Search Documents

By R. H. Harrison, D. R. Douslin

The thermodynamic properties H - H° , (H - H° ) /T , S - Sideal , S - S° Fide al F - F° , (F F° ) /T , and activity coefficient Y for perfluorocyclobutane were calculated as functions of temperatures ( 115.22 ° to 350 ° C) and molal density (0.75 to 6.5 moles / liter ) . Improved analytical and graphical correlating techniques are described .

Jan 1, 1964

By X. C. Shi

Bacterial mutagenicity and mammalian cell chromosomal and DNA damage in vitro assays were performed on a diesel exhaust particulate material (DPM) standard in two preparations: as an organic solvent extract, and as an aqueous dispersion in a simulated pulmonary surfactant. U.S. National Institute for Standards and Technology DPM SRM 2975 expressed mutagenic activity in the Salmonella reversion assay, and for in vitro genotoxicity to mammalian cells as micronucleus induction and as DNA damage in both preparations: as an acetone extract of the DPM mixed into dimethylsulfoxide, and as a mixture of whole DPM in a dispersion of dipalmitoyl phosphatidyl choline. Dispersion in surfactant was used to model the conditioning of DPM depositing on the deep respiratory airways of the lung. DPM solid residue after acetone extraction was inactive when assayed as a surfactant dispersion in the micronucleus induction assay, as was surfactant dispersion of a respirable particulate carbon black. In general, a given mass of the DPM in surfactant dispersion expressed greater activity than the solvent extract of an equal mass of DPM.

Jan 1, 2009

By M. E. Tyrrell

Magnesia spinel (MgO.Al203) recovered from dusting slags in the system MgO.Al203-2Ca0.SiO2 is in the form of single crystals most of which will pass 35-mash. This investigation was undertaken by the Bureau of Mines to evaluate the concentrates as a refractory raw material. Three specific types of refractory bricks were studied: (1) dense, (2) lightweight bubble, and (3) insulating. Test specimens ware fabricated 1 by dry pressing, fired to 1,675° C., and tested by procedures common to the industry. The concentrates produced a refractor, having satisfactory density and mechanical strength; however, spinal is sensitive to thermal shock and the possibility of producing a spall-resistant brick using aggregate of such small grain-size must be considered remote. Lightweight refractorias fabricated of spinel bubbles were the most promising of the types tested. They were 30 percent lighter in sight than the dense refractory, their mechanical strength was good, and definite superiority in thermal shock resistance was indicated.

Jan 1, 1962

By Arthur L. Murray

"While serving as surgeon with rescue car No 11 of the U. S. Bureau of Mines, the writer visited the principal metal-mining camps of Utah during the latter part of 1919. In visiting the mines, meeting and conversing with miners, and talking over the medical situation with physicians in the various camps, the number of cases of lead poisoning encountered was great enough to attract attention.With a view to procuring more definite information as to the number and distribution of cases of lead poisoning throughout the State, a study of the records of the State Board of Health was undertaken. Utah had no ordinance re¬quiring the reporting of occupational diseases, so it was not possible to secure data an cases A study of the mortality records by years gave the following results.:Year Deaths from lead poisoning.1910,11911,01912,21913,11914,61915,41916,11917,31918,11919,2These few deaths would seem to indicate a fairly low case rate, but when it is realized that lead poisoning is rarely an immediate cause of death and that the train of sequelae in this disease frequently leads to chronic involvemeets of the digestive, nervous, circulatory or genito-urinary systems, it is apparent that the number of deaths showing lead poisoning as the cause can not be taken as an index of the cases prevalent. The time elapsing between the presence of the active signs of lead poisoning and the terminal illness from pathologic conditions excited by lead absorption may be years, and the initial cause, lead poisoning, is frequently lost sight if entirely, hence the death certificate shows no evidence of the primary cause."

Aug 1, 1921

By Curtis D. Edgerton

The Pittsburgh Mine Map Repository of the Bureau of Mines serves as a basic reference file for the archival preservation of mine map data of mines east of the Mississippi River. About 22,000 of an estimated 500,000 available mine maps have been microfilmed A computerized index serves as the mechanism for retrieval of any microfilmed mine map. The operation, equipment, and index are described in the report.

Jan 1, 1974

By Dean H. Ambrose

The U.S. Bureau of Mines recently developed computer graphics simulations to characterize mining scenarios, specifically for room-and-pillar mining operations in a three-entry longwall development section. These simulations compare productivity between shuttle car and continuous haulage systems concepts. One of the continuous haulage systems concepts has bolting capabilities that supplement haulage function. Simulations showed the continuous haulage system to be more time efficient than the shuttle car system. Researchers can reuse the simulation code (e.g., mining rates and equipment capacities can be changed) should investigators care to compare production of other mining scenarios. computer simulation, found computer model modification flaws and mining scenario conceptual errors. The fundamental rationale for three-dimensional computer is to cheaply, easily, and quickly obtain information about operation and of a current or proposed mechanical coal or metal/nonmetal mining system. This report documents the computer graphics model and simulation developments and discusses some of the results and observations from the simulations.

Jan 1, 1994

By E. O. Wagner, Manuel Gomez, W. S. Landers

The Bureau of Mines studied coking rates of a special Columbia - Geneva six - coal blend to establish the effect of the coking rate on coke properties . The tests were conducted in a 500 - lb , 14 - in experimental slot oven at essentially constant conditions of blend composition , size distribution , surface moisture content , and bulk density . The coking rate was varied as a function of oven flue temperature . Coking rates within the range of 0.56 to 1.35 in/hr were achieved . Increase in the coking rate decreased the size of the coke . The stability factor of the coke showed no significant change with coking rate until coking rates greater than 1.0 in/hr were reached , after which a decrease in the stability factor was observed . The apparent specific gravity increased to a maximum value at coking rates approaching 1.1 in/hr and decreased sharply with further increase in the coking rate . Coke parameters correlated well with the coking rate .

Jan 1, 1963

By A. F. Jolly

In an effort to better predict the useful service life of friction rock stabilizer mine roof bolts in coal mine environments, the Bureau of Mines has evaluated the corrosion resistance of stabilizer steels in air-saturated and deaerated waters from seven Eastern and Midwestern underground coal mines. Accelerated electrochemical corrosion tests were used to estimate corrosion rates for the two high-strength, low-alloy (HSLA) steels used to fabricate Split Set stabilizers and for galvanized steel. Long-term static-immersion weight-loss tests were also conducted with the HSLA steels. Corrosion rates developed from the weight-loss tests (steady-state air dissolution) were roughly comparable to rates determined from electro-chemical testing in aerated waters. Although the highest rates occurred in waters with the highest chloride contents, rates in the other waters were low (<2.0 mpy) and exhibited little correlation to the widely varied chloride contents of the waters. The generally low corrosion rates are attributed in part to the tendency to deposit a protective CaC03 film, reflecting susceptibility to carbonate precipitation as indicated by positive Langelier (saturation) index values for the waters. With one exception, corrosion rates for the galvanized steel were (2.0 mpy. Rates with aerated waters were higher than those with deaerated waters. Pitting tendencies of the steels were also estimated.

Jan 1, 1987

By L. T. MCELVENNY, Robert B. McElwaine, M. Clair Smith

Production of mercury from the cinnabar deposits of the southwestern Arkansas mercury district began in 1931 , reached its peak in 1942 , and ended in 1944. The mines are now idle . Virtually all the cinnabar was obtained from deposits in a belt , about a mile wide , of steeply dipping sandstone beds in the overriding blocks of three thrust faults . The belt was productive for a length of about 27 miles eastward from eastern Howard County, through Pike County, into Clark County . During the early life of the district, Federal agencies watched and recorded its progress as a contributor of a strategic metal, and later, during the war, conducted investigations designed to advance its development . In 1941 , the Bureau of Mines and the U. S. Geological Survey cooperated in investigations on eight mineralized areas in the western part of the district , to wit : Hales mine , U. S. mine , Lulu Bell property, Hopkins Hill , East Gap Ridge , Gap Ridge , Parnell Hill , and Section 17 mine area . U. S. Geological Survey prepared both surface and mine maps and designated the areas to be investigated ; the Bureau did the drilling , trenching, and sampling involved in the investigations . Twelve holes , aggregating 3,539 feet of bore , were diamond drilled on six properties ; 5,309 linear feet of surface trenches were bulldozed in six areas and 19 samples taken from them ; and 86 underground channel samples were cut in two adits on one property . In 1944 , the Bureau of Mines measured mine dumps and calcine dumps in the district in an investigation of their mercury content . Two mine dumps and one calcine dump were sampled . The data pertinent to the work done by the Bureau are included in this report .

Oct 1, 1950

By P. G. Clites

This bulletin summarizes the results of Bureau of Mines research on the development of the inductoslag melting process. Inductoslag melting is an induction melting technique using a segmented, water-cooled, copper crucible. The process was developed as part of the Bureau&apos;s work on effective utilization of reactive metal scrap, and the process has been applied to melting Ti, Zr, Cr, Co, Fe, Ni, and V. Construction details are given for the segmented crucibles and for both an ingot furnace and a casting furnace. The melting process is described, and results of tests conducted with a variety of reactive metals are given.

Jan 1, 1982

By E. G. King

In continuation of the study of thermodynamic properties of the common interoxidic compounds of ferroalloy elements, this report gives the results of low-termperature heat-capacity measurements and entropy evaluations of the monotungstates of sodium, magnesium, and calcium. Previous reports4 5/ of this laboratory dealt with low-temperature heat capacities, entropies, and heats of formation of the sodium vanadates. Heat-capacity measurements of the monotungstates of sodium, magnesium, and calcium (Na2W04, MgW04, and CaW04) were conducted throughout the temperature range 51° to 298° K. The entropies at 298° K. were evaluated and then combined with entropy data for the elements and oxides to obtain entropies of formation. This information is an essential part of the data needed for thermodynamic appraisals of chemical reactions of these substances. No similar data for any tungstate are to be found in the literature.

Jan 1, 1961

By Gary P. Sames

This report discusses some practical applications of a geotechnical investigation conducted by the U.S. Bureau of Mines that can help mine operators meet revised Federal regulations in their roof control plans. The investigation, designed to characterize roof conditions near the coalbed outcrop in drift coal mines in eastern Kentucky, revealed that weathered stress-relief joints near outcrop are crucial ground control factors in the region. The joints&apos; origin and character were determined through underground mapping of many joints in coal mine roof and detailed observations and measurement of joint trends and physical characteristics in widely separated strip mine highwalls and roadcuts. This resulted in an understanding of stress-relief-joint patterns and the effect of various rock types on the intensity of weathering in the joints. That information is used in this report to show how stress-relief joints contribute to roof failure and how, through improved roof support and mine planning, safer roof support plans can be developed.

Jan 1, 1992

By F. J. Palumbo

Effective recycling or disposal of flue dusts is a continuing problem for copper, brass, and bronze smelters. Over 300,000 short tons (st) of dust is generated annually by U.S. secondary copper, brass, and bronze smelters. The Bureau of Mines has developed an alkaline leach method for recovering metal values from copper converter flue dust containing zinc, tin, lead, and copper. The dust was leached with a hot solution of ammonium chloride and ammonium hydroxide to solubilize ZnO. All of the tin (as Sn02) and the metallic copper, lead, and zinc, as well as possible insoluble compounds of each, report to the residue. Dissolved copper and lead salts are removed from the leachate by cementation with granular zinc. Zinc oxide is precipitated by diluting the leachate with water. The tin-rich (9.8 pct) residue has a ready market. The cement product is recyclable to the smelting operation. The ZnO is at least 97 pct pure and has potential marketability.

Jan 1, 1985

By H. R. Beard

The citrate process for sulfur dioxide emission control was developed in pursuit of the Bureau of Mines goal of minimizing the adverse environmental impact of mineral-processing operations. This publication describes the gas analysis procedures used during development of the process. The research required the capability to analyze SO2, H2S, CO, CO2, COS, volatile hydrocarbons, NO, NO2, O2, N2, and H2. The methods described include gas chromatography, electrochemical detection, infrared spectroscopy, and the use of a computer program to predict the product composition in complex reactions. Laboratory and pilot plant applications are discussed.

Jan 1, 1979

By Scott Turner

We have gathered here in Pittsburgh, at the Nineteenth Annual Safety Congress, in order to advance the cause of safety. Although my personal inter- est in this movement alone would have been sufficient to insure my presence here, specific duties have brought me to this congress in an official capacity. My responsibilities as the head of the United States Bureau of Mines, which makes the promotion of safety in the mining and allied industries one of its major activities, necessitate my attendance. My obligations as president of the Joseph A. Holmes Safety Association, an organization closely allied to the bureau and which has for one of its objects the public recognition and reward of outstanding achievements in safety, require that I be present at this time. This morning, my job is to present the Holmes safety certificate to the Lehigh Portland Cement Co. First I will remind you of the nature of this safety association, named in honor of the first director of the Bureau of Mines. After Mr. Holmes' death, in 1915, a number of influential organizations banded together to commemorate the name of this leader in the conservation of human life. In order that you may appreciate the significance of an award by the Joseph A. Holmes Safety Association, I shall read you the list of 24 national organizations which comprise its membership:

Nov 1, 1930

By M. M. Jones

Natural brines are potential domestic resources of minerals. The brines of Searles Lake, CA, for example, contain an estimated one-fourth of our current reserve of tungsten. A key to Bureau of Mines research to recover this critical mineral is the ability to quantitatively measure concentrations of particular constituents in the large number of brine samples and process solutions produced under a multiplicity of test conditions. This paper describes procedures used to determine arsenic, boron, phosphorus, silicon, and tungsten in these solutions by simultaneous inductively coupled plasma spectrometry. A variable in-ternal standard method was used to compensate for tungsten interference on the other analytes in tungsten concentrates, and matching standards were used to determine tungsten in raw brine. Other solutions were analyzed using normal techniques. Analytes were determined down to 1 mg/L with an average precision of 2.5 pet relative standard deviation. Accuracy, estimated using synthetic solutions and by comparison with values obtained by other methods, averaged about 2.5 pet. The methods were rapid, required little sample preparation, and provided the needed sensitivity.

Jan 1, 1985

By H. H. Schrenk

Much has been written and said concerning tables of permissible or maximum allowable concentrations of various toxic substances in air, but not enough attention has been given to their limitations and how to use them intelligently . There is a tendency to place too much reliance on figures , with little or no consideration of their real meaning . The repeated publication of a figure often adds significance to it far beyond that intended by the original author or publisher . How are these figures referred to as "maximum allowable concentrations " established? What is their real meaning? To answer these questions it is necessary first to define maximum allowable concentration . The usual definition is somewhat as follows : "The average concentration to which an industrial worker can be exposed for 8- hours daily for an indefinite period without injury or occupational disease . This definition is made up of the following items : ( 1 ) Average concentration, ( 2 ) 8 - hour day , ( 3 ) indefinite exposure period , and ( 4 ) lack of injury or occupational disease . There is some controversy regarding item ( 1 ) , items ( 2 ) and ( 3 ) are usually though not invariably accepted , and there is definite disagreement regarding the interpretation of item ( 4 ) . . To reach a more satisfactory interpretation of maximum allowable concentration , attention is directed to ( 1 ) the development of tables of maximum allowable concentrations , ( 2 ) criteria on which limits are based , and (3 ) methods used to obtain data on which limits are based .

May 1, 1948

By Nadia C. Miller

In situ stope leaching is an innovative mining system that reduces the surface impacts of conventional underground mining. As in any leaching operation, stope leaching requires hydrologic site characterization and control of leaching solutions. Several tracer tests, using sodium chloride (NaCl) in various concentrations, were conducted by the U.S. Bureau of Mines (USBM) in an underground experimental stope to simulate a leaching environment. The tests were conducted in fractured crystalline rock that was partially water-saturated. As tests progressed, the surrounding fractures became more saturated. A predominant flow direction away from the stope was found during testing. Testing procedures, results, and a remediation plan for in situ leaching based on field observations are presented in this report.

Jan 1, 2010

By Richard L. Unger

The U.S. Bureau of Mines has designed, fabricated, and tested a prototype track maintenance vehicle for underground coal mines. The vehicle uses a stiff rotating brush to clean the track so that a visual inspection is possible. It is also equipped to measure track gauge and cross-level. The objective of this report was to describe the track maintenance vehicle and detail the results of investigations into present underground track inspection procedures and cleaning technologies, which led to the development of the prototype. Recommendations are made concerning the integration of components of this prototype vehicle into current track cleaning and inspection systems used in underground mines.

Jan 1, 1984

By R. V. Ramani

In this the available information friction factors and leakage report, on characteristics are reviewed and summarized. The use of Penn State Mine Ventilation Simulator (Volumes II and III of the Final Report) to analyze the sensitivity of the ventilation system to the changes in leakage and friction factors is discussed with examples. In simple ventilation systems, the results of changes in leakage and friction factors can be easily solved and explained by the laws of air-flow. In complex systems, with fixed quantity branches and multiple sections, the effect of changes in leakage and friction factors cannot be generalized. This study points out the importance of good input data for obtaining reliable information from computer analyses and demonstrates the application of simulators to analyze the effectiveness of ventilation systems. An extensive bibliography on friction factors, leakage characteristics and ventilation economics is included.

Jan 1, 1977