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By K. K. Kelley

"INTRODUCTION The Bureau of Mines nitrogen peroxide process (2) 3/ for extracting manganese from low-grade ores is essentially a two-stage process involving the reversible reactionMnO2 + 2NO2 + 6H2O = Mn (NO3)2 . 6H2O (1).At lower temperatures this reaction proceeds to the rigth and affords a means of dissolving manganece and separating it from unreacted ore. At higher temperatures the reaction proceeds to the left and manganese dioxide is recovered and nitrogen peroxide regenerated for recycling. Evidently, therefore, the energy required for decomposition of manganous nitrate is a matter of practical importance. Similar information for certain other nitrates also is desirable beceuse the nitration step of the process produces appreciable amounts of nitrates of other metals, such as iron, aluminum, magnesium, calcium, and barium, some of which are not broken down in the evaporation and decomposition steps. Thus, a portion of the nitrogen peroxide is not directly available for recycling. Whether or not it is feasible to recover nitrogen peroxide locked in the more-stable nitrates depends partly on the energy required and the conditions necessary for their decomposition.To supply information bearing directly on these subjects, several researches were undertaken at the Pacific Experiment Station: (a) Heats of formation (24, 25, 26) of nitrates of manganese, magnesium, calcium, barium, and aluminum were measured at 298.2° K:; (b) low-temperature specific heats (23), in the range 51° to 298.2° K,, and entropies of nitrates of magnesium, calcium, barium, and aluminumm were determined; and (c) heat contents (21) above 298.2° K. of the nitrates of manganese, magnesium, calcium., and barium were measured. The results of these studies, when correlated by thermodymamic methods, permit evaluation, at any temperature of interest, of the energies required to decomposethe nitrates and furnish information concerning the equilibrium pressure temperature relationships."

Sep 1, 1944

By Robert W. Waytulonis

The Federal Bureau of Mines contacted 29 organizations--mine maintenance departments and equipment manufacturers--concerning service experience and construction of diesel exhaust-gas water scrubbers. Scrubbers are used primarily on mobile diesel-powered mining equipment subject to 30 CFR 36. Because the scrubbers cool exhaust gas and act as flame arresters, their failure would compromise safety in underground mines. Scrubber maintenance problems and frequency and modes of failure were identified, and construction materials and techniques were evaluated. Three failed scrubbers were randomly selected from two cooperating mines, and their modes of failure were determined. In conjunction with failure analyses, mine water and scrubber water solution samples were chemically analyzed to characterize corrosive properties. Sludge and mineral deposits and different types of corrosion and metal fatigue were identified as problems leading to scrubber failure. The corrosion process is explained; maintenance practices, construction materials, and manufacturing methods that could be used to reduce premature failures and allow longer effective scrubber life are identified; and basic changes in scrubber design are suggested. If type 304 stainless steel is used throughout the scrubber and regular maintenance is performed, long, dependable service can be expected. Other materials such as 304L, 316, or other more exotic steel alloys may be necessary under certain conditions.

Jan 1, 1982

By W. T. Benson

The Bureau of Mines has undertaken investigations to examine selected deposits of beryllium throughout the United States. The beryllium deposit about 6 miles southeast of Lone Pine in the Owens Valley region of Inyo County, Calif., was among those selected for study. In 1960, field work was conducted on the Inyo Beryl claim to determine the extent and character of the beryl-bearing deposit. This report describes the work that was done. In the area investigated, the beryl occurs disseminated in granite and limestone and as stringers. Apparently, the stringers are related to nearby pegmatite dikes, inasmuch as some appear to contain fine-Grained pegmatite. Granitic rocks enclose most of the stringers, which occur as fracture fillings, ranging from thin seams to 4 inches in thickness. The stringers are of muscovite, quartz, albite, and beryl. Some also include epidote and fluorite. For the most part, they are widely spaced. Therefore, mining of substantial tonnages averaging better than 0.2 percent beryl does not appear feasible.

Jan 1, 1962

By J. Mitchell Linne

The principal mineral commodity in the Orleans Mountain RARE II area (No. 35019) is gold. Gravel deposits along the Salmon River contain placer gold. Lode gold with associated silver is contained in quartz veins. Many placer mining claims have been located within the study area in the Salmon River district. Four placer patents totalling 230 acres were issued for claims on the Salmon River between Lewis Creek and Forks of Salmon. On this same reach of river, adjoining and overlapping the study area boundary, approximately 3.3 million cu yd (2.5 million cu m) of gold bearing gravel with values ranging from $0.51 to nearly $5 per cu yd (50.66 to $6.50 per cu m) (gold valued at $400 per troy oz), are contained in three placers, the Bloomer, Pot Luck, and Horn (table 1). Within the study area boundary there are approximately 950,000 cu yd (726,000 cu m) of gold bearing gravel in these three placers. These three mines yielded nearly 12,000 oz (373,000 g) of gold and more than 300 oz (25,000 g) of silver between 1872 and 1913.

Jan 1, 1982

By William A. Hustrulid

An overall summary and the individual reports of eight workshops to determine research and development needs in western mining ore presented. Problem areas are identified, and recommendations regarding priorities, funding sources, and prime movers are made. The objective of this contract was to identify research and development needs for advancing mining technology as well as health and safety measures for western U.S. Surface and underground mining. This was accomplished by convening a series of workshops where problems could be thrashed out by producers of trona, uranium, open pit copper, underground salt (from the Midwest and New York), underground metal and nonmetal, etc. In addition to problems, future priorities, funding, and the desicion as to who should be the prime mover on R & D were discussed.

Jan 1, 1976

1.1 DEVELOPMENT OF INDUCTANCE MATRICES The basic building block in this analytical work is the development of an equivalent circuit. The equivalent circuit for the cable depends on all of the distributed parameters of the cable although the series inductance and resistance are of primary importance. The cable resistances are generally available from handbooks or from cable manufacturers. On the other hand, the cable inductances are not usually available either from handbooks or from the manufacturer's published data. Thus, it is useful to summarize the derivation of the origin of the inductance matrix from basic principles. 1.1.1 Flux Around a Cylindrical Conductor The flux pattern around a cylindrical current carrying conductor can be found by using symmetry in conjunction with Ampere's Law. From symmetry it is clear that the flux lines which always close on themselves must be concentric circles. Thus, from symmetry alone one can get a qualitative picture of the magnetic field. This is shown in Fig. 1.1 where the inner circle represents the solid round conductor and the outer circle represents a flux line. The quantitative picture will now be developed using Ampere's Law.

Jan 1, 1973

By John C. Machisak

This publication, for the calendar year 1959, contains statistical data on injuries and employment pertinent to metal mines, ore-dressing plants, and primary nonferrous smelters, refineries, and reduction plants. The Bureau of Mines is authorized to request data on injuries and employment in the metal-mining industry, and the information, voluntarily submitted by the operators, contributes immeasurably to the promotion of safety in the metal-mining industry. Every effort has been made to make the annual canvass as complete as possible. The data presented are classified according to the hind of ore mined and includes information on copper, iron, lead-zinc, gold-silver lode, placer, uranium- vanadium, and miscellaneous metals. A breakdown of miscellaneous metals by commodity is shown in tables 17 and 18.

Jan 1, 1963

By Mayo D. Hersey

This problem was taken up by the Bureau of Mines as a result of the oxygen explosion at the Jefferson Physical Laboratory of Harvard University , and other similar explosions , in order to supply technical information which would serve as a basis for safety precautions in the future . At the Harvard inquiry the fact was emphasized by the Massachusetts State Chemist , Mr. Walter M. Wedger , that we do not know the limiting pressures and temperatures above which compressed oxygen and lubricating oil are capable of spontaneous explosion . The problem is also of importance to the Army and Navy and to the Bureau of Mines in connection with the hazards incurred in the use of compressed and liquified gases in the repurification of helium. In fact , the risk of fires and explosions due to traces of lubricating oil coming into contact with high pressure oxygen is of serious interest to all concerned with the manufacture and use of oxygen , a commodity which is now being produced and distributed on a rapidly increasing scale . Part of the money expended on this investigation was from Army and Navy funds . The problem was undertaken by the Bureau of Mines at the suggestion of Dr. Charles E. Munroe , Chairman of the Committee on Explosives Investigations of the National Research Council , and referred to the Pittsburgh experiment station of the bureau.

Jul 1, 1923

By Charlie Wyche

In 1980, gold, silver, and pit and quarry construction materials were the principal minerals produced in the Dominion of Fiji. The combined value of these minerals totaled some $7.2 million,2 over 85% of all mineral production, Production of cement, sand and gravel, and quarry products continued to increase, but gold and silver production from Fiji's only operating mine declined slightly from the previous year's level. Mineral exploration has been carried out by U.S., Australian, British, Canadian, West German, and South African companies since the early 1960's, and a high level of activity was maintained throughout 1980. At the end of 1980, some 40 mineral prospecting licenses covering over 4,300 square kilometers were in force, and 19 applications were under consideration by the Mineral Resources Department. Total expenditures by mining companies on land base projects exceeded $6 million in 1980.

Jan 1, 1982

By R. S. Warfield

Several reconnaissance-type surface and drill core samples of Arctic Northwestern Alaska coals were taken during the summer field seasons of 1964 and 1966 for coking studies. Surface samples were taken from the Kokolik River and the Cape Beaufort areas; core samples were obtained from the Kukpowruk River and the Cape Beaufort areas. Only one Kokolik River surface sample possessed coking properties. This sample, representing an 11.6-ft coal seam, made coke approaching metallurgical quality when a 30-pct portion of selected blending coals was added. Four Kukpowruk River core samples, each representing the same 19-to 20-ft coal seam, were all of about the same coking quality. No differences of coke quality attributable to depth of permanently frozen overburden were found, but the data confirm previously reported information that the 19- to 20-ft coal bed is a potentially satisfactory base coking coal. In the Cape Beaufort area, a core sample with appreciable coking properties was taken at depth from a coalbed determined noncoking in a surface sample.

Jan 1, 1969

By J. G. Kirby

The total number of petroleum refineries in the United States continued to decline during 1950, and according to the Bureau of Mines annual refinery capacity survey there were 357 refineries January 1, 1951, compared with 367 a year ago. The total throughput capacity increased 267,344 barrels daily during the year to 6,963,644 barrels daily as of January 1, 1951, continuing the trend of the past several years to increase the throughput capacity of the refineries and decrease the number of plants. The capacity of the average refinery to process crude oil increased during 1950 from 18,246 barrels daily to 19,506. The Indiana-Illinois refinery district accounted for 110,175 barrels, or 41 percent of the total crude-oil capacity increase, the Oklahoma-Kansas district, 17 percent, the California district, 14 percent, the East Coast district, 13 percent, and the Louisiana Gulf Coast district, 12 percent. Slight declines ill crude-oil capacity were reported in the Texas Inland, Texas Gulf Coast, New Mexico, And Appalachian refinery districts. The 160,100 barrels of additional crude-oil capacity that was building January 1, 1951, represents an increase of 10 percent over the year earlier figure. The only completely new refinery listed as under construct ion at the beginning of 1951 is located at Superior, Wisconsin. Other new construction involves enlargement of existing refineries. Plans for at least five additional new refineries are under consideration, and construction is expected to begin during the current year.

Jan 1, 1951

By K. Thirumalai

The feasibility of breaking hard rock by thermal weakening and subsequent mechanical impacting was tested, Field tests at a basalt quarry in Dresser, Wis., demonstrated that large hard-rock blocks (5 by 5 by 5 ft) could be effectively reduced in size by this method. A series of secondary breakage tests, using air-propane heating, resulted in an average heating cost of $0.36 per ton. This combination energy approach provides an alternate means of size reduction of large hard-rock boulders for quarry and for underground are chute and grizzly operations where mechanical methods, used alone, are ineffective.

Jan 1, 1975

By N. Seidle

Numerous studies conducted in the 1960's and 1970's concluded or implied (1) that a high accident rate in terms of severity and frequency exists among new (first year) operators of mine machinery equipment, and (2) that lack of experience and training is a major cause of this high accident rate. Further studies refined this premise to show that the major causes of accidents among first year operators are: (1) lack of manipulative skills; (2) failure to follow/adhere to routine procedures; and (3) failure to recognize and respond properly to hazards. This report describes the design, development, and manufacture of a shuttle car operator training system, including a program of instruction which: ? Is economically feasible. ? Addresses accident data and specific causes of accidents. ? Includes an aerospace quality simulator of sufficient fidelity to teach and develop manipulative skills, recognition of and response to hazards, and routine and emergency procedures. ? Is designed to significantly reduce the severity and frequency of accidents especially during the operator's first year. ? Is designed to significantly improve the performance of the trainee as compared to the standard learning curve. Development of the simulator produced several valuable by-products including a major state-of-the-art technological advance in visual systems for simulators, and a first-time application of (certain) advanced filming techniques to underground filming.

Jan 1, 1984

By William R. Wessels

This report describes a field survey and laboratory investigation into the causes of failure of resiliently clad screen decks applied to coal preparation plants. Blinding of screen deck perforations and delamination of the resilient cladding are studied and mechanisms responsible for these failure modes are hypothesized. A laboratory test program to simulate the mechanisms was begun and abandoned when it became apparent that meaningful test results would require a substantially redirected effort. No meaningful test data was obtained from the laboratory simulation.

Jan 1, 1982

By Forrest T. Moyer

Injury experience at metal mines and mills (excluding officeworkers) in 1964 was 60 fatal and 3,672 nonfatal disabling work injuries during an exposure time of 149 million man-hours worked. These injuries occurred at a frequency rate of 24.57 per million man-hours and had a severity rate of 3,687 days lost or charged per million man-hours. Employment at 2,363 metal mines and 291 mills, excluding officeworkers, was 68,140 men in 1964. The average number of days worked was 274 The principal cause of fatal injuries at all mines and mills was haulage accidents and in underground mines, only, was falls of ground. The principal cause of nonfatal injuries was handling material accidents. The frequency rate at metal mines and mills in 1964 was slightly below that of 1963, whereas the severity rate was higher. Injury experience at 94 primary nonferrous smelters, refineries, and reduction plants (excluding officeworkers) was 8 fatal and 999 nonfatal disabling work injuries during a worktime of 98 million man-hours worked. The combined injury-frequency rate in 1964 was 10.29 and the injury-severity rate was 1,005. The 36,956 employees worked an average of 329 days during 1964. The principal cause of injuries at these plants was handling material accidents.

Jan 1, 1968

By R. B. Anderson

SULFUR poisoning of iron catalysts in the Fischer-Tropsch synthesis was investigated at the Bureau of Mines, because synthesis gas produced from coal contains sulfur compounds. Tests of two typical iron catalysts with synthesis gas containing known concentrations of H2S were made to determine catalyst life as a function of sulfur concentration to ascertain the type of gas purification required. Fixed beds of activated steel turnings and a fused iron oxide catalyst were investigated in sulfur poisoning tests at 21.4 atmospheres with IH2+100 gas containing 6.9, 23, or 69 mg S as H2S per cubic meter (0.3, 1.0, and 3.0 gr per 100 cu. ft.). In tests of reduced catalysts at constant temperatures, more than 80 percent of the activity was lost when 0.5 mg S/g Fe was introduced. Poisoning of nitrided or carbided fused iron oxide catalysts to a given extent required more than twice as much sulfur than for the corresponding reduced catalyst. When the synthesis temperature was increased to compensate for loss in activity, tests of the fused iron oxide catalysts at constant productivity could be continued for 19 to 98 days. The tests were terminated by clogging of the reactor, presumably caused by carbon deposition. One objective of the present work was to determine if synthesis gas, purified by the Bureau of Mines' hot-potassium carbonate process for removing H2S, OOS, and CO2, is suitable for synthesis on iron catalysts. The sulfur content of the gas purified by tills process is in the range of concentrations used in the present work. In constant-productivity tests of nitrided fused iron oxide catalysts with synthesis gas containing 6.9 mg S/m3, catalyst lives are nearly long enough for serious consideration of tills mode of operation. However, factors relating to selectivity and stability of the catalyst indicate that this type of operation is impractical for a commercial process. On this basis additional gas purification, such as iron oxide boxes following a hot potassium carbonate scrubber, is desirable.

Jan 1, 1965

By Edward Keller

The work covered by this report was undertaken at the request of Dr. J. A. Holmes, late Director of the Bureau of Mines, to whom the writer had been recommended by C. W. Goodale and E. P. Mathewson, of Butte and Anaconda, Mont. The director's offer was accepted for the honor it conferred and for the useful results that might be promulgated by the work in the technical field covered. The investigation was facilitated by permission to visit various works and sometimes by contributions of important definite information on a given subject. It is therefore with pleasure that acknowledgment of courtesies is made to the following corporations and gentlemen: Anaconda Copper Mining Co., Raritan Copper Works, Baltimore Copper Smelting & Rolling Co., United States Refining Co., American Smelting & Refining Co., B. B. Thayer, A. C. Clark, A. L. Walker, William H. Peirce, E. A. Cappelen Smith, H. H. Alexander, F. C. Newton, S. Rolle, R. "V. Deacon, N. W. Pierce, O. C. Martin, C. N. Sappington, James K Thomson, W. G. Derby, and the assistants of the writer, K. 1V.McComas and W. L. Raup. In this report considerable space has been devoted to general and theoretical principles on the ground that under modern conditions the best results in any field of activity can be attained only with the aid of an adequate knowledge of the best theories underlying the practice. The diffusion of such knowledge in the field of sampling metallic metallurgical materials appears to have been quite insufficient, and it is felt that when the principles involved are once thoroughly comprehended their universal application will be appreciated, so that it will make no difference whether pig iron or gold bullion is offered for test. It may further be noted that a discussion of the theories underlying practical methods is placed under the caption "Practical Sampling," with the idea that no one can be a practical sampler unless he is capable of analyzing his methods. No attempt has been made to advocate anyone method, but it is hoped that the analyses of all of the methods in use will show where each may be correctly and safely applied. The fact that it is possible to demonstrate the theoretical correctness of several methods indicates the invalidity of the claim that any single one of them is the standard.

Jan 1, 1916

By E. B. Kester

In the commercial evaluation of coal tars, a distillation analysis properly carried out is of considerable importance. Close attention must be given to this operation in order to obtain consistent results and to secure the minimum decomposition of the tar compounds, Which in Many cases are sensitive to undue heat effects. Low-temperature tars in particular contain compounds of this nature, while in the case of tars produced at high temperatures the large proportion of pitch present has an adverse influence during a distillation. If excessive cracking takes place, the composition of the distillate will naturally vary from the normal, with the result that all the analytical criteria subsequently obtained are affected. Where tars, produced over wide ranges of carbonization temperatures are investigated as in the survey of gas, coke, and by-product making properties of American coals now being conducted at the United States Bureau of Mines Pittsburgh Experiment Station, the method of distillation must necessarily be the same for all of the tars studied. Also, it mast function equally well for both low and high temperature tar permit accurate fractionation, and reduce adventitious decomposition to a minimum. The authors are aware that certain types of distillation analysis which do not meet the above requirements may give results comparable with those of the large stills of a by-product coke-plant where one type of tar is produced. These may be simpler and shorter and entirely suitable for control work, but at the same time have little value in a fundamental investigation.

Jan 1, 1932

By R. H. Grau

Researchers from the National Institute for Occupational Safety and Health have demonstrated that mine-wide ventilation in large-opening stone mines can be improved by using low-pressure, high-volume propeller fans and constructing stoppings in key locations to direct and control airflow. In light of these findings, a comparative study was conducted to determine if a portable diesel-powered propeller fan could per-form more efficiently for dust dilution and transport than an axial vane fan for localized ventilation. The objective of this study is to evaluate both fan types for ventilation efficiency at an underground dump/crusher facility in a limestone mine. Results showed an improvement with the propeller fan to dilute both the respirable dust and the respirable silica dust around the dump/crusher facility. Overall, an average reduction of 20% in respirable dust and silica was observed at the dump/crusher location with the propeller fan.

By V. E. Edlund

As part of a research program for recovering alumina from domestic nonbauxitic resources, the Bureau of Mines investigated a lime-sinter, caustic leach technology for anorthosite. This report discusses the unit operations--feed preparation, sintering, and leaching. Acceptable pellets for the bench-scale sintering studies were prepared from mixtures of minus 200-mesh anorthosite and limestone using water alone as the pelletizing agent. Heating pellets at 1,270° to 1,360° C for periods of 0.5 to 2 hr, followed by a 15-min soaking period at 700° C and cooling to room temperature, produced a sinter that dusted to more than 90 pct minus 65 mesh. The weight ratio of limestone to anorthnsite was critical in producing sinter exhibiting good dusting and leaching characteristics. A ratio of 2.0 was optimum for the bulk samples of anorthosite and limestone used in this research. Leach solutions from lower ratio sinters were unstable; gelation became progressively more severe with higher ratio sinters. Leaching the dusted sinter with 10-pct Na2CO3 at 60° C extracted 85 to 90 pct of the alumina in a product solution containing about 50 g/l A1203. Leach residue in contact with pregnant solution tended to set up as a rigid gel as a result of cementation, comp action, and gelation. The presence of a calcium-sodium zeolite [(Cn,Na2)6?(Al2Si04)12?27-3OH20] in the ungelled residues seemed to be the main difference between gelled and ungelled residues.

Jan 1, 1982