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By W. J. Fene, G. W. Grove

An important activity of the Safety Division of the Bureau of Mines , in its efforts to reduce accidents , is the safety inspection of mines . Inspections are made at the request of the operators and are not connected with the inspections by the various State departments of mines . The operating management is furnished with a confidential report of the results of the Bureau's inspections , with recommendations for elimination of the hazards found . These mine - safety inspections include a study of mining practices , conditions , and equipment and in some cases the sampling and analysis of mine air and coal dust . The Bureau of Mines has no regulatory powers , therefore the recommendations made in these reports are merely suggestions , and operators are not required to adopt them . Mine inspections are a check on safety standards , methods , and practices and are essential to any accident -prevention program . A foreman or superintendent may be sincere in his efforts to operate a mine safely and believe that he has done everything possible to attain this end . However , experience has shown that because of his familiarity with the mine and the consequent " nearness " of its various features many unsafe conditions may be , and in most cases are , overlooked ; an inspector , particularly an outsider who is trained to look for hazards , can point out the unsafe conditions overlooked by the foreman or superintendent . Some companies employ safety engineers who make regular inspections of their mines , report substandard conditions and hazards found , and make recommendations for correcting them . Unless these recommendations are carried out the inspections have little value . In making recommendations , due consideration should be given to the feasibility of carrying them out ; the management may and very often does consider a recommendation impracticable because of the

Mar 1, 1935

By A. Wahab Khair, W. M. Devilder

"This paper presents an analysis of fragment size distribution and characteristics of fracture surface in coal cutting using a rotary coal cutting simulator. Coal cutting by a drum type continuous miner was simulated in the laboratory. A series of tests along both the face and butt cleat direction of coal under different operating and in-situ conditions were performed. In each experiment the cut surface was photographed microscopically and the coal cuttings were collected and sized. Data were used to show how and to what extent various parameters effect size distribution of the coal cutting and how this correlates with the characteristics of the fracture surface. This study resulted in establishing a number of distinct correlations between the size distribution and fracture surface. These correlations were primarily based on the degree of interaction between adjacent bits and the amount of bit-coal interaction taking place on the cutting path. Some of the major results of this study are as follows:Zones of bit-coal interactions proved vital toward understanding the effect the conical bit has on the fragmentation process. This in turn led to the identification of areas which are responsible for the production of fines and generation of respirable dust.The various parameters employed in the coal cutting experiments which showed a strong effect on the coal fragment size distribution were: bit type, bit spacing, depth of cut, in-situ stresses, and cleat orientation. Bit angle and cutting head velocity exhibited the least effect and no correlation was established.From this study it is obvious that the key to achieving efficient coal fragmentation is to limit the degree of bit-coal interaction that takes place throughout the bit path while causing maximum interaction between adjacent bits. Accomplishing this not only increases the percentage of large fragments produced but limits the amount of secondary crushing that takes place in the bit path thus resulting in decreasing fines and consequently, the amount of respirable dust generated.Over 2,000 continuous mining machines (introduced in the 1950's) equipped with conical bits or point attach bits account for well over half of the United States' production from underground coal mines. Today, competition in the coal industry has increased, due mainly to coal market conditions and legal restrictions, thus placing an emphasis upon increasing production, efficiency and health/safety of the workers. Mine operators are always interested in finding the most efficient performance of continuous mining machinery to produce the largest amount of size of coal at the lowest cost. An increase of fine material sent to the cleaning plant can seriously overload the plant to the extent that plant efficiencies deteriorate significantly (1). Also, the difficulty and expense of cleaning very small particles often cannot be done economically and thus, thousands of tons of coal are sent to the refuse pile because of costly or ineffective cleaning facilities. It has been said, ""the efficient extraction of coal or rock implies breakage into a size range that contains a minimum quantity of very small sizes"" (2). All known fragmentation theories concur that more fragmentation requires more energy (3). So, the importance of reducing fines is already evident from an outlook upon efficiency.Now, let's consider another view point., duet generation."

Jun 1, 1988

By Michael J. Brnich

During the past 15 years the number of reportable mine fires has declined. A decline in the number of reportable fires is a gross indicator that allows experts to say something about the underground coal industry generally: There has been some improvement in overall mine fire preparedness. However, such an indicator is less reliable as a predictor of readiness at any particular operation. An indication of fire fighting preparedness would have to be assessed from evidence gathered at the mine site. In other words, there are two levels from which to view the problem. On a general level, there has been significant improvement in the industry's fire response capabilities over the past two decades. Specifically, however, little data has been gathered on a site-by-site basis to determine what improvements might be made on a local level. These improvements would move beyond regulatory compliance. It is expected that this manuscript, based on work conducted at an underground coal mine in the western United States, will help to focus attention on some central concerns involving this critical issue.

Jan 1, 2006

By Kenneth J. Miner

Pittsburgh bed and Lower Freeport bed coals were tested in the U.S. Bureau of Mines two-stage froth flotation pilot plant, which utilizes a new flotation process to remove pyritic sulfur. The process consists of a first-stage coal flotation step to remove coarse, free pyrite and other refuse in the tailings. The clean coal froth concentrate is then repulped and treated with a coal depressant, a pyrite collector, and a frother to selectively float the remaining pyrite in a second stage. Results in the pilot plant were excellent, comparing well with those obtained in laboratory batch tests. That is, about 70 percent of the pyrite present in the Pittsburgh bed coal and about 90 percent of the pyrite present in the Lower Freeport bed coal were removed with excellent final clean coal recoveries.

Jan 1, 1973

By R. V. Ramani, R. Bhaskar

"IntroductionThe behavior of dust clouds in mine atmospheres has been a subject of longstanding interest due to both health and safety reasons. Pioneering studies in Germany and SMRE focussed on ambient dust concentration, principally aimed at determining optimum velocities for effective dilution. A summary of studies related to this area is provided by Hall,(l) Efforts to understand dust deposition from the explosion hazard point of view led to experiments in return airways (2-4) followed by experiments in longwalls.(5) Concerted efforts, either experimental or theoretical, were not made until recently to relate ambient concentration with dust deposition in mines. In 1974 Hwang et a1 (6) developed a computer model to predict dust concentration which considered deposition-concentration relationships. Also, experimental studies involving concurrent dust deposition and ambient concentration were conducted in the U.S. by Courtney et al (7 ) in operating mines. Efforts to relate theory with experimental results have been made by Owen (8) and Hwang et al (6 ) for dust deposition. There has been limited work, however, to determine the application of the theories and assumptions from aerosol sciences for modeling dust flows in mine atmospheres. (9 ) This is the objective of the work currently underway in the Generic Technology Center on Respirable Dust since· 1983 under a project titled, ""Prediction of Ambient Dust Concentration in Mine Atmospheres."" The scope of the project activities include:1. Development of a mathematical model to predict dust deposition and concentration in mine atmospheres.2. Experimental studies on dust transport and deposition in mine airways.3. Comparison of the model results with the experimental data."

Mar 1, 1989

By Loren R. Anderson

This is an Appendix of Volume I. It contains the results of the electric cone penetrometer soundings from the first phase of the testing program.

Jan 1, 1982

By F. P. Haver

The purpose of this investigation was to determine the effect of common impurities, that is, oxygen, nitrogen, carbon, and iron, on the Brinell hardness of electrolytic titanium. On a weight basis, nitrogen had the greatest hardening effect, followed by oxygen, carbon, and iron in order. The hardening effects of oxygen and carbon were almost identical up to a concentration of approximately 0.1 percent by weight. Above this concentration, the relative hardening effect of carbon decreased rapidly, possibly because of its limited solid solubility in a-titanium. Hardness vs. composition curves for both oxygen and nitrogen were essentially straight lines over the range of Brinell hardness numbers (B.h.n.) covered in the investigation. The hardness of titanium was also determined as a function of the percentage of impurity atoms. On this basis, iron in concentrations up to 0.17 atomic percent had a greater hardening effect than either oxygen or carbon. INTRODUCTION Determination of the as-cast hardness of arc-melted titanium is a method of quality control widely used in industry. Numerous studies4/ have been made of the effect of impurities on the hardness obtained by this method. However, most of them have been based on the use of either iodide titanium or commercially pure Kroll sponge (B.h.n. >90), as a starting material.

Jan 1, 1959

By Russell R. Trengove

The Bureau of Mines developed by core drilling the Cove Meadow copper property, also known as the Patterson property, from May 6, 1949, to August 6, 1949. It is in the Cove Meadow mining district, northwestern Humboldt County, Nev., 102 miles northwest of Winnemucca. The purpose of the work was to determine possible reserves in a mineralized shear zone in andesite that has been partly explored by several surface cuts and two shallow underground workings. Production from this zone to August 1, 1,949, was 98 tons of hand-sorted copper ore assaying 5.1 percent. The development work performed by the Bureau of Mines comprised a study of the geology, mapping the area, sampling the outcrops, and exploring by diamond drilling the shear zone adjacent to the fault. Seven holes were drilled for a total of 1,246 feet. Mineral reserves indicated by the project are confined to a length of 500 feet along the strike.

Jan 1, 1950

By E. P. Youngman

Great Britain has never had a basic raining law such as is in force in most foreign countries. This lack may be due to the fact that, with the exception of gold and silver, all metals or minerals belong to the owner of the surface land. Even with respect to the precious metals, gold and silver, which are not abundant in Great Britain, the right of the Crown, though still technically acknowledged, is not always insisted unon. All other metals and minerals are vested in the ground landlord, who may sell, lease, or other¬ wise convey them. The State has little to do with the mining industry except in. regulatory and judicial matters. The Government must settle controversies and provide for easements, rights of way for railroads, roads, and canals, or, in general, effect the same control that it exercises over other industries. As mining was carried on in very early times in England, of necessity a certain legal procedure came into existence, which in effect was little more than a private contract between the owner of the mineral (whether an individual or the State) and the miner. The nature of such contracts, of course, has changed radically with the changed relations between classes, as England lias developed from the feudal into the modern State. From the medley of ancient procedure and custom, a concession system of mining in^its simplest form lias evolved. Of the earlier conditions. Van Wagenen says

Oct 1, 1931

"Introduction.The Bureau of Mines has taken up the problem of determining a method or methods whereby underground compensation insurance rates for metal-mining companies can be equalized in proportion to the underground hazards involved. This study has been started by the writer with the assistance of Mr. I. M. Wolfin* as consultant.The present paper briefly reviews the origin of accident compensation, gives a digest of State compensation laws, and describes types of insurance carriers. This will be followed by study of the basis of premium rate, risk differentials, and cost of compensation insurance to mine operators. These data will be supplemented by an analysis of the accident hazards in different mining methods and practices, and the severity and frequency of accidents classified by time lost and period of exposure to hazard, for different States, mining methods, occupations and nationalities. Attention will be given to standardized preventives for underground accidents in metal mines, and, finally, the classification of underground metal-mining hazard for workmen's compensation insurance premium rating."

Mar 1, 1924

By J. A. Ruppert, P. M. Sullivan

A study was made of filtration techniques for recovering the major part of the tin contained in iron - tin alloys known as hardhead . Special smallscale filtering apparatus and a three - stage cyclic process were developed . Eighty- seven percent of the tin contained in an alloy of 82 percent tin and 17 percent iron was recovered as pure metal by pressing at 975° C followed by a second pressing at 800 ° C and a final filtering at 250 ° C. Small amounts of Sb , Cu , and Fe impurities were removed by adding Al to the molten product and performing another filtration at 250 ° C.

Jan 1, 1964

By Lucien Eaton

This paper describing the mining practices at Mine No. 2 of the Marquette Range, Michigan is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various minim; districts of the United States. The publication, of this information should be of interest to the industry at large and the exchange of ideas thereby made possible should be of economic value to operators in all harts of the country. ACKNOWLEDGMENTS The author is indebted to the superintendent, engineer, and mining captain of the property discussed in this paper for much of the information presented. The geological classification is taken from publications of the U. S. Geological purvey.

Jan 1, 1929

By M. Clair Smith

This report is one of a series describing exploration, development, mining, and processing of mineral deposits in the United States. The reports are prepared and published by the Bureau of Mines in cooperation with various mining companies The purpose of the reports is to promote development and conservation of our natural reserves by disseminating technological information on mining and milling procedures and related practices at operating mines. Simplot Silica Products, Inc., mines and processes a friable silica sandstone. The finished products are sold for use in glass manufacture, foundries, chemicals, and special applications.

Jan 1, 1959

By Jr. Smith

The equilibrium compositions of product gases for mixtures of air with methane, propane, or ethylene at and around flame temperatures are reported. For each hydrocarbon, compositions are given for five fuel-to-air ratios--two lean, two rich, and one stoichiometric--at five pressures, from 1 to 20 atmospheres, and at an ambient temperature of 25° C.

Jan 1, 1965

By Irving Kabik

Chlorates and perchlorates, when mixed with certain reducing materials, may give a detonating explosive of considerable power. Concerning explosive chlorate mixtures, Guttman3/ states that they "have at all times fascinated inventors on account of the large amount of oxygen stored up in potassium chlorate, which can be given off so readily. When Lavoiser and Berthollet tried to make a chlorate powder in a stamp mill in 1788, they made a great show of it, and even two ladies were present. Unfortunately, after a certain amount of pounding the powder exploded and killed an official and the daughter of the Government commissary, who assisted at the experiments.***. It is interesting to observe how the same old mixtures are proposed over and over again with slight alterations only, in order to qualify for a patent. Potassium chlorate with some carbonaceous matter like charcoal, sugar, starch, glycerin, flour, or sometimes a vegetable or mineral oil and the like occurs again and again." Sprengel explosives, in which some of the undesirable sensitivity of the chlorate was minimized by coating the crystals with a liquid reducing agent, received some attention after a patent was issued to Dr. Herman Sprengel in England in 1871.4/ A somewhat similar explosive, known as Rack-a-

Jan 1, 1945

By O. C. Blade

This report on the properties of aviation gasolines and aviation jet fuels produced in the United States during 1956 was made under a cooperative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. Analytical data are presented for 120 samples of aviation gasoline and for 38 samples of aviation jet fuel. The analyses were made on samples typical of the manufacturers' 1956 production in their laboratories and the results submitted to the Bureau of Mines for compilation. The products of 20 manufacturers of aviation gasolines and of 17 producers of aviation jet fuels are represented.

Jan 1, 1957

By Harry R. Nicholls

Preliminary tests on presplitting rock in the presence of an in situ static stress field were undertaken to study the influence of a horizontal static stress field on the creation of a vertical presplit fracture plane. These tests indicated that it is easier to fracture the rock parallel to the in situ maximum compressive stress than in other directions. Instrumented shots indicate that the interaction of stress waves generated by the detonating charges is probably responsible for starting tensile fractures between shotholes and that expanding gases may propagate these initial cracks by a wedging action. The hole spacing for presplitting appears to be equal to the half wavelength of the stress wave. However, wider hole spacing appears feasible if the initial fracture is started by closer hole spacing.

Jan 1, 1966

By IRENE AITKENS

The Mining Law of 1910 , with amendments of 1914 and 1928 , is at present in force in the Dominican Republic . The first and basic mining law of the Republic was passed in 1876 , and although numerous changes and amendments have been made from time to time , the new laws and amendments thereto have not changed the original or basic law materially . However , these enactments have materially changed the legal methods governing the exploitation of the mineral resources of this country and have added new regulations and requirements to those concerning certain specific minerals , etc. The original or basic law still exists as it was first promulgated to protect the rights of the Dominican Republic itself , the rights of the landowner , and the rights of prospectors in general . The Mining Law of 1876 remained in force , without amendment , until it was superseded by the law of May 25 , 1904 , an enactment modeled after the Mexican mining law and designed especially to encourage the investment of

May 1, 1931

By G. M. Potter, F. S. Wartman, M. D. Schmid

"In matte smelting of copper it has been established that the sulphpr present will combine with copper as long as the latter is present, and that thereafter it will combine with iron. The Cu-Fe ratio in the matte is determined by the Cu-S ratio, presumably owing to the much greater affinity of copper for sulphur or, expressed thermodynamically, the greater stability of copper sulphide in contact with silicate slag. Now, the work of Fournet and of Schütz, which is quoted in many elementary metallurgical texts, indicates that manganese ranks ahead of copper in its affinity for sulphur. Hence, we might expect that manganese could be concentrated from its admixture with iron. Compounds by matte smelting, and Rotts / has patented such a process. This greater affinity of manganese or sulphur is used to advantage in iron metallurgy, also, in which it is well-known that sulphur will combine with manganese and separate from metallic iron as manganese sulphide. Manganese sulphide,however, is quite soluble in silicate slags. 5/ The loss of manganese in slag in any attempted matte smelting is therefore great.If this solubility of manganese sulphide is slag is a physical one and the reaction MnO + FeS MnS + FeOIs substantially complete, then it might be expected that the addition of copper sulphide, which is almost entirety insoluble in slag, would serve to extract the manganese sulphide with the formation of a manganese-copper matte on the other hand, if an equilibrium exists in the above reaction, a copper sulphide layer would displace that equilibrium in one direction or the other, according to whether iron sulphide or manganese sulphide were more soluble in the matter layer."

May 1, 1937

By D. L. Hollis

An arc plasma reactor, constructed and used for studying extractive metallurgical processing, was adapted by the U.S. Bureau of Mines to separate gases of different masses by using the high rate of plasma rotation. With argon and helium as input gases, peripheral reactor outlet ports had a measured average increase of about 10 pet in argon concentration relative to helium with the plasma on compared with plasma off for the same gas inlet concentrations in both cases. Approximately the same average increase in argon concentration occurred from the peripheral outlet port compared with a central outlet probe with the plasma on. There was no difference with the plasma off.

Jan 1, 2010