Search Documents

By R. Venugopal

Hydrocyclones have been used extensively for more than 100 years to classify mineral slurries for recirculation in grinding circuits. Sometimes hydrocyclone classification is carried out in more than one stage to improve the efficiency of classification. Factors affecting separation efficiency include fluid velocity, density, and viscosity as well as the mass, size, and density of the particles. The geometric configuration also affects its efficiency; it includes parameters like cyclone diameter, underflow and overflow diameter, position of vortex finder, height of the cyclone, feed inlet geometry, and diameter etc. Besides changes in the basic parameters some modifications in cyclone has also been introduced from time to time which have affected its efficiency, some of these are :-(i).Introduction of magnetic force along with the centrifugal and drag force to control the flow of the magnetic particles inside the chamber.(ii). Introduction of sparger, air is introduced in the chamber in the form of bubbles, to control the flow of fine particles and hydrophobic particles. (iii). Introduction of dilution technologies for the dilution of thickened underflow. (iv).Introduction of new model. In spite of wide use and simple geometry, the real working principle of hydrocyclone chamber is extremely complex because of the swirling turbulent flow inside the device. In order to get more knowledge about hydrocyclones and to increase its efficiency, past 10-15 years simulation techniques are being developed. The simulation models also enabled a deeper insight into the static and dynamic behavior of hydrocyclones. Therefore, more emphasis on simulations by methods like Computational Fluid Dynamics (CFD), Finite Element method (FEM) is given. Overall, a status review of the work carried out on the analysis of hydrocyclone performance, modeling approaches and its contribution in the efficiency of mineral processing operation is highlighted.

Sep 1, 2012

By R. L. Atwood

The structure, properties, and composition of commercial chelating-type copper extractants are examined. Characterization of these extractants was accomplished using organic separation techniques and analytical tools such as NMR and IR. Results indicate that only the trans isomer of the diphenylhydroxyoxime (LIX (R) 64N) is capable of copper chelation. The effect of the structural modification of the extractants on the extraction and stripping reactions are discussed.

Jan 1, 1972

By Michael Harley, E. Guy Charlesworth

"Abstract - Bedding-parallel thrust-hosted gold veins are developed in the Sabie-Pilgrim's Rest goldfield, eastern Transvaal, South Africa. The reefs display a complex history characterized by temporally and spatially overlapping events of similar mineralization and deformation. Recognition of the episodic reactivation of these low angle (5° to 10°) thrust faults implicates high fluid pressures (equalling or exceeding lithostatic pressures). Geochemical constraints limit the amount of fluid-rock interaction and the occurrence of transgressive mineralization within the Archaean granitoid basement suggests that the high pressure fluids originated at depth beneath the Transvaal Basin.Similarities exist between gold deposits of Sabie-Pilgrim's Rest and Telfer, Western Australia as well as Passagem de Mariana, Minas Gerais, Brazil. All deposits are sub-parallel to the enclosing bedding which is shallowly inclined. Furthermore, they are also hosted by contractional deformational structures and are clearly epigenetic in origin."

Jan 1, 1994

By The Staff

THE property of McKenzie Red Lake Gold Mines, Limited, consists of eleven claims located on McKenzie island in Red lake. The mine is about 4,Y:l miles by water from the Howey townsite on the same lake, and about 95 miles north of Kenora, Ont. (see Figure 4). Mail and express are flown-in daily, winter and summer, from Sioux Lookout, Hudson, Kenora, and Winnipeg. All heavy supplies are freighted-in during the summer over a water route, using four marine railway portages, from Hudson, Ont., a distance of about 180 miles. During the winter, freighting over the same route is clone by tractor if necessary, but costs are three to four rimes the summer rate. Due to these conditions, large inventories of supplies must be kept on hand, varying from a spring minimum of $45,000 to a peak of $110,000 early in November. The average cost of all freight brought in from steel during 1937 was $0.01 per pound.

Jan 1, 1938

By David J. Mack

A SURVEY and critical appraisal of published information about Young's modulus was originally made by the writer because of a complete lack of information about this very important quantity in works on mechanics, physical metallurgy, physics, and other sciences. It was felt that a comprehensive summary of such information about Young's modulus might be of general interest and may suggest new problems or lines of attack on other problems that involve E. Hence this paper has been prepared even though it is only a review, with no new ideas or experimental data. The references are only those used in assembling the paper. No attempt was made to compile a complete bibliography on the subject of Young's modulus. CALCULATION OF YOUNG'S MODULUS FROM THEORETICAL OR EMPIRICAL CONSIDERATIONS Many attempts have been made to compute E from theoretical considerations. The earliest calculations were probably those of Tomlenson (1883) and Southerland (1891), but Fessenden 41,42 made extensive calculations a few years later and arrived at the relationship: [2E = 78. 101 (_L V] where V is the atomic volume. In 1923, Peczalski,43 working from the same stand-point but with more information available on atomic structure, arrived at an identical relationship, which he expressed as: [E=B(m) 2] where B is a constant of value about 8 • 10 7, p is density and m is atomic weight; the atomic volume, of course, being m/p. Portevin44 immediately pointed out that while the equations of Fessenden and Peczalski were true of the common metals, they gave low values for the refractory metals with high moduli (Fig. I). He showed (Fig. 2) that much better concordance was obtained by means of an empirical equation of the form: [E _ KT'Vb] where K is a constant; T the absolute melting point; V, atomic volume, and a and b constants of value approximately I and 2 respectively. This constant K in the Portevin equation is not necessarily the same for all elements, as shown by Thompson.45 Other equations for E based upon theoretical considerations have been derived by Honda and Yamada49 and Lasareff. 50 The most recent calculations of elastic moduli based upon quantum mechanics are probably those of Fuchs.46-48 He extended the method of Wigner and Seitz for calculating the lattice energy and compressibility of monovalent metals and computed the elastic constants of lithium,

Jan 1, 1945

By Nikhil Dhawan, SHAILA MIR

The emerging problem of electronic waste has promoted the interest in exploring metal recovery from secondary sources under the umbrella of urban mining. This study presents the physical and chemical characterization of various components present in end-of-life laptops to help ascertain the sites of metallic values and develop sustainable and environment-friendly recycling. The recycling potential of a laptop is evaluated by sequential disassembly, separation, and characterization of components such as body (49.8 wt.%), printed circuit board (9.7 wt.%), hard disk drive (4.9 wt.%), and battery (12.4 wt.%). The printed circuit boards comprise metallic values, majorly copper (25 wt.%), tin (5.8 wt.%), and lead (3.1 wt.%). The precious metals (Au, Ag) with an economic advantage are abundantly present in electronic components such as integrated circuits, capacitors, resistors, and processors. Critical elements such as lithium, cobalt, and rare earth elements are detected in the discarded laptops' batteries and hard disk drives. The recycling potential representing the amount of material that can be recycled in various components, depending on the type, concentration, and purity, is determined in the range of 36–100%. On average, a unit laptop contains~ 386 g of Cu (14.45 wt. %), 49.73 g Co (1.86 wt. %), ~346 mg Ag, ~141.2 mg Au, ~650 mg of rare earth elements (Nd, Dy). This study presents a database for investigating integrated and economical recycling techniques from different components of a laptop, and an overall process flow is also proposed.

Jul 24, 2021

By R. E. Peterson

A reduction roasting/magnetic separation/flotation process for beneficiating oxidized taconite from the western Mesabi iron range in Minnesota was evaluated in a Bureau of Mines research program to insure an adequate supply of raw materials for future ironmaking and steelmaking needs. The research was performed on a sample containing 35.4 pct iron and representing a deposit of approximately 2 billion tons of raw materials. An average of 1,419 lb of oxidized taconite and 37 lb of lignite reluctant per hour were fed to a 35 -foot rotary kiln in which the iron oxides were converted to artificial magnetite. The kiln was heated with pulverized lignite and natural gas. Most of the dust collected from the kiln exhaust gas was pelletized and recycled to the kiln. Magnetic separation and cationic flotation of the roasted material in a 900-lb/hr pilot plant produced a concentrate analyzing 67.9 pct iron and 4.9 pct silica and containing 69.2 pct of the iron in the kiln feed.

Jan 1, 1981

By Rhual L. Guerguerian

MINING has been practised by mankind for over sixty centuries (1). In 1876, the "ball mill" was patented, and during the century that followed rotary grinding developed to the state where individual machines are treating tens of thousands of tons of ore per day. This paper gives a brief description of design practices prior to the availability of advanced facilities, followed by modern analytical design development at Dominion over the past ten years.

Jan 1, 1978

By Arthur Glance

MINE safety is of the utmost importance to all operators and most operations have a safety organization, or safety inspector, whose job it is to be continually on the alert to detect and correct the hazards of mine operation. Reports from the Bureau of Mines show that next to roof falls, gas presents the greatest hazard in mining. The Bureau of Mines Information Circular 6680 shows that 162 explosions occurred in the United States during the five-year period ending June 30, 1932. Deaths resulting from these explosions amounted to 984, with a great many disabled and disfigured. A fatality rate of 6.07 persons shows the ex¬treme severity of this hazard to the industry. Various mine appliance companies have put on the market instruments for methane detection, which record in direct percentages the amount of methane present in the atmosphere. Unfortunately, few mining companies are using these instruments, however. Those available include the Burrell methane detector, the Wolf, the Martienssen, the Mine Safety Appliance detector, and the Union Carbide Company methane detector, which last I have used extensively in making mine inspections.

Jan 1, 1936

By Michael E. Ameel

The vibrated beam method of installing a vertical barrier wall is one of the least applied techniques, yet given certain site conditions and constraints, it is a cost-effective and proven method of controlling lateral groundwater flows. A recent full-scale application of this technique demonstrated its usefulness at an active manufacturing facility located in Northern Wisconsin. At this site, a 3,233 foot long cutoff wall was keyed into an underlying bedrock, which was located an average of 40 feet below the ground surface. Using a slag cement-clay based slurry, a 1E-7 cm/sec or less, nominal 4-inch wide cut-off wall was constructed using the vibrated beam method. Challenges included working around an active manufacturing facility with minimal access to the work area; installing the wall through a very dense glacial till; minimizing soil excavation volumes of potentially impacted soil; and, working around and adjacent to numerous active utility lines without impacting the facility operations. At utility locations, the vibrated beam wall was supplemented with a jet grout panel wall, without the need to bypass or otherwise interrupt any of the plant?s utilities. Quality control consisted of the monitoring and measuring of slurry parameters, survey control, and real-time monitoring and documentation of all critical barrier wall installation parameters. A vibration monitoring plan was also implemented to measure vibrations at utilities and adjacent facility structures. Proper equipment selection, significant up-front planning and close coordination with the facility resulted in a safe and successful project. The work was completed ahead of schedule during the 2009 construction season.

Jan 1, 2010

By Karl J. C. Harries

"4.1. INTRODUCTIONThis chapter, although divided into four parts, deals with only two principal topics. The first briefly describes and discusses some common types of property interests and considerations relating to them and the second deals with entering upon privately owned lands and obtaining the consent to do so.It should be noted that the terms “mining rights” and “mineral rights” are used interchangeably. As so used, they include the right to exploit the minerals and dispose of them for the benefit of the owner/lessee. This is relatively common in common law jurisdictions. In some jurisdictions, the two terms have distinct meanings, with “mining rights” referring to the right to work or exploit the minerals and “mineral rights” referring to the minerals themselves.Finally, it must be mentioned that the comments in the Introduction and §§ 4.2., 4.3. and 4.4. are based primarily upon Ontario law and Ontario’s mining and real property systems of registration. They have been included for illustrative purposes.4.2. LICENCES, CLAIMS, AND LEASESIn most jurisdictions, there are several basic types of interests that can be obtained from the state for mining purposes and that are of interest to the explorationist, as opposed to the operator. Different jurisdictions will have variations of these and possibly some extra ones that will address special purposes or local concerns. In virtually every jurisdiction, privately owned property rights are obtained through negotiation between owner and acquiror.Exploration or prospecting licence. This licence grants to the holder the right to prospect over a large tract of land and the exclusive right to acquire mining claims within that tract for the term of the licence. Such licences are usually negotiated documents requiring a minimum expenditure during the first year (often secured by a deposit or surety bond) and minimum annual expenditures thereafter to continue the licence in force up to its full term. The term will rarely exceed four years. The number of claims permitted to be staked will be limited in some way, possibly as to a maximum aggregate area or a maximum number of claims per annum. It is normal for the holder to have to drop part of the licensed area each year, so that the area shrinks annually, although exploration expenditure requirements will usually increase.These types of licences are usually used by governments to encourage exploration of otherwise unattractive or remote areas, such as the far northern parts of some of Canada’s provinces. They do not grant any real property interest in the area for which they are issued, and they will be subject to any claims or property rights that exist in the area. They are contracts with the state that grant certain exclusive rights in return for commitments to carry out work. They may or may not be specifically authorized by statute."

Jan 1, 2003

By Laurel A. Powers

The Bureau of Mines process for recovering Ni and Co from low-grade domestic laterites uses a reduction roast followed by an ammonia, ammo-nium sulfate leach. This investigation examined the waste streams of the process for their potential environmental impact and focused on the laterite residue produced. The U.S. Environmental Protection Agency's extraction procedure (EP) toxicity tests and column leaching showed that leachable metal concentrations would be low enough so that the residue would not be considered a hazardous waste under present definitions. Under nonacid leaching conditions, about the same amount of metal was extracted from laterites as from their residues, and the leachates were similar to water samples from an undisturbed laterite deposit. Washing tests on the laterite residue showed that ammonia and ammonium sulfate concentrations were reduced according to equilibrium stage calculations, resulting in residues that would be acceptable for revegetation. With water washing only, the residue would not be considered a hazardous waste even though significant amounts of Ni and Co were absorbed from entrained leach solution onto the residue. Washing first with fresh leach solution and then with water prevented this absorption and thus improved the overall metal recovery.

Jan 1, 1983

By D. E. Larson

The U. S. Bureau of Mines has developed a image analysis methodology to correlate the energy consumed during the grinding of an ore to the mineral liberation achieved. Energy consumption values are obtained using a laboratory-scale ball mill equipped with a torque sensor, and an automated image analyzer is used to determine the liberation present in ground products. By combining liberation information with energy consumption data an appraisal can be made of the energy required to liberate the mineral(s) of interest. Results of tests performed on a complex sulfide material determined the effects of grind duration on the liberation achieved and the energy efficiency.

Jan 1, 1995

By W. R. Reed, S. Klima, J. Driscoll, T. W. Beck

"Tests were conducted to determine properties of 4 foam agents for their potential use in longwall mining dust control. Foam has been tried in underground mining in the past for dust control and is currently being reconsidered for use in underground coal longwall operations in order to help those operations comply with MSHA’s lower coal mine respirable dust standard (1.5 mg/m3). Foams were generated using two different methods. One method used compressed air and water pressure to generate foam, while the other method used a low pressure air generated by a blower and water pressure using a NIOSH developed foam generator. Foam property tests comprising of a bottle shake test, foam expansion ratio, and water drainage were used to classify foams. The bottle shake tests determined that the lowest concentration of foam agent to be used was approximately 1.5%. Compressed air generated foams tended to have low expansion ratios (10-19) with high water drainage. Blower air generated foams had higher foam expansion ratios (30-60) with lower water drainage. Foams produced within these ranges of expansion ratios are stable and potentially suitable for dust control. The different foam agents produce foams with different material properties. Results of testing eliminated two foam agents for future testing because they had poor expansion ratios. The remaining two foam agents, while having different foam properties, seem to have properties adequate for dust control. These material property tests can be used to classify foams for their potential use in longwall mining dust control. INTRODUCTION About one-half of U.S. underground coal is produced by longwall mining. This technique allows for mining high volumes of coal, producing significant amounts of coal mine dust. This can lead to the overexposures to longwall miners and possibly occupational respiratory diseases black lung and silicosis, which have no cure and can be disabling or fatal. The only method to avoid these occupational illnesses is through elimination of exposure to respirable coal mine dust and crystalline silica (quartz). The current occupational exposure limit for respirable coal mine dust is 1.5 mg/m3 during each shift that a miner is exposed in the active workings of the mine or in mine facilities [1]. When respirable quartz is present, the mine must maintain an average concentration at or below 0.1 mg/m3. If the mine exceeds the 0.1 mg/m3 respirable quartz dust concentration, then the applicable respirable dust standard is reduced, calculated as 10 divided by the percent quartz present [2]. Respirable dust samples collected by U.S. Mine Safety and Health Administration inspectors for the five-year period from 2010 to 2014 found that 5.6% (53 of 943 respirable coal mine dust samples) of the longwall operators on the tailgate side exceeded the coal mine dust standard, and 4.3% (76 of 1768 samples) of the jacksetters exceeded the standard. If silica is present, the reduced standard is implemented, meaning that 11.4% (36 of 316 respirable coal mine samples analyzed for dust) of the jacksetters exceeded the reduced standard. Only 3.8% (18 of 478 samples) of the longwall operators on the tailgate side exceeded the reduced standard [3]. Had the 1.5 mg/m3 standard been in effect during this period, non-compliant samples would have been much higher. For example, over 15% of the samples collected at the tailgate shearer operator occupation exceeded the lower standard."

Jan 1, 2017

By Oliver C. Ralston, and others

"INTRODUCTION Investigations of the Nonmetals Division are now conducted at College Park, Md.; Tuscaloosa. Ala.; Seattle, Wash.; and. Norris, Tenn. The last of these was acquired, this year by arrangement with the Tennessee Valley Authority and is engaged in electrothermel research, using power generated by the T.V.A. and. raw materials from that region. In general, the work of the division is concerned with dressing nonmetallic minerals end utilizing the products there-from. Coal, salts, and waters are investigated, and the suitability of apparatus and equipment is studied.As the Metallurgical. Division of the Bureau of Mines makes routine tests of certain nonmetallic ores under prescribed conditions for the public if they are of general interest, the published reports of that division should be read and thus, with the reports of tile Nonmetals Division, the whole field may be covered."

Oct 1, 1939

By Raymond B. Ladoo

Toward the end of 1920 , the average grades of ground feldspar offered to the pottery industry were so poor and so generally unsatisfactory that many of the largest consumers decided to take active steps for their own protection . A few of the potters made arrangements to grind their own feldspar , while others asked the Bureau of Mines to make a detailed study of the problem and to suggest methods of improvement . Accordingly such a study was undertaken, the partial results of which are outlined in this preliminary report . The outstanding features of the present feldspar industry which are of interest in this connection are stated below. (1 ) Many grinding companies do not own or control all or even a major part of their sources of crude material , but buy in job lots from many sources . (2 ) There is great need of more adequate engineering and chemical control over mines and mills . ( 3) ~ Out of date , inefficient methods and equipment for mining and grinding are in common use . (4) Little or no cooperation exists between feldspar producers , but on the contrary many feldspar companies are exceedingly secretive . This tends towards (a) preservation of obsolete methods ; ( b ) want of knowledge of the essential features of production , market requirements , and the relation between total milling and consuming capacities of the country; ( c ) inefficient and often mistaken trade practices ; ( d) unprofitable and even ruinous competition in dull periods . (5) The small size of many feldspar deposits precludes maintenance of an efficient organization at each individual mine . ( 6 ) Many of the best deposits of feldspar situated close to railroads are becoming depleted , which results in gradual lowering of grades , and increase in cost for better grades . (7) There is a lack of exact mowledge of the ceramic properties and behaviour of feldspar by some consumers , which results in ( a) purchase of feldspar on the basis of price alone , thus encouraging low production costs at the expense of quality , and ( b) inefficient and expensive cross- hauling of both crude and ground feldspar .

Jan 1, 1922

By Foster Bain

MOST of us householders in the East burn anthra-cite, so the problem that interests us most is the distribution and supply of the domestic sizes of anthracite. That, however, is only a small part of the coal problem and has its own peculiarities. Whether anthracite prices are high or low is largely a matter of relativity, depending on the size of the transaction, the available supply, and other things. As an isolated example which I hesitate to quote because it is not entirely representative, you may be interested to know that the Government fuel yard has been delivering to the Government buildings in the District of Columbia, white-ash stove coal at 16 c. a ton less during January, 1923, than during the same month of 1922. The reason is that the Government deals only with large companies who have been wise enough not to boost their prices and the small increase at the mine has been more than offset by the decrease in railroad rates. The total cost is $12.50 per ton, but I want to make it perfectly clear that it does not follow that this would be a just price for a retail dealer to charge the domestic consumer. For example, in the Government business there is no such thing as a bad debt, and certain other fixed or general charges are charged to other departments. The Bureau of Effi-ciency made an effort to determine what would be a. legitimate handling charge for a retail dealer, in Washington, and concluded that if the Government's cost of handling was $1.00, then $1.88 would be the corresponding fair charge to pay a retail dealer carrying the same volume of business, allowing for bad debts, complete depletion and depreciation of his equipment, and 10- per cent. profit. Assuming that this is the correct differential for Washington, it does not' follow that it would be equally just for Pittsburgh, New York, or elsewhere; nor does it by any means follow that it is a fair differential this year, because the dealer, after being unable to use his equipment in the summer months, now has to deliver an unusually large quantity of coal. I merely cite this instance to show that on the basis of primary cost of coal plus railway charges the retail price is not necessarily higher this-year than last.

Jan 4, 1923

By Gerald W. Elger

The Federal Bureau of Mines developed a modification in the conventional Kroll process for preparing high - purity hafnium metal . This modification involved the partial replacement of magnesium by sodium in the batch reduction of purified hafnium tetrachloride to sponge metal . The raw tetrachloride was purified either by thermal degassing of the volatile contaminants to the atmosphere or by fused- salt treatment . In the fused- salt treatment , the tetrachloride was contacted with molten alkali chlorides to remove the impurities . The reaction byproducts were removed from the metal by heat treatment in an evacuated furnace . The metal sponge was consolidated by melting into buttons or ingots , which were analyzed for impurities . The purity of the metal prepared by the modified process is superior to that of the metal produced by the conventional method . The hafnium metal was comparable to crystal - bar hafnium except for the oxygen content , despite the abnormally high impurity concentrations in the raw tetrachloride . Several ingots were successfully cold - rolled to sheet .

Jul 1, 1960

By M. E. Karabin, R. J. O'Malley

"A mathematical model of the roll casting process has been developed which predicts macro-variables, such as roll separating force, roll torque, and strip exit speed for a range of roll speeds. Continuum variables, such as interface pressure, interface shear stress, freeze-front shape, and internal temperature distribution are also predicted.The model consists of two independent segments: solidification and rolling. The solidification model is two-dimensional (thickness and rolling direction) and is capable of handling alloy solidification. The solidification model is employed until solidification through the thickness is complete, then the rolling solution is activated.The rolling model is a one-dimensional (rolling direction) mechanical solution based on the von Karman approach, coupled with a two-dimensional thermal solution. The flow stress is expressed as a function of the average through-thickness temperature of the strip.Experiments were performed using a laboratory roll caster to test and refine the model. Experimental strip exit temperatures were used as input to the model. Experimental and predicted roll torque and strip exit speea were forced into agreement at a single reference roll speed to obtain values for the coefficient of friction and the interfacial heat transfer coefficient. Using these values, good agreement was obtained between predicted and experimental torque and strip exit speed over the entire range of roll speeds examined."

Jan 1, 1986

By J. G. Phillips

Introduction Throughout the Great Plains region (the provinces of Manitoba, Saskatchewan, and Alberta), numerous clay deposits of widely varying composition and character are to be found. These may be classified into two general types: (1) surface clays, and (2) shales. The surface clays consist of a heterogeneous mantle of silts and clays interspersed with grave! and sand deposits, and may belong to any of the following groups: (1) lake clays: (2) river-terrace or flood-plain deposits; (3) delta deposits . In most cases, the water from which these deposits were ' laid down was derived from the melting ice of the continental glaciers. These surface clays, in general, possess certain characteristics in common, being all more or less calcareous, often silty, and showing a tendency to 'check' in air-drying. The shales found in this region are of Cretaceous and Tertiary age. These deposits have a wide extent, but there is frequently such a heavy covering of drift material that the clays are accessible chiefly along the walls of stream valleys, or along the escarpments of uplands.

Jan 1, 1929