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Jan 1, 1891

I TOLD you before that four things are necessary in addition to good judgment for one who wishes to practice the art of casting well. The first is to make the moulds and to have the furnace well made, the wood of a good kind, dry and seasoned, and the material disposed to melt. I have given you enlightenment on all these in detail, and on the last point as well, as you can see in the discussion on the alloys of metals where, among other things, I told you a good deal about those of copper. Therefore I wish to say but little about them in this chapter, but in order to follow the order promised you, I tell you that when you can, and if the labor or expense does not displease you, you should always alloy the whole quantity of the metals that you wish to put into one work and should make them into cakes of one kind. For, in addition to being more conveniently arranged in the furnace and mire easily handled, they all melt at one time and with much less work than they would if they were in pieces of different kinds. It is necessary to give corruption to copper, for if you decided to melt fine copper by itself in a reverberatory furnace your soul would burst before you had any honor therefrom. Then, if you wished to cast a fine thing from it, it would not succeed because it is dot fluid, on account of its viscosity; and if it should succeed, it would be all full of holes, like a

Jan 1, 1942

By H. S. Wang, Y. P. Gupta

Diffusion of zinc and germanium in liquid silver is measured in the temperature range 975" to 1400°C by use of the capillary-reservoir technique. The ex-perinzental results are discussed in terms of the fluctuation and the "hole" theories of liquid diffusion, assunzing the solute as a point charge equal to the difference in the valences of the solute and solvent atoms. The additional coulombic interaction term due to the excess solute charge is evaluated in terms of the Thomas-Fenni approximation. The theoretical and experimental results agree with both the fluctuation and "hole" theories of liquid diffusion. No perceptible effect on solute diffusion in liquid silver of the size difference between the solute and solvent atoms/ions is apparent. DIFFUSION in liquid silver of electropositive solutes indium, tin, antimony, and homovalent gold has been previously reported by Leak and Swalin1 and Gupta,' respectively. These solutes have nearly the same atomic size but differ principally from one another in excess valence (+2, +3, +4, respectively). The observed differences in the temperature dependence and the rate of solute diffusion were explained in terms of an added coulombic interaction between the solute and the solvent atoms. In the case of diffusion of gold in liquid silver, the data were found to be consistent with an effective valence for gold of -0.85, as proposed by Le Claire.3 Recently, Wang and Gupta4 have reported a study of diffusion of ruthenium, iron, and cobalt in liquid silver. The results of diffusion of these solutes and their temperature dependence were found consistent with the hole theories and the fluctuation theories of liquid diffusion, if ruthenium, iron, and cobalt were diffusing in liquid silver with relative valences -2, -1.3, and -0.5, respectively, instead of -3, -3, and -2 as suggested by the relative position of these elements in the Periodic Table of Elements. Furthermore, the predicted valences for these solutes were observed to be consistent with the sparsely available information on the magnetic properties of some of the dilute alloys of copper and silver with these solutes. In theoretical calculations of solute diffusivity, the solute was assumed as a point excess charge equal to the difference in the valences of the solute and solvent atoms. Both the assumption of a point excess solute charge and the use of the Thomas-Fermi approximation to calculate the potential of a solute charge are less precise for the case of electronegative solutes. Therefore, it was not possible to infer from the data on ruthenium, iron, and cobalt an effect, if any, on solute diffusion of the relative differences in either the Period or the size of the solute and solvent atoms or the solute atoms themselves. A study of the diffusion of Period 4 elements, specifically zinc and germanium was, therefore, undertaken since zinc and germanium, respectively, have relative valences of +1 and +3 in liquid silver and the data obtained on diffusion of these solutes could be compared with the available data on diffusion of Period 5 electropositive solutes, indium, tin, and antimony in liquid silver. From such a comparison, it was hoped to learn something about the effect, if any, of the ion size or the structure of the ion core on impurity diffusion in liquid silver. EXPERIMENT The diffusion of tracer zinc and germanium in liquid silver was studied by the capillary reservoir technique, modified adequately for use at high temperatures. In principle, capillaries containing liquid silver

Jan 1, 1970

By W. W. Yankie, A. T. Chatas

This paper is written as a discussion of the paper, "Buckling of Tubing in Pumping Wells, Its Effects and Means for Controlling It" by Arthur Lubinski and K. A. Blenkarn, which war published in the March, 1957, issue of Journal oP Petroleum Technology. An analogy is drawn between the buckling of tubing in pumping wells and a fiube, fitted with frictionless pistom, linked by an inelastic rod, and which is subject to an internal pressure. A simple derivation shows that the critical internal pressure exerts a hydrostatic force on the pisfon which is close to the Euler load for compression buckling of the same tube. While the results agree with those of Ref. I, the basis of calculations has been changed and clarified. The presence of internal upsets at the pistons is discussed. INTRODUCTION In the Appendix, Lubinski and Blenkarn state that a tube with ends closed by frietionless pistons connected by an inelastic rod (Fig. 1) will behave as a column loaded with a force equal to the tension force in the rod. They note that, while the fluid may not resist a shear force, the moment in every cross section is piston force multiplied by the elastic line deflection (c.f., the loaded column). Since the equations of the elastic lines are similar in the two cases, the solution is carried over from the loaded column. On the contrary it is suggested that while the method of solution remains unchanged from the column case, the actual stress distribution is different, a fact which is taken into account in this note. A simple method of approximating the buckling pressure is given, and their reasoning in our mathematical language is continued. GENERAL EQUATIONS The equation of an elastic line, initially straight in the x direction (Fig. 2), is given by In the case of a loaded column, this may be written: For the pressurized tube it was shown, by analogy with the loaded column, that tion has a solution that, for P, = EI/P, any deflection is stable (a criterion for buckling). An attempt will be made to describe more precisely, the forces acting on the tube, and to analyze the buckling condi,tions. DISCUSSION If the tube assumed a deflected position, the volume between the pistons would increase so that in deflecting, the energy of the fluid would decrease. When the increase in elastic energy of the tube (due to bending) is equal to the decrease of fluid pressure energy, buckling conditions exist. Analyzing the forces on the tube (Fig. 3), two transverse forces, T,, T,, exerted by the pistons, are balanced by a resultant of the pressure elements which are linearly dependent on the local curvature of the elastic line (Fig. 4). Unlike most buckling cases, the forces depend on the shape of the elastic line, a condition that makes a rigorous mathematical treatment difficult. Several approximations may be used to clarify the problem.

In-pit crushing systems have been known in the mining industry for many decades. The question whether in-pit crushing is a viable option has often been asked. More than 200 mobile and semi mobile crushing systems have been installed worldwide at various locations and applications. Economic pressures have forced mine operators to reconsider the use of a conventional truck-shovel operation and have contributed enormously to the development of in-pit crushing and conveying systems. The in-pit crushing concepts have varying mobility capabilities. These range from fixed, stationary crushing plants to semi-mobile and fully mobile crushing plants. All these systems are operated in connection with a conveying system. In general in-pit crushing systems have technical and economical cost advantages over truck-shovel operation, particularly as mine capacities increase and mines become deeper. The integration of an in-pit crushing system represents a significant up-front capital investment and the mine is only able to depreciate the capital investment over a sufficient mine life including plant capacity to realise the benefit of the much lower operating cost.

Jan 1, 2003

By S. E. Phillipson

Underground mine mapping is a critical component of understanding the controls on ground instability. Many relatively localized examples of ground failure are associated with geologic features, such as faults, joints, compaction zones, or sedimentological transition zones. In contrast, long-running, directional roof falls are associated with regionally directed horizontal stress fields, which are induced by tectonic plate interactions in the earth?s crust. When stress-related features are distinguished from geological features, underground mapping can be an effective method for inferring the direction of horizontal stress at individual mines. Comparisons with data compiled in the World Stress Map confirm that underground mapping can be a valid method for determining the orientation of maximum principal horizontal stress at a variety of scales, ranging from individual mines to an entire mining district or coal basin. Comparisons are presented between the maximum horizontal stress directions inferred by MSHA?s Roof Control Division through underground mapping and the azimuths of maximum horizontal stress in the World Stress Map database for North America?s Pennsylvanian-aged Appalachian, Illinois, Black Warrior, and Arkoma Basin coal fields. The comparison indicates that azimuths are similar for both data sets, even where variations in the direction of horizontal stress are present. It is interpreted that inconsistencies in direction are attributable to near-surface affects such as deeply incised stream valleys, or to fault zones that represent heterogeneities in the crust.

Jan 1, 2009

By Thomas Fraser, David R. Mitchell

THE primary purpose of the loading plant is to transfer the finished product from the preparation machines to the railroad car, truck, or barge in which it is to go to market. Secondary purposes of the loading plant are: to prevent excessive degradation of sizes during loading, to reduce segregation as much as possible, and to prevent excessive quantities of very good or off-grade coal from entering any one car. Nonuniformity of consignments is one of the chief sources of com- plaints by consumers and coal merchants. A properly designed loading plant will do much to reduce complaints and ensure uniformity, not only from shipment to shipment but also in each individual consignment along the length of the car and in cross section. DEGRADATION IN STORAGE, LOADING AND SHIPMENT The object in loading is not only to handle the coal without breakage and segregation, but also to produce a well-trimmed load that will ride to its destination without spillage or breakage en route. The small sizes present in a car of prepared coal as received by the purchaser consist of: missed small sizes not screened out in the preparation plant, breakage during loading, and breakage caused by handling en route. For domestic sizes of anthracite shipped from the Pennsylvania anthracite field to Atlantic coast cities, the dealers' loss because of break- age in loading and shipment amounts to from 2 to 5 per cent and for anthracite shipped to Middle West cities, the loss is 8 to 9 per cent. This difference is in part because dealers in the Middle West rescreen their coal more thoroughly than is usual in the East. One dealer handling Illinois No. 6 coal shipped from southern Illinois mines to Chicago reports an average size loss of 10 per cent when lump coal is unloaded with a fork. This runs as low as 5 per cent for carefully loaded coal and as high as 15 per cent for carelessly loaded coal.

Jan 1, 1943

By Agustín Arias

El presente artículo describe la historia, geología, explotación, energía eléctrica, metalurgia, planta de flotación de la Compañía minera Atacocha. Dicha compañía fue fundada en 1936 y debido al éxito de sus operaciones, la empresa aumentó su capital, duplicándose la capacidad original de la planta hidro-eléctrica, así como la disponibilidad de aire comprimido. Posteriormente, se ejecutó un plan de ampliación de facilidades de explotación y tratamiento. Finalmente, a partir de 1953 empieza a funcionar la nueva Central Hidroeléctrica de Chaprín -en tanto se espera que en el futuro, las f'acilidades de la Compañía miinera Atacocha sean ampliadas hasta alcanzar en la planta de flotación un capacidad de 1,000 toneladas diarias.

Feb 1, 1953

By E. Escobar

Jan 1, 1939

By Jürgen Antrekowitsch, Thomas Griessacher

The recovery of valuable metals from residues like dusts and sludges is nowadays state of the art. Depending on the complex constitution, a recovery of different metals can – in the majority of cases – only be performed with considerable energy input in high temperature processes together with insufficient yields and newly generated residues. Often, the behavior of the dust or sludge in the process during melting or reduction is unknown. In this work, a detailed characterization of selected residues like steel mill filter dusts, cupola furnace dusts and leaching residues is done. The different steps of getting from solid particles into a homogenous liquid phase were investigated. Although high temperature processing leads to high reaction speeds, the complexity of residues keeps the system away from thermodynamic equilibrium. With this research program, some basics are generated to understand smelting and reduction and the gap between thermodynamical calculations and real behavior can be explained.

Jan 1, 2008

By H. G. Stephenson, C. W. Gregory

"This article describes the methods used for pillar extraction in the Wilson Seam at Canmore Mines, Alberta. The Wilson Seam is extremely gassy and varies in thickness between 7 and 30 ft, with an average of 12 ft. The gradient varies from 5 to 30 degrees, with an average of 15 degrees. The seam was developed using Lee Norse miners to form pillars which the company intended to extract using the same machines. Before pillar extraction commenced, an abandoned and inaccessible mine 160 ft above the Wilson had to be drained of 360 million gallons of water. When this was done pillar extraction commenced. Conditions in the mine slowly deteriorated and after 6 months the decision to withdraw the continuous miners was taken. Slusher hoists were installed to replace the continuous miners, with the result that roof conditions and safety steadily improved."

Jan 1, 1972

By W. F. Boericke

NOT the least interesting sights that New York has to offer the visiting mining engineers are the extensive tunnel operations that are being pushed in connection with the subway construction. While a "hard rock" man might feel at home on these jobs, the engineers driving the subway tunnels have necessarily had to encounter some new problems pe-culiar to the largest permanent mining camp in the country. To drive a heading 36 by 18 ft. in hard rock, with a station section to follow 52 by 27 ft. across-and to do it in the midst of a city's traffic-demands engineering skill of a high order. Not the least of the problems overcome by the engineers in charge was to provide adequate ventilation for the men at the face at all times, so that there would be no delay in the work. With a crew of 40 men (32 drill runners and helpers on the machines alone, working two shifts) a hold-up due to inability to get back promptly to the face after shooting would affect costs quickly. AIR VITIATED BY EXHAUST FUMES FROM MOTOR TRUCKS A complication not encountered by metal miners, but which the subway engineers had to meet, was pollution of the air in the tunnels by fumes from the exhaust of the motor trucks used to haul away the broken rock. As shown in the cut, motor trucks were constantly em-ployed to remove the heavy tonnage broken as the tun-nels went ahead, amounting, according to R. J. Van Wagner, chief engineer of the Del Balso Construction Co., to 48 cu. yd. per ft. of tunnel advance. As the length of the tunnel under his management was 900 ft., it was essential for the safety of the men that suffi-cient air be introduced to dilute the poisonous fumes so that no ill effects would be felt for the entire distance that the trucks had to travel. The presence of the ex-haust fumes was especially noticeable on foggy days.

Jan 2, 1928

The non-metallic minerals, excluding the construc- tions and fuel materials have for long been the "poor relations" of the Mining Industry of New South Wales. The State is self-sufficient in only a few of the industrial minerals and is almost completely lacking in any of the essential fertilizers. The deficiencies must be met by imports from overseas and interstate and in fact New South Wales imports some quantity of every one of the non-metallics. For the year 1967 the value of non-metallic mineral production amounted to only $9,390,000 or less than 3.5% of the States total of $275,900,000 for all classes of mining and quarrying. In roughly the same period, the 1967-68 financial year, New South Wales imported non- metallic materials, valued at well in excess of $22,000,000 from overseas and over $2,000,000 from interstate sources.

Jan 1, 1969

By David S. Robertson

"IntroductionCanada has been one of the world's leading producers of uranium since atomic energy first became of practical importance in 1942. Indeed, prior to this time, between 1933 and 1940, Canada produced significant amounts of pitchblende, as a source of radium, from the Eldorado Mine at Great Bear Lake*.Uranium was first reported in Canada, however, in the middle of the 19th Century in the vicinity of Theano Point on Lake Superior north of Sault Ste. Marie. In the early 1900s, uranium-bearing minerals were reported in Quebec north of the St. Lawrence River and in pegmatites in Quebec and eastern Ontario. In 1930, G.A. LaBine and E.C. St. Paul visited an occurrence of cobalt reported by the Geological Survey of Canada in 1900, and brought the Eldorado Mine into production in 1933, as noted above, producing, in the main, silver and pitchblende.In 1942, developments in atomic energy were such that the Government of Canada, at the behest of Great Britain and the United States, requested that Eldorado, which had been closed in 1940, be re-opened to produce uranium for the Manhattan Project. In September, 1943, all discoveries of radioactive minerals were reserved to the Crown and their staking by private interests was banned. In January, 1944, the government nationalized Eldorado and formed a Crown corporation, the present Eldorado Nuclear Limited, to take over the assets. That year marked the formal beginning of uranium exploration in Canada.The Period 1944 to 1948In 1944, the Crown Corporation and the Geological Survey of Canada began exploring for uranium deposits, largely in the areas of Great Bear Lake and Lake Athabasca. In that year, A. W. Joliffe of the Survey visited properties on the north shore of Lake Athabasca near Beaverlodge Lake and recommended that Eldorado acquire claims in the area. In 1946, P. St. Louis and E. Laurum, prospectors working for Eldorado, found the pitchblende veinlets that led to the Ace Mine. Shaft sinking began in 1951, and production, through a carbonate leach plant, began in 1953.Continuing drilling on the Eldorado claims led to the Verna ore bodies, some 6,000 feet northeast of Ace, on which shaft sinking started in 1954."

Jan 1, 1986

By R. A. Ritter, J. P. Batycky

A numerical technique has been developed to permit estimating the pressure gradient associated with laminar flow of thixotropic liquids through long Pipelines. For this purpose the pipeline is divided into a number of radial and longitudinal increments within which rheological properties of the fluid may be considered as constant at any time. Then, provided only that the fluid flow curve is defined at every duration of shear, it is possible to predict the instantaneous pressure gradient at any cross-section along the pipeline for each desired flow rate and pipe size. The technique consists of an iterative integration of shear rate to establish the appropriate value of the wall shear stress at each location. Consistency of fluid in the increment is determined by the flow history of that increment, while the radial flow associated with variations in velocity profile is accounted for by adjusting the width and radial position of the increment. A number of pressure profiles, computed at each of several flow rates, provide a convenient basis for pipeline design and pump selection. INTRODUCTION In recent years considerable attention has been given to predicting pressure drop associated with the isothermal laminar flow of time-independent non-Newtonian fluids in pipes and annuli. 6,11,12 The approach generally has been to develop analytical relationships between flow rate and pressure drop based on simple constitutive models which hopefully provide an approximate description of the rheological properties of the fluid. Analytical solutions are highly desirable since the influence of all pertinent parameters can be readily determined. Unfortunately, however, this approach is restricted to simple flow geometries and- frequently leads to erroneous results due to inadequacies in the model. In certain cases a solution may be obtained through applying appropriate numerical techniques.l,14 For example, a digital computer program is available for predicting the velocity profile and pressure drop encountered by any Newtonian or time-independent non-Newtonian fluid flowing under laminar conditions in a cylindrical pipe or annulus.l In this paper the consistency behavior of the fluid need only be described in terms of basic rheological data. Analyzing flow systems involving fluids with time-dependent rheological characteristics is considerably more complicated since substantial changes in consistency may occur because of sustained shear action. This sensitivity to shear frequently persists for several hours. Consequently, variations in pressure drop and/or flow rate resulting from the aging process and addition of unsheared or partially sheared fluid to the system must be considered for purposes of pipeline design. This paper outlines a numerical method for predicting the transient and steady-state laminar flow behavior of a thixotropic liquid in a pipeline of arbitrary length (i.e., at a specified constant flow rate, the instantaneous pressure gradient may be determined at any time after start up and at any location along the pipeline). Several such pressure gradient profiles, computed at several flow rates, may be combined to produce a complete portrait of the system response. This flow portrait provides a reasonable basis for pipeline design and for selecting a suitable pump characteristic. TIME-DEPENDENT RHEOLOGICAL BEHAVIOR The most familiar time-dependent rheological properties are those exhibited by thixotropic liquids. Many of these materials, particularly thixotropic crude oils, generally display an apparent yield stress in that a finite pressure gradient is required to initiate flow. Then, under the influence of sustained shear at a constant shear rate, the consistency systematically decreases to some final limiting value. The shear stress obtained at

By A. C. Johnson, es Hol, E. O. Binyon

"INTRODUCTION AND SUMMARYThe tungsten properties of Lincoln Mines, Inc., and North Tem Flute Mining and Development Co. were first explored by the Bureau of Mines in 1942. Work on the project comprised trenching, sampling, a small amount of road and trail construction, and a small amount of core drilling. From April 13 to December 10, 1944, additional diamond drilling was done by the Bureau of Mines to test the lateral and downward extensions of the various tactite zones along the contact south of the Lincoln mine, including the property of the North Tem Piute Mining & Development Co.Claims leased by the Lincoln Mines, Inc., are in secs. 25 and 36, T. 3 S., R. 56 E.; secs. 30 and 31, T. 3 S., R. 57 E.: and sec. 1, T. 4 S., R 56 E., M. D. B. & M., in the Tem Piute Mining District, near the north end of the Timpahute Range in west central Lincoln County, Nev. D. B. Fegles is president of Lincoln Mines, Inc. and general offices are in the Wesley Temple Building, Minneapolis, Minn.In June 1945, the Atolia Mining Co. leased the property and purchased the mill and mining equipment from Lincoln Mines, Inc. P. R. Bradley is president of the Atolia Mining Co., whose offices are in the Crocker Building, San Francisco, Calif. This company surrendered the lease on the property on September 30, 1948. The property owners are continuing operations and are now engaged in building a 20-ton mill.The claims of the North Tern Flute Mining & Development Cc. are in sec. 1, T. 4 S., R. 56 E., M. D. B. & M. Merle F. Schofield is president of the company and maintains an office at Hike, Nev. These claims were leased by H. P. Laslett, of the Utah Nevada Mining Co., in 1945 and by the Atolia Mining Co. in 1946. The owners are now doing some exploratory work."

Jan 1, 1950

By C. S. Smith

QUANTITATIVE methods were used to good effect in the earliest days of metallography1-3 but they mysteriously passed into virtual disuse until the important paper4 by Howard and Cohen in 1947. Various devices for the measurements of integrated linear intercepts have been constructed, primarily by petrographers. The hydraulically operated stage designed by the writer5 was satisfactory, but prolonged use caused air bubbles to become entrapped, which introduced back-lash. A new stage has been constructed which avoids this defect and provides better integration when measuring directional structures. This utilizes a circular traverse, and integration is achieved by counting electrical pulses produced by a photocell and a light chopper.* The stage is shown diagramatically in Fig. 1 and in photograph, Fig. 2. It is of simple construction. Mounted on a plate with clamps to fit the stage of a standard metallurgical microscope is a worm and 100-tooth worm gear, the latter supporting the specimen to be measured. The worm is manually actuated by a knob which contains inside it three

Jan 1, 1961

By E. J. Gleim

A study of the records on file in the Bureau of Mines reveals that moray fire in coal mines have been started by electrical equipment or circuits. There the fires were of undetermined origin, electricity often was Strongly suspected as the probable cause. While it is unfortunate that positive evidence as to the cause is so often lost in the general destruction resulting from fires, there are many lessons to be learned from fire s in which the origin was definitely established as electrical. For modern high-speed methods of producing coal, electrically operated machinery has become virtually indispensable underground. With increases in the amount of equipment it has not always been necessary to increase the number of circuits in the mine where direct current is mainly used, but it has been necessary to increase the carrying capacity of these circuits. For example, lends such as heavy-haulage units drawing 1,000 amperes or more have brought boat the introduction of 6/0 and "No. 9 section" trolley wires. This has not made the task of fire prevention any easier, for it has meant that circuit breakers s must be set so high that partial short circuits fail to open them, therefore an arc of considerable proportions can be maintained without causing the, beaker to open. Thus, if as fall of roof brought a trolley wire down against a loaded car of coal, an arc might be struck that would ignite they cowl without opening the circuit breaker.

Jan 1, 1937

Estimation of local recoveries is an important issue in a selective mining operation. Two techniques, probability kriging and multigaussian kriging, are applied to estimate local recoveries at Jerritt Canyon. The pros and cons of each method are discussed in light of the results. Both methods provide simple and satisfactory solutions to the problem of estimating local recoveries. Consequently, they can be useful tools to work with in a selective mining operation.

Jan 1, 1986

There are many inherent risks in creating a mine plan for a new ore zone in an underground mine; one of such risks is the redistribution of stresses that could be a cause of instability. Using numerical modelling tools, it is possible to model the planned stope extraction sequence and evaluate the influence of mining induced stresses on the stability of remnant pillars, and use this information to remedy potential setbacks. This paper demonstrates this approach through a case study of the short-term mine plan of the Lapa mine of Agnico Eagle Mines Ltd., an underground gold mining operation near Val d?Or. Three-dimensional boundary element modelling is used to compute the stresses induced by the stope extraction sequence as planned with a longitudinal retreat mining method. The proposed methodology can be generalized to other mines that require an understanding of the stress concentrations at the pre-feasibility stage of mine design.

May 1, 2009