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The Du Pont Magazine for August and September gives the following interesting information regarding recent progress in the use' of explosives. Blasting -Clay.-"The place where I tried blasting down clay for a brick yard had been worked for some years by old-time pick and shovel method. There was a large shallow pit, irregular in shape, with a perpendicular face at one end. I put down a line of holes 3 ft. deep and 6 ft. back from this face, loading each hole with one and one-half car-tridges of Red Cross Extra 40 per cent. dynamite. The charges were connected up to a blasting machine circuit and fired electrically. "Two of these shots kept the brick yard men very busy for two days taking out the loose clay. "I am convinced that if any brick yard man will try this method he will always have a blasting machine and dynamite on hand thereafter, because it cuts labor cost almost in two to get down the clay in. this way." In some clay pits the practice is to blast a large amount of clay in the fall, allowing it to freeze and thaw through the winter. Such clay is much easier to puddle in the spring than freshly dug or blasted clay. When the clay contains stones, the blasting loosens them and makes their separation-easy. Well-Drill Holes in Quarrying.-The well drill or cable drill method of working a quarry face is now in quite common use. The use of large drills is constantly increasing among quarrymen. In fact the growing tendency is for large machinery of all kinds such as mammoth crushers, steam shovels, etc. Volume is what is wanted nowadays. The advantages of the big drill over the piston driven drill are numerous. By carrying the holes the full depth of the face the stone is loaded and treated on one working floor. It eliminates the cost of bench cleaning. Loading operations are less frequent, thus lessening the danger. Stone can be shot down in greater volume and in better shape, making it economical to use a steam shovel. No bench cleaning makes it safer for the men. It is cheaper and can be used in outlying and temporary operations where the cost of installing a power plant would be out of the question. It permits a greater spacing of bore holes and eliminates the necessity of "squibbing" or springing. In this method usually holes from 4 in. to 6 in. in diameter are drilled the full depth of the face from 15 ft. to 2,0 ft. apart, and as far back and the whole face shot down at one time. The cost of well drilling may vary all the way from 20 cents to 75 cents: per foot, and in extremely hard rocks up to $1.50 per foot.

Jan 10, 1916

By S. G. Malghan, A. L. Mular

Size distribution and surface area measurements play an important role in the characterization of crushed and ground granular materials properties. This paper outlines sampling methods of granular materials followed by a detailed treatment of principles of size and surface area measurements of a wide range of sizes from crushers feed to ball-mill ground sub-micron particles. Currently available equipment for size distribution and surface area analysis is described and critically examined with respect to advantages, range of application and precautions in their use. Equipment for on- stream size analysis is also evaluated. Finally, a list of criteria are given for selection of particles size and surface area measuring devices for a particular application.

Jan 1, 1982

By John F. Blandy

Every new mining district has had its own peculiar experiences in inventing and experimenting upon new methods for the various operations of mining, and more particularly in the processes of crushing and dressing ores. As a matter of course, during this period many old things have been reinvented, patented, and cast aside, there to remain until at a future day other geniuses shall bring them forth again as new. In this respect the Copper Region of Michigan has not been behind other mining centres, and probably in no other part of the country has more money been expended in devising new machines and improvements upon old ones for the crushing of the rock. The appliances for washing the sand have not been so varied, simply for the reason that, having but one mineral, or rather metal, of high specific gravity to separate from rock material which varies but little in its character in any one mine, it requires much less care than is necessary in most mining centres of the world. At the beginning of operations in that district most of the work was in the control of Cornish miners, who introduced the simplest of Cornish mills, namely, wooden stem pestles, with wooden shafts and cams. These were well suited to the small mines, and particularly to the limited means of transporting more expensive machinery. As these facilities improved, they were enabled to change to iron, and to vary their patterns of rods, shafts, cams, and mortars. The most approved pattern, finally obtained, is the square or round stem, with collar adjustable by means of keys. In its present form it is a bar of cold rolled shafting, an eye in the top, an adjustable collar with key-plate and keys, the head and a shoe of chilled iron. The stem is fitted into the head by a slight taper. The battery has heretofore been of wood, lined with chilled cast plates, and bed-plate of the same, but within the past year the California pattern has been introduced. The screens are of sheet-steel, drilled with 16 holes to the inch. During this period of trial and gradual improvement in the pestle stamps, in the years 1855-6, the Ball steam-stamps were introduced, and after years of labor and expense, have been made the most efficient and powerful machines ever yet used for the purpose. It is ostensibly the Nasmyth steam-hammer, and yet the

By H. F. Beeghly

UNTIL recently the only criteria by which steels were judged were their cost and their mechanical, chemical, and physical properties. The user was concerned with such properties as corrosion resistance, tensile strength, response to thermal treatment, hardness, ductility, and, to a growing extent in recent years, with behavior at high temperature. As plans were made to build power reactors, a new set of properties became important—the nuclear characteristics, which had to be considered by the designer and engineer in building his plant. The nuclear engineer developed methods for the rare and new metals and produced them in high purity, often at great expense. The pure metals then provided the raw materials for tailor-made alloys. For more common structural metals, such as steel, the nuclear industry depended on commercially available materials. Generally, the quantities required were small and specifications were rigid. It is not surprising, therefore, that difficulty was frequently encountered in procuring structural mate-

Jan 1, 1957

By R. A. Wagstaff

Many changes in equipment have had to be made to handle the flotation products at the blast furnace, and these changes have meant an expenditure of considerable money, which has not been compensated by an increase in smelting tonnage. To date, very few new lead mines have been developed, so that the help derived by the innovation of flotation has been directed to old producing properties, where the ratio of concentration is greater now than when gravity concentration was in effect. In some smelting plants there has been an abandonment of complete units due to the introduction of flotation. Flotation Products Difficult to Handle The physical characteristics of the flotation product do not make for economic handling for lead blast-furnace work, either mechanically or metallurgically. The millman or miner do not know what trials and tribulations they have passed on to the smelterman. To the smelterman it is "the everchanging flotation," for little does he know what new reagent will be perfected tomorrow that may completely change the grade and physical characteristics of the product. Even the mining companies who have complete units of mining, milling and smelting have had a hard time to reconcile themselves to the fact that the unit cost per ton of ore smelted must go up with the increase of flotation product on the blast-furnace charge. The "smelterman's burden," for that is what flotation has been for the last few years, has not caused the smelter operator to lag or fall down, but has spurred him on with new zeal. The physical properties of the flotation products are as follows: (1) High moisture content; (2) mucky nature of product; (3) fineness of product, and (4) high metal content. New Mechanical Devices for Handling Furnace Product These characteristics have caused the use of many new mechanical devices in smelting practice, for example: New transportation equipment, such as solid-bottom cars, is required; unloading equipment and sampling

Jan 1, 1928

By R. A. Wagstaff

MANY changes in equipment have had to be made to handle the flotation products at the blast furnace, and these changes have meant an expenditure of considerable money, which has not been compensated by an increase in smelting tonnage. To date, very few new lead mines have been developed, so that the help derived by the innovation of flotation has been directed to old producing properties, where the ratio of concentration is greater now than when gravity concentration was in effect. In some smelting plants there has been an abandonment of complete units due to the introduction of flotation. FLOTATION PRODUCTS DIFFICULT TO HANDLE The physical characteristics of the flotation product do not make for economic handling for lead blast-furnace work, either mechanically or metallurgically. The millman or miner do not know what trials and tribulations they have passed on to the smelterman. To the smelterman it is "the everchanging flotation," for little does he know what new reagent will be perfected tomorrow that may completely change the grade and physical characteristics of the product. Even the mining companies who have complete units of mining, milling and smelting have had a hard time to reconcile themselves to the fact that the unit cost per ton of ore smelted must go up with the increase of flotation product on the blast-furnace charge. The "smelterman's burden," for that is what flotation has been for the last few years, has not caused the smelter operator to lag or fall down, but has spurred him on with new zeal. The physical properties of the flotation products are as follows: (1) High moisture content; (2) mucky nature of product; (3) fineness of product, and (4) high metal content. NEW MECHANICAL DEVICES FOR HANDLING FURNACE PRODUCT These characteristics have caused the use of many new mechanical devices in smelting practice, for example: New transportation equipment, such as solid-bottom cars, is required; unloading equipment and sampling

Jan 1, 1928

By A. D. Hodges

The great mining region of Peru is a mountainous belt of country, running nearly the whole length of the republic, and comprising the two grand ranges of the Andes with the elevated table-lands between them. On the east of this belt are the extensive plains and fertile valleys of the Amazon and its tributaries. On the west is a narrow strip of coast 20 to 50 miles wide, for the most part a sandy desert, but producing abundant crops where irrigated ; and here are found petroleum (Department of Piura), salt (at Huacho and elsewhere), nitrate of soda in enormous amounts at the south, silver in a few localities (Province of Tarapaca), copper and other mineral products. The Western Cordillera, running nearly parallel with the shoreline, rises like a wall on the eastern side of the coast-belt, with passes from 15,000 to 18,000 feet high and peaks attaining 18,000 to 20,000 feet. Further east, at a varying distance, is the Eastern Cordillera, composed of broken mountain ranges which, considered as one group, have a general parallelism with the western chain, but individually vary greatly in direction, sometimes running nearly east and west, in places projecting out into the Amazonian lands, or here and there curving around to unite with the western ridge, and with this enclosing immense inter-alpine plains. These general features are indicated in Fig. 1. The surface of these plains is uneven and traversed by lower ranges of hills which surround large lakes, or rolling pampas, or fertile valleys; and through many of these last run rivers of considerable size. The whole country has a high altitude (averaging up to 15,000 or 16,000 feet), and slopes gradually north and east towards the Amazon, into which drain all its waters. Its bounding mountain chains are scored on all sides by narrow, picturesque and pre-

Jan 1, 1888

By H. W. Hitzrot, R. A. Limons, L. V. Fegan

The authors have developed and tested a new method for measuring pellet-bed temperatures in the traveling-grate or the shaft furnace. This method-using silver-palladium alloy wires as indicators-is less costly and less time-consuming than existing methods. Silver palladium wires, having specific melting points in the 2000° to 2500°F range, are enclosed in ceramic capsules. Each capsule is placed in a nichrome wire basket filled with a sample of green pellets, the baskets being the means for recovering the capsule after firing. After the encapsulated wires have been exposed to the firing cycle, the alloy wires are examined to determine the maximum temperatures attained by the pellet sample. This gives accurate, rapid determinations of maximum temperatures attained during pellet induration in either the traveling-grate or shaft furnace.

Jan 6, 1965

By Phillip A. Stoll, Young Ku Yoon

ThE deterioration of the magnetic properties of silicon-steel core materials during service (magnetic aging) is quite undesirable. Although some information about the effects of impurity elements on magnetic properties is available, 1,2 magnetic aging that occurs at low temperatures has not been extensively studied. Moreover, the microscopic techniques used by earlier workers were not suitable for study of fine metastable phases that are precipitated at relatively low temperatures. Recently, several investigators3,4 successfully used transmission electron microscopy in the study of low-temperature precipitation in Fe-C, Fe-N, and Fe-Mn-C alloys. To investigate metallurgical factors that affect magnetic properties after aging, the microstruc-tures of steels having different magnetic-aging

Jan 1, 1964

By Lawrence Burkhart, S. B. Joo

Axially unsymmetric ordered circulation patterns on the surface of a hemispherical constant volume drop with forced Internal motion were considered as a manifestation of hydrodynamic instability, which was affected by internal flow as well as by the properties of the interface A simplified mathematical model was analyzed In order to study the mechanism of onset of interfacial circulation from a non-circulatory basic state. Values of the critical Reynolds numbers were obtained when the basic state became a fully developed rotational flow and the values changed for different interfacial properties. The work describes a heretofore unreported surface flow pattern on drop surfaces From a practical point of new, any motion in the interface of a droplet can have a significant effect of mass transfer rates in solvent extraction processes Although surface motion in droplets actual processing equipment is very complex, continued study of the fundamental nature of such phenomena should ultimately lead to more effective equipment design procedures.

Jan 1, 1981

By R. G. Coyle

This paper describes a model of operating policies in an underground metal mine. The purpose of the model is partly that the problem of controlling a mining operation in the face of shocks from its economic environment is interesting in its own right, and also as an input to a larger research project on policy-making in mining companies. The model includes, mining, development and milling sectors together with cash flow and finances. In particular, it shows how the policies used to control the various sectors in the face of environmental shocks from metal prices and changing state of the system are connected by feedback loops. The use of feedback theory differentiates the model from 'ordinary' simulation and assists in the design of 'robust' policies which always achieve effective control. This model is the first stage of a major project and approximations have been made, simply to get the model going. The purpose of this paper is to show the kind of output this type of model produces, to lay our explicitly what is in the model and above all, to invite contributions from mining people on what the model should show and what should be put into it. We claim no virtues for this model. It is just a research tool so that later models will be more worthwhile and useable in practice.

Jan 1, 1977

By E. Gregory, C. G. Goetzel

The outstanding elevated temperature properties of materials made from sintered aluminum powder have been well established in recent years.1,2 and considerable investigation has been carried out on the structures which appear to be responsible for this type of strengthening.2,3 The maximum operating temperature of such materials is severely limited, however, by the low melting point of the aluminum matrix; and, therefore, considerable interest was aroused in methods of introducing the

Jan 1, 1959

By Shosei Serata

Conventional roof bolting may be giving ground to a new technique that utilizes only the ground itself to stabilize mine openings. This newly developed stress control technique (SCT) has initially been used in sedimentary ore bodies that are both overlain and underlain by weak strata. The technique is also suited to the design of production panels and main entry systems, and is readily adaptable to room and pillar as well as total- extraction mining, including both shortwall and longwall coal mining. In applications where the technique has been used, the requirements for roof bolting and floor renewal were virtually eliminated. The SCT comprises three basic methods and covers a wide range of problems associated with failing roofs and heaving floors in underground mines (see Table 1).

Jan 5, 1976

By R. V. Ramani, R. D. Zigmond, R. L. Frantz

In this paper, a computer program for determining the capital and operating costs for coal preparation plants is described along with its applications. The logic of the computer program is based upon the results of a survey of existing preparation plants, operators, plant contractors, equipment manufacturers, and consulting firms. This survey provided information on plant performance, order-of-magnitude costs, and costing procedures. Additionally, an extensive cost data file for the major capital equipment in coal preparation plants has been developed. Using the washability data and the computer program out- puts, the cleaning costs per million Btu can be calculated. Details about the program and its applications can be found in a report by the authors (Zigmond et al., 1979).

Jan 1, 1983

In 1803 the purchase of the immense territory called the province of Louisiana wm arranged between Thomas Jefferson, President of the United States, and Napoleon Bonaparte, First Consul of France. This central portion of what is now the United States was claimed in 1682 by the explorer Robert de La Salle for France, who continued to hold her title to the vast domain until 1762, when it passed by treaty to Spain, only to be retroceded to France in 1802, in consequence of Napoleon's military domination of Spain. Jefferson did not care to see New Orleans and its extensive hinterland pass into the hands of France. Spain did not matter so much; she was quiet and feeble, whereas France was restless and aggressive under Napoleon, who had dreams of founding a French colonial empire on the American continent. The expression of American feeling that Jefferson elicited came as a surprise to Napoleon, who concluded that a contest was not worth while, for his navy had been shattered by the English, and it was evident that only maritime supremacy could enable him to retain this trans-Atlantic possession; so he resolved to put it out of the grasp of England and at the same time replenish his military chest by selling Louisiana to the United States. The price was 60 million francs. By the terms of the Louisiana purchase a magnificent territory was added to the national domain; it covered more than a million square miles, or more than the total area of the United States at that time. Louisiana included the present States of Louisiana, Arkansas, Missouri, Kansas, Iowa, Nebraska, South Dakota, North Dakota, Wyoming, Montana, Oklahoma, with parts of Colorado, Idaho, and Minnesota; but

Jan 1, 1932

By A. L. Holley

The intention of this paper is not to discuss this important subject in all its bearings, but merely to point out why mechanical tests of steel, as ordinarily made, are not, alone, of any special value to engineers—certainly not to general mechanical engineers. The agents of the Barrow Hematite Steel Company, one of the largest and most successful Bessemer establishments in England, have recently distributed a report, made by Sir William Fairbairn,

By William P. Blake

At the August meeting of the Geological Society of America, I presented a paper on the occurrence of alunogen and bauxite upon the Upper Gila river, about 40 miles north from Silver City, New Mexico, together with observations upon the geology of that region." Inasmuch as the subject is specially interesting to metallurgists and mining engineers, and as our Transactions contain recent important papers, by Dr. Hayes, M. Laur, of France and others, upon bauxite, I venture to offer to the Institute, in more condensed form, an account of the deposits described in the paper above referred to. The only other published account of the alunogen locality which I have been able to find is a prospectus-pamphlet, issued in a small

Jan 1, 1895

By R. W. Raymond

THE important question of the metallurgical value of the coals of the Rocky Mountains and the Pacific Coast is to be settled, of course, by practical experiment. Meanwhile; as I have had occasion to point out, the proximate analyses of these coals throws little light upon it, and is, indeed, likely to mislead the metallurgist, if he compares it with the results of similar analyses upon bituminous and semi-bituminous coals. With the view of showing how large a proportion of the material usually classed as." volatile matters " consists of combined water, or oxygen and hydrogen presumably in chemical combination, I have collected a number of ultimate analyses from various sources, in the following tables. The numbered analyses in the first table are as follows

Jan 1, 1874

By William H. Love

ATLAS shaft was sunk to explore at depth a portion of the eastern end of the dry belt, or silver belt, of the Coeur d’Alene mining district. The Atlas mine is a mile east of Mullan and is on the south side of the Osburn fault. Equal partners in the venture are Hecla Mining Co., Newmont Mining Co., New Jersey Zinc Co. and Atlas Mining Co., the financing being equally shared by Hecla, Newmont, and New Jersey Zinc. As outlined the project had as its goal deep exploration of prominent structures developed in the Atlas in upper levels. Plans called for deepening the shaft from the 800 level to the 2400 level with subsequent drifting, crosscutting, and diamond drilling on the 2400.

Jan 11, 1954

By George Smith

IN discussing present-day business and industrial troubles we easily drop into the habit of clinical diagnosis. Talk of this kind, with its emphasis on suspicious symptoms and abnormal tendencies, makes us all morbid. As an English essayist has put it, we may thus induce a melancholy, temper that simply in-vites the ministrations of social and political quacks. It is far better-because nearer the truth-for us to recognize that our condition is in no sense diseased, that our body politic, social and economic, is suffering merely from growing pains; that America is not de-cadent-indeed, that any lapses from staid normality are traceable to the, excesses of youth. Our chief .trouble, then, is only that our industrial state is still young; it may be that we have been growing too fast. The growth in the industrial development of our country from pioneer days to the present time has been marvelous. Too many of us, however, take all this as a matter of course-we credit this record of American progress to our American genius alone. Too often we overlook the fundamental relationship between resources and progress-that man is aided and even guided by Nature. The fact is, social advance, indus-trial progress, national prosperity all have their ma-terial basis in natural resources. In furnishing the needed mineral raw materials to the great manufac-turing industries of the United States there has been no halt, but rather a general acceleration. No other phase of American activity can show-equal advance. As the decades have passed, the winning of mineral wealth has progressed from the role of a stimulus for western exploration to that of the foundation for nation-wide business. In 1890 the Sherman law was passed; since then the population of the United States has about doubled. Since then, too, thevalue of the annual product of the mines of this country has increased better than eight-fold-from 650 millions to 51/ billions of dollars. Since then the four largest branches of the mineral industry, which supply the iron and copper, the bituminous coal and petroleum-the bone and sinew and the energy of all other American industries-have increased their annual output nearly ten-fold as to value and six-fold as to quantity. Such a growth in the volume of mineral output must be taken as a true measure of the ex-ceptional service rendered by the mines of the United States. Not only is this a much larger country than it was 38 years ago, but its growing mineral industry has met demands that have been out of all proportion to the growth of the population.

Jan 8, 1928