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By F. M. Goodwin, John Campbell, G. W. Jones

"INTRODUCTION In cooperation with the Boston Edison Co. and the Boston Consolidated Gas Co. of Boston, Mass., a survey has been conducted continuously since 1929 by the Bureau of Mines to determine the general hazards of combustible gases and vapors in manholes of the Boston Edison Co. The New England Telephone & Telegraph Co. also has cooperated in the investigation, and tests have been made in its manholes from May 1, 1933, to October 15, 1937. Yearly reports. 6/ on the results obtained since the beginning of the survey have been published.The methods and procedure of conducting the survey in 1937 were the same as heretofore."

Jan 1, 1939

By G. R. Hopkins

According to the annual refinery-capacity survey of the Bureau of Mines, the number of refineries in the United States showed little change in 1940, increasing from 057 the first of the year to 562 at the close. Although a number of plants were dismantled in Texas and other States, more than compensating gains were made in California, Illinois, and other States. Low gasoline prices, competition for crude-oil supplies, particularly in Illinois, and the termination of a favorable distributing arrangement for independent plants in the Los Angeles area, forced about 50 refineries to close down in 1940. The number of operating plants accordingly declined from 461 on January 1, 1940 to 420 on January 1, 1941 and the number of idle plants increased from 86 to 136 in the same period. These developments were also reflected in the capacity data, the operating capacity declining from 4,196,694 barrels daily on January 1, 1940 to 4,180,588 daily on January I, 1941 and the idle capacity rising from 431,952 barrels to 53g8381 barrels in the same period. However, the completed capacity on January 1, 1941 (4,718,969 barrels daily) was 2 percent above the previous year.

Jan 1, 1941

By C. W., Davie

"DEFINITIONDiatomaceous earth consists almost entirely of the silicious remains of minute flowerless aquatic plants known as diatoms. The name diatomaceous earth, therefore, is to be preferred to others such as trade names, inappropriate terms, or names correctly applied to some other product. The following names should, therefore, not be used for diatomaceous earth,-- kieselguhr, infusorial earth, diatomite, celite, moler, bergnehl, English rottenstone, tripoli, tripolite, fossil earth, desmid earth, white peat, tellurine, randanite, ceyssatite, or any trade name.FORMATIONDiatoms live in practically all kinds of water, fresh or salt, hot or cold, still or running and under different conditions of depth and pressure. These minute plants assimilate inorganic salts from their environment and produce skeletons of silica much as mollusks secrete lime and form their Shalls. When the diatoms die they settle to the bottom together with anything else which may be present, such as sand, clay or volcanic ash. The organic matter gradually disappears leaving the silicious skeletons of the diatoms which, with impurities, make up the deposits of diatomaceous earth. These deposits which are still being foamed at the present time and which were produced throughout very different epochs, were more prolifically formed in the Tertiary, so that the thickest beds so far discovered are of that Age."

Nov 1, 1925

By C. J. Wilhelm

The disposal of brines produced with crude petroleum and natural gas has been a long-continuing problem to oil and gas operators as well as to farmers and stock-raisers in the vicinity of producing fields. An impartial appraisal of conditions pertaining to the problem of brine disposal leads to the conclusion that study of the technical consideration, with proper weight given to the economic and social factors, is the most desirable approach to this problem. Brine disposal is a problem of such magnitude in certain areas in the State of Kansas that in August 1934 a cooperative agreement was made between the Kansas State Board of Health and the U. S. Bureau of Mines for a cooperative technical study of methods of brine disposal.

Jan 1, 1935

By Clayton A. Landsidle

There has been little change in timbering methods in anthracite mines for 75 years, and technical information on strata control is almost wholly lacking. In order to assist the industry to establish technical data, the Bureau of Mines and a Northern field operator are cooperating in underground experiments, the first phase of which has been to investigate pneumatic packing. The four principal methods of packing in mining are hydraulic, pneumatic, mechanical, and hand. The hydraulic pa caring system is believed to have originated at Shenanodah, Pa., in 1864,4/ to prevent destruction of a church by surface subsidence after underground coal mining. This method was used again in 1884 to arrest an underground fire at Buck Ridge colliery, near Shamokin, Pa. In 1901 hydraulic packing was introduced to Europe in Upper Silesia, where it gained in popularity owing to the availability of large quantities of sand suitable for flushing .5/ Hydraulic packing has a number of disadvantages. Chief among these are the softening effect of large quantities of water on the mine floor conducive to heaving action; drainage and punning costs; and the inability to fill roof cavities completely in flat beds.

Jan 1, 1953

By Richard A. Walker

This report describes the development and performance of a multi-level, multi-function Calibration Light Source designed for field-calibration of a group of specific photometers. The Calibration Source is capable of providing ±35% accuracy calibrations at all of the following levels: 0. 05 foot-Lamberts, 6 foot-Lamberts, 6 foot-candles and 20 foot-candles. The Source was found to provide constant light output to within 1% over 50 hours of lamp operation and for line voltage variations of ±25%. It is compact and light-weight (11 pounds), and can be easily transported and used by one man in normal office environments (without requiring a darkroom).

Jan 1, 1976

By J. D. Dixon

This Bureau of Mines report describes the results of an investigation for developing and applying procedures for stabilizing excavations openings in highly yielding ground. The approach developed in this report involves nonlinear modeling of the progressive relaxation of the zones of rock mass around the excavations opening where Coulomb criterion of failure is exceeded. Stresses are calculated by using a computer code; Coulomb-failure condition is examined for both intact rock and joints (using strength parameters [~] and c). The rock mass in the failed zones is relaxed by reducing the Young's modulus of the rock based on an empirical formulation that is a function of the shape of the opening and the extent of the failed zone. In addition, the material in the failed zone is assigned reduced strength paramters 0' and c'. The limiting (or convergent) relaxed zone is obtained through an iterative process by manually changing the rock modulus and the strength parameters between iterations. Support pressures are computed by applying forces normal to the excavation surface. The approach is applied to the analysis of stability and support requirements for an entry in a longwall coal mine.

Jan 1, 1985

By Michael J. Pazuchanics

This report documents the current status of the U.S. Bureau of Mines ongoing investigation of the use of adaptive signal discrimination (ASD) systems to distinguish between cutting coal and cutting rock. Cutting-tool forces and vibrations were measured in the laboratory using both conical bits and roller cutters in a linear-cutting apparatus for several material samples and two cutting directions. A number of ASD systems consisting of one or more signal classifiers were trained and tested to study how data window size, type of signal feature, and combining (polling) of classifier results influence system performance. The results show that ASD system recognition rates can be improved by increasing data window size, removing air-cutting portions from the signal data, overlapping data windows, and combining (fusing) information at various levels of ASD system operation.

Jan 1, 2010

By A. E. Back

[Several processes for recovering manganese from low-grade ores have been proposed3/4/5/ in which an aqueous slurry of the ore is leached with gas containing nitrogen, oxygen, and sulfur dioxide as obtained from burning sulfur or roasting sulfide ores. The manganese dioxide is dissolved, and most of the sulfur dioxide is oxidized to sulfate, but an appreciable quantity of dithionate is usually formed, together with acid from oxidation of the sulfur dioxide. The over-all reactions may be represented as follows: (1) Mn02 + S02 = Mn++ + S04--. (2) Mn02 + 2S02 = Mn++ +S206--. (3) H20 + So2 + 1/2 02 = 2H+ 5S4--. (4) H20 + 2S02 + 1/2 02 = 2H+ + S206---.]

Jan 1, 1952

By C. J. Wilhelm

The disposal of brines produced with crude petroleum and natural gas has been a long-continuing problem to oil and gas operators as well as to farmers and stock-raisers in the vicinity of producing fields. .An impartial appraisal of conditions pertaining to the problem of brine disposal lead to the conclusion that study of the technical considerations, with proper weight given to the economic and social factors, is the most desirable approach to this problem . Brine disposal is a problem of such magnitude 1n certain areas in the State of Kansas that in August 1934 a cooperative agreement w s made between the Kansas State Board of Health and the U. S. Bureau of Mines for a cooperative technical study of methods of brine disposal.

Jan 1, 1935

By F. B. Petermann

The Bureau of Mines conducted electric furnace smelting tests on sintered flotation concentrate and siliceous log-washed are. The flotation concentrate was derived from the Maggie Canyon deposit of the Artillery Mountains area, Mohave County, Ariz., and contained, before sintering, 35.6 percent Mil and 19.4 percent Si02 + A1203. The log-washed ore was from the McGregor deposit of the Artillery Mountains area, Mohave County, Ariz., and contained 31.2 to 33.6 percent Mil, 19.5 to 27.6 percent Si02 + A1203, and 2.5 percent Pb. This work was undertaken to determine the most effective smelting technique for producing standard products from such nonspecification ore and concentrates. The objective was to collect data, using a small furnace, which would be reasonably accurate and permit extrapolation to large-scale practice for comparing with results on specification-grade are.

Jan 1, 1962

By S. C. Termes, P. E. Richardson, R. L. Wilfong

"The Bureau of Mines conducted research on the flocculation of various minerals with insoluble cross-linked starch xanthate (ISX) to determine its potential as a beneficiation technique for low-grade, highly disseminated ores and for selective desliming. Covellite, chalcocite, pyrite, pyrrhotite, chalcopyrite, bornite, sphalerite, galena, and molybdenite fines flocculate with ISX. Floc formation, floc size, and settling rate are dependent on pH, with the pH dependence differing for each mineral. Quartz is not flocculated by ISX. Experiments to obtain selective flocculation of sulfides from quartz were attempted. Good selectivity was only obtained for the bornite-quartz system. Post flocculation separations resulted in flocculated bornite in grades as high as 92 pct. Evidence is presented that the flocculation of many of the sulfide minerals with ISX may involve covalent bonding of the xanthate group to lattice metal site(s). INTRODUCTIONBecause of the increasing interest in selective flocculation as a beneficiation technique for low-grade, highly disseminated ores and for selective desliming, the Bureau of Mines has been investigating the flocculation behavior of several cross-linked starch derivatives containing chelating groups. This report dis cusses the flocculation of sulfide mineral fines by insoluble cross-linked starch xanthate (ISX).Polymeric materials such as ISX, which contain a chelating group of known re¬activity towards specific mineral surfaces, were first proposed by Slater, Clark, and Kitchener (1), 3 Kitchener (2), and Attia and Kitchener (3) as selective flocculants for mineral fines with particle aggregation possible through a bridging mechanism. ISX appeared to be attractive as a sulfide mineral flocculant because (1) alkyl xanthates are known to react selectively with sulfide minerals"

Jan 1, 1983

By B. K. Shibler, A. O. Ipsen, W. W. Agey

"INTRODUCTION As a part of the program of investigation of domestic sources of manganese ore, mining engineers of the Bureau of Mines obtained and examined samples of ore from six properties in the vicinity of Pioche, Lincoln County, Nev., and from one property near Caliente, Lincoln County, Nev. As the ores were too low-grade to be acceptable for the direct production of ferromanganese, their amenability to concentration by ore-dressing methods was investigated.In general, the Pioche ores had a low manganese content and, owing to extremely intimate association of manganese minerals with iron oxide and nonmetallic gangue, were refractory to concentration by ore-dressing methods. Only two samples (Zero Gap and Wheeler ores) were amenable to the production of concentrates that would sinter to a marketable plus 35-percent manganese grade. The Prince Consolidated and Ely Valley No. 1.ores were roasted and sintered to produce lead-silver-zinc fumes. The residues were of possible value as manganiferous iron ore. No marketable manganese products were made from Calton semi-oxidized ore, but over 80 percent recoveries of lead, silver, and zinc were made by bulk sulfide flotation followed by Diming of the sulfide concentrate. No satisfactory results were obtained by treatment of Golden Eagle and Ely Valley No. 2 ores.The Cudverwell ore was amenable to the production of high-grade manganese concentrates by ore-drssing methods. However, fine grinding was required to effect mineral liberation, and loss of manganese as slime limited the mangenese recoveries obtainable.In the coarse of the investigations, many data were obtained and compiled, but for the sake of brevity, several data, of secondary importance have been omitted or condensed, and only the tests giving the more promising results are discussed in detail. For convenience, the report has been divided into two parts, one opertaining to the Pioche ores and the other summarzing results obtained by testing Culverwell ore."

Aug 1, 1947

By D. Harrington

The record of fatalities from mine explosions in the United States during the past 3 years has been the best in the history of the mining industry. During these 3 fiscal years, mine explosions have resulted in an average of 4I0 deaths per year, as compared with an average of 153 deaths per year for the preceding; 5 years; an average of 542 deaths per year for the 3-year period 1907-09, inclusive, just before the organization of the U. S. Bureau of Mines; and a yearly average of 265 deaths per year for the 20-year period prior to 1929. This remarkable reduction in deaths from mine explosions demonstrates clearly that mine explosions can be controlled; in fact, they can be prevented when or if the mining people of the United States see fit to take the readily available precautions necessary to bring about this desirable objective. Several large coal-producing States, which in the past have had numerous disastrous explosions, have been free from such disasters for continuous periods of as much as 6 years or even longer. The bituminous mines of Pennsylvania, the largest coal-producing State, give a good example of what can be done to prevent explosions; this State has had only one major explosion (and it resulted in 7 fatalities) during the past 6 years, and no explosion occurred in the several hundred bituminous-coal mines of the State during the past fiscal year. This is a truly remarkable record when compared with past performance in any year in the operation of coal mines in Pennsylvania.

Jan 1, 1936

By A. T. Iannacchione

The Bureau of Mines established geologic factors affecting the mining of the Lower Kittanning coalbed to aid in coalbed minability studies and examined the occurrence of "wants" (places where coal is missing) and types of unstable roof rock strata. Trends established from mapping, including prediction of areas of high methane emissions, were extrapolated to unmined areas. 'Wants' in the coalbed are of two types: Erosional and depositional. Erosional features occur where north-south-trending sand-filled channels cut into the coalbed. Variations in depositional environments have caused the coalbed to "split" into several thinner units. Slickensides, commonly indicative of unstable roof, are adjacent to and on the underside of sandstone channels; they were caused by differential compaction and by soft sediment sliding along the contact between the sandstone and adjacent shale. The frequency of unstable roof also increases where the interval between the Middle and Lower Kittanning coalbed is less than 30 feet. The zones of weakness at the contacts above and below the Middle Kittanning coalbed are the controlling factors for unstable roof in these strata. Methane emissions from the coalbed are controlled primarily by depth, fracture permeability, and rank of coal. Local geologic factors are coalbed thickness, associated rock strata, structure, and proximity to outcrop.

Jan 1, 1979

An active list of permissible explosives was published in December 1936 as part of Bureau of Mines Report of Investigations 3324, under the title "Active List of Permissible Explosives and Blasting Devices Approved Prior to July 31, 1,936." This list included 170 brand names. Changes in the list that have been authorized to June 30, 1937 placed 35 additional brands of permissible explosives on the active permissible list as a result of tests, changes in brand names, or transfer from the inactive list. Ten permissible explosives were transferred from the active to the inactive list. The present list contains 196 brand names, one explosive having been placed on the list subsequent to June 30, 1937. The brand names of the permissible explosives placed on the active list are as follows: [ ]

Jan 1, 1937

By E. P. Hayes

This report supplements the date contained in Bureau of Mines Information Circular 6156, "Special features of core drilling in the salt beds of Western Texas and New Mexico," by J. S. Wroth. That circular dealt with the drilling of the first 12 of the 24 potash tests made by the U. S. Bureau of Mines in cooperation with the U. S. Geological Survey; this report is concerned with the drilling of the last 12 tests. ACKNOWLEDGMENTS The writer is indebted to R. E. Heithecker, the Bureau of Mines engineer who had charge of the drilling of tests 13 to 17, for his well-prepared records on the drilling of these tests.

Jan 1, 1933

By R. L. Levens

The Underground Injection Control program was promulgated in 1981 by the U.S. Environmental Protection Agency under the provisions of the Safe Drinking Water Act. Placement of mine waste backfill underground is considered underground injection under the provisions of this program. A major issue is whether mine waste that is regulated as a contaminant source on the surface should be disposed of underground. The U.S. Bureau of Mines conducted research to investigate the impacts of mine waste sandfill on the quality of ground water. Analyses of water samples collected before and after contact with sandfill in a 10-year-old stope, as well as samples of the sandfill itself, were used to ascertain the influence of the sandfill after mine closure and subsequent flooding. Computer models supported the hypothesis that oxidation of pyrite by oxygen, accompanied by dissolution of carbonates, was the predominant reaction controlling the quality of the water being discharged from the stope. Concentrations of metals released as a result of acid production remained near or below detection limits. Metals release after mine flooding is expected to remain low as a result of the buffering by the sandfill and the reduced rate of oxidation.

Jan 1, 2010

By E. P. Barret

Differences in the reducibility of iron oxide materials have been recognized for a long time. Limonites are deoxidized more readily than hematites, and unaltered magnetites are the most difficult to deoxidize. Sinters are found between hematites and magnetites and vary considerably in reducibility, depending on the sintering practice followed and on the degree of fusion of the product. The increased activity in the beneficiation of taconite recently has made available a new blast-furnace raw material, namely, iron oxide pellets made from magnetic taconite concentrate. Many of the data in this paper apply to these pellets, or glomerules, as they were called when this method of agglomerating iron ores was first considered. To clarify the terms applied to iron oxide materials in this paper, the following definitions are given. Agglomeration is the general term applied to all methods of compacting or consolidating fine iron oxide materials. Sinter is the product from a Dwight-Lloyd or Greenawalt sintering machine. Pellets are formed by balling fine, moist oxide in a rotating drum at room temperature, followed by heating in a shaft furnace to a temperature below that of incipient fusion to develop a permanent bond. Nodules are formed by heating the iron oxide material to incipient fusion in a rotary kiln. Briquets are formed in a mold under pressure, with or without the addition of a binder, and burned to develop a permanent bond.

Jan 1, 1949

By H. M. Urban

This paper, one of a series being prepared for and published by the United States Bureau of Mines on methods and costs of mining at various mica mines in the United States, describes the methods now in use in the principal mica mines of the Southern Appalachian States. Those 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 some instances cause embarrassment to individual producers as well as to the industry as a whole. On the other hand, operating costs are essential to the technical discussion and study of 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, 1932