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By V. M. Paretsky

Most recent developments made in the Gintsvetmet Institute in the field of technologies and equipment for single-stage autogenous smelting of copper sulfide raw materials to produce white metal and blister copper on the basis of oxygen-flame smelting process and separation of highly basic calcium-containing slags have been discussed. This technology includes the oxygen-flame smelting process (KFP Process) to produce highly basic self-disintegrating ferrite-calcium slags with their subsequent flotation to recover copper and a basically new sparging smelting process (FBP Process) to produce combined slags subjected to decopperizing inside the same furnace. Results of special investigations of the slag structure obtained in the KFP and FBP processes and substantiating selection of their chemical and phase composition have been presented. It has been demonstrated that the above processes meet the stringent world-level requirements to advanced technologies with respect to energy conservation and environmental safety with different scales of production and within a wide range of specific conditions of particular operations.

Jan 1, 2006

By Harry L. Washburn

Use of coal thermal dryers has steadily increased since 1928 when one of the predecessor companies of the present Consolidation Coal Cu. constructed a complete preparation plant with thermal dryers. Today there are about 25 additional preparation plants that, all together, use over 65 individual thermal dryers of almost every type. The thermal dryer is a heat generator and the unit may have a separate furnace or a firebox that is an integral part of the dryer. It is also a materials handling device that allows an intimate mixture of wet coal and hot gases with instrumentation for temperature control and. in some cases, the more difficult flow rate of hot gases. The materials handling portion of the dryer is subject to the normal wear and teal of any similar device plus effects of heat, water vapor, moisture: and, sometimes, acid. With present emphasis on air pollution. most fine coal dryers have wet scrubbers.

Jan 8, 1963

By M. Rossi

The use of service variables in geostatistics (grade-thickness) is common in industry when developing block grade models and geologic resource estimates. This is particularly true in the case of sedimentary and stratabound-type deposits. The approach has proven merits when assessing ore reserves. However, there are cases where its application for preliminary data analysis produces biased estimates. One such case is encountered in uranium disequilibrium studies. This paper demonstrates the inadequacy of service variables when performing uranium disequilibrium studies. Disequilibrium analysis is a necessary preprocessing step when radiation counts are used as raw data to calculate uranium reserves. Typically, a probe is used to obtain the gamma counts from open drill holes. These counts are then regressed (and corrected) against chemical assays obtained from core samples. During this process the grade-thickness variable produces an optimistic image of the relationship between probe grades and chemical (true) grades, causing overestimation of the final geologic resource. The problem is analyzed through a case study.

Jan 1, 1993

By L. D. Lash, J. R. Ross

Scandium is a pseudo-rare earth which is truly rare and expensive. It has special properties which may make it desirable even at the present price of $2750 per lb. Recently the price was lowered from $5000 per lb which had prevailed since 1952, and it is anticipated that usage will be stimulated because of the lowered price. This metallic element is distributed widely in trace amounts in the rocks of the earth's crust. In addition to micro-amounts found in most uranium ores, concentrations of 50 to 100 ppm have been found in Colorado ferberite ore, lateritic nickel ore, heavy sandstone from Utah, Wyoming, and New Mexico, and various zircon sands and monazites from the western part of the US. Scandium has been found as an essential constituent of very few minerals, the most important being thortveitite, a scandium silicate. At the present time, this mineral commands a price more than twice that of gold.

Jan 8, 1961

By R. A. Pindred, M. P. Lam

Cyanide is a conventional lixiviant for gold extraction but its' toxicity is a major concern for the environmentalist. There are many alternative non-cyanide lixiviants, such as thiourea, thiosulphate, chlorine and hypochlorite etc., which may reduce environmental sensitivity. This paper will discuss the leaching characteristics of gold in hypochlorite leaching solutions. The dissolution of gold in a hypochlorite solution not only depends on the concentration of the hypochlorite but also on other variables, such as hydrochloric acid, sodium chloride and temperature. The dissolution rate of gold in hypochlorite solution is much faster than other lixiviants. Due to the interference of impurities, gold extraction from an ore under ambient conditions requires large quantities of reagents. However, refractory gold ores may be successfully pressure oxidized in an autoclave at reasonably low reagent levels. Gold extraction to the pressure oxidation leach solution is rapid and complete in one stage, thus eliminating the need for further cyanidation.

Jan 1, 1990

By Charles H. Mitchell

British Columbia is enjoying a period of sustained high-level activity in all aspects and sectors of its mining industry. The total value of mineral production for 1962 was in excess of $229 million. This was the greatest total value attained for any year to date, exceeding the previous record year of 1956 by more than $40 million. It appears reasonable to expect that value of production for 1963, stimulated by increased production attained during the year, and by improved metal prices for some of the major products, will be substantially in excess of that recorded for 1962. Elsewhere in this issue appears a detailed report of prospecting and exploration activity in the Province. For the purposes of this review it is sufficient to state that the level of prospecting and exploration activity during the past several years has been greater than at any previous time and that there does not appear to be any slackening in activity or interest.

Jan 12, 1963

By Shaolong Chen

Feeding dry sulfide concentrate into smelting furnaces enhances process performance and reduces the energy consumption and exhaust gas flow. Direct heated rotary dryers and flash dryers have being replaced by rotary steam dryers featured by very low wear rate of the pipe heating elements and long maintenance interval. Impact of the drying processes on the environment receives more and more attention as the emission legislation tightens. In this regard, environmental factors such as SO2, CO2, dust and gas flow among rotary dryers, flash dryers and steam dryers were compared. Selection of a rotary steam dryer for copper and nickel concentrate drying would be an ideal solution to reduce the pollution of exhaust gas, as drying is achieved by indirect contact to the steam at relatively low drying temperature and as the off-gas contains almost only water vapor and air. The emissions can be significantly reduced and only small and simple off-gas handling units are needed.

Jan 1, 2006

By N. S. Dalal, Xianglin Shi

Metal ions, such as chromium (Cr) and vanadium (V) are found as trace impurities in mineral dust. Since metal ion mediated free radical generation has been implicated in many disease processes, we carried out a detailed investigation of the metabolism of these metal ions by biological redox systems and the possible oxygenated radical generation therefrom. We found that highly reactive Cr(5+) species are generated in the reduction of Cr(6+) by NADPH-dependent glutathione reductase, lipoyl dehydrogenase, and ferredoxin-NADP+ oxidoreductase. The reduced metal ion species react with hydrogen peroxide, to generate hydroxyl (•OH) radicals in a continuous cycle. The enzymatic catalysis processes also involves the reduction of molecular oxygen to the superoxide [(0-1 2)] radical. Thus only a trace amount of metal ions chemisorbed on mineral dusts, such as quartz, can catalyze the generation of the highly toxic oxygenated radical species from cellular hydrogen peroxide, suggesting a new biochemical mechanism for mineral dust induced chronic lung injury.

Jan 1, 1991

By Thomas J. Ferree

The principle mineral concentration practices today can be divided into three basic process categories: magnetic separation, flotation and gravity separation. The basic processes have been in use for many years with only limited changes occurring in equipment design or process technique. In general, equipment and process techniques have been altered only after a need for change has developed. With exceptions for changes necessitated by new environmental laws, most equipment and process improvements have evolved in accordance with the desire to concentrate larger quantities of material at lower costs. The basic result has been the development of larger capacity equipment, to wit: larger flotation cells, larger blast furnaces, larger haulage equipment and larger chemical process equipment. However, there has been practically no changes in the size of spirals, tables, jigs, or-within limits- magnetic separators. (The exception being high-intensity magnetic separators). Consequently, a "new" device has entered the scene which may fill a void in the gravity separation field. It is called a Reichert cone concentrator.

Jan 3, 1973

By K. Th. Mavrommatis

Cleanness of steel is justified, measured and estimated in steelmaking process through different concepts which are mainly based on operational, empirical or semiempirical parameters and describe ?cleanness as a state?. In this work a theoretical concept is developed, considering ?cleanness as a process? and introducing a dynamic aspect into the quantification of cleanness of a steel melt, linking operational parameters with physicochemical variables, which are based on first principles. This concept and the here derived and developed variables and parameters are based on the earlier defined agglomeration index (AI) of a steel melt, the ratio of the mean inclusions diameter (MID) to the mean inter-particle distance (MIPD), which is shown to be a measure of the agglomeration tendency of the melt after deoxidation, and can serve both, to monitoring cleanness during steelmaking operation and to be useful as a basis for mathematical modelling of cleanness and of the metallurgical measures in plant, associated with production of clean steels.

Jan 1, 2006

Discussion of the paper of Robert Franke, presented at the Butte meeting, August, 1913, and printed in Bulletin No. 79, July, 1913, pp. 1201 to 1205. ARTHUR 0. GATES, Lafayette, Ind. (communication to the Secretary*) :-In connection with the comparison of mechanical crushing efficiencies in Tables I and II of Mr. Franke's paper, I wish to suggest a somewhat simpler way of making this' comparison, based upon what the writer has called the "crushing-surface diagram," as published by him in the Engineering and Mining Journal for May 24, 1913. Such a diagram, based on the data given in Table II, is submitted herewith, Fig. 1, cumulative percentages being plotted as abscissas and reciprocals of diameters (theoretical mesh per inch). plotted as ordinates.. Such a diagram averages the diameters without calculation, and areas upon it are proportional to surface produced, and, in accordance with Rittinger's law, to energy spent on crushing alone.

Jan 11, 1913

By R. L. Schmidt, Williamson. T. N.

INTRODUCTION This paper describes one of several research projects funded by the Advanced Research Projects Agency to extend the technology of rapid underground excavation. This study and field research effort are to investigate alternative means to determine rock and geological conditions in advance of a tunnel boring machine (TBM). Approximately 1 year of a planned 3-year program has resulted in the definition of three candidate drill systems. Hardware has been assembled to field test these candidates and testing has begun. The 3-year objective is to develop a single optimum prototype drill and test it in an active TBM operation. ACKNOWLEDGMENT This research was supported by the Advanced Research Projects Agency (ARPA) of the Department of Defense and was monitored by the Bureau of Mines under Contract No. H0210037. The authors and sponsoring agencies are indebted to the quarry operators in California, Virginia, and West Virginia who offered assistance including access to their properties.

Jan 1, 1997

The past year has been a difficult one for the mining industry in this country, but an active and successful one for the Branch. Membership has continued to increase, albeit at a slower rate than last year, and with the increase almost all from student membership. I dwelt at some length last year on the continued increase in student membership, which I ascribed largely to deliberate policies adopted by the Branch to foster this area of membership. I don't propose to reiterate these, suffice it to say that as usual, the Otago School of Mines has been a prolific source of student members, and it will be a pity if this source dries up û more on this subject later. In fact, students form just on 29 per cent of the Branch's total membership û a far higher percentage than for any other Branch in the Institute, whose membership as a whole comprises only ten per cent students.

Jan 1, 1985

One Hundred and Twelfth Meeting of the Institute, Monday, February 14, to Thursday, February 17, inclusive, 1916 COMMITTEE ON ARRANGEMENTS DAVID H. BROWNE, Chairman. BRADLEY STOUGHTON, Vice-Chairman. LAWRENCE ADDICKS, BURR A. ROBINSON, P. E. BARBOUR, E. M. SHIPP, G. D. BARRON, JOSEPH STRUTHERS, J. V. N. DORR, E. B. STURGIS, J. R. FINLAY 'R. H. VAIL. L. D. HUNTOON, Hotel Accommodations.-The Committee on Arrangements is canvassing a number of hotels in New York City, securing .wherever possible special rates to members and guests for the clays of the meeting. It is possible to secure good accommodations on very reasonable terms in New York City if one knows where to look for them. A list of hotels and rates will be published in the final announcement of the meeting, which will go to the members about the middle of January, in order that those who desire to secure good hotel accommodations at a reasonable mice may have the information.

Jan 1, 1916

By H. M. Merry

THE graphic methods and records described in this article have been developed, with satisfactory results, for the use of executives of the Chino Copper Co., in Hurley, N. Mex. Particular attention is directed to the use of large wall-charts, the quick reference display of large charts, the scale notation of metallurgical charts, the inclusion of mesh extraction on screen analysis diagrams. To properly comprehend the operation and metallurgical results from a concentrating plant, a daily record of essential data is kept, usually involving the dry weight of ore milled or treated, dry weight of concentrate or metal produced, assay values of heading, assay values of tailing, assay values of concentrate, and percentage of extraction or recovery. In addition it is often necessary to record moisture, pulp density, or dilution; percentage of weight of oils and reagents employed; screen analyses of grinding conditions, oversize, etc.; assay values of non-valuable or interfering substances; cost data; and such special information as may be required.

Jan 9, 1919

By Walter W. Fisher, Samuel Rudy

Secondary treated sewage effluent was substituted for normal process water in laboratory tests simulating froth flotation recovery of copper and molybdenum sulfides. Sewage effluent caused significant detrimental response in the flotation process. First, a voluminous, uncontrollable froth was generated, even in the absence of a frothing agent, that has little mineral carrying ability. Second, sewage effluent caused a small loss in copper recovery and a large loss in molybdenum recovery. The detrimental effects of sewage effluent on flotation were partially overcome by tertiary treatment of the effluent by activated carbon adsorption and anion exchange. The frothing problem was significantly reduced after treating the sewage effluent by foam fractionation. Dilution of the effluent with normal process water resulted in a significant improvement in metal recovery. In addition, the large loss in molybdenum recovery was overcome by using a secondary collector in a combination reagent schedule. However, the secondary collector caused an appreciable loss in copper recovery.

Jan 1, 1979

By W. M. Tuddenham, R. J. P. Lyon

In many areas surrounding the orebodies in mining districts rocks have been bleached and altered by the ore-forming solutions and have been oxidized during later weathering processes. A number of the rock-forming silicates have been broken down to clay, sericitic micas and chlorites have been developed, and pyrite may be found hundreds of feet outside the economic limits of the orebody. These halos of altered ground are prime targets used by geologists in many districts to delineate promising sites for drilling. Both in the field and in the laboratory it is often difficult to map these mineralogical changes in the halos in detail without numerous petrologic examinations. The secondary minerals are generally fine-grained, and since conversion of one mineral to another is often progressive, many alteration processes have not proceeded to completion (feldspars to clay to sericite mica). Qualitative detection of these minerals is difficult; quantitative determination is frequently impossible.

Jan 12, 1959

By K. N. Han, M. C. Fuerstenau, T. B. Onlin

A mathematical model describing the concentration profile of fine particles in the axial direction in liquid fluidized beds has been developed for the removal of fine particles. A forward finite differentiation technique has been used to solve a continuity equation with a source term to predict the concentration profile and, hence the recovery as a function of time. With the aid of experimental results obtained using a fluidized bed of 3-cm diam, dimensionless parameters were identified. These parameters were used to predict the concentration profile of fine particles in fluidized beds of larger sizes. Four different sizes of fluidized beds, namely, 1.3, 3.0, 4.0, and 7.5 cm in diam, were used in this investigation. The amounts of bed particles used included 4, 8, 16, 24, 59, and 120 g, and the size of bed particles were 48x100, 100x150 and 150x200 mesh.

Jan 1, 1987

By Charles L. Karr

Researchers at the University of Alabama in cooperation with the U.S. Bureau of Mines have developed adaptive process control systems in which genetic algorithms (GAS) are used to augment fuzzy logic controllers (FLCs). GAS are search algorithms that rapidly locate near-optimum solutions to a wide spectrum of problems by mimicking the search procedures of natural genetics. FLCs are rule based systems that efficiently manipulate a problem environment by modeling the "rule-of-thumb" strategy used in human decision making. GAS and FLCs can be combined to produce powerful, efficient, and robust adaptive control systems. To perform efficiently, such control systems require a control element to manipulate the problem environment, an analysis element to recognize changes in the problem environment, and a learning element to adjust to the changes in the problem environment. I" this paper, the details of an ongoing research effort to develop and implement an adaptive process control system for a column flotation unit are discussed.

Jan 1, 1996

By W. Setzepfandt, J. Henneke

PREFACE Debris disposal can very often be a severe problem and major restriction on tunnel boring projects, especially for small diameter tunnels and in underground mines. Hydraulic transport could provide a suitable solution. Investigations have therefore been made in connection with a full-scale project of 4.8 km length and 2,3 m diameter, to obtain the required technical and economical data for planning an optimized transport system, e.g. for a tunnel boring drivage of 6 - 7 m diameter in underground coal mines. INTRODUCTION The Radau-Tunnel, chosen for the investigations, has been designed for transferring flood peaks between the rivers Radau and Grosse Romke in the Harz-Mountain of Lower Saxony. A DEMAG TVM 20/23 H tunnel boring machine was used to drive the tunnel on a rising gradient of 0,53 %. The rock consisted of shale and hornblende (55 %), granite (15 %), diabase (15 %), chert (8 %) and gabbro (7 %). The project has been sponsored by the Federal Ministry of Research and Technology.

Jan 1, 1981