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By K. N. Han, N. S. Kim, H. Yoon, J. S. Sohn

The leaching behavior of silver and silver oxides in ammonical solutions has been studied. The current study is concerned with an effective recovery of silver from secondary sources such as spent silver batteries. Silver associated with these batteries appears in various forms including metallic silver, argentous oxide, Ag2O and argentic oxide, AgO. The leaching behavior of metallic silver in ammoniacal solution has been studied using an electrochemical mehtod. Oxidants used in this study include hyperchlorite, hydrogen peroxide, bromine and iodine. Results on cyclic polarization and Tafel plots on the silver anode in ammoniacal solutions are presented and the results are discussed. The dissolution rate of metallic silver in ammoniacal solutions is also compared with those of silver oxides.

Jan 1, 2002

By Henry P. Chandler

COMBINED sales of abrasive materials in the United States during 1956 increased at about the same rate as the value of the Gross National Product in terms of 1954 dollars,3 which was nearly 3 percent. However, some segments of the industry did not follow the general pattern. Sales of abrasive grinding wheels increased 9 percent in value. Sales of surface-coated abrasives declined 5 percent in quantity hut increased 1 percent in value, Production of crude silicon carbide in the United States and Canada advanced both in tonnage and value, but that of abrasive-grade [ ]

Jan 1, 1958

By E. J. (Kirk) Conway

Thirty-five years ago underground coal mining equipment consisted of simple but rugged machines powered by electric motors and hydraulics. The machines were maintained by maintenance personnel armed with a basic knowledge of hydraulics, electricity, and mechanical design. Over the years the the machine has been transformed into powerful complex mining systems. The maintenance burden has also increased. During this period significant advances have been made in maintainability engineering and system design techniques. Many of these innovations and techniques are applicable to the design of underground mining equipment. The objectives of this project were to; (1) determine the extent to which maintainability design concepts and principles have been applied to the design of underground coal mining equipment, (2) try to assess the impact of equipment design for maintenance on productivity and safety, and (3) develop a maintainability design guideline to enhance the design of new or rebuilt equipment. An equipment design review was completed at ten operational coal mines. Interviews were also conducted with mine management, safety, and maintenance personnel to identify machine specific design advantages and problems. Visits were also made to six original equipment manufacturers to discuss the design of their equipment for maintenance. Volume I presents an overview of the protocol used and a summary of the findings. Volume II includes the maintainability design guide for underground mobile mining equipment.

Jan 1, 1989

By Elmer W. Pehrson

Minerals have played a prominent role in the affairs of man and nations since time immemorial but with the advent of the industrial revolution, expanding use of the products of the mineral kingdom became synonymous with the material progress of mankind. Individuals and business groups have recognized this fact so have been aggressive in searching for and utilizing mineral resources, with notable success. Indeed, their achievements are primarily responsible for the present Machine Age. On the other hand, until recently the body politic has failed to grasp fully the essentiality of minerals although, at times, access to mineral supplies has been an important factor in the political maneuvers of nations. This chapter is concerned primarily with the broader political and economic relationships of mineral resources to the world economy, and with the internal and external actions of nations in the field of minerals. Many factors that condition the mineral economy of regions and the world as a whole, influence the internal and external affairs of individual nations. The more important of these are: 1. The nature of man's dependence on minerals. 2. The problems resulting from the unique characteristics of mineral occurrence. 3. Geopolitical concepts. 4. Minerals and world power. Actions of individual nations affecting their mineral economy seek two basic objectives: 1. Attainment and maintenance of prosperity. 2. Military security. Other objectives may be cited but on careful analysis they become integral parts or extreme phases of the two points noted above. For example, the twentieth century aggressions of the USSR, Germany, Italy, and Japan might be considered as direct bids for world power but they also can be interpreted as exaggerated or mistaken efforts toward military security and peacetime prosperity. Similarly, trade barriers, nationalization of industries, foreign exchange manipulations, taxation, monopolistic prac-

Jan 1, 1964

By Pedro Vargas Gálvez

El presente texto señala la metodología de selección del software de mantenimiento respecto a este mismo y a la Planta. Para ello, se detalla las condiciones que deberán considerarse en la Organización de Mantenimiento y la aplicación del Software de Mantenimiento MP2 a una empresa. Asimismo, se presenta el Plan de Implantación, los inconvenientes que se han encontrado así como los resultados obtenidos por la utilización del Software MP2.

May 25, 1998

By Patrick J. Hannigan, William H. Walton, Ryan C. Rusk, Van E. Komurka

"The project consists of a 33-story building with two levels of below-grade parking across the entire building footprint. Timely and cooperative teamwork among the owner/developer, geotechnical engineer, testing agency, structural engineer, construction manager, and pile-driving contractor resulted in an efficient, costeffective, high-capacity driven-pile foundation on a constrained urban site with significantly variable subsurface conditions. Design objectives included utilizing the highest allowable pile loads reasonably installed from a drivability perspective, using readily available equipment. A pre-production test program was performed on 16-inch-diameter (406-mm-diameter) steel pipe piles, driven closed-ended and subsequently filled with concrete. The test program included dynamic monitoring of 10 piles during installation, and of select piles during long-term restrike testing with a drop hammer, with one instrumented static load test. CAPWAP® analyses were performed on both end-of-initial-drive and beginning-of-restrike dynamic test records. The site exhibited significant soil set-up, even after relatively short wait times. Testprogram objectives included characterizing set-up profiles. A design set-up profile was used to develop depth-variable driving criteria for both 500- and 600-kip (2,224- and 2,669-kN) allowable load piles. Test program results permitted more-accurate reduced capacities to be assigned to damaged piles, and to piles which experienced practical refusal. These more-accurate assigned reduced capacities decreased the number of replacement piles required by 50 percent, saving both time and cost.PROJECT DESCRIPTIONThe project, located in Milwaukee, Wisconsin, USA consists of a 33-story mixed-use residential building with two levels of below-grade parking across the entire site footprint. Column service loads range from 1,400 to 4,200 kips (6,228 to 18,683 kN). The project is located immediately adjacent to an existing two-story masonry retail building with a partial basement, supported on shallow spread-footing foundations.Subsurface Conditions – The generalized soil conditions are presented in Fig. 1. Site grades were relatively level, with a ground-surface elevation of approximately +53 feet (16 m), Milwaukee City Datum (“MCD”). Fill material from previous construction was encountered to approximate Elev. +33 feet (10 m). Below the fill, medium dense silty sand, to silt with sand, was encountered to approximate Elev. +23 feet (7 m). Underlying deposits consisted of lean clay, with undrained shear strengths ranging from approximately 1,000 to 3,000 pounds per square foot (psf) (48 to 144 kPa). Silty sand, to silt with sand, exhibiting increasing relative density with depth, was found below the lean clay to approximate Elev. -92 feet (-28 m), where hard lean clay (glacial till) with undrained shear strengths in excess of 5,000 psf (239 kPa) was encountered. Borings did not extend below Elev. -103 feet (-31 m)."

Jan 1, 2017

By R. M. Corn

The Non-Time Critical Forest service CERCLA Action at Mansfield Canyon, Santa Cruz County, Arizona designated previous locators of unpatented mining claims as owners/operators of the Hazardous Waste Facility, retroactively liable for all reclamation costs including reclamation of mines acquired by the Forest Service. The CERCLA Action is based on non-existent tailings, a non-existent permanent resident, inaccurate and unreliable data and did not review or consider prior USGS and USBM data. The consequences of the Forest Service action include(1) reduced exploration, (2) loss of credibility, (3)public disillusionment and distrust.

Jan 1, 2000

By Peter A. Anderson

Innovative solution management is being used at Coeur-Rochester Inc. to increase bullion production and decrease overall costs. New operating programs call for reduced solution application rates to the heap that increase pregnant stream values at a lower and less costly plant flow rate. Silver and gold extractions are equal regardless of leach solution application rate. Solar heating is used in the summer months to increase the core temperature of the heap for use in the winter months to enhance the silver extraction rate. The Coeur-Rochester silver and gold mine, located in central Nevada, is an open pit, heap leach operation that has been in production since late summer of 1986. The facility produces about 15.4 kt/d (17,000 stpd) of -13 mm (-0.5 in.) ore to a leach area consisting of more than 37 hm2 (4 million sq ft) of 80 ml HDPE liner. Crushing is accomplished with a 1220x 1520-mm (48- x 60-in.) jaw crusher. This is followed by a single 2.1-m (7-ft) standard cone crusher and is completed with four 2.1 m (7 ft) short-head cone crushers. Agglomeration is not required for the crushed ore, which contains less than 10% -75. µm (-200 mesh) material. The ore contains 53 g/t (1. 55 oz per st) silver and 0.377 g/t (0.011 oz per st) gold. It is end dumped over previously leached material, leveled, and then ripped with a bulldozer. Drip emitters at 810 mm (32 in.) spacings on 910 mm (36 in.) centers are used to apply barren solution to the heap. A portion of the emitter lines are buried I m (3 ft) deep during the winter months and are placed on the surface the remainder of the year. The leach solution contains 0.75 g/L (750 ppm) sodium cyanide solution at a pH of 10.5 - 11. Dissolved oxygen averages 8 ppm in the pregnant solution. Cyanide consumption for the ore to date is just under 0.2 kg/t (0.4 lb per st). The pH control is accomplished by adding I kg/t (2.0 lb per st) 0-10 mm (-0.4 in.) pebble lime to the ore at the tertiary crusher. The pregnant solution is processed by a conventional closed circuit Merrill-Crowe system. The pregnant solution is clarified through three 158 L/sec (2500 gpm) US Filter Auto-jet clarifiers. This is followed by deareation through a

Jan 1, 1989

By W. G. Dallas

The social and environmental problems presented by the location of a large zinc/ lead ore body within one mile of a thriving town are described. The development problems are social, involving the education of the in habitants , and environmental, requiring the development of a planning strategy and the evolution of a baseline and post -operational monitoring system. The necessity for an environmental-impact assessment and a thorough baseline study is emphasized. The continuing psycho-social consideration of community reaction is advocated.

Jan 1, 1977

By Rubén Céspedes

El carbón es un combustible utilizado en la industria del cemento -en tanto fuente de energía calorífica para el uso alternativo o combinado del carbón. Por ello, el presente texto señala el empleo del carbón en la industria minera a través de un estudio de factiblidad que indique la rentabilidad del cambio y sus aspectos como características del carbón a utilizarse, innovaciones a equipos a montar y la influencia del carbón a utilizarse, así como se plantea la conversión del petróleo al carbón

May 1, 1985

By David P. Reddick

Economics is a social science dealing with the allocation of scarce resources. In modern times the “science” was identified by Adam Smith in his book, The Wealth of Nations, written in 1776. Mr.Smith, highly influenced by the Mercantilists of the 17th and 18th centuries, identified the “Invisible Hand” which would lead every individual to pursue selfish rewards in purchasing goods. He speculated these selfish motives would result in the best good for all. Price would be determined by barter, at a point where self-centered customers and vendors were mutually satisfied. Today, Smith’s theory is known throughout the world as “Capitalism” but most often termed “Free Enterprise” in the United States.

Jan 1, 1992

By G. Bezuidenhout, N. C. Steenkamp

Buying centres are the first point of contact that determines whether ore will be considered as having sufficient provenance to be considered ethically sourced. The information that needs to be captured on the blockchain platform ranges from reports on in-loco inspections and audits of mining and purchase sites. This will guide passive and active monitoring of mining activities, trade-offs for identification systems, including biometrics for the registration of artisanal sellers, scrutiny on the selection of security measures and companies for buyer centres and stockpiling warehouses, evaluation of active and passive infrastructure security, and remote monitoring applications. Assistance with selection and training in geochemical testing instruments to determine the grade of ore material or concentrates and sorting, on-the-ground investigations, guidance on monitoring methods from stockpile and packing area along the transport route to the final destination are required.

Jan 1, 2023

By Maureen Jensen

For mining companies looking to establish a strong North American presence, raise their profile or finance and position themselves for future growth, there is no other destination in the world that can offer a mining company the same opportunities as Canada whether you are an established blue chip or promising junior. Despite historically poor world commodity markets and shaky investor sentiment towards junior explorers caused in part by fallout from the high profile Bre-X fraud, Canada continues to shine as the undisputed mining finance capital of the world. Our natural riches and mining history go a long way to explain Canada's international prominence in mining finance. Canada has actively created and maintained one of the most integrated national frameworks to support mining ventures of all kinds. Our diverse industry, from one-person grass-roots explorers to mining industry giants, is one of our main strengths whether your company is Canada-focused or internationally active. The mining industry continues to be a vital contributor to the Canadian economy, contributing $26.2 billion in 1997 or 3.8% of national GDP, and is the second largest earner of foreign exchange. Industrial mineral companies are a very important part of this strength. These companies require a continuing access to capital to ensure that they can continue to compete and the globalisation of the Canadian mining industry has affected this industry just as much as it has affected every other industry in Canada.

Jan 1, 2001

By Bruce McDonald

This report contains the findings of a study to perform a task and skill analysis of roof-bolting operations, with respect to the operational training requirements and to prepare detailed recommendations for the operational training system. The extent of the problem was determined by visiting underground coal mines, interviewing training and safety personnel, observing and interviewing roof-bolter operators, and reviewing present training programs and facilities. In conjunction with the mine visits an extensive literature search was conducted with emphasis on training, mine safety, and accidents involving the roof-bolting operation and roof-bolter operators. A number of training programs and training devices were considered resulting in the development of a recommended training program including training devices to be used and establishing training objectives.

Jan 1, 1977

By Lewis M. McNay

The Bureau of Mines located and examined 292 burning coal refuse banks throughout the Nation's coal-producing regions in 1968. These coal waste fires, extending over 3,200 acres, produce poisonous, acrid gases and particulate matter that pose a threat to health and safety in the surrounding areas, damage vegetation, and cause the deterioration of nearby structures and buildings. Methods of extinguishing coal refuse fires are discussed, and an approach to eliminating future occurrences of these fires is presented.

Jan 1, 1971

By D. Randolph Berry

Foster-Miller Associates has developed a set of guidelines to permit hoist manufacturers, mine owners, and MESA mine inspectors to design, purchase, install or inspect a safe and effective Emergency Escape Hoist, as required by the Coal Mine Health and Safety act of 1969. A series of surveys were carried out to determine: 1. The attitudes and local needs of the MESA District Managers. 2. Current escape hoist installations. 3. Equipment available for future designs. 4. Foreign methods and equipment for mine rescue. From these survey studies, preliminary guideline objectives were developed.

Jan 1, 2012

By O. W. Borgeson, D. K. Honsberger, R. T. Bell

The Scully Mine, situated in the Labrador Trough near the Quebec-Labrador boundary, is one of the world's largest continuous ore deposits. This paper outlines the sequence of the mining operations from the planning stages to the delivery of the ore to the crusher at an average rate of 50,000 tons per day, 7 days per week. The principal equipment required to maintain this production rate includes four 12.\1.1-inch rotary drills, seven 8-cu.-yd electric shovels and a fleet of large haulage trucks. Particular attention is given to grade control, programmed by computer, drilling and blasting techniques and operational aspects inherent with open-pit mining in Canada's North.

Jan 1, 1969

By D. J. Englund, R. A. Davis

"A three-dimensional CFD model of a straight grate furnace for indurating iron-oxide pellets was developed for exploring conditions of furnace operation for fluid flow, heat transfer and reactions. The model includes reactions for natural gas combustion in the gas phase and calcination and magnetite oxidation as well as drying in the pellet bed. The performance of the model was investigated with a series of pellet production rates that included adjustments to the fuel rates to achieve proper induration temperatures in the pellet bed. The model may be used to discover opportunities for process improvement.IntroductionIron oxide pellets are a feedstock to blast furnaces for iron making. Pellets require physical strength characteristics needed to maintain their integrity during storage, handling, transportation and smelting. Pellets are produced from iron ore in a series of mineral processing operations that form wet green balls from slurries of iron-ore concentrate with binders, such as bentonite, and possibly fluxing-agents such as limestone and dolomite. The green balls are dried, fired at high temperature, and then cooled in an induration furnace to achieve the strength and chemical composition required for efficient reduction and slag separation in blast furnaces. Induration furnaces are generally straight grates or grate-kilncooler configurations. These furnaces operate with pellet beds passing through a series of temperature zones to control drying and chemical reactions in the bed.Process air passes through the zones in an overall counter flow direction to the pellets for efficient heat transfer and energy recovery from the cooling stage. Consequently, the zone conditions and the overall furnace performance are highly coupled. Thus, it becomes challenging to predict how changes to any single zone may affect the rest of the furnace. To gain a better understanding of machine performance and coupling, a three-dimensional, steady-state model of a complete straight grate induration furnace was created using computational fluid dynamics (CFD)."

Jan 1, 2015

By J. R. Goode

Up to one half of neodymium and praseodymium production, key ingredients in permanent magnets, is produced illegally. About 60% of cobalt production, critical in lithium-ion batteries and other applications, comes from central African states, and much of it is produced illegally. Tantalum, important in modern electronics, is also primarily sourced from central Africa and, again, much of it illegally. Illegal mineral production, as exemplified here, is often used to fund armed conflict. Furthermore, it is typically conducted with scant regard for human rights and environmental protection. It also leads to depressed prices which in turn limits the possibility of legitimate producers entering the market. Systems of traceability and provenance, along with cooperative supply chain participants can limit the production of illegitimate material and thereby improve conditions in the countries of origin and reduce downward pressure on prices.

By C. Peter Hayes

The world continues to change and with it the supply of minerals and metals, the location of centres of production of primary metal and the increasing levels of metals and materials recycling. New technologies are being developed to meet the ongoing search by industry for lower costs, cleaner production and new markets. To keep abreast with these changes, and to utilise fully, the potential benefits of these technical advances, the industry will need a professional workforce having different knowledge, skills and professional attributes than in the previous millennium. What are these skills and attributes? How to best attract and develop the metallurgists of the future, and provide for the ongoing educational and research needs of the industry?