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By H. H. Taft

The mining possibilities of the volcanic area south of Bel-mont, Nye county, Nevada, have long been known. Some of the old-time prospectors knew that gold existed there. Its remoteness from any source of supplies, its long distances from water, the absence of game, and more, perhaps, the lack of grass for animals to subsist upon, has made this an unattractive region in which to search for mines. The decline of the Comstock mines, the exhaustion of sundry large and rich ore-bodies, the high cost of mining, marketing, and, particularly, the ruinously high freight-charges upon refractory ore that had to be shipped to distant smelters, have kept investors out of Nevada for the last few gears; and mining people have hardly yet awakened to the importance of To-nopah, Goldfield, and perhaps the newer and less developed districts. The discovery of Tonopah by J. L. Butler, who located the Mizpah claim in May, 1900, and the fortunes soon realized there, attracted many people. As the boom declined, many went away, some scattering out into the surrounding country, and the population is now about 7,000. In the fall of 1902 a discovery of gold was made 23 miles south, in what is now known as the Sandstorm group, 4 miles NW. of Goldfield. In the winter of 1903—4 the Combination, January and Florence mines were discovered, and shipments of high-grade ore soon followed. In January, 1905, there were 10,000 people in Gold-field. In June, 1904, rich gold-ore was found 85 miles SE., at the foot of the south end of the Kawich mountains, but this discovery was kept quiet until a re-location could be made. On August 10, 1904, the Bullfrog claims, and a month later the Ladd mountain and neighboring claims, were located. The Shoshone group was located September 24. This district is

Jan 1, 1907

By W. R. Finney

THE formation of scale in boilers and other industrial equipment, and the corrosion of such equipment, are closely related problems. Since in the petroleum industry these problems cover a very broad field, this paper has been confined to the effects of scale and corrosion on gas engines, compressors, pipes and fittings, used in plants extracting gasoline from natural gas, and the steps taken in arriving at a workable plan for combating these evils at the Midwest Refining Co.'s plants in the Salt Creek field, Wyoming. Eliminating, or at least minimizing, the many deleterious effects occasioned by the use of bad water in jackets and cooling systems of gas engines and compressors has been the subject of much study for many years but no generally accepted plan has been evolved. The problem was unusually difficult at Salt Creek, as the severe winters of Wyoming bring operating conditions quite different from those encountered in warmer states, and the water available was especially bad. While the conditioning of water to prevent scale and to lessen corrosion may not be a particularly difficult problem in plants in large industrial centers, it becomes much more difficult when attempted at plants remote from railroads and by men without previous experience to guide them. In fact this difficulty has been so great in the Wyoming oil fields that until comparatively recently it has been the practice to allow much equipment to be ruined rather than to attempt corrective measures. At the Midwest plants this problem was given attention first by the plant men and later by both plant men and laboratory staff. To the latter it was simply one of many problems which arise in connection with field and plant operations, which must be studied and, if possible, solved. Many mistakes were made during the course of this investigation, but since mistakes, properly interpreted, are of value in guiding one's steps aright, it is believed that a review of the different stages of development which have led up to the present method of handling this problem will prove of interest to the industry.

Jan 12, 1926

By Cadwallader Evans

THE American Institute of Mining Engineers was organized in the anthracite region of Pennsylvania by men who were primarily interested in anthracite. Its first meeting, at Wilkes-Barre, Pa., in the Northern Anthracite field, on May 16, 1871, resulted from a call sent out by three outstanding men of the anthracite .industry: Eckley B. Coxe, R. P. Rothwell, and Martin Coryell. The best known of these was Eckley B. Coxe, who was the manager of large hold¬ings operated by him and his family,. and who is remembered as the inventor of a special grate for burning very fine anthracite, known as the Coxe traveling grate, which is still very widely used. R. P. Rothwell was a well-known consulting engineer of the region, as was Martin Coryell, who was associated with another well-known anthracite family, the Pardees. There is no record of the discussions that resulted in this initial meeting, but it is safe to assume that the formation of the Institute was largely influenced, through appreciation by the founders, of the necessity for a free exchange of information covering the whole of the mining industry. One of the rules adopted at the first meeting was:

Jan 1, 1947

By J. N. Chew, C. A. Connally

A correlation is presented for predicting the viscosity of gas-saturated crude oils under reservoir conditions. It is based on the dead oil viscosity and the solution GOR. The correlation was developed from a study which showed that at a fixed solution GOR, the relation between the gas-saturated oil viscosities and the correrponding dead oil viscosities is a straight line on logarithmic coordinates. Data from 457 crude oil samples from the major producing areas of the U. S., Canada and South America were used. The best straight lines through the data were fitted by the method of least squares with a digital computer. The correlation is presented in the form of an equation and also in a convenient gra-phical form. INTRODUCTION The viscosity of gas-saturated crude oils under reservoir conditions is an important physical property used in reservoir engineering calculations. Many difficulties are inherent in the sampling of gas-saturated oils and in the laboratory measurement of their viscosities. Therefore, it is frequently neither possible nor convenient to obtain measured values, so the viscosity must be estimated from other, more readily available data. This paper presents a correlation for predicting the viscosity of gas-saturated crude oils. The correlation is based on the amount of gas in solution and the viscosity of the dead oil at the temperature of interest. A previous correlation of these variables was presented by Beal. In comparison, the correlation presented here extends to a higher GOR and to a lower dead oil viscosity. Over the range of variables covered by both, this correlation is based on approximately 11 times as many oil samples. DEVELOPMENT OF CORRELATION A study was made of the variables or parameters which could be used to relate the viscosity of a gas-saturated oil to its dead oil viscosity. Preference was given to those variables which are easily and commonly measured in the field or in the laboratory. It was found that either the differential liquid formation volume factor or the solution GOR of the gas-saturated oil could be used as a correlating parameter. The solution GOR was se- lected for the correlation because of its simplicity and availability. In an attempt to refine the correlation by introducing a second parameter, the following additional variables were tested: differential liquid formation volume factor at the reservoir bubble point, the formation volume factor at the saturation pressure for the GOR of interest, reservoir temperature, viscosity of C+ fraction at 100°F and atmospheric pressure, weighted average gravity of gas in solution, oil gravity, reservoir bubble point pressure, saturation pressure at the selected GOR and reservoir temperature, and gas mol fraction. None of these improved the correlation to any significant extent. It was found that at any fixed solution GOR, the relation between the gas-saturated oil viscosities and the corresponding dead oil viscosities is a straight line on logarithmic coordinates, for the range of variables investigated. This straight-line relationship was used for the correlation. Viscosity data on a total of 457 crude oil samples were used. The data were obtained with rolling ball-type viscometers. The samples came from all of the important producing areas of the U. S., as well as from Canada and South America. Their geographical distribution is shown in Table 1. The ranges of properties represented by these samples are as follows: For each crude oil sample the viscosity of the liquid phase from each step of a differential liberation was plotted against its solution GOR on semi-logarithmic paper. A smooth curve was drawn through the points and values of viscosity in centipoises were read from

Jan 7, 1951

By Luis N. Henriquez

One form of encouragement for the small copper mining sector in Chile has been the construction and management of custom mill facilities to process the ore. The paper describes an economic analysis framework for the evaluation of government custom milling opportunities. Feasible mill locations and capacities within a region are selected and the infrastructure and milling costs associated with each combination of location and capacity are assessed. For each combination, the economics of developing and operating known copper deposits in the region is evaluated, and an optimum cut-off grade and mine capacity is selected for the deposits which justify development. Since the total ore supply from mines in the region may exceed a particular custom mill capacity, mine development is scheduled to optimize the economics of the mill facility. Finally, the best custom mill location and capacity is selected on the basis of overall costs and benefits. A copper mining region in northern Chile is used to illustrate the application of the model. A mobile mill approach is examined and compared with the fixed location mill alternatives. Results are analyzed as a function of copper price.

Jan 1, 1977

By R. H. Thorpe

Longwall working in Britain developed to overcome problems arising from depth of seams causing roof and ventilation difficulties. This system became very widespread particularly in the thicker seams, where faces of up to one mile in length were not uncommon. In the thinner sections, in order to remain competitive, the longwall undercutting machine was developed. Following the development of the coal cutter, every other aspect of the face operation was examined and mechanized as it became a bottleneck to output and efficiency. The face system itself was modified and workings concentrated with the same objectives.

Jan 1, 1977

Jan 1, 1938

By J. C. Febles

HISTORY. THE use of iron for the precipitation of copper was known at least as early as the fifteenth century. Both Paracelsus and Basil Valentine refer to it in their writings, as early as 1500 A. D. It was used in Peru, for this purpose prior to 1637, and at Rio Tinto, Spain, as early as the sixteenth century. The statement has been made repeatedly that in the early history of the mining industry at Butte, the practicability of this method of recovering copper from solution was overlooked, and that enormous quantities of copper-bearing water were allowed to go to waste, the copper in which might easily have been recovered at small cost; and that this oversight on the part of the mine operators was due to ignorance of this method of recovering copper. As a matter of fact, very little copper-bearing mineral was encountered in the mines of Butte until a depth of 400 or 500 ft. bad been reached, and in many cases much greater depths were necessary to reach the copper-bearing zone. The water encountered in the upper levels (although in most cases quite highly mineralized) contained little or no copper, and it was only after considerable areas of copper-bearing ore had been uncovered and developed that copper sulphate began to. appear in the mine water in any considerable quantity. In fact, the first water that was observed to contain copper carried it in such small amounts as to be of little or no importance. It was only after years of underground work had opened extensive areas of stopes, drifts, and other underground workings, these being subsequently filled with waste, nearly all of which contained small copper values, which became oxidized by exposure to the air and were acted upon by the slowly percolating mineral water, that the recovery of copper from mine water became commercially important.

Jan 7, 1913

By B. Woyski

Many writers, in discussing defects caused by oxidation and gassing of bronzes and red brasses advocate substantially the same cure for both. But from its nature, oxidation cannot take place if there is an excess of fuel in the furnace, while the gases absorbed by some alloys are products of incomplete combustion of the fuel. Hence the metal can be either oxidized or gassed, but it is doubtful whether these actions can take place simultaneously. Oxidation can be easily overcome by the use of deosidizers or it may be avoided by protecting the molten metal with suitable fluxes. Absorption of gascs is more difficult to overcome: the regulation of the air and fuel, so as to produce complete combustion, and the protection of the bath by mineral fluxes arc the most important factors. Gas expulsion, resulting in gas holes, porosity, unsoundness, and swollen or cauliflower-headed risers, is said to have several causes. One writer1 lists the most common causes in the order of their importance, as follows: Superheated metal, dirty or slaggy furnace conditions, using metals low in quality or those previously subjected to bad melting practice, poor grade of fuel, use of newly lined or damp ladles, indiscriminate mixing of scrap or illogical combinations of metal. Superheating the metal usually occurs when the heat is ready to be poured but for some reason must be held in the furnace. In this case, a careful furnace tender tries to avoid overheating the metal by keeping a mild fire; that is, a reducing fire which, unfortunately, results in gassing the metal. A dirty, slaggy furnace may result in gassing the metal by retarding the heating and prolonging the time necessary to bring the metal to the proper temperature, thereby increasing the chances of gassing in uncertain furnace atmosphere. It is doubtful whether rnetals of low quality have anything to do with gassing molten metal, except, possibly in the case of metals containing

Jan 1, 1923

By B. Woyski

Many writers, in discussing defects caused by oxidation and gassing of bronzes and red brasses advocate substantially the same cure for both. But from its nature, oxidation cannot take place if there is an excess of fuel in the furnace, while the gases absorbed by some alloys are products of incomplete combustion of the fuel. Hence the metal can be either oxidized or gassed, but it is doubtful whether these actions can take place simultaneously. Oxidation can be easily overcome by the use of deosidizers or it may be avoided by protecting the molten metal with suitable fluxes. Absorption of gascs is more difficult to overcome: the regulation of the air and fuel, so as to produce complete combustion, and the protection of the bath by mineral fluxes arc the most important factors. Gas expulsion, resulting in gas holes, porosity, unsoundness, and swollen or cauliflower-headed risers, is said to have several causes. One writer1 lists the most common causes in the order of their importance, as follows: Superheated metal, dirty or slaggy furnace conditions, using metals low in quality or those previously subjected to bad melting practice, poor grade of fuel, use of newly lined or damp ladles, indiscriminate mixing of scrap or illogical combinations of metal. Superheating the metal usually occurs when the heat is ready to be poured but for some reason must be held in the furnace. In this case, a careful furnace tender tries to avoid overheating the metal by keeping a mild fire; that is, a reducing fire which, unfortunately, results in gassing the metal. A dirty, slaggy furnace may result in gassing the metal by retarding the heating and prolonging the time necessary to bring the metal to the proper temperature, thereby increasing the chances of gassing in uncertain furnace atmosphere. It is doubtful whether rnetals of low quality have anything to do with gassing molten metal, except, possibly in the case of metals containing

Jan 1, 1923

By D. Harrington

ONE of the main functions of the United States Bureau of Mines is to obtain and disseminate information that will promote safety in and around mines, and the health and safety of employees engaged in mining. Serious health and safety conditions arising out' of contamination of air in metal mines by dust, fumes from explosives and fires, and absorption of oxygen by timber and other causes, led the Bureau of Mines to cooperate with the United States Public Health Service in the study of dust occurrence and ventilation in metal mines in various parts of the country. Dr. A. J. Lanza, of the U. S. Public Health Service, and Edwin Higgins, mining engineer of the U. S. Bureau of Mines, in 1915, made a detailed study in the mines around Joplin, Mo., their reports1 are now available. In 1916, 1917, and 1918, a similar study was made in the Butte, Mont., region by Doctor Lanza and D. Harrington, mining engineer of the Bureau of Mines; the reports of this investigation will be available soon. In 1919, the study was continued in some of the Arizona mines by D. Harrington, of the Bureau of Mines, and G. E. McElroy and Dr. R. A. Koronski, of the U. S. Public Health Service, the underground work being completed in June, 1920; these reports are now being prepared for publication. In the spring of 1920, the scope of the work was extended, with D. Harrington in charge as supervising mining engineer, and short studies made in the mines of the Coeur d' Alenes in Idaho and around Oatman, Ariz. It is hoped soon to extend the work into mines of California, Nevada, Colorado, Michigan, and Minnesota, and ultimately to other states should the mining companies be willing to cooperate.

Jan 2, 1921

By R. J. Franklin, G. W. Beckman, D. Warren, E. Both, J. F. Libsch

BINARY and ternary alloys of iron, nickel and cobalt respond to annealing in a magnetic field by a characteristic change in the shape of their hysteresis 100p.l,2 An increase in retentivity and a decrease in coercive force produced by the magnetic treatment cause the hysteresis loop to approach the appearance of a rectangle. Materials with a rectangular hysteresis loop have made possible the contact-rectifier³ and have greatly improved the performance of pulse transformers4 and magnetic amplifiers." In the best material presently available for these applications, a 50 pct nickel-iron alloy," the desired characteristics are achieved by aligning the preferred crystallographic directions of magnetization along the rolling direction of the tape. The objective of the present study has been to produce rectangular hysteresis characteristics in materials with inherently high saturation. Iron-cobalt alloys, exhibiting saturation values up to 24,000 gausses' appeared to offer promise for the magnetic annealing technique, because they remain magnetic to very high temperatures,8 exhibit favorable magnetostriction properties: and show zero crystal energy at 42 pct cobalt.10 Among the ternary iron-cobalt-nickel alloys,7,11 response to heat treatment in a magnetic field is unfortunately limited to alloys having rather low saturation values.' It appeared interesting nevertheless, to study a series of compositions connecting the optimum composition (50/50) of the binary iron-cobalt system with the "Perminvar" composition (30 pct Fe, 25 pct Co, and 45 pct Ni). Very recently, R. Smoluchowski and R. W. Turner," have shown that under certain circumstances magnetic annealing can produce oriented recrystallization. A combination of this technique with the domain orientation utilized in the present study might well result in further improvements. The advantages of the powder metallurgy technique in preparing magnetic alloys for study have

Jan 1, 1951

By E. H. Tenney

A discussion of the probable future use of coal for power development involves the study of several basic factors, such as future demand for power, the quantity and availability of fuels in direct competition with coal, the price of coal, and a closely related factor—the efficiency and cost of fuel utilization. Predictions based on purely statistical analyses of past coal consumption have definite limitations. For example, statistics showing the relation between coal utilization and total energy consumption from all sources between the years 1890 to 1930 indicate that during that period the energy consumption per person in the United States increased five times, while the coal consumption per person increased only twice1, and there has been an actual decrease in per capita coal consumption since 1920. Figures such as these, compiled by authentic agencies, emphasize the need for caution in attempting estimates as to the future use of coal, and, incidentally, would seem to offer little basis for optimism in the coal industry. They also suggest the value of analyzing broadly the part played in the past by the related factors of power consumption, competitive fuels, coal prices and the efficiency of utilization. Proper weight must also be given in such a study to the present status and limitations of power-plant developments, arid to the question of what the coal industry itself can do to further its own interests arid influence the consumption of its product.

Jan 1, 1936

By E. H. Tenney

A discussion of the probable future use of coal for power development involves the study of several basic factors, such as future demand for power, the quantity and availability of fuels in direct competition with coal, the price of coal, and a closely related factor—the efficiency and cost of fuel utilization. Predictions based on purely statistical analyses of past coal consumption have definite limitations. For example, statistics showing the relation between coal utilization and total energy consumption from all sources between the years 1890 to 1930 indicate that during that period the energy consumption per person in the United States increased five times, while the coal consumption per person increased only twice1, and there has been an actual decrease in per capita coal consumption since 1920. Figures such as these, compiled by authentic agencies, emphasize the need for caution in attempting estimates as to the future use of coal, and, incidentally, would seem to offer little basis for optimism in the coal industry. They also suggest the value of analyzing broadly the part played in the past by the related factors of power consumption, competitive fuels, coal prices and the efficiency of utilization. Proper weight must also be given in such a study to the present status and limitations of power-plant developments, arid to the question of what the coal industry itself can do to further its own interests arid influence the consumption of its product.

Jan 1, 1936

By Hsun Hu

The formation of annealing textures in high-purity silver, from the various rolling textures obtanled in the course of texture transition, was studied. It was found that from a brass-type rolling texture the recrystallization texture is mainly (120) [211] type, which is quite different from the recrystallization texture of brass. From a predominantly copper-type rolling texture, the reclystallization texture is mainly (100) [001]. The recrystallization texture of silver- varies also with the degree of purity. In each case, however, the reorientation can be expressed as [Ill] rotations of 30° to 40°, which is consistent with the oriented growth theory of the formation of annealing textures. ThE recrystallization textures of rolled silver were studied long ago by Glocker and co-workers (1924-27) and were reported to be (113) [iil] upon annealing at low temperatures.1 Since that time, no further study of the recrystallization textures of silver, particularly with the modern techniques of quantitative texture determinations, has been reported in the literature. In a previous study2y3 it was found that the rolling texture of high-purity silver (99.999 +pct pure) is changed gradually from the common silver- or brass-type to the copper-type by raising the temperature of rolling from 0" to 200°C. The formation of annealing textures from the various rolling textures in the same material is, therefore, of considerable interest. The present paper constitutes the results of such a study. MATERIAL AND METHOD Specimens were taken from the same strips of high-purity silver* that were used previously for

Jan 1, 1962

Energy conservation has been the keyword in many plant expansions. Far many years, most of the phosphate industry has been dry grinding their phosphate rock. Agrico Chemical in Florida has recently been evaluating the wet grinding of phosphate rock, a process which eliminates a pre-dry stage for mill feed while allowing higher through- puts. This same company also plans to open a new phosphate facility in Louisiana that will use wet grinding in both ball mills. The Eveleth Expansion Co.'s Fairlane concentrator will have the largest rod and ball mills in the US mining industry. The plant will consist of three lines, each with one rod mill and one ball mill, and will process 464 ltph. The rod mills will be 15 x 20% ft, drawing 2035 hp. The ball mills will be 17 x 41½ ft, drawing 6900 hp and driven by dual 3000- hp motors. The plant is scheduled for startup in the fall of 1976.

Jan 2, 1975

By Edward Sampson, Allan B. Griggs

SURVEYING of many holes drilled by the U. S. Bureau of Mines in the Metaline district has shown surprising deviations. The holes start in the Ledbetter slate (Ordovician) and pass into the underlying gently dipping Metaline limestone (Cambrian) at varying depths, locally in excess of 1000 ft. All holes start vertical, but one had deflected as much as 35° at a depth of only 300 ft. One hole was found to be deflected 70° at a depth of 1000 ft. These deviations were not indicated to the drillers by any action of the rods or machines. Analysis of the survey data in the light of the observed geology indicates that the holes deviate most in the Ledbetter slate and scarcely at all in the Metaline limestone. The upper part of the "limestone"' in most holes is a massive rock strongly altered by hydrothermal action and essentially homogeneous. The slate is only obscurely bedded but has a cleavage, varying from slight to strong, which is unrelated to bedding. Drill holes have deflected to become nearly perpendicular to the cleavage. Several plans and cross sections are submitted showing the behavior of various holes.

Jan 1, 1946

By Anwar-ul Karim

In one of our recent papers, Cheng, Karim, Langdon, and Dom1 analyzed the creep mechanisms in a Fe-4 pct Si alloy. The experimental results of apparent ac-

Jan 1, 1970

By Paul T. Allsman

1.1-1. Current Status. The history of surface mining is essentially that of mining coal, copper, and iron ores, and the nonmetallic minerals--clays, gypsum, phosphate rock, sand, gravel, and stone. Table 1.1-1 is a comparison of the estimated world production of crude metallic and nonmetallic ores and coal with that of the United States for 1964, in short tons. It includes an estimate of the quantity produced by surface mining methods. Two-thirds of the 8.8 billion tons are mined from surface, ranging from a third of the coal, half the metallic ores, and nearly all clays, stone, sand, and gravel. In the United States, production by surface methods parallels that of the world with two major exceptions: 74% of copper ore and 90% of usable iron ore are mined from the surface, whereas outside the country less than 40% of copper ore and only 50% of usable iron ore are mined from the surface. In surface mining of both metallic ores and coal, much waste is stripped, but in mining nonmetallics the ratio between waste and ore is small. Assuming that the stripping ratio for surface mining in the United States will apply equally to world production, it is estimated on a weighted basis that over 21 billion tons of waste, or a total of nearly 27 billion short tons of material, are mined annually in the world by surface methods. Data are not available to confirm the assumption for waste stripping outside the U.S., but the estimate expresses an order of magnitude that is worth noting. Table 1.1-2 shows the materials-crude ore, coal, and waste-mined by surface methods and the relation to total mined by both surface and under- ground methods in the United States during 1964. Eighty-two percent of all crude metallic and nonmetallic ores and coal was mined from the sur- face, including 82% of metallic, 96% of nonmetallic ores, and 35% of coal. Copper and iron ore comprise 83% of the metallic ores mined from the surface, and clays, gypsum, phosphate rock, sand, gravel, and stone

Jan 1, 1968