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During the latter part of 1937 consideration was given to the construction of a; local smelting plant for producing blister copper. Previously copper concentrates had been shipped to the United States of America. The proposition had the advantages of a saving in cost of realization, quicker financial return and reduced dependence on overseas shipping.The smelter was designed by the existing staff, who had difficulty in obtaining data on small plants, particularly on the reverberatory furnace. Construction was started in March, 1938, and the reverberatory was blown in on January 16th, 1939. One roaster had been operating for several weeks prior to this date.While results and operating technique on this new departure in small-scale smelting are barely beyond the experimental stage, it is felt that the experience gained to this time should be recorded to help fill the obvious gap in published information covering plants of this type.At present there are three copper smelters operating in Australia; the other two plants are equipped with blast furnaces.LOCATIONThe new smelter is situated in a position convenient to the concentrator and to the power plant. The site is traversed on two sides by a brick flue, from an old smelter plant, which connects with a 250-ft. stack. This stack and portion of the old flue are used in connection with the...

Jan 1, 1939

By Dziurzyn&apos, W. ski

This article outlines the results of a computer simulation reproducing the transport of a mixture of air and methane following the outburst on 25 November, 2005 in transport gallery D-6, bed 409/4, at the ?Zofiówka? hard coal mine. Based on a mathematical model, numerical method and boundary conditions from the disturbance caused by the outburst, the Ventgraph system of computer simulation programs was adopted for the study. We performed a computer simulation of the influence exerted by the outburst on the propagation of the air and methane mixture, and compared the results of this simulation with those of the actual event as registered by sensors of the mine monitoring system. A validation of the model allowed us to present temporal changes in the concentration of methane and air along flow routes. Keywords: mine ventilation, outburst of methane, numerical simulation, monitoring system.

Jan 1, 2008

By Guan Jichang

An abandened breakwater, located at the rear of No. 2 berth in Dongdu Port area of Xiamen City, was not cleaned thoroughly when the backfilling of sand started. The uncleaned stone layer was about 2 to 3 meters deep, with the average piece of stone weighing about 1 to 3 kN. A large grain storing house, 220X 60m2 in area, was designed and built at the above mentioned complicated site. The foundation of the grain house are made up of the cast-in-situ piles. It is well known that it is difficult for the submarine engineering drill to go down through such large-sized stones. Having com-pared the various plans, a final decision has been made which involves explosions with small amounts of charge plus cone bit in the enlarging of the size of the pores. Such a method has successfully prevented the pores from slumping and made it possible to fulfill the project without any difficulties. This paper also introduces the ways in effectively dealing with each individual stone.

Jan 1, 1991

Generating short- and long-term mine production schedules in isolation and independently from each other means that only a local optimum can be achieved when each scheduling phase is carried out. The globally optimal solution however, can be achieved when integrating scheduling phases and accounting for the interaction between short-term and long-term activities simultaneously. This paper addresses the task of integrating short- and long-term production plans by combining the short-term objective of minimising deviation to targeted mill feed grade with the long-term objective of maximising net present value (NPV) into a single mathematical model. A case study is presented which compares the present values of the same stope data set scheduled via separate long and short-term models and than by the proposed integrated model which applies a predetermined penalty for each tonne of metal deviation to target for the respective ore tonnage being processed. This allows an operation to obtain a globally optimal scheduling regime when taking into consideration the cost and loss of value resulting from fluctuations in grade to the mill over the short-term.

Dec 6, 2010

By Kathryn C. Sole

A novel solvent-extraction process for the refining of gold was recently commercialised, with the commissioning in May 1997 of a 24 t a-' refinery at Harmony Gold Mine in Virginia, South Africa. The MinataurTM Process (Mintek Alternative Technology for Au Refining) uses solvent-extraction technology to produce gold of 99.99% purity from the cathode sludge arising from a conventional carbon-in-pulp / electrowinning circuit. Implementation of this process introduces significant cost benefits compared with the conventional dore smelting / toll-refining route previously followed. This paper outlines the process, presents selected operating results obtained during the first few months of operation, and provides some details of the associated techno-economic advantages.

Jan 1, 1998

By C. E. Rork

This paper discusses various mechanical improvements that have been gradually incorporated in the copper-willing plants of the Southwest daring the past 14 years, power plants for concentrators, use of large-size units of equipment, and the effect of plant capacities on costs. The improvements in mechanical equipment and plant design have contributed in the reduction of operating costs; in some instances a saving in the capital cost per ton of daily capacity milled has resulted.

Jan 1, 1935

By E. R. Maize

[In %-port of Invcstiptionn 7452 ,g dcniing with roof ~wet,ent in the Cmcibla r~ine, rof&apos;erence .,as m.da to the f~ct tiwt timker decny war, bsing studied at tho tine of writing. Thic napor, written a3er completion of that ~tudy, describ~s t1l.e ~mrl&apos;: and sunlharizea the fiats obtained. Ifhen tlle stu* oi roof novement bras be,- at Cxcible tw igeas \%.ere a6-r;incsd. on decay of tiriber Q: scne of :he olficialr;: (I.) 9:la.t timber decay v:as unustmlly rapid in ,tho Ciuoiblc mins, ,m?. ((2) that timber coated with rock ri..~st deixiyad morrl mpirlly thnn those %hat vsrc not so coated. Thsx ::ore no records by which tkeso &apos;iaeas could &apos;L;e tertcc?, ard it cnpsarefi vise to make a limite6 in- vo3tiption, p~.rticu!.ai.ly of +.he effect of roc!< dusting on decny, as rock ductirg is nn importnnt mer-ns of ~rc-,rcnt?;~g cad-dust eql-osions. ]

Jan 1, 1941

By Max J. Spendlove

The secondary copper industry is comprised of numerous enterprises which collectively employ many of the recovery and refining processes now used in primary plants as well as many other processes that are unique to the industry. Effective methods are used for identifying and segregating all types of scrap according to widely accepted standard classifications. Segregated scrap and waste materials usually require some preliminary processing to remove both valuable and deleterious associated constituents. Smelting, melting, alloying, and pyrorefining are common methods used for producing secondary metal, but operating techniques usually differ from primary metal operations because of the difference in physical and chemical properties of the respective raw materials. Some copper scrap is converted to copper chemicals rather than to refined metals or alloys. Recovery efficiencies of all processes are reasonably high, and the quality of products meets rigid specifications.

Jan 1, 1961

By I. Tsolas

This paper presents the use of non-parametric approach (i.e., data envelopment analysis, DEA) for the development of environmental sustainability indicators in mineral processing using environmental, economic and/or integrated indicators (i.e., indicators that interrelate two dimensions of sustainability). A case study based on real publicly available data is presented to illustrate how the proposed approach can be implemented in practice. The merit of this approach, which is based on the productive efficiency framework, is that it provides environmental sustainability indicators that can be used internally for benchmarking purposes and externally for sustainability reporting.

Jan 1, 2008

By Alan H. Goode

Glass wool meeting requirements for commercial use was made from glassy fractions of urban solid wastes by the Bureau of Mines. This research was a part of the Bureau&apos;s program to develop building products and other usable materials from reclaimed urban waste materials. Mixes of molten glass were fiberized into glass wool during laboratory studies by impingement of a jet of compressed air on a stream of the molten glass. The principal test variable studied was composition of the melt; this was varied by adding dolomite and alumina to obtain molten glass with the handling characteristics required for producing final wool products of the desired composition and physical characteristics. When no charge is made for the waste glass and approximately $75 per ton can be obtained for the wool product, an interest rate of return on investment after taxes of about 12 percent can be obtained. If a charge of $5 per ton is required for the waste glass, a selling price of about $78 per ton would be necessary to obtain a l2-percent-interest rate of return on investment after taxes.

Jan 1, 1972

By J L. Mauk

&nbsp;Broken Hills is an adularia-sericite epithermal Au-Ag deposit, hosted in flow-banded rhyolites and overlying rhyolitic pyroclastic rocks in the eastern Hauraki Goldfield. The 7.1 Ma deposit was the largest producer of gold in the eastern Hauraki Goldfield, and was one of very few economic deposits hosted in Pliocene rhyolites. This paper presents the results of a recent study in the upper levels of the deposit. Maps and cross-sections constrain structural and lithological relationships, and the lateral and vertical extent of a breccia pipe û the major feature of the upper levels. &nbsp; Previous studies in the upper levels of Broken Hills have shown that gold and silver values are concentrated around and within a large breccia pipe, mined by a series of æcaveÆ stopes and in veins. Contour diagrams of Au-Ag data from channel samples indicate that the breccia pipe was a major fluid channel-way for mineralising solutions. &nbsp; The breccia pipe deposits are part of the dynamic geothermal system that formed the Broken Hills ore bodies; they developed as a result of hydrothermal brecciation in areas of structural weakness within a rhyolite pyroclastic unit that overlies a massive rhyolite lava-flow unit. The main breccia pipe begins near the rhyolite/pyroclastic contact, having the shape of an inverted, inclined cone, and consists of silicified breccia, stringers of quartz, and irregular patches of clay-altered country rock. Smaller zones or pockets of hydrothermal eruption breccia are silicified and contain low grade gold in the matrix and in the adjacent silicified wall rocks. &nbsp; Quartz has been classified according to its physical characteristics as seen in situ and hand specimens indicate that vein definition decreases upwards, perhaps as a result of changing lithological conditions and/or increasing proximity to the paleosurface. Hydrothermal quartz is widespread as veins and as a replacement mineral, or lining fractures and cavities and overgrowing rock fragments. Breccias contain vein quartz, but some quartz veins cross-cut breccias, indicating that vein and breccia formation was relatively synchronous and overlapped in time. &nbsp; Disseminated gold-silver mineralisation is associated with vein quartz and silicic alteration of the wall rock within the breccia pipe. The auriferous zones are highly irregular and erratic, and sampling results show a wide range of gold-silver ratios, suggesting that highly volatile physiochemical conditions prevailed during mineralisation.

Jan 1, 2005

By Darrell Wilder

When designing excavation support systems in urban environments, it is often necessary to consider the effect of vertical surcharge loads from adjacent structures. Several methods are used in practice to establish the horizontal surcharge-induce pressure on the excavation support. According to the experience of the authors, these methods often seem to overestimate the effect of the surcharge and may have significant impact on the construction costs. This paper explores several of these procedures and provides a discussion as to the reasons for the differences in surcharge effect predictions between different procedures. It also provides practical recommendations for designers dealing with excavation support design.

Jan 1, 2006

By James A. Brierley

Wastewater from uranium mines in the Ambrosia Lake district near. Grants, New Mexico, U.S.A., contains uranium, selenium, radium, and molybdenum. The Kerr-McGee Corporation has a novel treatment process for waters from two mines, sections 35 and 36, to reduce the concentrations of the trace contaminants. Particulates are settled by ponding, and the waters are passed through an ion exchange resin to remove uranium; barium chloride is added to precipitate sulfate and radium from the mine waters. The mine waters are subsequently passed through three consecutive algae ponds prior to discharge. Water, sediment and biological samples were collected over a 4-year period and analyzed to assess the role of biological agents in removal of inorganic trace contaminants from the mine waters.

Jan 1, 1981

By D. D. Munro

Finsch Mine is a kimberlite diamond mine located at Lime Acres in the Northern Cape Province of South Africa. The mine was founded in 1961 and started surface mining in 1964. Underground production commenced in 1990 using a modified blast-hole open stoping method for the mining of Blocks 1, 2 and 3. Block 4 is currently being mined as a block cave. The process of identifying and optimizing a method to mine the Block 5 orebody started in 1991, and in 2006 incline caving was identified as being technically feasible. This paper aims to document the process employed in developing this method by the Block 5 prefeasibility team as well as discuss the technical challenges encountered during this process. The paper commences with a history of Finsch Mine and highlights the complex geology and threat of sidewall failure that prompted the decision to use block caving as the mining method for Block 4. A literature study of mines that implemented mining methods upon which the incline cave was conceptualized is then presented. These practices were then used to form the basis for the designs on which the initial geotechnical modelling was done and built upon through an iterative process of modelling and design changes. The ventilation of the mining area, initial productivity simulation results, and the applicability of automation and comminution processes in the incline cave are also presented. The paper concludes with an investigation into some of the challenges of the mining method, and shows that that incline caving is a technical option available for further investigation in determining the optimal mining method to be employed at Block 5, Finsch Diamond Mine. Keywords massive mining, incline caving, geotechnical modelling.

Jul 1, 2013

By A. C. Johnson

This circular is one of a series published by the Bureau of Mines describing mining and beneficiation methods and costs at various mining operations throughout the United States. Inclusion of the Abbott mine in this series is of particular interest, as the complex geology and the character of the deposits make their exploitation a unique operation. The mine operates on a high-cost, comparatively small-scale basis, and only the persistence of an aggressive management has enabled it to maintain its rank among the major mercury producers of California. Rising costs and decreasing metal prices, which continuously threaten the low profit margin, are reflected in increased efficiency of operation. This report summarizes past operations and describes, in detail, the geology and ore deposits; exploration and mining methods; and furnacing and condensing operations. It covers the entire operation from initial exploration to the actual production of mercury. Comparative production costs for 1944 and 1958 are of special interest.

Jan 1, 1962

By A. Koski

A pond rehabilitation and environmental education project were proposed by Cleveland-Cliffs Michigan Operations (CCMO) and approved by the Michigan Department of Environmental Quality (MDEQ) and the United States Environmental Protection Agency (USEPA) as partial fulfillment of conditions for a stream mitigation permit. The goals of the project were the rehabilitation of a pond on a tributary of a local trout stream, enhancement of public access and appreciation, and the initiation of a site-based environmental educational curriculum. Cleveland-Cliffs undertook a suite of actions to rehabilitate a pond created by a previous mining operation in 1912 and make accessible to local schools the aquatic and riparian ecosystems. Cleveland-Cliffs partnered with the local governmental unit and two local school districts. The rehabilitated pond and riparian zone provide an accessible natural area that local residents can use for such activities as hiking, biking, walking, fishing and nature study. Vegetative enhancement includes the planting of native shrubs, wildflowers and showy herbaceous plants in the pond, on the riparian fringe and the surrounding area. An interpretive trail was developed around the pond with signs created by a local master watercolor artist. Local schools built and installed picnic tables, benches and a kiosk. Cleveland-Cliffs created pond lesson plans tied to the Michigan Curriculum Framework, developed inexpensive teaching kits and hosted a workshop for teachers from nine local schools. Classes regularly utilize the pond during the school year conducting environmental studies. Nesting boxes, wildflower gardens, bat houses, frog deformity surveys and water quality studies are a few of the activities that classes have conducted at the pond.

Jan 1, 2007

By Stanton L. Tainter

As a part of a wartime program to aid in the development of known ore bodies and in the discovery of hitherto unknown deposits of strategic minerals, the Bureau of Mines investigated the feasibility of diamond-drilling the Christmas copper deposit, in Gila County, Ariz., to increase the reserves of milling ore. Upon recommendation of the examining engineer, drilling was begun in September 1942, from the bottom (770) level of the mine. One month later, in cooperation with the Bureau, the Federal Geological Survey started geologic mapping of the mine workings. Since extensive and costly development would be required, the War Production Board concluded that ore below the bottom level could not be mined at that time because of the wartime shortages of equipment and man-power. In January 1943, drilling was moved to the 300 and 400 levels to locate reserves readily accessible for continued production of fluxing ore. This drilling, which was under the supervision of L. G. Marshall, was completed in January 1944.

Jan 1, 1948

By Mark Ioli, Debra Struhsacker

In September 2004, Gale Norton, U.S. Secretary of the Interior, presented the Manhattan Mine with a U.S. Bureau of Land Management’s 2004 Hardrock Mineral Environmental Award. The Manhattan Mine is a sustainable development showcase. The reclamation accomplishments at this Nevada gold mine demonstrate how modern reclamation techniques can restore an old mining district into an aesthetically pleasing landscape that can support multiple and sustainable uses. In a collaborative effort that relied on substantial community involvement, Round Mountain Gold Corp.(RMGC) has improved the environment and eliminated a number of public hazards associated with old, unsafe mining features. RMGC’s community collaboration, innovative engineering, creative reclamation design and corporate commitment to environmental excellence show what Secretary Norton’s 4 Cs Initiative looks like on the ground and inaction.

Jan 1, 2005

A geologic, petrographic and geochemical study has been performed on the pyroclastic flow deposits in the coastal area of East Zhejiang Province, Southeast China. This study leads to classification of the pyroclastic flow deposits into three associations: the extrusive type, the surge type and the ash flow type welded tuff associations. Through detailed investigation and comparison of the characteristics of these lithologic associations, with emphasis on the welded tuffs, a comprehensive model has been proposed to demonstrate the petrogenesis of the pyroclastic flow deposits.

Jan 1, 1995

By Daryl R. Tweeton

This Bureau of Mines publication ill scribes present practices of making injection wells for in situ uranium leaching. Casings, screens, drilling fluids, coring, logging, cementing, and developing are discussed with the objective of aiding those who are starting an in situ leaching operation. Improper choices of materials or techniques can result in wells that are either useless or wells that have an undesirably high resistance to injection. Important factors include careful selection of screen slot size, use of logs for choosing the cementing basket depth, proper cementing techniques, and careful choice, use, and flushing of drilling fluids. The information was obtained through observation of well construction and through discussion with in situ leaching companies, drillers, and suppliers.

Jan 1, 1978