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By Richard J. Bielicki

The possibility of replacing the brattice cloth closest to the coal mine working face with an air curtain mounted on top of a continuous-mining machine or with a diffuser fan was explored by the Bureau of Mines. Preliminary tests conducted at a full-scale model working face with the brattice end set at 18 feet showed that the air curtain improved face ventilation only slightly and was not nearly as effective as placing the brattice at 10 feet. A 2,000-ft3/min diffuser was more effective than the air curtain. It is concluded that the air curtain probably could not function as a line brattice extension, although the diffuser fan may have some potential.

Jan 1, 1975

By E. H. Denny

A most interesting safety record has been made by the Colorado Fuel and Iron Co. s. Robinson ho. 1 mine located at Walsen, Cola. Mr. J. L. McBrayer has been superintendent of the Robinson No. 1 and 2 mines for the past 2 1/2 years, and Mr. David Muir has been foreman of the Robinson No. 1 mine since June, 1913. The last fatal accident at Robinson No. 1 mine occurred on July 27, 1915, and the tonnage produced at this mine since July 28, 1915, has been as follows:.

Jan 1, 1929

By Lucia Kuizon

The Morongo Wilderness Study Area (WSA) is in south central San Bernardino County, California. U.S. Bureau of Mines examined the area during the fall of 1983. No mines, prospects, leases, or mining claims were found in the WSA. There are no known mineral deposits within the study area boundaries. Sand and gravel in the area is suitable for many types of construction uses, but similar and larger deposits outside the WSA are closer to markets. No energy resources have been identified in the WSA.

Jan 1, 1984

By H. H. Schrenk

[A calorimetric method3/ for the determination of benzene in amounts as low as 0.001 m has been developed recently at the U.S. Bureau of Mines Pittsburgh Experiment Station by the authors, with the assistance of chemical personnel from the Allegheny County (Pa.) Relief Works Division. The method is based on the direct nitration of either liquid or gas - phase benzene, followed by neutralization, extraction with butanone, and final treatment with sodium hydroxide which produces a violet color. The color is matched with color standards of known values. Although the method is adaptable to many conditions the primary objective was a procedure that would be suitable for hygienic investigations.]

Jan 1, 1935

By M. H. Stanczyk

Bench-scale laboratory tests were made by the Bureau of Mines of a segregation-flotation concentrate, assaying 20.43 percent copper, to investigate the influence of various ratios and concentrations of ammonia and carbon dioxide on copper extraction. Leaching the concentrate with a solution containing 900 pounds of ammonia and 360 pounds of carbon dioxide per ton of feed, followed by washing the leach residue with 1.75 tons of a 10-percent solution of ammonium carbonate and about 1 ton of water (as steam) per ton of solids, resulted in a copper recovery of 96.3 percent. Resegregation and flotation tests of the washed residues revealed that 85 percent of the copper in the residue could be recovered. Steam distillation tests of a typical ammoniacal leach liquor, assaying 39 grams copper, 105 grams ammonia, and 77 grams carbon dioxide per liter, recovered over 99 percent of the copper as a mixed oxide-carbonate precipitate. The ammonia losses in leaching, filtering, washing, and distillation were 0.12 pound per pound of copper recovered in the precipitate. Calcination and subsequent hydrogen reduction of the precipitate yielded a metallic copper powder assaying 98 percent Cu, 0.87 percent Si02, 0.10 percent MgO, 0.54 percent CaO, and 0.41 percent R203.

Jan 1, 1961

By H. P. Rue

The Bureau of Mines has recently collected two samples of crude oil from wells in the Greasewood Flat, area of northeastern Colorado. Sample 31310 was taken from the Continental Oi1 Co.'s well Briggs No. 1 which came in on September 27,7.931, with a maximum production of 940 barrels per day. Sample 31311 was taken from the Reiter-Foster Oil Co.'s well Ida Johnson No. 1 which came in on August 24, 1931 with a maximum production of approximately 1000 barrels per day. These two samples of crude oil are typical "intermediate base" crude oils according to the classification defined by Smith and Lane. The characteristics of these two samples, as shown by the Hempel analyses, indicate that they are almost identical. They have a very low sulphur content, and the residuum has a low carbon-residue content which would indicate that they are excellent crude oils for refining. Crude oils yielding a residuum which has a carbon-residue content of 4 per cent or less usually make good material for the manufacture of cylinder stocks. The pour points of the samples and the cloud test of the fractions obtained from the vacuum distillation indicate that the Greasewood Flat oil contains considerable wax. The high wax content would cause some difficulty in transmitting this oil through a pipe fine during extreme cold weather.

Jan 1, 1932

By Lucia Kuizon

Results of the U.S. Bureau of Mines' survey of mineral resources in the Cuyama RARE II study area indicate there is no potential for metallic minerals and low potential for the development of gypsum resources. There are no producing or developing mines within the study area. The Santa Barbara Canyon Prospect contains 30,000 tons (27,000 t) of subeconmic gyspum resources, the Wagon Road Prospect 276,000 tons (250,000 t), and the Brush Fence Canyon 61,000 tons (55,000 t). Most of the resource in the Brush Fence Canyon Prospect is outside the area. Gypsum was not observed at the Cuyama River deposit. Present gypsum and gypsite requirements are being met by larger deposits closer to major markets. INTRODUCTION Location (USGS) Present and Previous Studies (to be combined with USGS section) The Bureau of Mines reviewed literature and mining claim records for the study area. A field examination of known mineral properties was made in October 1980; it included mapping and sampling of prospects to evaluate the economic potential of mineral resources.

Jan 1, 1981

By Robert L. Thorne

As an integral part of the investigation of critical and essential minerals in Alaska , the Bureau of Mines examined the lead deposits in the Slana area . Four examinations were made during June , July, and August 1945 in the 200 - square -mile area immediately northwest of Slana . The settlement of Slana lies near the conflux of the small Slana River with the mighty Copper River less than 60 miles southwest of Tek Junction on the Alaska Highway . Travel through the area and the examination of the properties were conducted by a three-man crew consisting of the author , a caterpillar operator , and a laborer . An RD6 caterpillar , equipped with blade and winch , was used in breaking trail and freighting through the country . Supplies and equipment were loaded on a 7- by 14 -foot , double - end , go -devil , which was hauled by the tractor .

Nov 1, 1946

By E. D. Gardner

"The Bureau of Mines has studied blasting practices in metal mines of the Southwest. The investigation of blasting drift rounds showed among other results, that cut-holes in ground difficult to break could be chambered to advantage under some conditions.In open--cut mines, chambering nearly all holes before blasting is the common practice. Two or more free faces are generally maintained in this type of work, and the amount of explosive necessary to break any bench or bank can usually be estimated from the yardage to be moved. However, in blasting drift or tunnel rounds only one free face is available before the cut-holes are shot, and the quantity of explosive required is generally ascertained best by trial.In addition to being the most difficult to break, the cut-holes are the most important of a drift round. When the cut-holes ""break bottom"" less work is required of the other holes, and a full break of the round is generally obtained. In ground difficult to blast, extra care and expense are justified to insure that the cut-holes ""break bottom.""At many mines the work is so organized that all blasting is done at the end of the shift, and a decided advantage would have to be gained to make chambering of the cut-holes economical. Also, in many mines blasting during the shift would not be practical. One or two holes could probably be drilled during the time necessary to do the chambering. However, under certain special conditions, such as in small operations or those where ""leasers"" or contractors are working, drill holes could be chambered should there be an advantage in doing so. Moreover, in some mines it might be practical to chamber the cut-holes at the lunch hour. In ordinary rounds the cut-holes are generally drilled by noon. It would not be necessary to tear down the drill or remove tools from the face to do this work of chambering."

Feb 1, 1928

By S. B. Levin

"INTRODUCTION An exposure of large beryl crystals in pegmatite on Beryl Mountain, in Sullivan County, N. H., was the basis for investigation by the Bureau of Mines to determine the extent of the beryl mineralization and to expose other parts of the same zone that were favorable for additional beryl-rich shoots. Testing by surface cuts, trenching, and tunneling was conducted by the Bureau of Mines from August to December 1943.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to the national security and economy. The Mining Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, O. C. Ralston, chief, analyzes samples and makes beneficiation tests. The field work was supervised by Paul M. Tyler, regional engineer, and John D. Bardill, district engineer. S. B, Levin was in direct charge of the project.LOCATION AND ACCESSIBILITYThe deposit is on the northeast slope of Beryl Mountain, 1 mile south of the village of South Acworth. The village, on State Highways 101 and 123a, is 12 miles northeast of Bellows Falls, Vt. The deposit is reached from South Acworth over a gravel-surfaced road and about 1,000 feet of good truck trail (fig. 1).The nearest railroad siding is at Cold River, on the Boston & Maine Railroad, where there is also a fairly modern, but now idle, feldspar mill."

Mar 1, 1948

Develop a method for recovering phosphate from a wide variety of complex western phosphate materials, including low-grade ores, tailings, and unused fines. Approach A flotation technique is used for this broad type of extraction. The method includes depression of phosphate minerals and anionic flotation of carbonate minerals, followed by cationic flotation of silicate minerals. How It Works A slurry is prepared for flotation by sizing to remove a low-grade, high-impurity slime fraction. Depending on the material, further sizing and/or grinding steps may be used to produce a size concentrate or to remove gangue. The flotation feed is conditioned with H2SiF6 and a fatty acid emulsion. The H2SiF6 is absorbed chemically to the phosphate mineral surface, making it strongly attracted to water and preventing adsorption of the fatty acid. Under these conditions, the fatty acid is a selective collector for carbonate minerals, which are removed as a froth product. Next, the silicates are floated with an amine reagent added directly to the slurry without additional pulp preparation.

Jan 1, 1982

By Lloyd A. Morley, Robert Stefanko

Table

Jan 1, 1974

By H. H. Schrenk

[A colorimetric method5/ for the determination of benzene in amounts as low as 0.001 mg has been developed recently at the U.S. Bureau of Mines Pittsburgh Experiment Station by the authors, with the assistance of chemical personnel fro a the Allegheny County (Pa.) Relief Works Division. The method is based on the direct nitration of either liquid - or gas - phase benzene, followed by neutralization, extraction with butanone, and final treatment with sodium hydroxide which produces a violet color. The color is matched with color standards of known values. Although the method is adaptable to many conditions the primary objective was a procedure that would be suitable for hygienic investigations. The development worth included a study of possible interference by chemicals that be present in those situations in which the method. would be employed. In this study it was found that a specimen of hexane prepared by the Gulf Research Laboratory, Pittsburgh, by fractionation of West Virginia natural gas gave positive result for benzene, whereas a specimen of pentane prepared in the same manner showed only a trace, and specimens of n -heptane and octane (2,2,4 trimethylpentane) supplied by Eastman Kodak Co. save a negative result. According to information obtained from the Eastman Kodak Co. the latter two compounds were highly purified, the n-heptene being prepared from line and the octane synthesized in the laboratory. On nitration of a larger amount of tae natural hexane a visible quantity, of needlelike crystals which resembled those of m-dinitrobenzene was obtained. The hexane from this nitration was recovered by distillation and again nitrated, but no crystals or colorimetric indication of benzene was obtained. This imitated that the specimen of natural hexane contained a substance which at least had the chemical behavior of benzene.]

Jan 1, 1935

Minimize the effects of underground mine conveyor belt fires by developing methods to prevent automatic fire suppression system failures. The Problem Fire protection is achieved by prevention, early detection, and planned fire-fighting response. Automatic fire suppression systems are one form of planned fire-fighting response. When these systems are properly designed, installed, and maintained they can effectively control fires. Conveyor belt fires account for about 20% of underground coal mine fires. Fire protection requirements have been established for underground locations because of potential for start and spread of fire and the restricted personnel egress in a fire situation. Belt conveyor systems arc potentially dangerous because of the high fire incidence rate, high temperatures, dense smoke, toxic gases, and rapid flame-spread rate. While investigating the conveyor fire suppression problem, the Bureau identified automatic fire suppression system reliability as a potentially serious deficiency within the mining industry. Table 1 lists common failure modes fur three Fire suppression system types. This table summarizes findings of Mine Safety and Health Administration electrical inspectors responsible for inspection of belt protection automatic fire suppression systems. Batteries, contact points, control wires, and electric servocontrols are all prone to failure. Figure 1 shows rock-dust-contaminated relay contact points. This condition is dangerous because of the chance of intermittent failures, which might allow systems to pass annual functional testing, yet fail during actual fire emergencies.

Jan 1, 1989

By Roy H. Grau

Increased awareness of a healthy work environment is common to all industries and the stone industry is no exception. The presence of operating diesel equipment, welding, stone production blasting, and silica dust in a working environment all contribute to air quality issues in underground stone mines. Particularly recognized is the exposure of workers to diesel particulate matter (DPM). Recent regulations call for a DPM standard of 160TC ug/m3 (TC = Total Carbon). The National Institute for Occupational Safety and Health (NIOSH) has conducted research to improve the ventilation of these mines and consequently reduce the exposure of workers to harmful airborne contaminants. The results have shown that the ventilation of underground stone mines can be significantly enhanced using improved ventilation controls and techniques. Large-opening stone mines present specialized ventilation challenges because their entries are much larger than in other types of mines. Most stone mines have entries about 40 feet wide and up to 30 feet high, with bench areas that may extend even higher. These large entries present the positive opportunity to move large air quantities at relatively low mine fan pressures resulting in lower fan horsepower and reduced operating costs. However, the difficulty in ventilating large-opening mines is that even with large air volumes, the air velocity is often less than 100 feet/minute. Higher ventilation velocities more quickly dilute and remove contaminants from the face areas. Higher ventilation airflow velocities can be achieved by effective ventilation planning and proper choice of ventilation fans.

Jan 1, 2009

By G. W. Jones, R. E. Kennedy

Most gasolines and naphthas are mixtures of paraffin- series hydrocarbons and comprise such substances as pentane , hexane , heptane , octane , and others up to perhaps dodecane . Many of these hydrocarbons , when mixed with the proper proportions of air and ignited , are highly explosive . It is due to this characteristic that gasoline has become so important as a fuel in internal -combustion engines . Gasoline and naphtha also are used in the industry as solvents and cleaning agents . Because of their explosive properties they are dangerous to use unless the composition is so chosen that the vapor pressure of the mixture is not high enough to produce explosive mixtures with air at the temperature at which they are used . Hydrocarbon mixtures may be made less hazardous by adding some incombustible liquid , such as carbon tetrachloride . Barrier reports the amount of carbon tetrachloride that must be added to different naphthas to render such mixtures free from fire and explosion hazards . He found that the amount of carbon tetrachloride that must be present in the final mixture of naphtha and carbon tetrachloride varied with the density of the naphtha . Of the naphthas tested the amount of carbon tetrachloride necessary to render such mixtures free from fire and explosion hazards ranged from 30 to 70 percent . .. Determination of the fire and explosion hazards of carbon tetrachloridehydrocarbon mixtures would be easy if the boiling points and vapor pressures of the two were the same at any given temperature . The fact that carbon tetrachloride boils at 76° C. while the boiling points of the hydrocarbons found in gasoline and naphtha may range from 37° , the boiling point of pentane ,

Nov 1, 1934

This chapter presents MSHA data on mine employment and active mining operations during 1986-1995. Figures 3-1 through 3-10 show, for each commodity, the location of mine operations in 1995, and employee hours and active mining operations by year during 1986-1995 for mine operators. For coal and nonmetal operators, the number of active mining operations and the number of employee hours decreased over the 10-year period. For metal operators, the number of active operations decreased, while the number of employee hours increased. For stone and sand and gravel operators, the number of active operations and the number of employee hours remained about the same. Figures 3-11 and 3-12 show that over the 10-year period, there was an increase in the proportion of hours worked by contractors in coal mining, while the overall employment decreased. For metal, nonmetal, stone, and sand and gravel combined, the proportion of contractor hours increased, with overall employment also increasing. Table 3-1 shows the distribution of hours worked during 1986-1995 by commodity and type of operation. For coal, the majority of hours worked were in underground mines. For metal, nonmetal, and stone, the largest number of hours worked were in mills and preparation plants. For sand and gravel, all work hours other than office were in surface mines. [ ]

Jan 5, 2000

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

MFIRE is useful for the analysis of ventilation networks under thermal and mechanical influence MFIRE simu¬lates a mine&apos;s ventilation system and its response to altered ventilation parameters, external influences, and internal influences Extensive output enables detailed quantitative analysis of the effects of the proposed alteration on the ventilation system MFIRE was written in FORTRAN 77 and compiled with Microsoft° FORTRAN for the Intel 8086-8088 central processing units The source code is listed in appendix A for users who wish to modify the source code for operation on other computers MFIRE MODIFICATIONS OF MTU-BOM CODE The program described in Bureau of Mines Informa¬tion Circular 8901 has become known as the MTU-BOM codes MFIRE is an evolutionary product of the MTU¬BOM code with major improvements and enhancements 6 For users previously familiar with the MTU-BOM code, the following is a listing of the major improvements and enhancements incorporated by MFIRE 1 The length of an airway is an input value, LA The elevation difference of the airway is calculated from the elevation input, Z, in both programs It is possible for a data file to describe an airway that is shorter than its el¬evation difference The MTU-BOM code does not check for this error and uses the values of LA and Z This does not cause a computational problem, only a simulation problem MFIRE issues a warning message for this case, and the airway length is made equal to the elevation dif¬ference if LA is less than Z 2 To evaluate rock temperatures (average wall surface temperature of airway before a fire), it is assumed that the air temperature at an airway entrance is equal to the air temperature at the airway starting junction, and that the air temperature at the airway exit is equal to the air tem¬perature at the exit junction. The MTU-BOM code follows this assumption in all cases When a rock temperature of less than 0° F is calculated, an average temperature is used to represent the rock temperature of the airway MFIRE uses the same principle, except the consideration of unlikely rock temperatures When the exit junction of an airway is the atmosphere (a fixed condition junction), the air tempera¬ture at the exit is made equal to the air temperature at the airway beginning If an unlikely value of wall temperature (<0° F or > 150° F) results from calculations, a message is issued and the rock temperature is set equal to the air temperature at the airway exit The program user can always input rock temperature (TROCK) for an airway to override the calculated value. 3 MFIRE allows use of an optional reference airflow rate to define and limit the heat generation of a fire source This allows the simulation model to more closely resemble a real fire and to improve simulation conver¬gence Heat generation corresponds, but is not linearly related to airflow rates reaching the fire In the simula¬tion, heat generation is calculated from oxygen consump¬tion and is directly related to the variable incoming airflow Use of this optional reference airflow rate allows the heat generation to vary, but in a damped, user defined manner When the airflow rate passing through a fire source is equal to its reference airflow rate, the data items describ¬ing the fire source are not modified If the airflow rate is lower or higher than its reference airflow rate, the data items used to define the fire source are modified according to the following equations

Jan 1, 1990

By Kathleen M. Kowalski, Audrey Podlesny

The Maslach Burnout Inventory (MBI) was administered and scored for 154 Mine Safety and Health Administration (MSHA) employees kom the US Department of Labor. These employees serve as accident investigators for serious accidents and fatalities as part of their job duties. During a workshop on stress designed for them, subjects volunteered anonymous written anecdotes, confirming and illustrating the findings. The subjects represented locations across the USA and all mining commodities: coal, metal, non-metal, stone, and sand and gravel. The Maslach Burnout Inventory assesses three aspects of experienced burnout: emotional exhaustion, depersonalisation, and reduced personal accomplishments. The average results of the scores for each of the three subscales for the study group of MSHA accident investigators fell in the moderate range. These scores show that the subject population was at some risk for emotional exhaustion and depersonalisation, tending toward burnout. The group evidenced a lower sense of personal accomplishment in their jobs, indicating a higher risk for burnout. From this outcome accident investigators may be at moderate (note: this does not mean average) risk for burnout. The authors recommend follow-up with this population - specifically in training to work with grieving families; and greater organisational support for the accident investigators in this area would be appropriate. Keywords: Burnout; accident investigators; occupational safety and health; job stress.

By F. D. Osgood, A. C. Fieldner, W. A. Selvig

In connection with investigations being conducted by the Bureau of Mines regarding pulmonary disease which is prevalent among metal miners in certain districts , a large number of rock- dust samples have been collected , and have been examined in the Bureau's laboratories . The earlier work has been described in Bureau of Mines Technical Paper 105 , " Pulmonary disease among miners in the Joplin district , Missouri , and its relation to rock dust in mines " by A. J. Lanza and Edwin Higgins , 1915 , and in Bureau of Mines Bulletin 132 , " Siliceous dust in relation to pulmonary disease among miners in the Joplin district , Missouri , " by Edwin Higgins , A.J. Lanza , F.B.Laney , and Geo . S. Rice , 1919. The methods of collecting and examining dust samples have been greatly improved during the investigation , much valuable information having been made available by similar investigations conducted by the Miners ! Phthisis Prevention Committee , Union of South Africa . The latter are described in the " General report of the Miners ' Phthisis Prevention Committee , Johannesburg, Union of South Africa , 1916 " , and " Final report of the Miners ' Phthisis Prevention Committee , Johannesburg, Union of South Africa , 1919. " The investigations by the Bureau of Mines and the South African committee show that by prolonged inhalation of air containing minute particles of sharp and insoluble rock dust , the lungs retain sufficient dust particles to cause decided injury to the lung tissue , the injured lung becoming very susceptible to the development of tuberculosis .

May 1, 1920