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By R. H. Sprute

The Bureau of Mines conducted a feasibility study and designed an operational system for consolidating waste coal sludge in a 110-acre pond by applying direct current between buried and floating electrodes. Consolidation would reduce the sludge to half its present volume, there-by extending the working life of the pond as well as creating a safe, stable impoundment. The project was conducted by the Bureau under an agreement with the Washington Irrigation and Development Co. (WIDCO), located near Centralia, WA. Part 1 of this report, published as Report of Investigation 8666 in 1982, covers the results of laboratory tests at the Bureau's Spokane Research Center and of a small-scale field test at WIDeO's coal preparation plant. Test results show the process is efficient and cost-effective when power is applied at low current density. Part 2 (this paper) describes a detailed design for an electrokinetic system to dewater WIDCO's 110-acre pond with a 27.4-acre electrode array. Densification of the inactive sludge pond will require 3.6 yr of treatment for a total cost of $1,450,000. The study and design are site specific, but design procedures and analyses are sufficiently detailed to serve as a guide for applying the process to any sludge pond.

Jan 1, 1988

By John P. Savage

This paper is one of a series being prepared by the United States Bureau of Mines on tunneling methods. The tunneling methods described are those used at the Ojuela unit of the Compania Minera de Penoles, S. A., the Mexican subsidiary of the American Metal Co., Ltd., of New York. The Ojuela unit is situated some 4 miles southeast of Mapimi, Durango. Mexico, the latter place being connected by a 15-mile narrow-gage railway with the standard gage railroad at Bermejillo, some 40 miles to the north of Torreon, the location of one of the company's smelters.

Jan 1, 1931

By J. J. Forbes

This publication is a revision of the first of a series of four Miners' Circulars originally prepared and issued in 19'29 for use in a course of training designed to prepare mine officials to organize men for rescue and recovery operations. These circulars were revised in 1937 and 1938 and again in 1948. This circular (Miners' Circular 33) discusses mine gases and methods for detecting them. The second of this series (Miners' Circular 34) gives instruction in Bureau of Mines methods of sampling and analysis of mine gases; the third (Miners' Circular 35) describes methods and equipment used for protection against mine gases; and the fourth (Miners' Circular 36) explains procedures used in sealing and unsealing mine fires and in recovery operations after mine fires or mine explosions.

Jan 1, 1954

By G. T. Krempasky

This report covers the installation and evaluation of lb reinforced concrete sets, 6 in each of 3 mines in the Goeur d'Alene mining district, Shoshone County, Idaho, and is the second of a series to determine the feasibility of a more permanent type of mine support. Closure measurements, where applicable, were made periodically of the concrete-set installations and were compared to the initial cross section of the sets. A different method of blocking was used at each test site; at one test site the type of blocking was changed several times during the test. Results from each test site are reported separately. No attempt was made to compare the cost of the concrete installations with the cost of other types of support used in the district. Such an evaluation of permanent types of support would require a longer period of time. At this time, tests are not complete enough to determine the applicability of underground concrete supports. However, results to date tend to confirm the general opinion that precast concrete mine supports could be used to advantage in openings that require support and must have long life, especially where decay of timber is an important factor.

Jan 1, 1963

By John E. Pahlman

The Bureau of Mines conducted column-leaching tests on 25 domestic Mn ores to determine the feasibility of extracting Mn by in situ or heap leaching with dissolved sulfur dioxide (S02) solutions. The ores tested were obtained from deposits in Arizona, Arkansas, California, Colorado. Maine, Minnesota, Nevada, and South Dakota. Dissolved S02 was found to be effective for leaching Mn; extractions greater than 90 pct were obtained with solution application rates of 1 mL/min from uncalcined, minus 2.5-plus 1.3-cm ore pieces. Leaching these ores with solutions containing only 5-wt-pct S02 and no added H2S04 resulted in Mn being selectively extracted over Fe except when Fe was present as goethite or siderite. Ca solubilization was inhibited by controlling the solution application rate (1 mL/min). The rate of leaching was found to be principally dependent upon the rate at which the leaching solution can penetrate the ore, since the solubilization of Mn upon contact with S02 was observed to be rapid. Despite low water permeabilities of the ores (as low as 10-2 to 10-4 darcy). greater than 90 pct of the Mn was extracted from even the largest ore pieces tested (approximately 10 cm in diameter). It appears, therefore. that leaching Mn opens up the pores, allowing penetration of the leach solution into the ore pieces.

Jan 1, 1988

By Wendell R. Peters

Shallow underground voids resulting from early coal mining and other resource recovery activities over the past several decades are now being recognized as a significant cause of ground subsidence problems in developing urban areas. Uncertain knowledge of abandoned coal mines also imposes potential hazards in coal excavation operations since water inundation or the release of methane gas is a pricnipal hazard when mine excavation operations break into an abandoned mine. U.S. Army requirements for an effective method for detecting and mapping subversive man-made tunnels have resulted in a surface-operated automatic earth resistivity survey system with a digital computer data processing system. Field tests aimed at demonstrating the system performance resulted in successful detection of tunnels having depth-to-diameter ratios up to 15 to 1. Under the sponsorship of the Bureau of Mines, a similar system was designed and constructed for use in the detection of coal mine workings. This report discusses the hardware and software aspects of the system and the application of the high-resolution earth resistivity method to the survey and mapping of abandoned coal mine workings. In the field tests reported, the targets of interest were both air-filled and water-filled workings.

Jan 1, 1980

An active list of permissible explosives was published in December 1936 as part of Bureau of Mines Report of Investigations 3324, under the title "Active List of Permissible Explosives and Blasting Devices Approved Prior to July 31, 1,936." This list included 170 brand names. Changes in the list that have been authorized to June 30, 1937 placed 35 additional brands of permissible explosives on the active permissible list as a result of tests, changes in brand names, or transfer from the inactive list. Ten permissible explosives were transferred from the active to the inactive list. The present list contains 196 brand names, one explosive having been placed on the list subsequent to June 30, 1937. The brand names of the permissible explosives placed on the active list are as follows: [ ]

Jan 1, 1937

Background: The National Institute for Occupational Safety and Health (NIOSH) recently investigated ignition incidents resulting from drilling holes into sealed and filled plow frame sections. A farmer and farm worker were seriously burned in two separate incidents that occurred in the same county in New York under similar conditions. They had just penetrated sealed sections of their plow frames with electric drills when a roar of escaping gas at high pressure was heard, and the victims were thrown back by the gas jet and engulfed in flames. The flames were quickly extinguished ,but the victims suffered burns. NIOSH experts were asked to help find the cause of these hazardous incidents.

Jun 1, 1998

By C. N. Rosenecker

The power required to circulate a gas-solids suspension was determined using a centrifugal compressor and a closed system. The suspension consisted of 18- to 40-micron glass beads in a mixture of 89 percent N2 and 11 percent CO2 at 20 psig. Solids-to-gas (S/G) ratios w re O to 2.2 lb/lb; gas flow rates were l.2 to 2.5 lb/min. Power requirement was found to follow the relationship hp t = hp(. + l), where hp t = the total power, and hpg = the power required for pure gas.

Jan 1, 1967

By M. J. Friedel, D. E. Scott, T. J. Williams

Rock masses in deep level mines are subject to high stresses, which can result in unexpected failure of rock into mined-out openings. Historically, various independent methods have been used to discern the causes of rock bursts and to evaluate stress conditions in rock masses susceptible to violent failure. Personnel from two research centers of the former U.S. Bureau of Mines, Spokane and Twin Cities, investigated a rock burst that occurred in May of 1994 in a rock mass between the 4400 and the 4600 levels of the Sunshine Mine, Kellogg, ID. The team evaluated the current state of stress in the pillar and the most likely cause of the rock burst by studying the seismic history of the pillar, examining the geology, analyzing the available in situ stress data, calculating possible fault-plane solutions for the burst, and performing a seismic velocity tomographic survey. The results of the study showed that post-rock-burst seismicity was concentrated about 15 to 30 m west of and about 15 m above the rock-burst location. The pillar is composed of a very hard sericitic-to- vitreous quartzite of a type rarely found in the mine, but that is often found in other district mines having a history of seismic activity. In situ stress analysis of the pillar and the surrounding rock mass showed a probable stress rotation from northwest-southeast to east-west. Of four fault plane solutions, the most probable was either a left-lateral, strike-slip movement with a compressive principal stress oriented nearly north-south, or a right-lateral, strike-slip movement oriented east-west. Finally, tomographic images showed low-velocity areas (interpreted as areas of low stress) associated with the crosscuts and haulageways, and high-velocity areas (interpreted as areas of high stress) associated with the rock-burst location. High velocities were also found in a planar area oriented in an elongate northeast-southwest direction.

By G. M. Potter, F. S. Wartman, M. D. Schmid

"In matte smelting of copper it has been established that the sulphpr present will combine with copper as long as the latter is present, and that thereafter it will combine with iron. The Cu-Fe ratio in the matte is determined by the Cu-S ratio, presumably owing to the much greater affinity of copper for sulphur or, expressed thermodynamically, the greater stability of copper sulphide in contact with silicate slag. Now, the work of Fournet and of Schütz, which is quoted in many elementary metallurgical texts, indicates that manganese ranks ahead of copper in its affinity for sulphur. Hence, we might expect that manganese could be concentrated from its admixture with iron. Compounds by matte smelting, and Rotts / has patented such a process. This greater affinity of manganese or sulphur is used to advantage in iron metallurgy, also, in which it is well-known that sulphur will combine with manganese and separate from metallic iron as manganese sulphide. Manganese sulphide,however, is quite soluble in silicate slags. 5/ The loss of manganese in slag in any attempted matte smelting is therefore great.If this solubility of manganese sulphide is slag is a physical one and the reaction MnO + FeS MnS + FeOIs substantially complete, then it might be expected that the addition of copper sulphide, which is almost entirety insoluble in slag, would serve to extract the manganese sulphide with the formation of a manganese-copper matte on the other hand, if an equilibrium exists in the above reaction, a copper sulphide layer would displace that equilibrium in one direction or the other, according to whether iron sulphide or manganese sulphide were more soluble in the matter layer."

May 1, 1937

By A. J. Rambosek

An evaluation of diamond-bit performance data accumulated from core drilling in quartzite shows that core recovery and physical characteristics of drill bits and diamonds have economic significance. Relatively inexpensive, low-quality, small Congo diamonds will perform as well as, or better than, other diamonds used as drill bart. M-type bits set with oriented Congo diamonds provide those engaged in core drilling with near optimum combination. Various factors that affect bit performance, including size of diamonds, size and type of bits, grade or quality of diamonds, and percentage of core recovered, are evaluated by means of tables, charts, and discussion.

Jan 1, 1958

By W. W. Weller

Low-temperature heat capacity measurements were conducted, and entropies at 298.15° K were evaluated for sodium monomolybdate (Na2Mo04), magnesium monomolybdate (MgMo04), and calcium monomolybdate (CaMo04). The 298.15° K entropy values were sodium monomolybdate, 38.1±0.3 cal/deg mole, magnesium monomolybdate, 28.4±0.2 cal/deg mole, and calcium monomolybdate, 29.3±0.2 cal/deg mole.

Jan 1, 1963

By Robert W. Freedman

The Bureau of Mines investigated methods of analysis of free silica in respirable dust, including both work done at the Bureau of Mines and work done elsewhere. The review covers both coal dust and noncoal dust, taking into account both existing and proposed chemical and spectroscopic procedures.

Jan 1, 1971

By N. S. Dalal, Xianglin Shi

"Electron spin resonance (ESR) spin trapping experiments have been carried out to investigate the mechanism of sulfite oxidation em¬ploying 5,5-dimethyl-l-pyrroline-1-oxide (DMPO) as a spin trap. The results show that sulfite autoxidation, catalyzed by Mn(II), involves not only the SO-3 radicals but also the •OH radicals. An addition of H2 02 to the sulfite aqueous medium significantly increases the •OH radical formation. This result provides new clues to the chemical mechanism of the sulfite oxidation and the sulfite toxicity.INTRODUCTIONStudies of the oxidation of the sulfite (SO 2-/3) ions under various conditions are of high current interest because excessive exposure to sulfite is toxic and the origin of this toxicity seems to involve sulfite oxidative pathways [1]. An important fact is that human exposure to sulfite is on the increase [1,2]. Some of the increase in the sulfite exposure is linked to the fact that SO2 is a major air pollutant [2] and in aqueous media SO2 exists in equilibrium with SO2-/3. In addition, beverages and foods are common sources of sulfite intake. For example, sulfite is used extensively in the wine industry as an inhibitor of yeasts and bacteria and is present in finished wines in concentrations up to 6 mM [1]. Sulfite is also often added to dehydrated fruits, vegetables and soups, as well as fruit juices and beer [1,3,4]. Because of these, the mean daily intake of sulfite from diet (in the United States) has been estimated to be between 0.0014 and 0.14 mM/kg body weight [1]. At such high levels, sulfite exposure can have toxic effects, such as the induction of an acute asthmatic state [5,6]. Sulfite also appears to have adverse genetic effects [7] and can act as a mutagen or comutagen [8] and a cocarcinogen [5,7-9]."

Jan 1, 1990

By Zsuzsanna Zborovszky

Experimental study directed toward gaining improved understanding of the exact mechanisms causing ignition in the PTB breakflash. Investigation and comparison of tungsten and copper wires as to their ability to cause hot wire ignition. Evaluation of the importance of discharge duration in the ignition process. Study of the parameters influencing the duration of a discharge (minimum discharge voltage, purity of electrode materials, purity and properties of the gaseous atmosphere contaminations, deposits on the electrode surface).

Jan 1, 1976

By P. D. Laverty

The U.S. Bureau of Mines treated mixed and contaminated super alloy scrap by pyrometallurgical and hydrometallurgical methods to separate and recover metal values. Best results were obtained by leaching Zn-treated or atomized scrap with HCI-02 at 9SO C and 50 psig 02' This resulted in dissolving approxi-mately 98 pet of the AI, Co, Cr, Cu, Fe, Mn, Ni, and Zn while rejecting over 98 pct of the Mo, Nb, Ta, Ti, W, and Zr as an insoluble refractory residue. Chlorine was successfully substituted for HCI to leach Zn-treated scrap but was unsuccessful for leaching atomized scrap. The leaching solution was treated by pH adjustment and hydrothermal precipitation at 2000 C for 4 h to remove AI, Cr, Fe, and other contaminants as a filterable precipitate. Recovery of Co and Ni would be accomplished by solvent extraction and e1ectrowinning. Chromium recovery as a ferroalloy was demonstrated.

Jan 1, 1989

By Charles L. Kimbell

In 1990, the aggregate value of world international export trade in mineral commodities was estimated at more than $64 billion in current (1990) dollars, about 8.4% higher than that in 1989, but still 8.7% below the record high set in 1980. Table 8 provides a data series for the estimated value of world export trade in all mineral commodities from 1979 through 1990, as well as a breakdown of this total into fuel and nonfuel commodities. It is noteworthy that for this 1990 edition, trade data for the year of review were available in time for inclusion, whereas in previous editions, the latest available global trade data were for the year prior to the year of review. Hence, as regards trade, this edition of Minerals in the World Economy updates the 1989 edition by 2 years rather than by only 1. For this reason, it is appropriate to note that the 1989 global total value for inter-national export trade in mineral commodities was almost $596 billion, 11.1 % above the revised 1988 level of more than $536 billion, both figures expressed in current dollars for the appropriate year. Despite the considerable increase in the dollar value of mineral commodity exports, their share of total export merchandise trade declined to 19.1 % in 1990 from 19.7% in 1989. At 19.1%, this share was very near the recent year record low of 19.0% reached in 1988. The year 1990 was the fourth in a row in which the total value of world mineral commodity export trade increased.

Jan 1, 1993

By P. J. Colbassani

Samples of mine atmospheres collected by Federal coal-mine inspectors during their inspections and investigations of coal mines, in accordance with provisions of the Federal Coal Mine Safety Act (66 Stat. 692; 30 U. S. C., sees. 451-483) are analyzed routinely by chemical methods at Bureau of Mines laboratories. When samples collected in open workings of nongassy coal mines at points not less than 12 inches from the roof, face, or rib contain 0.25 percent or more methane, the act requires the operator, during operation of such mine, to comply with the provisions of sec. 209, Title II, of the act, which pertain to gassy mines. The methane con-tents of such samples are determined by a physical method based on infrared absorption spectrometry to provide an independent check on analytical results obtained by chemical methods. This information circular describes the equipment and procedures used by the Bureau for determining low concentrations of methane in coal mine atmospheres by infrared absorption spectrometry. ACKNOWLEDGMENTS The authors are indebted to Dr. R. A. Friedel, Chief of Spectrometric Section, Branch of Coal-to-Oil Research, Bureau of Mines, for suggesting the analytical method and for furnishing valuable advice and assistance, and to J. A. Queiser of his staff for making exploratory measurements by this method; to Dr. M. G. Zabetakis of the Division of Explosives Technology for his assistance during the conduct of preliminary experimentation; and to L. B. Berger, Chief, Branch of Health Research, under whose guidance the equipment was procured and the work conducted.

Jan 1, 1958

By Matthew N. Rubin

This report summarizes the work performed under USBM Contract No. H0155155. The purpose of this work was to obtain operational data on retrofit noise control treatments suitable for use in coal preparation plants. This data was obtained by evaluating the performance of four categories of noise control treatments which were installed in a commercial coal preparation plant. The four categories of treatments were resilient screen decks, resilient impact pads, chute liners, and curtains. The selection, installation and initial evaluation of the treatments was documented in the Volume I report issued in 1977. This Volume II report summarizes the results of the long-term evaluation of the original treatments, as well as some additional tests which were conducted on elastomer-clad (resilient) screen decks. This project demonstrated the feasibility of a number of retrofit noise control treatments, some of which also proved to be quite durable over the long term.

Jan 1, 1982