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By Robert Hopler

THIS paper deals specifically with heading-driving as distinguished from the broader term tunnel-driving. A heading is a pilot or path-finder for the main tunnel. Some headings are complete tunnels in themselves; that is, conditions at times warrant driving a heading the full diameter of the proposed tunnel. A tunnel 10 ft. in diameter might be driven to advantage through a single heading, provided the nature of the material admits, but it usually pays to drive rock tunnels of large diameter through the headingand-bench system. Much depends upon the material, as in soft ground tunnels of much larger diameter are driven in a single heading.

Jan 1, 2010

Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen. The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a three-dimensional repeating pattern. This group of minerals has shaped human history since the beginning of civilization. From the sand used for making glass to the piezoelectric quartz crystals used in advanced communication systems, crystalline silica has been a part of our technological development. Crystalline silica's pervasiveness in our technology is matched only by its abundance in nature. It's found in samples from every geologic era and from every location around the globe. Scientists have known for decades that prolonged and excessive exposure to crystalline silica dust in mining environments can cause silicosis, a noncancerous lung disease. During the 1980's, studies were conducted that suggested that crystalline silica also was a carcinogen. As a result of these findings, crystalline silica has been regulated under the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard (HCS). Under HCS, OSHA regulated businesses that use materials containing 0.1 or more crystalline silica must follow Federal guidelines concerning hazard communication and worker training. Although the HCS does not require that samples be analyzed for crystalline silica, mineral suppliers or OSHA-regulated businesses may choose to do so if they wish to show that they are exempt from the requirements of HCS. Because crystalline silica is an extremely common mineral and the HCS will affect many mineral commodities, it is important then, that there be as clear an understanding as possible of what is and what is not crystalline silica, and where it is found and used, and how it is qualitatively and quantitatively identified. This primer is an attempt to accomplish this in as nontechnical a manner as possible. This primer will examine crystalline silica. Part I will describe, in nonscientific terms, what crystalline silica is and how we come in contact with it. Part" will discuss the regulatory decisions that have created new interest in this ancient and widespread substance and will present a nontechnical overview of the techniques used to measure crystalline silica. Because this primer is meant to be a starting point for anyone interested in learning more about crystalline silica, a list of selected readings and other resources is included. The detailed glossary, which defines many terms that are beyond the scope of this publication, is designed to help the reader move from this presentation to a more technical one, the inevitable next step.

Jan 1, 1992

By P. C. Good

The Bureau of Mines conducted a laboratory investigation of a sinter-leach method to recover aluminum and fluorine from waste carbon potlining residues from secondary cryolite recovery operations in aluminum reduction plants. After removal of carbon by burning, the residue was sintered at 900° to 1,100° C with silica and N2CO3, then crushed and leached with dilute NaOH solution, dilute Na2C03 solution, water, or water containing residual Na2O which remained in the sinter after reaction and decomposition of Na2CO3. Over 90 percent of the contained aluminum and up to 87 percent of the contained fluorine were extracted from this waste product in the form of a mixed alkaline solution. Treatment of the alkaline solution with CO2 yielded a white precipitate containing 89 percent of the original aluminum and 61 percent of the original fluorine as a mixture of synthetic cryolite and alumina, together with a variable excess of soda.

Jan 1, 1969

By Robert D. McKellar, Luke Frawley, Okrasa. Richard

"The resource industries in Canada are facing increasing global competition and stringent environmental regulations. This has made it essential for companies to lower operating costs wherever possible. Electrical energy rep-resents one variable cost that may be better managed and utilized, providing the user with lower operating costs, improved productivity and better yields.The utility industry is also facing changes in the way it must do business. Utilities in North America are facing the prospect of deregulation that will eliminate the monopoly they have traditionally held. This will force them to strive for lower operating costs, to maintain a competitive position and to improve customer ser-vice so as to maintain their customer base.Ontario Hydro has been working with industry for several years. Many opportunities for cost savings have been identified involving energy efficiency, process improvements and the use of new electro technologies. One useful service that the utility can offer industry is to increase the awareness of potential opportunities suited to their operations. This paper will provide an overview of some of the projects that have been implemented and those that are presently being evaluated. An electronic data-base of electro technology applications that is under development will also be described."

Jan 1, 1996

By Robert D. McKellar, Luke Frawley, Richard Okrasa

"The resource industries in Canada are facing increasing global competition and stringent environmental regulations. This has made it essential for companies to lower operating costs wherever possible. Electrical energy rep-resents one variable cost that may be better managed and utilized, providing the user with lower operating costs, improved productivity and better yields.The utility industry is also facing changes in the way it must do business. Utilities in North America are facing the prospect of deregulation that will eliminate the monopoly they have traditionally held. This will force them to strive for lower operating costs, to maintain a competitive position and to improve customer ser-vice so as to maintain their customer base.Ontario Hydro has been working with industry for several years. Many opportunities for cost savings have been identified involving energy efficiency, process improvements and the use of new electro technologies. One useful service that the utility can offer industry is to increase the awareness of potential opportunities suited to their operations. This paper will provide an overview of some of the projects that have been implemented and those that are presently being evaluated. An electronic data-base of electro technology applications that is under development will also be described."

Jan 1, 1996

By X. Cao, H. Huang, Z. Dai

"Crystal phase of copper-containing slag regulation by the slag viscosity, cooling speed and cooling method, where the slag viscosity is related to the temperature and alkalinity. According to the mineralogy properties of a copper-containing slag, experiments of crystal phase regulation and flotation were conducted. When the copper-containing slag that adding a small amount of calcium oxide was cooled slowly at a rate of 3°C/min and about 1050°C n a cinder inclusion system, the viscosity of slag can be remained under 0.25 Pa·S and more than ??% of copper particles that the grain size is larger than 20 ?m in slag. The whole flow of flotation experiment was carried out to recover copper from the copper-containing slag with crystal phase regulating and the copper concentrate grade was ?????%, the recovery efficiency of copper was 94.18%.INTRODUCTIONChina's annual output of copper slag is more than 6 million tons, the current total has reached 80 million tons. It is equivalent to 640 thousand tons of copper metal with the copper grade of 0.82%. Most of the smelting slag were storage. It is not only occupy the land and pollute the environment, but also make a huge waste of resource (Alp, Deveci, & Süngün, 2008; Carranza, Iglesias, Mazuelos, Romero, & Forcat, 2009; Gorai, & Jana, 2003), therefore, it is good way to achieve copper slag resources by the effective recovery of valuable component from copper smelting slag, which is an important measure of the current process of copper smelting slag and implement the central authorities to vigorously develop the circular economy, improve the recycling of resources, increase copper production of intensive development (Zhou, et al., 1994; Zhang, Zhang, & Wang, 2005). Currently, researches on comprehensive utilization of the coppercontaining slag made a much progress (Wei, 2004; Liu, Gai, Yang, Sui, Li, & Fu, 2008; Liu & Zhu, 2008; Zhang, 2010; Sun, Chen, & Tang, 2012; Qin, Wang, Ren, Wei, Peng, & Gu, 2012). Flotation is one of the most effective method to recover the copper from smelting slag, which has the features of low cost and high efficiency (Song & Liu, 2001; Zhang, Wang, & Li, 2012). But the copper particles in the copper smelting slag distribution is very uneven, and the thickness of the material is very serious. The copper content in the micro level is higher, the size of copper sulfide ore is less than 0.043 mm, which leads to the difficulty of the monomer dissociation (Tossavainen, Engstrom, Yang, Menad, Lidstrom, Larsson, & Bjorkman, 2007; Moustakas, Mavropoulos, Katsou, Haralambous, & Loizidou, 2012). In this study, according the process mineralogy of a smelting copper slag, the crystal of smelting copper slag was optimized by controlling the temperature, alkalinity, cooling rate and cooling method, which makes the fine copper mineral particles in the copper slag crystal further, and can be used to meet the particle size requirements of flotation, thereby enhancing the flotation of copper."

Jan 1, 2016

By J. O'Leary, R. Cannell, D. Honsberger

"The Scully Mine deposit lies within the group of metasediments that together comprise the rocks of the Labrador Trough. The ore itself still retains the bedding characteristics of the parent rocks and on this basis has been divided into three main members, namely: Upper, Middle and Lower. The Upper and Lower both show many of the bedding characteristics of the cherty taconites of the northern U.S.A.; the Middle member is a coarse-grained friable specularite rock. The ore minerals are hematite (normally present in the specular variety) and magnetite, although the latter rarely occurs in concentrations greater than 20 per cent. Gangue minerals are quartz and the hydrated iron oxides. Manganese oxides also occur as accessory minerals. The outcrop area of the orebody is in excess of 2 square miles, displaying a complex pattern of faulting and folding, which has been formed as a result of at least two orogenic periods."

Jan 1, 1972

By J. W. Furlan

Due to the time consuming nature of froth testing in a laboratory environment, it is required, due to practical limitations, to develop a method of applying a single set of performance test data (Visintainer & Whitlock, 2012) obtained for a single froth pump at a given speed, to a range of froth pump speeds and sizes, % air contents, and liquid viscosities. Head, efficiency, and flow all vary as functions of both liquid viscosity and air content. As such, it is necessary to develop a technique which can be used to interpolate from existing test data in order to predict froth pump performance for pumps of various sizes running at variable speeds. Details of the technique developed in order to achieve this goal as well as the insights gained from analysis of the resulting regressions are discussed. Additionally, comparisons are made between the performance predictions of this test-derived method and those of the Hydraulic Institute Standard for the effects of liquid viscosity on centrifugal pump performance (ANSI/HI 9.6.7-2010).

Feb 27, 2013

By L. Cheng, Y. Liu, Z. Shen, H. Shang, Y. Li

The pre-concentration process of magnetic coarse particles can discharge waste rock or liberated gangue before milling, which is an effective means to reduce cost and increase the efficiency of the concentrator, but the weakly magnetic ore doesn’t have the effective separation method of coarse particle such as hematite, limonite, ilmenite and so on, Because the composite iron minerals contain both strong and weak magnetic elements, the pre-concentration process cannot be applied, or the existing pre-concentration process has problems of complicated configuration and high operation cost. By researching a new type of external magnetic separation technology, the pre-concentration process of composite iron ore was realised by single equipment, which can have a good recovery rate with simple arrangement. In this paper, the separation principle and structure characteristics of the external magnetic separator were researched, and the magnetic circuit characteristics of the external magnet were analysed. The laboratory tests of vanadium titanium magnetite were conducted, and the test results proved that the external magnetic separator can be applied for the pre-concentration process. The industrial application shows that a product of TFe 24.76% with 90.08% recovery, TiO2 10.10% with 91.78% recovery can be achieved from the feed of TFe 20.67%, TiO2 8.33%. Keywords: Coarse particle pre-concentration, composite iron ore, external magnet, magnetic separator

Jan 1, 2020

By Mazany, M. S.

THE Caletones copper smelter of the Braden Copper Co. is in the " Teniente" mining district about SO km. (49.7 mi.) southeast of Santiago, Chile. From the seaports of San Antonio and Tralparaiso, the property is reached via the Chilean State Railway (66-in. gage) to Rancagua, whence the Braden railroad (30-in. gage) leads to the smelting plant at Caletones, 60 km. away at 5100 ft. elevation, and continues on to the mine and concentrator at Sewell, at 7000 ft. elevation, 12 km. farther into the Andes. The smelting plant was completed and put into commission in February, 1922. At the start, it smelted daily 750 tons of concentrates produced at Sewell from 10,000 tons of ore; later, its capacity was increased to 900 tons of concentrates from 12,000 tons of ore per day; and it is now being increased to 1100 tons of concentrates from 15,000 tons of ore per day. The smelting plant production is governed chiefly by the

Jan 1, 1925

By Linn M. Farish

SOVIET RUSSIA reserves must be stupendous. In 1937 I. M. Goubkin placed the reserves of all categories it approximately 48 billion barren which was about twenty billion horn Is in excel:, of all the oil produced in the world since 1857. It is not unlikely in fact it is probable, that these huge stores of petroleum may ultimately be proven to exist within the present boundaries of the U.S.S.R. The size of the country is almost beyond imagination it is 2.7 times as big as the United States. Great sedimentary basins exist in all its different geological provinces, much of which are entirely untested and barely prospected. Oil in commercial quantities is actually produced from formations in every period from the Devonian to the Pleistocene. In the Emba region alone, 300 salt domes are known with an estimate of 700 still to be found. Only 22 of the 300 have been drilled and all showed oil. Of the 22 domes drilled six are now producing. There are 400 mapped structures reported in Azerbaijan

Jan 1, 1940

By D. Vanin

"Conventional single heading track drifting in the hard rock mining industry has not shown any significant improvements in advance rates, despite the advent of modern track jumbos and igh speed muck handling systems .This paper presents Kiena 's experience in using a 7 ft 2 in. diameter larva Mark 6 Tunnel-Boring Machine (TBM) for driving 6000ft of drift.IntroductionKiena Gold Mines is located about 5 miles west of the town of Val d'Or, Quebec, approximately 300 miles north of Montreal. The mine commenced production in October 1981 and has gone through various expansions of ore production with 287 916 metric tonnes in 1982 to reach 453 800 metric tonnes in 1986.Due to the majority of claims being covered by a lake, a grassroots exploration drive of remote areas of the property was required to allow diamond drilling on a yearly basis. High speed sequential excavation methods (SEM) of single heading drifting in the mining industry has not progressed much in the past 20 years despite the advent of electric-hydraulic jumbos, Haggloader and Hagglund type cars. Certain examples of record SEM drifting advances have been performed in the past but only under very specific ground and cost conditions."

Jan 1, 1987

By Andreas Volkert

Energy efficiency, equipment reliability and cost reduction are of the key factors in any efficient plant. Badische Stahlwerke (BSW) started using its own burner technology in 2001, this was developed by Badische Stahl-Engineering (BSE). Over the past 15 years, Badische improved all aspects of its Virtual Lance Burner (VLB), to perfectly fit all steelmaking requirements. This tiltable VLB was first tested at BSW’s electric arc furnace no. 2 in 2012. Promising results like reduction of refractory wear, energy efficiency, reliability, etc., were obtained. At the same time the existing VLB system was further improved with regards to the design of the water-cooled copper box. Today in 2016 both EAFs at BSW are equipped with the new patented tiltable system and the new copper box design. The paper will describe the results of the past years at Badische, but will also show the performance at other installations.

Aug 17, 2017

By Robert F. Mehl

Jan 1, 1944

By N. Aslin, R. Clark, G. Heferen

The methods of harvesting copper from stainless steel mother plates has been investigated from fundamental and operational experience perspectives. At least five different harvesting techniques have been identified that have different effects on product quality, current efficiency, current distribution, growth morphology and ease of stripping. Each method is examined from fundamental principles to understand what occurs during the harvesting process and why the particular effects are manifested. Experience from plants operating the harvesting method is provided to show that the fundamental understanding is relevant. Best practice harvesting method and harvesting management are described.

Jan 1, 2014

By Robert F. Mehl

Jan 1, 1944

By José Raphael Olegário França

Separação eletrostática é o termo usado para todas as tecnologias de processamento que utilizam forças elétricas que atuam sobre partículas carregadas ou polarizadas sob um campo elétrico estático. O comportamento das partículas depende das suas propriedades elétricas, geométricos e tamanho das partículas. Portanto, a separação de espécies é possível se os parâmetros do campo elétrico e as propriedades elétricas diferentes das partículas são apropriados para o processo. No separador eletrostático de rotor as forças elétricas, combinadas com as forças gravitacionais e centrífugas agem sobre as partículas e são responsáveis pela separação mineral. No presente trabalho as forças eletrostáticas que agem no processo serão substituídas por um modelo de contato de coesão Hertz-Mindlin com JKR. O resultado apresentado, embora com limitações, conseguiu-se fazer uma boa estimativa do processo e alguns dos parâmetros do separador. Com a presente simulação é possível descrever o processo de separação além de permitir a redução de despesas de testes práticos, melhorar a compreensão das relações fundamentais, simular as influências dos diferentes parâmetros e por fim, estimar eventuais aumento de desempenho.

Aug 17, 2017

By E. E. Harton

Bureau of Mines Information Circular 7516, Bibliography of Investment and Operating Costs for Chemical and Petroleum Plants, was published in October 1949 to aid in estimating investment and operating costs of processes for manufacturing synthetic liquid fuels. Development of such processes by the Bureau of Mines was authorized by Public Law 290, 78th Congress. This bibliography included references to and abstracts of publications appearing from. 1930 to September 1948 on all processes in general use in the petroleum refining and chemical industries. Bureau of Mines Information Circular 7705, Supplemental Bibliography on Investment and Operating Costs for Chemical and Petroleum Plants, was prepared to cover the area from September 1948 through June 1952.

Jan 1, 1956

By N. Samman, S. N. Lau

"A series of new, grease-based, solvent free open gear lubricants were developed to meet the demanding service requirements of mining equipment. The use of these products has resulted in better performance under conditions of temperature extremes and in terms of longer component lives. They have gained widespread acceptance within the mining communities for such applications as the lubrication of mining shovels, draglines and ball mills.These products are WHMIS non-controlled and are environmentally acceptable. The benefits and advantages of using this type of product to lubricate mining equipment as well as the field evaluation and experience will be discussed."

Jan 1, 2002

By Andrew B. Cecala

The U.S. Bureau of Mines has designed and evaluated total mill ventilation systems at two different mineral processing operations. Both systems have proven very effective at reducing respirable dust levels throughout the mill in a cost-effective manner. A 25,500-cfm system installed at a clay processing mill provided approximately 10 air changes per hour. This system reduced respirable dust concentrations by approximately 40 pct throughout the mill building. The second evaluation was performed at a silica sand operation. Tests were performed with 50,000 and 100,000 cfm of ventilation to the mill building, corresponding to 17 and 34 air changes per hour. Average mill-wide respirable dust reductions were 36 and 64 pct, respectively. Not only did these systems reduce respirable dust concentrations and increase visibility throughout the mills, they were also easy to install and required minimal maintenance. A total mill ventilation system provides a general purging of the mill air; the system should be viewed as a supplemental technique to assist other dust control systems in operation.

Jan 1, 2010