Search Documents

By Joseph D. Davis

Selection of a suitable coal or coals for the manufacture of coke of desired quality with due consideration of the purpose for which the coke is intended requires careful thought, and often it will pay to go to consider able expense in testing such coals as may be available. In general it will always be possible to obtain a satisfactory coal or blend of coals for the particular purpose in view, but in some places the cost of transportation would be prohibitive. It may then be necessary to consider a coal or coals inferior in grade, rank, or both. At times, in fact, only one inferior coal may be available, when the problem becomes mainly one of selecting equipment and operating conditions best adapted to that coal, keeping in mind that the end product of the plant must compete with the imported product in the market the plant will serve. This applies particularly to new projects for which it is necessary to build a plant and start with a clean slate, so to speak. However, it will pay every coke-plant manager to employ a force to continually test the coals used and the coke produced to make sure that the quality is not changing appreciably. Furthermore, if the supply of coals used becomes exhausted it will be necessary to use other coals. Continual testing is particularly necessary at plants using borderline coals or blends, where slight changes in the composition or in operation of the ovens may render them dangerously expanding. In this connection it should be stated that control in the newer coke plants is considerably easier than for those built a decade or so ago, consequently in the new ovens a given operating program can be maintained more precisely. This point is important, because one of the main requirements of the coke user is uniformity in both physical and chemical characteristics. For example, any appreciable changes in the quality of coke delivered to the blast?-furnace operator will involve changes in operation if the best results are to be obtained. Such changes are expensive usually they take considerable time and involve production of inferior iron.

Jan 1, 1942

By J. C. Duchon

The U.S. Bureau of Mines is conducting human factors research for the purpose of reducing accidents and improving the person-machine interface found in surface and underground mining operations. Miners are exposed to a variety of environmental stressors, e.g., extreme heat, noise, vibration, and adverse illumination, throughout the workday. Exposure to these environmental stressors has been noted in the literature to affect performance on vigilance tasks. Since impaired performance at vigilance tasks can lead to industrial accidents, further investigation of the effects of environmental stressors on human performance is warranted. A brief description of the environmental conditions present in the mining workplace is followed by a review of experiments dealing with the effects of environmental stressors on vigilance task performance. The applicability of past research to actual mining operations is considered.

Jan 1, 1989

By Frank G. Horino

This report presents a method of utilizing the Coulomb strength criteria for estimating the strength and stability of pillars and pit slopes containing planes of weakness. It is assumed that the Coulomb theory, as a special case of the Mohr envelope, is a satisfactory first approximation of failure in uniaxial compression or triaxial loading with low lateral loads. Accepting this assumption for brittle materials, an expression for the strength decrease of rock pillars containing a plane of weakness or fracture at any angle of orientation is derived. As few as six samples (three solid cores and three fractured cores at a failure-oriented angle) are required for testing uniaxially and triaxially to statistically determine the coefficients of friction and the shear strengths of both the solid rock and the fracture plane and the range of failure angles of the fracture plane. Interpretation of the data shows that the mean normal stress and maximum shear stress technique of analyzing the data is superior for solid core and that shear and normal stress values using angles of failure should be used for fractured specimens with failure-oriented angles. Plots of either the strength or strength ratios against fracture angles obtained from oriented drill core samples give a useful first approximation of strength decrease due to fracture. Using the same test conditions for both fractured and unfractured material increases the validity of the tests.

Jan 1, 1970

By Arthur M. Hartstein

The Federal Bureau of Mines, under a contract with Ultrasystems, Inc., investigated the thermal oxidative degradation characteristics of conveyor belts used in underground mines. This included the determination of smoke evolution, glow characteristics, char yields, and the identification and quantification of all volatile decomposition products in the form of gram of specific product formed per gram of belt sample tested. In addition to these investigations, degradation studies were conducted on some pure ingredients used in conveyor-belt formulations. Three basic classes of belts were investigated: neoprene, polyvinyl chloride, and styrene-butadiene rubber compositions. The studies indicate that styrene-butadiene-based belts exhibit good flame resistance and are the least hazardous in regard to overall formation of toxic decomposition products. Under this program, thermogravimetric analysis was definitely established as a method of material differentiation.

Jan 1, 1976

By John D. Spencer

Projects aimed at achieving the least disturbance to the Nation's air, water, and land resources in the mining and utilization of coal continued to be a feature of the Bureau of Mines coal program. This reflects the current concern about damage inflicted on the environment by our growing and increasingly affluent society. Mine Health and Safety research, along with investigations related to all other aspects of coal extraction and use, also continued to be implemented and expanded.

Jan 1, 1970

By John C. Holtz

Interest in the possibility of using Diesel6/ engines for haulage power in mining and tunneling is increasing in the United States, owning largely to the reported successful use of Diesel locomotives in European coal mines and to the comparatively recent development of automotive Diesel engines in this country. The extent of this interest has been evidenced to the Bureau of Mines by numerous requests for information as to the factors that must be considered if Diesel engines are to be used safely underground.

Jan 1, 1940

By John C. Holtz

Interest in the possibility of using Diesel6/ engines for haulage power in mining and tunneling is increasing in the United States, owing largely to the reported successful use of Diesel locomotives in European coal mines and to the comparatively recent development of automotive Diesel engines in this country. The extent of this interest has been evidenced to the Bureau of Mines by numerous requsts for information as to the factors that must be considered if Diesel engines are to be used safely underground.

Jan 1, 1940

By F. Sillers, R. T. C. Rasmussen

"INTRODUCTION This is the third report of investigations by the Bureau of Mines in cooperation with industry to establish the value of electrolytic manganese in the manufacture of ferrous and nonferrous alloys. The manganese was produced by the Bureau at its Boulder City pilot plant from domestic ores and by the process developed by it. 4/ The work was done under the direction of R.S. Dean, assistant director, Bureau of Mines, and R. G. Knickerbocker, chief, metallurgical branch. The first report dealt with the use of electrolytic manganese in the manufacture of stainless steels 5/ and the second with its use in acid electric or open-hearth low- and medium-carbon steel castings. 6/The present report treats of the use of electrolytic manganese in the manufacture of low—carbon rimmed and killed steels. A résumé of these three investigations and two others appeared in the magazine STEEL. 7/ Further reports will be published as tests are completed at some 70 industrial plants. All tests were made on full—scale heats or melts, and the resultant product was processed and used commercially."

Jul 1, 1945

By G. M. Martinez

The Bureau of Mines has investigated methods for the recovery of byproduct heavy minerals from sand and gravel operations in Oregon and Washington. These heavy minerals are not currently recovered except for gold in a few areas. The recovery of byproduct heavy minerals would provide a domestic source of minerals presently imported, and a more efficient use of domestic resources would be accomplished. Samples from more than 40 locations were treated by gravity separation to yield heavy mineral concentrates (black sands). Magnetite, ilmenite, zircon, rutile, chromite, platinum-group minerals, radioactive minerals and gold were identified in the concentrates. Individual zircon, ilmenite, chromite; magnetite, and gold products were recovered from selected concentrates by low-and high-intensity magnetic, high-tension, and heavy-medium separation techniques. The recovery for the individual mineral products ranged from 67 to 95 pct.

Jan 1, 1981

By Robert L. Lappi

This report covers the final phase of a project demonstrating the economic efficiency of cross-ridge mountaintop coal mining. A demonstration mine was established at Big Wheel Gap in northeastern Tennessee. Not only was cross-ridge mining feasible for the selected site, but parallel cut methods could not be used due to a deficit in available spoil storage. Cross-ridge mining permitted coal extraction at a cost almost identical with costs simulated by computer projections using mathematical optimization techniques. No unexpected environmental problems were encountered. Volume I is accompanied by Volume II which describes the MATHMINE Mine Simulation System, software used to support the mining demonstration.

Jan 1, 1984

By F. G. Horino

This report presents the theory and design of a stiff loading machine used by the Bureau of Mines. The machine incorporates three high-strength steel columns as the restraining member in parallel with the specimen. The theory presented gives the basis of design and the dimensions of component parts of the machine. Laboratory verification of the theoretical stiffness is described using three different setups involving a hydraulic jack and spacers and confirms the stiffness calculations to within 1 percent. Experimental techniques, testing procedures, and special equipment designed for determining the complete stress-strain behavior of NX cores of both hard and soft rock are described. Typical test data are presented as force-displacement curves for two rock types, a marble and a granite.

Jan 1, 1972

The following is a Maintainability Design Checklist for coal mining equipment. The purpose of the checklist is to provide a summary of design review points for the maintainability assessment of new or existing underground equipment. It specifically focuses on the identification of equipment design features, tasks, or procedures that impact equipment downtime, repair costs, labor hours and maintainer skill level requirements. Some checklist points are general in nature. The checklist was designed to be used across all categories of underground equipment. The intent is to draw attention to design features and maintenance procedures that will increase maintainability requirements. You are encouraged to adapt this checklist to site specific or machine specific requirements by: ? Inserting specific performance criteria for various categories of maintenance tasks. For example; all hydraulic lines on a shuttle car should be replaceable in 15 minutes or 25 minutes, etc. ? Adding or deleting checklist items for different categories of equipment. You would include environmental control equipment, for example, on face equipment and not on shuttle cars or man trips. ? Adding additional checklist items based on site or equipment specific maintenance histories or experience, company maintenance standards, or other factors.

Jan 1, 2000

By Denis Dwyer

[This paper describing mining, treatment methods, and costs at Plant No. 1 of the Western Indiana, Gravel Co. at Lafayette, Ind., is one of a series on gravel and sand mining being prepared for and published by the U. S. Bureau of Mines. These papers are designed to disseminate technical information regarding the methods used. The cost tabulations represent operating expenditures only and not total costs. It is recognized that publication of total costs might in many instances cause embarrassment to individual producers, as well as to industry as a whole. On the other hand, operating costs are essential to e technical discussion and study of the methods employed, The attention of the reader is specifically called to this differentiation in order that no Misunderstanding of the scope of the cost tabulations shall ensue.]

Jan 1, 1933

Under contract from U. S. Bureau of Mines, Harza Engineering Company in cooperation with Eastern Associated Coal Corporation, conducted a ground control study of two mechanized longwall panels at the Federal Number 2 Mine. The mine is located in Northern West Virginia, and the coal is mined from the Pittsburgh Coal Seam. The prime objective of the study was to collect data which will aid in the proper selection of the longwall supports system and to control the entry caving problem. Instruments installed in the mine were borehole pressure cells, convergence recorders, roof sag recorders, horizontal roof strain indicators, differential floor movement systems, and lateral roof and floor movement systems. Instruments installed on the surface, above the instrumented longwall panels, consisted of slope indicator system, vertical bed settlement probe system and shear displacement detecting system. A comprehensive surface subsidence study was conducted in conjunction with the instrumentation. In addition to the instrumentation and monitoring, special tests were conducted to determine the bearing capacity of the roof and floor rocks, in situ modulus of coal, roof and floor rocks, and response of borehole pressure cells to ground stress. Cores of coal measure rocks were collected for the physical property tests. Face observations were made to detect various roof behavior parameters under the different jack setting pressures. This report essentially describes the instrumentation work, special tests and presents the data collected.

Jan 1, 1976

By M. A. Cook

Crude titanium metal, produced by the reduction of titanium tetrachloride with magnesium, is contaminated with some excess magnesium end adhering magnesium chloride when it is removed from the reaction pot. The method of vacuum 'purification is described in which the crude mixture is heated in a vacuum at a temperature of about 1,700° F. and the magnesium metal and chloride are volatilized away from the titanium, leaving it practically magnesium-free in a sponge-metal form. The pilot-plant equipment is described in detail, together with the technique of operation and methods of sponge recovery. Operating data is given, which compares ten 24- to 30-hour heats with ton 48-hour heats, and finally, power and labor requirements are discussed. Vacuum purification of raw titanium produced by the Kroll process has boon employed for treating of several tons of raw titanium with results for superior to those achieved by the method of leaching and grinding. The operations described, while on but little more than pilot-plant scale, indicate commercial feasibility of the process, even though it is a batch-typo operation. All equipment is either of standard manufacture or can be readily fabricated from standard materials, and operation of the units can be satisfactorily maintained by semiskilled labor.

Jan 1, 1952

By W. J. Boone

The Bureau of Mines has programmed for publication a series of Reports of Investigations of studies it has undertaken on low-temperature phase equilibria of several helium-bearing natural gases. This report is the second of a series of papers of the same general title; it is anticipated that additional reports of this series will be published. The advent of a helium conservation program and the prospect of production of helium by private industry, make it especially desirable to publish these data. This report describes phase equilibria related to a natural gas that is processed for helium at the Bureau's Exell Helium Plant (located about 35 miles north of Amarillo, Tex.). Carbon dioxide and water in the gas were removed before making the study; hence the data obtained are representative of the gas stream immediately after similar preliminary treatment in the plant process. Phase equilibrium data were obtained for conditions from -50° to -275° F. and from 100 to 500 p.s.i.a. Analyses of samples were made as follows: For a given run at a selected temperature and pressure, samples of the vapor and liquid phases were analyzed by mass spectrometer, and an additional sample of the liquid phase was analyzed for helium by means of special apparatus (7). 4

Jan 1, 1962

By Sam S. Taylor

Subsurface disposal of oil-field brines was practiced in Oklahoma on a limited scale as early as 1925. The technique of subsurface injection has been improved immensely and has been applied with varying success in many oil-producing areas in Oklahoma, and elsewhere. This method of disposal, however, is only one of several methods available to operators of oil-producing properties, but, in contrast with usual methods of handling brines on the surface it eliminates the damaging effect of mineralized water on fresh-water supplies, vegetation, and aquatic and other animal life. Other methods of brine disposal approved by regulatory agencies in some States include (1) impounding in impervious ponds and solar evaporation, (2) controlled diversion into surface waters, and (3) recovery of the mineral salts of the brine. In most States where oil is produced regulatory bodies authorize the use of one or more of these methods of brine disposal. In Oklahoma, for example, the .Oklahoma Planning and Resources Board of the Conservation Commission has been authorized4/ to adopt whatever methods or means may be necessary to prevent contamination by mineralization of all potable waters within the State.

Jan 1, 1942

By J. W. Thompson

ORES PROCESS OF ORE CONCENTRATION-PATENTABILITY. The patent issued to Sulman, Pickard, and Ballot, November 6, 1905, and assigned to Minerals Separation and Minerals Separation American Syndicate, for new and useful improvements in ore concen- tration, its object being to separate metalliferous matter from gangue by means of oils and fatty acids that have a preferential affinity for such metalliferous matter, the principal feature of which is "agitat- ing the mixture to cause the oil-coated mineral to form a froth," was clearly anticipated by other patents, and each step in the process described in the Sulman, Pickard, and Ballot patent is fully described in more than one of the prior patents, with the single exception of the reduced quantity of oil used; but the discovery that the small fraction of oil is sufficient to produce flotation of the metalliferous matter can not be made by itself or in combination, the subject of a patent. Hyde v. Minerals Separation, 214 Fed., 100, p. 109, May, 1914. ACTION FOR CONVERSION OF MINERALS. In an action by the grantor of a certain mine and mining property against his grantee to recover damages for the conversion of a quantity of ore that the grantor before the conveyance had mined and extracted from the mine and placed on the dump near the mine, the plaintiff is not entitled to recover where it appears that at the time the ore was placed on the dump the mine was owned and operated by a mining company and that at the time the ore was taken out of the mine the company had no intention of doing anything with it but simply deposited it on the dump as waste and to give an opportunity to develop the mine and get better ore to send to the smelter, and that

Jan 1, 1915

By John P. Hager

A special inlet system has been developed for a TOF mass spectrometer that allows the equilibrated high-temperature vapors from an atmospheric-pressure flow reactor to be leaked into the ion source of the mass spectrometer without undergoing any compositional changes. Using this flow reactor - mass spectrometer system and a modified transpiration system (one that allows for the carrier stream to be equilibrated with two different condensed samples) a series of fundamental vapor transport studies were undertaken. The results of these studies are summarized as follows: 1. The vapor species in equilibrium with condensed copper (I) chloride were determined to be Cu3C13, Cu4C14, and Cu5C15. The gas mixture is fifty percent tetramer near the melting point (703°K), with the percentage of tetramer decreasing with increasing temperature. The following thermodynamic results were obtained.

Jan 1, 1977

By N. A. Pace

This is one of a series of papers being published by the Federal Bureau of Mines for the dissemination of information on methods and practices used in the mining and preparation of crushed stone for market requirements. Performance in terms of units of work or tons produced per machine and per operator man-hour are given whenever that information is available. Direct operating costs are useful for comparing different methods, and are, therefore, included if possible. In addition to the factual description of equipment and methods used, it is desirable to discuss the engineering reasons for the choices that have been made. This paper is particularly concerned with the opertions at the Columbia plant of Palmetto Quarries Co. of Columbia, S.C. The plant is about one-half mile east of the Congaree River and adjacent to the southwest corner of the city of Columbia. Rail access is by the Atlantic Coast Line Railroad, and by a spur strack of the Seaboard Airline Railroad.

Jan 1, 1962