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By Hiram C. Draper

The Mining Division of the Bureau of Mines, in cooperation with the Obstacle and Demolition Branch, Engineer Research and Development Laboratories, Department of the Army, undertook some extensive tests to determine the effectiveness and limitations of using standard demolition-type shaped charges in underground Mining. The tests proved the shaped charge has no practical application in the functions of mining covered by this report. At an approximate cost of 0 per foot hole plus spall produced by the most efficient single shots with the M3 shaped charge, the cost is over 20 times that of producing a better hole with a rock drill. The concussion would prohibit its use in many mines, and the excess carbon monoxide gas liberated by the pontolite explosive would be an additional hazard when used underground.

Jan 1, 1948

By M. Hertzberg

This Bureau of Mines report describes experimental and theoretical studies of diffusion flames in free convection. The cross-coupling between buoyancy-induced flows and the combustion process is explored as it relates to the size, structure, and radiative balance of flames. New data are presented for the size-dependent radiance oscillations of diffusion flames and for the angular distribution of the total radiant intensity from a small methanol pool flame. Both amplitude and frequency of the measured oscillations are compared with theoretical predictions that are based on a new view of the structure of diffusion flames. This new view, which is at variance with the traditional one, assumes uniform reaction in the diffusive mixing zone, and recognizes the significance of the role played by convective buoyancy and its duality in both aiding and impeding flame propagation. Buoyancy quenches propagation at low burning velocities, introducing a real discontinuity in the combustion rate. A "flammable volume" is thus defined as that bound between lean- and rich-limit contours. However, in the flow disturbances generated by combustion waves that consume that volume, buoyancy aids propagation by promoting the convective mixing of a new flammable volume. The measured radiance oscillations are manifestations of these propagation and remixing cycles.

Jan 1, 1978

By N. S. Dalal, X. Shi, P. M. Gannett

"Chromates are known to induce tumors (1, 2), mutations (3), and DNA damage (4-6). However, the underlying biochemical mechanism(s) is (are) not fully understood (6). Recent studies have indicated that hydroxyl (·OH) radical may play an important role (7-11). The mechanistic studies of Cr(Vl)-related ·OH radical generation in biochemical systems have shown the reaction of a Cr(V) species with hydrogen peroxide (H20 2 } through a Fenton-like mechanism to be one of the important steps (9-11): Cr(V) + H20 2 - Cr(VI) + ·OH + OH-. (1)In biological systems the Cr(V) species are generated via the reduction of Cr(VI) by a variety of components, such as microsomes (12), mitochondria (13), mitochondrial electron transfer complexes (14), and at least three flavoenzymes (glutathione reductase (GSSG-R),3 lipoyl dehydrogenase, and ferredoxin-NADP+ oxidoreductase) (9, 15, 16). In the case of flavoenzymes, Cr(V) formation is accompanied by the reduction of molecular oxygen ( 0 2 ) to H20 2 • The Cr(V) species then reduces H20 2 to generate •OH radicals and Cr(VI) (16).To understarid the mechanism by which Cr(V}-generated ·OH radicals cause cytotoxicity, Aiyar et al. (8) investigated the reaction of Cr(VI) and H20 2 to generate ·OH radical and its reaction with 2'-deoxyguanine (dG) to form 8-hydroxy-2'-deoxyguanine (8-0HdG}:"

Mar 1, 1992

By Charles W. Huggins

Knoop hardness indentations were studied and measured with the electron microscope on TiB2, HfC, and A1B12 crystals. A detailed description of replicating the indentations using collodion and Faxfilm is made. A John Hopkins grating having 28,800 lines per inch was used to accurately determine the magnification used on the electron microscope. The primary objectives were to prepare carbon replicas of hardness indentations, to measure the indenations accurately, and to compare the results with those obtained with the light microscope. The resulting data showed excellent agreement between the measurements made on the replicas with the electron microscope and those made with the optical microscope. The replicas made from collodion showed slightly better agreement with the light optical values than did the replicas made from Faxfilm.

Jan 1, 1963

By R. J. Henry

This paper describing the mining practices at the Teck-Hughes mines at Kirkland Lake, Ontario, is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in various mining districts. HISTORY Prospecting was begun in the neighborhood of Kirkland Lake in 1906, but staking did not take place until 1911. Gold-bearing veins were discovered by surface trenching in 1913 on the mining claims which now make up the Teck-Hughes Gold Mines (Ltd.). A small mill was erected in 1916 after the completion of some underground exploration. A transmission' line was built in 1917 to the camp to provide adequate power for a vigorous underground campaign. Also in 1917 the present management took control operations since 1916 have been continuous,' with a steady increase in production to date.

Jan 1, 1930

By N. Greninger

The Bureau of Mines examined the possibility of a seasonal variation of respirable dust concentration in U.S. coal mines. The first step was to review company and MSHA-inspector dust samples that had been collected during the past several years in 14 selected mines for compliance purposes. Results indicated severe scatter in data; most standard deviations of the dust concentrations measured in winter and summer months were comparable in magnitude with the mean values of dust concentrations for the seasons. Therefore, a detailed statistical analysis was conducted. At the 90% confidence level, the company samples of three mines had winter means 0.15 to 0.54 mg/m3 higher than the summer means; six mines had negligible seasonal variations; and five mines had winter means that ranged from higher to lower than the summer means. Inspector data, however, were too sparse for analysis. In view of both the low frequency of occurrence of a seasonal effect and its wide scatter in several of the mines, the study was ended with the conclusion that seasonal varia-tion in respirable dust levels, in general, is an insignificant factor.

Jan 1, 1986

By S. W. Parr, T. E. Layng

There is presented below the results of experiments made on six samples of Utah coals furnished through the U. S. Bureau of Mines , under an agreement dated June 16th , 1920. The details of all values for all runs are tabulated and presented herewith . Clear The samples, consisting of approximately 150 pounds each, were received at the University of Illinois , on June 15 , 1920 , and are listed as follows : Creek , Wattis , Castle Gate , King , Standard , and Aberdeen . The proximate and ultimate, analyses of the various ccals from that region , representing all the types included in these samples , have already been made by the Bureau of Mines , and are available . * Similar determinations were also made on the particular samples forwarded for purposes of these experiments . The results obtained on the coal as received did . not very in any material feature from the values reported by the Bureau, they are shown in Table 1. It is of importance to note only that the oxygen content is uniformly high , namely approximately 9.5 to 11.5 per cent of the as- received coal , while the oxygen - hydrogen ratio is also high, being on the average approximately 2 ( oxygen) to 1 ( hydrogen) .

Sep 1, 1921

By E. H. Denny

Colorado coal-mine fatalities, which have gradually decreased since 1914, have shown a marked decline since 1924. Data on coal-mine fatalities in Colorado published by the U. S. Bureau of Mines5 indicate that the deaths per thousand 300-day workers have decreased from 9.13 in 114 to 6.14 in 1926, and that the deaths per million tons produced have decreased from 9.18 in 1914 to 4.98 in 1926. Table 1 gives fatality rates in Colorado and in the United States from 1914 to 1926 inclusive. [ ]

Jan 1, 1929

By D. E. Wolfson

The Bureau of Mines carbonized 35 coal samples from Logan and Mingo Counties) W. Va., at 900° C using the Bureau of Mines-American Gas Association method, and determined yields of products and physical properties of cokes. Twenty samples represented the No.5 Block, Stockton, Chilton, Cedar Grove, Lower Cedar Grove, Alma, No. 2 Gas, and Eagle beds in Logan County, and 15 samples represented the Coalburg, Buffalo Creek, Winifrede, Cedar Grove, Lower Cedar Grove, Alma, and No.2 Gas beds in Mingo County, W. Va, Chemical analyses were determined for all coals. All coals in both counties rank as high-volatile A bituminous. Most of the coals are chemically suitable for metallurgical coals. Coals with accept-able ash and sulfur contents can be used as major constituents in coking blends with higher rank coal to yield coke with satisfactory properties for blast furnace use.

Jan 1, 1967

By Wilbur I. Duvall

Twelve millisecond delayed blasts in four limestone quarries in Iowa were instrumented with arrays of vertical velocity gages to determine if the direction of propagation through the rock or the method of initiation of the blast had any effect upon the level of vibration. Two gage arrays approximately 90° apart were used to test the effect of direction of propagation. The vibrations from blasts initiated by three methods were recorded. Vibration records from these tests were analyzed for peak particle velocity as a function of distance from the blast. The data are shown to fit a power Law equation. Direction of propagation is shown to affect the value of the exponent n. The effect of charge size per delay interval on the level of vibration is removed from the data by scaling the travel distance by the square root of the charge weight per delay period. The method of initiating the blasts is shown to have a strong effect upon the level of vibration and the spread in the data from one shot to another.

Jan 1, 1963

By Edward Roberts

This is a progress report of an investigation by personnel of the Bureau of Mines from June to September 1951 to introduce preservative chemicals into growing timber. It also describes in detail the impregnation process, known as the collar method, developed by the United States Department of Agriculture2/ Twenty-eight trees were treated by this method, and a complete record was kept of each individual tree and of each timber cut from it. These timbers have been placed in a coal mine, and their tendency to decay is compared to that of adjacent untreated sets. Although several years will be required before final conclusions can be drawn, this report explains the appearance and encouraging results of the treated timber to date. Also included are some comparative costs of untreated timber, treated timber by the commercial pressure method, and treated timber by the collar method. INTRODUCTION In the hope of increasing the useful life of cut timber, experiments to impregnate growing trees with wood-preservative chemicals by utilizing the natural flow of sap have been carried on for centuries. None of the various methods used in these experiments has ever gained any widespread use because they have been commercially impractical.

Jan 1, 1953

By A. W. Deurbrouck

This Bureau of Mines report describes the preparation characteristics of the significant coalbeds from which samples could be obtained in Upshur County, W. Va. One of the 14 samples collected was of metallurgical quality as received, 6 could be sufficiently upgraded to provide acceptable products, and 7 could not be upgraded to metallurgical quality because of their high sulfur contents.

Jan 1, 1967

By ALICE V. Petar

Thallium is one of the rare metals that has come into commercial use within recent years . Its comparative scarcity , combined with a resemblance to the common metal lead , have retarded the development of uses for thallium . Although production is still measured in pounds rather than in tons , it is now finding application in a number of fields . Perhaps the earliest commercial use of thallium was as a constituent of optical glass of higher refractive power than similar glasses containing lead . One of the later applications to attract attention was the use of the oxysulphide in a sensitive electrical device similar to the selenium cell . The " Thalofide " cell , which was patented in 1919 , constituted for a time the most important outlet for thallium. During the next few years the limited use of thallium and its salts in other fields was insufficient to absorb an annual production of a few hundred pounds , and the price dropped from $ 16 or $18 per pound in 1922 to $ 5 per pound in 1924 . Beginning in 1925 several new uses were developed , especially as a poison for rodents and ants , and as a result the demand for thallium increased sufficiently to cause a recovery in price to the present level of from $12 to $15 per pound .

Jun 1, 1931

By Maria I. De Rosa

The U.S. Bureau of Mines conducted experiments for predicting materials' ease of combustion (smoldering onset, smoldering, flaming, and decomposition rates) by means of submicrometer smoke particle characteristics for the development of a simple test method. The experiments were carried out in an approximately 20-L furnace, with a 10-L/min airflow through the furnace for a 14-min duration, at set furnace temperatures of 150°, 250°, and 1,000° C. The variables studied as a function of time were the onset time of smoke particles, time and duration of maximum smoke particle generation, average concentration of smoke particles, and particles' average diameter, mass weight loss, and furnace temperatures. Results show that the onset time of smoke particles is predictive of materials' ease of smoldering, and the time of maximum smoke particle generation and its duration, coupled with mass weight loss, are predictive of materials' ease of smoldering and flaming (depending on the experimental temperatures), and decomposition rates.

Jan 1, 2010

By R. S. Olsen

The Bureau of Mines is engaged in research to recover aluminum from kaolinitic clay and other nonbauxitic domestic resources. As part of this work, calcined Georgia kaolin was prepared by a process that prevents slime formation and makes the leached residues fast settling and easy to filter. The leaching reaction for calcined kaolinitic clay in a 5 pct stoichiometric excess of boiling 23-to 26-pct HCI was found to be zero order. Rate constants based on the weight-fraction of aluminum in the clay were found to be between 0.095 and 0.15 min-1 depending on feed preparation and leaching parameters. The mathematical relationships between aluminum extraction and time for both batch and continuous, stirred-tank operations were derived and verified experimentally.

Jan 1, 1983

By S. H. Ash

In the early nineties it was observed by several European investigators and by C. S. Rice4 that an explosion could be checked and would not propagate in the parts of a mine where shale or other inert dust was present in large amounts.5 After the disastrous Courrieres explosion in France that killed 1,100 men, coal-dust explosion tests were made in France in 1907 and in Great Britain in 1908 which resulted in the conclusion that if enough incombustible dust were properly spread throughout passageways charged with coal-dust, the propagation of an explosion by the coal-dust could be prevented. In 1908 the Federal government authorized the investigation of the causes of mine explosions and of possible methods of preventing them, with the result that during 1911 the United States Bureau of Mines, after making several tests, suggested that rock-dust be used in gassy or dusty bituminous coal mines. Since that time, experiments and investigations6 have proved conclusively that widespread explosions can be prevented in coal mines by efficient rook-dusting.

Jan 1, 1930

By Franklin B. W. Woodbury

The Bureau of Mines, as part of its goal of helping maintain an adequate supply of minerals to meet national economic and strategic A needs, is evaluating alternative technologies to treat oxidized taconites. Since process control is an essential element in the application of these process technologies, research was performed on a prototype monitoring system utilizing a Californium-252 (252-Cf) neutron source and a thermal neutron capture-gamma ray spectra analysis method to measure the amount of iron and percent solids in process slurries. The prototype system was used to monitor the concentrate and tailing streams in a 900-lb/hr flotation pilot plant during continuous around-the-clock tests. The iron content of the process slurries was determined by measuring the total peak areas under the capture spectrum peaks at 7.626-7.632 MeV, the associated escape peaks at 7.136-7.122 and 6.626-6.612 MeV, and the iron doublets at 4.900 and 4.998 MeV. A potential method for determining the percent solids in process slurries using the 2.22 MeV hydrogen capture peak is discussed. Results of this work demonstrate a potential method for providing process control parameters using the data from thermal neutron capture-gamma ray reactions.

Jan 1, 1980

By M. D. Carver

The purpose of this investigation was to determine the effects of variations in content (near the residual level) of the impurities aluminum, nitrogen, manganese, and copper on the corrosion rate in pressurized hot water and in pressurized steam of zircaloy-3, a zirconium-base alloy of 0.25 percent tin and 0.25 percent iron. Thirty-five 10-pound ingots were cast with the appropriate additions of impurity elements, and these were converted to wrought sheets. These specimens were then tested both in water and in steam. The analysis of the resulting data showed that in environments of either pressurized hot water or superheated steam, corrosion rates increased with increasing content of aluminum, nitrogen, or manganese, but were not affected by variations of copper. The effects of aluminum and nitrogen were found to be greater than the effect of manganese. INTRODUCTION At the request of the Atomic Energy Commission (AEC) in August 1956, the Federal Bureau of Mines, in cooperation with Bettis Plant of Westinghouse Electric Corp., began investigating the effects of certain impurity elements on the corrosion rates of zircaloy-3 in pressurized hot water and in pressurized steam. It was necessary to know these effects in order to set control limits on residual impurity levels in zirnaloy-3, intended for heat transfer service in the nuclear reactor of the pressurized water type. A factorial expert it was designed by Westinghouse statisticians. The Atomic Energy Commission provided raw zirconium sponge purchased from Wah Chang Corp. The Bureau's laboratory at Albany, Oreg., made material of different combinations of impurity levels and subjected the material to corrosion tests. This report will describe the work done at the Bureau laboratory and will show, quantitatively the effects of different residual levels of aluminum or nitrogen, or manganese or copper on corrosion rates.

Jan 1, 1961

These proceedings consist of papers presented at Bureau of Mines Technology Transfer Seminars in December 1983 for the purpose of disseminating recent advances in mining technology in the area of mine ground control. The Bureau of Mines conducts several of these seminars each year in order to bring the latest results of Bureau research to the attention of the mining industry as quickly as possible.

Jan 1, 1984

By Sidney A. Suhler

A field operable, breadboard model, borehole radar was developed for the detection of hazardous geological anomalies in and above a coal seam in advance of mining. A four-inch diameter downhole probe was fabricated and tested in several environments. The radar transmitter was also employed in a cross-hole or through transmission mode to determine natural geotechnical and man-made conditions between boreholes. Sensitivity to underground conditions in both modes of operation were indicated.

Jan 1, 1978