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By Luis R. Fonseca, C. Raimat, C. Wendeler, A. Sanz

"Rockfall barriers are widely known as proven efficiency element to protect infrastructure by catching the rock blocks in the falling direction and absorbing the energy generated by them.It’s common in the project design phase and during installation, fix rockfall barriers for catch a high percentage of the falling blocks and in many cases consider as valid the solution when the barrier can capture all of them. However, in many cases it’s possible to consider the use of these protections, simply to guarantee a secure shed for the traffic and intercept simply the blocks that theoretically hit the road surface.The results of the high-energy rockfall protection barriers type GBE which protect GC-200 road in Las Palmas de Gran Canaria are shown in this paper.The topographic data should be especially detailed observed and even more if you want to apply the technique of ""shadow zone"" with a flexible gallery system. It should be drawn from detailed topographic maps and drawings (photogrammetric restitution) to the scales 1/1000, 1/500, or 1/200; and it is important not to ignore the presence of vertical cuts, tracks, small slopes that modify the trajectories (trampoline effect, hard points that favor the rebounds) and which are not always presented in the drawings.The ""shadow zone"" is defined as the protected area, located at a lower elevation to the line created by the rockfall barrier to except of trajectories of rocks and free from the influence of the deflection of the system under the maximum energy level for which it was designed (MEL)."

Jan 1, 2015

The first metal-mine accident-prevention course was prepared and published in 1942--45 as a series of seven miners' circulars (Nos. 51-57). The scope of the course has been broadened, revised, and brought up to date, and it is being published as a similar series of seven miners' Circulars (Nos. 51-57, revised) on accident prevention in metal and nonmetallic mines. These circulars are: Accident Statistics (Miners' Circular 51), dealing with general statistics on accidents and injuries at metal and nonmetallic mines, including causes, costs, and the uses of investigations and reports of all accidents.

Jan 1, 1957

By Vernon C. Davis

"SUMMARY AND CONCLUSIONSIn initial attempts to mine taconite by conventional open-pit methods, the material tended to break into tabular blocks that were too large to be handled by conventional shovel dippers and were unsatisfactory in an ordinary crusher feed. A great amount of secondary blasting was necessary, which added considerably to the cost of mining.The Bureau of Mines and others are engaged in studies designed to contribute to the solution of taconite-mining problems. These studies concern problems related to drilling techniques and patterns, types and methods of use of explosives, and other factors relative to effecting maximum fragmentation at minimum cost.This report is concerned with study of the application of shaped charges in drill holes, the effectiveness of shaped charges as compared to capped charges in secondary blasting, and the merits of different drilling patterns and methods of detonation of conventional-explosive charges.Fragmentation of taconite at or near the surface is controlled or strongly influenced by joint and bedding planes. Since all tests in this study were made in a jointed and bedded area, a definite conclusion as to the relative effect of a shaped charge in a drill hole, as compared to a conventional charge at greater depths and tighter ground, is precluded. However, application of shaped charges in primary blasting of taconite appears to be of no advantage.In secondary blasting of taconite, conventional, capped charges produced better breakage than shaped charges of the designs tested.Based on the results of conventional blasting practice in horizontal-, inclined-, and vertical-hole tests, no better fragmentation is obtained from blasting either horizontal or inclined holes, compared to vertical holes.Holes drilled in staggered parallel rows that intersect both series of joint planes at the greatest possible angle, give maximum breakage compared to rows parallel to one of the series of joint planes.Methods of detonation made little difference in breakage; but the millidelay caps produced the best conditions for moving the broken rocks."

Jun 1, 1953

By Frank H. Reed

This report is one of a series written by members of the Solid Fuels Mission to Germany describing wartime developments in the mining , preparation , and utilization of coal . This mission was organized early in 1945 under the auspices of the Technical Industrial Intelligence Committee , which cooperated with a counterpart British committee . The Solid Fuels Mission operated under the direction of a steering committee headed by Dr. C. J. Potter , Deputy Solid Fuels Administrator . The personnel of the mission consisted of H. F. Yancey, in charge , J. W. Buch, Thomas Fraser , L. L. Newman , and L. D. Schmidt of the Bureau of Mines ; H. H. Lowry , Director of the Coal Research Laboratory , Carnegie Institute of Technology; H. J. Rose , Vice - president and Director of Research , Bituminous Coal Research , Inc .; and F. H. Reed , Chief Chemist , Illinois State Geological Survey . Over 50 reports were written by the members of the Solid Fuels Mission . These , together with microfilms of supporting data obtained in the course of the investigations , are on file at the Bureau of Mines , Washington , D. C. , where they are available for public examination . The Office of the Publication Board in the Department of Commerce is prepared to furnish photolith copies , photostats , or microfilm reproduction of all declassified reports . A Bibliography of Scientific and Industrial Reports is issued weekly by the Department of Commerce , Office of the Publication Board , and is sold by the Superintendent of Documents , Government Printing Office , Washington 25 , D. C. , on a subscription basis . An initial payment of $ 10 will provide for approximately 9 months , and subscribers will be notified when additional remittance is necessary . All subscriptions will begin with volume 1 , No. 1 , unless ordered otherwise . The Bibliography, covers all materials and subjects and gives instructions for obtaining the desired items . The reports of the Solid Fuels Mission relate to the following general subjects : Mining methods in the Ruhr district of Germany , with special reference to mechanical cutting and loading equipment , pneumatic packing , and Diesel mine locomotives ; activities of industrial research laboratories supported by the German coal and coke industry ; coal preparation in western Europe ; low- temperature carbonization processes ; metallurgical coke from

Jun 1, 1948

These inspection standard have been prepared for use in the Federal inspection of strip mines producing, bituminous coal, anthracite, and lignite. This circular is a revision of the Safety Code for Strip Mining, which was prepared by the Bureau of Mines and employed as a guide for Federal inspectors. Numerous changes have been made in the original code to keep the in step with improvements in the industry. With continuing changes in mining methods and facilities some of these standards may become inapplicable and further revision may be advisable. Therefore, questions regarding these standards, and suggestions regarding new standards should be brought to the attention of the Bureau of Mines. Few States haves laws pertaining to strip mines, but where such laws do exist it is possible that some of the standards may conflict with them. In cases of conflict, the intent is not to advocate noncompliance with State laws, but to suggest reconsideration of such laws or safety orders.

Jan 1, 1946

By T. M. Romslo

The Lake Shore property, located in the early 1880's, contains copper-bearing deposits that have been developed by surface excavations, underground workings, and churn-drill holes. Operation of the property ended in 1929 with a total recorded production of 280,000 pounds of copper. The property is near the foot of the Slate Mountains, which are made up mainly of probably the Pinal formation of pre-Cambrian age. In the mine area there are a few outcrops of granite, which is exposed over a large area east of the property. Other outcropping rocks on the property are limestone, quartzite, and diabase. The limestone and quartzite probably are the Mescal and Troy formations of pre-Cambrian and Cambrian age, respectively. The predominant copper mineral is chrysocolla, a hydrous silicate that occurs mainly as fracture filling in bedded schist. It is also, the principal copper mineral in the shear zone at the schist-granite contact and in limestone southeast of the main workings. Investigation of the Lake Shore property by the Bureau of Mines included both topographic and geologic mapping, exploratory drilling, and metallurgical test work. One diamond-drill, hole and five churn-drill holes were completed for a total of 2,872.5 feet. Drilling started January 19 and was completed May 13, 1949.

Jan 1, 1950

By N. A. Sareyed-Dim

Nickel ores may be classified into two major categories : sulphide ores, and oxidized lateritic ores, these latter containing nearly 80% of the known reserves of the metal (1). Two types of lateritic ores are recognized; ores high in iron but low in magnesia and silica are known as "limonitic", while ores low in iron but containing high percentages of magnesia and silica are called "silicate" (see Table I). Sulphide ores can be beneficiated readily by conventional ore dressing techniques and the technology for nickel recovery from such ores has been well tested in a number of commercial processes (1-4). Unfortunately, no economically viable process for the concentration of nickel from low-grade deposits has yet been developed, and so only the high grade ores are able to be worked profitably. Silicate ores have been treated pyrometallurgically for the production of ferronickel (2) (3) (5); limonitic ores have been processed hydrometallurgically to produce nickel metal (2) (3) (6) (7).

Jan 1, 1975

By C. Edwards

ABSTRACT: Milling operations in northern Saskatchewan’s Athabasca Basin have produced uranium continuously since 1975. During that period, the Athabasca Basin has been one of the world’s premier uranium camps, yielding more than 660 million lb (299,370,964 kg) of U3O8. In this paper, the author describes former and current milling operations and discusses why and how the milling process has changed and developed over the past 35 years. The author’s considerations for the future of uranium extraction in the Athabasca Basin conclude the paper.

Jan 1, 2012

By G B. Smith, D Hillier, T Gibbons, D B. Donato, M D. Adams, S Davies, R S. Schulz

Responsible management of cyanide solutions and tailings on gold processing plants worldwide is an important aspect to these operations and is regulated via guidelines provided by the International Cyanide Management Code, an industry initiative designed to minimise cyanide risk to operators and the environment. Here we demonstrate the unprecedented causal relationships surrounding the saline (>14 000 mg/L total dissolved solids - TDS) and hypersaline (>50 000 mg/L TDS) cyanide solutions in gold plant tailings in the Central Goldfields of Western Australia, resulting in zero wildlife mortalities on three sites over the study period of almost one year. Wildlife interaction and ingestion is significantly lower than that experienced at other gold mine sites, with more rapid degradation of weak-acid dissociable (WAD) cyanide within the tailings storage facility (TSF). A rigorous chemical sampling using a novel æminimal accessÆ robotic sampler device and wildlife observation exercise was carried out at two hypersaline mine sites: Barrick Kanowna Belle (BKB) and Gold Fields St Ives (GSI) and one saline site, Barrick Granny Smith (BGS). The data was compared with available reported chemical sampling and wildlife observation data from a previously operational fresh water site (<2000 mg/L TDS) that had experienced wildlife mortalities, Case Study D (CSD). The comprehensive body of work, along with cyanide degradation test work carried out in the laboratory, was analysed via hypothesis development and testing, causation analysis and dynamic chemical modelling. The non-mortality effect on these sites appears to hold over a further four years of routine wildlife and cyanide monitoring by site personnel. This study has helped these three mine sites achieve and maintain full Compliance Cyanide Code status over a significant period while removing the need for operating the detoxification plants they would otherwise have required.CITATION:Adams, M D, Donato, D B, Schulz, R S, Smith, G B, Gibbons, T, Davies, S and Hillier, D, 2013. Hypersaline-induced reduction in cyanide ecotoxicity at gold operations, thereby obviating detoxification plants, in Proceedings World Gold 2013, pp 489-502 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By The Staff

THE gold mining industry in Canada is today the most important stabilizing influence in the country. This factor was brought out particularly during the 'depression' years, when steady employment was given to men in that industry and the monies spent in supplies and power in turn benefited the country to a great extent. At the same time, a commodity was produced which was saleable in any market of the world, thus maintaining Canada's credit in foreign markets and keeping her trade balances equalized. We have a vast area known as the Precambrian Shield. The agricultural possibilities of this area are practically negligible and it will depend entirely upon the mineral and forest resources to make this district an economic factor in the life of Canada. To date, from the mineral point of view, we have been highly successful. There are, however, still vast areas to be explored. It is tedious and laborious work, entailing great individual hard-ships and the expenditure of much energy and money. During my thirty years' experience in the search for, and operating of, gold mines, I have come to the conclusion that although individuals may give all their time, energy, and money, Governmental assistance is absolutely necessary in the development of hydro-electric power sites and roads. The Governments, to date, have given splendid co-operation along these lines, but in order that this great industry may go ahead they should continue their good work and, if possible, give greater relief from taxation to mines situated at a considerable distance from the railway.

Jan 1, 1938

This specification, along with the drawings, encompasses all designs, materials, products, accessories, tools, equipment, services, transportation, labor and supervision, installation techniques, and testing procedures required for the installation of soil nail excavation support or earth retention systems. This is a Guide Specification designed to assist in the development of project specifications for soil nail excavation support and earth retention systems. This Model Specification is based on generally accepted industry standards but may require modification by the specification writer to accommodate unusual and/or unforeseen site and subsurface conditions and the particular circumstances of the project. Care must be taken to avoid internal inconsistencies. It contains language allowing for a Contractor-Designed Soil Nail Wall, which would be removed if the design is provided by the Owner (e.g. See Sections 1.2 and 4.1).

Jan 1, 2010

By Albert W. Deurbrouck

This report describes preparation characteristics of significant coalbeds in Tazewell County , Va . In 1961 Tazewell County produced 933,110 tons of clean coal from six coalbeds ; the Lower Banner , Raven , Jawbone , Upper Seaboard , and Pocahontas No. 3 and No. 5. Samples from all of these beds , except the Lower Banner , were included in this study plus a sample from the Pocahontas No. 4 bed . Of the samples collected , only one would require upgrading to be of metallurgical quality . The coals ranged in rank from high- volatile -A to low- volatile bituminous .

Jan 1, 1963

The first metal-mine accident-prevention course was prepared and published in 1942-45 as a series of seven miners' circulars (Nos. 51-57). The scope of the course has been broadened, revised, and brought up to date, and it is being published as a similar series of seven miners' circulars (Nos. 51-57, revised) on accident prevention in metal and nonmetallic mines. These circulars are: Accident Statistics (Miners' Circular 51), dealing with general statistics on accidents and injuries at metal and nonmetallic mines, including causes, costs, and the uses of investigations and reports of all accidents.

Jan 1, 1955

By BUREAU OF MINES

In July, 1918, the attention of the Secretary of the Interior WItS called to the rapidly increasing cost of producing gold and the declining output of that metal in the United States. Realizing the importance of the gold-mining industry, the Secretary appointed a. committee, consisting of Hennen .Iennings, chairman, J. H. Mackenzie, and Charles Janin, of the Bureau of Mines, and H. D. Me- Caskey and F. L. Ransome, of the United States Geological Survey, to,make a thorough study of the gold-mining situation in the United States. The study was to cover the increased cost of recovery and the decreased output of gold, and to consider the different measures that had been proposed to relieve the industry and stimulate production. This report embodies the results of the investigation and study made by the committee. The report presents statistical data compiled from various sources, showing the production of gold in the United States and other countries, with comparative figures for coal, iron, and other mineral products, and describes the sources and distribution of gold output in the United States. It discusses the relation of gold' production to finance and credit, the causes for the decline in gold output, and measures for the relief of the industry. The Interior Department publishes this report in the belief that the widest publicity possible should be given the findings of the committee in order that attention may be directed to the serious conditions revealed therein, and in the hope that wide discussion of the subject may result in some action being taken that will aid in upholding the gold standard ,and the gold industry.

Oct 30, 1919

By Barbara Mazzini Loureiro

As placas de circuito impresso (PCI) são materiais heterogêneos e sua composição pode variar em função do ano de fabricação, tecnologia empregada, propósito de utilização, legislações vigentes e país de origem, entre outros. Essas características interferem diretamente no valor econômico agregado a estes resíduos, pois dependem da composição dos mesmos, de tal maneira que as empresas recicladoras tomam como base essas informações no momento da aquisição da sucata. Assim, a classificação e caracterização de PCIs é de suma importância para o mercado de reciclagem de resíduos eletroeletrônicos. A fim de alcançar este objetivo foi realizada cominuição em moinho de facas utilizando grelhas com abertura de 9, 6 e 3mm. A etapa de caracterização incluiu ensaios de digestão em água régia, perda ao fogo, análises química quantitativa por ICP-OES e MEV/EDS. Verificou-se que o lote de PCI estudado possui 39,5% de material cerâmico, 34,5% polimérico e 26 % metálico. A porcentagem em massa de cobre na placa é de 14,28%, de ferro 3,73%, de ouro 0,012% e de estanho 1,29%. O lote não é lead free e é multilayer com quatro camadas de cobre.

Aug 8, 2018

By T Salman

The construction and use of the B.E.T. (gas adsorption) apparatus is described. Examples are given for the determination of large and small surface areas using nitrogen and krypton. Introduction A NY study of the milling of ores from crushing to grinding, classification, and concentration and finally dewatering of the products involves solid particles which are either in contact with a gas or a liquid phase. The surface area of the solid and its characteristics constitute important parameters in all mineral dressing operations. The success of any particular operation is dependent on the interaction of the surface of the solid particles with the gas or the liquid phase. Particle size and specific surface (surface area per unit weight) continue to be important parameters in the flotation research associated with the adsorption of collector molecules or ions on mineral particles, as in the early years of mineral dressing research (1). In order to understand the mechanism of the flotation process, it is essential that the surface properties of the adsorbent be known.

Jan 1, 1965

By Jorge Alberto Soares Tenório, Romano Espinosa, Felipe Fardin Grillo, José Roberto de Oliveira, Denise Crocce

"The aim of this work was evaluation of the recovery of Zn and Fe of the EAFD added to the hot metal in the form of briquette at temperature of 1500°C. The EAFD was agglomerated by cold briquetting and introduced in the hot metal. This study utilized a bench-scale equipment to melt, during this process to kept a flow rate of inert gas above the bath. Were collected periodically metal samples and the samples were analyzed for determination of the content of total silicon and carbon by chemical analysis. Zinc oxide, zinc ferrite and other oxides were reduced and were volatized and collected by a cleaning system of dust (baghouse) located on top of the oven. More than 98% of iron were recovered from EAFD during the test. It was possible to produce a dust containing about 68% zinc by means of adding of EAFD.IntroductionIn the first semester of 2010, steel production was about 706 million tons, 27.9 % more than in the first half of 2009. Not a significantly increase if 2010 data is compared with the first semester of 2007 (only 7.2 % higher), before the world’s economic crises. Steel production is divided into two main routes. The first one, and most used, is the Basic Oxygen Furnace Process (BOF process), which in 2008 accounted for approximately 67.1 % of steel production. The second route is carried out in the Electric Arc Furnace (EAF) that in 2008 represented 30.6 % [1 ].Electric arc furnace dust (EAFD) is a solid waste generated during the steel making process. It is classi?ed according to NBR 10004 as dangerous solid waste-class I, because the elements Pb e Cd leach in water exceeding the maximum limits permitted by the NBR 10004 [2 ]."

Jan 1, 2012

By George W. Bain

The area in Quebec immediately north of the Ottawa river is underlain by a large area of granite gneiss intruded in lit-par-lit fashion into Grenville sediments and low silica intrusives of the Buckingham Series. This complex of metamorphic rocks is intruded by a much later magma found, chiefly, as a very large stock about 20 miles in diameter and extending from Brownsburg to Grenville, and as dykes and small outliers at various places adjacent to its outer margin. 1A similar stock at Rigaud, Quebec, is situated south of the Ottawa river and has been described by O. E. Le Roy. The earliest representatives of the later magma are a series of granodiorite dykes characterized by abundant hornblende, along with primary magnetite and subordinate sulphides scattered as roundish grains through anorthoclase and aligoclase feldspars and subordinate quartz. The rock is found as narrow dykes and shows no prominent secondary structures, either in the field or in thin sections under the microscope.

Jan 1, 1926

By Claudio Rocha Rosales

"Peñoles is a mining group with integrated operations in the smelting and refining of non-ferrous metals, and is also a chemicals producer. Peñoles is the world’s foremost producer of refined silver, metallic bismuth and sodium sulphate and is the leading Latin American producer of refined gold, lead and zinc. The Met-Mex Peñoles Zinc Plant commenced operations in 1973 with an annual production capacity of 105,000 t/y. Year after year the production has been increased, and at present, the production capacity is 240,000 t/y. In this paper, the leaching process,particularly the operation of the jarosite circuit is reviewed ,specifying process improvements to treat high iron calcines.INTRODUCTIONThe purpose of the leaching process is to recover the metals, mainly zinc,through a series of extraction stages with sulphuric acid solutions, which progressively increase the zinc recovery. After the series of acidification stages,the solution, which is rich in iron, is sent to the jarosite circuit to separate the zinc from the iron (Garcia & Valdez, 1996).The first step of the leaching process is the neutral leach circuit which produces a zinc sulphate solution that is sent to the purification section for the removal of impurities such as cadmium, cobalt and copper, after this solution is sent to the tankhouse to feed the electrolytic cells."

Jan 1, 2016

By Toshio Suzuki, Machiko Ode, Won Tae Kim, Seong Gyoon Kim

"The Ostwald ripening and growth and coarsening of the secondary dendrite arm are studied using a phase-field model. The phase-field parameters are obtained at a thin interface limit proposed by Kim et al. In Ostwald ripening analysis, the difference of the concentration due ·to· the curvature effect is shown. The third power of the average particle radius Rav is proportional to time and the ripening constant shows a good agreement with the value by Deppers et al. The particle radii distribution shows the transition behavior to attain a self-similar stationary shape. The growth and coarsening behavior of the secondary dendrite arm is also analyzed using a phase-field model. The estimated arm spacing and its dependence on time are in good agreements with experimental data.IntroductionThe ripening or coarsening process controls the microstructure during the late stage of solidification. The ripening phenomena are recognized firstly by the Ostwald [1]. The first quantitative analysis for the Ostwald ripening in the limit of vanishing solid fraction was provided by Lifshitz, Slyozov and Wagner (LSW) [2,3]. In their study, that the mean radius grows proportional to the cubic root of time and the size distribution of precipitations shows a ""self-similar"" shape are shown. Most of the studies for the Ostwald ripening confirm or predict these two general rules above. In case of finite solid fraction, the general rules are observed but the ripening constant is larger and the self-similar shape is wider than the LSW prediction respectively [4-6]. To analyze· the high solid fraction system, the theories that consider the solute field correlation are proposed [4,7-8]. In the theory, however, since the particle is treated as the point, the effect of the concentration field deviation from the monopole field should be taken into account. Recently the numerical simulation, in which not only diffusive transportation of solute but also convection effect is considered, has been done using a phase-field model [9]."

Jan 1, 2000