Search Documents

By Paul M. Tyler

Graphite occurs in many places in the United States, but previous to 1914 the domestic production amounted to only 15 to 20 per cent of the natural graphite consumed in this country. Including artificial, graphite, the proportion was about 25 per cent. During the World War the production of both natural and artificial graphite increased until, in 1918 it, contributed more than one-half of the available supply, and since 1919 the proportion has not fallen below 40 per cent. Except during the war period, however, this apparently increasing independence has not been due to any large increase in production from domestic mines. It simply reflects a larger output of artificial graphite and reduced imports of Ceylon lung and chip, grades which have never been produced in substantial quantity in the United States. DOMESTIC DEPOSITS3 American graphite deposits, though numerous and often large, are characteristically low-grade. They constitute an abundant source of potential supply, but in normal times they have proved relatively costly to work, and even at the same price the various products have never been able wholly to displace certain imported qualities, notably crucible grades from Ceylon and pencil graphite from Mexico.

Jan 1, 1929

By E. H. Denny

Colorado coal-mine fatalities, which have gradually decreased since 1914, have shown a marked decline since 1924. Data on coal-mine fatalities in Colorado published by the U. S. Bureau of Mines5 indicate that the deaths per thousand 300-day workers have decreased from 9.13 in 114 to 6.14 in 1926, and that the deaths per million tons produced have decreased from 9.18 in 1914 to 4.98 in 1926. Table 1 gives fatality rates in Colorado and in the United States from 1914 to 1926 inclusive. [ ]

Jan 1, 1929

By J. R. Thoenen

During the year 1927 the Bureau of Mines, at the request of a number of quarry operators, undertook to make a study of quarry operating costs in order to determine average costs for certain operating conditions and to suggest a model cost accounting system for quarry operations. A detailed questionnaire was prepared and mailed by the bureau to all quarries on its records as employing ten or more men in 1926.

Jan 1, 1929

By D. J. Parker

Ability to signal the hoisting engineer in shaft mines is of utmost importance from the standpoint of safety and economy. The problem of signalling from the cages and especially from the moving cages has received too little attention from mine operators; however, this problem has been given considerable thought and attention by at least one large metal-mining company in Utah which has devised successful, economical, and safe systems of signalling from the cage whether it is moving or at rest. A Report of Investigations on "Methods used in Utah for signalling mine hoists from moving cages," by C. A. Allen, then a metal-mining engineer in the Bureau of Mines, was issued in June, 1920. As this report contains interesting history of systems of signalling from moving mine hoists, and describes several systems then in use, it is here quoted in full.

Jan 1, 1929

By T. W. Johnson

The Bureau of Mines, in cooperation with the Natural Gas Department of the American Gas Association, has in progress a study or the flow of natural gas through high-pressure transmission lines. A major problem of this study is to compare the deliveries calculated from the gas pipe-line flow formulas commonly used, with the metered deliveries from pipe lines in operation. In order to obtain such comparisons a series of tests has bean made on 25 operating pipe lines in Kansas, Oklahoma, Louisiana, Arkansas, Texas, and California ACKNOWLEDGEMENTS Study of the flow of natural gas through high-pressure transmission lines was made under the general supervision of H. H. Hill, former chief petroleum engineer of the Bureau of. Mines, H. C. Fowler, acting chief petroleum engineer of the Bureau of Mines, N. A. C. Smith, superintendent of the Bureau of Mines Petroleum Experiment Station at Bartlesville, Okla., and T. Brandenthaler, chief of the oil and gas action of the Bartlesville station.

Jan 1, 1929

By C. W. Owings

When explosions have occurred in mines where rock dust has been used to some extent, generally to a very limited extent, the press has immediately characterized those mines as "rock-dusted." To persons familiar with the method of rock-dusting, it is apparent that if rock-dusting is done properly, if all mine surfaces are rock-dusted to within at least 40 feet of the faces of rooms and entries, and if the incombustible content of the dust is more than 65 per cent, there is little likelihood that an explosion of coal-dust will occur. The report that an explosion has occurred in a "rock-dusted" mine immediately conveys to the mind of the alert safety advocate the information that the mine is inadequately rock-dusted or that either dust sampling of the rock-dusted surfaces has not been done or, if done, the mine has not been redusted with sufficient promptness. Rules for Collection of Samples Collection of dust samples is by no means intricate, but a few simple rules must be kept in mind if the results are to be dependable. A sample must represent the true average conditions of the dust in the section or zone in which it is taken, and therefore 'the point at which the sample is to be collected must be selected with care. During an explosion much if not all of the dust on the ribs, roof, timber, and road in the affected region is blown into the air; the sample, therefore, should contain all loose dust and material on: the surfaces to a depth of about 1 inch, if that amount is present. If there is considerable sand locally along the track, care must be taken not to include enough of this material to vitiate the sale and distort the results; however, if the sand is distributed throughout the region being sampled it should be included. Dust should not be collected from recesses in the ribs, such as hitches cut for timber, as the character of the dust in such places is often different from that on the ribs proper. Samples should not be collected at points where the dusting machine has been loaded or at a point where the machine has stopped and discharged for a longer period than at other points on the entry or in the rooms. In short, the sample must represent AVERAGE CONDITIONS, and if there is any doubt as to the character of the dust it is far better to have too much combustible matter than too much incombustible matter in the sample, as it is best to err on the side of safety if it is necessary to err.

Jan 1, 1929

By George L. Richert

The Minas de Matahambre is situated on the north coast of Cuba, in the Province of Pinar del Rio, approximately 150 miles west of Havana. This nine is the only producer of copper in Cuba, and has been worked for the past 15 years. In 1921 the property was affiliated with The American Metal Co., Ltd., and has been worked by them since that time under the direction of Mr. D. D. Homer, General Manager. Extracts from P. D. Wilson's ?Preliminary report on the geology at Minas de Matahambre? have been freely used in this report.

Jan 1, 1929

By L. C. IlsLey

In January, 1922, a conference relative to trailing cables for use with permissible mining machines was held at the Pittsburgh Experiment Station of the U. S. Bureau of Mines. At this conference it was recommended that the bureau take steps to investigate the rubber-sheathed type of cables and to bring about the establishment of a list of approved cables. Effective until such time as a complete investigation could be made, the bureau asked the several manufacturers holding approvals for mining machines to recommend cables for use with their machines. In general the cables recommended were tentatively approved. Due to the lack of available personnel, no actual tests of cables were made until mid-1927. Meanwhile a field investigation of trailing cables was made at 20 mines of three coal companies in western Pennsylvania, and samples of cables were obtained from the manufacturers for laboratory tests. Twenty-five samples of the concentric-type cable, representing the product of five manufacturers, were obtained for the tests. These cables were of four sizes, as follows: 3 cables of No. 2 B & S gage, 17 cables of No. 3 B & S gage, 3 cables of No. 4 B & S gage, and 2 cables of No. 6 B & S gage.

Jan 1, 1929

By Emory Smith

The Victorville cement plant of the Southwestern Portland Cement Co. is located about 1 mile from the city of Victorville, Calif. Two transcontinental railway systems, the Atchison, Topeka & Santa Fe, and the Southern Pacific Railroad, afford shipped facilities. The plant is modern and well kept, as the officials, especially the higher operating officials, take pride in the appearance of the place. Dust has been practically eliminated by the installation of dust collectors and wet grinding. The plant has a rated capacity of 5,000 barrels of cement daily.

Jan 1, 1929

By H. R. Pierce

A gas well has a certain definite capacity to deliver gas from the gas sand through the producing string of pipe. This capacity depends upon the pressures in the sand; that is, a well will deliver gas at a rate of flow which is determined by the formation or "shut-inn pressure in the sand and the back pressure at the face of the sand in the well. The three factors, rate of flow, formation or "shut-in" pressure, and the back pressure, for a given well, can be written into a fundamental relation which is strictly applicable only to that well. This relation can be used to determine the capacity of the well to deliver gas from any formation pressure against any back pressure held at the f ace of the sand in the well. Studies have been made of the deliveries of 400 gas wells operating under different conditions of pressure, Most of the wells which have been studied are in Osage County, Okla.; however, several representative studies have been made on wells in southern Louisiana, southern Texas, the Texas Panhandle, and West Virginia.

Jan 1, 1929

By B. Numerov

A numerical proceeding of corrections with respect to topography is worked out for places near the station and a graphical one for the remote parts of the terrain. The description is clear and very detailed. The numerical proceeding is very similar to that of the Eötvös and Schweydar methods which are in use already. In both methods the levelling is accomplished in certain circles and fixed azimuths around the station. While, in using the Eötvös method, the height differences are directly inserted into the final formulas with regard to the foot of the instrument and in case of accurate formulas derived by Schweydar the height differences are calculated with respect to the center of gravity of the attachment, Numerov introduces functions A and B, the heights, of the terrain and of the center of gravity, which are to be inserted into the formulas.

Jan 1, 1929

By H. Winkelmann

The author, who himself has worked inn the field with various types of torsion balances, expresses in the article his experience with the recently marketed Haff-Torsion-Balance. The advantages of practical work with Haff?s s torsion balance as compared with other types are mentioned. In spite of low weight and corresponding small dimensions (Model M = 23.5 kg., Model Al = 11.5 kg.) the sensitiveness is not less than that in the largest instruments. It is at 1.10-9, which is proved by calculations. A comparison with the corresponding values of other types of torsion balances (Eötvös, Askania, Gepege) is given. The mechanical features of the instrument are briefly described, and the balance is illustrated by a, cross section of it. -- W. Ayvazoglou. DETERMINATION OF THE ELEMENTS OF THE MAGNETIC AND GRAVITATIONAL FIELDS INDUCED BY AN INFINITELY LONG HOMOGENEOUS CYLINDER By G. A. Gamburzeff Gerlands Beiträge zur Geophysik, Band 19, Heft 2/3 Leipzig, 1928, pp. 210-230. The present work is a. contribution to the quastion of the reason for the magnetic and gravitational anomalies in the government of Kursk (Russia).

Jan 1, 1929

By Fred W. Snow

This paper describing the mining practices at the Magma mine, Superior, Ariz., is one of a series being prepared by the Bureau of Mines on mining prac¬tices, methods, and costs in the various mining districts in the United States. At present (1929) practically all the mineral production in the Superior district is from the Magma mine of the Magma Cooper Co. The ore is mined for its copper but contains associated silver and gold. Both direct smelting ore and ore of concentrating grade are produced. The mining methods now in use at the Magma mine were adopted or developed as knowledge was gained of the physical condition of the ore bodies and the inclosing formations; the wall rock is soft and crushed and the ore is relatively hard. In general, existing methods have been adapted to fit local conditions, but some of the mining practices used were originated at this mine. Most of the ore is mined by a combination of rill stopes and pillar stopes. The pillars are extracted by underhand mining.

Jan 1, 1929

By W. R. Crank

[Rock bursts are phenomena associated with mining operations, particularly with deep mining, although they occur throughout a wide rump, of depth, from 600 feel downward. The intensity is usually in direct proportion to the depth, varying from a loosening and sloughing off to a violent rupture, giving rise to the term, "explosive rock." The more or less violent breaking of rock in mine working, tins been variously designated as " flaking," "pressure hoists," "strain bursts," "bumps," "quakes," and "air blasts," which indicate opinions as to cause and effect. The term "air blast" lots probably beat most widely used, and naturally so, as a more or less rapid movement of air often accompanying the more violent phenomena of rock failure. Furthermore, there is an implied if not definitely expressed degree of magnitude in the action designited by a given term and in the cause and character of the action. For example. flaking, pressure bursts, and quakes are terms ranged to indicate action of increasing magnitude; and pressure bursts, strain bursts. bumps, and quakes are ranged according to the cause and character of the action.]

Jan 1, 1929

By E. J. Schneider

In view of the current interest in the constituents of low-temperature tar, the Synthesis of three known xylenols and their hydroxyacetic acid derivatives has been undertaken by the U. S. Bureau of Mines. One of these xylenols, the 1,3,2 derivative first reported by Steinkopf and Höpner,4 has been described by Brown and Branting.5 The other two derivatives, the 1,3,5 first reported by Schütz6 and the 1,2,3 reported by Steinkopf and Höpner, have now been studied in greater detail. In the present work the synthesis of 1,2,3-xylenol and 1,3,5-xylenol was repeated, with some improvements in the former. The hydroxyacetic acid derivatives were also prepared, and it was found that while the melting point of the 1,2,3 derivative agreed with that of Steinkopf and Höpner. that of the 1,3,5 derivative was found to be 111° instead of 85 to 86° as reported by Schütz, by Steinkopf, and later by Bruckner. The discrepancy between the melting-point figures is doubtless due to differences in the purity of the xylenols used in the synthesis of the acids. Schütz obtained his 1,3,5 acid by recrystallizing an impure sample obtained from a mixture of xylenols. The difficulty of obtaining a pure acid by starting with a mixture is demonstrated by Bruckner, who despite painstaking efforts was unable to obtain the pure 162.5° melting 1,2,4 isomer from a mixture that persistently melted at 138° C. Steinkopf did not repeat Schütz's work but merely used the latter's figures in compiling a table. Bruckner, on the other hand. apparently also made the acid (by an improved method), and it is difficult to explain his checking Schütz's figure, unless it is that he, too used a symmetrical xylenol obtained from a tar and not prepared synthetically, as was the one reported in this paper.

Jan 1, 1929

By A. D. Garman

This paper presents one of a series of digests of foreign mining legislation and court decisions which is being prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Bolivia has been prepared from the best available information in Washington, but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers to whom it is being referred through the courtesy of the Department of State. SYNOPSIS OF LAW All useful substances of the mineral Kingdom belong originally to the State. The soil and subsoil are regarded as two distinct parts, the latter extending indefinitely in depth (Art. 2). The subsoil is under the dominion of the State, which may either abandon it to common use, grant it gratuitously to the owner of the soil, or alienate it, in return for an annual fee, to any individual or association that applies for it. (Art. 1-3.)

Jan 1, 1929

By E. D. Eastman

The basic character of the free energy r data relating to water and the oxides of carbon makes it desirable that the most representative values that can be obtained should be constantly available. The calculations of Lewis and Randall3 retain much of their of original value, but appear to require some modification in the light of more recent work. This paper has been written to incorporate the newer information and to present some estimate of the reliability of the resulting figures. The data upon which the calculations are mainly based are, for these substances, the equilibrium constants of the various reactions involved. The original work relating to these equilibria has, been reviewed and, where possible, weighted to correspond with its probable reliability. The differences in the results of the present from the earlier calculations are partly the consequence of this appraisal and partly of the inclusion of more extensive data, as will be indicated in detail in the succeeding sections.

Jan 1, 1929

By Roy H. Poston

This paper sets forth the mode of ore occurrence, characteristics of ore and country rocks, methods of exploration, development, and. ore extraction, and the costs of underground operation at No. 8 mine of the St. Louis Smelting and Refining Works of the National Lead Co. located near the southern extremity of the Southeast Missouri lead district. The author acknowledges the assistance of E. T. Campbell, geologist, in the preparation of the paragraphs on the geology of the ores. HISTORY The first record of mining in St. Francois County, Mo., concerns more or less shallow semisurface "diggings" which were worked about the year 174-2. In 1864, however, the discovery of the disseminated deposits, the present source of lead, was made on property near the town of Bone Terre. Winslow has estimated the lead-ore production in this county prior to 1869 to be 59,526 tons.3

Jan 1, 1929

By G. L. Oldright

This paper is the fourth of a series of preliminary papers on smelting in the lead blast furnace.4 The objects of this investigation are to determine the conditions obtaining within the blast furnace by direct experimentation and to correlate these conditions with operating factors, furnace behavior, and metallurgical losses. ACKNOWLEDGMENTS The authors wish to express their appreciation to the management of the International Smelting Co. at Tooele, Utah, for their whole-hearted cooperation in this investigation.

Jan 1, 1929

By Paul M. Tyler

Graphite is an essential war mineral and for that reason has received much attention from the standpoint of national defense. During the World War the situation with respect to graphite supplies, though it never became acute, caused considerable concern. Even in peace time, however, graphite has aroused more interest than the actual size of the industry seems to warrant. Despite this wide interest the facts of the industry do not seem to be generally known. Often there has been an almost total disregard of the essential' economic and technical problems involved. Long ago Bastin3 made the following statement; in a Government' report: "To-day there are more abandoned mines and mills in the United States than the number in operation * * *. In the number of times' some of these properties have changed hands in the course of a few years, there is a record of misrepresentation and disappointment that can hardly be equaled in any other branch of mining; and many properties have been notoriously associated with stock manipulation of doubtful character." According to one authority fully 600 graphite mines have failed in the United States, and the record shows that of all these properties scarcely a score have ever succeeded in operating for as much as a year or two. More than 40 mines have been worked at various times in the State of New York alone and at least that many in Alabama. Throughout the country, in fact, there are scarcely a dozen States in which efforts have not been made at some time to exploit graphite deposits. At the present time the list of mines that can be classed as at all active is reduced to less than ten. Failures inevitably occur in all lands of mining, but the disheartening feature of the record of graphite mining in this country is that so few ventures have even paid back the money put into them and. that none has been a conspicuous success.

Jan 1, 1929