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By M. M. Fine

In an experimental study by the Bureau of Mines, in cooperation with National Lead Co., the roast-flotation process was found to be an effective means of upgrading certain cobalt-nickel stockpiles. The research was undertaken to determine whether the process could yield an enriched feed, with a minimum cobalt content of 6.0 percent, for the company refinery. The stockpiles (products of the company Fredericktown, Mo., milling operations) were essentially complex sulfides of cobalt, nickel, copper, lead, and iron, 1 sample of which contained 2.84 percent Co and 3.57 percent Ni. After a controlled oxidizing roast at 400° C., laboratory flotation with conventional sulfhydric reagents yielded an enriched concentrate analyzing 9.22 percent Co and 11.43 percent Ni, with recoveries of 84.9 and 85.8 percent, respectively. These are typical laboratory data; other data indicated higher grades were possible but at reduced recoveries. A brief, continuous campaign verified the applicability of the process to the raw material in question but was not continued long enough to establish optimum conditions. As a consequence, the results of the large-scale tests did not equal those obtained in the laboratory but definitely confirm the beneficiation possible from the roast-flotation process.

Jan 1, 1958

By Tobias U. Papst

The German Ruhrgebiet is slowly transitioning into a post-mining state. It has been subjected to industrial-grade hard coal mining operations for more than 150 years. Due to a political decision, German hard coal mining will come to an end in 2018. By then the surface will have subsided up to 20 meters. After all mining activities in the area have ended, there will be no need to maintain the current mine water level. Accordingly, the company operating the last remaining coal mines has decided to let the water level rise to an as yet undetermined level. Alongside other issues that may be caused by rising groundwater levels, the protection of the area?s drinking water supply is of utmost importance. This notion is also represented by European and German law. The primary intent of the applicable laws is to protect the health of the citizenship. This means protecting ground water that may be used by humans from being contaminated by the mine water. This paper outlines the consequences of European and German legislature on mining aftercare using the example of one of Europe?s largest agglomerations.

Jan 1, 2014

By I. H. Redeker

North Carolina is the leading state in the USA in feldspar, mica, and spodumene production. Mixed feldspar, spodumene, mica and quartz are mined from hard rock, open pit deposits and recovered by flotation from the fresh pegmatite type ores. Potash feldspar, mica, clay and quartz are recovered from weathered decomposed pegmatites. The North Carolina State University has a Minerals Research Laboratory in Asheville with trained personnel and flexible pilot plant equipment. The flowsheets for the feldspar, spodumene and mica producing companies and for large phosphate and glass sand flotation plants were developed and tested in Asheville. Examples and problems of pegmatite flotation are demonstrated with flowsheets and slides.

Jan 1, 1981

By Brian McInnes, Joseph A. Sopko, Behzad Khorshidi

"The Port Mann Main Water Supply Tunnel involves a 1km long tunnel beneath the Fraser River from Surrey to Coquitlam, BC. At depths of up to 60 m below ground, the earth pressure reached 6 bar. The tunnel is constructed using an EPB TBM and gasketed precast concrete segmental liner. The tunnel and two shafts were constructed in a variety of soil conditions ranging from soft to stiff clays and silts, to compact to very dense sands and gravels. After approximately 800m of mining, a very dense and highly variable soil group consisting of cobbles and boulders halted the TBM. Several options were considered to stabilize the TBM face so an intervention could be conducted. Although de-watering was considered, there was risk of settlement to the Port Mann bridge piers, which was within 500m of the tunnel. Hyperbarics were also considered, however, the cost, schedule and uncertainty of the work that needed to be done, made it a risky option. Ground freezing by Liquid Nitrogen was chosen as the best solution, which would provide a frozen block around the face of the TBM. A temporary platform on the river was designed and constructed to enable drilling and installation of the freezing pipes and temperature monitoring equipment. The operation required close coordination among the tunnelling, marine and freezing sectors. Following the intervention, the TBM successfully broke through the reception shaft, and the remaining project was completed. This paper describes the design, construction and operational approaches used for the freezing and serves as a basis for future projects requiring expedited ground freezing."

Jan 1, 2016

By Cedric E. Gregory

"A study of model rectangular mine shafts has been made in the wind tunnel, with the aim of reducing air-flow resistance elements to a practicable minimum. An analysis of Table 7 shows an indicated average decrease in resistance of 28 per cent by adopting the over-all modifications involved in the configurations actually tested. Much greater reductions (up to 68 per cent) are indicated by extrapolating beyond the test results directly achieved. Intermediate partial reductions in aerodynamic resistance are shown for individual modifications, such as: (1) about 3 per cent for locating the lagging in the No. 4 (inside flush) position as against the No. 1 position - 8 per cent as against the No. 2 position - and 23 per cent as compared with position No. 3; (2) about 12 per cent for using lagging instead of steel meshwork along the divider separating the skipway from the service compartment; (3) about 14 per cent for using steel gridwork ladder stagings at 3-set intervals instead of similarly spaced wooden stagings; (4) about 12 per cent for using steel gridwork ladder stagings at 3-set instead of at 1-set intervals; (5) about 13 per cent for fitting a streamlined fairing (see Fig. 5) to the upstream face of the skipway divider. Contrary to expectations, an advantage of only 3 per cent is indicated for lagging in the inside flush (No. 4) position over the outside position (No. 1). This slight gain does not appear to warrant the cost of moving the lagging. However, if the lagging is already in the No. 2 or No. 3 position, there is an 8 and 23 per cent advantage respectively."

Jan 1, 1973

By R. F. Abernethy

Analytical results, including ash fusibility data, are presented by the Bureau of Mines for 10 major constituents in coal ash from 373 samples of commercial U.S. coals. Determinations of Si02, Al2O3, Fe2O3, and P2O5 were made by colorimetric methods, Na2O and K2O by flame photometry, Ti02, CaO, and MgO by a spectrochemical method, and SO3 by a gravimetric method. In bituminous coal ashes the silicon, aluminum, and iron calculated as oxides often make up about 90 percent of the ash.

Jan 1, 1969

By E. D. Gálvez, L. A. Cisternas, R. Acosta-Flores, F. A. Lucay

Froth flotation processes are carried out in flotation cells that are grouped into banks, and these banks are interconnected, forming a flotation circuit. A literature review shows the existence of papers related to flotation circuit design based on mathematical programming. However, due to the complexity of solving the mathematical model in most of the work, it is considered that a small number of species is present in the feed to the circuit, which differs from practice. In addition, simple bank models are generally used. This paper presents a methodology for designing mineral concentration circuits that overcomes the problems mentioned. It allows the use of more suitable cell or bank models and the inclusion of several species. The methodology is based on two phases. The first phase identifies the set of optimal structures using discrete values of stage recoveries, solving several mixed integer linear programming (MILP) problems. In the second phase, the optimal design for each of the structures obtained in the previous phase is determined using a suitable model for the recovery at each cell or bank, which results in a mixed integer nonlinear programming (MINLP) model. The design of a copper concentration plant with eight species and the design of a zinc concentration plant with three species and five size fractions by species are used to validate the proposed methodology. The structure of the cells in the rougher and cleaner banks deliver structures that are novel.

By Kenelm C. Appleyard

In introducing to an American audience a description of the work done in dry coal separation in England and in Europe generally, it is perhaps desirable to give a short history of the development outside the United States of the particular processes with which the author is connected, and perhaps to stress a little the differences in the nature of the conditions to be faced. England actually presents one set of problems and the Continent of Europe another, since the character of the coals to be treated is entirely dissimilar, and the attitude of the coal industries towards coal preparation is also dissimilar. England for generations has been working by hand good seams of clean coal of the highest possible quality and has not felt any pressing need to clean its coal. Most Continental countries, however, especially in Central and Western Europe, have been working friable and often very dirty coals for so long that a washery is accepted as a part of the normal equipment of a colliery, with the result that the art of wet washing has reached a high state of perfection, particularly in Belgium and Germany. The advent of machine mining has intensified the problems to be faced in all countries, and in England has been coupled with the working out of the best seams in the older coal fields, thus bringing about the necessity of working thinner and dirtier seams with resultant difficulties as regards marketing the products, while Poland, with clean and well prepared coal, has in recent years been attacking established British markets in Scandinavia. In recent years, therefore, interest in coal preparation has been steadily gaining ground in England, although it has not yet reached Continental dimensions. Broadly speaking, the differences in preparation problems between England and the Continent boil themselves down to one of size. In England, for example, with the exception of the Kent coal field, the proportion of coal of a size less than ? in. to the coal less than 2 in. is very much less than on the Continent, and since the principal difficulties in dry cleaning lie in the fines it is easier to produce good figures on

Jan 1, 1931

By T Clemens, D Trumm

Adopting environmentally acceptable practices in New Zealand is a crucial requirement for mineral wealth development. Recent planned expansions in the coal and gold industry have increasingly placed mining in the media spotlight. A lack of appropriate standard environmental guidelines has resulted in inconsistent responses and assessments of current and proposed mines. These inconsistencies have lead to delays in decisions on developing economic mineral deposits that may have only minor short-term impacts, and have also allowed unacceptable environmental management practices to continue elsewhere. A research collaboration between CRL Energy, Landcare Research, University of Canterbury and University of Otago aims to provide regulator groups and the mining industry with a unified approach to the requirements of the Resource Management Act 1991,the legislation that largely drives the nationÆs environmental policies and guidelines. The tangible outcome of this research program will be water quality and impact management guidelines integrated into a decision-making framework. The result of this unification will assist in the development of viable mineral deposits and minimise environmental impacts. The framework will be derived from a synthesis of three objectives. Objective 1 identifies potential water quality impact. This objective is based on a targeted geochemical study of the lithology and waterways of the West Coast and Southland regions. Objective 2 categorises the degree of impacts on the ecology of receiving aquatic ecosystems and determines the processes that drive aquatic ecosystem recovery. Objective 3 identifies best strategies to sufficiently manage impacted ecosystems, and to prevent future unacceptable impacts. Wide consultation with representatives of the mining industry and regulator groups will occur frequently during the development stages of the framework. It is anticipated that this multidisciplinary approach will provide a robust and coherent, standardised system that will assist in achieving industry and environmental targets.

Jan 1, 2004

The nation of Fiji is located the South Pacific on the æRim of FireÆ some four hours flying time from the eastern sea board of Australia. It is a tourist destination situated on the main route from Australia to the Americas. Fiji is a developing country that has had a fewsetbacks but the country has able, happy people that are very resilient. Most importantly, the country is a safe destination for tourists and businesspeople as the local people are friendly, have good ethics, and most speak English. Fiji is a very willing nation, hungry for knowledge and advancement. The Fiji geological setting on the æRim of FireÆ, that runs from New Zealand across the Pacific through Fiji and on to Papua NewGuinea, has many large deposits of gold and copper. Fiji is an exciting destination for mineral explorers with discoveries of gold, silver, manganese, bauxite, iron and copper. Gold was first discovered in 1921 and the first two mines opened in 1935; one of which was Emperor Gold Mining Company (EGM) the other being Mt Kasi. EGM mines gold on the margin of the Tavua caldera, some 85 km north of the Nadi international airport. EGM has operated continuously for close to 70 years, producing approximately 6.9 million ounces of gold and has an underground reserve of 847 600 ounces with a total mineral resource of 12 335 600 tonnes at 10 g/t (as given in the Emperor Mines Limited Annual report 2003). The mineralisation in Fiji is very exciting and it is common to discover spectacular intersections and outcrops, which are typical for this type of epithermal narrow vein mineralisation, but be aware that the orebodies are variable and not easy to understand.

Jan 1, 2004

The Industrial Minerals div. has been forging ahead in formulating a program for the February Annual Meeting in Los Angeles. Several papers have been listed and more are being worked into the program. For the cement, lime and gypsum part of the sessions, papers on Gypsum in the Aircraft Industry, Geology of San Marcos Island Gypsum Deposit, and Status of New Dry Rotary Blast Hole Drills, are expected. The Chemical Raw Materials sessions will feature a symposium on potash, with 13 papers as the anticipated number to be presented. Airborne and Ground Magnetometer Work has been suggested. Eight papers have been set for Mining Geology, Four papers, Mining Phosphate Rock, Idaho Phosphorous, and Geology of Carlsbad Potash and Geology of Pearlite will be on the program. Sessions on Dimension stone and slate have been tentatively worked out with papers on Geologic Factors Affecting the Dimension Stone Industry of California, A Quarter Century of Granite Quarrying in Massachusetts, Rock Bursting and Other Geologic Problems in the Granite Quarries of Barre, Vt., Quarry Practices in the Indiana Building Stone Industry, Stratigraphy and Composition of the Salem Limestone, and Dimension Stone in the U. S. in 1952. The Rare Minerals Committee is aiming for six papers with two papers now definitely on the program.

Jan 1, 1952

By George H. Holmes

This paper is one of a series being prepared by the Minerals Division of the Bureau of Mines on mining and milling methods and practices at various mines in the United States. It describes such methods at the Caselton mine of the Combined Metals Reduction Co. The Caselton mine and mill are in secs. 28 and 29, T. 1 N., R. 67 E., M. D. B. & M., Lincoln County, Nev., about 10 miles by paved highway south- west of Pioche, Nev. (fig. 1). the history of the district and company This circular summarizos operations, describes physical features, labor and living conditions, the geology, ore deposits, and the ore. Prospecting and exploration methods are outlined, and shaft sinking, drifting and crosscutting, and raising are covered under development methods. In the soction on mining mothods, stoping and slushing are discussed, following which are descriptions of underground transportation, hoisting, ventilation, drainage and sampling, and surveying. The surface and crushing plants are described, and milling practices are presented in dotail with explanation of the filter plant and assay office. Safoty practices and the company organization are described in the concluding sections of the circular.

Nov 1, 1950

By René Winand

Due to chemical and electrochemical behavior of the most common additives in copper electrorefining i.e. gelatine, thiourea and chloride ions, it is essential to simulate as far as possible true industrial practice while performing laboratory experiments. The three additives must be studied simultaneously, and added continuously to the electrorefining cell. Ratio electrolyte volume to cathode area; ratio bleed flow to cathode area; hydrodynamic conditions; residence time of electrolyte in the cell; current density; electrolyte and soluble anode must be as near as possible to industrial ones. Experiments performed in the author's laboratory show that under these conditions, reproducible results can be obtained at normal industrial current density and at high current density as well. Problems are however still encountered when developing a sensor for additives monitoring, due to electrolyte redox potential and to substrate influenced thin layer deposition.

Jan 1, 1995

By M. Jahazi, J. Gholipour

Design and manufacturing of parts using hydroforming process require knowledge about material behaviour and tribological effects during hydroforming. Lubrication is one of the key issues in successfully hydroform the tubes. A Ni-based super alloy tube with 50.8 mm (2 inches) outer diameter and 0.9 mm (0.035 inches) thickness is considered for this research to study the effect of lubricants on the formability of the tubes. Hydroforming of a hollow compressor blade is considered for this project. A combination of press forming and hydroforming is employed to produce the part. LS-DYNA, an explicit dynamic finite element code, is used to model the experiments. Different lubricants are modeled using different coefficient of friction in the model. Predicted results for strain distribution at a critical section of the tube are extracted for each case to evaluate the effect of different lubricants on the process.

Jan 1, 2006

By M. M. Barr

Rapid expansion of the titanium-metal industry focused attention upon ilmenite as a possible substitute for the more expensive and less abundant rutile in producing titanium tetrachloride. Most of the rutile available for this use is imported. Preliminary studies were undertaken to determine the chlorination characteristics of high-titanium slags produced by electric-arc furnace smelting of alluvial Idaho ilmenite at the Federal Bureau of Mines Northwest Electrodevelopment Experiment Station, Albany, Oreg. Low silicon, calcium, and aluminum contents of the slags enhanced their potential value for chlorination.

Jan 1, 1958

By Theodore H. Boggs

The battle of the gold standard is not limited to one country alone, or even to a single group of countries. It is being waged merrily in many important commercial and industrial quarters. Though it is not always a practical issue calling for immediate attention, it is none the less, quite widely, engaging the thought of bankers and other students of finance. The controversy arises, in the last analysis, because of the desire of men to secure a stable currency. There are two ways of restoring a reasonably stable currency system: (1) the re-establishment of the gold standard, or (2) the deliberate and artificial management of a paper currency. Both systems are well known. The gold standard was in use prior to the war in the principal commercial countries. A currency of inconvertible paper has been at times employed in the past in various countries; for example in Britain from 1797 to 1821, and in the United States from 1862 to 1879. The gold standard, as all are aware, implies the selection of gold as the standard of value. The unit of value is a fixed weight of gold and, so long as the standard remains unimpaired, all other means of payment are maintained at a parity with standard gold coins. And gold coins alone constitute the standard money, inasmuch as their value as bullion equals their value as coins. Under the gold standard this would not be true of any other form of money, although all other varieties of money, including bank notes, government notes and silver coins would be freely convertible into gold money. Strictly speaking, the gold standard also implies that the gold money in turn shall itself be freely convertible, through melting, into gold bullion and freely exportable.

Jan 1, 1925

By Eleanor Kentish, Nathan Bond, Edward Batty, Simon Webber, Alan Skarda

"Crossrail is Europe’s largest construction project — a new 100km rail route running through central London. A joint venture of BAM, Ferrovial and Kier (BFK) has constructed the tunnels and escalator shafts at the new Bond Street and Farringdon Stations. The recent trend in the UK industry towards sprayed secondary linings is driven by the potential for significant savings in cost and time. BFK is unique within Crossrail by constructing both sprayed and cast secondary linings. This paper presents a direct comparison between sprayed and traditional cast in situ secondary linings at Bond Street and Farringdon Crossrail Stations. An objective comparison is drawn between procurement and mobilisation periods, production rates, flexibility, tolerances and logistics in the tunnels. The technical challenges surrounding cast and sprayed secondary linings are explored, and recommendations are made of how each method could be improved for future use. INTRODUCTION It is well established that sprayed concrete offers a fast and effective method to seal the face of an excavation. In a relatively short space of time, sprayed concrete can be applied to an open face to support the short term ground loading on the tunnels during construction. Advances in sprayed concrete lining (SCL) technology — such as the use of wet mix processes, improved accelerators, fiber reinforcement, remotely controlled spraying robots, innovative surveying equipment and nozzleman competency schemes — have greatly increased the speed and safety of tunnel excavations using this technique. As a result, design engineers have become increasingly confident to use SCL primary linings as part of the permanent structural lining (Su 2014). Historically, long term ground and water pressure loads have been considered to be carried by the main structural or secondary lining, constructed using cast in situ concrete (Pickett 2014). However, the advances described above have made sprayed secondary linings a viable option, which has already been proven on the A3 Hindhead Tunnel (Arnold 2012). Sprayed concrete secondary linings offer potentially significant savings in cost and time during the construction process. The contractor does not need to procure a bespoke formwork system for each different sized tunnel — the SCL plant required is already on site for the primary lining. Each bay is sprayed with accelerated concrete, becoming self-supporting almost immediately — compared to moving and resetting the shutter, pumping concrete and waiting for it to cure. With sprayed concrete, working sequences and cross sections can easily be changed."

Jan 1, 2016

By Gwenaële Petit, Ulan Massimkhanov, Gilles Joubert

For its Zuuvch Ovoo uranium deposit in Mongolia, Badrakh Energy (partly owned by Orano Mining) is working on the prefeasibility study for exploitation by ISR (in situ recovery). As part of this project, Orano built a 2-cell (each cell is constituted of one producer well located in the center and surrounded by six injection wells in an hexagonal pattern) and a processing pilot plant that will be used to demonstrate the operability and economic viability of an ISR process. Another main objective of this pilot trial is to demonstrate the ability of Orano’s modeling tools to predict the ore behavior under given leaching conditions. To model uranium production by ISR, Orano uses HYTEC, a reactive transport computational software, which was adapted for its existing operation in Kazakhstan (Katco) to predict uranium recovery and reagent usage based on operating conditions. In order to perform similar simulations for this new deposit, Orano engaged in a comprehensive program including ore sampling, detailed characterization, and metallurgical testwork. The mineralogical conclusions were used to prepare a simplified geochemistry for the ore, in particular carbonate and reactive clay grades, uranium mineralization and penalizing elements such as pyrite. Then, bottle roll leach tests were used to characterize dissolution kinetics for smectite clays. Eventually, column leach test results such as pH, free acid, and uranium recovery were modeled on HYTEC to improve the fit of some of the dissolution kinetic parameters. Parameters fitted using metallurgical test work results will now be used as inputs for predictive model at the pilot scale, in order to anticipate operational results and help with operating decisions for production ramp up.

Jan 1, 2020

By Wen-long Zhan, Chun-en Zhu, Xiao-dong Du, Yong Zhao, Keng Wu

In view of the traditional evaluation index of sintering basic character- istics ignoring process information, several high temperature characteristic num- bers, which contain process information, were used to evaluate the sintering basic characteristics more comprehensively in this paper. The evaluation model of iron ore properties was established based on the high temperature characteristic numbers with employing fuzzy mathematics. Then, with the constraint of sinter properties and the raw materials, the ore blending model was built, whose target was to obtain the lowest cost and the best sinter properties. A multi-objective fuzzy linear pro- gramming was used to solve the model in order to get the best ore matching schemes. The ore blending model was then applied to the practical production, which was proved to be dependable.

Mar 1, 2018

By P. E. Cavanagh

"The Davis tube test has been used for many years as a laboratory method for determining the magnetic iron re-coverable from a magnetite iron orebody. This paper de-scribes a method for determining the recoverable iron from ores of the Labrador Trough type, with the usua1 flow sheet utilizing spirals followed by magnetic separation.The mechanical structure of a metamorphosed iron ore, resulting from recrystallization over long periods of time, is the basis for the laboratory method developed. Similarities between the structures of such recrystallized ores and the structure of annealed and recrystallized steel are noted.A laboratory technique to determine the size of the different grains of gangue and iron ore minerals is de-scribed and the application of this information to arrive at recommended grinding techniques and flow sheets is demonstrated. The use of the method to determine recoverable iron in such ores is compared to actual iron recovery in the pilot-plant and commercial concentrations of the same ore.The use of a specified lower limit of recoverable iron as determined by this method, in order to design open-pit limits, achieves practical results when compared to designing a pit based on an arbitrary lower limit of total soluble iron. The Ungava Iron Ore deposits are used in giving an example of the resulting pit design changes."

Jan 1, 1968