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By B. W. Moore

The U.S. Bureau of Mines investigated the separation of heavy rare-earth elements (REE) in an ion-exchange process. An ion-exchange column consisting of two sections, a loading section and a separation section, provides high levels of REE loading and good REE separation with an expected processing cycle of less than a month, while current ion-exchange technology requires more than 5 months. A different resin is used in each section: sulfonic resin in the loading section and iminodiacetic resin in the separation section. The separation section is further divided into two segments: the first conditioned with NH4 and the second with acid. Erbium is loaded onto both segments of the separation column as a retaining ion. Bands of mixed REB eluting between separated bands of pure REB were recycled directly to the column. Without mixed-band recycle, over 80% of the REE eluted from the column was separated into fractions with 99% purity of each element; with such recycle, the percentage of separated elements can be increased to around 90%.

Jan 1, 2010

By R. T. Sorensen

Research and testing in a small scale equivalent of a commercial flota-tion plant was completed on four low-grade, iron-bearing materials from the western Mesabi range. Closed circuit-flotation of calcium-activated silica with fatty acid collector developed data for comparison with the batch process and highlighted problems not evident from previous bench testing. The four ore samples contained from 27 to 39 percent Fe and were equally represented by nonmagnetic taconite and semitaconite type materials. Iron concentrates containing 6.0 percent, or less, SiO2 were made 5, all four samples. Of the two material types, the semitaconite was the ore amenable to treatment, yielding iron recoveries of about 90 percent as cc pared with 70 to 80 percent for the other. Pilot plant tests showed that concentrate grade made in batch tests could be duplicated in the closed circuit and demonstrated that the amount of recoverable middling iron varied considerably between ore samples. The continuous tests also showed that water temperature strongly influenced results in the treatment of one ore but apparently was of indifferent consequence in another. Progress in thickening and filtration of flotation concentrates was made through introduction of tapioca flour to serve the dual role of iron mineral depressant and flocculant.

Jan 1, 1966

By M. Hertzberg

Results of a comprehensive study of the absolute spectral radiance of the infrared emissions from methane-air explosions are reported. The spectral growth of these expanding flames were recorded with a time resolution of 1 msec in the spectral range of 1.7 to 5.0 µm. Time-resolved spectra were obtained for methane-air mixtures as a function of stoichiometry, nitrogen dilution, and Halon dilution, in a 9-liter vessel under different venting conditions. Data are also presented for coal dust-air explosions. Temperatures, obtained from the absolute radiances and from a band ratio technique for methane-air, are internally consistent and are generally 50° to 200°K below adiabatic flame temperatures. All near limit mixtures gave essentially the same flame temperatures (1,500° to 1,600° K) regardless of whether the limit was obtained by dilution with excess air, excess methane, excess nitrogen, or Halon. The coal dust explosion spectrum is essentially a blackbody continuum at 1,500° K with some selective emission at 4.4 µm from hotter CO2. The data are analyzed in terms of the radiative dynamics of a sperically expanding flame zone. The importance of radiative transport is assessed. An equation is derived which relates the instantaneous fraction of combustion power radiated to adiabatic variables.

Jan 1, 1973

The National Institute for Occupational Safety and Health (NIOSH) recommends that occupational exposures to respirable coal mine dust and respirable crystalline silica* be controlled by complying with the provisions presented in this document. These recommendations are designed to protect the health and provide for the safety of workers exposed to respirable coal mine dust and respirable crystalline silica for up to 10 hr/day during a 40-hr workweek over a working lifetime. The information presented in this document demonstrates that underground and surface coal miners are at risk of developing simple coal workers' pneumoconiosis (CWP), progressive massive fibrosis (PMF), silicosis, and chronic obstructive pulmonary disease (COPD). Adherence to the recommendations in this document should prevent or greatly reduce the risk of adverse health effects in workers exposed to respirable coal mine dust and respirable crystalline silica. NIOSH recommends that preventive efforts be focused primarily on reducing worker exposures. Effective health and hazard surveillance and medical screening are also useful components of a comprehensive prevention effort.

Jan 1, 1997

By C. I. Pierce

The Bureau of Mines used an electrolytic tank model to investigate the response of guard electrodes of different dimensions under different simulated reservoir conditions. Sandstone disks from the Berea and Connellsville Formations were used as resistive beds in the model, and agar gel or water was used as conductive beds. In the experiments, bed thickness, hole diameter, mud resistivity, and bed resistivity were varied. The guard electrode is an excellent tool for determining true bed resistivity in the thin-bedded oil reservoirs of the Appalachian area. Vertical resolution and resistivity values are good when there is little or no invasion. Resistivity values are near true bed resistivity in beds thicker than about six hole diameters when the electrode-to-hole-diameter ratio is close to 1. However, low-resistivity muds cause false peaks to appear on the logs near bed boundaries in thick beds, and for resistive beds having a thickness approximately three to five times the hole diameter, apparent resistivities tend to be excessively high when mud resistivity is low.

Jan 1, 1966

By Cliff McCartney, Michael A. Trevits

The National Institute for Occupational Safety and Health (NIOSH) is conducting a program of research to evaluate and improve remote mine seal construction technology for mine fire control and suppression. The main focus of this work is to develop reliable technology that will remotely seal a mine opening from floor-to-roof and rib-to-rib. NIOSH, in partnership with Strata Mine Services Inc.1, is evaluating the capability of a two-component phenolic foam-based product, called Rocsil®1, that is intended for cavity filling, air and gas sealing, and consolidation of highly fractured strata. Rocsil® can be rapidly applied, has a quick cure time, a high expansion rate, good compressive resistance and excellent anti-static properties. When the resin and catalyst are mixed, an immediate foaming reaction occurs followed by rapid expansion up to 30 times the original volume. By virtue of its fire-resistance properties, Rocsil® foam has application for sealing underground mine areas undergoing heating from spontaneous combustion and it could be useful for remote mine seal construction to aid in mine fire control and suppression. This paper presents an overview of remote mine sealing technology, introduces the use of Rocsil® foam for remote mine seal installations, offers a case study of the use of this rigid foam material to remotely construct a temporary in-mine seal and discusses technology improvements. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of NIOSH.

By G. Asai

The Bureau of Mines has been engaged in a program to increase the utilization of chromium by providing samples to individuals and institutions requesting chromium for research investigations. This report consists of a tabulation of the disposition of chromium samples distributed from July 1953 through June 1961; 109 requests for chromium were answered by providing chromium as electrolytic plate, powder, or wrought forms. The demand for samples reached a peak in fiscal year 1959 and declined to a relatively low level in fiscal year 1961. The largest number of requests came from individuals engaged in mechanical property studies; there were also many requests from those concerned with vaporized metal and physical properties studies. Most noteworthy application for chromium was the experimental use of the radioactive form, Cr[51], in radiotherapy of cancer.

Jan 1, 1964

By Launa Mallett, PhD, Charles Vaught, PhD

This training material focuses on the content of emergency warning messages. Research has shown that when an emergency occurs, people often do not get the information they need for the purpose of taking appropriate action. This safety talk presents a procedure, using mental cues that can be used by senders and receivers of emergency warnings.

By A. U. Miller

"Ventilation is one of the meet important factors in mining, although until recent years less thought has probably been given to effective ventilation than to any other one phase of mining. In the past, very little, if any, attention was given air courses until they became so constricted by falls that the volume of air was greatly reduced; and, in addition, the stoppings and doors were so poorly constructed that only a very small percentage of air reached the face workings.As a matter of fact, mines have been visited where the volume of air being circulated in certain sections was much larger than in others, and where the management was striving to increase the flow of air in those sections with the least air current, believing the ventilation to be deficient. After sampling and analyzing the return air from the various sections in such mines it has been found that the quality of the air in certain places with the largest flow was more impure than in some of those with the least flow.In past years, practically all mine fans were operated by steam-driven engines supplied with steam from the mire boiler plant. No check was made on the steam consumption or the power cost of operating the fan, therefore the management had very little if any definite information as to cost of ventilating the mine.With the increased use of electrically-driven equipment in mines electricity is being used more and more to drive mine ventilating fans, and since in many instances the current is purchased from central power plants operators have come to realize that in many cases the cost of operating the fans is very high. Some engineers estimate that it ranges from 20 to 50 per cent of the total power cost of the mine. This information, together with the fact that mines are now being developed on a larger scale, requiring larger quantities of air for the men to dilute the gases liberated, has caused the large progressive companies to make, a more comprehensive study of mine ventilation, resulting in a decided improvement in the quality and quantity of air at the face workings, as well as reducing materially the ventilating costs."

Oct 1, 1930

By John Durkin

The Bureau of Mines has conducted field studies in coal mines through- out the United States to determine the effectiveness of electromagnetic techniques in locating miners trapped underground following a mine accident. Data from these tests have been used to generate models of expected signal and noise distributions as found above mines throughout the coalfields. These distributions have aided in placing the expected performance of a through-the-earth electromagnetic communications technique into a probabilistic framework. Results show that at a 10-pct false alarm rate, the expected probability of detecting a miner's signal from a depth of 1,000 ft is 54 pct; at 500 ft it is 95 pct. These depths exceed the actual depths of 90 pct and 50 pct, respectively, of U.S. coal mines. Sensitivity studies have shown that at a depth of 1,000 ft, for every 3 db of improvement in signal-to-noise ratio, the probability of detection increases 6 to 8 pct.

Jan 1, 1982

By A. Adams

The quality of hafnium metal produced by the Kroll process depends upon the purity of the hafnium tetrachloride. This investigation of methods for purification of hafnium tetrachloride was undertaken to aid in producing a higher purity hafnium metal than is currently produced by the Kroll process, The quantities of metallic impurities in hafnium metal were decreased by contact with molten alkali-metal chloride salt. Contact was achieved by a semicontinuous process of bubbling gaseous hafnium tetrachloride through a molten salt bath or by a batch process, first fusing the tetrachloride with a combination of alkali chlorides and then heating the mixture to sublime the hafnium tetrachloride. Low-melting mixtures of sodium, potassium, and lithium chlorides were used to purify hafnium tetrachloride. About 30 percent of the initial hafnium tetrachloride was trapped during purification with alkali- metal chloride salts. The 95-percent confidence limits (6)4 for the amount of oxygen decrease 60 and 34.3 parts per million when the batch purification is combined with a reduction so that both take place in the same equipment,

Jan 1, 1961

By T. A. Raczek

Materials for stronger ventilation tubing for underground use in hardrock mines were developed. The new material composites were evaluated in performance characteristics and compared to currently used materials. The materials were compared on tear, tensile, puncture and flammability properties. Based on cost versus performance data, a polyester film bonded to a polyester fabric was selected as the candidate material for field testing. Ventilation tubing fabricated from the selected material was field tested in two underground uranium mines for four-month periods. The test results indicated that the new composite showed an increase in useful life in the majority of applications, However, the cost performance ratio was not significantly improved to warrant commercialization of the product. When connected directly to some blowers, the material in close proximity to the blower deteriorated. However, material which was punctured or torn by mechanical means did not have further propagation of the tear. The high tear strength of the material prevented further damage. Improved methods of repairing inflated ventilation tubing were investigated and developed. All the repair methods were portable and self-contained. Repair kits based on adhesives, pressure sensitive tapes, and mechanical means were evaluated. Plier staplers and patch systems based on pressure sensitive adhesive proved to be most functional.

Jan 1, 1980

By M. S. Seehra, V. S. Babu, L. Farinash

"The diesel particulate matter (DPM), a constituent of the diesel engine exhausts, is known to be a potential carcinogen. 1- 3 Consequently, suitable methods to control/eliminate DPM have ·been under investigation in recent years. The DPM can be controlled by using fibrous ceramic traps. However, clogging of traps by DPM requires the impractical periodic trap replacement. Following the recent work by Garner and Dent,4,5 we are investigating the in situ use of microwaves to regenerate the ceramic traps, thereby eliminating the trap replacement step in this process. The use of microwaves instead of conventional heating for trap regeneration has the advantage of selective heating of the DPM instead of the trap, if the trap absorbs insignificant microwave power relative to the DPM. Also, the oxidation characteristics of the DPM are needed to understand fully this regeneration process.The rate of energy absorption P per unit volume of a sample is given byP = wE"" |Eo|2 • (1 )where w is the angular frequency, |E0|2 is the intensity of the microwave radiation, and E” is the imaginary part of the dielectric constant (E = E’ + iE”) . Thus measurements of E11 for DPM and ceramic trap material are needed to determine their capacities for microwave absorption. In this paper, we report these measurements carried out at · a frequency of 8.7 GHz. Following microwave absorption, the DPM is expected to oxidize. The oxidation characteristics of the DPM have been investigated using Fourier transform infrared (FTIR) spectroscopy of the evolved gases CO2 and CO and using thermogravimetric analysis (TGA). Finally, some information on the structure of carbon in DPM has emerged from the analysis of its x-ray diffraction spectra. Results of these experiments are reported in the following pages."

Dec 1, 1996

By C. W. JEFFERS

At its annual meeting on March 5, 1928, in Washington, D. C., the Joseph A. Holmes Safety Association gave to the Ford Collieries Co., Curtisville, Pa., a certificate of honor for "having worked 922,628 underground man-shifts from August 14, 1920, to December 31, 1926, producing 5,755,669 short tons of coal without a fatality." This remarkable record certainly deserved recognition. It developed that this company's freedom from fatalities continued until October 2, 1929, hence the full period during which no underground fatalities occurred was from August 14, 1920, to October 2, 1929, or 9 years, 1 month, and 18 days, the total tonnage being over 7,700,000. Table 1, shows the complete safety record of the Ford Collieries Co. since 1920 as given by the officials of the company. The first item in Table 1 shows a remarkable performance. This company since 1920 has mined 15 times more coal per fatal accident than the average pro- duction per fatal accident for the State of Pennsylvania in 1928 (255,257 tons). Excluding the two fatalities (one in 1922 and one in 1929) the severity rate for the same period has been 1.259 per thousand hours worked, a record of which the company may justly be proud. However, including the fatal accidents the rate is 2.407. This compares favorably with an average of 12.4 in 1928 for 66 mines in the National Safety Competition. The Ford Collieries Co. operates three mines located in the vicinity of Curtisville, Allegheny County, Pa. One of these mines, Benjamin No. 1, is idle at the present time. The officials are: A. R. Pollock, general manager, Curtisville, Pa., and C. W. Pollock, assistant general manager in charge of safety and operation.

Sep 1, 1930

By T. H. Ueng, S. D. Thompson, Y. J. Wang

"INTRODUCTION There is considerable interest among mining companies and government agencies in finding new ways to better control the generation and dispersion of respirable coal dust. Mine face ventilation generally has been considered the most effective tool for lowering the concentrations of respirable dust. Unfortunately, only a limited amount of research has been undertaken to determine the relationships between the various face ventilation parameters and the dust dispersion patterns. If these relationships are better understood, more efficient ways of controlling dust generation and dispersion may be evident. A practical and economical way to gain more in-depth understanding of these relationships is through scale model studies. Past research (1, 2, 3) has substantiated that scale models can be successfully used in studying ventilation parameters provided that geometric, kinematic, and dynamic similitues are maintained.To better understand face ventilation and dust dispersion, a 1/5 scale model of a room and pillar mine face was constructed. This model was then used to conduct experimental investigation on two ventilation parameters. The parameters which were examined included the line brattice distance from the face and the air quantity. The values of these parameters were varied in numerous experiments so that their effects on dust dispersion could be measured.The experiments of this study were unique in two ways. First, two different substances were used to simulate the respirable coal dust. Experiments were conducted with a tracer gas (methane) serving as the dust simulation substance. They were then repeated with an actual dust (Arizona Road Dust) replacing methane as the dust simulating substance. In previous scale model studies, the dust simulation substance has been limited to a tracer gas such as methane. The validity of using a tracer gas to simulate dust is not clearly known yet. The other unique thing about these experiments was the number of points measured for methane (or dust) concentration. Twenty five points in a grid arrangement were measured during each experiment of this study. The number of points measured for concentration in other studies has generally been very small (often 2 to 4). It is difficult to obtain an accurate assessment of how the ventilation parameters are effecting dust dispersion when only 2 to 4 points are measured."

Mar 1, 1989

By J. V. Batty

In the course of the investigation of manganese mineral occurrences in the United States, Bureau of Mines examining engineers collected several lots of ore from the Black Rock, Kramer, and. Morgan-Cromar properties, Tooele and Juab Counties, Utah. Extensive laboratory tests were made to determine the amenability of the ores to standard ore-dressing methods of concentration. The Black Rock claims 1 and 2 are 42 miles northwest of Jericho, Tooele County, Utah. A. J. Huber of Salt Lake City and Ross Rydalch of Tooele, Utah, are the owners. The deposit-is reported to be a definite manganese fissure vein in quartzite along which considerable shearing and cross fracturing have occurred. Laboratory work was conducted on a 2-ton sample of run-of-mine ore procured by a Bureau of Mines examining engineer and two smaller, higher-grade samples submitted by the owners as a result of later development. The Kramer deposit is described as a bed of manganese oxides in quartz. The property is being worked by L. E. Kramer, Tooele, Utah, and is 41 miles northwest of Jericho) Tooele County, Utah, approximately 1 mile north of the Tooele-Juab County line. A 1-ton run-of-mine sample was submitted for testing by the examining engineer.

Jan 1, 1952

By Louis C. Brichta

The rapid; depletion of' known high-grade ore deposits in the Tri -State lead-zinc district and the recognized need for the development of additional reserves led the Bureau of Mines to make preliminary examination of sites possibly adaptable to low-cost open-pit mining methods. Abandoned mines whose ore deposits were known to have occurred at shallow depths naturally presented favorable test points for the development of possible open-pit orebodies. The Lone Elm mine was in this category.

Jan 1, 1949

By G. R. Hopkins

According to reports received by the Bureau of Mines, Department of Commerce, as of January 1, 1929 there were 413 completed refineries in the United States, with a total daily crude-oil capacity of 3,509,540 barrels. In addition, 14 refineries, with a potential capacity of 99,000 barrels, were being constructed. Of the completed refineries, 341, with a capacity of 3,325,890 barrels, or 95 per cent of the total capacity, were in operation; and 72, with a capacity of 183,650 barrels, or 5 per cent of the total, were shut down. The improved condition of the refining industry in 1928 was indicated in several ways; namely, in an increase in the total capacity of the completed plants, in the opening up of a few plants which were shut down during 1927, in a decrease in the number of plants dismantled, and in an increase in the number of plants under construction. The majority of the refiners have followed a steady expansion program commensurate in most cases with the increase in demand for petroleum products. Obsolete equipment has been dismantled and modern equipment has been installed, with the net result that the total capacity of the completed refineries in the United States has shown a steady increase since January 1, 1918, the date of the first Bureau of Mines survey. Between January 1, 1928, and January 1, 1929, the number of completed plants fell from 423 to 413, but their total capacity increase 259,160 barrels, or 8 per cent. This compares with an increase in runs to stills of domestic and foreign crude petroleum of 10 per cent, and of domestic crude alone of 7 per cent.

Jan 1, 1929

By K. E. Stanfield

[Asphalt ~~d road oil ar8 the principal products manufactured from Wyor.1in~ Ilblack oilo" \r,hich, beca.use of th?lir hig.~ E\.sphal t and hig} sulfur COi.1Jce~1t, .!?re difficult e':ld costly to refine into hi?;h-gra.de motor f 101s, burning oils. and lucri ants by presont mothods. Accordin~ly. the demand for truHle asphaltic renidl urn for the construction of roade aJ1.d other uses is 3. controlling factor in the quantity of crud~ oil prod ICed. The increasiilg -u.tilization of special aST>ha.lts as ine}""Pensive bonding, in-]

Jan 1, 1941

By H. W. St. Clair

This study of the rate of evaporation of zinc was undertaken as a part, of a general investigation on refining mixtures of metals resulting from melting reclaimed scrap. One of the methods by which the more volatile metals, such as zinc, magnesium, and cadmium, may be separated is by distillation. Distillation may be carried out at lower temperatures if it is done in an evacuated enclosure. The immediate purpose of the present investigation was to determine accurately the effect of temperature, pressure, and other factors on the rate of evaporation of zinc.

Jan 1, 1950