dislocations within mosaic blocks; (2) elastic variations of the lattice spacings; and (3) gross alterations throughout the lattice, especially along slip planes, along composition planes between a grain and its mechanical twins, and along boundaries of deformation bands. These gross alterations are of the nature of bent planes or rotated regions of the crystal lattice and are revealed by a spread in the orientation of the grain. Although we cannot describe these strains and their formation accurately because of insufficient knowledge, we can, nevertheless, use the information as well as possible to obtain a better understanding of recovery processes. In recovery, the lattice of a grain is not made anew as it is in recrystallization, but is improved or mended in such a way that the basic structure remains unaltered. Until recently observations were that recovery produced no marked changes in the shapes of spots in Laue diffraction patterns, whereas recrystallization did, but now it is known for silicon ferrite2 that Laue spots may become quite sharp entirely through recovery. Consequently, the shape of Laue spots alone would not be a suitable test to distinguish between recovery and recrystallization. There is considerable evidence that the micro- structure usually does not change visibly during recovery. Absence of a visible change in the microstructure, therefore, provides a sufficient test of recovery in many cases. However, including this observation in a definition of recovery as a necessary condition (this is usually done) is unfortunate, because recovery may, as will become evident later, produce new grain boundaries that are visible not only in the microstructure but also in the macrostructure. For the present, therefore, let us say that a necessary condition for a process to be one of recovery is that the principal orientation or orientations of a deformed grain be essentially unchanged throughout the transformation toward the strain-free state. Several transformations may occur that fulfill this condition, and the nature of the distortion in a grain indicates what these must be if the lattice is to be mended in part or fully. Consequently, it will be convenient as well as

Jan 1, 1946

By G. Goodlad

This paper describes some of the main aspects involved in implementing the European “Equipment and Protective Systems for Use in Potentially Explosive Atmospheres” (ATEX) Directive (No.94/9/EC) in the British mining industry by the year 2003. It provides a brief background to the Directive and considers its main objective of removing all barriers to trade in Europe. It outlines the need for the European Standards making bodies to write new editions of the ’explosion protection concept standards’ and for manufacturers to adopt new quality management procedures and develop new versions of equipment in conformity with the ATEX categories of “M1” or “M2.” Finally, it assesses the possible future relationship between the European enforcing authorities, manufacturers and users of explosion protected equipment.

Jan 1, 1999

By V. A. Cooney

Introduction For the compliment paid me by the Institute's kind invitation to speak this afternoon, I am very grateful. For the astuteness of your officers in determining that encouragement should be given, through the medium of a paper, towards accident prevention in coal mines, the coal industry cannot but be grateful. Some day, and let us hope soon, a more developed paper may supersede this one. In the meantime, if some knowledge of what one coal field has been able to accomplish, even in the initial stages of its effort, will induce other fields and other sections of the mining industry to launch similar experiments, much good will result and a more developed dissertation on the subject will make its appearance.

Jan 1, 1946

By W. K. A. Congreve

Introduction Less than a hundred years ago the engineer was able to do his job without concern for the science that underlay his practices or for the men who operated his machines. But toward the end of the last century science began to be applied to industry, and its success was such that the plant which clung to empiricism was unable to compete with the plant that followed science. Even more recently, the engineer has been forced to consider the men who operate his machines, for modern large-scale industry has given these men education, social security, and power. Hence the engineer can get good, steady labour to operate his machines only if he can offer inducements. Wages are in general outside the control of the engineer, but he is able to control working conditions. This essay is concerned with one factor of good working conditions: safety. The writer became interested in this problem during three months' summer employment as a student at the Sullivan concentrator of the Consolidated Mining and Smelting Company and was surprised at the distance his investigations led him from the field of pure engineering into the fields of psychology, education, and publicity. Nevertheless, because safety has to do with machines and with men who operate machines, and because it profoundly affects plant efficiency, it is the job of an engineer, not of a psychologist or teacher, nor of the salesman publicity expert who is often so unfortunately employed in personnel relations. The size and complexity of the subject has limited the scope of this essay to the consideration of only a few aspects of industrial safety. Considerable attention has been given to the underlying principles, but the mechanical side of accident prevention, the design of equipment, erection of guards, etc., and the very important problems of organization and administration, have not been given attention proportionate to their importance.

Jan 1, 1948

By Carl S. Westerberg

Coal preparation practice and trends follow, among other factors, production trends in any given area. Considering an area the size of a state, some broad predictions may be made after a review of the annual production records. As this paper is concerned with coal cleaning in Utah, data on its production record are pertinent. Table 1 shows the percentage relation of coal production in Utah to the national total as a single figure up to 1935 which includes all recorded production. From 1935 through 1947 these data are presented by years. It is evident from these data that the production of Utah coal is ascending. The reason for this trend is industrial growth in the West resulting in a population shift which accounts for more people than the normal increase would supply together with Utah's relatively fortunate geographical location and its abundance of good-quality coal. Utah is also hopeful of supplying more coal in the future for West Coast power generati0n.l

Jan 1, 1949

By Edward Sampson

Bases of National Power At a time when the economy of the world is in a particularly troubled state it is appropriate to examine some problems of the distribution of natural resources. I should like particularly to call attention to the remarkable increasing demand for natural resources, to give an analysis of the demand for certain mineral resources, and to direct attention to some problems in satisfying this demand. All industrial power is based on natural resources and the most basic of these are soils, energy resources, and mineral resources. There is a strong interrelation of these resources, more than is obvious, and I shall take up certain aspects from the point of view of a geologist. Few nations are well endowed with all three of the kinds of natural resources I have mentioned and much has been done by some small countries whose peoples are industrious and enterprising and where conditions for free world trade have been favourable. However, major industrial power is dependent on a substantial endowment of all three classes.

Jan 1, 1949

By E. W. Lucht

THE term "high pressure", as used in industry today, is applied rather loosely. Generally, it refers to pressures that are higher than those encountered in most industrial processes although no definite limits are normally stated. For the purpose of this talk I should like to set rather arbitrary limits to the term "high pressure", and in ab-solute figures this would be the range from 1000 psi to perhaps 40,000 or 50,000 p.s.i. The scope of high pressure technology is very broad, and it would take more time than we have avail-able here today to cover fully even one aspect of the field. Therefore, I should like to discuss just some of the techniques used and problems en-countered in high pressure operations. Research work into the high pressure region dates back about 150 years, but it was not until 1910 that the first commercial application of high pressure technology was made in the production of ammonia.

Jan 1, 1962

By F. W. Willard

VIEWING with alarm is a preoccupation not exclusively the habit of the political spellbinder. In good faith many of our mineral technologists have been and are genuinely alarmed over the prodigal consumption of our mineral reserves. Most competent observers are cautiously pessimistic. There are sound technical reasons for such caution. It is the purpose of this paper to discuss some of those reasons without benefit of a gift of prophecy. Perhaps the outstanding reason for caution is ignorance of accessible but undiscovered mineral reserves. The petroleum technologists have an edge on their metallurgical brothers for they have better tools for exploration. This is not to say that the mining geologist has to depend on hunches or the divining rod. The outstanding work on orogenesis by Lindgren and others has provided the mining geologist with some sound scientific knowledge as to where accessible metallic minerals are most likely to be found, As Clinton H. Crane has recently observed, most of the accessible areas of the earth have been combed for easily identified outcrops, and those have been or are being actively exploited. To find ore bodies hidden below the surface is still a costly speculation.

Jan 1, 1946

By Gerald Blackmore

This paper discusses the present state and future trends within the coal industry, and then goes into the reasoning behind these planned trends. Such factors as marketing, costs, new mining techniques and machinery, and manpower and human resources are considered. Finally, the author refers to the effect that these trends will have on the coal industry of Cape Breton.

Jan 1, 1968

By S. A. TAYLOR

THERE is probably no other mineral industry of which the public has as much information and misinformation as it has of the coal industry. Unfortunately, however, the general public's knowledge of the coal industry, outside of the particular kind of coal it is accustomed to, by reason of use, is largely made up of information received from newspaper and popular magazine articles, in which the mine workers are depicted as overworked and mistreated men, and the coal operators as "coal barons." Those who have any specific knowledge of exact conditions in the coal industry know how unjust and un- fair such an opinion of the coal industry is, not only to the miner but to the operator as well. Many reporters and writers of magazine articles are misled by statements regarding the condition of the miners that are exaggerated and not founded on facts and, if an investigation of the conditions of the miner's work, his habitation and surroundings were fairly made, it would at least compel more truthful statements by those who write for public reading. That such an investigation would not reveal anything that was wrong, or anything to be censured or cured, no one, I think, would maintain, but I do think that any fair investigation of the facts would show that conditions in and around the newer and later-developed coal mines and communities would compare favorably with those of manufacturing districts, and that where the mines and com- munities are old and not very attractive places to work, or live in, they carry with them other considerations, compensating for these conditions, and cannot be remedied by reason of a lack of sufficient coal to warrant economically any costly changes.

Jan 1, 1926

By F. B. Richards

THERE has been much interest recently in the iron ore supply of the Lake Superior district. It may be of interest to this meeting to give some thought to this situation, dealing more particularly with the present great iron ore deposits of this section. Ores from its various iron ranges are the foundation of the tremendous tonnage of steel and iron of all kinds produced in the territory along and adjacent to the Great Lakes, drawing the bulk of its supply from this northwestern ore country. For a number of years estimates have been made of the quantity of available ore. The latest study, by M. C. Lake, chief geologist of the M. A. Hanna Co., is of great interest and brings the estimated tonnage to Jan. 1. 1929.

Jan 1, 1930