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By P. M. Sullivan

This report describes a new application of electroamalgam metallurgy in recovering all the zinc as refined metal from galvanizers' sal skimmings. Pure zinc was recovered by electrolysis of skimmings leach liquors in amalgam cells. The following information was gained as a result of literature studies and subsequent laboratory investigations. 1. Reports in the literature indicate that pure zinc can be recovered from chloride solutions with the aid of amalgam cells. From Europe it was reported that amalgam cells could be used to recover pure zinc and chlorine from leach liquor obtained from pyrite cinders following a chloridizing roast.

Jan 1, 1956

By Oliver Bowles

This report covers the character, properties, origin, occurrence, and uses of the traprocks and describes briefly the methods and equipment employed in quarrying and preparing them for market. Production of traprock occupies an important place in industry. In 1960 the output in the form of crushed stone reached nearly 58 million tons valued at $87 million. Traprocks are also shaped into blocks of dimension stone for monuments, building construction and decoration, and specialized products such as surface plates.

Jan 1, 1963

By Oliver Bowles

This report covers the character, properties, origin, occurrence, and uses of the traprocks and describes briefly the methods and equipment employed in quarrying and preparing them for market. Production of traprock occupies an important place in industry. In 1960 the output in the form of crushed stone reached nearly 58 million tons valued at $87 million. Traprocks are also shaped into blocks of dimension stone for monuments, building construction and decoration, and specialized products such as surface plates.

Jan 1, 1963

By Joseph A. DeCarlo

For the first time the Bureau of Mines is combining, in one report, comprehensive tabulations on both beehive and slot-type ovens. This publication presents statistical data on the number and capacity of all such coke ovens in the United States on December 31, 1957. Combining data on both types of ovens should prove helpful to those interested in keeping abreast of the latest changes in carbonizing capacity, particularly since the coke has similar properties and uses. Annual reports furnished to the Bureau of Mines by coke-oven operators shared that 78 oven-coke plants were operating in 22 States on December 31, 1957. This was a decline of one plant from December 31, 1956, as the Republic Steel Corp. took the ovens at Canton, Ohio, out of production on December 17, 1957, for dismantling and rebuilding in 1958. Total oven-coke capacity was 80,299,400 tons in 1957.

Jan 1, 1958

By J. E. Tiffany

"The new permissible blasting device, Cardox, utilizes as a blasting agent liquid carbon dioxide which is discharged.as a gas from a steel container or shell. The loaded shell is placed in a borehole, stemmed, and tamped in a manner similar to that employed with explosives, and is fired by electricity.The Bureau of Mines' approval for use of the device in coal mines was granted as Approval No. 1 under date of October 3, 1928; as the result of tests made under the conditions and requirements of Schedule 20. There have been three subsequent extensions whereby minor modifications in the original design were granted.The permissibility of the device is subject to the following conditions; (1) It shall be in all respects similar to the sample submitted for tests; (2) certain thicknesses of disc and. weights of heater ingredient and of carbon dioxide, all of which are set forth in Table 2 under the provisions governing permissibility, must be used: (3) the rear cap must always be in place after the shell has been charged, to prevent accidental firing; and (4) firing must be done by means of a permissible-type blasting unit.The permissibility of Cardox was established by gallery tests similar to those used in testing explosives for permissibility. In these tests the shell was discharged into gallery 1 without causing any ignition of gas and air or of gas, dust, and air mixtures there. The conditions of charging the shell, such as weight of the ingredients of the heater element, the carbon dioxide charge, and thicknesses of the disc, were varied according to the conditions under which it would be likely to be used in blasting. The tests made in gallery 1 are here described in detail, as are also the tests which have been made for determining the propulsive strength of the device and the quantities of poisonous gases given off when a shell is discharged."

Mar 1, 1929

By J. B. Ligon

Blast induced stress waves, propagating along the surface of a drift of an underground hardrock mine, were recorded and analyzed. Resistance strain gages, accelerometers and a velocity pickup were used in making the measurements. Although a full face blast was recorded, the stress waves were initiated by single borehole blasts for the majority of the project. A special instrument trailer was designed, constructed and utilized during the project. A reliable strain wave transducer was developed for measuring the stress waves propagating on the drift surface. A correlation study between strain and acceleration signals for P-waves was made which agreed well with theory. The use of stemming was found to reduce strain and acceleration magnitudes as predicted.

Jan 1, 2011

To provide longwall operators with a method to predict methane emissions from panels with increased face width.

Jan 1, 1997

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 Frank E. Cash

"INTRODUCTION The producing iron-ore ranges in the Lake Superior district are the Marquette and Menominee in Michigan, the Gogebic in Michigan and Wisconsin, and the Cuyuna, Mesabi, and Vermilion in Minnesota. These ranges produce about 85 percent of the iron ore mined in the United States. The accident experience in connection with this production is better than that of the regions producing the remaining 15 percent. Production and shipments vary slightly from year to year owing to stockpiling underground ore during the winter, or nonshipping, season but closely approximate each other over a period of years. This information circular supplements, combines, and continues the data contained in Information Circulars 7321 3/ and 7410 4/, including statistics for 1946 and 1947.Whereas the title ""Accident Experience"" is used for uniformity and logical indexing throughout this report, ""injury"" will be used as a general term to apply to disabilities of all degrees.During the 8-year period 1940 to 1947, inclusive, 619,054,023 long tons of iron ore was shipped from the Lake Superior district. 5/ Michigan and Wisconsin shipped 117,828,939 tons, or 19.03 percent of the total, and employed approximately 9,260 men. Minnesota shipped 501,225,084 tons, or 80.97 percent of the total, and employed an approximate annual average of 12,260 men. The tons produced and shipped per man employed in Minnesota is much greater than in Michigan and Wisconsin, owing to the large open-cut production in Minnesota."

Jun 1, 1949

By D. B. Dow

"Natural gas-gasoline is made by collecting in the liquid state the condensable hydrocarbon vapors that exist in different natural gases in varying amounts. In the richer type of natural gas the gasoline is generally recovered by compression and cooling. If exceedingly high pressure or low temperature is used, there is dissolved in the gasoline a large amount of very volatile material, which evaporates rapidly at atmospheric temperature and pressure.In the leaner type of natural gas, the gasoline vapors are selectively absorbed from the permanent gases by passing the natural gas through an absorbing oil. The gasoline is recovered by distilling the saturated oil, and as compared with ""compression"" gasoline is of high Baume' gravity and low vapor pressure. Before a volatile gasoline can be transported in tank cars, it is necessary to decrease its volatility in order to lessen the risk of fire or explosion, as well as to prevent excessive evaporation in transit. This can be accomplished either by weathering the gasoline, or by blending it with a more stable material, naphtha being commonly used in the weathering process the more volatile portions of the gasoline are allowed to evaporate and the losses in volume are very large, therefore, blending is preferable, wherever possible.It is very difficult, however, to produce by blending, in gasoline plants, a motor fuel which is equal to straight-run refinery gasoline. In order to make a blended motor fuel of a grade equal to straight-run gasoline, only a small percentage of natural gas-gasoline can be blended with the naphtha, consequently it is customary to blend the gasoline with only enough naphtha to enable It to be shipped to an oil refinery when the material is again blended to form a finished motor fuel."

Sep 1, 1921

By M. Hertzberg

This Bureau of Mines report proposes a new methodology for estimating industrial dust explosion hazards in terms of three probabilities or co-factors: The dispersion of the dust, the existence of a flammable dust concentration, and the presence of an effective source of ignition. This method or rationale is proposed as a replacement for the "explosibility index" that was first suggested 25 yr ago, but which, by consen-sus among leading researchers in the field, is now outdated. This report presents a detailed critique of the deficiencies of that old, material-oriented index, and develops the logical rationale for its re-placement by an approach that is better suited for quantitative hazard evaluations. A variety of such evaluations are illustrated, which show how a quantitative prediction of explosion frequencies can be obtained from laboratory measurements and operating conditions in a given indus-trial facility. The method has some pitfalls, particularly as they re-late to the correlation of events or their randomness. These are discussed, as well as the method's other limitations and uncertainties. This work is intended to provide a beginning to a quantitative approach to explosion hazard assessment. To that end, a new method is proposed for estimating thermal ignition probabilities in terms of the measured laboratory autoignition temperature of a dust, its relationship to the operating temperature, and its distribution within a given industrial system.

Jan 1, 1987

By John D. Sullivan

The recovery of copper by leaching from relatively low grade ores containing both oxidized and sulphide minerals is rapidly gaining in commercial importance. There is an economic limit below which certain ores can not be treated by concentration methods, and material with values below this limit must be discarded, possibly to be treated later, or the copper must be extracted by wet processes. Heap leaching has been carried out by the Phelps Dodge Corporation, Copper Queen Branch, for several years, and to-day its plant is a large producing unit. The Ohio Copper Coy at Bingham, Utah; has been leaching in place since 1919. Many other leaching operations are also being; carried out in various parts of the United States and in foreign countries. The plant at Rio Tinto, Spain, may be considered the father of heap leaching.

Jan 1, 1931

By R. V. Ramani

"The importance of adequate mine ventilation for good health and safety conditions has been recognized since miners first ventured underground. All over the world, governmental actions on mine health and safety arc directly connected with mine atmospheric environments their assessment and control. These governmental actions have been, and continue to be, motivated by the repeated experience that potential threats from inadequate control can evolve, either suddenly or in the long-term, into unpleasant reality, with catastrophic health and safety consequences. These governmental actions arc also an indication of the remarkable professional progress being made in the field of mine ventilation.Surely, no developed country allows underground mines to operate without strong measures for the control of ventilation under legislation specific to the mining industry. In the United States, the federal government's responsibility for mine safety has evolved over the years through a series of legislative actions beginning in 1865 and continuing through 1910, 1941, 1947 and 1952.The passage of the Federal Metal and Nonmetallic Mine Safety Act of 1966 (the 1966 Metal Act), the Federal Coal Mine Health and Safety Act of 1969 (the 1969 Coal Act) and the Federal Mine Safety and Health Amendments Act of 1977 (the 1977 Mine Act) arc the most important milestones in this long legislative history. The 1977 Mine Act adopted many of the stronger features of the Occupational Health and Safety Act of 1970, perhaps the most significant piece of legislation on workers' occupational health and safety in US history.It is worthwhile to ask, ""How far has the United States come in mine ventilation since the enactment of the 1969 Coal Mine Health and Safety Act?"" This Act and its associated regulations defined in great specificity many standards for healthful and safe operation of a mine and. in some cases, what constitutes good ventilation practice."

Nov 1, 1995

By A. E. Back

A method has been developed in the laboratory for successfully treating titaniferous magnetite ore from the deposit at Iron Mountain, Wyo. The ore is roasted with 15 percent sodium carbonate to convert the vanadium to a water-soluble form and fix the soda for the subsequent electric-smelting step. Approximately 90 percent of the vanadium is recoverable in a product assaying 80 percent V2O5. The leached calcine is briquetted and smelted in a graphite-lined electric-arc furnace. Substantially all of the titanium is recovered in a soda slag, assaying 60 percent TiO2 and 2 percent Fe, which can be upgraded to 75 to 80 percent TiO2 by leaching with dilute sulfuric acid. The upgraded slag could be utilized for the production of titanium dioxide pigments or titanium tetrachloride. About 90 percent of the iron is recovered as pig iron, containing only minor amounts of vanadium, titanium, and sulfur. The high TiO2 slag compares favorably with slag containing about 70 percent TiO2 being produced by the Quebec Iron & Titanium Corp. at Sorel, Quebec. The data obtained from this investigation indicate that a feasible process has been developed for treating Iron Mountain ore, and larger-scale testing is warranted to develop engineering data for the ultimate utilization of this deposit as a source of titanium, iron, and vanadium. There are adequate supplies of basic raw materials, electric power, water, sodium carbonate, coal, and petroleum products within fairly short distances of Cheyenne and Laramie, Wyo., the nearest cities and probable plant- and labor-supply points.

Jan 1, 1952

Provide better ventilation for mines by reducing air leakage around stoppings. Approach Most stoppings are constructed of concrete blocks and trowelled-on mortar and are not very airtight. Bureau of Mines research has shown that brushing on modified mortar containing fiberglass and/or other additives, that enhance strength and adhesion, minimizes air leakage around and through the stoppings. Airtightness is an important factor in building stoppings since an airtight stopping will provide for more efficient ventilation airflow and more cost-efficient use of the mine's ventilation system. How the New Technique Works After broken floor and rib material is removed, the stop-ping faces are covered with one or two coats of modified

Jan 1, 1982

By M. R. Geer

All the coal lands in Alaska are publicly owned, and the Federal Government is the principal consumer of coal. Therefore the Government has long been concerned with the wise utilization of the coal reserves of Alaska as well as with the availability of coals meeting the specifications for use in various Government installations. Coal preparation plays a key role in both of these areas of interest. The proper choice and operation of coal-washing equipment permits the mining of inferior deposits, minimizes waste of coal in preparation, and assures a prepared product of the best quality obtainable from the raw coal. Thus, from time to time, the Bureau of Mines has made washability examinations on most of the coals mined in Alaska. Generally, these examinations were made when new mines or new beds were opened, when construction of new preparation plants was being considered, or when the operation of existing plants could be improved by better knowledge of the raw coal. The purpose of this report is to bring together all the washability data available on the coals of the Matanuska Valley and Beluga River fields. The pattern of energy development for the rapidly growing Anchorage area is not clear at this time. Formerly coal was the only fuel available for large-scale space heating and power generation. More recently both oil and natural gas have entered the market, and several hydroelectric projects have been completed. Additional major hydroelectric projects are being considered. The role that will be played by coal in this competitive energy market is uncertain. However I if coal is the fuel used in future power plants or industrial installations, the information contained in this report will be useful in indicating the quality of the coals that can be supplied and in selecting proper preparation techniques.

Jan 1, 1962

By Mary A. Barrett

The Bureau of Mines conducted a laboratory-scale investigation of grouting mixtures containing iron or aluminum to determine the existence of health or explosion hazards, due respectively to oxygen depletion or hydrogen emission. Mixtures containing iron created an oxygen deficiency in less than 24 hours and released small amounts of hydrogen; a health hazard could occur but only under extremely unfavorable conditions. Mixtures containing aluminum released little hydrogen and consumed little oxygen; however, if improper on-site mixing yielded high local metallic aluminum concentrations, enough hydrogen might be released to produce an explosive atmosphere in a confined space.

Jan 1, 1969

By V. F. Parry, W. S. Landers

"INTRODUCTION The primary object of this investigation was to determine changes in physical and chemical properties of subbituminous lump coal while in storage for 8 months in a typical residence and to demonstrate how this fuel may be stored without degradation or spontaneous combustion. The second object of the study was to determine how the stored coal performed in a hand-fired furnace operated under practical conditions.The investigation revealed that if care is exercised in placing sub-bituminous lump coal in a closed bin, no significant slacking or degrada¬tion occurs, no hazards arise, and over-all indicated efficiencies of about 65 to 69 percent can be obtained under practical,firing conditions that the average home owner can meet.Owing to the war emergency, much attention is being given to the proper storage of coal, and campaigns are being conducted to increase the quantity of coal being stored to relieve transportation and production overloads. Ordinarily, coal dealers do not recommend storage of subbituminous coal in homes owing to deterioration of the coal and to possible hazards from spontaneous combustion. This practice has grown from some troubles that have been experienced, which can be traced to improper preparation, improper bins, and poor technique in placing coal in a bin. There is no good reason why subbiturninous lump coal cannot be stored safely in homes."

Jun 1, 1944

By James W. Ballard

The facts are generally accepted that an atmosphere containing large quantities of any dust is objectionable to breathe and that some dusts are more dangerous than others. Therefore, knowledge of the composition of dusts is important in evaluating the hazard entailed on exposure. At present, free silica, of which quartz is the most abundant form, is considered one of the most significant dusts, from the standpoint of pneumoconiosis, and one State5/ has established permissible limits of air dustiness on the basis of the free-silica content of rock. The amount of free silica in materials used for rock dusting also has been limited.6/ Determination of free silica or quartz, therefore, is important.

Jan 1, 1940

By N. C. Tomoeda, W. D. Bensema, J. W. Adams

Measurements of surface magnetic field noise were made at various locations over the Geneva Coal Mine near Price, Utah, on June 12, 1973. The locations selected were on the surface over emergency locator beacons underground at depths between 350 meters (1150 ft .) and 488 meters (1600 ft .) . The surface terrain where these measurements were made was mountainous, and access was difficult. There were no power lines within several miles, and the weather was clear; therefore, the magnetic noise levels were about as low as will normally occur. Results of measurements of distant sferics indicate rather sharp cutoff frequencies below which broad- band, impulsive noise is attenuated. The mechanism of propagation for this noise above the daytime cutoff frequency of 3500 Hz and the nighttime cutoff frequency of 1700 Hz is deduced to be a waveguide formed by the D or E layers of ionosphere as an upper plane and the earth as a lower plane. The measurement systems used are similar to those used earlier. The technique is to record broadband, analog signals, digitize the data, and use a fast- Fourier transform to obtain spectral plots. This tech- nique is novel in that it can measure simultaneously all magnetic field energy within a limited portion of the spectrum for a limited time, and, after processing, reproduce the events occurring in that time interval in great detail .

Jan 6, 1974