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By M. H. Kotze, V. Yahorava

A gold-selective ion exchange resin, containing tributylamine groups, was developed by Mintek for the recovery of gold from cyanide leach solutions. The Dow Chemical Company and, more recently, Purolite commercialized the production of this gold selective resin for use in the gold mining industry, and it is marketed as Dow XZ-91419.00 and Purolite A194 respectively. A novel application of this resin is the selective recovery and separation of AuCl4 - f rom p latinum group metals (PGMs) in chloride and nitrate solutions. The current paper describes potential benefits of this type of resin for selective recovery and upgrading of gold from low grade chloride or nitrate waste streams, and the possibility of gold separation from PGMs during their refining in chloride media.

Jan 1, 2014

By J. Clark

Erosion control during the mining cycle can be more effectively planned using Erosion and Sedimentation Control Plans (ESCPs). This raises the issue of who should develop an Erosion and Sedimentation Control Plan Guidance document (ESCPG) to standardize the content of ESCPs. A search for ESCPG documents in Canada revealed no examples for mine sites. In the U.S. there are a number of regulatory authorities who developed such documents for mine sites, including EPA. An ESCPG is expected to result in: (a) plans will be more standardized (b) more clarity and efficiency for those generating ESCPs; (c) assisting regulators tasked with reviewing/approving ESCPs; (d) providing guidance for the mine effluent permitting process relative to sediment control; (e) providing a basis for developing and including ESCPs in the Environmental Assessment (EA) phase and the mine economic assessment; (f) applying and optimizing ESCPs above the ?watersheds? of sediment ponds; (g) utilizing the ESCPG document for ?exploration? sites; (h) lowering the risk of adversely impacting water quality downstream of mining activities; (i) providing a methodology for determining the need for sedimentation pond(s) during the construction and production phases; and (j) providing a clear environmental sustainability message relative to sediment control if the mining industry takes the lead in developing an ESCPG. ESCPs will proactively create increased administrative (regulatory) efficiency in the EA and sub-EA reviews relative to erosion control and sediment release from mine sites. This also assists the new initiative in BC, One Project, One Process (OPOP) and synchronous permitting (a variation of concurrent permitting): as an example, enhanced erosion control planning at the EA phase then allows the synchronous permitting initiative to proceed efficiently, particularly for the mine permit (Ministry of Energy, Mines and Natural Gas) and effluent permit (Ministry of Environment). Approximately twenty more management plans (e.g. ARD/ML, explosive management, emergency response, hazardous waste, sediment pond operation, environmental effects, environmental sampling, etc.) may also be entered into the EA process to create increased efficiency, and then feed into the synchronous permitting effort. The BC OPOP initiative also adds support to the Canadian Federal ?One Project, One Review Process? approach. The ESCP and a sediment pond management plan will also address the Canadian Metal Mining Effluent Regulations requirement for all discharges from mine sites to meet a grab sample of 30 mg/L Total Suspended Solids.

Aug 1, 2013

The purpose of this study was to investigate the effectiveness of froth fl otation for the recovery of gold from the gravity tailing stream of the former Lihir Gold Limited (LGL) operation in Ballarat. The P80 of the tailings was determined by screen analysis as 1 mm, with test work conducted on as received material along with samples ground to P80 sizes of 47, 78 and 134 microns. Laboratory scale batch flotation tests were conducted at both natural and elevated pH to investigate the impact of pyrite depression on gold recovery. Results indicated that although an increase in grade from approximately 0.7 g/t to 3 g/t was achievable at a natural pH and a P80 of 134 micron, gold recovery was low at just 35 per cent. Finer grind sizes were found to have an adverse effect on both grade and recovery. Future efforts will be focused on the sub 310 micron size fraction of the tailings, which was revealed to contain approximately 85 per cent of the available gold and may be amenable to cyanidation or ultra-fine gravity treatment.

Aug 1, 2010

In 1820, the Board of Public Works was considering some improvements to the canal, in order to reduce the cost of transportation, and in its annual report for that year gives a description of the method of loading the coal from the pit to the boat, and also from the boat to the dealer's yard, which is illuminating in showing how coal of this type should not be handled. It follows:- "It will be seen by the estimates, that the improving the present canal, forming a canal of large dimensions, from the head of the present lower canal to Sabbot Island; erecting locks of large capacity, and making a communication with the river, so as to completely accommodate the coal trade, (except it should hereafter be found necessary to make another communication with the river,) will not cost more than 126,000 dollars. But as there is some doubt whether the streams that may be received into the canal between Sabbot Island and the upper arch, will at all times be competent to supply the locks on that portion, we will extend our calculation to a point nearly half a mile above Pleasants' Island; where, by erecting a dam, any desired quantity may be thrown into the canal. This extension of the canal with one lock, and the dam across the river, is estimated at 34,000 dollars, making in the whole a little over 160,000 dollars. There will then remain a surplus of 40,000 dollars after completing the works to the point last mentioned. "In order to discover what effect the improvement of this first section will have on the tolls, it will be necessary to take a view of the present state of the coal trade, and endeavor to ascertain what change will result from the increased facility of transportation. "That part of the business which is carried on by water, is conducted nearly in this way. When the coal is drawn out of the mines, it is thrown in a heap near the mouth of the mine, or shaft; it is then loaded into carts, and carried to the river bank, where, in some instances, it is discharged from the cart at the brow of the bank, and runs down to the beach near the water's edge; then shovelled into wheel-barrows, and wheeled aboard of the boat, and discharged from the barrows by upsetting. In other instances, the carts are driven on to a kind of scaffold, furnished with a wide spout or director at the edge; by which the coal is conveyed immediately into the boats. These boats are the common James river poplar batteaux, and require three men to each. The up-stream navigation being laborious, the boats are built of light materials, and continue fit for service but a short time, (say) from two to three years; their cost, when new, from fifty to one hundred dollars. "When the river is tolerably flush of water, one of these boats will carry about two hundred bushels; but in low water their load is sometimes diminished to one hundred, and even as low as eighty bushels. They pay for passing the canals and locks to the Basin, one dollar per load; so that when full loads are taken, it will amount to half a

Jan 1, 1942

By Juan Silbino Marceliano Rojas

Volcan Compañía Minera S.A.A. es una empresa minera peruana que inicia sus operaciones en el año 1943. A lo largo de sus 71 años ha logrado posicionarse como la primera productora de plata, plomo y la segunda en zinc a nivel nacional. Durante este periodo la compañía se ha expandido y ha alcanzado excelentes resultados de productividad. Sin embargo, estos resultados no han sido acompañados de indicadores de seguridad favorables. En los últimos 12 años (2000-2011) se han presentado 88 fatalidades, 960 accidentes incapacitantes y 1400 accidentes leves. En el 2012, la dirección de la organización decide realizar un cambio trascendental en la gestión de seguridad, estableciendo como primer objetivo estratégico de la compañía la implementación de una cultura de seguridad de clase mundial para minimizar la frecuencia y la severidad de los accidentes de trabajo. Partiendo de este objetivo en el año 2012 realizó un diagnóstico a nivel corporativo que nos ubicó en una fase de dependencia en relación a la curva de cambio de cultura, tomando como base el concepto de Bradley e identificó la necesidad de efectuar un cambio en dos frentes: Sistema de Gestión SSO y Líderes. Diseñamos una "Estructura Organizacional" en los tres niveles de operaciones, lo que involucró a los líderes y evidenció así el "Liderazgo Visible". El sistema se basó en cuatro pilares fundamentales y aplicó las siguientes herramientas: gestión de riesgos, condiciones, conocimiento y comportamiento. Dentro del pilar condiciones, priorizamos doce riesgos críticos para contener los accidentes mortales e incapacitantes. Los Líderes fueron entrenados en la herramienta de gestión y en los cuatro pilares del sistema. De esta manera se logró el impacto directo en la supervisión y los trabajadores, así como desarrollar las competencias de comunicación, motivación, retroalimentación, confianza y compromiso. El modelo está evolucionando la cultura de seguridad hacia una fase de interdependencia. Hemos reducido los índices de frecuencia en un 55%, severidad en un 92% y accidentabilidad en 96%, sin embargo nuestro logro más importante es la contención de los accidentes mortales a la fecha.

Sep 21, 2015

By Louis Huber

DESPITE the fact that centrifugal fans were first developed for ventilating mines and that artificial ventilation was first practiced in mines, the lack of knowledge of mining men on mine ventilation in general, and on fan performances and characteristics in particular, is very much in evidence today. While it is true that mines are much better ventilated now than they were 20 to 30 years ago, we have made very little progress in the study of mine ventilation, or in mine ventilating fan design. Today the average mine operator is woefully dependent on the engineers of mine fan manufacturers when he is in the market for a fan, and this situation works to the disadvantage of both the operator and the manufacturer. The former may be imposed upon by an unscrupulous sales engineer and induced to buy a fan which is not the proper one for the mine; when it is operating it may be wasteful of power and even accessory to a serious mine disaster. More often, however, it is the fan manufacturer who is imposed on. If the operator asks the manufacturer to build for him a fan that will deliver a certain quantity of air against a certain specified pressure and requiring a specified number of horse power when operating under these conditions, the manufacturer may build a fan that will comply with these specifications to the letter. When the fan is installed it is frequently found that it is delivering a greater quantity of air against a lesser pressure or a lesser quantity of air against a greater pressure, and is requiring more horse power than specified in the first case and less than that specified in the second. In either case the operator usually upbraids the manufacturer for not meeting specifications, and refuses to pay for the fan. The trouble in either case outlined above is that the pressure necessary to force the specified quantity of air through the mine has been estimated incorrectly by the operator or his engineers. When a fan is designed and built to deliver a certain quantity of air against a certain specified resistance it will operate at its maximum efficiency only when it is operating under

Jan 2, 1926

By C. Gregory Knight

Adequate planning for the development, operation, and reclamation of a surface mine requires attention to present and future uses of land, both on the mine site and in the mine vicinity. This paper outlines land use implications of surface mining, and suggests procedures that could link mine planning, mine operation, and reclamation to more general land use concerns. Mining is viewed as a temporary use of land that may irretrievably commit land resources away from some future activities, but may allow other uses, some of which may have been impossible without mining. The paper accepts the premise that surface mining should attempt to minimize environ-mental damage and to maximize future alternative uses of land by appropriate reclamation. I. The Effect of Surface 1'1ining on Land Use Surface mining is a temporary utilization of the land most often criticized because the disturbances it creates are of far greater duration than the actual extractive operation, Resource recovery disrupts existing activity on the land, at least temporarily, and

Jan 1, 1977

By Oscar Silva C.

El presente trabajo señala la importancia del proceso de entrenamiento como parte de las funciones de supervisión. Por tal motivo, se describen cuáles son las cinco necesidades básicas del supervisor, el concepto de entrenamiento de la industria, cuándo se debe entrenar, el planeamiento del entrenamiento, las relaciones humanas y el entrenamiento. Una vez descrito el funcionamiento del supervisor, se obtendrán ventajas como el convertirse en un ejemplo para su personal, se disminuye la tensión del trabajo y se permitirá todo el tiempo necesario para el estudio y aplicación de técnicas, habilidades, capacitándose de esa manera para ser promovido.

Aug 20, 1963

By Spencer Ness, Yazen Khasawneh

Onshore wind turbines are complex and dynamic systems, undergoing variable environmental and mechanical loads. These dynamic loads are transferred through the turbine components and tower to the foundation system and, subsequently, the adjacent soil. As the size of onshore wind turbines continues to grow, intermediate-type foundations are being developed and implemented to better leverage the strength of the adjacent soils while avoiding some of the drawbacks of deep foundations. However, these foundations can be relatively sensitive to ground conditions. When considering a wind energy site that may consist of dozens of wind turbines across thousands of acres, it can be difficult to determine a design stratigraphy that is reflective of the entire site and takes conservative approaches to all potential failure modes and design checks. As intermediate foundations are inherently a soil-structure interaction problem, computer-aided numerical methods are often necessary. To highlight this condition a typical intermediate foundation with tower and turbine is assessed under eighteen different soil profiles within a finite element software and performance is compared.

Oct 7, 2024

By Alexandre Silva Guimarães

O presente trabalho avaliou o comportamento de extração dos metais cálcio, magnésio e níquel, contidos em licores sintéticos sulfúricos, utilizando-se o extratante Cyanex 272 (0,64 mol/L) e misturas entre Cyanex 272 (0,64 mol/L) e ácido versático (0,53 mol/L). Os resultados revelaram que a adição de ácido versático ao Cyanex 272 provocou um aumento nas extrações de cálcio, que atingiram cerca de 40% em pH = 5,1, decrescendo com a elevação do pH do licor até atingir aproximadamente em 15% pH = 5,9. As extrações de níquel (em torno de 80% em pH = 7,1) foram favorecidas, enquanto as extrações de magnésio permaneceram em torno de 75-80%, numa faixa de pH entre 6,0 e 7,0, em comparação com a utilização de apenas Cyanex 272 como extratante. O níquel pode ser separado dos metais cálcio e magnésio, pela mistura dos extratantes nas concentrações estudadas, em pH = 5,1, utilizando-se de 2 a 3 estágios de contactação.

Aug 7, 2018

By Quispe Mamani, Mayra Casas Azañero

The research is located within Asuncion and Cospan districts, which according to their geological features in contrast with previous studies pointing out Au, Mo and Pb anomalies create an environment of prospective interest. The objective is to use ASTER Satellite Images to identify ore-bearing hydrothermal alteration zones. To do this, processing techniques such as the combination of bands by RGB 943 and 461, band ratio 4/6, 4/5, 5/8 and 2/1 to identify advanced argillic, argillic to phyllic and propylitic alterations. In addition, indices defined by Ninomiya were used as a third technique in order to reinforce the data obtained from the previous techniques. The results in the study area are confirmed by the SAM spectral mapping technique using spectral signatures from the USGS library. Identifying kaolinite, alunite and pyrophyllite, assemblages of the advanced argillic alteration. Concluding in 3 areas of interest with the band ratios, 5 areas with the Ninomiya indexes and 9 areas validated with SAM, which were contrasted in 13 areas of prospective interest with well-marked argillic alteration.

Feb 1, 2025

By Hiroshi Nakazawa

An acid mine drainage in abandoned Horobetsu mine in Hokkaido, Japan, contains arsenic and iron ions; total arsenic ca.10ppm, As(III) ca. 8.5ppm, total iron 379ppm, ferrous iron 266ppm, pH1.8. Arsenic occurs mostly as arsenite (As (III)) or arsenate (As (V)) in natural water. As(III) is more difficult to be remove than As(V), and it is necessary to oxidize As(III) to As(V) for effective removal. 5mL of the mine drainage or its filtrate through the membrane filter (pore size 0.45m) were added to arsenite solutions (pH1.8) with the concentration of 5ppm. After the incubation of 30 days, As(III) was oxidized completely with the addition of the mine drainage while the oxidation did not occur with the addition of filtrate, indicating the microbial oxidation of As(III). In this paper, we have investigated the microbial oxidation of As(III) in acid water below pH2.0.

Jan 1, 2006

By J. C. Squire, E. W. Baker, G. A. Sullivan, G. W. Flathers

A mine collapse severs communication with trapped miners. Landlines are crushed and commercially available radios cannot penetrate hundreds of feet of dense, conductive earth without the use of regenerative repeaters that may also be crushed. This paper describes a proof-of-concept device that uses seismic P-waves, instead of radio waves, to allow communication of a code that represents prearranged messages, including the safe haven location identifier, number of people and air quality, from trapped miners to aboveground rescue units. The transmitter designed is about 0.03 m3 (1 ft3) in size and can broadcast for four hours from its 27-kg (60-lb) battery pack. The receiver consists of a geophone and a 2.5-kg (5.5- lb) signal conditioning unit attached to a laptop computer, which displays the communication signal in real time. Testing in a bituminous coal mine with an MSHA representative revealed the device was able to transmit through 271 m (890 ft) of overburden, at 0° and 12° from vertical, using 500 W of power.

Jan 1, 2009

By Cyril Smith

THE following table, which is composed of data given in the author's first paper on the thermal conductivity of copper alloys1, contains the results which have been obtained by previous workers on the thermal conductivity of the copper-tin, the copper-phosphorus and the copper-tin-phosphorus alloys (the phosphor bronzes). TABLE 1.-Previous Investigations Composition, Per Cent. by Weight Thermal Conduc¬ Investigator tivity, Cal/Sq. Cm./ Copper Tin Phosphorus CM./Sec.. °C. Hardebecka 95.0 5.0 0.176 (20° C.) Grossmanb 90.1 9.9 0.105 75.5. 24.5 0.059 24.9 75.1 0'.139 (13° C.) 9.7 90.3 0.131 0.0 100.0 0.142 Griffiths and Schofieldc 91.7' 8.0 0.30 0.108 87.2 12.4 0.40 0.087 (20° C.) 90.0 10.0 Small amt. 0.100 Donaldsondd: 87.8 1 11.3 0.35 0.128 Pfleiderere 99.4 1 0.63 0.250 (30° C.) 98.0 1.98. 0.125

Jan 1, 1930

By A. Kenneth Schellinger, O. Cutler Shepard

INTRODUCTION OVERGRINDING, or the breaking of ore particles into sizes smaller than required for liberation, is a first-magnitude problem in grinding for concentration processes. The conventional ball mill-classifier circuit used in commercial grinding produces mineral particles that are all ground to pass an upper size limit, while the proportion of very fine sizes, or slimes, is uncontrolled. Calculations based on measurements made in commercial plants which were grinding ore for flotation concentration indicate that about 90 pct of the energy used in grinding is consumed in useless overgrinding.1 In addition to accounting for the consumption of a large amount of energy, overgrinding is detrimental to the flotation process. Overground slime coats larger particles and inhibits selective action by the flotation reagents on particles which by themselves could be separated very well. A further difficulty is that extremely finely ground minerals do not respond satisfactorily to flotation-collecting reagents, and both selection and recovery decrease markedly with particles finer than 5 to 10 microns.2 Conventional classifier-ball mill circuits inherently tend to overgrind the valuable minerals more than the gangue minerals because most valuable minerals are of higher density and are softer and more friable than the gangue minerals. The remedy to this situation would seem to be a separating mechanism which would separate free valuable mineral particles regardless of size and density considerations and a mechanism which would operate in the grinding mill so that valuable mineral grains would be removed from the grinding machine as soon as they are freed. A consideration of these ideas led the authors to the conception of a simultaneous grinding and flotation mechanism. So far as the authors are aware, such a machine has never been tried, even on a laboratory scale. DEVELOPMENT OF APPARATUS AND EXPERIMENTAL METHOD Apparatus development went through several stages before a really workable machine was devised. Work was started with a large cast-iron mortar 7 ½ in. in diameter and 8 in. deep. A cast-iron disk was mounted on the end of a vertical shaft so that it fitted loosely into the bottom of the mortar. On top of the disk four radial cleats ¼ in. high were bolted to agitate the ball charge as the disk, or impeller, rotated. The vertical shaft was driven at 100 rpm by a mechanism improvised from an old coffeemill type of grinder. A hole was drilled into the bottom of the mortar through which compressed air was introduced for frothing. In operation, weighed charges of ore which had been crushed to pass an 8-mesh screen were placed in the bowl along with water and suitable reagents. The impeller was then started and the compressed air turned on so that the ore was ground while being exposed to air bubbles. Mineralized froth was

Jan 1, 1947

Gold Fields Ghana Ltd (GF Ghana) currently operates an underground mine at Tarkwa, in south--west Ghana. The mine was operated by Tarkwa Goldfields Limited, a wholly owned subsidiary of the State Gold Mining Corporation of Ghana (SGMC). The mine was making operating losses and in a poor state of repair. Tarkwa Goldfields retrenched all the staff and GF Ghana assumed management responsibility for its own account on I July 1993.

Jan 1, 1997

By N. A. Zeigler

Considerable work has been and is being done on the changes of physical properties that take place in alloys at elevated temperatures, and much information on this subject is published. Much less is known, as pointed out by Rickett and Woodll about reactions between the alloys and atmospheric gases and still less is known abut changes within the alloy itself under the influence of heat and given atmosphere. Moreover, most of the work published has been done on the alloys of "heat-resisting" type, in which chromium is an essential ingredient, the behavior of all other alloys being quite unknown, except perhaps of decarburization produced at the surface by oxidizing atmospheres. It has been shown2 that iron, with total amount of foreign ingredients not exceeding 0.01 per cent, if heated in an oxidizing atmosphere at above 900" C., may be saturated with oxygen to 0.1 per cent. It was suspected that something of a similar nature may take place in iron-silicon alloys (transformer material), the mechanism of such processes being either a direct diffusion of oxygen into the alloy, or oxygen combining with silicon to form SiO2 or more complicated (silicate) inclusions. Another possibility to be considered was that during annealing in oxidizing atmospheres, when scale is being formed, silicon may oxidize preferentially at the surface, thus impoverishing the alloy in silicon. In collaboration with Dr. T. D. YensenP3 the writer set out to investigate this problem about two years ago in order to settle these questions. Testing Procedure In the first part of the investigation, two pieces of 4 per cent silicon iron, prepared in hydrogen atmospheres and forged to 3/4-in. square bar,

Jan 1, 1934

By X. F. Cao

There was a large reserve of bauxite resources in China. And these resources were mainly the dias-pore-bauxite and contained plenty of aluminosilicate including kaolinite, illite and pyrophyllite. Reducing the contents of aluminosilicate would be significant to the using of Chinese bauxite resources. In this paper, from the single mineral flotation experiments, the surface properties and flotation beha-viours of aluminosilicate including kaolinite, illite and pyrophyllite, using dodecyl amine (DDA), N, N-dimethyl-dodecyl amine (DRN12) and N-dodecyl-1, 3-propane diamine (DN12) as collectors, had been investigated. The flotation results shown that the flotation behaviours of aluminosilicate had been influenced greatly by three amine collectors; and the effect was in the order of DN12>DRN12 >DDA. On the basis of FT-IR spectra and zeta potential measurements, the ionization of surface hydroxyl, as well as isomorphic exchange of surface ions, accounted for the mineral surface charges. And the mechanisms of interactions between the mineral surface and collectors mainly included two modes: electrostatic adsorption and hydrogen bonding; for the DDA and DRN>DDA. 12, the mechanism was mainly electrostatic adsorption; and for the DN12, the mechanisms of electrostatic adsorption and hydrogen bonding both existed. Results of quantum chemistry research shown that the collecting ability of amine collectors was greatly influenced by the electro-negativity of N in the amine molecules; and The |E(EHOMO| and ?E (HOMO-ELUMO) of N atom in DRN12 and DN12 were lower than that of DDA, and the positive charge of ?N group in DRN12 and DA12 were higher than that of DDA. All these calculation results could explain the collecting power of DN12>DRN12>DDA.

Jan 1, 2014

By J. P. Vandenhoeck

Sizing devices used commercially are unfortunately not 100% efficient, the splits that can be obtained are usually inferior to the results obtained in the laboratory. Often the capital and operating costs of equipment capable of high sizing efficiency cannot be justified by the economics or requirements of the process. To reconcile the desired sizing efficiency needed to obtain optimum process requirements with the sizing efficiency of equipment economically practical, it is often necessary or desirable to predict the gradation and weight splits of the products obtained based on the expectant efficiency of the contemplated sizing device or method. The less efficient the sizing device one must employ, the more important it is to know the results that may be expected for the establishment of the optimum flow sheet and the more difficult it becomes to estimate the results accurately. Air classification equipment which sizes materials by opposing the drag force created by an air stream acting on a particle with a combination of gravitational, inertial or centrifugal forces are substantially less efficient than, for example, a laboratory sieve analysis. Air classifiers allow oversize material to contaminate the fine fraction and leave undersize material in the coarse fraction. The techniques employed to predict the gradation and weight splits obtained from air classification outlined below are adaptable to other sizing devices less than 100% efficient such as screens, sifters and wet classifiers.

Jan 1, 1965

By T Vijayakumar, Vipul Dobhada, Rajesh Patel, Swarnadip Dey, Naveen Babu D

The most challenging scope of any bridge project in marine or inter tidal zone is to construct sub structure like well Foundation, group pile, pile cap etc. Similarly, it also affects the marine environment/ecology to a great extent. Understanding the level of difficulties and aiding to provide an environment friendly solution, various options are analysed to overcome these and found mono pile to be the best alternative in this context. Generally, the foundation type of any bridge constructed in river, marine or intertidal zone in India is preferred for group piles. For the first time, monopile is being accepted as the foundation of bridge in India at Mumbai Coastal Road Project. The diameters of the monopiles used in this project are 2.5 m and 3.2 m. Hence, the challenges involved in monopile construction and experiences to overcome it are worth to share. Here, a brief discussion on environmental, geological issues and the needs of monopile as the foundation of bridge has been discussed. Furthermore, the monopile construction stages and confirmation of monopile capacity through different load tests have been elaborated.

Sep 1, 2022