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By Franklin Bache

It is appropriate to the place of meeting, and of interest to those members of the Institute whose attention has been more or less directed to Virginia during the past eleven years, to know the result of recent developments of the Virginia coal-field. While, during the late " boom," the attention of the industrial pioneers of Virginia was mainly directed to iron-ore deposits and manufacture, it is safe to say that the coal to which, at that time, comparatively little attention was turned, and which did not directly foster a growth of " boom " towns, will prove the most reliable source of mineral wealth in the State. At the time of the last Virginia meeting of the Institute, held at Roanoke, in 1883, the Wise county coal-field was untouched by a railroad, and its economic existence was scarcely considered. Although, in the meantime, a number of reconnaissances had been made, and a fair estimate of the value of the field formed, it was not until 1891, when the Norfolk and Western and the Louisville and Nashville railroads, respectively, completed their Clinch Valley and Norton extensions to a junction at Norton, Wise county, that any development took place, and not until 1892 were shipments of any importance made. The coal-measures of Virginia are confined to the seven counties of Buchanan, Tazewell, Dickenson, Russell, Scott, Wise, and Lee,

Jan 1, 1895

FRANK N. SPELLER,? Pittsburgh,. Pa.-Mr. -Hayward's paper again draws attention to the fact that copper in steel is not the enemy that a good many of us it one time thought it was. He shows clearly that steel with over 0.75 per cent. of copper is as dependable, under the :conditions which he describes, as the same steel without copper. I might add that you-can weld copper-steel- satisfactorily up to that point; in fact, we have succeeded in welding pipe by the lap weld process up to 1 per cent. copper. Notwithstanding the date that have been presented on the effects of copper on the physical properties and corrosion of steel, a maximum copper limitation is still found in many specifications. In some cases the limit is extremely low, such as below 0.05 .or 0.03: per cent., or thereabout. That is a relic of days gone by, and I think the practice should be discouraged. E. F. CONE, New York; N. Y.-Not so many years ago steel-casting makers were very particular as to the amount of copper that existed in the pig iron that they used. They would not use copper-bearing pig iron unless mixed with non-copper iron. I do not know what the practice now is in the particular foundry where I was metallurgist at one time,

Jan 4, 1918

By T. Sterry Hunt

I HAVE already referred to this interesting locality in the opening address, but at the request of some of the members of the Institute, brought before them specimens of the ore and the accompanying rock. The ore, which is cassiterite, is also met with elsewhere in Maine, at Paris and Hebron, but it there occurs associated with orthoclase, quartz, tourmaline, and beryl, in concretionary granite veins, which cut the micaceous gneisses of the White Mountain series. At Winslow the veins traverse an impure gray micaceous limestone, which is found in many parts of this region, and is subordinate to the same gneissic series. The veins, which are seldom more than an inch or two in thickness, are abundant through a considerable breadth of the rock, and are interlaminated with it, occupying places between the sedimentary layers, which are distinctly marked by different shades of color. Occasionally, however, they cut across the stratification for a little distance, showing that the disrupting action was not always confined to tearing the layers apart. The vein-stone consists of purple fluor-spar, and silvery white mica with quartz. In this gangue the cassiterite, nearly black in color, is disseminated in small crystalline masses, sometimes one-half an inch in diameter, and is associated with a little mispickel. I have only seen the veins as exposed at a single point, but was informed that similar veins holding the ore are met with at a distance of several thousand feet

By Joseph Hodgson

Introduction SINCE about 70 per cent. of the total cost of mining is due to underground work which is out of sight, it is essential that expenditures should be made here to the best advantage. A great many mistakes have been made which were expensive, but perhaps these have not even been detected by mine owners. In the future these may be minimized to some extent, especially if there is cooperative effort on the part of each employee. I have been interested in this subject for some years and have tried to deduce principles and methods. These have proved highly advantageous and may also be of help to others. Some corporations, like the United States Steel, and the Cleveland-Cliffs Iron Co., have done a great deal in this field by having stated meetings of their organizations, with the view to interchanging ideas among their men and educating them along the lines of concerted effort. Since no man knows all about the various branches of mining, it is advisable that frequent meetings of the operating department be held for the interchange of ideas and that all members of the organization have an opportunity to express themselves on the various subjects. It has often been found that in discussions between heads of departments, foremen and bosses, many valuable suggestions may be obtained which promote the best interests of the company. The method regarded as the most conducive to cooperative effort, and pursued by the organization, is to analyze and develope the different phases of various mining subjects at regular meetings.

Jan 5, 1916

By W. Spencer Hutchinson

It is the purpose of this paper to describe a method used to determine the corundum contents of samples of hard crystalline gneiss containing both corundum and red garnet. A chemical analysis of the rock for alumina would not fix the amount of corundum became at least three other constituent minerals of the rock, mica, feldspar, and garnet, contain alumina combined with silica. Following are the principal minerals found in the samples, together with their specific gravity and hardness as given by Dana: The corundum occurred in crystals of a gray or bluish gray color, in minute grains and coarser up to 0.5 in., and no massive or block corundum was observed. The larger crystals were commonly quite slender, well defined, and the normal hexagonal form clearly developed. They lay with the structural planes of the gneiss, and sometimes appeared prominently in relief on weathered surfaces. In some cases these crystals had suffered partial or total alteration to mica, margarite, or other soft minerals, a condition illustrated by sample D, which appeared to be studded abundantly with corundum on the flat faces. Garnet, a striking feature of nearly all the samples, was present in small rounded crystals of a pink to red color. The samples were first broken to pass a No. 4 mesh screen. This was done with a hammer on an iron plate, particular care being taken to avoid the breaking of the crystals finer than need be to pass the screen. A portion of the sample weighing 500 g. was then taken and, with a little water added, was scoured round and round in an iron bucket with a wooden block, until the coarse crystals of corundum were cleaned of adhering pieces of mica. The bucket was then re-

Jan 1, 1914

The housing of labor and sanitation at mines in India are difficult problems to solve because-no more than two or three castes will accept the same conditions, and conditions suitable to one coal-field are not applicable to other fields. It is also necessary to consider the financial standing of the different companies. The European companies, which pay 30 per cent. and more dividends, can erect more suitable houses than the Indian companies, which are just able to keep their heads above water. The Santhal will not live in a bucca-roofed house as a permanent dwelling, and both the Santhal and Koras have an aversion to living in a line of attached huts. They have forsaken a whole, line of houses in one of which a case of sickness or death has occurred, and those houses were afterward considered unfit by all other classes of natives. The Santhals, Koras, and Douri castes will not take drinking water from a stand pipe; wells must be furnished. When well water is not available, these people will take water from the nearest pool or tank regardless of whether or not the water is stagnant. The well tops should not he completely enclosed, nor should there be a drain around the top. The ground should slope away from the well. In the Girieih coal fields, the miners have a great objection to pucca floors; they prefer earth which is lapped, easily cleaned, and renewed. As it is customary for the miner to build his own house, the company supplying the roofing material, he takes a special interest in it, keeps it in order, and hesitates to leave it. Each house is surrounded by its own bit of land, which the inmate cultivates.

Jan 12, 1918

By H. C. Kenny

THE annealing or softening temperature of cold-worked copper is appreciably increased by almost unbelievably small amounts of silver. As indicated by some data in this paper, the softening temperature of high-conductivity, tough-pitch copper may be increased from 200° to 350° C. by the addition of only 15 oz. per ton (0.052 per cent) of that element. Because it has this higher annealing temperature as compared with the silver-free metal, silver-bearing copper finds considerable use in industry. For example, when hard-rolled copper is used in operations that involve soldering or tinning, silver-bearing copper insures against loss of strength, whereas silver-free copper becomes "dead soft." Yet-though several investigators, beginning with Caesar and Gerner1 in 1916, have shown that small amounts of silver do definitely raise the softening temperature of copper-data are lacking on the problem: What is the specific influence of different amounts of silver on this tem-perature? It was to help in filling this gap in the knowledge of what might be termed "alloy coppers" that the data given herein were obtained. The softening of cold-worked copper depends, of course, on a number of factors, of which the composition of the material is only one. Other highly important factors are the degree to which the material is cold-worked and the time it-is held at the annealing temperature. The method of cold working and the grain size of the metal produced are also signifi-cant. All these variables were taken into account in the investigation reported here, and the influence of silver on the electrical conductivity and on the working was also considered.

Jan 1, 1934

By Clarence M. Haight

The general practice in drill sharpening shops, of which descriptions have been written, is about as follows: The bit is heated to 1600" to 1900°F. Then when forged to the proper shape and size in the sharpening machine, the steel is allowed to cool; it is then passed to a hardening furnace where only the end is heated to about 1450" F., and then quenched in cold water, brine, or in brine with oil on top.

Jan 1, 1922

By O. E. Kiessling

Viewed from the standpoint of an economist, the task which faces the petroleum producing industry is one of intelligent adjustment so that technology can perform the job of efficient exploitation, while at the same time the interests of producers and consumers remain adequately protected. The crux in the task of making this adjustment lies in the difficulty of arranging the instrumentalities of production to accord with the physical characteristics of oil. For example, oil is exploited under a competitive economic system based on private ownership and contract, with the hope that profits will attract capital and enterprise, and with competition supposedly acting as the regulative factor. Whether such a scheme of industrial organization works is partially dependent upon the ability of the producer to withold or produce his commodity as he sees fit, in accordance with market demand. But in the oil industry, the enterpriser does not have complete control over the expansion and contraction of production, for, because of the decisions of the courts that ownership in oil depends upon its possession, desire for immediate output becomes the controlling force in production. Consequently, the theoretical commands and restraints of free enterprise are not operative because there is no security of property, and the result is loss due to the following economic maladjustments: (1) Production not completely responsive to price control. (2) Production at excessive cost. (3) Loss of oil, a highly exhaustible natural resource. If economic maladjustments are to be eliminated, there should be a change in the organization of production so as to provide efficient exploitation of the oil and at the same time to insure individual property interests. The latter is necessary if economic considerations are to become primary factors in regulating production. To attain these ends, the entire pool should be developed as one big engineering project and some scheme

Jan 1, 1928

SINCE I promised you above when speaking of the melting of metals to teach you to make small crucibles and shells for melting, I do not wish to fail in my promise. For, in truth, since they are instruments that are much used for this procedure, they increase the work if they are not good, and often cause great extra expense as well as necessitating repetition of the work. If they are good they save everything. Therefore, if you have to make them, do it so that they, are greatly aided by art. It is first necessary to have the clay of a good nature, that is, resistant to the force of the fire by its own natural virtue, either when it is lean or when its viscousness is mixed with much talc, and whether it is yellow or white. This should be well freed from small stones and beaten well with an iron, and then thoroughly mixed by hand. With this should be mixed an eighth part of finely ground and sifted iron scale,* and also some [145] young ram's-horn ashes. These things should be well mixed together by hand and by beating them. If this clay should not be strong enough by itself, it is mixed with another lean clay, with crushed peperino, flintstone, or some other stone that in your judgment seems to be arid and resistant. Crucibles are worked on a low potter's wheel turned by hand, or on a high one turned by foot, just as plates are made. Both large and small ones are made. Most of them are given a triangular shape at the mouth, and the shells have a kind of spout for ease in pouring out the metal. This done they are well dried, and baked in furnaces like pots or other vessels. At the end, when they have been thus made they are used for melts.

Jan 1, 1942

By Milnor Roberts

The Nicola Valley coal-field is small, but it seems likely to become important because of its commanding position in a rich region that is developing rapidly. Bituminous coking-coal in workable quantity has not been found at any other point between the Crow's Nest Pass region, about 400 miles to the east, and Vancouver island, 250 miles westward. The Canadian Pacific railway reached the Nicola valley two years ago ; two other lines, the Canadian Northern and the Great Northern, are building towards the valley. The vast region between the Rocky mountains and the Pacific coast, extending northward for several hundred miles from the international boundary, which has been the scene of extensive mining- and smelting-operations for many years, is filling up with settlers, who are attracted by the wealth of minerals and timber, the rich soil of the valleys, and the fine climate. The Nicola river, flowing westward through the valley of that name in the Yale district, discharges into the Thompson river, which is the eastern branch of the Fraser. The transcontinental line of the Canadian Pacific railway crosses the mouth of the Nicola river at Spence's bridge, 178 miles from Vancouver. From Spence's bridge the Nicola branch line ascends the valley for 40 miles to Merritt, the coal-center, and continues 7 miles farther to the town of Nicola. Thus the haul from the mines at an elevatioiz of 2,000 ft. to salt water is 218 miles down river-grades. The Nicola branch will be continued about 150 miles farther eastward to Penticton, where it will connect with an extension of the line through the rich Kootenay and Boundary districts. The Canadian government has granted a subsidy of $6,000 per mile, to which the provincial government is planning to add $5,000 per mile, to assist in the construction of the Nicola extension. Upon the

Jan 1, 1910

BEING at the crossroads, metaphorically speaking, seldom has the advantages of the literal sense of the words. One seldom has precise knowledge of the existence of the metaphorical crossroads or forks in the road of life. A case in point is the Committee on Education of the Engineers' Council for Professional Development, which for twenty years has been accrediting the engineering curricula in the educational institutions of the United States. The committee is now at odds with itself and with the National Council of State Boards of Engineering Examiners over the accrediting of courses which in the opinion of many engineers are not strictly speaking engineering curricula at all. Such courses include: fire protection engineering, crystal engineering, nuclear engineering, and geological engineering. The crossroads might be placed arbitrarily somewhere between 1936 and 1938 when the committee first started accrediting curricula and included the first course in industrial engineering. Purists might argue that the committee first wandered from the straight and narrow when it recognized subdivision of engineering into the major branches of mining, metallurgical, civil, mechanical, electrical, and chemical engineering. Accrediting is certainly an important function because it provides a standard for engineering education and it should be done on a national basis by an unbiased group like the Education Committee of ECPD. Students, educational institutions, and industry derive great benefit from proper standards. The autonomous State Boards of Engineering Examiners have long accepted ECPD accreditation as evidence of the required academic training of engineers aspiring to licensing. But the State Boards today question the wisdom of applying the name engineer to graduates of some of the so-called fringe curricula. The Education Committee, having gone so far in accrediting some of them, has numerous applications pending for accreditation of similar curricula and even new courses never before accredited. Arguments against recognizing highly specialized engineering curricula are numerous. The Salary Stabilization Board has disallowed industrial engineering from classification as engineering for its purposes. A graduate of a specialized course in geological engineering at a school in the Southwest slanted heavily for practice in the petroleum industry might not be interchangeable with a graduate of a similarly designated curricula at one of the institutions in the North Central states where the emphasis might be on metallic. mineral deposits. Industry in general should not expect the universities to supply a degree in each of the specialized engineering classifications it might set up for purposes of salary or job designation. Having gone so far, it is easy to understand the difficulty of the Education Committee. ECPD might well call a moratorium for the purpose of taking stock of its position. If the present trend is allowed to continue, it is apparent that an engineering institution could be subdivided into a multiplicity of departments teaching specialized curricula resulting in a subordination of the basic concepts of engineering. Although the parallel of the medical profession is trite, it should be pointed out that degrees in medicine are not labelled by the numerous specialities practiced by doctors. For practical purposes the ECPD would do well to accept the fact that the crossroads have been overreached "and protect the engineering profession by coming up with minimum standards for an engineering curriculum.

Jan 1, 1952

By G. B. SOUTHWARD

MECHANIZATION is being developed to some extent in every coal field in the United States and it is rather difficult to say which State or section of the country has made the greatest advancement. Statistics now being compiled for 1928 will show the tonnage mined, the amount of equipment used in each of the coal-producing States, and the comparative tonnages and percentages of total tonnage mined in each of these States, and will reveal which field is making the greatest advancement as far as quantity of production is concerned. However, while the tonnage figures are of great importance there-are other phases of coal-mine mechanization, such as the types of equipment, the mining methods and coal bed conditions, which are of equal interest. The change from hand-mining practices in all of the various operations from the face to the railroad cars is, perhaps, more indicative than any other one thing of the real progress being made.

Jan 1, 1929

By F. H. Wilson, E. W. Palmer

Brass mills are familiar with a recurring problem which reveals itself during deformation of annealed metal as an opening up of cracks which are suggestive of a grain boundary pattern. A typical example is seen in Fig 1, which shows part of the convex surface of a cartridge brass disc which was slightly dished by the punching operation. Another illustration of the same type of defect was found in the surface of a finished cartridge case which split open on firing. These cracks, shown in Fig 2, were away from the split but indicate the presence of the type of weakness which permitted the splitting. Usually the weakness consists of separate cracks, the lengths of which are of the same order of magnitude as the grain size prior to the final anneal. Their typical appearance in a polished section is shown in Fig 3. This structure was found below the surface of a fractured tensile-specimen that had been cut from a large cartridge blank showing the defects on its convex surface. While the pattern formed by these cracks suggests a grain boundary origin, the cracks bear no relation to the currently existing grain structure. Thus Fig 3 shows that the grains have grown up to cracks already present. Since it is doubtful that the cracks were present in the metal before the anneal, they must have formed during the anneal but prior to recrystallization. The term "fire-cracking" has been generally applied to cracking that occurs during an anneal under the influence of internal stress, but refers more specifically to obvious macroscopic cracking attributable to the presence of a low melting phase, usually lead. Since the type of cracking described above may occur when the lead content is very low, we have considered it a somewhat different phenomenon, and have called it "inter-granular parting." While most examples involve cartridge brass, intergranular parting has also been observed in the fabrication of large seamless tubes from discs of both 85/15 red brass and 70/30 cupro-nickel. Similar cracking in nickel silver was investigated by Jones and Whitehead,1 who showed that it could occur during healing or cooling. That which occurred on heating they called "fire cracking," and they suggested that, a transformation at about 320°C might account for its occurrence. It was felt in this laboratory that the observed parting was probably one aspect of the general observation, first made by Rosenhain and Archbutt,2 that a tendency toward intergranular fracture under tensile stress increases with increasing temperature and decreasing rate of strain. In this case the stress involved would be internal. The rate of strain would be exceedingly slow, a localized internal creep. Reference to the literature uncovered no efforts to extend the observations of Rosenhain to conditions involving only internal stress. Accordingly, an exploratory research, sufficient in detail to satisfy us as to the probable truth of this explanation of the observed intergranular parting, was undertaken. The internal stresses present during the early stages of an anneal (prior to recrystallization) would be from two sources: residual stresses developed during deformation, and thermal stresses caused by uneven heating and expansion. Thermal stresses would vary widely according to shape, size and manner of heating, and can be considered as supplementary to residual stresses. It seemed necessary to determine the stress and temperature conditions under which parting would occur in a relatively short time, and then to establish whether or not in- ternal stresses may persist to an extent adequate to cause parting at such temperatures. (Jones and Whitehead1 and Moore and Beckinsale3 made tests which indicated that stress relief required an appreciable time.) During the course of the research the desirability of studying the effect of grain size became apparent, and this factor is one of the major variables of our investigation. Intergranular Parting under Tension at Elevated Temperatures In early experiments, hard 70/30 brass tensile specimens, with unknown residual stresses, held for 10 min. at applied stresses from 30,000 to 40,000 psi at temperatures from 300 to 350°C, showed no macroscopically visible cracks when unloaded and cooled, but cracks very similar in appearance to those observed in commercial practice were revealed in these specimens by pulling them to fracture. Annealed specimens, on the other hand, showed no cracks in such experiments, apparently because they deformed plastically at stresses below those necessary to cause parting in a reasonable time. Hence, the specimens used for this study were first strengthened by cold tensile elongation, giving them an unavoidable residual stress pattern (determined largely by grain size and orientation) which would, however, correspond in direction, at least, to the stress pattern obtained under stress at temperature. A variation in these residual stresses might be expected with variations in grain size, but following any given anneal the reproducibility of stress pattern should be as good as that of the grain size measurement. With no information as to the effect of the amount of prior deformation, tests were conducted on specimens given the same cold elongation, using a stress applied at temperature which was a constant proportion of the stress required to produce this elongation. In

Jan 1, 1950

By H. Landsberg

IN a previous report1 it was pointed out that a successful attack on roof troubles has to be preceded by extensive scouting. As Lord Kelvin once said, scientific progress can be made only if accurate data are available: "unless you measure, you do not know.? THE CONVERGENCE RECORDER For the observation of roof movements in mines the convergence recorder has shown that it will enable us to get some of the necessary information. Results with convergence recorders were first published by Winstanley and other English investigators for rapidly moving longwall faces. In their investigations the speed of work and the heavy over-burden produced a considerable amount of absolute values of convergence in a short time. Under the conditions frequently encountered in our investigations in Central Pennsylvania, under shallow, overburden and in mines with slowly proceeding extraction, the movements observed were much less in absolute value, for an equal interval of time. This was partly because the mines in which our studies were carried on frequently had idle days, sometimes four or five in succession. Therefore continuous records were not employed and a simple convergence gauge was built. In its first models, it consisted only of two telescoping tubes pressed against roof and floor by a coil spring. At the side of the lower tube a rule divided into 1/-mm. divisions was fixed and a knife-edge, which was attached to the upper tube, was slid over the scale in case of convergence between roof and floor. While the larger motions could be read on this device, it seemed to be desirable to increase the accuracy by inserting between the two tubes a dial meter reading in 1/1000 in. Such a gauge was first built in April 1937 and installed for experimental purposes in a bituminous coal mine in Pennsylvania (Fig. 1). It was read at least once daily, 24 hr. apart, and if feasible at shorter intervals. After several months of experience it can be said that this type of gauge answers the scientific as well as the practical needs. It is easier to handle than the recorder; no clock is used, there are no pen troubles. The price of

Jan 1, 1938

By Eugene McAuliffe

It is not possible to include in this paper, limited as it is in scope, the many diverse steps toward the reduction of mine accidents that are taken in the mines that produce the nation's coal. Every coal-producing state has enacted laws covering proper mining practices, and the major portion of these are directly related to the safety of the mine employees. The United States Bureau of Mines, the American Institute of Mining and Metallurgical Engineers, The American Mining Congress, a number of national, regional and state organizations, as well as the coal technical press, have covered time and time again all of the '(do" and "don't" phases of mine operation that bear on the important question of mine and employee safety. Within the past 15 years The Union Pacific Coal Co, has attempted to put into practice in its mines in southern Wyoming these many good recommendations, finding some value in all, and yet, to secure substantial results, the management found it necessary to resort in the end to what might be referred to as i'extra-territorial" methods. It is the writer's purpose to show in this paper that marked and even extraordinary betterment, can be brought about when employer and employee work together with due sincerity. In presenting our own experience, one that has been duplicated in so far as results are concerned on numerous other properties, no theory of perfection of management exists; on the other hand, our organization feels that as long as our record of accidents remains as shown by even our latest and best performance we still have far to go. Safety work in some form has been carried on in and about the mining properties of The Union Pacific Coal Co. since the first mine was opened at the now long-abandoned town of Carbon, Wyo., in 1868. On June 30, 1903, an explosion and subsequent mine fire occurred in mine No. 1 at Hanna, taking 169 lives, and a second explosion occurred in the same mine on March 28, 1908, in which 59 additional lives were lost. Looking back with impartiality on the causes leading up to these two unfortunate disasters, we can only conclude that shooting from the solid, the absence of adequate ventilation, rock dusting, the use of water at the face to allay

Jan 1, 1938

By Eugene McAuliffe

It is not possible to include in this paper, limited as it is in scope, the many diverse steps toward the reduction of mine accidents that are taken in the mines that produce the nation's coal. Every coal-producing state has enacted laws covering proper mining practices, and the major portion of these are directly related to the safety of the mine employees. The United States Bureau of Mines, the American Institute of Mining and Metallurgical Engineers, The American Mining Congress, a number of national, regional and state organizations, as well as the coal technical press, have covered time and time again all of the '(do" and "don't" phases of mine operation that bear on the important question of mine and employee safety. Within the past 15 years The Union Pacific Coal Co, has attempted to put into practice in its mines in southern Wyoming these many good recommendations, finding some value in all, and yet, to secure substantial results, the management found it necessary to resort in the end to what might be referred to as i'extra-territorial" methods. It is the writer's purpose to show in this paper that marked and even extraordinary betterment, can be brought about when employer and employee work together with due sincerity. In presenting our own experience, one that has been duplicated in so far as results are concerned on numerous other properties, no theory of perfection of management exists; on the other hand, our organization feels that as long as our record of accidents remains as shown by even our latest and best performance we still have far to go. Safety work in some form has been carried on in and about the mining properties of The Union Pacific Coal Co. since the first mine was opened at the now long-abandoned town of Carbon, Wyo., in 1868. On June 30, 1903, an explosion and subsequent mine fire occurred in mine No. 1 at Hanna, taking 169 lives, and a second explosion occurred in the same mine on March 28, 1908, in which 59 additional lives were lost. Looking back with impartiality on the causes leading up to these two unfortunate disasters, we can only conclude that shooting from the solid, the absence of adequate ventilation, rock dusting, the use of water at the face to allay

Jan 1, 1938

By F. Selig, E. J. Couch

The following points serve to supplement the interesting theoretical study on forward combustion by Thomas, and may be of some general interest. The mathematical model presented by the author can be viewed as a first approximation to the problem of calculating the vertical burned height profile resulting from ignition of the interval | z |<h/2 in a very thick formation. However, the assumption of a given minimum combustion temperature T, would give a better approximation to the vertical burned profile if the burning height were not constrained to stay within the ignited layer. This follows from the fact that both fuel and oxygen are present in the adjacent region, |z|>h/2, and for certain combinations of process variables the temperature is sufficiently high for complete combustion to occur. In this case, the vertical coverage will first become greater than the ignited interval before cutting back to zero as the extinction limit is approached as shown in Fig. 1. Such growth of vertical coverage is possible if the minimum combustion temperature is less than the initial source temperature (r = rj) at the edge (z = h/2) of the ignited interval. But this latter temperature is equal to one-half the source temperature for the case of infinite burned height.&apos;,&apos; Thus growth will occur initially if The fact that the vertical burned height can be greater than the ignited interval complicates the picture considerably, as can be seen by referring to Fig. 1. Here burning occurs in Region A, whereas none was possible in the original mathematical model. At the same time, there is no combustion in Region B, contrary to the assumption of burning in the entire layer |z|<h/2. This apparent inconsistency suggests that the vertical coverage derived from this simple model does not adequately represent the vertical height of the burned zone. A more compatible model will result from the actual stepwise calculation of the burning length (as a function of time) that would give rise to the specified combustion temperature. This problem can be more conveniently attacked by using the temperature distribution, given by the author&apos;s Eq. 12, expressed in the integrated form:

JESSE L. JONES,* Pittsburgh, Pa.-I would like to ask Miss Erskine if down-draft has been used in any of the foundries where heavy fumes have to be removed, instead of the overhead draft.? L. -ERSKINE.-The system of overhead draft to remove heavy fumes has been very much more successful. The entire efforts of the New Jersey Department of Labor in regard to stabilizing conditions in the foundry are the result of the physical examination of the foundryman himself on first-hand information as to the prevalence of the minor ailments and the bad timekeeping that naturally accompanies them. These ailments are a factor in not only increasing the labor turnover but in increasing the percentage of bad work as well. The physical exertion of the foundryman himself is of course an important factor. In certain standard shops the amount of energy expended runs from 11 to 13 tons of foot-pounds of energy a day. In certain shops on piece work, I found a record of the energy expended per day to run as high as 22 tons. In one shop, during the war period, the management established a bonus system, and the men increased their output from 60 to 100 molds a day. The result was an increase of some 60 per cent. in output, and an increase of 400 per cent. in defective castings. The question of the physical exertion in the unsanitary foundries, of course, is very much complicated by other factors, for which reason the department has devoted a good deal of attention to estimating what is a reasonable exertion in a sanitary, well ventilated foundry. We have met certain physical difficulties in the brass foundries that the iron foundries did not have. All that information is available through our Bureau of Industrial Information. The question of the physical energy exerted by the molder is found to have a very distinct bearing on the question of contracts, for the possibility of increasing production is balanced by the extra overhead involved. JESSE L. JONES.-I would like to ask if any evidence has been noticed of carbon-monoxid poisoning among the employees of the foundries.

Jan 4, 1919

By James E. Chapman

The observations here presented are not those of an expert accountant, but of one who, while he has seen considerable service in the accounting departments of large companies, has spent more time in engineering and operating. This paper is intended to cover, in a measure, mine accounting for small mines, as distinguished from the elaborate systems, requiring many persons in the accounting department. I shall attempt to outline a system embracing the essentials of accounting, and simple enough in form to permit one or two persons to carry it on from month to month, in sufficient detail to be able to tell quickly the grade of ore, the prices received for metals, costs per ton for mining and milling, costs per foot for development, upward or downward tendencies in costs, ore settled or in transit, cash on hand, stocks of supplies on hand, efficiency of labor, etc. As in all accounting, there are two main divisions: that of revenue received for what is sold, and that of disbursements made for what is bought, so in mine accounting we have to consider chiefly the income derived from sales of ore or concentrates, and the expenses incurred in producing the said ore or concentrates in a marketable condition. I. Income The revenue of a mining company from the sale of ore or concentrates comes in the form of remittances, accompanied by settlement sheets made out by the buyer of the mine product, such as a smelting company. It is the duty of the mine accountant (or the person to whom this is assigned in connection with other work) to check these settlement sheets, against both the mine weights and assays, and the schedules of prices arranged between the mine and the smelter. As a rule, quotations for silver, lead, zinc, copper and other metals enter into the settlements, and require checking, as do also bills of lading. Each step of the arithmetical calculation is also checked.

Jan 1, 1917