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A SELF-RESPECTING miner doesn't wash the cuttin's off his hard hat until he quits his job but, on the other hand, he keeps his lamp clean and a "spot" focus on the work at hand; the former habit is a matter of pride and the latter serves for efficient operation. During 1949, the mining engineer got all the "wet raises" for the problem of cutting costs to meet the drop of metal prices and keeping research work up to schedule when strikes tied up his work were his headaches. We note, not without admiration, that he hasn't washed the muck off his hat in token of surrender but, on the contrary, his light shines bright on the job to be done as can be seen in the following pages. Few people have any conception of how much ore and rock have to be mined and how much sorting it takes to cull a pound of copper from a 1 % ore body. These people would be even more startled to picture the problems faced by the engineer in mining and extracting, profitably, .2 oz of gold from a ton of ore as is done at some of our lode mines. Strikers have sometimes kept our researchers from their pilot plants and research laboratories, but the end of the year shows progress in making ore out of taconite and ferruginous sandstone, with a pilot plant in operation at Aurora, Minn., and plans for one near Birmingham. Unfortunately, it looks as though the mining engineer will have to make John Doe secure in mineral resources in spite of himself. Coal for steel, power, and to warm our homes is still economically possible, in spite of Mr. Lewis, through development of mechanized tools for mining. During the year, the use of continuous mining machines has extended, transport systems are being adopted to keep the ore flowing from the face to the tune of 40 tons per man-shift. Experiments in the gasification of coal are going forward in several places and may eventually extend our fuel reserves by the addition of coal seams now too lean for mining. Liquid fuel from coal, oil shale, or natural gas will become economic when oil consumption exceeds our supply; but, at less than 30 cents a ton direct cost for mining oil shale, the engineer is almost making it competitive under present market conditions. In this age of specialists, the mining engineer is still holding his own as a broad-gauge man. As a matter of fact, he is emerging from a stage of semispecialization as a coal, nonmetallics, or metal mining man to the realization that, with mechanization, mining is fundamentally materials handling whether it is fluorspar, coal, or copper ore. From the coal business come rubber-tired mechanical loaders to the iron mines of Birmingham. Shuttle cars are also finding application in the lead mines of the Tri-State. Open-pit methods are universal. Belt conveyors, trucks, Diesels, and mobile, jumbomounted drills are finding application in all types of mining. In preparation, such methods as flotation,- heavy density, electrical, and centrifugal are finding application in coal, nonmetallics, and metals. These concepts have been recognized by the mining engineer who has kept himself informed and has been quick to seize a method, machine, or a process from another operation and, with ingenuity, applied it to his problems. This, our Annual Review issue, is written by mining engineers. In gathering these separate articles under one cover for publication, we think of it as a trrbute to the tireless energy and skill of these men. They get little of the publicity accorded physicists, medical men, labor leaders, or company executives, but they supply raw materials without which industry would die.

Jan 1, 1950

PAUL D. MERICA,* Washington, D. C. (written discussion t).-This paper is a discussion of some of the results of a recent investigation1 of Prof. Zay Jeffries, and of his interpretation and generalizations from these results. This work I have followed with great interest and with appreciation of its value in clarifying our views on the nature of deformation in metals and its relation to structure. It is only by such close study of the relation of structure to mechanical properties that we shall ever be able to describe the latter in terms of their ultimate elements, and thus explain what are still mysteries in the mechanical behavior of metals; experiment and thought along these lines are in my opinion of the utmost value. If I, therefore, here record some of the difficulties I have experienced in understanding some of the generalizations of Prof. Jeffries, it is only in order that perhaps from the discussion may emerge a clearer and more consistent statement of hypothesis or theory in explanation of the facts discovered by him.

Jan 11, 1918

By R. W. Raymond

I DESIRE to call the attention of the Institute briefly, and by no means in the way of an exhaustive description, to the interesting developments recently made on the east bank of the Hudson River, in the mining of spathic iron ores. The mines to which I refer are those of the Hudson River Spathic Iron Ore Company, situated at Oakhill on Hudson, Columbia County, N. Y., five or six miles from the city of Hudson, and opposite the town of Catskill. The ore occurs in beds, constituting apparently members of the stratified series of rocks on that side of the river, coursing nearly north and south, parallel with the river, and dipping east. The principal outcrops are presented in a range of low hills, about one mile from the river, along the crest, on the western face of which the stratum of spathic ore is more or less exposed. The length of the line in this range, along which, at various openings the ore has been discovered in profitable quantity, is about two miles. To the northward, the hills are somewhat higher, and the stratification may possibly be disturbed, though the rapid examination of the locality which I made in November last did not, include any determination of this

By Dan E. Lewis, William E. Saegart

Similarities of certain geologic and mineralogic parameters are recognized among the various Philippine porphyry copper deposits. Lowell and Guilbert3 described a model of the typical porphyry copper deposit as the result of comparing numerous Western Hemisphere occurrences. Many of the characteristics of the Philippine porphyry copper deposits differ from the model developed by Lowell and Guilbert. A model of the typical porphyry copper deposit is presented and the characteristics of the Philippine model are compared with those of the Western Hemisphere model. Estimated Philippine copper production in 1975 was 242 446 mt. The total in 1948 was 2091 mt. This represents a 116-fold increase in copper production during the 28-yr period. The Philippines now rank seventh in total world production of copper.

Jan 1, 1978

By I. Iwasaki, K. A. Nataratjan

In a previous paper, ozone was shown to remove residual xanthates in flotation pulp solutions as well as to destroy the xanthate coating on bulk copper-nickel sulfide concentrates before differential flotation (Iwasaki and Malicsi, 1985). The oxidation and decom- position mechanisms of xanthate solutions in the presence of commonly used oxidants such as oxygen, chlorine, hypochlorite, bromine, iodine, and hydrogen peroxide at different pH levels have been reported in the past (Rao, 1971). Most of these studies have been restricted to xanthate solutions of pH less than 10. Very few references are available on xanthate decomposition in highly alkaline (pH > 12) solutions (Jones and Woodcock, 1983; Philipp and Fichte, 1960; Tipman and Leja, 1975). No systematic study of xanthate oxidation by ozone has been reported, although its use in flotation has been recognized of late (Allegrini et al., IWO; Ishii et al., 1970; Matsubara et al., 1978). To improve the efficiency of ozone use in flotation, it is essential to understand the mechanisms involved in the decomposition of xanthates with ozone, more specifically, to establish the stoichiometry and decomposition rate. In the present work, a preliminary attempt was made to investigate the effect of pH on xanthate decomposition, and probable mechanisms of xanthate oxidation with ozone.

Jan 1, 1986

By Earl Greiner

THE constitution of the iron-silicon alloys containing from 14 to 33.4 weight per cent silicon has been studied by a number of investigators, whose results have been reviewed in a monograph published by the Engineering Foundation1. In these previous researches, the solubility of silicon in iron was determined by thermal, microscopic or magnetic methods and the compound Fe3Si2 was reported to be stable at tempera-tures from 0 to approximately 1030° C. This paper describes the results of an X-ray investigation of the solubility of silicon in iron and gives data which prove that the Fe3Si2 phase is unstable below 825° C. In order to obtain the present results on the solubility of silicon in iron, the authors have utilized the lattice constants of the alpha-phase iron-silicon alloys given in a previous publication2, and also some addi-tional data which will subsequently be described.

Jan 1, 1936

By William Kelly

An extensive swamp covers a large part of the town-site of Norway and adjacent laud. Through this swamp run two parallel oreformations. In the north one is the Aragon mine. The south one passes into the swamp on the Harrison property. On the edge of the swamp, about 1000 feet from the Aragon mine, a diamond drill, in the fall of 1889, located the ore-bearing formation and a probable ore-body. To explore further and develop this ore, the Penn Iron Mining Company proposed, in the spring of 1890, to sink a shaft. The drill had shown the depth of the glacial drift to be more than 60 feet. A test-pit near the location of the proposed shaft had struck, at a depth of 20 feet, an amount of water which a 200gallon pump was unable to lower. At the Aragon, a few years before, a shaft had been sunk to hard pan with great difficulty and many delays by the usual method of driving laths. Under the conditions it was decided to sink a caisson- or dropshaft. Two 40-horse-power boilers, a Lidgerwood engine with 4foot drum, and a good derrick were set up; and two No. 10 Kuowles

Jan 1, 1892

By W. H. Chang

The phase identification results on several Mg-base alloys are presented. These results have been correlated with strength data and microstructural studies to indicate that carbide dispersion may contribute significantly to raising the recrystallization temperature and strength of Mo alloys. Evidence is presented to show that the degree of carbide dispersion, and hence the extent of strengthening, is governed by the "metal/carbon" ratio which, in turn, depends on both the carbon content and the presence of stable -carbide-forming alloying elements. IN recent years, Mo-base alloys containing small additions of C, Ti, and/or Zr have been developed, which exhibit much higher recrystallization temperature and strength than those of unalloyed Mo. The superiority of these alloys undoubtedly results from simultaneous operation of more than one strengthening mechanism. In the present paper, the strengthening effect of carbide dispersion will be discussed. Although the role of carbide dispersion is being increasingly recognized, the nature of the carbides has, to the author's knowledge, not been well es- tablished. In Table I are presented some of the phase identification results on representative Mo alloys. These results have been obtained by X-ray diffraction of residues electrolytically extracted from an ethyl alcohol solution containing 7 pct HC1.

Jan 1, 1961

By Bennett Bates

NOWHERE in the world has cone classification in closed-circuit grinding with tube mills reached as high a state of development as on the Witwatersrand. In the development of the Far East section the necessity of fine grinding to obtain. satisfactory residues gave rise to a situation with which the cone could cope only at a great sacrifice in efficiency of tube-mill grinding. H., A. White1 recognized the limitation of the cone in his study of the theory of tube milling as early as 1915, but it was not until Ewing, Davis and. Willey2 carried out their tests at Springs Mines during 1920 that the advantages of mechanical classifiers' were demonstrated. During the fall of 1924 the writer supervised a series of tests with Dorr classifiers undertaken by Mr. White, Consulting Metallurgist, at the mill of the Geduld Proprietary Mines, Ltd., Dersley, Transvaal (Far East Rand). The importance of classification to obtain efficient tube-mill grinding was thoroughly demonstrated. The installation of classifiers of the above type that followed the test, confirmed the results of the experimental work.

Jan 2, 1926

By L. W. Bahney

FREQUENTLY in using a thermo-electric pyrometer for measuring the temperature of a furnace, a hole is drilled at the back or side of the furnace, through which is introduced the tube containing the thermo-couple. At times the couple is left almost where it drops, for the reason that it soon becomes too hot to be handled easily, and the space at the back or side of the furnace may be so small and uncomfortably hot that an easy and accurate adjustment is nearly impossible. In order to overcome this clumsy and unscientific method of using the thermo-electric pyrometer, I designed an adjustable stand, to hold the clay or quartz tube unclosing the platinum and plati-num-rhodium leads that constitute the couple of the Le Chatelier thermo-electric pyrometer. This stand also allows an easy and rapid adjustment of position to varying heights and angles, as may be desired for special reading. This stand is illustrated in Fig. 1. The couple in the tube might be of better service if the tube were held a little higher above the charge in a roasting-dish, changing the height and angle if desired. The stand, made of 1.5-in, water-pipe and mounted on casters, is heavy enough so it cannot be tipped over easily. It is adjusted to any position, and has a universal clamp which holds the clay or quartz protecting-tube. To avoid disturbing the wires of the couple at the cold junction each time the tube is moved, the cooling-bottle sets in a wire basket so placed that it moves forward or back with the couple. To overcome the necessity of leveling and adjusting a galvanometer at each furnace, a switch-board is used to connect

Jan 1, 1910

By Frank C. Frischknecht

Most early development and application of electromagnetic prospecting methods took place in Scandinavia, where geological conditions favor their use. In other parts of the world these methods have aroused cycles of interest, but in Scandinavia they have been used continuously and successfully since the 1920's. Electromagnetic methods may be classified into two general groups. One group includes methods in which the source of the electromagnetic field remains stationary while the receivers are moved about to explore the area. The other includes procedures in which the energizing and receiving systems are moved together. Other classifications could be based on the size of the energizing source, the particular components of the electromagnetic field which are measured, or the mode of trans- porting the equipment. The difference between fixed-source and moving-source methods, however, is of such great fundamental importance that it will be emphasized in this discussion.

Jan 9, 1959

By Charles E. Wait

In the analysis of a set of interesting furnace-products belonging to the metallurgical cabinet of the School of Mines, I placed in the hands of one of my students a sample of litharge which gave the results quoted below. The collection of specimens from which this was taken, represents the products obtained in the blast-furnace treatment of argentiferous lead ores, also samples from the zinc process, and those from the cupellation of the enriched lead. The sample, when received, was marked "bismuth litharge," and was that obtained during the last stages of cupellation. It gave upon analysis the following : Per cent. Lead,.......85.36 Antimony,.......06 Bismuth ,........20 Copper,.....49 Iron,...... 69 Zinc,......18 Nickel,.....01 Silver,....2.94 Lime,.....36 Magnesia,....03 Silica,.....12 Sulphuric anhydride,. .32 Carbonic anhydride,. 1.25 Water,.....24 Oxygen,..,.7.80 99.95 At present I wish merely to call attention to the large percetage of silver present (equal to 857 ounces Troy per ton of 2000 pounds avoirdupois), and also to note two or three determinations that I have recently made, with a view to ascertain, if possible, the condition in which this silver exists. If I mistake not, it is usually assumed that silver exists in litharge in the metallic state; and it is, indeed, in the analyses of litharge, rarely expressed otherwise. This method of reporting the silver is, no doubt, due to the accepted statements that the oxides of silver are reduced to the metallic state at a temperature of 300' C. or less. The following experiments lead me to believe that silver exists in litharge, not entirely in the metallic state :

Jan 1, 1887

By N. C. Gay, P. J. Van Der Veever

The Klerksdorp gold mining district, South Africa, experiences a relatively high level of seismicity with many seismic events of magnitude greater than 4. These large events appear to have foci close to fault planes, most of which displace the strata by several hundred metres over a wide area. To help understand the mechanism of these large mining- associated seismic events, in situ stress measurements were made at 4 sites using "CSIR doorstopper" strain relief techniques. The sites were chosen close to, or some distance from fault planes and other structures. The results show that at all 4 sites a relatively large horizontal stress is oriented approximately north- west. The magnitude of this stress ranges from 0,78-1,O of the vertical stress. A marked horizontal stress anisotropy, varying from 13-30 MPa is also present. The dominant structural features are large, north-east striking normal faults which extend across the entire length of the goldfield. Displacements across these faults vary from a few centimetres to several hundred metres. Bedding plane faults across which large displacements may occur are also common as are north and north-west striking dykes. The majority of the faults strike at approximately 90º to the maximum horizontal stress and at all sites a large compressive stress plunges in the direction of dip of the strata and fault planes. Thus a significant shear stress may act across suitably oriented planes causing them to be in a state of potentially unstable equilibrium. This abnormal stress situation would exist along the entire length of the fault

Jan 1, 1982

By E. E. Krist, W. H. Sweetser

Sampling of an orebody has a number of purposes. In the initial phase, it is necessary to define the limits of the orebody and mineral content to the extent that it can be stated whether it is, in fact, an economic orebody. Also, samples must be generated so that geological and metallurgical evaluations can be made. Finally, when sufficient information concerning the geology, mineralogy, and metallurgy are known, a mining method and plan can be developed and the metallurgical; plants constructed to process the ores as they become available. With today's large, complex open pit copper mines, single sampling methods would be inadequate. Diamond drilling, percussion drilling, underground shafts and drifts all play a part in the total orebody, definition. At Anamax Mining Company's Twin Buttes mine, sampling and orebody definition.wil1 eventually lead to the existence of three metallurgical processing plants and, perhaps, an underground mining operation. A 30 000 tons per day sulfide concentrator was placed in operation in September 1969 and a 10 000 tons per day oxide leaching plant was placed into service in May 1975. The aim of this presentation is to historically discuss the orebody sampling that has been done at Twin Buttes, briefly describe the orebody, and discuss the analytical methods currently used to assist the geologist, metallurgist and mine planner in their respective evaluations.

Jan 1, 1978

By R. W. Balluffi, B. H. Alexander

RELATIVE diffusion rates of copper and zinc in a brass have been measured in a vapor-solid type of couple with which the amounts of copper and zinc diffusing past inert Kirkendall markers can be obtained by means of a few simple experimental measurements. If inert markers are placed on the surface of copper which is then exposed to zinc vapor from a brass chips, the particles become buried due to outward diffusion of the copper, as shown in Fig. 1. A schematic diagram of such a couple after diffusion is shown in Fig. 2. Consideration of the diffusion flow of copper and zinc shows that the entire hatched area, including the cross-hatched area, is proportional to the amount of zinc diffused inward past the markers and that the smaller cross-hatched area is proportional to the amount of copper diffused outward past the markers. These areas are completely determined by the expansion of the couple, the depth of the buried particles below the surface, and the chemical composition at the specimen surface. As Darken1 has shown, the ratio of diffusivities of copper and zinc is then given by the ratio of these two areas. Polycrystalline copper and two copper single-crystals made by the Bridgman method were prepared in the form of 1.5 cm diam disks approximately 0.5 cm thick with faces plane and parallel. Tungsten particles approximately 0.001 cm in diam were bonded to the surface of each disk by heating 5 hr at 1060°C in vacuo. Each specimen was next

Jan 1, 1953

By Bashir Ahmed, Fred D. Wright

Numerous investigators have studied the various factors that influence the ultimate strength of model mine pillars, such as ratio of height-to-least width; restraint or friction on the top and bottom; 1,2 the effect of stress distribution in pillars on their strength;3 and the scaling factors involved in applying the results of model pillars to full-scale pillars. However, the load-bearing capacity of pillars after initial failure does not appear to have been investigated. Yet many mines employ methods in which small pillars or pillar remnants are left systematically; these pillars crush as mining progresses and, of necessity, affect the behavior of surrounding rock even after initial failure. The effect of such crushed or crushing pillars depends largely on their load-deformation characteristics. This chapter presents the results of a preliminary investigation to determine the load-deformation characteristics of a few model mine pillars to and beyond initial failure. Various investigators have also studied the elastic and viscoelastic behavior of mine structures. In such studies, computers are frequently employed to obtain numerical results by the finite difference or finite element methods. It would be entirely feasible to write a program that would approximate the load-deformation characteristics of pillars to and beyond the crushing stage if these characteristics were known. More accurate information on the induced stresses and deformations in overlying strata and on surface subsidence could be obtained, information which should result in better strata control by enabling the engineer to calculate more accurately the effects of changes in pillar spacing, size, and shape.

Jan 1, 1972

By Irwin R. Higgins

CONTENTS A. Introduction B. System Description C. Uranium Pilot Plant Programs D. Summary INTRODUCTION The Chem-Seps Continuous Countercurrent Ion Exchange (CCIX) contactor was first conceived of in 1951 at the Oak Ridge National Laboratory. In the 27 years that have passed, there has been a steady stream of pilot plant process development studies on a variety of processes far too numerous to mention. These have been in the area of water and waste treatment, chemical processing, ore leach treatment, and many others. Many successful production systems have been installed and operated in a variety of applications. A few of these are described herein together with a description of the system and its operational characteristics. SYSTEM DESCRIPTION Chem-Seps Continuous Countercurrent Ion Exchange* is a single loop in which various sections are separated by valves to isolate the sections performing different functions simultaneously. (Refer to Figure 1). To explain the working of a typical unit, let us use a simple configuration used in water softening or demineralization. The resin is moved in small increments by the hydraulic ram action. All solution flows are countercurrent to the flow of resin. The contaminants are removed in the process cycle and the resin is moved in the pulse cycle. A controller in the effluent stream from the treatment section senses the proper limit permissible in the effluent. In the process cycle, the influent enters through a set of distributors, moves downward and leaves through a set of collectors. Simultaneously the regenerant enters through valve RE and leaves through valve WA. The rinse enters through valve RI and its duration is controlled by an interface controller. In the process cycle, valves B, C, and D are closed, isolating all the sections. The duration of the process cycle is 4-10 minutes depending on the contaminants to be removed and is controlled either by a timer if the contaminants are fixed, or a controller in the effluent stream, if the contaminants fluctuate at short intervals. Valve A is open and resin is dropped to the pulse section simultaneously with the removal of contaminants in the treatment section, regeneration of loaded resin in the strip section, and rinsing of regenerated resin in the rinse section. As the resin drops through the valve A, it is backwashed to remove the suspended solids or resin fines. Removal of these fine particles is important to avoid the unnecessary pressure drop in the bed and plugging of the distributors. At the end of process cycle, all flows going into the unit and out of unit are automatically shut off. The valve A closes and valves B, C, and D open in proper sequence. A slug of water enters through valve PU, a predetermined incremental volume of resin moves into the regeneration section, an equal volume of regenerated and rinsed resin enters the bottom of the treatment section, and an equal volume of the loaded resin leaves the top of the treatment section and goes into the resin reservoir section. (The resin movement is plug flow with the Reynold's number being in the laminar region of the curve, and no fluidization occurs during the pulse cycle.) The total time required for proper sequencing of valves and the movement of resin is 20-30 seconds. At the end of this period, the valves B, C, and D close and valve A opens. The solution valves open and normal steady state operation begins. All valves are interlocked and properly sequenced. The resin movement is precisely controlled by sonic devices. Special Features of Chem-Seps CIIX "Downflow"*: The raw feed in the treatment section moves downward and the resin moves upward in the treatment section. The "downflow" of feed overcomes the handicap encountered in "upflow" systems. The "upflow" of feed requires a certain minimum flux during process cycle to lift the bed and keep it

Jan 1, 1979

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Jan 2, 1969

RUfUs J. Foster, Scranton, Pa. (communication to the Secretary*) :—In answer to one of the inquiries made of Mr. Conner, and as a matter of historical record, I beg to say that the idea of supporting the strata over worked-out areas in coalmines by flushing the openings full of culm originated and was put into actual practice by the late R. C. Luther, a former member of the Institute, at that time Chief Mining Engineer, and later General Manager, of the Philadelphia & Reading Coal & Iron Co. In the early 80's the Philadelphia & Reading Coal & Iron Co. purchased from Messrs. Hecksher & Co. the Eohinoor colliery, situated in the western part of the borough of Shenan-doah, Pa. On taking possession of the colliery the Philadelphia & Reading Coal & Iron Co. made a conlplete resurvey of the mine-workings, giving an absolutely correct map which showed not only the plan of the mine-workings, but also every improvement on the surface over the workings, and the marked features of the surface of the ground. Tidal elevations were shown at every eurvey-station in the mine and on the surface, so that, as is the case with all the maps of the company, contour-maps of either the surface or the bottom of any coal-seam, or geological cross-sections, could be constructed directly from the information on the mine-maps. In a cornparatively short time after the company took possession of the colliery, the workings which extended under the western portion of the borough of Shenandoah began to cause trouble and damage dwellings and other buildings in that section of the town. The lots in this section had been sold, in many cases, to individuals by the Gilbert & Shaefer Estate, owners of the coal-lands on which the colliery was located. In

Jan 1, 1912

By Adrian M. Crawford

INTRODUCTION A study has been made of the stability of blocks and wedges of rock subjected to gravity forces in the roofs of underground excavations. Rock wedges may become wholly or partly self supporting with the mobilization of shear resistance of discontinuities bounding such wedges. The influence of in-situ stresses and the relative stiffnesses of the intact rock, and shear and normal stiffnesses of the discontinuities has been investigated. A two dimensional, plane strain model of symmetric rock wegdes in a horizontal stress field has been utilized. A comparison between the results of an extension of a closed form solution proposed by Bray(1981), and numerical analyses with Displacement Discontinuity elements (Crouch, 1976), are presented. These analyses indicate that the stability of the wedge and the stress redistribution around the wedge upon excavation of an opening is markedly influenced by the ratio of intact rock stiffness to seam normal and shear stiffness. It is shown that the analytical solution provides a reasonable measure of the lower and upper bounds of the loads necessary to cause failure of the wedge. MODELS The problem considered (Fig. 1) is a two dimensional plane strain model containing two discontinuities. The discontinuities are symmetrically disposed with respect to a horizontal excavation which forms a wedge of rock bounded by these discontinuities. The angle of the intersecting discontinuities at the apex of the wedge is 2[a]. Mechanical properties of the two discontinuities are identical, being represented by linear normal and shear joint stiffnesses Kn and Ks and angle of friction [o]. The rock wedge is loaded by an in-situ horizontal stress field [ah]

Jan 1, 1982