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By John C. Edwards

The Bureau of Mines developed a mathematical model to predict the oxygen requirements for a miner evacuating a mine. The model accounts for variations in the miner's escape speed with mine airway height, and for the empirically determined expressions for the weight-specific oxygen uptake rate for upright walking, stooped walking (duck-walking), and crawling. A Fortran computer program that is user oriented was prepared based upon the model's constitutive equations. Specific instructions for utilizing the program, as well as applications to miner evacuation from a mine, are presented.

Jan 1, 1986

By J. H. Field

Synthesis of hydrocarbons by the Fischer-Tropsch reaction in a hot-gas- recycle system was demonstrated to be technically feasible. This project was undertaken, by the Bureau of Mines, to determine if the system was operable and to ascertain the optimum conditions for the production of gasoline. Carbon steel turnings packed with a void volume from 88 to 90 pct. were satisfactory catalysts, but steel catalysts with greater void volume, either turnings or steel wool, were not as active. Good temperature control with a pressure drop of less than 0.5 pounds per square inch (p.s,i,) per foot of catalyst bed of turnings was obtained by operating with a recycle to fresh feed ratio of 20 and by splitting the total gas flaw and injecting portions into the reactor at different entry ports.

Jan 1, 1961

By I. O. Salyer

This research was conducted with the objective of suppressing the respirable dust in coal mines by foam application. A formulation was developed for making a water-based, high-expansion, and limited stability foam. A horizontal boring machine was used as a laboratory coal mining model for generating coal dust. A modified laboratory foam generator was built. Foam was applied directly to the point at which dust was being formed by the cutter of the boring machine working against a block of coal. Coal dust was sampled with an impinger and analyzed for the particle count and particle size distribution. Coal dust suppression test results on freshly generated dust have demonstrated very clearly that in laboratory scale experiments over 90% of the respirable coal dust can be suppressed by foam. These tests were run when initial coal du t concentrations were 10 and 70 million particles per cubic foot (mppcf).

Jan 1, 1970

By A. F. Baker

Laboratory flotation of synthetic coal-pyrite mixtures and high-pyritic-sulfur coal indicated that ferric chloride (FeCl3), aluminum chloride (AIC13), chromium chloride (CrCl3), and cupric sulfate (CuSO4) are potential pyrite depressants. For each metal salt there appeared to be a range of pH values and optimum concentration for selectively depressing pyrite in coal flotation. Pyrite was depressed in the pH range from 4.5 to 7.0 with ferric chloride, from 5.8 to 7.0 with aluminum chloride, from 6.4 to 7.1 with chromium chloride, and from 6.4 to 7.4 with cupric sulfate. Best separation of pyrite from coal was achieved in flotation solutions containing from 2 X 10-5 to 5 x 10-5 mole/ liter of each salt. In solutions containing excess salt concentrations, coal was also depressed. These Bureau of Mines tests demonstrated on a laboratory scale that, in solutions containing 4 X 10-5 mole/liter ferric chloride and from 1 x 10-4 to 2 x 10-4 mole/liter sodium hydroxide, the pyritic sulfur content of a Lower Freeport bed coal sample could be reduced from about 2.51 percent to less than 0.60 percent with recoveries of over 83 percent. The depression of pyrite appears to be due to the adsorption of positively charged colloidal metal hydroxide at the pyrite-solution interface. This hypothesis is supported by zeta potential determinations which showed that suspended coal and pyrite particles in solutions containing metal salts are positively charged in the pH range where depression occurs.

Jan 1, 1971

By H. F. MILLE, Charles A. Kumke

This paper describes mining operations at the Iron King mine of the Shattuck -Denn Mining Corp. in Yavapai County , Ariz . It is one of a series being prepared by the Mining Division of the Bureau of Mines on mining practices and methods in various mining districts of the United States . The mine and surface plant of the Iron King mine are situated in secs . 15 and 21 , T. 13 N. , R. 1 E. , about 20 miles by State highway 69 east by southeast from the city of Prescott and 1 mile southwest of the mining town of Humboldt on the Prescott -Mayer branch of the Atchison , Topeka & Santa Fe Railroad (fig . 1 ) . A l-mile truck haul brings the mill concentrates (lead and zinc ) to bins on a siding of this line at Humboldt ; the silver -gold bullion is handled separately . Some of the oldest residents in the vicinity of Prescott claim that the original location for the Iron King mine was made in 1880. The earliest recorded production was in 1906-1907 . During the first World War the mine produced fluxing ore for the Humboldt smelter . In 1936 the property was purchased under tax sale , and a mill (140-ton capacity ) was erected in 1938. The capacity of this mill was increased to 225 tons the following year , and a cyanide plant was added in 1940 to treat mill tailings . In 1942 the Shattuck -Denn Mining Corp. purchased the property . A new working shaft was sunk , mine development was speeded , and mill capacity was again increased . The predominating locally formation of this district is a pre -Cambrian schist known as Yavapai schist . The Iron King deposit , which carries gold, silver , lead , zinc , and copper , occurs as a series of lenses in a sheared zone of the pre -Cambrian schist . Down to the 600 -foot level the ore was mined and drawn by the shrinkage method . The cut -and -fill method was adopted for the lower levels . Waste rock for stope fill was provided by block-caving an area on the 600 level . Main haulage drifts were driven in the firm footwall , and crosscuts were driven across the mineralized zone at 100 -foot intervals . Grab samples taken from each car of every working place and channel samples cut every 5 feet in development work are considered sufficient for estimating ore reserves .

Jan 1, 1950

By David J. Kusler

This report describes a primary or direct, continuously sampling, and automatically averaging gravimetric method for analyzing gaseous mixtures of carbon dioxide, carbon monoxide) hydrogen, and (by volume measurement) nitrogen. The gaseous mixture is analyzed by passing it at a controlled and definite rate through a system that permits carbon dioxide and water retained by appropriate absorbents to be determined and the residual-gas volume (essentially nitrogen) to be measured. The accuracy and dependability have been established by comparison with very carefully conducted Orsat analyses. The method was developed for, and has been satisfactorily applied to, the analysis of blast-furnace top gas. It permits relatively attention free operation, using simple and low-cost materials usually found as basic equipment in the analytical laboratory. It provides, over a wide range of time or sampling intervals (from less than 1 to over 24 hours), the average composition, in terms of volume-percent, for those components usually determined in blast-furnace gas, if (as is usual) the flow rate of gas from the blast furnace is essentially constant over a selected analysis interval. Oxygen and methane are not determined; but, since these gases are normally absent or present only in traces, their analysis is seldom required.

Jan 1, 1959

By J. C. Barrett

Bureau of Mines research on the arc welding characteristics of titanium was initiated in 1948. Little was known about the art except that the easily contaminated metal required more protection from the atmosphere during welding than most other metals. Chambers were designed and built within which titanium could be welded with adequate inert gas protection. Welds were made and their properties studied, and prototype items were made successfully. This report, presenting a resume of the titanium arc-welding experiments undertaken by the Bureau of Mines, demonstrates that the process is successful if conducted under proper conditions and describes the welding of prototypes. INTRODUCTION The Bureau of Mines' first report on methods of joining titanium covered the subject of spot welding,4/ outlining the conditions necessary for producing spot welds in ductile titanium consolidated by powder metallurgy methods and describing the characteristics of such welds. This report embraces the field of fusion weld-ing of titanium and traces the development of suitable methods and equipment for producing such welds.

Jan 1, 1956

By Harold E. Marr

Energy dispersion X-ray analysis was evaluated for possible application in the secondary metals industries for the rapid analysis and identification of copper-base alloys. Laboratory investigations of standard brass and bronze samples indicate that X-ray methods are capable of separating standard alloys into 10 general classes with analytical times of less than 3 seconds per sample for clean, flat samples. A radioactive source of americium 241 with a secondary fluorescer was used as an excitation source, and a lithium-drifted silicon semiconductor detector was utilized for energy discrimination of X-rays.

Jan 1, 1974

By A. Visnapuu

The Bureau of Mines, as a part of its goal to minimize occupational hazards associated with mining and mineral processing operations, has developed and field tested a compact exhaust air muffler for mechanized, jumbo-mounted pneumatic rock drills. The muffler is constructed of 1/8-inch sheet steel and has nominal dimensions of 1-3/4 by 9 by 13 inches. A directed air passage, flexible neoprene baffles, and an expandable slit-type outlet are incorporated to reduce drill exhaust air noise and eliminate muffler icing. Field tests in actual mining operations showed a l5-dbA reduction in exhaust noise and an 8-to 12-dbA reduction in overall drilling noise with no icing problems or decrease in drill performance. Data are presented on muffler construction, laboratory, and field test results.

Jan 1, 1979

By Arne Landsberg

A study of the chlorination kinetics of germanium, silicon, iron, tungsten, molybdenum, columbium, and tantalum has been made to determine the effects of temperature, chlorine concentration, geometric surface area and gamma radiation. The reaction products were volatile at the temperatures used this making it possible to follow the reaction rates by weight loss of the solid. Chlorination rates of germanium, silicon, and iron were found to be directly proportional to chlorine concentration while the rates for tungsten, molybdenum, columbium, and tantalum were proportional to the 0.5 to 0.6 power of chlorine concentration. A good correlation of reaction rate and geometric surface areas was not obtained because the true surface area of the samples could not be measured. Intense gamma radiation had no effect on reaction rates. The Arrhenius activation energies determined over the temperatures used are as follows: Germanium, 27 kcal/mole (233°-241° C); silicon 33 kcaL/mole (375°-517° C); iron, cold rolled, 20 kcal/mGle (259°-325° C) annealed, 21 kcal/mole (293°-337° C); tungsten, 43 kcal/mole (617-776° C); molybdenum, 37 kcal/mole (445°-4910 C); columbium) 34 kcal/mole (229°?255° C); and tantalum, 29 kcal/mole (370°-449° C).

Jan 1, 1965

By Jeffrey A. Aldinger

This U.S. Bureau of Mines report presents an analysis of surface coal mining accidents involving mobile equipment for the years 1989 through 1991. Mobile equipment is defined as haulage trucks, front-end loaders, bulldozers, scrapers, and road graders. These five pieces of mining equipment accounted for 20 pct of all surface coal mine accidents and 41 pct of the fatalities. The general discussion of these accidents covers the accident causes, the primary activity of the accident victims, and other contributing factors. A more detailed analysis of accidents associated with each piece of mobile equipment is also provided. This report will provide mine managers and mine safety personnel with a better understanding of the hazards associated with mobile mining equipment. It identifies where improvements in mobile equipment safety can be made and those areas requiring additional safety emphasis, such as safety training, work procedure changes, or engineering changes to the equipment or work environment. The analysis was performed by a team of researchers using accident data and narratives provided by the Mine Safety and Health Administration.

Jan 1, 1995

By W. G. Messner

Pipelines for transporting crude oil and refined products in the United States totaled 189,982 miles on January 1, 1959. This mileage was less than a 1-percent increase from the 1956 total of 188,540 miles. During the three-year period (January 1956 - January 199), 14,886 miles of new pipe and 10,649 miles of secondhand pipe was laid. Pipe taken up in the same period was 24,093 miles. The facts regarding pipeline mileage were obtained by the Bureau of Mines from pipeline companies and information provided by the Interstate Commerce Commission. Crude-oil gathering lines, as of January 1959, were 40 percent of the United States pipeline mileage and totaled 75,182 miles, an increase of 1,656 miles during the three-year period. Crude-oil trunklines totaled 70,317 miles or 37 percent of the United States pipeline mileage, a decline of 8,277 miles from the 1956 total. Some of this loss is attributed to the converting of crude lines to refined products. Refined product lines in January 1959, totaled 44,483 or 23 percent of the United States mileage, an increase of 8,063 miles during the three-year period.

Jan 1, 1959

By John C. Machisak

The thirty-fifth consecutive National Safety Competition sponsored and conducted annually by the Federal Bureau of Mines, Department of the Interior, closed with several noteworthy accomplishments to its credit. Some of them are: 1. A record low injury-frequency rate of 18.293 disabling work injuries per million man-hours equal to that established in 1957. 2. The third lowest injury-severity rate (4,335). 3. The second highest number of mines and quarries participating (672) 4. A record number of participants finishing the competitive year without a disabling work injury. 5. All recipients of Sentinels of Safety trophies free of disabling work injuries for the first time since 1952.

Jan 1, 1961

By Ann G. Kim

Acid drainage from underground coal mines and coal refuse piles is one of the most persistent industrial pollution problems in the United States: This Bureau of Mines report reviews the acid mine drainage problem generally and describes research currently underway to combat it.

Jan 1, 1982

By R. D. Van Zant

The method for smelting zinc in horizontal retorts developed several centuries ago is still in use. This process consists essentially of the reduction of zinc oxide by carbon at 1,200° to 1,400° C. in a fire-clay retort. The reaction is highly endothermic, and a high radiation loss occurs in transferring the heat of reaction through the fire-clay walls. In recent years, silicon carbide retorts with much better heat-transfer characteristics than fire clay have been supplanting the old retorts. The practical impossibility of recovering the carbon monoxide formed in the reduction causes a large loss of fuel. Intermittent smelting is done in small retorts that are manually charged and discharged, and the furnace crews must be specially trained if efficient results are to be obtained. During the past 20 years several processes have been introduced that have substantially improved the horizontal-retort process. One of these, developed by the New Jersey Zinc Co., consists of a continuous process in which a briquetted mixture of zinc sinter, reducing agent, and binder is coked at 750° to 900° C. and charged into a vertical silicon carbide retort. A supply of displacement air or exhaust combustion gas is introduced at the base of the retort at an appropriate pressure in order to keep the zinc vapor from condensing on the cooled residue in the lower part of the retort. Any .oxidizing constituents in the displacement gas are converted to carbon monoxide by reaction with the carbon in the charge. The spent residue is continuously removed at the bottom of tl1e retort. The chief advantages of this process are said to be increased output per man-day, improved working conditions, high recovery of zinc, increased thermal efficiency, and long retort life.

Jan 1, 1950

By T. A. Lang

The objective was to develop a Program Plan of analytical studies and tests for determining (1) the optimum installation tension of a coal mine roof bolt, (2) the most valid bolt support theory or theories, and (3) the most valid roof failure theory or theories. On this basis a comprehensive literature search was made and significant material dealing with coal mine roof behavior, roof bolting and roof support was collected, reviewed, classified and analyzed. Emphasis was given to the influence of rock reinforcement on the control of deformation, stress field modification and mine roof stability. An assessment was made of the effect of various parameters including bolt tension, bolt pattern and time of installation, on the effectiveness of rock reinforcement systems, and equations developed for bolt tension as a function of these parameters, and rock properties. From these studies, a major program plan of tests and studies was developed for verifying and validating the most tenable theories of roof behavior and roof support and for determining optimum bolt installation tension.

Jan 1, 1979

By Pamela J. Watson

The U.S. Bureau of Mines has demonstrated in laboratory tests that drilling with surface-charge-neutralizing concentrations of polyethylene oxide (PEO) polymer solutions simultaneously improves penetration rates and extends bit life. The applicability of this additive to improve drilling performance in coal measure rocks was demonstrated under field conditions at an abandoned mine land site in Pennsylvania and a producing coal mine property in Ohio. Penetration rate improvements ranging from 15 to 50 pet were obtained when core drilling through a variety of coal measure lithologies. Drilling cost analysis indicates that the small added cost of using the polymer is more than offset by the savings that result from demonstrated increased drilling penetration rates, which translate into drilling cost savings of about 10 to 30 pct. This report also gives chemical analyses of a variety of coal measure rocks and some corresponding local drilling water samples, obtained from a wide geographical base, along with threshold concentrations of PEO required to effect the improved drilling performance in these rocks. From these data, the threshold PEO concentrations needed to ensure improved drilling performance can be estimated for any coal measure rock suite. Proper techniques for mixing PEO solutions are also presented.

Jan 1, 2010

By Homer J. Ballinger

During the fall of 1943 and spring of 1944, the Bureau of Mines investigated nine secondary limonite iron-ore deposits in the Williamsville district of Wayne, Butler, and Ripley counties, Mo., by rotary-bucket and power-auger drilling test pitting, and trenching. Studies on beneficiating the ores were made at Bureau laboratories. Iron ore has been mined in Missouri since 1825, and iron mining reached its greatest development between 1870 and 1890. During this period, production averaged about 250,000 tons annually.

Jan 1, 1948

By Michael G. Zabetakis, Aldo L. Furno, Henry E. Perlee

The Bureau of Mines conducted an experimental study with liquid and gaseous hydrogen to determine the hazards associated with the use of liquid hydrogen as an ionizing particle detector in bubble chambers . The glass window , the vacuum chamber , and the vent system were investigated . In addition , a study was made of the detection and ignition of escaping hydrogen and of the available electrical equipment for use in hydrogen atmospheres . Materials such as tempered glass , aluminum , and stainless steel are not penetrated readily by the small fragments formed when fully tempered glass is shattered and propelled by hydrogen at initial pressures up to 100 psig ; long , slender fragments from untempered glass may penetrate thin walls of relatively soft materials such as rubber gaskets and lead . Hydrogen can be vented satisfactorily from a vacuum chamber with a well - designed vent system . However , the rapid leakage of hydrogen into the surrounding air is a serious problem because the available detectors are satisfactory only when the accumulation of hydrogen is slow . Much of the electrical equipment currently available was designed for use in hydrogen- air atmospheres .

Jan 1, 1963

Exposure to airborne respirable crystalline silica dust can lead to silicosis, a debilitating lung disease. On surface coal mining and construction sites, blast hole drills are notorious sources of airborne respirable dust that may contain significant amounts of silica. The drill operator and drill helper usually receive the greatest silica exposure compared with other occupations. As a result, many drilling operations have been, and still are, on more stringent dust standards. Drilling through various rock formations naturally presents a strong potential for silica dust generation for several reasons. First, drilling is a pulverizing process that generates large amounts of very small dust particles. Second, the bailing air used to flush cuttings from the hole leaves the hole at a very high velocity and can be difficult to contain. Third, many fixed shrouds used to enclose the area beneath the drill deck have a significant amount of leakage due to 1) gaps between the shroud and ground created by raising/leveling the drill, 2) gaps in the corner seams, and 3) tom deck shrouds. CONTROLS A dry dust collection system is typically connected to the drill deck to collect dust as the bailing airflow transports the cuttings (and significant amounts of airborne respirable dust) out of the drill hole. Deck shrouds are installed in an attempt to enclose the volume around the drill steel and prevent dust escaping. However, most deck shrouds are rectangular and constructed of four separate pieces of rubber belting attached to the deck. Because of this design, there is usually a significant amount of dust escaping from the open seams as well as the open area between the shroud and the ground. This dust can be a significant source of silica exposure to drill operators as well as other personnel downwind of the drill.