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By Yong .. Jun Wu

Laminated ceramics have received widely scientific and commercial attention because their properties, such as mechanical properties and electrical properties, can be tailored by adjusting the structure, thickness and composition of the different layers. For example, ferroelectric Bi4Ti3O12 (BIT) which has a positive temperature coefficient of dielectric constant (,E) can be used to modify the negative tE of typical microwave dielectric ceramic BaNd2Ti4O12(BNT), However, BaNd2Ti4O12/Bi4TiO12/Bi4Ti3O12/BaNd2Ti4O12 (BNT/BIT/BNT) laminated ceramics could not be prepared by the general method because the optimal sintering temperature of BaNd2Ti4O12 ceramic (around 1350°C) was much higher than that of Bi4Ti3O12 ceramic (around 1100°C). In this research, a new method of spark plasma sintering (SPS) combined with post-sintering was successfully proposed to prepare BNT/BIT/BNT laminated ceramics. It was divided into three steps. In first step, the BaNd2Ti4O12 ceramics were prepared by conventional sintering method. In second step, the calcined and pre-pressed Bi4Ti3O12 powders were sandwiched between BaNd2Ti4O12 ceramic pellets and spark plasma sintered at 900°C for 10min to synthesize BNT/BIT/BNT composite ceramics. In the last step, a post-sintering was employed to reoxidize the partially reduced BNT/BIT/BNT composite ceramics. The results of scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) showed that BNT layer and BIT layer were well bonded and no significant interfacial infiltration between them was observed. The sandwiched BNT/BIT/BNT ceramic with 10.7% BIT in volume has a dielectric constant of 92.85, a low dielectric loss of 01068 and a small temperature coefficient of dielectric constant of 35 ppm/°C at MHz.

Jan 1, 2003

By Clara Godoy, Paulo Couceiro, Juan Navarro

The continuous automatization and digitalization of the different stages involved in any underground construction bring new possibilities to optimize the operation. One of the most important requirements for the development of these projects consist of a proper rock mass characterization for optimizing the stages of the drilling, blasting and support cycle. In the last few years the road to digitalization has gone through data science and big data, showing the importance of data gathered to describe the geological and geotechnical environment that surrounds the operations. Since rock characteristics have an important influence in the drilling response, the technological advances in the sensorization of drilling machinery such as the Measurement While Drilling system (MWD) allow to gather the necessary amount of information to be applied in data science processes to evaluate changes in the rock mass with higher resolution than conventional methods. In this paper, Machine Learning techniques have been used to combine data monitored from the drill rigwith scanner profiles of the excavated sections to develop an automatic geotechnical rock mass characterization model able to estimate potential zones of over- or under-break of the remaining rock mass in underground blasting. By comparison of scanner profiles of the excavated sections with the blasthole positions, an Excavated Mean Distance (EMD) between the contour blastholes and the excavated profile has been obtained, which may be considered as damage measure. Considering blasting factors as constant, the model combines the rotary, percussive, hydraulic flushing and the rate of advance of the drilling, and the confinement of the rock mass by depth, to detect zones with different rock properties. This provide an early information of the rock mass condition around the blastholes and the prediction of expected overbreak generated after blasting, being possible to design more efficient bastings, in which each borehole is filled with the right and necessary explosive charge. The analysis comprises data from 57 blasts (around 1700 contour blastholes) and more than 4000 excavated sections.

By Neil H. Bostick

This research, sponsored at Stanford Research Institute by the Grand Junction Operations Office of the U.S, Atomic Energy Commission, was an outgrowth of the concern that presently-known ore reserves may be inadequate to meet the projected demands of nuclear power reactors. The original program at SRI was to design a comprehensive geological information system and use it to store and analyze the very great quantity of data needed to estimate uranium ore reserves. Study of the problem showed that it could be solved only by use of modern electronic data processing techniques, so such a comprehensive system was designed and tested. The system test was satisfactory, but input lead time and total expense were shown to be too great for the system to be practicable for the AEC under present circumstances. Thus, based on results of the earlier research, a specialized and simplified procedure for predicting approximate uranium ore reserves was devised. The prediction is based on general geology of specific area cells of the earth, in order to provide complete volume coverage; the strata in these ores are evaluated for uranium ore favorability on the basis of a few selected criteria in order to allow rapid data input. Since the bulk of U.S. reserves are in clastic host rocks only such strata are considered in this work. This paper describes the structure and some details of the resource system and how it was tested in rn area of the western United States.

Jan 1, 1969

PROF RICHARD ÅKERMAN Stockholm, Sweden ANDREW CARNEGIR New York, N.Y. DR. JAMES DOUGLAS New York, N.Y. PROF HATON DE LA GOUPILLIERE Paris, France R.A. HADFIELD Sheffield England PROF HANS HOEFER Leoben, Austria PROF HENRI LOUIS LE CHATELIER Paris France M FLORIS OSMOND Paris, France JOHN E. STEAD Middlesborugh, England PROF DIMITRY CONSTANTIN TSCHERNOFF St Petersburg, Russia CHARLES D WALCOT Washingtion D.C. PROF DR HERMANN WEDDING Berlin, Germany

Jan 1, 1910

By Webster Smith

El cobre se encontró en Cornwall al mismo tiempo que el estaño debido a que ambos elementos se encuentran asociados en las minas. En ese sentido, el presente texto señala las primeras minas de cobre en Inglaterra, como las primeras prácticas de fundición de este metal, las fuentes medievales de cobre inglés, las fuentes de mineral más antiguo del extranjero, la expansión del cobre en la antigua China y en la antigua Grecia y Roma.

Jan 1, 1969

By Theodore A. Blake

At the Chicago meeting of the Institute, May, 1884,I had the pleasure of announcing the introduction of a new machine for fine crushing, or The Blake multiple-jaw crusher, which, in combina tion with the ordinary Blake breaker, could be used in the reduc tion of ores or any hard and brittle substance to almost any degree of fineness. I am now able to give some practical results derived from its use on an extensive scale, on the gold ores of South Caro lina and the iron ores of Lake Champlain, together with some accurate and detailed statistics of the cost of crushing over one hundred thousand long tons of magnetic iron ores of the Chateaugay Ore and Iron Company at Lyon Mountain, Clinton County, N. Y., about thirty miles west of Plattsburgh. The construction of the multiple jaw-crusher, since the date of my first paper, is the same, except in the substitution of main swinging, instead of main sliding, or toggle jaw,—thus doing away with the upward thrust on the tension rods and the wear incident thereunto. (See Fig. 1.) It has also been found, in case of the fine crusher, that is, in machines of not over 4 inch width of opening, that the use of several small machines with a series of jaw openings, say 15 inches by 4 inch, is better than one large machine with a series of openings 24 by 4 inch, or 36 inches by 4 inch, as at first constructed. Many details of the method of holding in jaw-plates, etc., have been perfected. Without giving any details with respect to the different mills built upon the Blake 'system, let me state that, although it has proved possible to carry any hard and brittle material with crushers alone to a fineness such that all particles will pass a 30-mesh wire screen, still the economical limit of such crushing will be found somewhere between 14 and 20. If it is necessary to carry all the material to a fineness greater than this, the system must be supple

Jan 1, 1888

By A. J. Rigby

Refractory linings in converters or anode furnaces used to over-oxidize the blister copper will suffer rapid deterioration, due to prolonged contact with copper oxide-rich slag. Nitrogen stirring with COP KIN porous plugs and use of SEMTECH OPC in converters and anode refining vessels can considerably reduce both refractory wear and processing times. In addition, careful control of the vessel atmosphere and the use of real-time optical process control minimize both slag volume and contact time with the vessel refractory.

Jan 1, 2005

By Felipe De Lucio Pezet

El presente trabajo describe el proyecto de renovación en la metalurgia extractiva del cobre donde se buscó mejorar la ley de sus concentrados, específicamente de Cobriza. Asimismo, este permitiría obtener utilidades similares a las que globalmente obtiene el complejo minero-metalúrgico de Cuajon-Toquepala de Ilo. Finalmente, el proyecto permite obtener azufre elemental para satisfacer la demanda interna y exportación.

Jul 1, 1987

By Frederic H. Lahee

After abandoning two dry holes, on the Mrs. Daisy Bradford land, C. M. Joiner finally completed his No. 3 on Sept. 8, 1930, at a total depth of 3592 ft. This well is 735 miles somewhat north of west of the town of Henderson, in Rusk County. Between Oct. 2 and Oct. 6, this well made numerous heads which indicated that it would produce about 300 bbl. daily. By Nov. 27, two dry holes,' completed near the Joiner well, taken in conjunction with the small production from this well, served to dampen any enthusiasm among those who hoped for a major pool; but by December 18 three other producers had been completed. On Dec. 28, 1930, E. W. Bateman's Lois Della Crim No. 1 drilled itself in with an estimated daily yield of between 10,000 and 15,000 bbl. from a depth of 3650 ft. This well, 10 miles north of the Joiner well, also in Rusk County, initiated the leasing campaign that led to the later orgy of drilling. On Jan. 25, 1931, Moncrief, Farrell and others completed their J. K. Lathrop 1 as another big producer, 7 miles east of Gladewater in Gregg County and 14 miles N. 20" E. from the Bateman Crim well. The Lathrop well, 3574 ft. deep, flowed 320 bbl. in 1 hr. through a ½in. choke. The first well completed in Smith County was Cook No. 1, drilled by Guy Lewis et al. in the James Jordan Survey, 4.7 miles west of the Joiner discovery well. On Mar. 30, 1931, it flowed 137 bbl. in 33 min, through a ¾-in. choke. The top of the pay sand was found at 3672 ft. Finally, in Upshur County, on May 5, the Mudge Oil Co. et al. completed the Richardson No. 1, which flowed 274 bbl. through a 4 2/64-in. choke in 2 hr. This well is 4 miles northwest of the Lathrop producer. Development It is unnecessary to give a lengthy description of the rapid development of the area discovered in these five far-separated wells, or to discuss the speculations offered as to whether there were several pools or only one.

Jan 1, 1932

By C. Green, J. Uhrie, C. Filippone, A. Guzman

A central aspect of heap leach management and recovery optimization is solution control. Insofar as each heap is unique in physical and metallurgical properties, it is essential to understand the hydraulic parameters that control the migration of solution on a case-by-case basis. Water Management Consultants, as part of an ongoing research effort for Phelps Dodge Process Technology Center, have adapted techniques of parameter estimation for application to data typically resulting from metallurgical column testing. The parameterization is completed within the context of a variably saturated flow model that allows interpretation of available hydraulic information collected during hydrometallurgical column tests. A novel interpretation approach is introduced to extract the necessary hydrodynamic parameters from typical hydrometallurgical data sets. Results from the application of the approach to standard metallurgical test data will be presented together with a discussion of the application of information gained to the design and operation of a heap.

Jan 1, 2002

By Carlos Herrera, Paulo Alcazar, Alex Conco, Fremy Flores

Las redes neuronales artificiales son un subconjunto del machine learning y están en el corazón de los algoritmos de Deep learning reflejando el comportamiento del cerebro humano, permitiendo así que las soluciones tecnológicas reconozcan patrones y resuelvan problemas comunes en los campos de la IA. Este modelo matemático es capaz de aprender a través de un aprendizaje supervisado de patrones de conocimiento. Se investigó una solución que involucra cuatro tipos de sistemas.

Sep 30, 2022

By Reed M. Izatt

SuperLig® materials are capable of individually separating Rh, Pd, and/or Pt in highly purified form (99.95 to 99.99%) from a variety of chloride-based feed streams in a single stage operation. The hydrophillicity and associated kinetics of the supported materials allow for operation at relatively high flow rates of both loading and elution in a packed bed format. Pilot and commercial systems have been operated with Rh, Pd, and/or Pt present in the feed from single digit ppm (mg/l) to tens of g/l. A dual SuperLig® system for one pass Au(CN)2- separation followed by Cu and CN- recovery for CN- recycle has also been tested up to a pilot level,

Jan 1, 1999

By X. Gumede

Mud houses are common structures in most South African rural homes closer to the mining operations. Fulltime dwellers in these properties are often the elderly. The mine codes of practice and the South African legislative instruments attempt to define the damage criteria to limit the effect of the blast-induced noise and ground vibrations to different structures. All these assessment criteria are based on the peak particle velocity and noise generated during blasting. The South African safe limit criterion that was adopted was initially derived from the international standards, which were then used as a local guideline. This paper evaluates the currently adopted safe limit criteria used in South Africa for a mud house, currently rated at 6 mm per second and 120 decibels to134 decibels, for blast-induced seismicity and noise, respectively. Further, a study was performed on a residential house near a coal mine (5.26 km) based in Mpumalanga following numerous complaints by the owner, launched at the mine and to the Department of Minerals and Petroleum Resources. The aim of the study was to measure the magnitude of blast-induced triggers experienced at the aggrieved homestead and to establish if there is a likelihood that an irritation or damage may be caused by these triggers. The seismometer was installed at about 2 m from the mudhouse, from 1 July 2022 to 31 of July 2022. Five blast-induced triggers were recorded during the period showing an average of 0.09 mm/s and 121 decibels for blast-induced seismicity and noise, respectively. The results obtained indicated a maximum seismicity of 0.15 mm/s. This seismicity was below the perceptible vibrations obtained from daily home activities such as walking, jumping, and door slamming, which produce 0.8 mm/s, 7.1 mm/s, and 12.7 mm/s, respectively. Seismicity was therefore not likely to have caused any annoyance and or damage. For noise, the results indicated a maximum of 123 decibels and an average of 121 decibels from five events recorded. A literature review suggests that slight damage may occur when airblast frequencies match the natural frequencies of structures at 120 decibels. Based on these results, it can be concluded, therefore, that the noise, rather than seismicity, is more likely to be the cause of damage to the structure assessed. For improvement, a new approach is proposed based on relating the safe limits to the structural and human response.

Dec 15, 2025

By NA NA

A round up of recent industry matters. Davis Derby acquisition of Safecom UEP Ltd. Record Output by Longannet Mine.

Jan 7, 1997

By Gregory P. Cole, Peter G. Kovalchika, Rudy J. Matetic, Adam K. Smith

Previous studies conducted by the National Institute for Occupational Safety and Health (NIOSH) have shown that approximately 90% of coal miners and 49% of metal/nonmetal miners had a hearing impairment by age 501. Mine workers are exposed to additional noise levels underground due to the reflection of machine generated noise that would otherwise dissipate in an above ground setting. Determining the sound absorption coefficients is essential in modeling the sound field in an underground mining environment. Sound absorption is a measure of the amount of acoustic energy that strikes a surface and is absorbed, rather than reflected. The acoustic environment that mining machines operate in is a critical factor affecting the sound pressure level exposure for mining machine operators. Impedance tube testing is an inappropriate method for determining underground absorption coefficients due to the brittle composition of some of the materials such as coal and slate. Classic absorption coefficient estimation using T60 measurements will not work well in an underground environment because the theory assumes: a finite room, a diffuse field, and relatively uniform absorption. None of these assumptions are true in an open-ended mine entry. This paper will present a method using a ray-tracing technique to determine absorption coefficients for underground mines. Absorption coefficients are determined and presented for octave bands from 63 Hz to 8 kHz. The absorption coefficients will be essential for determining and predicting potential overexposure to machine operators in different mine environments.

By Eder Villarreal, Jorge Chira, César Vilca

Este presente trabajo tiene como objetivo mostrar que el Instituto Geológico Minero y Metalúrgico, ha tenido un papel muy importante en el descubrimiento de yacimientos minerales. Referirnos a estos descubrimientos es remontarnos a las décadas de los 60, 70 y 80; en ese entonces, el Servicio Geológico del Perú (ahora INGEMMET) realizó una serie de convenios internacionales con los gobiernos de Japón, Francia, Alemania e Inglaterra, para estudiar Áreas de No Admisión de Denuncios

May 1, 2008

By Clara Godoy, J. A. Sanchidrian

In this paper, Machine Learning techniques have been used to combine data monitored from the drill rig with scanner profiles of the excavated sections to develop an automatic geotechnical rock mass characterization model able to estimate potential zones of over- or under-break of the remaining rock mass in underground blasting. By comparison of scanner profiles of the excavated sections with the blasthole positions, an Excavated Mean Distance (EMD) between the contour blastholes and the excavated profile has been obtained, which may be considered as damage measure.

Feb 1, 2020

By H. Sis

The pressure filtration behavior of dispersed and flocculated alumina slurries at high percent loadings is discussed with an objective to determine the effect of surfactant type and concentration on slurry properties. A high purity alumina powder was used as a model solid. Dispersion of the alumina was controlled by surfactants that are considered to act by electric and steric stabilizers. The effect of both the ionic and nonionic surfactants was investigated. Surface charge measurements of the slurries were carried out by electrokinetic sonic amplitude (ESA) method to understand the mechanisms. The effect of surfactant type and concentration on the kinetics of pressure filtration and final cake properties are discussed.

Jan 1, 1998

The Kaltails Project is situated close to the city of Kalgoorlie-Boulder in Western Australia. Located on the south-eastern fringe of the Golden Mile, Kaltails has been in operation since June 1989. The tailings forming the reserve for Kaltails have been derived from 100 years of underground mining on the Golden Mile, but, some of the re.;erve has been retreated in the past. A map of the tailings reserves and treatment plant site is presented as Figure 1. The gold project is a joint venture between Poseidon 90 per cent and Gold Corporation (ten per cent) and is managed by Poseidon Gold Kaltails.

Jan 1, 1992

By John Sasadi

Several years ago I wrote a comprehensive paper 'entitled, "Future Trend of Bulk Carriers" dealing with the principle dimensions of vessels and how they can be predicted; then with loading and unloading of large carriers, especially considering various designs of "Self Unloaders". Since writing the paper, many large bulk carriers were basically built along the, predictions made. Maximum size today is in the 150,000 DWT class, with few exceptions, which are combination carriers (ore-oil) or OBO's (oil-bulk-ore) in the 200-250,000 DWT class in the same paper, many references were made cautioning engineers not to design ports which could be "obsolete tomorrow", however, these were not always followed. Nevertheless, during the past few years many modern ports were built signaling the beginning of a new area of "Super Ports". Super Ports can be built for various reasons, most important to provide transfer stations where bulk material is received from large carriers then transferred to smaller vessels or barges for distribution. Obviously, opposite movement of bulk commodities can justify the building of "Super Ports", however, these are not as difficult to build for many reasons. The Material Handling Industry has developed efficient means of unloading smaller vessels or barges with continuous-type unloaders and has mastered the art of storing, reclaiming, and moving large quantities of bulk material to high-capacity shiploaders. Nevertheless, the industry has failed to design and market efficient ship unloaders which in any way could match the presently attainable shiploading rates. For these reasons, it is considerably more difficult to build "Super Ports" for incoming rather than outgoing bulk materials with large bulk carriers. The purpose of this paper is to elaborate on problems affecting high-capacity, continuous ship unloaders, especially involving large bulk carriers. For better understanding, some references will be made to the smaller, continuous barge or ship unloaders, but only as the principles affect the larger units. Additional references will also be made to exploit the present "State-of-Art" of the grab

Jan 1, 1972