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By J. Fred, Johnson

THIS TALK is a digest of some of the information contained in tables, one on practices and one on costs of shaft sinking, in Bulletin 357 of the U. S. Bureau of Mines written by E. D. Gardner, Supervising Engineer of the Bureau at Tucson, and myself. The table of practices contains information on 43 shafts and the table of costs contains information on 25 shafts. These various shafts were sunk between 1917 and 1930 so they may be termed modern practice with costs applicable in the United States, Canada and Mexico. In the compilation of this material the statistics on shafts which were concreted have been eliminated, as these figures were entirely out of line with corresponding figures for timbered shafts. It is my experience that where costs are divided between sinking and concreting the tendency is to load the costs onto the larger item of concreting. Thus a shifting of costs making an addition of 10 per cent in concreting costs may suffice to make a deduction of 40 per cent in sinking costs. Fine work is done (on the books) and everybody is happy. Most shafts are sunk with three shifts of men per day. Each shift consists of men who are miners, muckers, or timbermen, as chance may call for during their shift. Where pumping or high fixed costs do not necessitate three shifts it is cheaper to sink on two shifts. It is desirable for speed and economy in any case to work out a cycle of operations for each 24 hours. In this way men are hired for their ability as machinemen, muckers, or timbermen; they know exactly what to do and there is no passing the buck to the next shift.

Jan 1, 1933

By Kis M

The purpose of seismic control of blasting is to indicate the vibration magnitude or to eliminate the occurrence of vibration damage caused by blasting. At the Mining Research Institute in Hungary, a new method has been developed to determine the method of delay. Near the blasting site (within 100-200 meters), the peak value of the particle velocity is determined by calculation and also by measurement. In the calculations, the time error of the electric detonators is taken into consideration. During the test program, the results of the experimental blasts and the calculated data have shown good correlation. The method of calculation helps the operator eliminate vibration damage, while the greatest quantity of charge can be detonated.

Jan 1, 1979

By J. C. Haptonstall

The Bismark Mine is located in northern Chihuahua, Mexico, 150 km (95 miles) southwest of Ciudad Juarez (Fig.1). The ore deposit was discovered in 1979 and was placed in production in 1992. The production rate is about 2.4 kt/d (2650 stpd) from an ore reserve of 8.5 Mt (9.3 million st). Grades currently average about 8% zinc, 0.5% lead, 0.2% copper and 50 g/t (1.46 oz/st) silver. Substantial inflows of water into the underground mine complicate the operation. Complex metallurgy poses another challenge for the operators. Bismark is a joint venture with 90% participation by Minas Penoles, SA de CR of Mexico City and 10% participation by Promociones Industriales Banamex, S A de C V (PIB S A) of Mexico City. Anew company, Minera Bismark, SA de CV was formed to operate the property. Cyprus Minerals was a 40% participant in the joint venture but, in early 1993, sold its share to Minas Penoles. The Bismark Mine is one of the largest new underground mining projects built in Mexico during the last 10 years. It is the country's fifth largest underground metal mine and provides about 1 % of the world's zinc supply at about 50 t/a (55,000 stpy). Bismark is a trackless operation with overall productivities of 7.6 t/manshift (8.4 st/manshift). The 2.4-kt/d (2650-stpd) concentrator started up in March 1992.

Jan 1, 1994

By P. Payson

Intergranular corrosion in corrosion-resistant chromium-nickel steels has been widely discussed in the last few years. So far as the author knows, nothing has been published which definitely shows that this tendency can be eliminated, although suggestions have been made that a remedy is possible if certain specifications are satisfied. Strauss, Schottky and Hinnüberl suggested an increase in chromium content to an extent that would prevent the impoverishment of chromium on carbide precipitation sufficient to cause impaired corrosion resistance in the matrix. Pilling2 suggested an increase in nickel, so that the stability of the austenite matrix would be increased. Aborn and Bain3 say that "intergranular attack—may be eliminated by preventing carbide precipitation (e. g., by lowering the carbon content or somehow raising its solubility) or by precipitating it permanently under conditions which will not remove chromium from solid solution so drastically at any points." In a later paper Aborn and Bain4 state that many different metallic elements, tungsten, vanadium, copper, aluminum, molybdenum, titanium and zirconium, have been added in small percentages to increase the stability of these alloys, but that it has been reported that according to the copper sulfate test these added elements act only to retard the intergranular corrosion. and that increased nickel and chromium contents have similar effects. Newell5 showed that the lower the quenching temperature before reheating, the less severe was the intergranular attack.

Jan 1, 1932

By B. Anameric, S. K. Kawatra

Pig iron nuggets were produced in a laboratory scale furnace at Michigan Technological University. These nuggets are produced from pellets consisting of a mixture of iron oxide, coal, flux, and a binder, which are heated to 1450°C.These pellets then self-reduce to produce a solid, high-density, highly metallized (96.5% Fe) pig iron. During the nugget production process, a separate slag phase forms that cleanly separates from the metal. The physical and chemical properties of the pig iron nuggets are similar to pig iron produced by blast furnaces, which is distinct from Direct Reduced Iron (DRI).

Jan 1, 2004

By James R. Wait

It is the purpose of this paper to review theoretical model concepts in through- the -earth transmission of electromagnetic waves. While the subject is very broad in its defined scope, we will be conscious of the specific applications to mine rescue and emergency telecommunications in coal mine environments. The plan of the paper is to outline previous theoretical efforts without attempting to attach names or organizations to the specific developments. However, we include a guide to the literature as an appendix. Without pretending to be entirely impartial we include a critique of the limitations of the available analytical models. As I see it the central problem is to calculate the steady state mutual impedance of a four-terminal network that is the black box characterizing the through-the-earth path. Problems of secondary importance include the determination of the input impedances of the two pairs of terminals and the associated transient responses. [ ]

Jan 1, 1973

By Richard F. Link

The objective of this report is to explain a statistical method for the summarization, organization, and classification of multivariate assay and other data from the mineral industry. Multivariate data are those characterized by several measurements at each data point, such as assay data from a mixed metal mine, or blast furnace data. A specific method of linear discriminant analysis, the Mahalanobis d2 procedure, is explained, starting from elementary principles; the d2 procedure enables many measurements at many data points to be studied by investigating the interrelationships among the data. The relation of linear discriminant analysis to other statistical methods for treating multivariate data, in particular the eigenvalue technique of factor analysis, is also explained. Example analyses are made on data from the Frisco mine, San Francisco del Oro, Chihuahua, Mexico. The data comprise assay values for silver, lead, copper, and zinc taken at some 19,000 sample points distributed into 91 groups.

Jan 1, 1967

By Pablo Bifant

El presente texto describe el proceso de las exportaciones chilenas en el mercado, características, determinación del precio, el mercado mundial de mineral como mercado "cautivo", producción y consumo mundial y la importancia del avance tecnológico.

Jul 1, 1964

By Victor Martín Salinas Chacón

"El presente trabajo describe el desarrollo de un Programa de Entrenamiento Basado en Computador para una Planta de Electrorefinación aplicado a trabajadores de 8 especialidades, donde se previene errores en ladirección del aprendizaje y se disminuye el tiempo de entrenamiento en la transferencia del conocimiento. El programa comprende el desarrollo de módulos de entrenamiento para el personal de operaciones y mantenimiento y utiliza el sistema CTS permite que los alumnos con conocimiento parcial del proceso seleccionen los temas de su interés. Para la elaboración de los descriptores de contenidos de dichos módulos, se realiza un análisis de los estándares de competencia, considerando el aporte de las jefaturas de cada especialidad y el levantamiento de información en visitas a terreno."

Sep 14, 2009

To predict the spontaneous combustion potential of bituminous coals using a simple expression based on an easily acquired coal property. Background Approximately 20% of underground coal mine fires in the United States since 1978 have been attributed to spontaneous combustion. Spontaneous combustion fires in underground mines are most likely to occur in gob area; and are difficult to detect and to extinguish by direct fire fighting methods. Often, sections of the mine or the entire mine must be sealed for long periods, at a great economic loss to the mine operator, mine employees, and the surrounding community. It is conservatively estimated that the cost of scaling a large mine is about $50 million.

Jan 1, 1989

By Joseph W. Mussey

Bio-epigenetic sulphur deposits occur in Pecos, Reeves and Culberson Counties of far West Texas. Sulfate reducrng bacteria, utilizing hydrocarbons as energy, transformed gypsum into replacement limestone and hydrogen sulfide. Hydrogen sulfide, retained in the porosities of the replacement limestone, was subsequently oxidized by highly oxygenated groundwaters, and native sulphur precipitated. West Texas sulphur was first recognized at surface exposures by William P. Blake, a geologist attached to the Captain Pope Military/ Scientific Expedition of 1854. Attempts were made in the early 1900's to mine these sulphur vent exposures by a retort method, but the ventures met with little success. In 1967, Duval discovered a large sulphur deposit near some of the old sulphur works in Culberson County. Duval also extended a small sulphur deposit in Pecos County. The Frasch process, developed for producing sulphur from Gulf Coast salt domes, proved successful in West Texas type sulphur deposits also. However, modifications of the process were necessary to provide economical and efficient sulphur recovery from the varied ore modes. West Texas conditions and logistics require the ultimate in productivity to be competitive in the domestic and foreign sulphur markets. Several companies, in addition to Duval, are producing or have produced sulphur in West Texas. As of the first of June 1984, a total of 29.4 million long tons of sulphur had been produced west of the Pecos -aver. Duval produced more than 88 percent of that total.

Jan 1, 1984

By A. C. Richardson

Troughs or launders are probably the oldest machines used for ore concentration, and their development was suggested no doubt by the natural segregation and stratification of materials that take place in the bed of a stream. Trough washers for coal cleaning were first used in France and Germany about one hundred years ago and have been used in some form or other ever since. The early launders were intermittent or batch machines, and only comparatively recent developments have made them continuous. The chief disadvantage of early launder systems as applied to coal has been that when a satisfactorily clean coal was produced the loss of good coal in the refuse was excessive. Other disadvantages have been the large quantities of water and the great lengths of troughs necessary to treat moderate tonnages of feed. One of the most widely used types of trough washers is the Rheolaveur, which has been developed in the last 25 years. Fig. 1 shows a more or less standard arrangement for fine coal. In this there are four trouglis placed one below the other and sloped a few degrees from the horizontal. Rheo-boxes or draws are provided at intervals in the bottom of the trough for the removal of material deposited from the stream. These draws are spaced substantial distances apart. Some of the rheo-boxes are provided with upward currents of water to modify the horizontal current stratification. In operation it is the function of the first two troughs to remove all refuse material and permit only clean coal to be discharged over the end. In order to accomplish this, large quantities of coal are drawn through the rheo-boxes. The third and fourth troughs are used to recover the coal discharged through the boxes of the first two troughs as a middling product and to discharge a clean refuse. The middlings are returned to the first launder and are usually about equal to 40 per cent of the raw coal being fed to the launder. In considering launder processes, one would reason that the conditions of extreme crowding under which stratification takes place in a flowing stream should effect complete separation in a single pass down a launder.

Jan 1, 1938

By Peijian Zhang, Yansheng Liu, Yuusaku Tominaga

The directions for ventilation control are often given in linguistic styles such as "if the airflow rate measured is small, a high value of rotation on a local fan should be chosen." In order to control the underground climate using a computer instead of a human being, both the reliability of data values measured underground and the application of human recognition of data values are required. The efficiency of data transmission is dependent on a method of checking a signal which is changed by mixing noises resulting from cases of electrical and mechanical damage to cables. In the study, fuzzy reasoning is adopted to choose a checking method for underground conditions from a normally operating state to an emergency. Fuzzy reasoning is applied to control airflow rate under the linguistic control rules given. It is shown that an effective series of linguistic control rules derived by fuzzy-sets theory is available in ventilation control when used in conjunction with an air velocity sensor, a computer and a local fan with thyristor control. Moreover, a system to make an optimum series of linguistic control rules for ventilation control is introduced.

Jan 1, 1987

By G. Abowitz, R. B. Gordon

The velocity of sound, mass density, and thermal expansion coefficient were measured in dilute lead, tin, zinc, bismuth, cadmium, indium, and potassium amalgams as a function of composition. Measurements in the Hg-TI system extended ovev the wider range of composition, 0 to 40 at. pct TI. The sonic velocity was measured as a function of temperature. The calculuted adiabatic compressibility in all cases was found to decrease much more rapidly than would be expected on the basis of a linear variation with composition. An interpretation of the results is given in terms of changes in the Debye characteris -tic temperature of mercury on alloying and a possible change in the bonding of mercury itself. If a liquid is considered as an isotropic elastic medium, the phase velocity of a longitudinal elastic wave traveling in the liquid is given by where K is the bulk modulus, G the shear modulus, and d the mass density. G can be neglected for liquids of ordinary viscosity, i.e., approximately 1CT2 poise, because the shear stress component is relaxed essentially at once. That is, for liquids of ordinary viscosity and at frequencies of the applied stress up to several hundred megacycles, the relaxation time of the shearing process is much shorter than the period of the applied stress. Eq. [I] then reduces to The adiabatic rather than the isothermal compressibility is measured at the megacycle frequencies used in ordinary ultrasonic velocity measurements. The sonic velocity and compressibility have been determined for many organic liquids and aqueous eletroltes,' and the results have been interpreted in terms of existing theories for these fluids. The velocity of sound and compressibility are important parameters in theories of the liquid state. For example, equations of state have been proposed relating the free volume of liquids to the acoustic velocity.3 Comparatively very little work has been done on the acoustic properties of liquid metals and alloys. leppa,' orddon, and several other investigators

Jan 1, 1963

By Fred N. Kissell

This U.S. Bureau of Mines report is a guide for the control of air contaminants during tunnel construction. Topics discussed are calculating air quantity requirements, types of ventilation systems, planning ventilation systems, control of methane gas, control of dust, control of diesel emission, ventilation to remove blasting fumes, measuring airflow, and measuring gases. This report does not provide detailed design information, but seeks to answer practical questions on air contamination issues.

Jan 1, 1995

By S. Banisi, J. A. Finch, A. R. Laplante

"A technique for on-line simultaneous estimation of gas and solids holdup (volume fraction), based on a combination of conductivity and pressure difference measurements, is proposed and tested in a laboratory flotation column (10cm in diameter and 447cm in height). Fundamental concepts underlying this technique and the effect of relevant parameters are discussed. In the studied range, 3-30 %v/v gas holdup and 2-18 % v/v solids holdup, experimental results showed good agreement between the estimated and actual holdup values (as determined by an isolating technique). The relative accuracy of the solids holdup estimation increased when solids density or solids concentration increased. Frequent re-calibration of pressure transducers was found necessary for accurate phase holdup estimation.IntroductionGas holdup is a key parameter in controlling the performance of flotation columns. For example, flotation rate is affected by bubble size and gas rate both of which, in turn, affect gas holdup. Moreover, gas holdup also determines the slurry residence time which indicates a direct influence of gas holdup on recovery.Gas holdup determination has been the focus of many studies (e.g., Castillejos, 1986; Marchese et al., 1992). Some of the techniques which have been used are given in Table 1."

Jan 1, 1994

By Dan Zou, Ji Chen, Deqian Li

"Bayan Obo mixed RE concentrate is the largest RE source in the world. RE elements occur dominantly in bastnaesite and monazite. This paper describes a clean and green technique for processing Bayan Obo mixed rare earth (RE) concentrate. A two-step oxidation method can lead to the effective recovery of REs, thorium (Th), fluorine (F) and phosphorus (P). Ce has a property of valency change, enabling the separation of it from other RE(III) elements. Making use of the interactions of cerium (IV) (Ce(IV)), F and P, a new extraction system was created to separate Ce(IV) effectively from other RE(III) while recovering F, P and Th by complexing F and P following the oxidation of Ce(III) to Ce(IV). The method includes two parts. Firstly, bastnaesite is oxidized by air roasting and sulfuric acid leaching. And then a first leach liquor containing Ce(IV), F and P is obtained. Secondly, monazite was converted into REhydroxide through alkaline attack and then Ce(III) in the RE-hydroxide was oxidized into Ce(IV) by wetair oxidation. After sulfuric acid leaching the oxidized RE-hydroxide, a second leach liquor is obtained. The two parts of leach liquor containing Ce(IV), F and P are then extracted by Cyanex923 to obtain CeO2, CeF3 and CePO4 based on the complex of Ce(IV) with F and P. The raffinate was further extracted by the primary amine N1923, and Th-product was recovered as ThO2. The RE elements recovery yield during the whole process is greater than 92%. The new technique not only provides a new way for Bayan Obo RE ore utilization, but also avoids resource waste and environment pollution.INTRODUCTIONRare Earths (REs) refer to lanthanides, including scandium and yttrium. Owing to the similar structure and property of RE(III), it is difficult to separate them from each other, especially for the adjacent elements. According to the United States Geological Survey, in 2010, the whole world has about 142 million tonnes of rare earth reserves. In that, China ranks the second with 22% following Brazil which ranks first with 32% (Cheng, 2011). There are three main RE ore types in China with about 80% mixed ores in Bayan Obo, 10% bastnaesite ores in SiChuan and ShanDong province and 2.9% ion adsorption ores in Southern China. Bayan Obo mixed RE concentrate consists of bastnaesite and monazite. The concentrate contains CeO2/_REO of 50% and there are 7–8% F, 4-6% P and 0.2–0.3% Th."

Jan 1, 2016

By F. S. Hoseinian, M. Irannajad, M. Safari

In this study, the effect of chemical interactions of materials used in ion flotation on the removal of Ni(II) ions from low concentration synthetic wastewater was studied. Sodium dodecyl sulfate (SDS) and ethylhexadecyldimethylammonium bromide (EHDABr) as collectors and methyl isobutyl carbonyl (MIBC) and Dowfroth250 as frothers were used. To investigate the effective parameters and interactions of them, 16 experiments including 6 level variables were performed by supporting DX7 software and on the bases of 2-level factorial method. In the first step, the tests were conducted in a Hallimond tube. The result showed that collector of SDS and frother of Dowfroth 250 had appropriate interaction with each other at pH = 3. In the second step, optimal results from the first step were evaluated in a mechanical flotation cell. The removal of Ni(II) ions increased by increasing the time of flotation and they have a direct relation with the water removal. The kinetics study shows that the order and the rate of removal of the reaction do not follow any of the zero-order, first-order and second-order equations. The flotation rate curve on the removal of Ni(II) ions will divide the separation process to two stages, a fast flotation rate at the first stage and a slow flotation rate at the second stage. Ni(II) ions removal was obtained 88% at the best condition.This study showed that the use of ion flotation was a very effective method for Ni(II) ion removal from industrial wastewaters.

Jan 1, 2016

By Jon C. Volkwein

Advances in mining technology have enabled deeper seams of coal to be mined from the surface. Highwall mining is frequently used to mine areas at the perimeters of a surface mine when removal of the overburden becomes uneconomical or threatens environmentally sensitive surface features. At the same time, advances in materials and technology have enabled highwall mining of coal that create blind headings over 300 meters in length. Deeper surface mining and deeper highwall penetration depths have lead to more frequent encounters with methane gas. While this coal is remotely mined from the surface, underground ignitions of methane have propagated to the surface and injured miners. Methods described in this paper show how this hazard can be correctly monitored and controlled for auger type highwall mining machines. Research indicates that small quantities of gas liberated during mining migrate to the face, creating higher gas concentrations than would otherwise be expected. Using the same principles that cause the gas to migrate to the face, researchers have shown that inert gas introduced at the collar of the hole can inert the entire hole, thus ensuring safe conditions for mining.

By B. J. Moore

This publication contains analyses and related source data for 191 natural gas samples from 22 states and 1 foreign country. Of the total samples, 182 were collected during calendar year 1987. The remainder were collected earlier, but releases granting permission to publish were not received before 1987. All samples were obtained and analyzed as part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by mass spectrometer and chromatograph.

Jan 1, 1988