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By John A. Mathews

During the prosecution of the aircraft-production program in 1917 and 1918, the writer visited many plants engaged in the manufacture of motors, planes and parts, in carrying out his duties as chairman of the Committee on Aircraft-engine Forgings. On several occasions, when the question of expansion was discussed, it was noted that there was confusion in the use of the terms: the true coefficient of expansion, a physical constant, and distortion in hardening. One engineer, referring to a steel shown in the accompanying table, stated that he could not consider it for crankshafts because of its excessive coefficient of expansion, while another steel, also Iisted in the table, was said to be especially good because it had no coefficient of expansion, since it came out of the oil bath perfectly straight. Many years ago one of our employees designed a new oil furnace; when asked what became of the products of combustion, he replied: "There ain't any, we burn them all up." While the coefficient of expansion is not without its effect in volume changes in hardened steel, it is not a determining factor in the matter of distortion and going out of shape. Irregular heating, uneven furnace bottoms, and carelessness in withdrawing the part from the furnace, as well as the manner in which the part enters the quenching bath are of greater moment. Generally speaking, also, steels of relatively low hardening temperature will distort less than those requiring higher hardening heats. The coefficient of expansion must be considered in engineering design most frequently when different metals or alloys are used in the same construction. For example, the difference of expansion between a steel crankshaft and an aluminum crank case might be of real importance and a steel with no coefficient of expansion would be much less desirable than one with the normal coefficient. About 15 years ago, the writer made many determinations of the coefficient of expansion at low temperature ranges, usually between 20' and 100" C. Among the materials tested were: Pure forged electrolytic iron, 11.73 parts per million for l° C.; cast aluminum (99.93 per cent. AI.),

Jan 1, 1922

By A. C. Watts

The question of disposition of the slack and dust so troublesome to coal mine operators of the West has been divided by your committee chairman into three heads, viz: The preparation and transportation of fine and powdered coal. The developments along the line of low heat carbonization. The uses to which fine and pulverized coal have been put. The development of low heat carbonization has been assigned to me. This is really not a part of the subject but as it has a most important bearing on the future use of coal, I presume the chairman thought best to include it. An English committee on smoke abatement makes the statement that the burning of raw coal is "dirty, wasteful and unscientific". I will go a step further and characterize it as an "economic crime." It has been predicted by eminent scientific men that eventually no raw coal will be burned for heat or power purposes. All this will take time, experimentation and large expenditure, but it will surely come. The question of disposition of slack and dust so troublesome to coal and utilization of its by-products has been retarded by the abundance and cheapness of the raw coal, and by the abundance of suitable coking coals for metallurgical purposes. But necessity is surely, if slowly, demanding that the enormous waste ensuing from the burning of raw coal for heat and power must cease. For instance, smoke abatement investigations in Manchester, England, showed that the increased cost of household washing was about $1,250,000 per year due to smoke and soot. It is estimated that in London 200 tons of soot and smoke particles are suspended in the atmosphere over that city during dense fogs and that much more than this is emitted from the chimneys each winter day during the forenoon. As an example of what benefits a smokeless fuel gives, it is cited that in the mill town of Shaw, England, the burning of smokeless fuels in the factories has reduced the so-called fogs by about 80%. Necessity, caused by the war led Germany into the field of low tem¬perature carbonization because of the shortage of motor fuel and lubricating

Jan 1, 1922

By Michael J. Messel

W. P. MOULD*—Has consideration been given to the problem of retreating the 4,000,000 ton tailings pile to recover the very considerable amount of asbestos fiber that was lost over the years due to insufficient operation and poor recoveries? Also, what was known about the possible content of chromite and the sulphides of nickel and cobalt? M. J. MESSEL (author's reply)—Consideration was given to the problem but nothing concrete has been done up to this time. W. P. MOULD—I am certain the tail- ings contain a very considerable quantity of fiber, not all of which is in the shortest lengths, because in the milling of talc rock from a neighboring location having a common origin with the asbestos bearing serpentine source of the tailings pile, a concentrate carrying 15 pct Ni and Co in complex sulphides and constituting about 4/10 of 1 pct of the talc rock was recovered. In the belief that the tailings also contained an appreciable content of chromite (then in demand, 1937) it was suggested to the management of the asbestos company that a truck load of the current tailings be sent to the flotation plant of the talc company where it would be put over the concentrating tables in an effort to discover the presence and roughly the percentages of chromite, nickel, and cobalt. Preparations for the test were woefully inadequate and the test was completely snarled up by the surprisingly large quantity of asbestos fiber from 1 in. long down to very short fiber, all of which matted up and plugged launders and pumps with disastrous effects and practically the total loss of the sample. If anything was indicaded by the test, it was that a wet process for milling asbestos was worthy of very serious consideration. M. J. MESSEL—A wet milling process for tailings retreatment only, is at present under study at our plant. One asbestos mining company in Canada has constructed a fairly large test plant for this purpose, but as yet no definite results have been obtained other than in a small test unit plant which were in some respects quite encouraging.

Jan 1, 1950

By R. C. Canby

The difficulty of exact neutralization by ammonia of the acid solution obtained in the determination of arsenic by the method of fusion with carbonate of soda and nitrate of potassium, led me to try the effect of neutralization by oxide of zinc. I obtained most satisfactory results, and found a great saving of time. The oxide of zinc being added in excess, there is no delicate testing with lit? mils paper and tedious alternate adding of dilute ammonia arid acid until the proper point is reached. The excess of oxide of zinc, too, seems to hold, from the filter, the gelatinous silica and alumina, which are usually precipitated upon neutralization, and thus to render the washing of the precipitated arseniate of silver almost invariably much more rapid. Except the substitution of the neutralization by oxide of zinc for the more tedious method by ammonia, the details of the process are practically the same as those published by Mr. Richard Pearce, of Argo, Colorado (Proceedings of the Colorado Scientific Society, vol. i.), who shows what very accurate results can be obtained by the fusion process. I have made numerous tests of comparison between the two methods of neutralization, and find that those by the oxide of zinc agree almost exactly with the old method. Increasing the quantity of nitric acid, even to considerable excess, to be neutralized by the oxide of zinc did not affect the precipitation of arseniate of silver. The process may be outlined as follows : Take 4 to 1 gramme finely pulverized ore, and mix in a porcelain crucible with eight to ten times its weight of a mixture of equal parts of carbonate of soda and nitrate of potassium (Kerl. Metallurgische Probirkunst gives 4 to 5 nitre to 14 soda). Gradually bring to fusion and keep so, three to five minutes. Cool. Disintegrate in hot water. Filter and wash with hot water. Acidify the filtrate with nitric acid, and boil to expel carbonic acid and nitrous fumes. Cool. Add an excess of an emulsion of oxide of zinc. The bottom of the beaker should have quite a layer of oxide of zinc, after stirring.

Jan 1, 1889

By J. Blodget Britton

IN the Journal of the Franklin Institute for May, 1870, there is published a description of a Colorimeter, together with a modification of the method proposed by Professor Eggertz, for determining combined carbon in iron and steel. An instrument of the kind there described, but of a little higher range, though in other respects not differing materially from the one originally made and used in the Iron-Masters7 Laboratory, I now submit to your inspection ; and I propose, also, to make some determinations minations with it for the purpose of showing how quickly they may be made, and enabling you to form some judgment of what reliance can be placed in the results. Professor Eggertz proposed only a single standard, and the solution to be tested should be diluted to exactly correspond in color with that of the standard, and the per cent. of carbon calculated after carefully noting and making allowance for the measures of water used in diluting. In practice, difficulty was found in bringing the color of the normal solution down to the exact shade of the standard; also other difficulties were met with in conducting the process, causing delay and interfering with the accuracy of the results. To materially overcome these, and after numerous attempts, an instrument such as is now before you suggested itself to me; and also I concluded to use a larger quantity of metal than directed by Eggertz, and, in addition, to filter the solution from its insoluble matter before making the comparison; and, more recently, to use an acid of just such strength as would completely dissolve the metal without the application of heat. Experimenting with these changes from the original method I obtained reasonably good results. The instrument, you will observe, consists of a series of tubes, sixteen in number, two and a half inches long, and about half an inch in diameter, standing upright, and securely fastened in a light, portable, walnut-wood frame, but separated one from the other so as to allow just sufficient space between to place for comparison the . tube containing the solution to be tested. The tubes are filled with

A. M. CANDY,* Pittsburgh, Pa.-I think more stress should be laid upon the question of welding with the carbon electrode, which we ordinarily call graphite arc welding. Mr. Miller's photograph indicated that the original parent metal had been decarburized to a marked degree. It would be interesting to know the carbon content of the parent metal, and whether or not Mr. Miller has made any investigations to determine if the metal is always decarburized or whether in some instances we actually have carbon injected into the weld, which has been the understanding that has been quite prevalent. There were one or two other points that Mr. Miller brought out concerning which I desire to ask one or two questions: The illustrations that he presented were obtained with what, I suppose, would be termed a real low-carbon steel welding wire, which gives in the deposited metal grains that are more or less symmetrical, whereas the Roebling electrode, which is a mild steel of higher carbon content, apparently gives a columnar structure. I do not know which-of these I structures is more desirable, but assuming that the structure produced by the really low-carbon steel wire is the more desirable, would it not be true that the very low carbon content would, probably owing to high temperatures that prevail in the arc, result in a greater amount of oxidation and probably result in either carrying into the weld more oxide or producing more oxide on the surface as the operator progresses? The short arc is an advantage in all cases. Whether Mr. Miller's trouble is oxide or nitride, the short arc helps him out, because the closer the end of the electrode is to the work the less chance there is for either oxygen or nitrogen to get in. And whichever is the cause of the trouble, the short arc keeps it out by lessening the time in which the steel is molten and the amount of air that gets in. It also makes sure that the molten metal will not fall into the crater. Everything is in favor of the short arc.

Jan 4, 1919

By Mark W. DeLawyer

The base of the stone quarry still stands today, as imposing as any Mavan temple or Egyptian pyramid. For 80 years it has been a reminder to those who must sweat to earn a wage. There are no plaques to indicate its impressive history. Rather, it stands as a towering monument to the masons and stone cutters who built it-a testimony in stone to that most demanding and back-breaking of industries. Take your imagination back to the limestone quarries at Split Rock, near Syracuse, NY. The sound of an occasional steam drill and the mighty roar of a dynamite explosion herald progress. The ring and crash of a hundred sledge hammers are music in the calloused hands of the quarry men. It is a symphony of man against nature. Hundreds of sweat-soaked men break up the blue Onondaga limestone for the "sodi ash," the popular name for the quarry owner, the Solvay Process Co. Nearby, expert stone masons fit mammoth 454-kg (1,000-1b) blocks of cut stone into place, building the foundation for what may have been, back in 1902, the world's largest stone crusher. Consider for a moment, a modern stone quarry. The business is now essentially one of machine against nature. The shovels, drills, conveyors, and locomotives help make the quarry of today a profitable venture. Now consider the quarry of the early 20th Century. Anyway you look at it, a tougher, more demanding life would be difficult to imagine-12 hours a day, all kinds of weather, breaking up tons of rock that had been drilled, blasted, or pounded from the bowels of an uncooperative earth. Before proceeding, it might be prudent to briefly describe the history of the Split Rock quarries. Before the purchase of the quarry lands by the fledgling Solvay Process Co. in 1889, the quarries already had a reputation literally chiseled in stone. Most of the municipal buildings in Syracuse were made of it, as well as over half of the Erie Canal, including the engineering marvel of the time, the Montezuma Aqueduct. This was where the Canal passed not only through, but in some

Jan 11, 1982

By D. T. Randall

In carrying out a general plan of ascertaining more efficient and more economical methods of utilizing the fuel resources of the United States, in order to prevent unnecessary waste and thus conserve the available supply, the United States Geological Survey made a series of experiments on the combustion of fuel in house- heating boilers. As it was realized that steam boilers of the ordinary types used for heating private houses are often installed and operated under conditions unfavorable to fuel economy and smoke prevention, these experiments were made with briquets, raw coal, and washed coal, so as to determine what is to be expected of these fuels in a representative house-heating plant, properly installed and operated. Briquetted coal had been frequently tested in the hand-fired furnaces under the Heine boilers in the Survey fuel-testing plant at St. Louis. The results were so satisfactory as regards economy and smokelessness that it was decided to conduct a series of tests to determine the value of this fuel for domestic heating purposes. Beginning in October, 1906, a number of evaporation tests were made on the house-heating boiler installed to heat the buildings occupied by the structural-materials laboratory, both briquets and coal being used. After these tests were well under way, it was thought advis- able to conduct some additional tests under conditions more constant than could be maintained at this plant. A carload of briquets was shipped to the University of Illinois engineering experiment station at Urbana, Ill., where two house-heating boilers of a size commonly used in residences were available. This equipment permitted more uniform conditions of pressure and capacity, making the results more valuable for comparison. Tests were made with this fuel at Urbana in June and July, 1907. The present paper is an account of both series of tests, and includes also details of tests made at Urbana on three standard fuels in the spring of 1908. Perhaps the most important result obtained is that showing the relative value of different fuels for domestic purposes. From Table 16. on page 39, it is possible by comparison to arrive at the probable value of any fuel in any part of the country. The figures in the table

Jan 1, 1911

Objective To develop safety training tools for mine health and safety trainers that fill gaps in currently available materials and help capture the wisdom and knowledge of “expert miners.” Background NIOSH began a series of stakeholder meetings in 1998 to determine what research was needed to improve miner health and safety. One of the more common concerns among stakeholders was a critical lack of appropriate training materials applicable to metal/nonmetal mining. Participants provided many insights into what effective training materials should include and how materials could best reach both new and experienced miners. The most important factors were that any materials be realistic and interesting and that some way must be found to capture the wisdom of expert miners before they retired. Approach NIOSH researchers chose videos as the best means of achieving these training goals. Over the past 3 years, NIOSH has produced three training videos that present information on safe work practices in underground mines: handling explosives, recognizing roof hazards and using proper scaling techniques, and installing ground supports. The last two videos, “Rock Falls—Preventing Rock Fall Injuries in Underground Mines” and “Miner Mike Saves the Day—or—Ground Support…It’s Important,” have won Alice Hamilton awards, NIOSH’s highest recognition of Excellence in Occupational Safety and Health, in the Educational Materials category. Two new videos are now being released. Both of these videos were shot completely in operating underground hard-rock mines and used expert miners to tell the story. Hazards In Motion The first, “Hazards in Motion,” deals with the dangers of working around mobile equipment in an underground mine. Ben, a new trainee, refuses to pay attention in his 40-hour New Miner Training class, and when the class takes its first trip underground, he wanders off and finds himself in many dangerous situations. He encounters many experienced miners who both chew him out for his unsafe attitude and give him advice and information on how to survive around mobile equipment. Many common pieces of equipment are shown, including haulage trucks, LHD=s, tracks and trains, slushers, skips and hoists, and air doors. The dangers of ignoring signals and of horseplay are also included. After nearly losing his life numerous times, Ben learns his lesson with the help of the Safety Angel, an experienced miner who looks suspiciously like his safety trainer. Ben’s Safety Angel saves his life repeatedly, teaches him how to work safely around these common conveyances, and introduces him to experts who have specific safety tips. Ben learns the error of his ways and vows to be the safest miner in the mine. “Hazards in Motion” is approximately 30 minutes long. Hidden Scars The second video is the first in the NIOSH “Expert Miner” series. “Hidden Scars” is a narrative interview with Don Capparelli, a miner and supervisor at the Sunshine Mine in north Idaho. This video captures the story of a fatal rock burst in May 1994, when Don was seriously injured and his long-time partner, Jimmy Findley, was killed. “Hidden Scars” is a very powerful story. Don Capparelli shares the physical and emotional pain he lives with daily as he relates the events leading up to the rock burst that took the life of his best friend and partner. This video is an excellent reminder of the human cost of uncontrolled accidents and the hidden scars that survivors must deal with for the rest of their lives. It runs approximately 25 minutes.

Jun 1, 2001

By W. P. Shinn

In a paper contributed by W. A. Goodyear, M.E., on "Water Gas as Fuel," read at the Boston Meeting, February, 1883,* the following statenlent was made: "The latest experiments on a scale of some magnitude in our citier, in the way of heating buildings and furnishing power for manufacturing purposes, have been by the distribution of high-presslire steam through pipes laid in the streets. Hilt these experiments (1) have not hitherto been very successful; and when we consider the high cost and (2) the great and unavoidable loss of heat and power, which always accompany the conveyance of high-pressnre steam to any considerable distance in pipes, to say nothing of (3) certain practical difficulties in the management of the pipes themselves, (4) it is evident that all such methods must eventually disappear before a system which can furnish a cheap gas of great heating power, easily distributed wherever wanted, without requiring pipes to stand pressures of 50 to 75 pounds per square inch, and (5) without keeping the whole mass of ground in the streets through which it passes hot, gratis, for a distance of ten or fifteen feet, in all directions around the pipes!' For the purpose of controverting Mr. Goodyear's statements in regard to steam-distribution in cities, I hare numbered the points made in his indictment, my principal object being, not a professional discussion of the technical and theoretical merits of steam vs. watergas, but a simple statement of facts, in regard to the present state of the street system of steam distribntion. Taking Mr. Goodyear's points in their order: 1. Concerning what he terms " These experiments," saying that they " have not hitherto been very successful," I propose to show, that the problem of stearn-distribution has passed beyond the experimental stage, and that its practical solution is highly successful. This will be shown by the facts hereinafter fully set forth. 2. "The great and unavoidable loss of heat and power whicn always accompany the conveyance of high-pressure steam to any con-

Jan 1, 1884

By Walter Bradley

MINING by hydraulic process of the important gold-bearing gravels of the Sacramento Valley in the basins of the Yuba, Bear and American rivers began in 1853, and continued at an ever-increasing rate for 30 years. In its most active days it reached an annual production of $15,000,000, and averaged $10,000,000 per year over the 30 years. During that period no provisions were made to prevent the debris from being dis-charged into the water courses, and ultimately large quantities of silt, sand and gravel were washed down to the lower valleys; filling channels, causing overflow of agricultural lands and difficulty in maintaining navigable depths in the Sacramento River. Agitation and suits filed because of these damages finally resulted in the injunction decision of Judge L. B. Sawyer,1 in the U.S. Circuit Court, Jan. 23, 1884, which closed down practically all hydraulic mining operations not having means to restrain their debris. In 1893 (approved March 1, 1893), Congress passed the act introduced by Representative Anthony Caminetti, of California, creating the California Debris Com-mission, composed of three officers assigned from the Engineer Corps of the U.S. Army, and since that time it has been legal and possible within the drainage systems of Sacramento and San Joaquin rivers to conduct hydraulic mining of gold-bearing gravels behind dams built under this commission's permit and supervision. In the watersheds of the Trinity and Klamath rivers, which flow directly to the Pacific Ocean and do not affect navigation or agriculture, operating permits from the California Debris Commission are not required. There is a measure of restriction there, however,. through what is known as the Trinity and Klamath River Fish and Game Dis-trict. Chap. 215, Stat. 1931, in order to secure relatively clear water for the fishing season, provides that between July 15 and October 15 each year there must not be discharged into these rivers debris that will cause a turbidity greater than a content of 50 parts per million in the

Jan 1, 1936

By M. Van Siclen

THE outstanding fact in connection with dust disease in the United States at present is the growing recognition of its seriousness by state officials and by the more progressive operators of mining, metallurgical and allied industrial plants. The same may perhaps be said of labor in some of its better organized centers, but the average independent non-union workman continues, as of yore, to suffer the toll of disability and even of death from dust inhalation without realization of the source of his ill-being. Progress in the betterment of the handling of sufferers from dust disease and of the conditions creating dust hazards in mining and allied industries is pursuing a course similar to that of the now widespread campaign against accidents, in which the risk is more obvious, more severe, and was naturally recognized sooner. The coming on of dust disease is generally relatively slow and its immediate effects not infre-quently masked by or attributed to other diseases. Marked exceptions to this general rule have occurred in districts where the dust is particularly pernicious, such as the Rand and Joplin; yet such exceptions, unhappy in themselves, opened the eyes of medical men, and of those in other localities charged with the responsibility for the welfare of industry, to the much more widespread if less spectacular hazard existing from the inhalation of dust in all rock-excavating operations and all industrial operations creating inorganic dust, whether it be crushing and grinding, sand-blast-ing, granite-cutting, or what not. Advancement to date in the United States in prevention and treat-ment has been slow, yet the record shows that quantitative methods for determining the degree of hazard and means for decreasing it were being developed as far back as 25 years ago; and that more rapid progress may be looked for from now on. In 1908, in this country, F. L Hoffman?(1) discussed the mortality from consumption in dusty trades, especially brass foundries; and in 1913 E. R. Hayhurst(2) described the effects of inhalation

Jan 1, 1933

By Roy W. Wright

Introduction The title of my paper is satisfyingly broad and allows me to touch lightly or dwell at length on virtually any aspect of mining, while endeavouring not to trespass on the subjects of other papers to be presented. However, at this stage in our world history when for the first time we are beginning to take conservation and the welfare of future generations more seriously, I want to concentrate mainly on the question of whether or not there will be the resources of minerals available to sustain mankind's progress in the generations ahead. Metals and the Population Problem The supply of raw materials is of course only one of the fundamental problems that will face future generations: if we assumed that the world population would continue to increase at the present explosive rate, then I believe we can say with certainty that other fundamental problems of much greater significance would arise long before a shortage of raw materials - or other substitutes -had any impact on the progress of mankind. Thus, I must start this paper with the assumption that some equilibrium in population will be arrived at before these other problems overwhelm the world. Will the Metals Run Out? At the 75th Anniversary Meeting of this Institute in March, 1947, Clinton H. Crane, President of St. Joseph Lead Co., prophesied that for the next 100 years there would be enough copper, lead and zinc for every essential need. He defined a need as essential where the qualities of the metal in that use were irreplaceable. Today, except for one or two cases such as lead in lead-acid batteries, few metals have qualities that cannot be provided either by another metal or by another material. It is more a question of what the engineer or manufacturer is prepared to pay for special qualities as compared with using cheaper materials and perhaps a less satisfactory design.

Jan 1, 1971

By Robert Ignouf

MY REMARKS, which I feel highly honored in being invited to make, shall be limited to a consideration of -the mining and metallurgical problems involved in this question; in fact, these problems alone might well be considered as suffi¬cient to explain the existence of the Ruhr situation and to justify the steps taken by France in this affair. Comparing the France of pre-war days with the France of the period following the Versailles treaty indicates clearly how the Ruhr question is a direct consequence of the new economic conditions which have prevailed in Europe since peace was signed between the Allies and Germany. Before the war, in 1913 for instance, the French out¬put of iron ore was 22,000,000 tons. This output, which decreased considerably during and immediately after the war, has about regained its previous level. It should be noted that 96 per cent. of the production of iron in France is obtained from the eastern part of the country, in the districts of Nancy, Briey,. Longwy, Metz, and Thionville. This concentration of practi¬cally all the iron mines into one district creates a very serious problem for France, involving strategic and economic consequences. The strategic problem arises from the fact that the whole iron resources of France lie close to the frontier of Germany, at a distance of only a few miles; hence it is of the' utmost importance for France to be assured that her eastern frontier shall not be at the mercy of a sudden invasion by an army which could in a few hours deprive France of her iron resources and render her powerless to defend herself. Invaded by her Eastern neighbor three times during the past 100 years, France has had dire experience with what such invasions mean for her. Wherever the German armies have passed, they have left an inefface¬able trail of desolation. France, therefore, intends to protect herself by sufficient and efficient guarantees against renewed invasions of her territory.

Jan 5, 1923

By Thomas Fraser, Abreu Alvaro

THE work described in this paper was carried out under the sponsorship of the Foreign Economics Administration and in cooperation with the Departamento Nacionál da Produção Mineral, Rio de Janeiro. The project was undertaken to obtain complete data on the variations in washability of coal to be used for coke manufacture in the steel industry and to determine the economy of preliminary hand-sorting operations. The coal-producing industry of Brazil is in that pioneering stage in which operat¬ing practices and methods are just being developed. Increased wartime demand for fuel, coincident with a drastic curtailment of foreign supplies due to lack of shipping facilities, has put a tremendous pressure on the national industry to furnish more coal. Under this incentive, production facilities are being expanded and new methods of operation are being tested. Such changes are being developed both by improvement of existing methods that originated in the field and by adaptation and modification of methods introduced from the United States and Europe. These mining condi¬tions and mining practices in Brazil are typical of what the American mining engineer will find in many instances when he goes pioneering into the developing coal fields of the Southern Hemisphere. The producing coal fields of Brazil are all in the southern states of that country. The coal measures are in a band roughly paralleling the coast and extending in a generally southwesterly direction from northern São Paulo through the states of Paraná, Santa Catarina and Rio Grande do Sul to near the Uruguayan border in the vicinity of Bajé. The accompanying map1 (Fig. I shows the general location of these fields and also the principal routes of movement of both national and imported coal in a late pre-war year (1940). Statistical data on production by states up -to that year are given in Table I. Rio Grande do Sul is still the largest producer among the coal states; but wartime

Jan 1, 1946

By R. W. Raymond

The western public domain acquired by the United States through trcaties, as the result of conquest or purchase, was invaded after Marshall's re-discovery of gold in California, by an overwhelming multitude of prospectors and miners from all parts of the world. he mineral lands of the whole Pacific slope were practically unsurveyed. Congress, disgusted with the experiment of leasing mineral lands, which it had tried for 40 years, and abandoned in 1847, enacted no laws for the management of these public mineral lands, and the pioneers made their own laws governing mining titles. These local regulations applied at first to gulch-mining in the auriferous river-beds only; and they constituted a simple and practical system. adapted to the needs and means of primitive communities—significantly called " camps." They had the means of measuring distances, but not angles; they knew no property except personal property in the form of pickaxes, pans, supplies, camp-equipage, horses or mules, and mining rights. The earliest codes which they developed expressed what might be called the law of the lariat. With the lariat they measured the distance assigned to each miner along the gold-bearing gulch—a double portion to the discoverer, and a single portion to his successors, in the order of their coming. With the lariat, they hung, after such due process of law as was available, the rascal who stole a horse, or a bag of gold-dust, or a mining claim, or killed another man without giving him fair notice and a chance to defend himself. In these pioneer codes, adopted in mass-meetings and enforced by the same authority, two features concern us most: 1. They measured mining property by one dimension only. So many feet of the gulch, held by one man, meant a distance into either bank, and a distance in depth, extending as far as gold might be found.

Jan 1, 1915

By Albert R. Ledoux

In Great Britain all analytical chemists are styled assayers, but in the United states a slight distinction is made, assayers being considered those analytical chemists who have chiefly to do with the determination of the precious metals. There have grown up around the assayers of precious metals a number of customs and traditions which, as a rule, do not fetter American chemists when called upon to determine the composition or constituents of any samples submitted to them for analysis. In Great Britain, on the other hand, trade-customs even go to the extent of enforcing the employment of an admittedly erroneous atomic weight in certain alkali-determinations. If the American chemist is asked to determine the amount of lime in a water, potash in an alkali, or silica in an ore, the owner of the sample does not presume to suggest what method he shall employ, nor does he question his report on the ground that he should employ another method. But even in America it is different with the assayer. Unfortunately for the guild, as well as for those who have to base business operations on the reports of assayers, customs and traditions as well as divergent interests seek to circumscribe him in his choice of method and sometimes dictate how he shall perform his operations. This was true at one time of copper, which to-day in England is still determined by the so-called Cornish fire-assay, an attempt to imitate in the laboratory the various metallurgical operations in the smelting-works; but nowhere in this country is the assayer forced to employ any particular method for determining copper so long as his certificate indicates the true total percentage of copper in the sample. It is true that both buyers and sellers demand use of the electrolytic method, but only because it is the most accurate. In America the trade accepts the assayer's statement as final, and makes

Jan 1, 1895

By J. H. Nead

The subject of this paper is one to which there are many references in the literature on the manufacture of steel in the open-hearth furnace, but few actual experimental data have been published. For that reason, the presentation of results obtained from two open-hearth heats where attempts were made to measure the sulfur absorption will be of considerable interest and value. The two heats on which the experiments were made were Armco ingot-iron heats and differ from the usual open-hearth heat of medium- or mild-carbon steel in that the refining is carried further; in this product the carbon and manganese are reduced practically to traces. In most other respects, and especially in respect to the absorption of sulfur from the producer gas, the two heats are typical of usual open-hearth practice. The object of the experiments made on the first Armco iron heat was to determine the fluctuation of the composition of the metal bath and the slag throughout the course of the heat, with especial reference to the variations in sulfur. It was hoped to determine whether there was an increase in sulfur in the bath from the producer gas and if so at what stage in the process the increase occurred. The experimental method consisted of charging analyzed scrap and pig iron, so that the sulfur in the charge could be calculated. Then, throughout the duration of the heat, metal and slag samples were takcn every half hour, beginning as soon as there was enough molten metal to take a sample. These samples were analyzed; the results are given in Table 1. All domestic scrap was used and the charge was made up as follows: Head End Finish Pounds Pound Pig iron........................ 36,300 Pig iron....................... 23,900 Sheet scrap bundles............. 36,200 Sheet bars..................... 23,900 Sheet bm..................... 40;200 The total charge, exclusive of the re-pig added near the end of the heat, was 160,500 Ib. The limestone charged was 21,400 Ib., or 13½ per cent.

Jan 1, 1924

By Olav Dalen

A HUNDRED years have passed since Wöhler made the first few particles of aluminum by decompos-ing aluminum chloride with potassium. In 1854 Deville used sodium to decompose the double chloride of aluminum and sodium, but even various subsequent improvements of the process, especially by Castner, did not sufficiently decrease the cost of the metal to bring it into general use. In 1862 Monckton proposed to reduce Al O? with carbon by the aid of the electric current, but the efforts of the Cowles brothers to do so were not successful and in 1884 they turned to making aluminum alloys by electrolysis. At about the same time Hall in America and Heroult in France success-fully worked out the technology of dissolving A12O3 in fused cryolite and electrolyzing the bath. It is hard to realize that forty years ago the annual production of aluminum was only 30 to 40 tons per year and the price of the metal thirty times what it is today. Great strides in decreasing the cost of production, improving the quality of the metal, and increasing the output have been made in the lifetime of middle-aged men. The large consumption of electrical energy in the form of direct current makes it necessary to locate aluminum-producing plants near waterfalls, to avoid transmission losses. Norway with its abundant water-falls is therefore a logical place for the development of aluminum production, even though it is necessary to import the bauxite, which is the raw material of the process. It was foreigners who first started the aluminum in-dustry of Norway and the first two plants were built by the British Aluminium Co. in 1906 to 1908; one at Vigeland near Kristiansand, and the other at Stavan-gerfjord in Nordfjord. These two plants are still oper-ating and producing over 3000 tons a year. When the plant at Vigeland is enlarged the production of the company will be more than 4000 tons a year.

Jan 11, 1927

By A. M. Starfield

The study of strain waves in rock over the past decade has, for the most part, been an investigation related, but not applied, to rock blasting; the design of rock blasts has proceeded on a basis that is independent of strain wave research. This duality is reflected in the paper by Dr. Clark.1 While the greater part of the paper is devoted to a discussion of spherical waves in elastic and visco-elastic media, it is in an entirely unrelated section, the section on scaling and cratering, that the practical approach to rock blasting is found. Work done by the U. S. Bureau of Mines, as described in the paper by Duvall, Atchison, and Fogelson,2 has established a correlation between crater dimensions and the peak compressive strain in the rock. Strain wave measurements have thus been used to compare explosives but have not, as yet, been applied to the planning of a production round once an explosive has been selected. The optimum burden, for instance, is still determined either by experience, empirical formulae (e.g. that of Langefors 3), or a cratering experiment and the theory that has been developed around that proposed by Livingston.4 Even then there is some ambiguity in applying deductions from short, concentrated explosive charges to the long charges often used in practice (although Bauer 5 reports doing this with considerable success) and wave theory has until recently thrown no light on this problem, being confined, with only a few exceptions, to spherical charges. The hesitation in applying strain wave theory has probably been due to two questions that have not been answered satisfactorily: just how important is the strain wave in rock breakage, and if it is important, under what conditions will the wave break rock? This paper is an attempt to answer the first question, to avoid the second question by an admittedly oversimplified assumption, and then to investigate the implications of this assumption for blasting with long cylindrical charges.

Jan 1, 1967