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By AIME AIME

STRIP coal mining in the United States has-become noted for its massive equipment, especially its power shovels. Notable among the latest examples of this trend is the Bobolink mine of the Binkley Mining Co., at Seeleyville, Ind.,. eight miles from Terre Haute. This is only one of the Binkley company's operating properties; in all, the company owns or controls 26 mines, in fourteen seams. The Bobolink, however, is the largest strip mine in America and probably also in the world. It has an estimated life of fifteen years. The shovel used to strip the over¬burden is electrically operated, of Bucyrus-Erie make, and was. shipped to the property for assembling, a job

Jan 1, 1936

By C. E. Julihn

In the past few years the advance of the Sunshine mine to national prominence as the chief silver-producing mine of the United States has revived interest in the area in which it is situated. Although this area lies between the great lead-Zinc-silver mines at Kellogg and those in the vicinity of Burke and Mullan it was generally presumed to be almost barren, as little ore had been found there until substantial ore bodies were developed on deep levels of the Sunshine mine. In early days it was called the "dry belt" because its ores were siliceous and contained little lead; but the classification of ores in smelting as wet or dry, although once customary, has long been obsolete The area will therefore be referred to in this paper as the silver belt of the Coeur d'Alene district because the value of its ore is due chiefly to silver, the current production of which is large, providing over 60 percent of the silver output of Idaho. Silver Belt - Its Limits and Character With a daily production of half a ten of silver or more from the Sunshine mine, the silver belt has become the scene of extensive exploration at many properties, and the outlook for its future seems promising enough to warrant the lively interest now being displayed in the area by the public.

Jan 1, 1936

By F. S. Crawford

The average visitor to a large electric-shovel operation may wonder how electric power can be treated as carelessly as apparently it is in open-pit mining, and how the mining company can string it carelessly along the ground in great, black, hoselike cables, whereas the power company, which has learned to respect his deadly agency, keeps power lines far out of reach. This is explained by the fact that this particular kind of application of power to moving machinery requires the use of trailing cable instead of the more permanent type of construction that permits a moving contact, such as a trolley. The cables are designed to insulate fully the enclosed power lines against damage and loss of current; and employees are taught to handle them carefully, although engineers are not satisfied that the trailing cable is foolproof and are seeking constantly to improve methods and equipment to insure greater safety. In some sections they rely mainly on the construction of the cable and perfection of equipment, while in others additional precautions are taken, such as handling the cable with rubber gloves, slings, tongs, or loops. In some sections no temporary repairs are made to cables, while in others such repairs are made and later are vulcanized in the shop. At some operations the cycle of shovel duties is arranged so that cables are very seldom exposed to flying rock fragments while at others this exposure appears to be unavoidable. Methods of fastening the cable to the shovel frame and transporting the loose cable vary. Inspection and care of the cable are important in insuring its safety and durability. A limited amount of information was obtained by field engineers of the United States Bureau of lines from operators in various parts of the United States, as methods of handling electric-shovel operations differ with the districts; practices followed and equipment used in these districts are described in this circular.

Jan 1, 1936

By G. C. Bateman

THE cause of silicosis and its prevention have held the attention of medical men and mine operators for many years and at the present rime the study of this disease is more than ever to the fore, even though a considerable abatement in the incidence of silicosis has been noted of late. This abatement is due to individual and collective efforts. The Industry is keenly alive to the situation and much research is being carried on. Silica dust is assumed to be a contributing factor in the cause of silicosis. How it acts progressively in the early silicoric is nor fully understood. As the study advances, more effective measures of control may be evolved. At present the Industry has three known methods of reducing the incidence: 1. By thorough X-ray examination of all applicants, with special reference to chest conditions. Those who are considered to be susceptible to the disease are prevented from entering the industry. 2. Thorough ventilation of the mine. 3. Control of tuberculosis in mining centres and removal of miners when first symptoms of tuberculosis become apparent. In 1934, the Ontario Mining Association formed a Committee, known as the Technical Silicosis Research Committee, to study and supervise work on problems related to silicosis. This Committee obtained the full-rime services of a mining engineer to carry our research work at the mines in the Province of Ontario. The Ontario Mining Association has also provided funds for the purpose of carrying on research work along pathological and biological lines. This work is being done in the Department of Medical Research of the University of Toronto, in the Banting Institute, under the supervision of Sir Frederick Banting. The Silicosis Committee work in full cooperation with the doctors in the Banting Institute and provide material from the mines for the it use.

Jan 1, 1936

By ALICE V. Petar

Through the courtesy of the State Department, the Bureau of Mines has received a compreensive report on the jede industry of Burma, pre- pared by American Consul Winfield H. Scott, Rangoon, Burza. This mater- ial is the main basis for the present circular, although free use also has been made of reports on the jede industry in China and Germany by consular officers in those countries, to whom footnote credit is given. The word "jade" is said to be derived from the Spanish "piedra de ijada" (hijada) meaning, literally, "stone of the side," as jade was supposed to cure pains in the side; nephrite (a jade mineral) was named from the Greek word meaning kidney, because it was formerly warn as a re- medy for kidney diseases. To the Burmeso, jade is known as "Kyauksein," or green stone, and to the Chinese, all varieties of the material are referred to as "Yu" or "Yu-chi", According to Confucius, jade was symbolical of. justice, harmony, intelligence, and humanity, and the Chinese of today believe that by using ornaments made of this stone, the wearer is. protected from the "evil eye" as well as from diser.se. Ornaments of carved jade were known to the ancient civilizations of Mexico and Peru and to the peoples of other sections. of Central and South America, Jade ornaments also have been found in the lake dwellings of Switzerland and in Crete; thile in China, as far back as the Chou dynasty (B. C. 1122 B. C. 255) it was used in the production of various classes of precious vessels and as insignia of rank.

Jan 1, 1936

By Alicia O&apos, Overbeck, Reardon

DIFFIDENTLY, because don'ts are rarely greeted with cheers; humbly, because I, myself, have never lined up with the irreproachables, I venture on the subject of manners for the mining camp matron. Mining camps can be divided roughly into two types-the large, opulent settlement that blooms like the rose about a strong mine in full operation; and the puny group of adobe huts, or calamina shacks, or even canvas tents flung down in the wilderness to shelter the gay pioneers of a shining prospect or the shattered survivors of a lost hope. Of the first, I know nothing; but in the second, I have spent some of my best years, and from its curious code of morals and manners, its comic hates and its unreasoning loves, its high impatience and its engulfing kindness, I have charted the narrow .and pitted path which must be trod by the woman who would success¬fully live therein.

Jan 1, 1936

By D. Harrington

In general, mining is carried on underground, that is, in confined places where it is difficult to obtain adequate lighting and frequently in rock strata requiring much care to prevent caving. Moreover, explosives must be used in mining with the numerous hazards associated with them, and some mines give off explosive or irrespirable gases; also, ma- chinery must be used, usually under conditions much more hazardous than on the surface. These and many other considerations cause mining to be probably the most hazardous occupation in which large numbers of our fellow countrymen are employed. Prevention of accidents in the mining industry is far more complicated than in surface industrial work, even of the more hazardous types, because the different elements that enter into possible accident occurrence are ascertained more readily above ground and suitable action can be taken against them; moreover, errors in connection with prevention of accidents in surface industrial work usually affect only one or, possibly, a few persons, while in zines one human error may readily cause an explosion or other untoward occurrence resulting in the death of scores or even hundreds of persons. This difficulty in the prevention of accidents in and around mines is well-known, and most countries and States have regulations to guard the safety and, to a much smaller extent, the health of workers in mining and allied industries. In general, the State laws and regu- lations regarding the welfare of mine workers are merely a skeletonized outline of some more or less fundamental minimum requirements and are far too general to do much more than suggest some procedure which may or may not be safe or healthful. Most of them are grotesquely out-of-date as applied to present-day conditions, and none of them is adequate to protect life, limb, health, or property. Unquestionably, there is great need for a closer correlation of the laws and regulations of the various States with regard to safety in the mining and allied industries, and while mining conditions vary far too much for a standardized mine safety law applicable to all of the States, on the other hand there are numerous standard and fairly fundamental safety pro- visions which apply to all mines and which should be embodied in the mining codes of all States. Undoubtedly, these standardized safety requirements would be opposed by a consider- able part of the industry, but the ultimate effect would be beneficial to the owners, work- ers, and the general public. For many years progressive mining companies in the United States have not been satisfied to operate only within the meager safety requirements of the State laws or regulations and have adopted additional and far more effective safety procedure of their own, although com- plying also with the State laws and regulations. As a result of this forward-locking policy, zany of these companies have made astonishing progress in the reduction of accidents.

Dec 1, 1935

By L. E. Geyer, W. W. Adams, M. G. Parry

"More than 73 million pounds of rock dust were used by the bituminous-coal-mining companies in the United States during 1930 to present or limit loss of life and destruction of property from explosions of gas and coal dust in underground mining operations, according to statistics compiled by the United States Bureau of Mines from reports furnished by mine operators. The mines using rock dust produced 65. 691, 753 tons of coal during the year, more than 30 percent of the total production of bituminous coal from underground mines in the United States that year. Although only 382 out of a total of 5,629 active underground bituminous mines applied rock dust to underground working as a precaution against explosions, they were chiefly the larger producing mines, employing 25.4 percent of all of the underground bitumious mine workers in the United States and accounting for 27.4 percent of the total number of man-hours worked underground at bituminous mines.a summary of the reports for the 382 mines using rock dust showed a total production of 96,691,755 tons of bituminous coal, 89,503 men employed underground, and 129,718,965 man-hours worked by the underground employees. (See tables 1 and 2.) These mines averaged 8.76 pounds of rock dust per ton of coal shown by reports from 385 mines using rock dust in 1932 (See table 3.)"

Nov 1, 1935

By V. E. Erwin, W. W. Adams

"Production of explosives for industrial use in,the United States during 1934 continued the upward trend begun in 1933 from the low-level output of 1932, and the output in 1934 was only slightly less than in 1931.Reports to the United Stated Bureau of Mines from companies engaged in the manufacture of industrial explosives showed that the quantity of explosives manufactured in the United States and sold during 1934 for use within the various States was 314,767,922 pounds - 23 percent more than in 1931.Production during 1934 included 39,207,845 pounds of permissible explosives 5 206,625,027 pounds of high explosives other than permissibles, and,68,935,050 pounds of black blasting powder of which 37,192,700 pounds were in granular form and 31,742,350 pounds in pellet form. These figures represent an increase over 1933 of 15.6 percent for permissible explosives, 30.9 percent for other high explosive, and 7.4 percent for black powder.Coal-mining operations were the chief consumers of permissible explosives; 99 percent of the total output in 1934 was used, in coal mines. The proportion used by bituminous mines was 59 percent and by anthracite mines 40 percent. Coal mining was likewise the principal consumer of black blasting powder, taking 88 percent of the total sales during 1934; of this proportion, bituminous mines received 78 percent and anthracite mines between 9 and 10 percent. Consumers of high explosives other than permissibles were more varied; the reports showed that 11 percent of the total quantity sold was for coal mining, 22 percent for metal mining, 17 percent for quarrying and nonmetallic-mineral mining, 46 percent for railway and other construction work, and 4 percent for all other purposes."

Oct 1, 1935

By Carlton E. Brown, William P. Yant

"INTRODUCTION Direct visual microscopic determination of particle-size distribution and number concentration of atmospheric dust is time-consuming and trying to the eyes. By using the microscope to project images of the particles at high magnification onto a screen much of the eyestrain can be eliminated and particle-size distribution results obtained with less effort and at a considerable saving in time. It also permits simultaneous observation of the images by more than one person. Microprojection requires no more skill and very little more apparatus than is required in the use of the microscope. Anyone familiar with the microscope should be able to obtain as perfect images on the projection screen as in direct visual microscopy since the same laws and limitationsThe theory and practice of microprojection are described in detail in texts. 5/6/ The procedure has been used and found to be satisfactory for measuring the particle-size distribution of sub-sieve-size substances, such as pigments and powder 7/8/ in the same size range as that of atmospheric dust. The Bureau of Mines has used the microprojector and found it to be quite satisfactory for (1) the determination of the number concentration of atmospheric dust R.I. 3289 in samples collected by the Owens jet dust counter; (2) particle-size distribution in samples of atmospheric dust collected by the Owens jet dust counter and by the electric precipitator; and (3) the particle-size distribution of dusts, blood cells, bacteria, and pollen. Work is in progress at this Bureau on the use of the microprojector in counting impinger samples. The use of different kinds of illumination, such as reflected (dark field), polarized, monochromatic, and ultraviolet, in the projection of images of atmospheric dust particles is being considered."

Oct 1, 1935

By Arthur L. Crawford, R. E. Head, Fred E. Thackwell, A. Lee Christensen

"The data in this report are the result of a detailed, microscopic study of composite samples of mill products collected over a 14 day period. The samples were collected and assembled under the direction of W. R. Lindsay, superintendent of the Anyox plant, and are fairly representative of the heads, middlings, tailings, and products peculiar to the scheme of concentration practiced at Anyox in 1930.The work was done in the Cooperative Microscopic Laboratory at Salt Lake City, Utah. This laboratory was equipped by the mine and mill operators of the Salt Lake Valley and functioned under a cooperative agreement between the United States Bureau of Mines the University of Utah. This is the fourth of a series of papers 6/ dealing with a microscopic study of mill products."

Oct 1, 1935

By J. R. Thoenen

This circular is part IV of the third paper (entitled "Sand and Gravel Excavation") of a series summarizing the technical problems involved in the production and preparation of sand and gravel. Part I discussed the use of power shovels, draglines, and excavator cranes; part II discussed the use of power scrapers, slackline cableway excavators and hydraulic monitors; and part III discussed the use of hydraulic, clamshell, ladder, and dipper dredges. This circular discusses haulage equipment in general, particularly the use of industrial cars with locomotives or hoists as the motive power. Part V, to follow, will discuss the use of other types of haulage equipment.

Oct 1, 1935

By M. J. Ankeny, J. J. Forbes

Several sets of questions and answers on the fundamentals of first aid to the injured, based on the Manual of First-Aid Instruction of the United States Bureau of Mines, are now in use in various parts of the United States. Persons experienced in first-aid instruction believe that a standardized set of questions and answers will assist materially in preparing men for examin- ations conducted by the Bureau for first-aid certificates. Inquiries as to whether a set of standardized questions and answers is available have been made frequently by those training men for the Bureau of Mines examination for certificates. It is believed that the following list of 171 questions and answers com- piled directly from the manual will be useful to company officials and em- ployees who are engaged in cooperative first-aid training to qualify for Bureau of Mines certificates. The list may also be used by field men of the Bureau in training instructors preparatory to a cooperative training campaign and in examining classes or individuals for first-aid certificates. The page references in parentheses refer to pages in the Manual of First-Aid Instruction.

Oct 1, 1935

By J. W. JOYCE

The Geophysical section of the United States Bureau of Mines has received many inquiries regarding the application of geophysical methods to the location of small, buried metallic objects. The object of this paper is fourfold: (1) To sketch as briefly and non- technically as possible the principles underlying the operation of several elec- trical geophysical methods of prospecting applicable to the finding of small, buried metallic objects; (2) to point out the possibilities and limitations of these methods; (3) to present, whenever possible, data showing actual results obtained from their use; and (4) to enumerate and describe methods that lack scientific background or foundation.

Oct 1, 1935

By H. H. Schrenk, W. P. Yant, P. H. Mautz

"In a study of the chemistry and pathology of chronic benzene poisoning, which was conducted cooperatively by the United. States Bureau of Mines, the Barrett Co., and the producers of benzene, it was necessary to make quantitative determinatious of the abzorption, distribution, and: fate of benzene in the organism. Although methods for determining benzene in relatively large amounts were available no satisfactory method was found for removing and determining the small amounts that are present in the tissues or excretions after exposure to conditions which ultimately cause chronic poisoning. This no doubt accounts for the lack of information in the literature on this particular phase of benzene poisoning.The writers have found in work that will be described in a subsequent publication that the amounts of benzene present in the tissues and excretions under conditions of exposure which produce chronic benzene poisoning arc of the order of a fraction to a few milligrams per 100 grams of tissue. This report describes a method developed and found satisfactory for these determina¬tions.RÉSUMÉ OF PERVIOUS METHODSA method for the determination of benzene in tissue was developed by Joachimoglu. 5 In the Joachimoglu procedure the ground organs are mixed with water and acidified with diluted sulphuzic acid, and the benzene is distilled into a receiver containing carbon tetrachloride. The benzene is nitrated in the carbon tetrachloride, the carbon tetrachloride evaporated, the acid mix¬ture neutralized, and the dinitrobenzene extracted with ether. After removal of the ether the dinitrobeuzene is determined gravimetrically. Joachimoglu reports that this method is about 55 to 60 percent quantitative."

Aug 1, 1935

"At the request of the Anthracite Institute, the United States Bureau of Mines during February, March, and April 1935, made a field survey of commercial anthracite shipped from collieries scattered throughout the Anthracite regions. In all, 268 samples were taken at 41 breakers from Carbondale at the northern end of the field to Pottsville at the south. These collieries ship approximately 50 percent of the industry’s total production. The geographical distribution of the breakers sampled was as nearly as practicable in proportion to the tonnage of the companies from each region cooperating in the plan.The following are the weighted average analyses, by sizes, of the samples taken in this survey;"

Jul 1, 1935

By W. E. Miller, W. P. Yant, G. W. Jones, R. E. Kennedy

"The determinations of the limits of inflamability of diethyl ether and ethylene in air described in this report were made primarily for comparison with similar determination of other compounds in the same apparatus and by the same laboratory technic. The experimental procedure and the results obtained differ somewhat from those of other investigations. The work also included determinations of the limits of inflamability of these combustibles in oxygen The investigation,was conducted at the Pittsburgh Experiment Station of the United States Bureau of Mines in cooperation with Merck & Co., Inc. LIMITS OF IMFLAMIABILITY OF DIETHYL ETHER-AIR MIXTURESThe limits of inflamability if diethyl ether in air were determined for upward propagation of flame in an upright, closed 8-liter, cylindrical iron bomb 10.2 cm in inside diameter and 96.5 cm in length. This bomb been described in a previous publication. 6Two brands of diethyl ether were used, one a C. P. sulphuric ether manufactured by Baker & Adamson, and,the other Merck & Co. product manufactured for anaesthesia and containing about 3.5 percent of ether alcohol."

Jul 1, 1935

By L. B. Berger, W. P. Yant, J. B. Littlefield

"INTRODUCTION Hydrogen sulphide (H2S) is one of the most toxic industrial gases and of relatively wide occurrence in industry. Among its common industrial occurrences are, in the production and refining of high-sulphur petroleum, in natural gases, in gypsum and sulphur mining, in rock strata and underground waters (where it is encountered in tunneling and caisson work) in blasting with black powder and in blasting high-sulphide ores with other explosives, in gas manufacture, in the carbonization of coal, and in the manufacture of chemicals.The usual methods of detection, other than by the sense of smell, which is lost in 2 to 15 minutes' exposure to 0.010. to 0.015 percent of this gas, 5/ either are too cumbersome for frequent and rapid analyses or, like the wet lead acetate paper test, afford only qualitative results. A qaantitative determination usually involves the use of solutions, bubblers, flowmeters, standard solutions, burettes, and indicators manipulated by trained technical men. All apparatus and methods in common laboratory use are, in general, unsuitable for the field.The physiological response attending exposure to various Concentrations of hydrogen sulphide in air, is as follows, in percent by volume 6/:0.005 to 0.010: Subacute poisoning - slight symptoms, such as mild conjunctivitis and respiratory-tract irritation after 1-hour exposure."

Jun 1, 1935

By W. W. Adams, T. D. Lawrence

"The National Safety Competition covering the calendar year 1934 was the tenth yearly safety contest conducted by the United States Bureau of Mines. Participating in the competition were 334 mines and quarries in 38 States. Five mining or quarrying companies, each the leader in its group for having established the best safety record during the year, were awarded the national safety trophies ""Sentinels of Safety.""Since these annual contests were begun 10 years ago by the United States Bureau of Mines the scope of the competition has been broadened materially, both as to the number of plants participating and as to the number of man-hours of exposure to accident hazards. Moreover, marked progress in the prevention of accidents has been achieved, as is indicated by an almost constant downward course in toe accident-frequency rates for the contest group as a whole during the past 10 years. On the other hand, the accident-severity rates for the group showed an upward trend during the first part of the decade and a downward trend during the latter part of the period except in 1930 and 1934; in each of those years a disastrous explosion with abnormally heavy loss of life occurred at the property of one of the participating companies.Because of the abnormal nature of the major disaster in a bituminous-coal mine in 1930 and 1934 the accident-severity rates for the bituminous group for those years are not strictly comparable with the rates for other years. The rates for bituminous mines for 1934 in the present report have therefore been computed on two bases; first, to exclude the record of the company that suffered the disastrous explosion and, second, to include the record of this company. The first rate represents the normal experience of the bituminous coal companies unaffected by the disaster and is therefore more indicative of the real trend of the accident rates for this class of mines from year to year. The latter rate shows the actual experience of all bituminous mines in 1934. The report of the competition of 1930 likewise showed the rates for the bituminous group as computed both with and without the disaster that occurred that year.The National Safety Competition is conducted by the United States Bureau of Mines in the interest of safety in the mining and quarrying industries. This object is accomplished directly through the efforts of the competing companies and their employees to win first place in the competition and thereupon receive well-merited and national recognition for their achievement. Indirectly the purpose of the contest is accomplished through studies by the Bureau of Mines of the facts contained in the accident reports which the competing companies furnish to the Bureau to enable the Bureau to compute the accident rates that are the basis for determining the winners of the contest."

Jun 1, 1935

By M. D. Heresy, H. F. Coward

"Whenever a manometer has been used for recording explosion pressures it has been calibrated under a series of static pressures. Whether the readings taken during the rapidly changing pressures of an explosion (dynamic pressures) truly represent the actual pressures therefore is an open question. The authors had hoped to solve this problem by conducting the calibration with the aid of known pressures, applied at about the ammo rate as in an explosion, for example, by means of a cylinder and piston, the piston being driven in by an eccentric cam at a rate which would be determined accurately by the shape and rate of revolution of the cam. If the rate of compression were great enough, then the pressure in the cylinder (to which the manometer is attached) could be calculated from the laws of adiabatic changes of pressure and volume. It seems highly probably, however, from H. T. Tizard's observations on pressure changes in a cylinder during rapid compression (55) 4/ that there is much heat loss, therefore pressure loss, in the very small interval of time during compression; although Tizard was able to estimate the amount thereof, he did so only by relying on his nanometer, which is exactly the procedure that the authors challenge on the grounds that the manometer was not standardized under the conditions of its use. Hence the authors were driven from this scheme of calibration to another, namely, comparing records of ono and the same explosion taken simultaneously on several instruments of as varied a type as possible. If 2 of a number of instruments agree, perhaps both are accurate; if 3 agree, probably each of the 3 is accurate; if 4 agree, it is almost certain each of the 4 is accurate.There was a second objective in the present work. If the Bureau of Mines and the B.C.D. (British Coal Dust) manometers differ in their records, then from a sufficiently comprehensive series of experiments it may be possible to coordinate the extensive results already obtained at the American and British stations.Thirdly, it was hoped to learn which is the best available instrument for observing the pressures of coal-dust and as explosions and, if possible, to indicate means for improvement in manometry."

May 1, 1935