Search Documents

By Lex B. Golden

The purpose of this investigation was to evaluate the corrosion properties of certain alloys of titanium and to compare them with those of unalloyed titanium. Such information should make it possible to determine the desirability of substituting these alloys for commercially pure titanium in certain applications. Titanium-manganese, titanium-chromium-iron, and titanium-vanadium-iron alloys, with 2 types of unalloyed titanium, I consolidated by arc melting and the other by powder-metallurgy techniques, were included in the study. Tests were carried out in sulfuric, hydrochloric, phosphoric, nitric, and mixed acids and in chloride solutions. All solutions were saturated with air.

Jan 1, 1957

By E. C. Lane

The motor gasoline that is being marketed in the United States this winter is in general, more volatile than that sold a year ago. This increase in volatility is shown by a lowering of the distillation temperatures, ranging from 2°F. at the average initial boiling point to 5°F. at the average end point. During the past eight and. one half years the Bureau of Mines has made semi-annual surveys of the gasoline marketed in the United States, the survey Just completed being the seventeenth in the series. The cities in which samples have been collected, have been chosen as representative of the more important marketing territories, as it is obviously impracticable to obtain a sample of every gasoline sold in the entire country. Samples were collected in Boston for the first time since 1919. It was believed advisable to include samples from that district in order to give a better balance to the survey for the country as a whole.

Jan 1, 1928

Objective To characterize the roof fall risk associated with underground limestone mining. Background During the first 5 years of this decade, more than one-fourth of the underground mining fatalities occurred as the result of fall of ground. The large openings in underground stone mines present limitations in observing ground conditions because of floor-to-roof heights ranging from 20 to 60 ft or more. Generally, the status of ground conditions in under-ground stone mines is based on observation and experience obtained during mining development. Some mines use monitoring instruments to gain information on roof conditions, but this practice is typically focused and localized to address issues in a particular area or section of the mine. The Roof Fall Risk Index (RFRI) described here provides a method of systematically characterizing the risk of roof falls to enhance the safety of mine workers. Approach As in many industries, a defective product signals the potential for failure. Similarly, defective rock or strata in an underground stone mine presents a potential risk. Assessing ground conditions relative to the concentration of defects observed provides a way to index or rate these conditions and the subsequent risk. Through observations at approximately 50 underground limestone mines in the United States, strata defects were categorized to develop a quantitative method for determining the RFRI. This method is specifically geared to underground lime-stone mines because strata defects are difficult to see and limited by the experience and knowledge of the observer. Overall, 10 defect categories were deter-mined: 3 that relate to geology, 4 that result from mine development, 2 that are indicative of the roof profile, and 1 that addresses moisture or water flow (see RFRI Chart 1). The defect categories are also weighted to reflect the conditions indicative of roof or strata movement or separation (categories 4 through 8). These weights are multiplied by the assessment value to determine the total category value. The benefit of using monitoring techniques to gain information on roof conditions is also factored into the RFRI for overall assessment of an area in the mine. Each defect category is assessed with a value of 1 to 5 based on parameters as defined in each defect category, with 5 indicating the highest degree or level of defect. The assessment value of 3 is also used when information on a parameter is unknown. The parameters for the defect categories are illustrated in RFRI Chart 2 for use in determining the assessed value. How It Works The RFRI provides a means to categorize the risk for roof falls in underground stone mines. The concept of this calculation is aimed at providing an indication of the level or degree of defect relative to the area of the mine examined. The RFRI for the calculation produces a distribution where RFRI values approaching 0 represent a stable condition and those ap-proaching 100 represent an unstable condition.

Oct 1, 2006

To develop a quick, safe, and effective method that allows workers at mineral processing operations to clean their dust-soiled clothing periodically throughout the workday. Background Reducing workers' respirable dust exposure to silica and other harmful dusts and contaminants is an ongoing goal in the U.S. mining industry. One area of known worker exposure is from contaminated work clothes. A U.S. Bureau of Mines report documented a number of cases where a tenfold increase in a worker's dust exposure was measured from contaminated work clothes. In these cases, the dust emitted from clothing caused the worker's dust exposure to exceed the permissible exposure limit in less than 2 hours. The most effective way to eliminate this dust source is to have workers clean or change their work clothes. There are two federal regulations that impact the clothes-cleaning process. The first states that at no time shall compressed air be directed toward a person, but that when compressed air is used, then all necessary precautions shall be taken to protect persons from injury. The second regulation states that compressed air should only be used for cleaning purposes when it is less than 30 psi and used along with personal protective equipment. For the mining industry, by default, the only approved method to perform clothes cleaning is to have workers vacuum their clothes using a HEPA filter system. This is very difficult and time-consuming and, in most instances, not very effective. Most workers would prefer to use a single compressed air hose to blow dust from their work clothes. However, not only is this method prohibited by law, it usually creates a significant dust cloud in the work environment and contaminates coworkers.

May 1, 2005

To help mine safety and health professionals manage and reduce hazardous noise exposure with a software tool that simplifies the record-keeping and analysis process. Background Hearing loss resulting from overexposure to noise continues to be a problem throughout the U.S. mining industry. Studies indicate that 70%?90% of all miners have a noise-induced hearing loss severe enough to be classified as a hearing disability by the time they reach retirement age. To address this problem, the National Institute for Occupational Safety and Health (NIOSH) developed the Determination of Sound Exposures (DOSES) software program. DOSES is designed specifically for use by mine management and safety personnel to simplify the record-keeping and analysis associated with time-motion studies, making it easier to identify and solve noise exposure problems.

Jul 1, 2009

Objective To accurately measure very low air velocities (0-100 ft/min) in U.S. large-opening underground metal/nonmetal mines. Background Hundreds of metal/nonmetal underground mines operate throughout the United States. They extract commercial products from deposits such as limestone, salt, and gypsum. Mining generates a wide variety of gases and dusts, such as silica, diesel exhaust, radon, blasting byproducts, and perhaps even methane. If these substances become airborne, they can adversely affect the health and safety of underground workers. Many metal/nonmetal mines have large cross-sectional airways that could be 60 times larger than an average underground coal mine entry. These large airways require adequate volumes of fresh air to dilute, make harmless, and exhaust the toxic and, at times, explosive byproducts. However, in some underground mine sections, air movement is barely perceptible. The technology of measuring very low air velocities will become increasingly more important for operators of large-opening stone mines in order to monitor miner exposure to diesel particulate matter. Conventional anemometers (e.g., vane) are capable of accurately measuring air velocities only above 100 ft/min. Thus, it was necessary to investigate other anemometry technology to detect low air velocities in the range of 0-100 ft/min. Two different portable ultrasonic anemometers were tested. Actual testing was done in an underground limestone mine with openings about 51 ft wide by 29 ft high. Ultrasonic Anemometers Vane-type anemometers are commonly used by engineering personnel throughout the underground coal mine industry. They work well in measuring air velocities >100 ft/min. However, a separate technology, e.g., portable ultrasonics, is needed to measure air velocities much below 100 ft/min at various places within the large mine opening. Laser-doppler technology was also considered for this application, but was ruled out because of its high cost and other technical limitations. With no moving parts, the portable ultrasonic anemometers are claimed to be accurate down to about 1or 2 ft/min. The first type of ultrasonic anemometer that was examined underground is manufactured by Gill Instruments Ltd., Hampshire, U.K. The U.S. distributor is IN USA, Needham, MA. The Gill Instruments Solent Volometer (figure 1) is a battery-powered, single-axis anemometer meant for measuring low to medium air flows up to1,999 ft/min. It uses the ultrasonic "time of flight" principle where pulses of high-frequency sound are transmitted along the air flow path and the time taken to reach the receiver is measured. The faster the air speed, the quicker the pulses reach the receiver. The second ultrasonic anemometer that was examined under-ground is manufactured by Airflow Developments Ltd., Buckinghamshire, U.K. The U.S. distributor is Airflow Technical Products, Inc., Andover, NJ. The Anemosonic UA-6 (figure 2) is a battery-powered, handheld instrument with digital display. It measures air velocity (0 to 9,999 ft/min) or volume flow, flow turbulence intensity, and air temperature. Neither device is considered to be intrinsically safe for use in underground gassy coal mines. A comparison of salient specifications of both instruments is shown in table 1. The total suspended weight includes the instrument (Gill) or instrument probe (Airflow) plus about 35 ft of connecting cable attached to the pole. This combination of instrument plus cable length allows two operators to measure air velocities up to about 30 ft above the mine floor. Figures 1 and 2 show how each unit would be attached to an extensible, graduated fiberglass rod in order to position the sensor probe at a certain spatial point (centroid of the quadrate) within the underground large opening.

Jan 1, 2003

By C. L. Severy

The Reeder No. 1 well was drilled by the Bureau of Mines in cooperation with the Geological Survey as agents for the Defense Plant Corporation. The well is south of Crescent Junction near Thompson, Grand County, Utah. It was started May 5, 1942, and completed August 3, 1942, for the purpose of con-firming the presence of magnesium salts in a deeply buried bed. Drilling was done under contract by the Mack Drilling Co. This report contains an outline of the physical features of the well, a brief history of drilling, and a description of the deposits and occurrences of oil and gas encountered in the drill hole. The work performed by the Bureau of Mines is described in considerable detail, with particular emphasis on drilling procedure and sampling. The report is concluded with a brief description of core-sample preparation for analyses. Appendix A comprises a log of the drill hole, and appendix B is a tabulation of analyses of cores.

Jan 1, 1949

By M. B. Bransford

A calculation procedure was evolved by the Bureau of Mines for determining the heat-transfer characteristics of dilute gas-solid mixtures in an externally heated tube. The procedure accounts for differences in gas and particle velocities and covers a range of particle sizes. Heat transfer coefficients obtained by the calculation procedure are compared with values reported in the literature.

Jan 1, 1970

By L. B. Pankratz, R. Barany, W. W. Weller

Experimental determinations were made of the heats of formation at 298.15 ° K of cuprous ferrite and cupric ferrite ; the heat capacity of cuprous ferrite was measured over the temperature range from 50 ° to 298 ° K and the entropy at 298.15 ° K was evaluated ; the heat contents of cuprous ferrite and cupric ferrite above 298.15 ° K were measured to 1,500 ° K and 1,100 ° K , respectively . These thermodynamic values were combined with other pertinent data to obtain heat and free energy of formation values at high temperatures . The stability of the two ferrites with respect to their constituent oxides is discussed . Thermodynamic values are included for the decomposition of cupric ferrite to form cuprous ferrite , magnetite , and oxygen .

Jan 1, 1964

By E. Chin

The production of crude mineral commodities in Bangladesh was limited to natural gas, a small amount of construction materials, and clay for ceramics and bricks. No metallic minerals were mined. The only mineral commodity of economic significance was natural gas. Natural gas production has 'been climbing steadily and becoming an increasingly important source of energy for the country. Proved gas reserves were over 4.5 trillion cubic feet, but the amount has been increasing as exploration discovers large new deposits. Some sources quote reserves at over 10 trillion cubic feet.

Jan 1, 1984

By Henry E. Blake

The Bureau of Mines has been engaged in a continuing research effort to develop processes for increasing the recovery and utilization of fluorine from low-grade resources. This current research has shown that over 98 percent of the fluorine in phosphate rock is extracted when the ore is treated with excess phosphoric acid in the presence of water vapor at 150° to 180° C. More than 80 percent of the fluorine can be recovered as fluosilicic acid, which can then be converted to commercially useful hydrogen fluoride or fluorspar by previously developed Bureau processes. Extraction of P205 from the ore was about 98 percent in batch tests and 90 percent in semicyclic tests.

Jan 1, 1974

To reduce equipment operator exposure to respirable dust in enclosed cabs by examining the effectiveness of retrofitting air pressurization and filtration systems on existing cabs.

Jan 1, 2001

By J. P. Capp

The Federal Bureau of Mines and the Alabama Power Company conducted an experiment in underground gasification of coal at Gorgas, Ala. involving the use of hydraulic fracturing to increase the air acceptance of a coalbed for the introduction of combustion air and removal of product gases. Air acceptance is defined as the flow rate of air which can be injected into the coalbed at 65 p.s.i.g. This was the second time the hydraulic-fracturing technique was used at Gorgas. Sand suspended in a heavy oil served as the fracturing fluid in the first experiment; in the second the sand was two to six times larger and was suspended in a water-starch gel. In addition to providing further tests of the underground-gasification process, the purpose of the second experiment was to determine the effects of the larger sand and greater volumes of a water-base fluid on (1) the extent of the fractured area, (2) the air acceptance of the coal, and (3) the rate at which a gasification path could be carbonized (linked) through the coal, and to compare these results with those of the first experiment. The coal was fractured by injecting 11,000 lb. of sand and 33,580 gal. of water and water-gel at 200 to 600 g.p.m. and 900 to 1,000 p.s.i. The fluid fractured the coal and the sand served as a propping agent to hold the cracks and crevices open. Pressures during the fracturing operation at test boreholes indicated that the fracturing fluid extended only about 150 ft. from borehole H, the point of application of the fracture. Injection of air revealed that the air acceptance of the coalbed within this e t was materially increased. On the other hand, increased air acceptance also was noted at boreholes up to 280 ft. from borehole H and at the electrolinking area 300 to 400 ft. away, indicating that the fracture effects extended considerably farther than was evident from observation. Similar effects were noted at approximately the same distances after the first hydraulic fracture.

Jan 1, 1961

By E. C. Lane

The motor gasoline that is being marketed in the United States this summer is slightly more volatile than that sold a year ago. The increase in volatility is shown by a lowering of the distillation temperatures, ranging from 2°F. at the average initial boiling point to 4°F. at the average end point. During the past nine years the Bureau of Mines has made semiannual surveys of the gasoline marketed in the United States, the survey just completed being the eighteenth in the series. The cities in which samples were collected have been chosen as representative of the more important marketing territories, as it is obviously impracticable to obtain a sample of every gasoline sold in the entire country. Samples were collected in Omaha as well as in the 11 cities where samples were taken last winter. It was believed advisable to include samples from Omaha in order to give a better balance to the survey for the country as a whole.

Jan 1, 1928

By Nicholas Kyriazi, John P. Shubilla

A joint effort by the U.S. Bureau of Mines (USBM) and the US. Mine Safety and Health Administration (MSHA) was undertaken to determine how well self-contained self-rescuers (SCSR's), deployed in accordance with Federal regulations (30 CFR 75.1714), held up in the underground environment with regard to both physical damage and aging. This report presents findings regarding laboratory-tested SCSR's in the fourth phase of testing from 1989 to 1993. The SCSRYs were tested on human subjects and on a breathing and metabolic simulator (BMS). These results indicate that most of the apparatus, if they pass their inspection criteria, perform as expected except units with manufacturing defects. However, when the apparatus are carried in and out of the mine daily and stored at the working section, they may suffer abuse. Physical signs of abuse, unless extremely obvious, are frequently not detected by the miners or mine operators. In addition, some apparatus collected for this study had not been returned to the manufacturer in a recall effort for correction of a manufacturing defect. In both cases, the apparatus would have presented problems in emergency use. Recommendations include improved training in inspection procedures and better enforcement of recall notices.

Jan 1, 1994

By Jerome J. Hoeppner, Walter W. Fowkes

The Federal Bureau of Mines has determined the distribution of forms of sulfur for several lignites and gasification chars and noted the changes induced by the gasification process . A method was adopted for quantitatively determining sulfide sulfur that was found to be present in the chars , although absent in the lignites . Changes in the behavior and distribution of sulfur forms were further investigated concerning the ashing of lignites and chars under standard conditions , as well as at various temperatures , and the determination of volatile matter applied to both chars and lignites . The authors concluded that the first and greatest change in the form of sulfur present in natural lignite , upon heat treatment , resulted from the reduction of pyritic and sulfate sulfur to sulfide . Organically - bound sulfur originally present is less reactive , but largely disappears on strong ignition . An appreciable part of the sulfur content of natural lignite is fixed in the char as sulfide and in the ash as water - soluble sulfate and will affect the summation of constituents , to a greater or lesser degree , in reporting the ultimate analysis of a lignite or char .

Jul 1, 1960

By Synthia N. McIntosh

The U.S. Bureau of Mines investigated the feasibility of using ammonium carbamate (NH2CO2NH4) leaching to recover manganese from steel plant slag. This investigation showed that treatment of the slag in hydrogen prior to leaching enhanced manganese extraction. Up to 80 pct of the manganese and 50 pct of the iron could be extracted from a silicon steel slag that had been pretreated in hydrogen at 700° C. Two 4-h leaching stages conducted at ambient temperature with a solution containing ammonia and carbon dioxide dissolved manganese and iron as their carbamate complexes. Heating the pregnant solution to 65° to 85° C decomposed the complexes and precipitated the metals as insoluble carbonate salts. Ammonium carbamate leaching of other slags from several steelmaking plants produced lower manganese extractions, which suggests that the method cannot be applied satisfactorily to all steelmaking slags

Jan 1, 2010

By P. M. Sullivan

At its College Park Metallurgy Research Center in Maryland, the Bureau of Mines has installed and is operating a 5-ton-per-hour pilot plant for continuous mechanical separation of values contained in raw urban refuse. The entire sys tern was assembled using commercially available equipment. The process relies on multistage processing including shredding, air classification, screening, gravity concentration, and electrostatic separation. Compactor trucks deliver raw refuse collected along typical routes in metropolitan Washington, D.C., to the pilot plant. The loads are separated into concentrates of (1) light-gage iron, (2) massive metals, (3) glass, (4) putrescibles and waste combustibles, (5) paper, and (6) plastics. While some refinements remain to be made in the processing system flow-sheet, the data obtained to date have been highly encouraging, indicating favorable economics for commercial-size plants.

Jan 1, 1973

By F. Fraas, H. H. Storch

"In the second paper 4 of this series, data were presented concerning the decomposi¬tion of polyhalite by saturated salt solutions. It was found that uncalcined polyhalite upon leaching with boiling saturated sodium chloride solutions yielded a brine in which the (K2 Mg) /304 ratio was considerably higher than that obtained from the calcined material, and for this reason appeared more suitable for the production of potassium chloride. It was found, in fact, that the leach liquors from uncalcined polyhalite deposited a mixture of KC1 and NaC1 upon evaporation and subsequent cooling, whereas those from calcined polyhalite yielded mixtures which contained not only potassium and sodium chlorides but also large quantities of glaserite, K3Na (S04)2. Hence it was decided to study the evaporation of the uncalcined poly—halite leach liquor and postpone experiments on the calcined polyhalite liquors until such time as a process for further removal of sulphate was developed.A considerable body of equilibrium data is available in the literature on thesystem K+ Mg++ — Na+ Cl—S04 =,— H20 for temperatures up to 83º C. Owing, however, tothe lack of data other than that corresponding to the invariant points and the complete absence of data for temperatures of 100 to 115°C., and owing to the fact that supersaturation phenomena render unsafe the prediction of the behavior of such a system upon evaporation, it was considered essential to obtain the necessary data by actual evaporation and analysis of the brines thus obtained."

Feb 1, 1931

By A. C. Johnson, McHenry Mosier

The Bureau of Mines has adapted its activities to needs of national defense and to conditions brought about by the war program . Its work is now oriented solely to war problems . After studying about 1,600 deposits of war minerals , exploration projects have been undertaken on 96 of the most promising , of which 56 have proved successful . These have indicated that 56 million tons of ore of commercial or near -commercial grade can be utilized to meet war requirements . Included in this amount are 1 million tons of tungsten ore ; 4 million tons of chromite ore, 10 million tons of manganese ore , 2 million tons of antimony ore , 1 million tons of mercury cre , and 28 million tons of iron ore . Work done in connection with exploration projects included 172,000 feet of surface trenching , 210,000 feet of drilling , and 21,000 feet of shaft sinking . Nearly 100,000 samples were taken, on which 500,000 analyses were made . Extensive metallurgical tests were made on ore from many of these deposits , both in the laboratory and in pilot plants , in connection with research to develop metallurgical processes for their treatment .

Jan 1, 1943