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By Zara Hosseini

?Microseismicity ?Seismic Systems ?Intrinsically Safe and Explosion Proof Seismic System ?Case studies: ?Gas Drainage Optimization ?Fault Identification ?Conclusion Seismic Event ?Occurrences in which energy is released in the rockmass creating a series of seismic waves propagating throughout the rockmass ?Can cause a Fall of Ground or CoalBurst Factors creating Seismicity: ?Mining at Depth ?High stress zones ?Major geological structures ?Mining practices and strategies ?Mining activities i.e. drilling and blasting

Aug 1, 2013

By R. O. Neal, G. St. J. PERROIT

As natural gas is a waning resource in many places, increased interest has attached to the use of gas for the manufacture of carbon black. Because of a large number of requests for information on the subject, the Bureau of Mines has undertaken a detailed study of the carbon-black industry, covering the mechanical details of commercial methods, with the purpose of increasing the recovery of carbon black by such processes. A study has been undertaken of the economic factors governing the carbon-black industry, the uses and properties of carbon black, the dE)velopment of more Itccurate methods of testing carbon black, microscopic examination of different grades of black, physicochemical study of methods' of mQ.nufacture now in use, and research on new methods of manufacture. Part I of this paper covers the engineering and economic side of the industry; the other phases of the investigation which have been under the direction of G. St. J. Perrott, of the Pittsburgh station.of the United States Bureau of Mines, are discussed in Part II.

Jan 1, 1922

By Enrique Folcini

El presente texto señala el proceso de la industria siderúrgica en América Latina y el contexto económico en que se desarrolló. La industria siderúrgica se impulsó a partir de la última I guerra mundial, y desde 1950 ha cuadruplicado su producción, a pesar de que el producto bruto de los países apenas alcanzó a duplicarse. Para los próximos años, se espera que la producción mundial tenga una leve desaceleración a causa de la parcial sobrecapacidad de producción existente en los países más desarrollados; de form que contribuirá el conocido fenómeno de la decreciente elasticidad de los consumos siderúrgicos a sus mayores niveles de ingresos.

Sep 1, 1970

The Imperial Smelting Process (ISP) for the simultaneous smelting of zinc and lead was developed at Avonmouth from the 1930's with activity intensifying in the late 1940's/early 1950's. Present operations are based around the No.4 furnace which was built in 1967. Development during the 1980's has been driven by the need to sustain operations at low metals prices and has been aimed at reducing manning whilst increasing output. Although hit by several major plant disruptions, progress has been steady, culminating in a ú10 million capital programme in 1988?89 to upgrade the operation. The most important technical developments, reflecting the needs of the 1990's have, in the sintering area, included improvements to feed conditioning and sinter quality, a 20% uprate in production capacity by debottlenecking, and pilot work leading to the installation of a Boliden-Norzink mercury removal plant. In the smelting area the ISP furnace has been rebuilt, with a redesigned bottom section to eliminate earlier operating sensitivities, and to achieve higher blowing capability, and at the zinc refinery the columns have been rearranged for more flexible operation and higher capacity.

Jan 1, 1989

By May P. M

The role of chemical speciation in alkaline cyanide solutions is discussed by reference to recent experimental data from the authors' laboratories. It is shown that serious gaps exist in our present knowledge of the thermodynamics of cyanide complexes in solution. Nevertheless, using the available data and the JESS suite of computer programs it has been possible to develop a simplified chemical speciation model for alkaline cyanide solutions under conditions relevant to the gold extraction process. Some possible implications of the model for plant operations are Discussed.

Jan 1, 1991

By Higuchi K

Intorducing the hypothesis that the cause ,òi spontaneous combustion of coal is depending un the accumulation of heat produced by its oxidation, the authors derived the equation expressing the temperature change in a heap i fine coal. To solve the equation, thermal conductivity, specific heat and rate of heat ,eneration of fine coal (-48 mesh) were measured at various temperatures in the range _'0-65¦C. The equation was solved numerically and the volume of fine coal which would ignite spontaneously was estimated as the function of ambient temperature. Using 170 Kg of fine coal, everal experiments for confirmation were conducted. At the ambient temperatures of 60¦C nd 50¦C, coal began to fire spontaneously brut 00 and 110 hours later respectively. Iii addition to this, the measured t,,rp,i,itures in the coal heap agreed with the ,aLulated ones comparatively well, If more volume of fine coal were used, experi;:ontul ;,eneration of spontaneous combustion from ...,n-, , 1-1 I'd Sill al r..

Jan 1, 1981

By Zygmunt Sadowski

Problems encountered in barite flotation from various waste materials such as spent drilling muds are likely to be closely connected with the effect of chemical additives and metal ions present either added or present as contaminants, on the flotation. Fuerstenau and Palmer (1976) have studied in detail the adsorption of multivalent cations onto oxide and silicate minerals. It was observed that the adsorption of a multivalent metal species exhibits a sharp pH dependence which is related to the formation of hydroxy complexes of the metal ions in solution. Investigations on the recovery of barite from tailings ponds and mining wastes (Sullivan and Lamot, 1981) have shown that such barite materials can contain large quantities of carbonate and silicate minerals (including clay minerals). Also iron oxide slimes can be present. From these substances cations such as Ca2+, Mg2+, Fe2+ and A13+ can potentially dissolve and be present in the aqueous phase accompanying the various minerals. These ions and their hydrolysis products can have a substantial effect on any subsequent flotation scheme. The present study investigates the effect of the noted ions on both the stability and electrokinetic behavior of barite suspensions.

Jan 1, 1986

'T. C. MERRIMAN, New Haven, Conn. (written discussion *).-This most interesting paper gives much carefully obtained and valuable data. However, there are two points in connection with the commercial application of such data that might possibly be a source of trouble and mis-understanding. In the first place, the examination of thin sections of annealed brass, subjected to standard Brinell test.(500 kg. on a 10-mm. diameter ball) at thicknesses from 0.075 to 0.150 in. (1.9 to 3.8 mm.) indicates that cold work has been performed on the specimen during the application of the load sufficient to extend way through the section, and have the hardness of the metal affected by the backing. If the usual steel support is used, this effect is very evident. If a piece of soft brass is used as a support, there is an indentation in the surface of the support accompanied by a bulge on the under side of the tested specimen opposite the impression made by the 10-mm. ball. The result is that Brinell specifications (governmental or otherwise) on stock for a certain purpose may not be fair in all cases, since manufacturers, owing to differences in equipment, etc., may not all use precisely the thickness and conditions of stock on which the Brinell specifications were based. This would mean that the government Brinell specification might not give them the temper of stock best suited for their manufacturing methods. The concluding paragraph of this paper, stating that "the hardness of cartridge brass may be determined with greater accuracy by the Brinell hardness measurement than by attempting to judge it from the grain size" appears to be in line with the movement of the last year or so among brass manufacturers toward substitution of the Brinell test for microscopic examination as an acceptance test on cartridge brass. The statement may he strictly true that the Brinell test is the best test for hardness, but it is not, as the statement might readily be construed, a sufficient test of suitable condition. For instance, some cartridge brass might accidentally have been overheated to a point where it would be distinctly unsafe to use for the manufacture of small arms cases and then be so rolled (reduction 3 to 5 per cent.) as to pass perfectly proper Brinell specifications. Under such conditions the microscope would reveal its unsuitability where the Brinell test had failed so to do.

Jan 4, 1919

By B. C. Alberts

Planning the use of South Africa's energy resources, especially coal, is of the utmost importance. The State and the mining industry require reliable official estimates of the economically mineable coal reserves for planning purposes. An overview of al the previous reserve estimates is given, with specific attention to the two most recent estimates-those of Petrick and De Jager. The differences between these two estimates are highlighted. The following important aspects are discussed: . the need to update the information regarding South Africa's mineable coal reserves, . the necessity of understanding and agreement between the coal-mining industry and the State department responsible for updating the coal-reserve data, and . the importance of the specific assumptions used in the updating of the data. A downward adjustment of mineable reserve figures is proposed, and the factors that influence the meaningful exploitation of the coal reserves are discussed. A recommendation is made as to how the Waterberg coal reserve should be exploited, and it is concluded that the Soutpansberg Coalfield cannot be exploited economically in the foreseeable future. An evaluation of the status of the coal-export trade is made and compared with the assumptions and targets set at the start of the coal-exportation scheme. The comparison shows the extent to which the exploitation of the coal reserves is being negatively influenced by the current market situation. Recommendations are made regarding planning for the coal-export market, and the aspects that have to be taken into account to keep South Africa in the export market are identified. Reference is made to the fact that the present unrestrained wage and salary adjustments, which show a total disregard of South Africa's poor productivity record, require serious thought and speedy rectification if the country is to survive in the export market. A salary and wage strategy must be developed to suit the specific needs of the Republic of South Africa.

Jan 1, 1987

By Wern-Ping Nick Chen

Durability risks for underground facilities can be underestimated during design phase as compared to well-known geological risks. However, unclear durability requirements can result in construction schedule delay and change orders. Unlike bridges or buildings, a unified underground durability code or standard does not exist. This paper will provide a durability approach for underground facilities, including degradation modes, mitigations, and compliance measures during construction. In addition, this paper will address how to clearly specify durability requirements in a contract document to reduce disputes during construction and discuss key durability tests that are time consuming and will impact construction schedule if not timely planned.

Jun 23, 2024

By Donald H. Mullen, Walter R. Storms

"INTRODUCTION The Copper Flat area of the Central mining district, Grant County, N. Mex., has been visited by numerous engineers 4/ of the Bureau of Mines and geologists 5/ of the Federal Geological Survey. In December 1944 the Bureau. 6/ proposed that geophysical work be done in that area in order to locate favorable sites for future company exploratory and development work. This geo-physical work was begun early in 1945 but never fully completed because of insufficient funds. The engineers who made the survey recommended that more work be done, especially to locate the bottom of the Copper Flat laccolith by resistivity-depth surveys. All known minable zinc-lead ore bodies had been found above this laccolith in the Copper Flat mine, but it was thought that other minable ore deposits should occur in favorable limestones beneath it. The geophysicists also recommended core drilling beneath the laccolith.In the summer of 1946, following some mapping by S. G. Lasky of the Federal Geological Survey, funds were appropriated for a Bureau of Mines project in the Copper Flat area. The project was completed in June 1947. 8/"

Apr 1, 1948

By Otto H. Henry, J. J. Cordiano

THOUGH powder metallurgy is one of the oldest of metallurgical processes, it is in its infancy as a branch of the modern field of metallurgy. As early as 3000 B.C., the ancients produced implements and weapons of iron by reducing iron ore in a charcoal fire and forging the resultant sponge while still hot into the desired shape. Melting and casting soon superseded the powder metallurgy practice, and it was not until the turn of the twentieth century that powder metallurgy was applied to the commercial manufacture of tungsten lamp filaments. From this beginning, the use of the powder metallurgy process spread to the manufacture of porous oil-impregnated bearings, cemented carbide tools, contact points, diamond grinding wheels, clutch facings, starter brushes, resin-bonded radio cores, magnets, metallic filters, and other parts. More recently, and particularly during the present war, there has been a definite trend toward the manufacture of machine parts by this process in competition with the more conventional fabricating methods. Notwithstanding these many developments, scientific progress has been slow. While many articles on powder metallurgy have appeared in the press and various publications, there have been too few contributions to our technical societies, with the result that there is a dearth of the type of information necessary for the full development of this science. It is of primary importance that the results of research and development be freely disseminated if powder metallurgy is to realize its fullest potentialities. PURPOSE OF INVESTIGATION Excluding the refractory metal field, all commercial powder metallurgical products made by a cold compressing and sintering operation contain voids. These voids can be substantially eliminated by subsequent severe working and heat-treatment, but such practice has not proved economical in most applications. By applying heat during the compressing operation, plastic deformation of the powder particles is substantially increased, and the resultant compact or briquette is practically free of voids. However, hot-pressing has many attendant problems, which at present preclude its use in the manufacture of precision parts. The more important of these are to devise: I. A die steel capable of withstanding high pressures at elevated temperatures. 2. A high-temperature lubricant capable of preventing excessive die wear and welding of the compact to the die walls. 3. A method of retaining a neutral or reducing atmosphere in the compacting zone of the die assembly. 4. A means of ejecting the hot-pressed specimen into a neutral atmosphere until reasonably cold.

Jan 1, 1945

By W. P. Haynes

To evaluate the potential use of battery-powered vehicles, the Bureau of Mines studied the performance of a battery-powered truck propelled by a 9.6 kw dc motor in considerable detail under various driving conditions. Some of the factors investigated were: Gear ratios, payload (1,468 lb maximum), road grade, stops made per mile, and charging time. With the exception of some difficulty with brush wear, operation and maintenance of the truck was generally trouble-free. On range tests carrying an 868-lb payload a distance of about 50 miles at an average speed of about 19 mph in normal driving, the Bureau's battery-powered truck averaged 1.6 to 1.9 miles per ac kwhr input. Stop-and-go tests indicated that prospects for the use of battery-powered trucks in house delivery service within city limits are good; performance of the Bureau truck was sufficiently high for that type of service. The estimated power cost of 2.65 cents per mile while making 10 stops per mile was attractively low from the standpoint of fuel costs.

Jan 1, 1967

By F. C. Robles Hernandez

This paper presents the results of the electromagnetic semi-solid treatment of the 319 aluminum foundry alloy, Various levels of structure modification were achieved controlling the AC current used to create the Electromagnetic Field, thus manipulating the intensity of the field, The level of grain refinement, partial modification of the Al-Si eutectic, as well as cellular dendrites were observed, A quantitative analysis of the structure was performed using Image Analysis (IA) techniques. In addition a novel Thermal Analysis methodology was developed for the on-line determination of the microstructure modification level.

Jan 1, 2004

By J. H. Holden, C. C. Shale, G. R. Strimbeck, W. S. Bowie

Electrical characteristics are presented for air in a 2 - inch pipe - type electrostatic precipitator operating under dynamic conditions at temperatures of 600 ° to 1,500 ° F and pressures of 0 to 80 psig using a negative discharge electrode . Results of this one - geometry study show that current - voltage relationships are a function of air pressure and temperature and indicate that precipitators can be used at any temperature through about 1,350 ° F over the full range of pressure . Corona starting voltage and sparkover voltage vary directly with pressure and inversely with temperature . At temperatures above 1,350 ° F use of precipitators may be limited to operations at pressures somewhat above atmospheric pressure . Theoretical derivations are presented that relate the effect of gas density on corona starting voltage and the effect of ion mobility on corona current . Deviation from the theory is noted at high current levels . Theoretical discussion is presented to explain the apparent electrical limitations for use of precipitators at high temperature , low gas density , and high corona currents , conditions at which calculated ionic velocities are extremely high . Experimental results are interpreted in terms of the theory presented . 1,500 ° F thermal ionization does not appear to be a critical factor .

Jan 1, 1963

By T. W. Wlodek

"AbstractIn this paper a new type of durable 'spiral-rolled' drill set is introduced and its performance discussed. Efficient and economical mine drilling-depends to a great extent on durability of the drill-set employed. Premature failure of this element damages the drill bit and is costly when tungsten carbide bits are used.Time of drilling of 'spiral-rolled' drill sets introduced at present in Canada is considerably larger than for the presently used drill steel, but laboratory simulated service tests and practical field tests show that the 'drilling life' of the spiral-rolled drill set is several times that of ordinary drill steel.Some features of differential plastic deformation and differential surface rolling, so called 'spiral-rolling', are given.Relations between the drilling machine drill set and characteristics of the ore are discussed. The effect of shims on conical drill rod attachments, the mechanism of failure of drill steel, .and stresses during mine drilling, are analysed.IntroductionIN MINE DRILLING operations, the main interests are: the drilling machines as a source of working energy, the drill set as the tool transferring the working energy to the cutting edges of the bit, and, finally, the drilling characteristic of the .ore or waste rock.This paper includes a review of the possibilities of metallurgical and mechanical improvements in the drill set, with particular attention to drill steel and the attachments.For economical and efficient mine drilling operations, a durable drill rod, attachment, and drill bit are essential. Premature failure of any of these parts interferes with mining operations and is costly."

Jan 1, 1955

By J. J. Rutledge

I. DESCRIPTION OF THE CLINTON ORES AND ASSOCIATED POCKS. THE Clinton rocks in Stone Valley comprise (1) thick layers of deep-red shale, (2) layers of reddish-gray shale interspersed with beds of sandstone and thin beds of extremely fossiliferous limestone, and (3) yellowish-gray shales alternating with thin layers of olive-colored shales. These layers of shale are all very thin and are at no point massive.1 A bed of gray-white sandstone varying in thickness from 12 to 30 ft. occurs in the tipper portions of the Clinton shales. This is called the ore sandstone, a name given to it by Rogers and adopted also by the Second Pennsylvania Geological Survey. It is the surest guide to the presence of the iron-ore bed, which lies below its lower edges at distances varying from 10 to 20 ft. This ore sandstone, in the valley, lies generally at very low inclinations, but often is locally subjected to considerable changes in dip. At its outcrop this ore sandstone weathers very easily and yields a rather sparse crop of stone, Composed of dirty, iron-stained boulders. Upon the roads these boulders are quite well rounded, and bear fragments of crinoid stems and other fossil forms. The ore sandstone exhibits at many points evidences of former movements in this very great thickness of the shales, and as it is the only stratum in this series competent to transmit and record stresses due to structural movements, its evidence is of considerable importance in determining the occurrence of movements in times past.

Nov 1, 1908

The research, development and testing of a Blast Control Plug (U.S. Pat. #4,754,705) funded by the U.S. Department of Energy is described. The plug's function is to improve blasting efficiency through the enhancement of stemming effectiveness and thereby reduce drilling and blasting costs. The plug comprises a solid unit placed in the blast hole within the stemming column above the explosive. It is designed for use with back filled drill cuttings or any other suitable material The research and development program comprised the testing of the plug in small diameter holes in competent rock for both bench and crater blasting configurations and full scale field trials in multiple hole and row blasts using blast holes of from 76 to 387 mm in diameter. Test measurements included stemming displacement and velocity, face movement and extent, peak air over pressure and ground surface peak particle velocity. Data acquisition equipment included a Spin Physics SP2000 high speed video motion analysis system, and acoustic and seismic monitoring units. Substantial reductions in stemming ejection velocity or ejection elimination were achieved whilst reducing stemming length by up to 35% over conventional practice. Peak air blast pressures were also reduced by between 8 and 25 dB. A strong inverse relationship between rock face movement and stemming ejection velocity was found. The implications of the importance of stemming effectiveness in blasting and computer blast simulation is also addressed.

Jan 1, 1990

By V. Sheikhzadeh, S. M. H. Haddad, M. Saghaeian, N. Esmaeili, R. Hejazi

One of the most significant features of iron ore concentrate (pelletising feed) is the specific surface area (SSA) that affects the achievement of desirable pellet properties. There are various methods to determine this parameters and currently, the most common is the Blaine air permeability method. However, due to the simplified assumptions including spherical and identical particles and 50% bed porosity, the Blain test does not provide accurate results. In fact, these two suppositions are far from reality. In this research, comparison of SSA measurement ways are investigated, containing laser diffraction testing and Blaine air permeability, on samples with different SSA, obtained from Ball mill and high pressure grinding rolls (HPGR). The output data showed that the calculated amounts of SSA by means of laser analysis were far greater than any other one. Furthermore, in the same results of Blaine air permeability tests on samples comminuted by different grinding methods, it was observed that the SSA figures from the laser diffraction method for HPGR products were almost 800 units greater than Ball mill ones. Keywords: Pelletising feed, specific surface area, Blaine air permeability, laser diffraction testing

Jan 1, 2020

By Charles D. Borror, George K. Foster

The Jeffrey mine of the Canadian Johns-Manville Co., Limited, is in the town of Asbestos, situated approximately 100 miles northeast of Montreal and about the same distance southwest of Quebec, in Richmond County, Quebec. Mining operations were started in 1881 on outcrops on a hill, as a side-hill cut, followed by a second and third cut. This development was the forerunner of the present large open-pit operations, the mine now ranking as the largest open-pit asbestos mine in the world. Operations were first carried on by hand, then by horsepower and later by stem cableways. By 1924 the derrick spans, 2000 ft. or more long, became unwieldy. To overcome this, and also to eliminate hand labor as much as possible, steam shovels and railroad haulage were introduced. The steam shovels were replaced in 1928 by larger electric shovels of the full-revolving type. The Ore Body The ore body is a serpentinized peri-dotite rock mass. The chrysotile fibers form a network of veins throughout, varying from microscopic width to two or more inches measured across the veins (Fig. I). These veins may be continuous for a few or many feet; they may increase or decrease in width within a few feet. The veins in which the fibers occur per- pendicular to the veins are known as cross fiber. Those in which the fibers lay parallel to the veins are known as slip fiber. The cross fibers are of better quality, and more in demand. The majority of the fiber

Jan 1, 1948