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By R. S. Douglas

Introduction During the past few years, a number of changes in the mine operations at Copper Mountain have taken place. The modernization and mechanization were necessitated and given impetus by wartime and other conditions, which were: (1) The urgent need for copper for wartime purposes. (2) The scarcity of skilled labour for underground work. (3) The increase in labour and supplies cost. (4) The necessity of finding ways and means of increasing the output per man-shift, because of the scarcity of skilled labour and the rising cost of labour. (5) The desire to increase safety measures, reduce the silicosis hazard, and aid mine ventilation. (6) The desire to improve the general working conditions in the mine for all workmen. (7) The desire to reduce the amount of dilution in the ore stream by a more selective yet highly productive method of mining. To this end, mining with diamond drills, and transferring broken ore with slusher hoists, appeared to be the answer to the problem. After considerable discussion and estimation of costs for comparison with those of the operation as carried on at that time, the proposed methods were tried out and, in practice, gave very gratifying results. Reference at this point is made to the paper written by C. H. Brehaut, W. N. Taylor, H. A. Shannon, and R. S. Douglas, which was published in the September, 1945, issue of Mining Technology, by the American Institute of Mining and Metallurgical Engineers, Inc., and subsequently in commercial mining journals. Since that time some improvements have been made in undercutting an orebody - the first through experiment and practice, the second through making use of the earth's barodynamic or gravitational forces. It is the purpose of this paper to describe and discuss these later developments.

Jan 1, 1947

By W. H. Emens

[This circular is one of a series dealing with tie development and equip¬ment of small and medium size mines, and with the costs of such work prior to productive operation. The preparation and publication of these papers by the Bureau off Mines has been made possible through the cooperation of various min¬ing and development companies. The bureau of Mines has published a series of circulars dealing with min¬ing methods and costs at a large number of producing nines in the United States, Canada, Mexico, an, other countries. Unit costs of development work, shaft sinking, (rifting, crosscutting, tunneling, and raising are usually much higher in the preliminary development of a property than during its productive life.]

Jan 1, 1933

By A. Kontopoulos

The Olympias Mine in Northern Greece is producing an extremely refractory gold-bearing arsenical pyrite concentrate, containing on the average 41 3 S, 40 3 Fe, 10-12 3 As, 25 ppm Au and 35 ppm Ag. During the process selection stage, more than a dozen alternative technologies? were considered and an in-depth analysis was prepared for the three most promising, ie roasting, pressure oxidation and biological oxidation. Detailed capital and operating cost estimates were prepared, based, where appropriate, on laboratory and pilot-plant tests. A number of criteria was used for process evaluation and selection, including capital and operating costs; environmental impact, gold' recovery, stage of development, etc. Based on the above evaluation, the Sherritt Pressure Oxidation Process was finally selected. A detailed description of the process selection stage, supported with laboratory and pilot-plant test results on many of the processes considered, will be? presented.

Jan 1, 1989

By R. V. Lundquist

Aeration in water slurries and controlled drying of manganous hydroxide produced from dithionate leaching of Artillery Peak manganese ores from Arizona were investigated by the Bureau of Mines at its Electrometallurgical Experiment Station, Boulder City, Nev., to determine whether a simple process could be developed for converting this product into a battery-grade manganese dioxide. The properties of manganese dioxide prepared by the thermal decomposition of manganous nitrate were investigated also. Manganese dioxide suitable for use in batteries was not obtained from the dithionate leach product, but some of the factors controlling its oxidation were isolated. Aging of manganous hydroxide was of major importance in retarding its oxidation by aeration. Sodium hydroxide and sodium silicate promoted oxidation by drying. Optimum quantities were about 0.85 mol of sodium hydroxide and 0.2 mol of sodium silicate per mol of manganese, and drying temperatures of 200° C. produced yields of manganese dioxide up to 90 percent of the manganese present. Higher temperatures and concentrations of reagents carried oxidation of manganese beyond its tetravalent state.

Jan 1, 1957

By R. J. Kuczynski

The U.S. Bureau of Mines Reno Research Center investigated, developed, and patented a high-temperature cyanide leaching process for recovering platinum-group metals (PGM) from automobile catalysts. A batch pilot plant was constructed at the center and operated to demonstrate this technology to industry. Approximately 1,600 kg of used pellet, monolith, and metal support catalysts containing 1,700 g (54 tr oz) of PGM was processed. Forty-five-kilogram batches of used catalysts were leached with sodium cyanide solution at 160°C for 1 h in a countercurrent processing sequence. This selectively dissolved the PGM. Average extractions from the used pellet catalyst were 96 pet Pt, 95 pct Pd, and 73 pct Rh. Average extractions from the used monolith catalyst were 84 pct Pt, 81 pct Pd, and 66 pet Rh. Heating the pregnant leach solutions to 275°C for 4 h destroyed the PGM-cyanide complexes, causing over 99.7 pct of the PGM to precipitate from solution. The PGM precipitate was predominantly a metallic powder concentrate, typically analyzing greater than 50 pct PGM. Heating destroyed the cyanide to less than 0.2 mg/L free and total cyanide. Both the pellet and monolith residues were evaluated for disposal using the toxicity characteristic leaching procedure developed by the U.S. Environmental Protection Agency.

Jan 1, 2010

By S. R. McCutcheon, D. R. Lentz, W. S. Downey

"Abstract - The Little Falls member of the Nepisiguit Falls Formation is situated in the northern part of the Brunswick Belt of the Bathurst Mining Camp and has been interpreted as the distal equivalent of proximal tuffaceous rocks that host the stratiform Brunswick No. 12 and No. 6 Pb-Zn massive sulfide deposits. It comprises fine-grained, greenish-gray tuffaceous sandstone in the lower part, and coarse-grained, crystal-rich tuffaceous sandstone in the upper part. Petrographic evidence suggests that these rocks have a turbiditic origin. The Little Falls member is underlain by the Vallée Lourdes member, mainly composed of relatively shallow-water calcareous rocks, and is conformably overlain by Mn-rich sedimentary rocks, mainly red argillites that host the Tetagouche Falls Mn-(Fe) deposit. All these rocks are considered to belong to the Nepisiguit Falls Formation, part of the Ordovician Tetagouche Group. Whole-rock geochemical data from the fine-grained tuffaceous sandstone and coarse-grained tuffaceous sandstone indicate that the two units of the Little Falls member are distinct. Zr and TiO2 contents, and total rare earth element (REE) values are higher in the coarse-grained unit (average Zr/TiO2 = 0.040, average SREE = 247 ppm, n = 6) than in the fine-grained unit (average Zr/TiO2 = 0.048, average SREE = 158 ppm, n = 17), which can be attributed to the variation in crystal content between the two units. Both units are HREE-enriched and have elevated La/Yb relative to the typical Nepisiguit Falls Formation. Overall, the geochemical data combined with evidence from the bounding units suggest that the Little Falls member was deposited in relatively shallow water, possibly in a near-arc environment. The relationship of volcanic facies within the Nepisiguit Falls Formation and the geochemistry of these facies indicate strongly that fine grained, reworked tuffaceous rocks, regardless of whether they are the distal equivalents of proximal tuffaceous rocks, are not associated with the major ore-bearing horizons of the Bathurst Mining Camp. Sommaire - Le Membre de Little Falls de la Formation de Nepisiguit Falls se retrouve dans la partie nord de la Ceinture Brunswick du Camp Minier de Bathurst ou elle a été interprétée comme l’équivalent distal des roches tuffacées proximales hôtes des gisements de sulfures massifs de Pb-Zn stratiformes Brunswick No.12 et No.6. Il consiste en grès tuffacé à grains fins gris verdâtre dans sa partie inférieure et en grès tuffacé à grains grossiers riche en cristaux dans sa partie supérieure. Les données pétrographiques suggèrent que ces roches ont été déposées par des courants de turbidité. Le Membre de Little Falls repose sur le Membre de Vallée Lourdes, lequel consiste principalement en roches calcareuses déposées en eau relativement peu profonde; il est de plus recouvert en concordance par des roches sédimentaires manganifères, lesquelles consistent principalement en argilites rouges hôtes du gisement de Mn-(Fe) de Tetagouche Falls. Toutes ces roches appartiennent à la Formation de Nepisiguit Falls, laquelle fait partie du Groupe de Tetagouche, d’âge Ordovicien. Les données lithogéochimiques des grès tuffacés à grains fins et à grains grossiers indiquent que ces deux unités du Membre de Little Falls sont distinctes. Les teneurs en Zr et en TiO2, ainsi que la teneur totale en Éléments des Terres Rares (ÉTR) sont plus élevées dans l’unité à grains grossiers (Zr/TiO2 moyen = 0.040, SREE moyen = 247 ppm, n = 6) que dans l’unité à grains fins (Zr/TiO2 moyen = 0.048, SREE moyen = 158 ppm, n = 17), ce qui pourrait s’expliquer par la variation de la quantité de cristaux dans chacune de ces deux unités. Chacune de ces deux unités présente un enrichissement en ÉTRL ainsi qu’un rapport La/Yb relativement plus grand que ce qui est typiquement observé dans la Formation de Nepisiguit Falls. Les données géochimiques considérées conjointement à l’information provenant des unités adjacentes suggèrent que le Me"

Jan 1, 2006

By Personal técnico de la concentradora

El objetivo del trabajo es señalar los beneficios obtenidos en la planta Sacracancha a través de la instalación de un sistema económico de remolienda de baja inversión, readaptando sus molinos de bolas originales. Para ello, se requiere de una liberación adecuada de partículas para cada tipo de mineral y así obtener los resultados metalúrgicos satisfactorios en las plantas de flotación. La aplicación de este sistema en la concentradora de Sacracancha, la resolvió el problema de dureza de los minerales, encontrándose que la inversión fue pequeña, comparado con el costo de instalación de un molino de barras. Asimismo este circuito de molienda es elástico, dado que puede trabajar con molienda en una sola etapa, remolienda parcial, o remolienda total.

Aug 20, 1963

By A. Warczokand

The cleaning of copper smelting slag requires magnetite and cuprous oxide reduction. The slag reduction with coke, injected coal powder or bunker oil is strongly endothermic and requires heat generation by fuel combustion or the use of electric energy. The reduction of fayalitic slag with calcium carbide is slightly exothermic and the formed calcium silicate modifies the slag. Thus, the additional energy is required only for covering furnace heat losses. Results of crucible scale tests showed the rate of slag reduction approximately five times higher in comparison of the slag reduction with coke under the same conditions. It seems that the effect of exothermic reaction and slag modification with CaO at the reaction interface results in very high rate of slag reduction. Industrial scale tests carried out in the Anglo-American Chagres Smelter demonstrated the possibilities of effective reduction and cleaning of the slags from a flash smelter and Peirce-Smith converters in a Teniente Slag Cleaning Furnace. The slag reduction was carried out without any reductant or stirring gas injection, simply by calcium carbide charging through a furnace mouth, and was very fast.

Jan 1, 2007

By Xie Zhang, Chongyang Zhao, Qingyun Huang, Bing Xie, Xiaopeng Zhen

"Extracting vanadium from vanadium containing hot metal into vanadium slag by BOF is the main vanadium production process in China. In this paper, the influence of Si content in hot metal on the quality of vanadium slag is analyzed. Synthetic vanadium slag with different SiO2 content were melted at 1673 K and then cooled to 303K at the cooling rate of 3?/min. Optical microscopy, SEM, EDS and XRD were used to analyze the mineralogical phases and crystallization behavior of vanadium slag. The results show that vanadium slag mainly contains spinel phase and silicate phase; V is enriched in the spinel phases while Si is concentrated in Fe2SiO4 CaFeSi2O6 and (Fe,Mn)2SiO4 as silicate phase. The melting point of slag increases gradually with the addition of SiO2; whereas viscosity decreases with an addition of 15~19% SiO2 and increases with an addition of 19~27% SiO2.IntroductionVanadium is an important element which is used almost exclusively in ferrous and non-ferrous alloys. The major vanadium products include FeV, V2O5, V2O3, VN and Al-V-Ti alloy. Furthermore, vanadium slags are mostly produced by oxidizing the elements in V-containing hot metal during a duplex refining process. Therefore, the process of removing vanadium from hot metal has its significance on the subsequent process[1].The extraction of vanadium is greatly affected by the mineralogical composition of vanadium slag[2], the distribution of the elements between the spinel and silicate phases and its physic-chemical properties. These characteristics of vanadium slag have been studied in some details. It has been reported that Si mainly exists mainly in the form of silicate which wraps the spinel crystals while small amount of Si stands as phosphorus quartz or diopside[2]. Chen et al.[3, 4] points out, when SiO2 content in vanadium slag increased every 1%, V2O5 decreased 1.48%. Moreover, silicate phases would embarrass the oxidation of V-containing spinels through decreasing the exposing probability[5]. Meanwhile, melting point and viscosity of vanadium slag has been greatly influenced by the SiO2 content. Therefore, this work attempts to analyze the above-mentioned questions systematically."

Jan 1, 2012

By S. Kashani-Nejad

The formation of oxides during the dehydration of MgC12,6H20, Bischofite, was studied by heating the bischofite over a range of time and temperatures in ambient atmosphere. Using a methanol-leaching technique developed by authors, the oxides that formed were isolated, identified and assayed. Three distinct regions of oxide stability were identified. The oxide produced at dehydration temperatures less than 300 °C was Mg2(OH)3C1,2H2O; at 300 °C, mixtures of MgOHC1 and Mg2(OH)3C1.2H2O were formed and at 400 °C, MgOHC1 was the only oxide produced. The presence of MgO observed in the products of the dehydration of bischofite at temperatures above 400 °C was due to the thermal decomposition of the MgOHC1 that was formed while the sample was heating to over 400 °C.

Jan 1, 2006

By P. Roghanchi

The difficulties associated with performing direct tensile strength test lead to development of indirect test methods, which are simple, less expensive, and less time consuming. Splitting tensile strength test (Brazilian test) is performed by applying two opposite concentrated compression load across the diameter of a disk specimen until the failure occurs along the loaded diameter. Theoretically, the load is applied over a small width as a line load, however, by increasing the load, the contact width between the loading jaw and the specimen increases as the specimen deforms. The main aim of this study is to investigate the stress distribution in (1) regular Brazilian specimen in traditional tests with loading jaws and (2) flattened Brazilian specimen with flat platens. A series of the splitting tensile strength tests and uniaxial compression strength tests are performed on three rock types: rhyolite, basalt, and limestone. Further, Numerical modeling studies are performed to investigate the effect of the contact between jaw and Brazilian specimen on stress distribution in the disc specimen based on the results from the experimentation. Finally, the stress distribution in the traditional Brazilian test specimen and the flattened end Brazilian test specimen were compared.

Feb 23, 2014

By Julian Malnic

The emerging marine minerals exploration and mining industry is currently focused mainly on the technical elements for its success such as developing exploration and mining technologies. However, in one sense, the technical challenges are quite soluble whereas those arising in the fields of the environment and public opinion could present this new generation of miners with problems that are far more difficult to overcome. One need only look at the issues currently faced by mining projects on land to see how powerful the new forces of so-called ?civil society? are in stopping mineral developments in many countries. From the geographic viewpoint, there are many countries but there is just one ocean, so the impacts experienced by any one operation are likely to have pervasive repercussions throughout the industry. A well-oiled NGO development protest lobby will see leverage in resisting this new industry and will seize on the single-ocean angle. The Australian Minerals Industry has established a voluntary Code for Environmental Management that provides an active and valuable model for satisfying the ?court of public opinion? and in delivering economic results to industry that are in current jargon, sustainable. An explanation of the Code for Environmental Management, and the reasons behind 44 companies representing more than 300 operations and 85% of Australia?s sizeable mineral production being signatory to it will be given. Participants see it as a means to future shareholder wealth.

Jan 1, 2000

By L Semenyna, W Douglas

Gold is often present in solid solution with pyrite in the Carlin Trend. The presence of organic carbon along with gold hosted in sulfide, referred to as double refractory ore, requires that ore with high carbon-in-leach (CIL) preg-robbing potential and poor leach recovery is routed to a roaster. During roasting, the pyrite is oxidised to (ideally) form hematite (Fe2O3), and the gold that was present as solid solution in the pyrite forms colloids within the hematite. The ideal texture of the produced hematite is porous to allow for the penetration of cyanide for gold dissolution. Temperature and other conditions of roasting, as well as ore characteristics (pyrite mineral associations, arsenic) can affect the texture and the type of iron oxide formed. Many of these alternate iron oxide minerals result in incomplete leaching. Comprehensive gold deportment studies have proven that the majority of the gold losses in Barrick GoldstrikeÆs roaster leach tailings occur within the iron oxides created through the roasting process.The iron oxide phase that hosts the majority of the gold in tailings is in the form of by-product maghemite (?Fe2O3), which is highly magnetic. Barrick Goldstrike has designed a magnetic recovery circuit to capture these iron oxides, and with subsequent reprocessing, recover the lost gold. Pilot plant results and analysis using scanning electron microscope mineral liberation analyser (SEM MLA) shows that up to 30 per cent of the gold in tailings can be recovered with a three per cent overall mass pull to magnetic concentrate. This magnetic concentrate can be economically reprocessed, resulting in a three per cent improvement in roaster recovery.CITATION:Douglas, W and Semenyna, L, 2013. Magnetic recovery of gold-bearing iron oxides at Barrick GoldstrikeÆs roaster, in Proceedings World Gold 2013 , pp 79-86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Salustio s. Guzman

The standard .free energies of formation of tin chlorides were estimated with reviewed and estimated basic thermodynamic data, and measured reversible potentials for the disproportionation of tin dichloride into metallic tin and tin tetrachloride. Values for cºp, Sº, Hº?-Hº 298, -(Gº - Hº298) /T,.Hºf, Gºf, and log Kp are given in tabular form, these estimations are compared with estimations reported in the literature.

Jan 1, 1985

By Jorge A. Vargas

El proyecto Antapaccay es un depósito tipo pórfido-skarn de Cu (Ag, Au y Mo) perteneciente a la División Sur de Xstrata Copper, donde se tiene planificado la explotación a través de dos tajos abiertos denominados Norte y Sur. Para ello, se realizó una extensa campaña de investigaciones geotécnicas con la finalidad de determinar los parámetros geotécnicos y el comportamiento geomecánico del macizo rocoso presente y así evaluar la estabilidad de los taludes de diseño. En ese sentido, el presente textoseñala los análisis geoestadísticos (variografía) de los parámetros geotécnicos empleando el método de interpolación espacial kriging, presenta el modelo geotécnico a través de los parámetros geomecánicos de resistencia, así como la metodología seguida en los análisis de estabilidad con el método rígido plástico bidimensional de equilibrio límite.

Sep 14, 2009

By Winston W. Spencer

ALTHOUGH by far the largest A consumer of platinum metals in the world, the United States until recently has been in- significant as a producer. Writing in the "Minerals Yearbook" for 1939, H. W. Davis states that 1938 probably marked the beginning of an- other period of transition in the world production of the platinum metals. In that year, he says, their production in the United States jumped to 49,380 oz., or fourth in the rank of world output. In the ten-year period 1925 to 1934 United States output ,averaged only 8300 oz. Practically all of this sudden in- crease in production is attributable to the introduction of mechanized equipment at the placer deposits in the Goodnews Bay district of Alaska. This district adjoins the Bering Sea and Kuskokwim Bay (accented on the first syllable), and is approximately 120 miles south of the mouth of the Kuskokwim River. The nearest village and post office is Platinum, which lies about eleven miles north- east of the Goodnews Bay Mining Company's camp. A good gravel road connects the mine camp and the village.

Jan 1, 1940

By Rodrigo Vitorino da Silva

Ligas a base de zircônio utilizadas na indústria nuclear estão sujeitas à formação de hidretos que são causadores de efeito deletério no material. Para aumentar o tempo de operação desses componentes, é necessário o desenvolvimento de novas ligas que retardem ou diminuam esse efeito. Este trabalho tem como objetivo avaliar a influência da adição de elementos de liga em uma liga inédita a base de Zr-Nb na absorção de hidrogênio, através de testes que avaliam a absorção de hidrogênio e a formação de hidretos no material após processamento termomecânico e comparar seu desempenho com duas ligas comerciais. Para tal, foram realizados ensaios de microdureza, cinética de absorção de hidrogênio e micrografias. Os resultados de microdureza Vickers das três ligas estudadas, após o processamento termomecânico, são muito próximos. As curvas de cinética de absorção de hidrogênio mostram que a liga Zr-Nb-Sn-Fe apresenta melhor comportamento que as demais uma vez que o tempo para o início de absorção foi maior. As micrografias indicam que a liga proposta apresenta um desempenho superior em relação à morfologia dos hidretos visto que os mesmos são mais curtos e alinhados.

Aug 17, 2017

By Maria Sílvia Camarão de Sousa

Nesse estudo foi fabricada uma matriz hipoeutética de Al-2%Ni e adicionado nela a concentração 1,0 % de nanotubos de carbono de paredes múltiplas (NTCPM). A fabricação do material estudado aconteceu por fundição e resfriamento unidirecional brusco originando grãos predominantemente colunares. Os ensaios mecânicos mostram que concentrações maiores de nanotubo na matriz provocam acréscimo na propriedade mecânica e que em áreas mais distante da base extratora de calor a microdureza aumenta. As curvas de tensão-deformação, para os materiais estudados, evidenciaram que o acréscimo de 1% NTC na liga de Al-2%Ni teve como resultado, uma alta deformação plástica. No entanto, o endurecimento do material não afetou o aumento da resistência à tração.

Aug 17, 2017

By Carolina Machado de Castro Amaral

A necessidade de treinamento é uma realidade nas indústrias. A qualificação de operadores é importante para garantir segurança e prevenir perdas econômicas. Nesse contexto, o objetivo desse trabalho é desenvolver e avaliar um simulador de treinamento de operador. O estudo de caso é um moinho vertical, comumente utilizado na indústria de cimento. Nessa direção, passou-se pela construção de um supervisório, pela modelagem e simulação dinâmica de um moinho vertical e, por fim, pela elaboração e execução de um treinamento. Para tal, foram construídos três cenários de situações anormais, além da consideração da operação normal. Ainda em relação à metodologia, treinaram-se dois grupos de alunos com métodos distintos de ensino: o primeiro recebeu apenas um treinamento teórico, através de uma apresentação multimídia; e o segundo, após esse treinamento teórico, recebeu um treinamento prático, ou seja, do tipo aprender fazendo, a partir do contato direto com o simulador de processos. De modo geral, percebeu-se que o contato com a prática possibilitou um maior entendimento da operação do moinho vertical, do grau de dependência entre as variáveis de entrada e de saída, e das variáveis utilizadas para a recuperação do processo à operação normal, contribuindo ainda para uma maior fixação do conhecimento teórico. Esse trabalho é resultado de uma parceria UniversidadeEmpresa, cujas atividades foram desenvolvidas por um grupo de alunos de graduação em Engenharia Química.

Aug 17, 2017

By Paulo von Krüger

Nas condições adversas do mercado atual, aliadas à exacerbada competição é uma questão de sobrevivência a otimização de resultados. Para tal é imprescindível que os principais insumos, particularmente os mais gravosos sejam criteriosamente selecionados. Os eletrodos de grafite estão entre os itens principais na operação dos fornos elétricos a arco, tanto do ponto de vista técnico, quanto econômico e a escolha correta deste insumo deve contemplar aqueles dois enfoques. Esta escolha se faz dentre as diversas classes, disponibilizadas no mercado: RP, HP, SHP, UHP. O que se pretende no presente trabalho é sugerir uma metodologia que, contemplando o elenco de parâmetros influentes, permita fazer a escolha correta do eletrodo, dentro daquelas classes, tanto sob o enfoque técnico, quanto econômico.

Aug 17, 2017