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By T. L. Iapalucci

To determine the behavior of chlorine in coal combustion, the Bureau of Mines burned 10 chlorine-containing coals, high-, medium-, and low-volatile, in a laboratory-scale pulverized-coal combustor. At carbon-combustion efficiencies of 94 to 98 percent, 1.6 to 7.1 percent of the chlorine or an average of 4 percent of the chlorine in the coal was retained in the ash; the balance, predominantly hydrogen chloride, was evolved in the combustion gas. Sulfur retention in the ash ranged from 2.3 to 10.7 percent or an average of 6.3 percent, Addition of alkali and alkaline earth carbonates to a medium-volatile coal containing 0.27 percent chlorine by preferentially reacting with the chlorine increased the Cl/S atom ratio in the ash, Lithium carbonate addition at 0.43 percent and K2C03 at 1.59 percent increased the C1/S ratio in the ash from 0.2 to 0.6.

Jan 1, 1969

By C. C. Furnas, T. L. Joseph

It is well known that particles of different sizes are not distributed evenly throughout the average charge in an iron blast furnace. Just how great the disparity in particle size in different parts of a single plane in a furnace may be is indicated by the results of some recent investiga-tion1,2 conducted by the Bureau of Mines on a furnace operating on Lake ores. The wide variations found in gas velocity, gas composition, and temperature from the periphery to the center of the upper charge column were caused by the great variation in particle size of the raw materials used and were also greatly influenced by the methods of charging. This paper summarizes the results of an investigation of the influence of different methods of charging and of the treatment of raw materials upon the size distribution of the solid particles in the blast furnace. A more complete report will appear later as a Bureau of Mines technical paper. Importance of Gas-solid Contact One of the authors has pointed out in a previous report? that the operation of the blast-furnace process is entirely dependent on contact between the gas stream and the solid particles in the stock. The gas stream carries the necessary heat as well as the carbon monoxide molecules that do the work of rednction. In the parts of the furnace in which there is little or no contact between the gas stream and the solids there can be little work of reduction. Obviously, the part of the apparatus that is not doing the work for which it is intended is inefficient; the ideal condition is one in which all portions of the stock column are

Jan 1, 1929

By W. M. Mahan

This report describes work carried out by the Federal Bureau of Mines in cooperation with the General Services Administration (GSA). Tests on nickel oxide reduction were conducted at the Pyrometallurgical Laboratory at Pitts-burgh and Bruceton, Pa., and at a rented plant at Canonsburg, Pa. Nickel oxide was reduced to sponge nickel, which was then melted to produce specification-grade nickel ingots containing a minimum of 98.50 percent nickel plus cobalt and a maximum of 1.00 percent cobalt. One purpose of this study was to determine if specification-grade nickel could be made from nickel oxide produced at the United States-Government-owned plant at Nicaro, Cuba, in pilot-plant scale operations involving direct reduction and melting processes. A second and equally important purpose was to obtain cost data on the pilot-plant operation to estimate the cost of producing ingot nickel at an annual rate of 12 million pounds. Laboratory tests verified that nickel oxide, in saggers and in the presence of anthracite fines and dolomite in the ratio of approximately 20:5:1, could be converted to sponge nickel when heated to approximately 1,900° F. for about 2 to 4 hours, depending on the size and density of the oxide charge. The tests also determined the type of saggers suitable for pilot-plant operations.

Jan 1, 1959

By Peter Hood

Data on worldwide geophysical activity in mining exploration programs is collected annually by the Geophysical Activity Committee of the Society of Exploration Geophysicists as part of a continuing service to the industry. The data is obtained by sending out questionnaires to all organizations (which are) known to be carrying out mining geophysical work; the organizations canvassed include mining companies, contractors, government departments and universities. The questionnaire is divided into three sections, namely ground methods, airborne methods and research. In 1968, 515 questionnaires were circulated throughout the non-Communist world and 283 replies were received which is a 55% return. A 67% return was received from the U. S. organizations surveyed so the statistics quoted in this report for the United States are reasonably reliable. This report is published in condensed form, but with emphasis on the United States statistics, with the permission of the Society of Exploration Geophysicists. It was presented at the 39th Annual International Meeting of the SEG in Calgary, Alberta, on September 15, 1969. Worldwide utilization of mining geophysical methods reached a new high in 1968 with total expenditures of United States $41.4 million, compared lo $32.3 million in 1967, representing a 28%, increase. The expenditure distribution by area and type of activity is shown in the graph on page 64. In terms of money spent, ground geophysical surveys accounted for 49% of the total, airborne survey's 36% and research 15%. The percentage of the money spent on ground geophysical surveys fell by approximately 7% from 1967, that for airborne surveys, increased by 5%, and for research the amount increased by 2%. Industry accounted for 79°1% of the total monies spent on mining geophysical activity in the world in 1968 and governments and universities 21 o%.

Jan 1, 1970

By T. T. Chen

Secondary copper anodes are generally rich in Sn, Pb, Ni and Sb, but are notably deficient in Se, Te and Ag. In the secondary copper anodes, most of the Ni, virtually all of the Ag, slightly more than one-fifth of the Pb, about one-third of the As and Sb, and approximately one-tenth of the Sn are in solid solution in the copper. The remaining impurity contents occur as 1-5 µm grain-boundary inclusions in the anodes, and these are mainly Cu2O, SnO2, Cu-Pb-As-Sb-Bi oxide, Pb-Sb oxide, Sn-Ni-Zn oxide, Cu-Sn-Ni oxide, Cu-Sb-Ni oxide (Kupferglimmer) and trace Cu2(Se,Te). Barium sulphate, which originates from the mold wash used in casting, is also present in the anodes. During electrorefining, the BaSO4, SnO2, Pb-Sb oxide, Sn-Ni-Zn oxide, Cu-Sn-Ni oxide and Cu- Sb-Ni oxide inclusions are liberated and accumulate in the slimes layer. Solid solution Ni dissolves and the Ni accumulates in the electrolyte. Solid solution Sn and Pb dissolve, but partly reprecipitate as Sn arsenate and PbSO4, respectively. Solid solution Ag dissolves but rapidly reacts to form Ag2(Se,Te), Ag powder, Ag-bearing Cu2O, (Cu,Ag)SO4 or a complex oxidate phase. Partial dissolution of the Cu-Pb-As-Sb-Bi oxide particles takes place; the Pb component is converted to PbSO4, whereas Cu, As, Sb and Bi dissolve. The reacted particles retain the morphology of the original Cu-Pb-As- Sb-Bi oxide phase. Some of the solubilized As, Sb and Bi remains in solution, but much reprecipitates as SbAsO4, As-Sb-Bi oxide, and as a poorly defined oxidate phase which consists mostly of Cu-Ag-Pb arsenate-sulphate. The high Sn contents of secondary copper anodes do not seem to affect the behaviour of the anodes during electrorefining.

Jan 1, 1999

By Shichang Liu, Hongli Jia, Zhaolian Wang, Maotang Liu, Ltd. Shandong Huate Magnet Technology Co., Fengliang Liu

"Introduce and promote a latest technology and equipment for magnetite. It’s featured of purifying concentrate, lowering tailing grade, high concentrate recovery rate and stable operation. HUATE® New Style Elutriation Electromagnetic Separator is an equipment to obviously upgrade magnetite. The slurry is fed into separation area through feeder. Generated by excitation coil, the working magnetic field distributes specially in separation area. Under the combined effect of the background field, excitation and demagnetic field and gravity, the mineral particles float downwards in the form of magnetic chains, and interact with the rising water. The gangue, non-magnetic particles, lean intergrowth,etc will be discarded as tailing via overflow tank and pipe. While the magnetic will be discharged from concentrate pipe. Its grade is 2%-10% higher than that of traditional magnetic separation equipment. It adopts the technologies of transformer oil cooling, alternative and uniform pulsation magnetic field controlling the tailing grade, larger drum feed-in device, more uniform umbrella scattering discharge and stabler output current, and realizes lower coil temperature raise, stabler magnetic field, more uniform discharge, effective isolation of weak-magnetic area from non-magnetic area, more obvious upgradation and recovery rate and lowering tailing mFe%. It’s more suitable to purify and thicken the high grade and ultrafine iron powder. Compared with traditional elutriation equipment, it adopts new technologies in removing impurities, operation, large-scale, process simplification, water-saving, remote control, etc. It optimizes the comprehensive beneficiation index, expands its application scope, reduces resource wastes and increases economic benefits.INTRODUCTIONMagnetite accounts for a comparatively great proportion in various iron resources. As it’s a kind of strong magnetic mineral, we must adopt the weak magnetic separation equipment in magnetic separation process to realize removing Si and lowering impurities. While it cannot do very well to use the common weak magnetic separation equipment in the final cleaning to remove Si and lower impurities. At present, the plants, adopting single magnetic separation process to realize cleaning and removing Si and lowering impurities, are in the minority. Most magnetite plants adopt the flotation separation process to remove Si, lower impurities and purify the concentrate. Though with stable indexes and high Fe recovery rate, the flotation process is very complicated, high-cost and with lots of environmental pollution. If adopting the weak magnetic separation equipment can realize removing Si, lowering impurities and the final cleaning, the magnetic separation process should be the primary choice."

Jan 1, 2016

By G. Norman Owen, Roger E. Scholl, Tor L. Brekke

INTRODUCTION Underground structures are generally regarded to be safer than surface structures during strong seismic motion, except when crossing a causative fault. Recent studies of observed earthquake damage to tunnels generally support this view, although instances of severe damage and, occasionally, collapse are reported. For proposed underground construction of sensitive structures such as nuclear power plants, liquefied natural gas facilities, and nuclear waste repositories, a verification of the seismic response of underground structures will be required.. This paper discusses the stabilization recommendations used in a study of additional costs required to protect tunnels against ground motion caused by earthquakes and underground nuclear explosions (1). The study is a part of the site investigations for possible construction of a nuclear waste repository. The additional costs estimated in the study are not presented here; only the stabilization measures are presented in the present paper. The tunnels, which would constitute the underground facilities of a possible repository, are assumed to be 5.5 m (18 ft) in diameter and to be located at a depth of 600 m (2,000 ft). Three candidate geological materials are considered: argillite (shale), granite, and tuff. Several peak ground accelerations are used: 0.3g, 0.5g, and 0.7g for earthquakes, and 0.5g, 0.7g, and 1.0g for underground nuclear explosions. Potential damage due only to shaking is considered here. This paper does not discuss problems that result from creep or sudden rupture of intersected faults or from ground failures at portals.

Jan 1, 1979

By J. H. Brown

"THE need for continuing education has been recognized only in fairly recent years as a major concern of the engineering profession. Formerly, it was acknowledged that engineers were required, at least informally, to follow the professional literature and to give some attention to new technical and technological developments. However, those relaxed days, when progress could be followed in a casual or incidental evening of reading, have disappeared in these days of mushrooming information. The engineer is now in the position of the man trying to control the flow from a fire hydrant with a child's pail. Our problem is that of developing an effective flow system -be it trough, hose, pipe or a bigger pail.The first step in achieving an effective means for continuing the education process is to realize that the need for the system is really an outgrowth of an increasingly sophisticated society. It is merely one more symptom of that society; others would• include the facts that new engineering graduates are more highly trained than those of several years ago, that graduate schools are now the norm and that even some fairly recent technologies are becoming outdated. There-fore, let us examine the education-al systems from which the bulk of the increasing sophistication has grown."

Jan 1, 1966

By J E. Powalisz

"The application of automated sampling techniques can help to provide a representative sample of process fluids and slurries that provide data for controlling process, custody transfer and quality assurance and quality control purposes.The automation of sampling provides a more consistent and reliable sampling process and eliminates many of the human-induced errors. Automated sampling can also provide a higher degree of safety in the plant/processing environment as well as better bottom-line results.Automated, fixed volume samplers can provide a very representative sample by integrating many small ‘grabs’ of sample from a process. Automated samplers can be controlled in a variety of ways to optimise the sampling process, including:cycle ratedwell timetotal volume.Properly selected and applied, an automated sampler can effectively isolate the operator from the process fluid during sampling and, to a great degree, during sample container collection.A variety of materials of construction, including seals, are available to handle demanding mining applications. Alloy 625, alloy 2205, AL6XN® and even certain plastics are used successfully in mining slurry applications.This paper explores the application of automated, fixed volume, batch style samplers in copper/nickel and gold processing, specifically pregnant leach solution and extraction fluids.Several specific field applications are discussed, including process installation details, hardware and operation.CITATION:Powalisz, J E, 2014. The application of automated samplers in copper/nickel processing, in Proceedings Sampling 2014, pp 35–42 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 29, 2014

By R. A. Vandermeer, P. Gordon

The study of recrystallization in cold-worked metals is complicated by the impossibility of making direct three-dimensional optical measurements. Metallo-graphically, theinternal three-dimensional features of samples must be inferred from their intersections with the two-dimensional plane of polish. The inherent difficulties involved in this procedure have led— particularly during the last few years—to some instances of rather doubtful interpretations of experimental data in terms of nucleation and growth rates in recrystallization. In the present paper an analysis ; is given of the recrystallization characteristics in a polycrystalline alloy containing 0.008 wt pct copper in ZONE-refined aluminum *and an effort is madf to reemphasize the necessity in such studies for attention to the proper statistical relationships between one- two- and three-dimensional features of opaque samples. It is shown that, in common with several recently described cases for other types of transformations,1-5 recrystallization in this alloy can best be rationalized on the basis that all nucleation took place essentially at time zero—i.e., there is no significant time-dependent nucleation during annealing—and that the kinetics are controlled exclusively by the growth-rate parameters. This is true despite the fact that the number of

Jan 1, 1960

By Grant Buma

The purpose of this paper is to present arguments and evidence that there are natural processes at work which tend to minimize the impact of solution mining on the environment. The contaminants have two sources. First are elements which were present in the roll-front deposit in insoluble compounds, for example, uranium in uraninite and coffinite, molybdenum, arsenic, iron, cobalt, nickel, etc. in sulfide minerals, vanadium in micas and clays, etc. Second are elements introduced by the leach liquor. Precipitation of reduced compounds, scavenging of heavy elements and absorption by quartz and clays, can all reduce the amount of heavy elements in solution. If a roll can be demonstrated to be actively precipitating uranium and heavy metal elements, then the presence of precipitants (pyrite and carbon) can be assumed. Criteria for recognizing an active roll are described.

Jan 1, 1979

By Robert A. Bruce

A motion transducer based on coherent mixing of laser light backscattered from rough surfaces is evaluated in terms of sensitivity, bandwidth and range. Tests made with a prototype composed of a 4-mw HeNe laser, a silicon avalanche photodiode, and a 15-cm aperture telescope demonstrate that remote measurements with reasonable bandwidth and accuracy are feasible at distances up to 100 meters.

Jan 1, 1977

Reducing Fusion: The impure or low grade uranium concentrate is mixed with a formulated flux of sodium carbonate, salt, and sawdust or fuel oil and heated, while being stirred, to about 950°C. This reduces the uranium to the black, water insoluble uranium dioxide and with the exception of nonamphoteric metals forms water soluble sodium salts of the vanadium, alumina, silica, phosphates, and other constituents of the cake. The cooled melt is then water leached, leaving a residue of black insoluble uranium dioxide. "Green Sludge" Digestion and Liquor Purification: The green sludge is redissolved in acid, and by selective precipitation involving pH adjustments and a final neutralization

Jun 1, 1956

By Mark S. Stagg, Stephen A. Rholl, Steven G. Grannes

A method of determining the fragment size distribution of rock quarry muckpiles using photographic and digital-image processing techniques has been developed by the Bureau of Mines. To assess the fragmentation, photographs and video tapes were taken in both the laboratory and in the field and then digitized for analysis. The fully-automated process uses specially written image-interpretation software which had been developed previously by Bureau researchers to measure irregular taconite ore shapes. The advantages of photographic assessment in comparison with other methods include speed and cost.

Jan 1, 1993

By Hernán Zapata

"El presente trabajo describe el proceso de recuperación del oro y plata en diferentes medios, utilizando un biopolímero o derivado de la quitina proveniente del caparazón de langostinos. La quitina calcárea, después de la celulosa, es el segundo polímero más abundante en el planeta, cuya ventaja estriba en el poder de sorción en la plata y su bajo costo en comparación con el quitosan. El estudio se realizó con soluciones estandarizadasde oro y plata en medio ácido y medio básico, éste último conteniendo además cianuro en solución."

Sep 14, 2009

By Ricardo Vega Márquez

La mineralización en Cerro de Pasco se localiza estructuralmente en la cresta y flancos de un anticlinal de doble hundida y parte de una falla longitudinal. El contacto entre estas calizas conlleva el control litológico para la deposición de plomo-zinc. En este sentido, el objeto del texto es crear un programa de sondeos de perforación diamantina a escala del yacimiento en la mina subterránea para verificar este mineral potencial. Asimismo el agua proveniente de estos sondajes, se utiliza para usos industriales o domésticos puesto que los reservorios naturales de superficie son insuficientes.

Oct 14, 1980

By J. S. Li, J. C. Edwards

A prediction is made of the airflow at the Bureau of Mines Lake Lynn Laboratory with a ventilation computer program that accounts for fan-driven forced ventilation and temperature-induced natural ventilation. There was substantial agreement between measured and predicted airflow rates. The capability of the program is demonstrated as a planning aid for ventilation under emergency conditions in a multilevel coal mine. Smoke spread in a multilevel mine is analyzed following the occurrence of two events, the failure of the main exhaust fan and the development of a fuel-rich fire in a passageway.

Jan 1, 1983

By Akihide Hosokawa

The void growth and coalescence in model materials involving a pre-existing three dimensional void array (i.e. multiple layers of a void array) was studied by X-ray computed tomography (XCT) coupled with in situ tensile deformation. To reduce the recording time, a new technique called fast tomography was employed. The model materials used in this paper were fabricated by the combination of an ultra-short pulsed laser machining system and a diffusion bonding technique, and two different types of arrays were prepared namely, FCC 1 and FCC 2 type array. This methodology allowed the authors to capture the entire process of growth and coalescence events of a void array embedded in the metal matrix. The failures in the both materials involved internal necking and shear localization. One of the highlights of this paper is that the plastic strain at the onset of void coalescence was measured for each model material. These values are in fact the adequate values to be compared with the coalescence strain predicted by existing void coalescence models such as the Brown and Embury model, the Thomason model and the Pardoen and Hutchinson model. The comparison suggested that the Brown and Embury model underestimated the coalescence in neither of the current model materials, while the Thomason model and the Pardoen and Hutchinson model showed a quite good agreement with the result for FCC 1 material. On the other hand the result from FCC 2 material agreed with none of the models probably due to the geometry of the void array that is not compatible with the existing models.

Jan 1, 2010

By Donald W. Gentry

This section deals with one of the most fascinating aspects of mining the evaluation of mine investment opportunities. Be-fore proceeding further, it is important to clarify the meaning of some fundamental terms used frequently in the text. 6.0.1.1 Mine Valuation vs. Evaluation The words "valuation" and "evaluation" in a mining context are often used interchangeably. However, for the purposes of this section, a distinction is made between the two terms in accordance with commonly accepted practice. The word valuation in a mining project context has the rather narrow meaning of placing a dollar or other currency value on the worth of the project as a whole. In other words, the value of a mining project refers to a measure of the desirability of ownership of that property. As such, the major item of interest is, "what is the mine worth?," or `what is the value of the mine?" The value of a mining project may actually be determined in the marketplace at any specific point in time, or it may be estimated by one of several methods. The topic of mine valuation is discussed in more detail in Chapter 6.1. The word evaluation in a mining project context connotes the broader meaning of determining the numerical values of all

Jan 1, 2008

By Wojciech Klecan

Cobb County, located on the northwest side of Atlanta, GA, is continually growing and, like many other metropolitan areas, it needs to increase the capacity of its waste water system to meet future demand. The Cobb County Water System (CCWS) is the responsible agency for water distribution, waste water collection and treatment in most areas of the county. CCWS, one of the most progressive agencies in the metro-Atlanta area, is addressing its future waste water capacity needs in the southern part of the county with the construction of the South Cobb Tunnel and Pump Station. This project consists of an 8.8-km- (5.5-mile-) long, 8.2-m- (27-ft-) diameter, tunnel boring machine (TBM) excavated waste water storage and conveyance tunnel; six tangential vortex-flow intakes ranging from 1,533 to 5,700 L/s (35 to 130 mgd) peak flow capacity, two construction shafts, six 1.8-m (6-ft) finished diameter connecting tunnels ranging in length from 6 to 975 m (20 to 3,200 ft) and a 5,700-L/s (130-mgd) wet/dry pit pump station. The pump station will have a semi-circular wet well with a dividing wall that extends almost to the top of the shaft and a spilt dry well for reliable operation. Roller gates will control the flow to the wet well from the tunnel. The pump station will have six 1,420 L/s (32.5 mgd) pumps and two sets of stair wells and elevators. With a finished diameter of 32 m (104 ft) and a depth of 62 m (204 ft), this is the largest pump station shaft constructed so far in Georgia for the dewatering of a waste water tunnel. The pump station shaft was also the highlight of the well attended and successful 2009 Shaft Design and Construction Short Course held in Atlanta, Sept. 10-11. The two-day course was sponsored by the Underground Construction Association of SME and Pennsylvania State University and concluded with a field trip to the pump station shaft. The tunnel starts south of the city of Austell and finishes at the South Cobb Water Reclamation Facility (WRF), located on the banks of the [ ] Chattahoochee River just north of Interstate 20 (Fig. 1). The South Cobb Tunnel will run 30 to 137 m (100 to 450 ft) below the surface, with an average depth of about 91 m (300 ft), through metamorphic rocks (Fig 2). The construction contract was awarded to Shea-Traylor JV with the lowest bid price of $305 million and notice-to-proceed was given on July 14, 2008. Jordan Jones & Goulding, Inc. (JJG) is the project designer and performed the geotechnical investigations. Parsons/Jacobs Associates is the construction manager. The South Cobb Tunnel is CCWS?s second deep hard rock tunnel. The 15.3-km- (9.5-mile-) long, 5.5-m- (18-ft-) diameter TBM excavated the Chattahoochee Tunnel was the first deep tunnel to be construced in Cobb County. Construction began in 2000 and the project was completed four years later. It is located about 16 km (10 miles) northeast of the South Cobb Tunnel in similar geology. It was designed by JJG to meet east Cobb?s long-term waste water capacity needs and provide flow equalization to the R.L. Sutton WRF. The Chattahoochee Tunnel was named ?Outstanding Civil Engineering Project of the Year? by the Georgia Sec-tion of the American Society of Civil Engineers in 2006.

Jan 1, 2009