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By Ludwig Schmidt

[Steel tanks often corrode rapidly in oil fields where the gas produced with crude petroleum contains an appreciable quantity of hydrogen sulphide. In many instances working tanks have been discarded after only six months of service because of failure induced by corrosion. Aluminum has been used for some time in the fabrication of certain equipment incidental to the handling of oils containing hydrogen sulphide L; as in solution, and has exhibited no serious corrosive action. These uses indicated that aluminum tanks might be equally effective in counteracting hydrogen sulphide corrosion. Consequently, in the spring of 1928, an all-aluminum stock tank of 500 carrels capacity and a "composite" tank of equal capacity, having a steel bottom and bottom ring and an aluminum top and top ring, were placed in service on the State-Lassiter lease of the Gulf Production Co. in Crane County, Tex. These tanks were under observation for one year, the test being sponsored by the Gulf Production Co., the Aluminum Co. of America, and the Parkersburg Rig and Real Co. The results of this preliminary test sustained the belief that aluminum is highly resistant to hydrogen sulphide gas and likewise indicated the type or grade of aluminum which could be most economically used for lease tankage. However, in this preliminary test the tanks were not subjected to contact with the large quantities of highly concentrated brines such as often are associated and produced with crude oil. Therefore, it was suggested by representatives of the Aluminum Co. that additional tests be made to include production conditions in which large quantities of brine would be handled, for pact experience had known that aluminum often is susceptible to the corrosive action of brines.]

Jan 1, 1931

By Robert L. Kranz

Mining-induced microseismicity data collected by the U.S. Bureau of Mines in a hard-rock mine were analyzed for spatial and temporal patterns that might prove useful for prediction of rock bursts or assessment of rock mass damage changes. Pattern attributes described and illustrated in the previous report (part 1) were applied to the study of aftershock sequences associated with two different stopes. The aftershock sequences were spatially and temporally fractal, and the fractality was maintained for up to 16 h following a sequence progenitor. This suggests mechanical interdependency among the after-shocks. No statistical difference was found in the distributions of fractal dimensions when comparing two different stopes or when comparing aftershock sequences initiated by blasts or bumps. This suggests a lack of sensitivity to both stress perturbation mechanism and local damage states. However, differences between the two stopes were found in other sequence attributes that support inferred differences in the magnitude of stress concentrations and damage near each stope, and over time as a stope is developed.

Jan 1, 2010

1. A total of 14,413 mining operations reported employment to the Mine Safety and Health Administration (MSHA). Nearly half (48.9%) were sand and gravel operations, followed by stone (28.5%), coal (14.7%), nonmetal (5.7%), and metal mines (2.1%). 2. Mine operators reported 240,000 full-time equivalent workers1 (down 3.9% from 1999). Independent contractors reported 42,000 full-time equivalent workers working on mine property (up 8.6% from 1999). Coal operators accounted for 26.8% of reported employee hours, followed by stone operators (25.9%) and sand and gravel operators (12.1%). 3. Eighty-four (84) work-related mine fatalities occurred in 2000 compared to 90 the year before. •The mine fatality rate was 29.8 per 100,000 full-time equivalent workers compared to a fatality rate of4.6 per 100,000 employees for all private industry. •Thirty-one percent (31%) of the fatalities occurred in underground work areas, which account for only17% of total employment. •Although the largest number of fatalities (28) occurred among miners who work for coal operators, coal contractor employees had the highest fatality rate (61.1 per 100,000 full-time equivalent workers). 4.There were 10,839 nonfatal lost-time injuries reported to MSHA, occurring at a rate of 3.8 injuries per 100full-time equivalent workers, and resulting in a total of 417,918 lost workdays.2 •Among all employees,3 the highest injury rate occurred among coal operator employees (5.6 nonfatal injuries per 100 full-time equivalent workers). •The highest percentage (34.7%) of nonfatal lost-time injuries were due to handling materials (e.g., over-exertion in lifting, pulling, or pushing objects), which also accounted for the greatest percentage of lost workdays (29.3%). •Among the most frequently occurring injuries, the most severe (as measured by the median number of days lost) were associated with accidents involving falls of ground, the use of powered haulage, and slips or falls. •The most frequently reported part of the body injured was the back (22.9% of all injuries). Back injuries accounted for the highest percentage of lost workdays (21.6%). 5.Seven hundred sixty-seven (767) cases of occupational illness were reported to MSHA. •The most frequently reported illness was repetitive trauma, resulting in joint, tendon, or muscle inflammation or irritation (37.3%). •There were 155 (20.2%) illnesses reported as hearing loss. The majority (68.4%) of hearing loss cases occurred among surface workers. •Coal workers' pneumoconiosis accounted for 14.5% of reported illnesses.

May 15, 2002

By M. R. Yenchek

The U.S. Bureau of Mines has determined a method for calculating coal mine portable power cable thermal life for a specified temperature loading. This work was the culmination of a multifaceted research project involving (1) accelerated life tests of insulation and jacket materials and (2) steady-state and cyclical loading of cables. Composite Arrhenius curves were derived for common insulation and jacket materials to identify the key cable quality that precipitates thermal failure. Plots of temperature rise versus current for popular cable sizes were then referenced to develop a correspondence between cable life, based upon thermal degradation and current loading. Predictions of cable thermal life were made through integration over variable load cycles and, consequently variable operating temperatures. This procedure may have utility for both the U.S. Mine Safety and Health Administration and mining machine designers in determining the appropriate cable size for new equipment.

Jan 1, 1991

By ARCH L. FOSTER

The rapid increase in the mmber of automobiles during the last 25 years has resulted in the insistent and growing demand for better roads of more permanent construction. Some form of State license for the operation of automobiles has been in effect almost from the time of the first "self-propelled" vehicle, and some part of the revenue derived from the sale of these licenses has been applied to the maintenance and construction of roads. However, to obtain funds with which to build their present highway systems, the individual States have resorted to the taxation of gasoline. The first State to adopt a gasoline tax was Oregon, the law becoming effective February 25, 1919. By 1928, all of the States except two had levied taxes on gasoline at rates varying from 2 to 5 cents per gallon. New York and Massachusetts passed gasoline tax laws which became effective in 1929. Regulations governing the quality and the methods of handling gasoline and other petroleum products sold in the States have also been adopted by 29 States; many of these laws antedate the adoption of a gasoline tax. The variations in motor fuel speci- fications and methods of test have been pronounced in the several States. The Bureau of Mines, in making certain technical studies of the rasolines marketed throughout the United States, the results of which are reported in its semiannual motor gasoline surveys and other reports, has had occasion to obtain and compile all of the present (April 1, 1931) tax and pection laws of the several States which relate to motor fuel and other petroleum products. To facilitate the use of this material and to obviate the need in most cases of reading the complete text of the laws as published by the States, the pertinent information was arranged in tabular form for cly reference. 3 Although digests of States gasoline tax laws' are available and copies of the complete laws can be obtained from the State agancies in charge of the enforcement of gasoline tax and inspection laws, it is believed that

Jan 1, 1932

By JOE SIERAKOSKI, W. R. Hardwick

This paper , which describes mining methods and practices at the Johnson Camp copper -zinc mine , Coronado Copper & Zinc Co. , Cochise County , Ariz . , is one of a series being prepared by the Bureau of Mines on mining methods , practices , and costs in various mining districts of the United States . Johnson Camp is in the eastern foothills of the Little Dragoon Mountains in secs . 23 , 24 , 25 , and 26 , T. 15 S. , R. 22 E. ( fig . 1 ) . The mining property is in the low, rolling foothills at an altitude of slightly over 5,000 feet above sea level ( fig . 2 ) . The area is covered with scattered grass and small desert shrubs . The climate is mild , with hot summers and mild winters . The average annual precipitation is about 12 inches . The nearest surface water is the San Pedro River , some 12 miles west of the mine . The property is owned by the Coronado Copper & Zinc Co. , Los Angeles , Calif . This report gives a brief history of the property , describes the general geology of the area and of the ore deposits , outlines the methods of prospecting and exploration , and gives the methods of sampling and of estimating ore reserves . Development and stoping methods are explained . Underground transportation , ventilation , mine drainage , and safety measures also are described . The last section gives a brief description of the milling practice .

Jun 1, 1957

By Robert L. de Beauchamp

The Bureau of Mines reviewed aluminum chloride technology to determine the problems associated with its preparation from minerals, and to ascertain the best areas for research to solve these problems. Commercial AlC13 production processes are described and the ?state of the art? for the preparation of AlC13 from aluminous materials is evaluated. Areas for further research are indicated.

Jan 1, 1969

By Patricia J. Leonard - Mayer

A Bureau of Mines surface resistivity method has been used to determine the joint strike and coefficient of anisotropy of jointed , nearsurface formations at five study areas . The field studies demonstrate the use of rotated , or azimuthal , Wenner-Lee arrays for determining the strike of predominant joint sets . The results of the field studies include the following : in a formation having a predominant , vertical joint set , the maximum value of the apparent resistivity ( pa ) occurs in the same direction ( azimuth ) as the joint strike ; the polar coordinate graph of pa for such a formation is approximately elliptical ; the coefficient of anisotropy ( ^ ) can be calculated from the field data , and values of λ for jointed formations are in the same range of values reported for layered formations ; values of λ are higher at mined sites than at unmined sites . The azimuthal resistivity method and horizontal profiling were used at a site in Pennsylvania to delineate a zone of intensely jointed and fractured bedrock that provided a flow path from a surface stream to a mine . Analysis of the data has been based on a simple model of a jointed formation having a single joint set ; the success achieved to date indicates the need for a more complex model and additional field data .

Jan 1, 1983

By K. R. Van Doren

The polynomial method for estimating virial coefficients from experimental data suffers from three serious defects: (1) There is no known relationship between the polynomial coefficients and the virial coefficients, (2) the values of the estimates depend upon the degree of the polynomial and the particular set of values used for the independent variable, as well as the random errors in the dependent variable, and (3) the variances calculated for the estimates do not represent the mean square errors of estimation. Attempts to overcome these defects have thus far been unsuccessful; these attempts have also failed to account for the fact that none of the virial coefficients are uniquely determined by the values of the dependent variable for a finite set of values of the independent variable. The conclusion is that virial coefficients cannot be reliably estimated from experimental data unless additional information about the virial expansion itself, such as its rate of convergence, is available.

Jan 1, 1969

All of the coal resource in North Dakota is lignite. The lignite fields of North Dakota cover approximately 40 percent of the total area of the state, with reserves estimated to be 9.8 billion tons, two percent of the U.S. base. The first commercial coal mine in North Dakota opened in Morton County in 1873. As the railroads crossed the plains, the demand for coal increased. Coal for fuel was supplied by the state's underground mines. By 1884, North Dakota's lignite production had reached 35,000 tons. North Dakota was among the fist states to shift from underground to large-scale commercial surface coal mining. By 1927,40 percent of the total production was by surface mining, compared to 2 percent for the nation as a whole. By 1959,86 percent of the total production was by surface mining, while the national average was 22 percent. Since 1966, surface mining has been the exclusive coal production method in North Dakota. North Dakota's regulatory program received conditional approval December 15, 1980. Following approval of amendments to the program, it received full approval February 18, 1986. The Abandoned Mine Lands Program was approved December 23,1981.

Jan 1, 1992

By Arthur V. Petty

The Bureau of Mines has researched the utilization of mining and pro-cessing wastes as raw materials for the production of glass-ceramic pipe. Characterization of various wastes as to occurrence and chemical composition is reported. A computer program was developed and used to identify waste materials and mixes that would result in glass melts from which glass-ceramics could be produced after cooling and subsequent heat treatments. The production of abrasion-resistant pipe from inexpensive and readily available domestic resources could offer an economical substitute for high-alloy steels containing the critical and strategic materials cobalt and chromium.

Jan 1, 1984

By M. C. McCall

When electric current of any appreciable magnitude flows from a power line into the earth, a change sometimes takes place in the conditions of resistivity immediately surrounding the electrode or medium of contact. If the conducting medium is composed of moist earth or clay the effect is to increase rapidly the resistance. If the conducting medium is coal or a coal bed, the effect is one of slowly decreasing resistance as the coal is carbonized, If, however, the flow of current is not enough to carbonize the coal, it will dry slowly, with a resultant increase in resistance. Measuring ground resistance, or impedance, with conventional commercial ground testers does not always indicate the current that will flow in the earth circuit from a direct-current or an alternating-current power circuit. The exact reason for this has not been determined however, it is thought to be due to the comparatively minute currents used for such testing. A typical ground, tester used by the authors for this work indicated a maximum current of 25 milli-amperes. The frequency of this testing current also has an effect on the readings in all probability. While the possibilities of the effects of varying frequencies has by no means been fully explored in this investigation, there are very definite indications that the impedance of a circuit through a section of earth will vary in some inverse relationship to the frequency of the applied voltages. This is evident at ordinary power-line frequencies ns well as at higher frequencies up to 200 kilocycles, which was the highest frequency available for tests in this investigation. This report is written in the hope that it will stimulate further investigation of the possibilities suggested for communication and the development of safety devices for increased electrical safety in coal mining.

Jan 1, 1952

This report summarizes the cost of U.S, mining and milling industry compliance with the Environmental Protection Agency (EPA) interim water quality guidelines for waste discharges. Applicable excerpts from Public Law 92-500 are stated and interpreted in conjunction with the guidelines being used for implementation of the law. Over 200 U.S. Army Corps of Engineers applications for discharge permits were used to develop the quality and quantity data base needed to estimate the cost to comply with EPA guidelines, Cost of three basic treatment methods were considered: Aeration, addition of lime, and sedimentation. From the process design, cost-capacity graphs were developed to consider maximum flow rate, maxi lime addition, and average flow rates. The graphical method used in this evaluation should provide a reasonable guide to the effect of waste treatment and, therefore, Public Law 92-500 and corresponding EPA guidelines on the mineral processing industry. The cost of complying with the EPA guidelines will have the effect of prompting the mining industry to minimize the production of waste water and of undertaking some additional treatment, Two case studies are presented to illustrate efforts that might be fruitful for minimizing waste water production and for treatment of combinations of acid mine drainage, mill wastes, and metallurgical process wastes when treatment is deemed necessary.

Jan 1, 1975

By Ivor Hawkes

This report describes how longitudinal and bending stress waves in' percussive drill rods generate noise. It is shown that in practical drills the largest noise source is the bending waves, which are mainly generated because of imperfections in the piston, chuck, and drill rod alignment. Equations are presented which enable the noise spectra generated by the bending and longitudinal waves to be precisely predicted. Means for reducing the amplitude of the bending waves are discussed.

Jan 1, 1977

By K. J. Liles

The U.S. Bureau of Mines evaluated the physical properties of ceramic particulate composites made from titanium nitride (TiN), alumina (AI203), and aluminum nitride (AlN) as part of a program to meet the high-performance demands on structural materials for new and emerging technologies. Samples containing from 20 to 80 wt pct TiN were pressed and fired, and their composition, Vickers hardness, modulus of rupture (MOR), and fracture toughness were determined. X-ray diffraction and scanning electron microscope (SEM) analyses showed that, depending on the amount of TiN added, the microstructure of the samples consisted of either a titanium-aluminum-oxynitride (TiAlON) particulate in a spinel matrix or a spinel particulate in a TiAlON matrix. The best results of the physical tests were achieved on a mixture of 40 wt pct TiN, 30 wt pct A1203, and 30 wt pct AIN. Sintering aids were added in 1-and 3-mol-pct increments to the 40-30-30 mixture to determine their effect on microstructure and physical properties. Results of an analysis of variancf' on a 4 by 4 factorial analysis showed significant effects on density, MOR, and Vickers hardness.

Jan 1, 1989

By J. D. Davis

On May 15, 1936, Congress authorized the Bureau of Mines to conduct certain studies, experiments, and. investigations of subbituminous coal and lignite.4/ Appropriations were made in July 19 7, and since that date an active investigation has been underway to complete the provisions of the act. Part of the investigation has included a comprehensive survey of the known properties of the lower-rank non-coking coals, and provisions were made to obtain more data on certain varieties. In line with this plan, a typical subbituminous coal was selected for an extended series of tests in the standard. Bureau of Mines-American Gas Association unit,5/ at the Central Experiment Station. This particular noncoking coal was the first one of its rank that had been tested in the apparatus; for this reason the results are of particular interest because the testing apparatus was originally designed for use in studying the coke- and gas-making properties of coking coals. The test as described below has been developed by the Bureau of Mines since 1927 through a cooperative agreement with the American Gas Association.6/ Ninety to 180 pounds of coal is heated in a circular retort, 13 to 18 inches in diameter, at wall temperatures ranging from 500°C. to 1,110°C. in 100°C. steps. All products are collected and measured; their physical and chemical properties are then carefully determined to ascertain the gas- and coke-making properties of the coal. During the last 10 years approximately 50 representative American coals have been tested in the Bureau of Mines equipment. The results on the first 30 coals and a complete description of the test procedure are contained in a joint publication of the Bureau of Mines and the American Gas Association.7/ The remaining twenty coals have been reported in Bureau of Mines reports as Technical Papers and Bulletins.

Jan 1, 1939

By Raymond B. Ladoo

"The name bentonite has been applied to a group or series of clay-like materials characterized by an alkaline oxide and alkaline earth content of 5 to 10 per cent, fine grain Giza, high absorptive powers, and usually very strong colloidal properties.Bentonite probably represents no mineral of fixed composition, and its physical properties vary considerably. The type material from Wyoming is light yellow or greenish yellow in color, but from other localities it may be cream colored, white, gray, pink, dark brown or even black. It is exceedingly fine grained, very plastic and highly absorbent. The appearance may be dull or powdeay, but a freshly cut surface usually has a waxy luster. Some varieties have the appearance of wax and may be cut into very thin, translucent shavings. The fracture of the type material is roughly conchoidal, that of other varieties is platey and shale-like, while still others have no typical fracture. Bentonite is highly absorbent; .hen wetted it will absorb more than three times its weight or seven times its volume of water. Some varieties when wetted with water expand to more than six times (some experimenters report eight times) their original volume. The wetted material is exceedingly smooth and soft and feels like soft soap. Unlike most clays, bentonite is easily fusible at a comparatively low temperature.Under a high-power microscope bentonite seems to consist of extremely small, more or less rounded, grains of uniform size, but the texture of most varieties is so fine that individual grains can not be distinguished.Some varieties when finely ground and thoroughly agitated with water will stay in suspension indefinitely, forming a translucent gelatinous mass. The addition of small amounts of acids or sodium chloride seems to have little or no tendency to raid coagulation or settling. Other varieties of similar analysis and appearance go into suspension more easily, but settle out again in a comparatively short time. It has been suggested that the material which stays in suspension indefinitely is a true colloid of the emulsion or lyophilic type."

Oct 1, 1921

By S. M. Shelton

Preliminary work in the investigation of electrolytic manganese, as reported4/, showed promise for a practical procedure of continuous production. Laboratory work was continued in the direction of process simpliication to determine an economically feasible procedure that would require a minimum of expensive equipment for plant erection and a minimum of reagent consumption for operation. Results furnished enough evidence to indicate that modifications of the process could be made leading to simplified procedure and with no sacrifice in operating efficiency. A supply of at least 200 pounds of the metal was desired for alloy research, and it was believed worth while to utilize available facilities in a search for difficulties that were not encountered in the laboratory and that might arise in larger-scale operation. Consequently, an experimental pilot plant was erected. The plant was designed for a capacity of 15 pounds per day of metal and operated under simulated plant practice.

Jan 1, 1938

By S. M. Shelton

Preliminary work in the investigation of electrolytic manganese, as reported J, showed promise for a practical procedure of continuous production. Laboratory work was continued in the direction of process simplification to determine an economically feasible procedure that mould require a minimum of expensive equipment for plant erection and a minimum of regent consumption for operation. Results furnished enough evidence to indicate that modifications of the process could be made leading to simplified procedure and with no sacrifice in operating efficiency. A supply of at least 200 pounds of the metal was desired for alloy research, and it was believed worth Mile to utilize available facilities in a search for difficulties, that were not encountered in the laboratory and that might arise in larger-scale operation. Consequently, an experimental pilot plant was erected. The plant was designed for a capacity of 15 rounds per day of metal and operated under simulated -plant practice.

Jan 1, 1938

By Henry Kreisinger, L. P. BRECKENRIDGE, WALTER T. RAY

The investigations of fuels conducted by the technologic branch of the United States Geological Survey had their inception at the Louisiana Purchase Exposition in 1904. By an act approved Febru- ary 18, 1904, Congress authorized the work of analyzing and testing at the Louisiana Purchase Exposition the coals and lignites of the United States, under the supervision of the Director of the United States Geological Survey. An appropriation of $30,000 was made for this purpose. In the general deficiency bill dated April 27, 1904, the sum of $30,000 was added to the appropriation. To carry out these investigations the Director of the Geological Survey appointed a committee consisting of E. W. Parker, statistician of the Geological Survey; Joseph A. Holmes, State geologist of North Carolina; and Marius R. Campbell, a geologist of the Geological Survey. Under the first act authorizing this work all of the machinery and coal for the tests was to be furnished the Government free of charge. The buildings containing the testing apparatus were all paid for out of the first appropriation. After the close of the Louisiana Purchase Exposition every Congress made an appropriation for continuing these fuel tests. These subsequent appropriations permitted the purchase of appliances better adapted for the testing work.

Jan 1, 1912