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By H. P. Greenwald

THOSE interested in the early developments and experiments, both in the United States and abroad, that led to modern rock dusting, will find an excellent summary in a paper by George S. Rice,13 published in 1914. The period from 1914 to 1924 was one of intensive experiment on coal-dust explosions in the United States; abroad, war activities and rehabilitation stopped this work over a large part of that decade. Amer-ican findings were published by the Bureau of Mines, particularly in Bulletins 167 and 268. It is convenient to consider that in the United States rock dusting to prevent coal-dust explosions in mines was initiated in 1924 with the publication of tentative specifications.17 This was followed in 1925 by an investigation of methods and costs12 and approval by the American Engineering Standards Committee of a Recommended American Prac-tice.18 Approximately 13 years have elapsed since this approval, and inasmuch as changes in rock-dusting practice in the United States have been evolutionary, it is necessary to consider this entire period as "recent" in some phases of the work. There have been no official changes in the Recommended American Practice since its approval. This paper reviews as briefly as possible knowledge acquired since the issue of the earlier papers mentioned, through experience in mines and experiments conducted by different organizations engaged in the pro-motion of mine safety.

Jan 1, 1938

By Read Winterburn

This study of the relationship of the accumulation and drainage of oil to the structural conditions in the Wilmington oil field is presented with the hope that the data contained herein will aid in efficient exploita-tion of other fields where similar conditions exist. It is also probable that the conditions observed in this field will enable accurate comparisons of various well-spacing programs as to efficiency of production and ultimate recovery. Formations in Wilmington Field Age Formation Thickness Lithology and Remarks Quaternary and Pleistocene. San Pedro 1000 t Fresh-water sands, gravels and clays Pliocene Upper Pico 800 t Alternating sands and silt- Stones Pliocene Middle Pico 0-200 ± Sands and siltstones Unconformity Pliocene Repetto 875-1150 Gray and green shales, silt-stones and sands at top grading to interbedded gray-ish brown shales and fine-grained sands toward bot-tom Miocene Puente 4100± Hard brown shales and sands. Sands are fine and uncon-solidated at top, becoming firmer and coarser grained toward bottom. Top por-tion contains layers of lam-inated diatomaceous shale Unconformity Schist The data included herein are not complete as to all areas and zones, being confined mostly to the area south of Anaheim Street. The sections presented are illustrative of edge-water conditions in the Terminal zone and Tar zone, but have not been extended down the structure far enough

Jan 1, 1940

By Rossiter Raymond

(Butte Meeting, August, 1913.) ON Mar. 28, 1913, the Board of Directors of the American Institute of Mining Engineers unanimously adopted the following Minute: JOHN FRITZ, one of the most distinguished of American mechanical and metallurgical engineers, won that position by the force of innate genius, indomitable industry, unstained integrity and unfailing sympathy, and generosity towards his fellow-men. Self-educated in the hard school of practice, he appreciated nevertheless the advantages of technical instruction and discussion, and evinced this appreciation both by his membership and lively interest in this and other similar societies, and by his munificent gifts to engineering education at Lehigh University, and his long and faithful service us a Trustee of that institution. . As one of the foremost of those American engineers who, through their brilliant inventions and practical skill. developed here -the modern iron blast-furnace -and rolling-mill, and introduced and perfected the Bessemer process and other improvements in the manufacture of steel, Mr. Fritz contributed mightily to the chief departments of that industrial progress which characterized the Nineteenth Century. Proud of his great achievements, we cannot but rejoice over his long and fruitful life, crowned with a peaceful death ; but our praise and thanks are mingled with sorrow, as we recall the kindly face which we shall see no more on earth, and the loyal friendship and spontaneous good-will which led the love of his generation, and the reverence of the generation which followed, to regard him universally as " Uncle John Fritz." That. summary, though only an outline, is a good portrait ; and in the present sketch, we shall do no more than supply some details of the likeness, and some elements of the background.

Jan 6, 1913

By David White

While a country is small and its coal fields are not many, it may be possible to classify its coals on some basis that avoids both overlap and inconsistency, and that may be satisfactory to the particular country, such as geographic distribution or geologic age, or regional uses. In the adjoining country, however, the coals may differ more or less; broad areas may have escaped the erasure of transition zones by erosion, and the stages of alteration of the coals may lead to a classification different from and even incompatible with that of the other country. Such classifications, developed primarily along national lines, are essentially opportunistic. Further, many even of the "use" terms that have been in more common employment with a degree of international application have lost their significance and value, due to changes in industrial methods and urban life. When the number of coal fields is large and the classification is designed to cover the coals of many countries, the groups or divisions into which the coals are integrated are found to verge one into another; and, though the main divisions may be so naturally composed and oriented that they are relatively distinct and readily separated as entities or units when taken by themselves, the sequence, through classes, groups, and subdivisions, is so complete that we find transition zones through which boundaries must be arbitrarily drawn with minute technical definition. This situation, which is conspicuously illustrated in the United States, is due to the progressive evolution of all coals, irrespective of geologic age, from peats to successively higher ranks, which, if the progressive alteration goes far enough, ends with graphite. This evolution is now firmly established and its complete acceptance is but a matter of time. A classification of all coals in all coal fields can not escape this fact and must take into account all the stages in the transformation of the fuel from rank to rank through division to division, and through group to group. The plan here outlined aims at a natural classification of coals based on their evolution from peats to graphite. As in other classifications, the differentiation of the various groups and divisions takes account of changes resulting from the progressive losses of moisture and .of oxygen of constitution; the relative conservation of carbon; the progressive increase in fixed carbon (inverse to the loss of volatile matter) in

Jan 1, 1930

By A. W. Hesse

Ventilation of all types of coal mines is fundamentally the same, in that sufficient air must be provided to properly dilute and remove dangerous and obnoxious gases and leave the oxygen content of the air not under 1 9 per cent in all places where men and animals must work. Perhaps animals should not be mentioned, as the speed of mechanical loading leaves livestock behind and outmoded. Since this paper has to do with the influence of mechanical loading equipment on ventilation, the problems will be confined to the splits and the coal-producing places of the mine. The removal of coal dust from the air, or its rapid transmission to the return air courses; the possible increase in the liberation of gases by the multiplication of cuts in the coal made during one shift or multiple shifts; and the additional electrical equipment at the faces, are the factors that cause the added importance to good ventilation in the permissible equipment area of gassy bituminous coal mines. Ventilation tor Mechanical Loading in Gassy Mines In gassy mines, the air currents must be maintained across the faces in such a way as to prevent short cuts to the returns and leaving pockets in which accumulation of gas might occur. To do this, two or more doors are required on almost every entry containing a track to the face, so located that in no event will a trip of cars block open the doors and permit the air to bypass some place or places on the air-approach side. This method frequently requires the use of unusual lengths of duplex cables to reach the mechanical equipment at the faces, particularly where the distances between parallel working places are 100 ft., as at the Nemacolin mine. Fig. I shows a pillar section being worked with mechanical loaders. This layout requires carrying the air in on the right and releasing it on the left, because the track clearance is on the right side and the line brattice is built on this side from the last crosscut to the face. Thus, the air travels to the face with greater velocity and gives more assurance of sweeping out the gas that might be exuding from the crevices of the coal. All working places, in driving through solid coal, are thus treated alike. They are all potentially gassy and must be swept clear of whatever may contaminate the air. Once the air starts into the working section, it is not released until it does a good job. Of course the volume of air must be large enough not only to dilute the gases but to carry away explosive fumes and fine coal dust quickly. Mechanical loading entails cutting and drilling of the coal during the same working period as the loading when two-shift and three-shift operations are employed, and all three processes create finely pulverized coal, which in itself is hazardous if not controlled by some means. If the ventilation is inadequate and gas accumulates, and a spark from defective electrical

Jan 1, 1942

By A. W. Hesse

Ventilation of all types of coal mines is fundamentally the same, in that sufficient air must be provided to properly dilute and remove dangerous and obnoxious gases and leave the oxygen content of the air not under 1 9 per cent in all places where men and animals must work. Perhaps animals should not be mentioned, as the speed of mechanical loading leaves livestock behind and outmoded. Since this paper has to do with the influence of mechanical loading equipment on ventilation, the problems will be confined to the splits and the coal-producing places of the mine. The removal of coal dust from the air, or its rapid transmission to the return air courses; the possible increase in the liberation of gases by the multiplication of cuts in the coal made during one shift or multiple shifts; and the additional electrical equipment at the faces, are the factors that cause the added importance to good ventilation in the permissible equipment area of gassy bituminous coal mines. Ventilation tor Mechanical Loading in Gassy Mines In gassy mines, the air currents must be maintained across the faces in such a way as to prevent short cuts to the returns and leaving pockets in which accumulation of gas might occur. To do this, two or more doors are required on almost every entry containing a track to the face, so located that in no event will a trip of cars block open the doors and permit the air to bypass some place or places on the air-approach side. This method frequently requires the use of unusual lengths of duplex cables to reach the mechanical equipment at the faces, particularly where the distances between parallel working places are 100 ft., as at the Nemacolin mine. Fig. I shows a pillar section being worked with mechanical loaders. This layout requires carrying the air in on the right and releasing it on the left, because the track clearance is on the right side and the line brattice is built on this side from the last crosscut to the face. Thus, the air travels to the face with greater velocity and gives more assurance of sweeping out the gas that might be exuding from the crevices of the coal. All working places, in driving through solid coal, are thus treated alike. They are all potentially gassy and must be swept clear of whatever may contaminate the air. Once the air starts into the working section, it is not released until it does a good job. Of course the volume of air must be large enough not only to dilute the gases but to carry away explosive fumes and fine coal dust quickly. Mechanical loading entails cutting and drilling of the coal during the same working period as the loading when two-shift and three-shift operations are employed, and all three processes create finely pulverized coal, which in itself is hazardous if not controlled by some means. If the ventilation is inadequate and gas accumulates, and a spark from defective electrical

Jan 1, 1942

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