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By P. M. Brown

The Bureau of Mines is investigating a dewatering technique for coal-clay waste that uses a flocculant, polyethylene oxide (PEO). This flocculant forms strong stable flocs that can be dewatered on a static screen. A field test unit (FTU) using this technique was operated at approximately 400 gal/min, using a waste stream from the flotation circuit of a coal preparation plant. Consolidated coal-clay material con-taining 55 to 60 pct solids was produced when the flotation circuit slurries of 2.7 to 8 pct solids were treated with 0.1 to 0.3 Ib PEO per ton of solids. The FTU was also operated at 64.5 and 87.5 gal/min using a portion of the underflow slurry from the preparation plant's thickener. Consolidated coal-clay material containing 55 to 60 pct solids was produced when the thickener underflow slurries of 19 to 24 pct solids were treated with 0.08 to 0.2 Ib PEO per ton of solids. PED-treated materials continued to dewater when placed in a pit.

Jan 1, 1983

By G. R. Hopkins

According to reports received by the United States Bureau of Mines, Department of Commerce, as of January 1, 1929, there were 2,205 cracking units completed or being built in the United States, with a total daily charging capacity of 1,476,874 barrels. A similar survey of a year ago showed 2,334 units of 1,288,000 barrels total capacity. This indicates that despite a decrease in. number of units, there was a material increase in capacity. The year 1928 was, in general, an important one for the cracking branch of the industry. Gasoline consumption reached record levels, prices were higher than in 1927, and it is probable that in the late months of the year the cracking plants were operating very close to capacity.

Jan 1, 1929

By G. W. Birge

As a part of its overall program of coal carbonization, the Bureau of Mines is studying the coking properties of coals that may be used for metallurgical purposes. The objectives of this study were given in detail in a previous report.2/ The inherent suitability of coal for metallurgical use depends primarily on (1) chemical composition, (2) preparation characteristics, and (3) carbonization behavior. The first two factors, as well as the available reserves, are considered in selecting coals for carbonization tests. The selection of coal beds in Westmoreland County for coking tests was based, in part, on estimates of the coal reserves by Dowd,3/ who estimated the recoverable reserves in beds 28 inches or more thick, in thousands of tons, as follows: [ ]

Jan 1, 1957

By Edward D. Thimons

As U.S. mines go to greater depths, the high temperatures and humidities characteristic of such depths make it difficult to maintain a comfortable environment in working areas. Better techniques for cooling these deep working areas are needed. At the Homestake gold mine in South Dakota the Bureau of Mines has tested a water spray cooler inserted into the fresh air vent tube entering a warm stope. The cooler supplied more than 6 tons of refrigeration to the stope air, which dropped from an inlet temperature of 83° F dry bulb and 75° F wet bulb to 73.5° F dry bulb and 71.5° F wet bulb. These preliminary results show the water spray cooler to be a feasible concept. However, there is a need for substantial refinement and further testing, and work on the concept will be continued under contract to the Bureau.

Jan 1, 1979

By Dennis R. Dolinar, Lewis A. Martin

Cable bolt technology used by the U.S. coal industry was developed to a large extent in the 1990s. Today, these cable systems include both cable bolts and cable trusses to provide supplemental and secondary support in gate roads. This cable technology is significantly different than the cable systems in use in either U.S. hard-rock mines or Australian coal mines. Development of this technology was initiated and spurred by research efforts of the U.S. Bureau of Mines, and has continued under the health and safety programs of the National Institute for Occupational Safety and Health (NIOSH). It was also followed up by work of roof support manufacturers to create an essentially new support system. In this paper, the important support characteristics of both cable bolts and cable trusses are discussed. The design of cable systems and the basis for that design for tailgate and headgate situations are reviewed and explained. Case histories are presented on the application of these support systems based on experience gained at a number of in situ test sites.

Jan 10, 2000

By J. M. Mutmansky, R. A. Jankowski, M. A. K. Mohamed

"SYNOPSISKnown health hazards associated with the breathing of respirable dusts, particularly silica dust, during mining are becoming a great concern in many parts of the world. The search for effective and low cost dust control methods for underdeveloped countries will help in improving the productivity and keeping the mine environment safe. This article addresses the problem by providing suggestions concerning the easiest and most cost effective methods to control respirable dust in mining and mineral processing operations. INTRODUCTIONMedical BackgroundLung diseases caused by dust in mining operations have been recognized by mankind since the time of the Roman Empire. The writings of Pliny the Younger on natural history reported on maladies associated with dust in mining in the first century AD. However, no significant advances in controlling the lung diseases of miners came about for many centuries. The effects of mineral dusts were further described by Georgius Agricola in his sixteenth century book on mining (Agricola, 1556). After the appearance of Agricola""s book, lung diseases were more readily recognized, but the nature and severity of the ailments associated with mineral dusts could not be readily interpreted.In 1896, the discovery of x-rays by Roentgen advanced the diagnosis of lung diseases and the knowledge of what causes these diseases. In addition, the discovery allowed medical personnel some method of judging the extent and severity of the lung diseases in human beings. During the ensuing years, the term 'pneumoconiosis' became the common term to describe any of the diseases of the lung in which dust particles deposited in the lungs caused fibrous tissue and loss of some of the respiratory function. However, little in the way of social remedies for the diseases resulted until much later. Society was still not ready to act decisively to reduce the causes of lung disease due to the dusty conditions in the work place.Social action against lung diseases did not occur in the United States (US) until the 1930s. At that time, a tunnel driven through a sandstone mountain near Gauley Bridge. West Virginia, caused the death of several hundred workers due to acute silicosis, a severe form of pneumoconiosis caused by silica (Seaton, 1975). Dust conditions in this tunnel were quite bad, causing many of the workers to be subjected to extremely high silica dust concentrations. The severity of the disease in many of the workers became known to the public and prompted the US Congress and many of the states to enact laws to reduce the dust levels."

Jan 1, 1998

By Donna D. Harbuck

The Bureau of Mines has investigated a process to produce titanium powder directly from titanium salts. If successful, such a process could lower the cost and increase the use of titanium. In this study, K2TiF6, K2TiF3, and TiF3 were reduced with potassium in the temperature range of 650° to 750° C. Under certain conditions, titanium powder 1.6 to 3.3 microns in size was produced. After leaching the product with a 0.1M HCl solution, powder impurities as low as 0.04 pct potassium and 0.28 pct fluorine were obtained. However, oxygen levels of over 1 pct and the frequent formation of insoluble byproducts demonstrate the need for further research to make the powder suitable for powder metallurgy applications.

Jan 1, 2011

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

5. Development of Initial Probing System 5. 1 Introduction The preliminary evaluation of a variety of potential methods for initial probing showed that the optical system using closed circuit television (CCTV) and the sonar, or acoustic ranging, system were the most promising. The former is capable of pro¬viding a visual display of the mine passages in a clear, non-smoky environment, and the latter is capable of providing a map of the spatial location of the coal surfaces making up the entries, as well as objects, such as cribs, mining machines, etc., in the passages in both smoky and non-smoky environments. The sonar system used in conjunction with the CCTV in a clear environment can greatly assist in resolving the spatial distribution of objects seen on the TV screen. Further, in a smoky environment the interpretation of the sonar information could be facilitated if some visual information were also available. CCTV systems exist but require some modifications to suit this particular application. The Industrial Hazards and Communications Division of the Bureau has an ongoing program for the development of such a CCTV system. Rather than duplicate this effort in developing a CCTV system, it was decided to evaluate the possibility of utilizing their system for initial probing, while continuing with the develop¬ment of a system which would work in any environment, including the presence of dense smoke. The concept of using sonar for the initial probing of mine passages represents the application of new technology requiring development. The results of such a development effort undertaken during the course of this program are described in the following sections.

Jan 1, 1973

By J. H. Hild

The Shanton magnetite-ilmenite deposits lie on the east flank of the Laramie Mountains, 43 miles northeast of Laramie, Albany County, Wyo. (fig. 1). The Shanton and other similar deposits in the Laramie Mountains were examined by Bureau of Mines engineers during 1942, 1943, and 1945, and a report2/ describing the results of a dip-needle survey and surface sampling was published in 1946. The Shanton deposits occur in a relatively flat section of the range at altitudes varying from 7,500 to 1,650 feet (fig. la). Prevailing rocks in the Shanton area consist of anorthosite with intrusive dikes of gabbro differentiates and granite. Titaniferous magnetite outcrops in five masses, which are separated at the surface by overburden and anorthosite.

Jan 1, 1953

By Herbert R. Babitzke

The purpose of this investigation was to optimize the high-temperature properties of columbium and tantalum. Columbium and tantalum were combined with selected alloying elements to achieve solid solution and dispersion strengthening. Fifty-six alloys were evaluated to determine their formability, hardness, strength at elevated temperatures, and oxidation resistance. The following six alloys showed high-temperature strength: [Cb-15Hf-5W-2Zr-4Al-4Ti-2N Cb-15Hf -5W-5Zr Cb-15.3Ti-4.1Zr-13.7Hf Ta-20Hf-4Al Ta-30Hf-4Al Ta-20Hf-5W-4Al] At 1,200° C, the columbium alloys had strength values of 40,000 psi or greater, and the tantalum alloys had strength values from 50,000 to 58,000 psi. For a 2-hour test period at 1,000° C, weight gains of only 9 and 8 mg/cm2, respectively, were observed on oxidation testing of two alloys, Cb-15Hf-5W-2Zr-4Al-4Ti-2N and Ta-20Hf-5W-4Al.

Jan 1, 1968

By Eric R. Bauer

This U.S. Bureau of Mines study was conducted to gain a basis for recommending methods to predict and prevent the occurrence of cutter roof failure, a common ground control problem in mines of the Northern Appalachian Coal Basin. This was accomplished by determining the geologic and engineering factors responsible for cutter development at six mines affected by cutter roof failure. Three distinct factors were found to be initiators of cutter roof failure: (1) high horizontal roof stress, (2) surface topographic variations, and (3) geologic anomalies. Effective control of cutter roof was obtained through improved bolting techniques, entry and mine reorientation, and entry and pillar size modifications, but only when selected based on the actual cause of failure.

Jan 1, 1990

By E. R. Cole

Bench-scale research at the Bureau of Mines has resulted in the successful development of a combination electrorefining-electrowinning method for recycling all the lead in scrap batteries. The method reduces energy consumption and eliminates toxic emissions, in contrast to present pyrometallurgical smelting, and the lead produced is pure enough for use in maintenance-free batteries. Anodes cast from molten lead scrap were electrorefined in 1-and 2-liter plastic cells using an electrolyte composition of 70 g/l Pb and 90 g/l free H2SiF6 (fluosilicic acid). Both reagent-grade and waste H2SiF6 were used. Cathode starting sheets were made from refined lead. Aloes, and later bone gelatin, and calcium lignin sulfonate addition agents were employed. The sludge remaining after separation of the lead metal was treated in a two-step leaching operation to solubilize the lead for recovery by electrowinning. Conditions for electrowinning were essentially the same as for electro-refining, except that insoluble Pb02-Ti (lead dioxide-coated titanium) anodes were used. The best results for both electrorefining and electrowinning were obtained with a current density of 170 amp/m2 and a cell temperature of 25° to 35° C. Cathode purity ranged from about 99.9 to 99.99+ pct Pb. Maximum energy consumption after 3 days, for electrorefining and electrowinning, was 90 and 700 kwhr per metric ton of refined lead, respectively.

Jan 1, 1981

By Charles L. Kimbell

In overview, 1988 appeared to be the best year for the world's mineral industry since 1980, although the all-important petroleum component suffered severely from low prices. With this notable exception, the traditional statistical measures of mineral industry performance, namely production, trade, and consumption, reflected growth in most elements of the world mineral industry from crude material extraction through the gamut of downstream processing. Moreover, the growth was reasonably well distributed geographically, with many countries sharing in the substantial upturn in activity. World crude mineral output value was estimated at over $1,272 billion in current dollars ($1,090 billion in constant 1983 dollars). The value added by the processing component of the mineral industry raised the total value of the industry's output to an estimated $3,057 billion in current dollars ($2,620 billion in constant 1983 dollars). Less easily assessed was the value of mineral commodities moving in 1988's international world trade, particularly because of the declines in world crude oil and refinery product prices. It remained to be seen if increased volume and value in nonfuel mineral and coal exports, coupled with an increase in the volume of oil exports, would be adequate to offset the drop in oil prices. Whether or not the value of world mineral commodity trade topped the 1987 level of over $498 billion, an increase in the volume of mineral commodity trade was almost assured. Similarly, although comprehensive statistics were not avail-able on consumption of all mineral commodities in all countries, available data on selected major commodities in selected major countries suggested that not only had output of most mineral commodities advanced, but so too had consumption levels for most commodities.

Jan 1, 1990

By S. J. Pearce

There are a number of methods for determining relatively small quantities of sulfur dioxide in air. However, those methods require fairly elaborate apparatus and laboratory facilities. Frequently in industrial hygiene surveys it is desirable to have a simple arrangement to obtain "on the spot" determinations. This has been accomplished for concentrations of sulfur dioxide of hygienic significance by using the midget impinger and decolorizing a starch-iodine solution.

Jan 1, 1948

By L. B. Pankratz

High-temperature heat contents were measured for two praseodymium oxides and three terbium oxides. There were: Pr2O3 (298° to 1,600° K), PrO1.833 (298° to 1,050° K), Tb2O3 (298° to 1,600° K), TbO1.719 (298° to 880° K), and TbO1.812 (298° to 850° K). With the exception of PrOl.833, all results were regular. PrO1.833 had a small thermal anomaly at 760° K with an extra absorption of 380 cal/mole. The measured heat content values, tabulated smooth heat contents, and entropy increments are reported. Heat content equations were derived.

Jan 1, 1966

By G. W. Jones

The operation of combustion engines of various types at high altitudes and other combustion processes at reduced pressures have made it desirable to determine limits of flammabilities -under these conditions. Experiments carried out by the Bureau of Mines have shown that although natural gas-air mixtures become more difficult to ignite as the pressure is reduced below atmospheric, with a suitable source of ignition the limits of flammability are as wide at 175 mm mercury absolute as they are at atmospheric pressure.

Jan 1, 1949

By C. J. Chindgren

A refractory-lined, garage-type automobile incinerator with a natural gas afterburner for air pollution control was cooperatively constructed and tested by the Bureau of Mines and the Wasatch Metal & Salvage Co. in Salt Lake City, Utah. The incinerator is capable of relatively smokeless burning of 32 to 60 cars per day, dependent on the degree to which the cars are stripped prior to incineration. Preliminary burning campaigns indicate the cost of incineration to be approximately $2.75 per car.

Jan 1, 1970

By J. E. Tiffany

Some of the gases produced by permissible explosives on detonation are poisonous, and the probable hazard involved by the inhalation of carbon monoxide in the past has been evaluated from results of tests in the Bichel Gage. Tests have now been made in the Experimental Coal Mine of the Bureau of Mines at Bruceton, Pa., to determine the composition of the gases obtained under actual mining conditions for the purpose of comparing these, results with those found by the Bichel gage tests. Two permissible explosives were procured for these tests, one that produces a relatively low quantity of poisonous gases in the Bichel gage (24.8 liters per 1-1/2 pounds of explosive) and another that produces a relatively high quantity of poisonous gases (94.6 liters per 1-1/2 pounds). The first of these is designated by the Bureau of Mines as a class A4/ explosive and the other is designated a class B explosive. In comparison with Bichel-gage tests, the shooting of permissible explosives in a coal shot hole resulted in a large reduction in the quantity of carbon monoxide, the principal poisonous gas, which; in the mine tests, was only 22 percent of that found in Bichel-gage tests: The quantity of carbon monoxide from the class B explosive in Bichel-gage tests was 3.8 times larger than that from the class A explosive; in the coalmine tests the ratio was 4:1. The concentrations of carbon monoxide in the mine tests, as determined by analysis of the atmosphere in an enclosed space resulting from shooting 1-1/2-pound and 3-pound charges of the class A explosive, were 0.03 and 0.06 percent, respectively, and the concentrations from 1-1/2-pound and 3-pound charges of the class B explosive were 0.10 and 0.24 percent.

Jan 1, 1950

By B. J. Dalton

The Helium Research Center, Helium Activity, Bureau of Mines, is presently engaged in a critical examination of all of the PVT data on helium that appear in the literature. The long-range objective is the development of a single equation of state for helium that will allow all of the thermodynamic properties to be calculated and will reproduce all of the data within the accuracy with which the data are known. A preliminary objective is to obtain the best values of the second virial coefficients and to develop an equation that will reproduce the best values as a function of temperature. The method of treatment consists in expressing the PV product of a gas, for a given isotherm, in terms of a power series in either the pressure or the density and evaluating the constants by least squares solution. Associated with these functions whose coefficients have been evaluated by least squares, the following errors, or deviations, are of interest; the standard error of a single measurement; the standard error in each coefficient; and the standard error of the resulting function.

Jan 1, 1964

By B. J. Dalton

The Helium Research Center, Helium Activity, Bureau of Mines, is presently engaged in a critical examination of all of the PVT data on helium that appear in the literature. The long-range objective is the development of a single equation of state for helium that will allow all of the thermodynamic properties to be calculated and will reproduce all of the data within the accuracy with which the data arc known. A preliminary objective is to obtain the best val¬ues of the second virial coefficients and to develop an equation that will reproduce the best values as a function of temperature. The method of treatment consists in expressing the PV product of a gas, for a given isotherm, in terms of a power series in either the pressure or the density and evaluating the constants by least squares solution. Associated with these functions whose coefficients have been evaluated by least squares, the following errors, or deviations, are of interest; the standard error of a single measurement; the standard error in each coefficient; and the standard error of the resulting function.

Jan 1, 1964