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By Yun-tao Xin, Yu Yi, Kang Yan, Gang Li, Xiao-dong Lv

This study investigated the selective removal of arsenic from high-arsenic dust in alkaline systems and the effects of different leaching conditions. The results indicated that the liquid–solid ratio, NaOH concentration, and sulfur dosage had a significant influence on the process. The leaching efficiency of arsenic reached 99.57%, while that of lead was as low as 0.03% under appropriate conditions. In particular, the addition of sulfur can effectively promote the leaching of arsenic and reduce the dissolution of lead in the solutions. An artificial neural network was used to model the leaching process. It consisted of a back-propagation artificial neural network model with a “6–10–2” structure that could effectively simulate and predict the value with more than 99% accuracy. Based on the difference in weights of the different parameters in the neural network model, the relative importance of the parameters related to arsenic and lead leaching efficiency was obtained, which followed the order of NaOH concentration, liquid–solid ratio, sulfur dosage, temperature, time, and stirring speed.

Jul 29, 2021

By C. P. Bowie, George L. Gates

"INTRODUCTION Experience in drilling oil and gas wells has shown that the voidance of blow-outs, twist-offs, fishing jobs, loss of circulation, and heaving and caving of shale formations into the drill hole depends largely on how well the drilling-mud fluid serves its purpose. A possible method for the control of the drilling fluids may be seen from a study of the relation between the particle-size distribution and some of the important drilling-fluid properties, such as the ability to build quickly a relatively impervious mud sheath on the wall of the hole in the porous formations penetrated by the bit during drilling operations. In a wartime economy, which urgently requires conservation of steel, proper functioning of the drilling fluid is particularly important because, as Parks 4/ has stated, intelligent use of good drilling fluids makes possible drilling of wells for thousands of feet in open holes without the necessity of setting protective strings of casing to control the movement of salt water, gas, and troublesome formations into the borehole; consequently, especially in deep wells, of proper drilling fluids materially reduces the need for casing and lowers the cost of drilling and completing the wells."

May 1, 1942

By Carl R. Peterson

The Rapidex continuous spiral blast tunneling concept uses a spiral blast pattern that provides efficient slabbing action, continuous progression, and partial self-shielding. A lightly shielded tunneling machine using this concept stays at the face to provide continuous drill, load, shoot, and muck functions. Previous phases proved the effectiveness of the blast pattern in the White Pine Shale tested the design features of the shield and developed a remote loading and shooting capability using inductively initiated blasting caps and a pumpable slurry explosive. Phase IV assembled previously used front-end elements (drill, loading components, shield) on a used Joy loader chassis and added a mucking system television monitoring and remote control elements. Remote television monitored loading shooting and mucking were investigated. Difficulty was experienced in locating previously drilled blastholes near the bottom of the heading and even on the face. These holes often had to be considered as lost. Because of hydraulic system deficiencies and overall congestion of machine elements at the face mucking rates obtainable with remote television monitoring were low (on the order of 16 tons per hour). Performance was good enough to indicate improved rates if more space were available and if extreme thoroughness were not required. Because of the serious nature of the lost hole problem, a new explosive loading scheme was given a preliminary evaluation. The new scheme would require the explosive and the detonating charge to be loaded through the drill steel. If the necessary equipment modifications could he made and if safe, efficient operation were assured, the new scheme would alleviate some of the crowding at the face and would eliminate the lost hole problem.

Jan 1, 1978

By C. S. Allbright

This report gives the results of analyzing three groups of crude shale oils by the Bureau of Mines procedure:4/ (1) Oils produced by standard Fischer assay determinations on oil shales from Brazil (Paraiba Valley) and the United States (Colorado); (2) oils produced from Brazilian shale by different retorting methods; and (3) oils from high-temperature retorting of Colorado oil shale in the Entrained Solids retort. It is the second in a series presenting data obtained by analyzing crude shale oils from various sources. The series furnishes information on the general characteristics and compositions of a wide variety of shale oils. Use of a standard analytical method on all samples facilitates comparison of different oils. The 18 oil samples analyzed in this project comprised 3 from assays of Brazilian and Colorado oil shales in the Fischer retort, 9 obtained by processing Brazilian shale in various other units, and 6 from entrained solids retorting of Colorado shale at 1,000° to 1,500° F. The crude oils from Brazilian shale contained about half as much nitrogen as the Colorado oils. Properties of the Fischer assay oils from Colorado shales agreed with some data that relate grade of the oil shale with properties of the crude oil from the Fischer assay. Comparison of results from Fischer assays of oils from the foreign and domestic shales shows that the oil from Brazilian shale contains more low-boiling material and less residuum than either of the two from Colorado shale. This fact is reflected in lower specific gravity, viscosity, and carbon-residue values for the Brazilian oil. Retorting Brazilian shale in the Entrained Solids unit at 1,120° F. produced an oil whose boiling range was generally lower than the boiling ranges of oils obtained by processing in three other retorts at conventional temperatures. The quality of crude oils from high-temperature retorting of Colorado shale in the Entrained Solids process varies with retorting temperature. As the temperature is raised within the range 1,000° to 1,500° F., the amount of the naphtha fraction in the crude oil increases to about 35 percent and the aromaticity to 98 percent.

Jan 1, 1956

By Scott W. Hazen

This report describes the design, analysis, and results of a special experimental mine-sampling project conducted as part of the Bureau of Mines continuing program on sample-methods research. The experimental project was conducted at the Bureau?s Denver Mining Research Center and at the Climax molybdenum mine within the framework of a cooperative research agreement between the Bureau and Climax Molybdenum Co., Division of American Metals-Climax, Inc. The primary objective of the project was to investigate the interrelation-ship between sample volume, number of samples, the standard deviation of an assay distribution, and the precision required for an estimate of grade of ore, and to develop this interrelationship into a relatively simple method of application for use in mine sampling.

Jan 1, 1962

By Jeffrey M. Listak, Gregory J. Chekan

The U. S. Bureau of Mines is investigating longwall panel layouts to maximize coal recovery and minimize interactive problems in multiple-seam operations. When coalbeds are longwall mined in descending order, the transfer of stress from overlying gate roads is a major design constraint affecting pillar stability in the lower mine. The lower mine gate road pillars must be properly designed to withstand the additional load transfer if gate roads are superpositioned in successive seams. The Bureau's MULSIM/NL model, a boundary element computer program, was used to analyze load transfer mechanics for superpositioned gate road pillars. Analysis of Longwall Pillar Stability (ALPS), an empirically based design method for longwall gate road pillars, was used to calibrate model input parameters. ALPS provided a basis to verify model trends and to recommend limits for safe pillar design when superpositioning longwall gate roads. The attributes of the MULSIM/NL model and ALPS were combined to develop a modified method for estimating pillar stress for multiple-seam cases. The modified method uses a multiple-seam factor (MS) to estimate the stress on superpositioned lower mine gate road pillars. Numerical analysis shows that MS depends on the interburden thickness and pillar width.

Jan 1, 1992

By P. K. N. Raghavan

This paper identifies potential technologies for Carbon dioxide abatement from the mining and metal industry with special reference to the Aluminium industry. Mine reclamation could contribute to this effort to successfully reach the greenhouse gas (GHG) emissions reduction commitments for a nation. An overview of GHG production by the mining and metal industry together with a review of principles used to set the context in which specific options for GHG reduction are described. Options for GHG reduction in the mining and metal industry include reforestation, Addition of soil amendments or neutralizing agents, CO2 capture and storage, initiatives towards energy reduction, waste heat recovery and alternative energy use. An analysis and quantification of the potential GHG reduction of potential carbon sinks and sequestration options for the mining and metal industry are provided. Cost estimates for different options are provided. The paper also identifies sources that could fund research regarding GHG reduction options. The paper concludes with recommendations.

Jan 1, 2011

By E. P. Barret

Differences in the reducibility of iron oxide materials have been recognized for a long time. Limonites are deoxidized more readily than hematites, and unaltered magnetites are the most difficult to deoxidize. Sinters are found between hematites and magnetites and vary considerably in reducibility, depending on the sintering practice followed and on the degree of fusion of the product. The increased activity in the beneficiation of taconite recently has made available a new blast-furnace raw material, namely, iron oxide pellets made from magnetic taconite concentrate. Many of the data in this paper apply to these pellets, or glomerules, as they were called when this method of agglomerating iron ores was first considered. To clarify the terms applied to iron oxide materials in this paper, the following definitions are given. Agglomeration is the general term applied to all methods of compacting or consolidating fine iron oxide materials. Sinter is the product from a Dwight-Lloyd or Greenawalt sintering machine. Pellets are formed by balling fine, moist oxide in a rotating drum at room temperature, followed by heating in a shaft furnace to a temperature below that of incipient fusion to develop a permanent bond. Nodules are formed by heating the iron oxide material to incipient fusion in a rotary kiln. Briquets are formed in a mold under pressure, with or without the addition of a binder, and burned to develop a permanent bond.

Jan 1, 1949

By Humberto García Uculmana

El presente texto es un análisis realizado en la corporation Centromin de Cerro de Pasco que señala las características del material pirítico y su asociación con la plata. El estudio a través de diversas pruebas de laboratorio determina los esquemas semi-industriales económicos para la recuperación de plata y otros valores a partir de los minerales refractarios. En este sentido, Centromin dispone de tecnología para beneficiar esta fuente convencional primaria de plata, donde utiliza el proceso de lixiviación ácido clorurante en pilas para producir aproximadamente 500 mil onzas de plata a un costo menos operativo.

Nov 24, 1986

By A. L. Engel

[Thi;. re:9ort presents re3ults of investigations of problema a3signed as ore-testing projects to the Ore-Dressing Section, t.fetal1urgica.l Div:biion, of the Bureau of Ii.fines at the .fississippi?Valley E>"'1lcrimcnt Station in rtolla, Ho., durine the fiscal year ended June 30, 1940.]

Jan 1, 1941

By O. S. North

As recently as the late 1920's there Were few indications that a 15-million-dollar-a-year industry would ever grow out of the mineralogic curiosity vermiculite. Today, it is an important industrial commodity, used primarily as an insulating material and lightweight aggregate, but with a wide range of other applications. The quantity of crude vermiculite produced and used in the United States increased 14-fold in the 17 years between 1935 and 1951. The vermiculite minerals are of secondary origin, formed by hydrothermal alteration of an ultrabasic igneous rock, generally pyroxenite, or by alteration of phlogopite or biotite mica or possibly other similar minerals. According to different authorities, vermiculite may originate either by direct hydrothermel means, by the weathering of biotite or phlogopite, or by a combination of these two agencies. Vermiculites frequently occur at or near the contacts of an acid intrusive rock, especially a pegmatite dike, with a basic or ultrabasic country rock.

Jan 1, 1953

By Harry E. Krumlauf

The year 1957 was one of declining metal price and production. Many lead-zinc-copper mines were forced to close, and the remaining mines limited production to stay more in line with demand. High cost of labor, supplies, and equipment and high taxes aggravated the situation. Some operators postponed or abandoned expansion programs because of uncertain economic conditions. Output was curtailed by elimination of over- time employment and reduction of the working force. The number of employes laid off was small- reduction in the labor force was accomplished by not replacing those who left a company's employ.

Jan 2, 1958

By S. V. Rungan

The modern mining industry is increasingly being tasked to comply with various legal, industry and social prerequisites. In addition to complying with these, the mining industry is further expected to effectively report on their compliance. Although there are many models that aid the mining industry in compliance and reporting, it is perhaps opportune for a new model to be introduced. The Compliance Spindle is postulated as a new and alternative model which is easy to understand and has the possibility of implementation in South Africa and other jurisdictions as well. The Compliance Spindle is also an effective tool to educate future compliance officers. The new model provides for all aspects of compliance and reporting and can be easily modified to take account of new developments in the mining compliance and reporting arena.

Jan 1, 2010

By Merwin H. Howes

Gnome shaft, situated about 24 miles southeast of Carlsbad, N. Mex., was designed and sunk by the U.S. Atomic Energy Commission for conducting a peace- time experimental nuclear explosion in the thick salt beds of the Permian Salado formation. Excavation was started July 1, 1960, and completed July 26, 1961. The 10-foot diameter shaft, lined with concrete through the rock section, was sunk 1,216 feet. A drift was driven approximately 1,140 feet on the 1,200- foot level terminating in a shot chamber. On completion of 100 feet of shaft, by means of a truck-mounted crane, facilities were installed for conventional sinking. About 709 feet of rock and 506 feet of salt were encountered in the shaft. Salt beds at this place are reported to be over 1,200 feet thick. The overlying rock section varies greatly in composition and thickness of beds and contains a 28-foot bed of water-bearing dolomite. The aquifer was sealed to facilitate shaft sinking and to prevent water-seepage damage in the salt section of the shaft. Sealing was accomplished by grout injection through holes drilled into the aquifer and by grouting behind the concrete liner.

Jan 1, 1963

By Merwin H. Howes

Gnome shaft, situated about 24 miles southeast of Carlsbad, N. Mex., was designed and sunk by the U.S. Atomic Energy Commission for conducting a peace-time experimental nuclear explosion in the thick salt beds of the Permian Salado formation. Excavation was started July 1, 1960, and completed July 26, 1961. The 10-foot diameter shaft, lined with concrete through the rock section, was sunk 1,216 feet. A drift was driven approximately 1,140 feet on the 1,200-foot level terminating in a shot chamber. On completion of 100 feet of shaft, by means of a truck-mounted crane, facilities were installed for conventional sinking. About 709 feet of rock and 506 feet of salt were encountered in the shaft. Salt beds at this place are reported to be over 1,200 feet thick. The overlying rock section varies greatly in composition and thickness of beds and contains a 28-foot bed of water-bearing dolomite. The aquifer was sealed to facilitate shaft sinking and to prevent water-seepage damage in the salt section of the shaft. Sealing was accomplished by grout injection through holes drilled into the aquifer and by grouting behind the concrete liner.

Jan 1, 1963

By Hamed Khodadadi, Hamid Ghadiri

In this study, a fuzzy logic self-tuning PID controller based on an improved disturbance observer is designed for control of the ball mill grinding circuit. The ball mill grinding circuit has vast applications in the mining, metallurgy, chemistry, pharmacy, and research laboratories; however, this system has some challenges. The grinding circuit is a multivariable system in which the high interaction between loops, the variation of the system parameters with time, and time delay are some of the problems that pose a challenge. Since the controller parameters are determined offline in classic PID control, these gains are unchangeable and cannot overcome the mentioned challenges in this system. Hence, a fuzzy logic self-tuning PID controller, which is a combination of fuzzy logic and a conventional PID controller, is proposed to control the grinding system, especially in the presence of model mismatch and disturbances. In addition, in order to solve the system challenges, a multivariable control approach based on an improved disturbance observer is proposed to suppress the effects of the disturbances. The most important feature of the algorithm proposed in this paper as the combination of fuzzy logic self-tuning PID and improved disturbance observer is its ability to eliminate system interaction, attenuate internal and external disturbances, and compensate the effect of system uncertainty on the performance of the ball mill grinding circuit. Simulation results in the cases of the set-point change in particle size and circulating load in the presence of model mismatch and external disturbances confirmed the controller performance compared to other controllers.

By A. L. Engel

[This report presents results of investigations of problems assigned as ore-testing projects to the Ore-Dressing Section, Metallurgical Division, of the Bureau of Mines at the Mississippi Valley Experiment Station in Rolla, Mo., during the fiscal year ended June 30, 1940.]

Jan 1, 1941

By Dwight D. Trueblood

The Benthic Impact Experiment (BIE) is designed to address the effects of sediment redeposition prior to the commencement of commercial mining. The experiment is being conducted in collaboration with Russian scientists from the Yuzhmorgeologiya Association aboard the R/V YUZHMORGEOLOGIYA. Sediment resuspension and subsequent redeposition during manganese-nodule mining is predicted to be one of the primary impacts on benthic communities living on the abyssal seafloor. The redeposition thicknesses that will cause significant faunal mortality in the deep sea are unknown. Sediment redeposition could adversely affect abyssal benthic communities through entombment, or through starvation caused by food dilution and obstructed feeding. This spring NOAA conducted the main portion of the BIE experiment, blanketing the experimental area with varying thicknesses of sediment using the Deep Sea Sediment Resuspension System (DSSRS). The DSSRS was conceived by NOAA scientists, designed and built by Williamson and Associates, and is the critical piece of equipment used to generate the controlled sediment redeposition environment on the 4800-m deep abyssal plane. The DSSRS consists of an 1800-kg sled, 4.8 m long, 2.4 m wide, and 2.2 m high. The sled was towed and powered using an 8,000-m, 26-mm single conductor cable having a 3,000 VAC capacity. As the sled was towed across the bottom, mud was ingested through two rear-facing, 45-cm wide intakes using two 7.6-horsepower pumps, and discharged 10 to 20 m above the bottom through two 20-cm diameter riser hoses. Each pump was instrumented with optical backscatter sensors providing real-time information about the discharge concentration.

Jan 1, 1992

By G. W. Jones

"INTRODUCTION As part of its work in promoting safety, the Bureau of Mines is investigating various means of eliminating or mitigating the explosion hazards of combustible gases encountered in mining and industry. Information has been obtained and a procedure developed whereby the explosibility of many complex gaseous mixtures may be calculated in a rather simple manner without the necessity of performing laborious laboratory experiments. An earlier publication 3/ described the method of determining by calculation the limits of inflammability of gaseous mixtures, including methane, hydrogen, carbon monoxide, nitrogen, carbon dioxide, and oxygen. The information published in the above report permitted calculation of the limits of inflamnability of such gases as are liberated by mine fires, gases from explosives, automobile exhaust gases, gases present after mine explosions, blast-furnace gas, and other gases of similar type.Gases liberated in certain potash mines in the western part of the United States sometimes contain ethane, in addition to the gases named. An investigation was made to obtain data from which the limits of inflammability of such gaseous mixtures could be determined by calculation. 4/Similar data have been Published covering all types of natural gases containing wide ranges of concentration of nitrogen and carbon dioxide.5/"

Dec 1, 1944

By K. Häge

"Die Nachhaltigkeit der Braunkohlengewinnung in der öffentlichen Wahrnehmung wird nur weiter erfolgreich kommuniziert werden können, wenn durch konkretes Handeln glaubhaft gezeigt wird, dass die offenen Fragen fair und solide beantwortet werden. Dazu gehören insbesondere die neue innovative technische Lösung sowie das sensible Interessenmanagement. Die Braunkohlenindustrie hat gelernt, dass Offenheit und nicht zuletzt das beständige Bemühen um den Meinungsaustausch mit ihrem Umfeld wichtige Elemente sind. Der in Jahrzehnten erworbene Schatz an Glaubwürdig-keit ist eine Basis, auf der die Braunkohlenindustrie ihre Zukunft gestalten kann. Darüber hinaus sind politische Rahmenvorgaben erforderlich. Das öffentliche Interesse an einer sicheren und preiswerten Energieversorgung unter Einschluss der Braunkohle ist unverzichtbar. In diesem Kon-text kann dann die Braunkohle die an sie gerichteten Fragen der Ökonomie, der Ökologie und der Sozialverträglichkeit auch mit Hilfe von Indikatoren beantworten.ABSTRACTThe discussion of the sustainability of lignite mining can only be continued successfully if the indus-try acts in a practical manner and demonstrates trustworthiness by responding fairly and reliably to open questions. This includes new and innovative technical solutions as well as the sensitive management of interests. The lignite industry has learned that openness and the constant effort to exchange viewpoints within their environment are all essential elements. The credibility that has been gained over the decades is the foundation on which the lignite industry can build its future. Beyond that a framework of political guidelines is necessary. Public interest in a secure and inex-pensive energy supply that also includes lignite is indispensable. In this context, the lignite industry will then be able to answer the questions which are directed at them and concern the economy, ecology, and social tolerability also by indicators."

Jan 1, 2005