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By L. A. Price

With increased stripping ratios and with dwindling ore content, the mining fraternity is increasingly turning to larger and larger equipment for profitable open pit operations. The availability of higher horsepower prime movers and increased-capacity electric transmissions using either wheel-mounted or axle-mounted traction motors makes a reality of single-axle, rear dump trucks having 150 to 250 ton capacity. The size of electric loading shovels is inherently geared to the size of haulage equipment. To work effectively with this new generation of trucks, the Harnischfeger Corporation has introduced its P&H Model 2800 with a capacity of 20 to 25 cu yd and a working weight of nearly 1,500,000 lb. The Model 2800, depicted in Figure 1 loading a 200 ton truck, has many new electric and mechanical features designed to give excellent production and low cost operation. Chief among the new features is the ELECTROTORQUE control system. Electrotorque is a completely static, solid state electronic system supplying controlled power both to the armatures and to the fields of the d-c shovel drive motors. It eliminates many major electrical rotating machines and their attendant maintenance. The system was developed jointly by ASEA of Sweden and Harnischfeger Corp.

Jan 1, 1970

By J. S. Hansen

In support of its objective to conserve mineral resources by minimizing premature failure of materials, the Bureau of Mines conducted a cooperative study with the U.S. Department of Energy on the erosion and abrasion resistance of hard materials for valves in coal conversion systems. This report describes a newly developed erosion-testing apparatus and presents data on the erosion resistance of over 200 materials. Erosion resistance of most metals was comparatively low. In contrast, ceramics and cermets such as B4C, WC, SiC, Si3N4, and TiB2, when fabricated to minimize porosity, displayed greater than five times the erosion resistance of metals. Coatings such as boron diffused into Mo and WC, chemical-vapor-deposited TiCN, and electrodeposited TiB2 were highly erosion resistant if applied in thicknesses ranging from 60 to 75 µm. Erosion resistance of cemented carbides was inversely related to metal binder content.

Jan 1, 1979

By John Paul Gries

This Bureau of Mines study outlines the history of 11 major metal ore deposits or districts that are relatively new discoveries. The oldest operation is the White Pine mine, where major exploration was initiated in 1929. Discovery (delineation of ore bodies) dates range from 1948 to 1976. All but two of the deposits, Quartz Hill in Alaska and Flambeau in Wisconsin, are or shortly will be in major production.

Jan 1, 1979

Objective To reduce dust generated from soiled floors within enclosed operator cabs. Background Enclosed operator cabs are widely used on mobile excavation equipment in the mining and construction industries. They protect the operator from bad weather, noise, and airborne dusts. The inside cab environment usually must be kept at very low dust concentrations because of quartz dust generated from the excavation of silica-bearing rock. For cabs to be effective in controlling airborne respirable dust, they must have an efficient air filtration system, while providing a positive pressurization of the cab interior. Ideally, the recirculated and exterior makeup air filtration should provide at least 99% capture efficiency for dust particles as small as 0.3-µmaerodynamic diameters. Many of these enclosed cabs use heating units mounted or directed along the floor (see figure 1), which can cause dust entrainment problems. Prior studies by the National Institute for Occupational Safety and Health (NIOSH) of enclosed cabs have shown that these floor heaters can generate notable amounts of dust within the cab enclosure (see Technology News 486). Multiple-shift dust levels measured inside a drill cab increased on average from0.04 mg/m3 during the summer months to 0.68 mg/m3 during the winter months. Additional dust level measurements, made with optical particle counters during a nondrilling time period, verified that dust levels inside the cab increased from 0.03 to 0.26 mg/m3when the floor heater/fan was turned on. Dust levels within the cab also became greater than the ambient air dust levels outside of the cab when the floor heater was turned on during the nondrilling time period. This shows that the floor heater was a notable dust source problem. Cab floors are commonly soiled from operators tracking dirt inside the cab upon entering from the mine or construction site. Interior cab dust levels can be increased by (1) airflow disturbance of the soiled floor or (2) operator disturbance of the soiled floor. Approach During prior NIOSH surveys of surface coal mine drills, several drills with very low cab dust levels (#0.1 mg/m3) were observed to have floor sweeping compound spread out over the cab floor during the working shift. This initial observation led to a more controlled A-B study of the effect of the sweeping compound on the interior cab dust levels. This study involved dust sampling with and without sweeping compound inside the cabs of a bulldozer and two drills. Sweeping compounds commonly use sawdust or cellulose as the main bulk material, with oil or wax added for dust adhesion purposes. Sand is sometimes added to increase bulk density. Sweeping compounds with sand are commonly used to sweep up concrete floors. Those without sand (usually referred to as "gritless") are used to sweep up smooth finished floors. Most of the oils and waxes used for the adhesive ingredient are petroleum-base and can have an irritating odor. People sensitized to petroleum distillates could have allergic reactions to these sweeping compounds. A few companies offer non petroleum-base sweeping compounds, using either a natural oil or chemical additive for dust adhesion. During this study, it was decided that only the gritless sweeping compound (without sand) would be used, eliminating the addition of another potential silica source inside the cab. Since the sweeping compound would be applied on the enclosed cab floor for the duration of the shift, it was decided to use a canola oil-base sweeping compound to eliminate irritating odor from the petroleum-base sweeping compounds. The natural canola oil-base sweeping compound had a slight woody scent. The three pieces of equipment used in this study had notably different cab layouts. The bulldozer had a small cab with vents discharging air-conditioned or heated air from adjustable louvers at operator waist level and floor level. The bulldozer also had a cloth fabric seat and a carpeted floor. Drill A had a large cab with the heat directed from adjustable louvers at operator knee level and the air-conditioned air directed from cabin ceiling louvers. This drill had a vinyl fabric seat and a steel plate floor. Drill B had a small cabin with the heat directed across the floor (see figure 1) and the air-conditioned air directed down from the ceiling. It had a vinyl fabric seat and a worn rubber mat on a steel floor.

May 1, 2001

In the January Bulletin a list was published of Societies' publications, magazines, etc., which were duplicates and were discarded at the time of-the consolidation of the libraries of the three Founder Societies. A second list published herewith includes text books which are duplicates and which will be disposed of about April 1, 1916, by the Board of Directors of the Institute through the, Library Committee.. If, meanwhile, members desire to secure some of these books, they are asked to communicate at once with the Secretary as. this is an unusual opportunity to secure books at an extremely low price. Airy, George Biddell.-Magnetism, London, 1870, Bd. Alberti, Friedrich von.-Halurgische geologic. Erster Band. Zweiter Band. Stuttgart, 1852, Bd. American Iron and Steel Association.-Ann. Rep. of the Sec'y. Statistics of American and, Foreign Iron Trades, 1877. Phila., 1877, Bd. Same, for year 1878. Phila., 1879, Bd. American. Telephone and Telegraph Co.-Ann. Rep. of Directors to Stockholders, 1911. N. Y., 1912, paper. Armagnat, H.-Induction Coils. Trans. by Otis Allen Kenyon, N. Y., 1908, Bd. Armstrong Cork Co. Insulation Dept. Nonpareil Corkboard Insulation. Pittsburgh, 1909, Bd. Associazione fra gli Industriali Metallurgici Italian.-The Metallurgic industry of Italy. Description of some of the principal works. Milan, 1911, Bd.

Jan 2, 1916

By C. Wade, A. Swart, M. Dworzanowski

AngloGold Ashanti operate a pyrite flotation plant at their East Gold Plant, Acid Plant and Flotation Plant (EGAF) metallurgical complex within their Vaal River operations in the North West province in South Africa. The flotation plant feed is reclaimed pyrite rich tailings and the concentrate produced is used as the source of sulphur for the EGAF acid plant. The sulphuric acid produced is in turn used for the recovery of uranium at the Vaal River South uranium plant. The original flotation plant built in 1960 was based on the use of many small volume flotation cells and was becoming very expensive to operate and its age severely limited further operation. A decision was taken in 2005 to replace this plant with a new one based on fewer, larger volume flotation cells. This paper describes the benefits of using larger volume flotation cells in this new flotation plant when compared to the smaller volume flotation cells in the old plant. The benefits of the new plant include a smaller plant footprint, fewer flotation cells, fewer pumps, no distribution boxes, simpler piping, a greater flotation volume and a reduction in installed power. The saving in capital cost could not be quantified because of the age of the old plant. The savings in operating cost will arise from fewer operators, less maintenance and reduced power consumption. The new plant has not been in operation long enough to quantify the benefits in operating cost and metallurgical performance. However, recovery improvements can be expected given the greater flotation volume (increased residence time) and the installation of larger, more efficient flotation cells.

Jan 1, 2007

By Matthias Rheinlander

The paper will describe Virtual Design and Construction (VDC) as a tool which will enable us to build a project ?virtually? on a computer before constructing and operating it in the real world. VDC computer models are built, using information from various sources including survey, 3D laser scanning, CAD and GIS to represent the project and its components in a coordinated and consolidated infrastructure model. This model is reviewed and evaluated by, and shared among project teams including owners, con-tractors, designers, engineers, construction managers, stakeholders and operators. It allows teams to fix costly design and construction issues before construction on site. Benefits and lessons learned from global projects will be discussed

Combined Flow Sheet for Treatment and Recycling of Municipal Solid Waste (MSW) with Complex Morphological Composition

Sep 13, 2010

The results of a series of physical model studies of the stability of jointed rock slopes carried out some years ago are described. These models were tested under centrifugal loading. Four ?geological? structures were tested; all had the same joint orientations and strengths, but the relative spacing of the joints was different. The results showed that the mechanisms of failure of the slopes varied for the different models, and the gravitational loads at which failure developed also varied. The following conclusions are drawn from the results of the physical model tests: ?the mechanism of slope failure is by progressive deformations throughout the slope ?the ratio of the spacings between the different sets of discontinuities exerts considerable influence on the slope failure ?in the models tested, the intact material strength had no noticeable influence on the stability of the jointed rock slopes(note that for hard rock, similitude conditions indicate a prototype slope height of 300 to 400 m, and therefore intact rock failure might not be expected under simple gravity conditions, i.e. no tectonic stresses) ?rock slope failures are three-dimensional and in general are not amenable to two-dimensional simplification ?knowledge of the orientations of discontinuities in the slopes does not allow prediction of a unique failure surface, nor of a volume of failure. The volume of failure is determined to a large extent by the plan configuration of the slope.

Jan 1, 2006

By Herbert H. Einstein

Swelling ground is one of the most feared problem in tunneling. Although usually not causing sudden failures during construction, the very large and long- lasting deformations give contractors and designers the impression of facing an inevitable phenomenon against which there is no technical defense. Examples are concrete liners of up to 1 m that have been cracked or crushed, tunnel inverts that are heaving at a rate of 0.1 m per week during construction and continue to heave during decades. This author (Einstein (1979). Einstein et al. (1972) (1975)) and others (Huller (19761, Grob (1972) (1976). Golta (1967), tienke (19761, Krause (1976). Lee et al. (1976)) have described many cases of swelling tunnels that illustrate the significance and magnitude of the problem. This paper intends to show that tunnels in swelling rock can be built to perform satisfactorily. . For this purpose the tunnel builder needs to know how to determine the existence and specific behavior of swelling ground, how to select appropriate structural characteristics of the tunnel and predict its performance under the specific ground conditions, and finally how to construct the tunnel such that the anticipated performance will be achieved. This concept of a design-construction procedure is the same as that for tunneling in general; it is mentioned here for NO reasons: 1. To point out that design and construction cannot and should not be separated. The way in which the tunnel will be built has to be an integral part of the design. 2. This paper will be structured corresponding to the procedural concept.

Jan 1, 1981

By W. J. Errington

The Isasmelt process was developed at Mount Isa Mines Limited in Queensland, Australia in collaboration with CSIRO, the Australian Government research organisation. Originally developed for primary lead smelting, culminating in the construction of a 60,000 tonnes per annum lead smelter at Mount Isa, this technology now also provides a major part of the current 200,000 tonnes per annum copper smelting capacity at Mount Isa. A programme is now in place to expand copper production to 250,000 tonnes per annum. The technology has also been applied to secondary lead smelting at Britannia Refined Metals, a MIM subsidiary company, where a 30,000 tonnes per annum lead plant based on battery scrap feed has been operating since 1991. Mount Isa Mines Limited decided to license the technology in1988, and copper smelting plants utilising Isasmelt technology are now operated by Cyprus Miami Mining Corporation in the USA and by Sterlite Industries in India. In addition, the technology was adopted by AGIP for smelting copper/nickel concentrates in Australia. Union Miniere are currently constructing an Isasmelt furnace to smelt and convert copper-containing materials at their plant at Hoboken in Belgium. This paper discusses these developments and also some likely future developments which include the application of the technology for continuous copper and nickel converting and applications in the treatment of zinc-containing residues.

Jan 1, 1997

By Ram Avtar

High tensile thick plates (>80mm, weight ~3000 Kg) of medium carbon low alloy steel, when heat treated, manifested higher percentage of crystalline area (>20%) in fractured surface. Such problem was not encountered in thinner plates. The genesis of higher crystallinity in fracture was examined. It was observed that the thicker plate undergone slower rate (Average 0.9oC/Sec.) from soaking temperature to Ms temperature) of cooling after austenising during oil quenching and thereby quenched microstructure had upper bainites. During tempering of as quenched bainite, additional precipitation took place at the lath boundaries of bainite. This led to weakening of grain boundaries and aided easy crack propagation during fracture and resulted in formation of higher percentage of crystalline area in fractured surface. Enhancement in cooling rate (Average 1.8oC/Sec. from soaking temperature to Ms temperature) of austenised plate by switching over from oil quenching to water quenching practice resulted in complete transformation of austenite into martensite and produced ductile fracture (zero Crystallinity). Plates conformed improvement in mechanical properties between 2-5%.

Jan 1, 2009

By Carol E. Jones

Outline ? Reclamation is a primary mitigation. ? Understand baseline environment and land use. ? Determine reclamation goals. ? Selecting reclamation technology. ? Determine technical risk. Reclamation ? Primary Mitigation ? Through land and water disturbance, mining can have significant local and regional environmental impacts. ? Impacts can also result from associated land use changes. ? Reclamation is a primary tool that the mining industry uses to manage its environmental impacts.

May 1, 2008

By M. Misra

The processing strategy for the effective separation of bitumen from low grade (< 10 weight percent bitumen) Utah tar sands by a hot water process differs significantly from that used for the processing of high grade (> 10 weight percent bitumen) Utah tar sands. Excellent separations (coefficient of separation = 0.9) can be achieved for high grade Utah tar sands by intense hot water digestion followed by a modified froth flotation step. Such a technique is ineffective for low grade tar sands. In order to change the characteristics of the low grade tar sand an attempt was made to enrich the bitumen content of the feed to greater than 10 weight percent by recycle of bitumen concentrate to the digestion stage. However the quality of the separation was not improved under these circumstances. Similarly feed enrichment by heat treating the low grade feed with recycled concentrate prior to digestion did not improve the separation. More successful separations of low grade Utah tar sands were finally achieved by modification of the viscosity of the low grade bitumen with controlled addition of diluent. These results of the hot water separation tests and variations in the quality of separation are interpreted in terms of the physical properties of the bitumen and the surface bonding forces operative at the bitumen-sand interface.

Jan 1, 1979

By M. Somerville, S. Sun

The liquidus temperature and viscosity of a range of melter slags produced in South Africa were determined. Drop-quench experiments were carried out on the supplied plant samples to determine the liquidus temperature and phase relations at sub-liquidus temperatures. The temperature measurement range covered 1300°C to 1630°C. Results from these experiments show liquidus temperatures for the melter slags to be in excess of 1500ºC with the chromium containing spinel as the primary crystalline phase. At lower temperatures, an olivine or pyroxene phase co-existed with the spinel phase. The viscosity of the slags was determined over a temperature range of 1350 to 1550°C, under a controlled atmosphere. Results show two orders of magnitude variation in the viscosity (0.2 to 20Pa s) with strong effects of slag chemistry and temperature. Slags with lower SiO2and Cr2O3concentrations were more fluid. Slags with the lowest FeOx and highest SiO2concentrations were the most viscous. These observations are in accord with general behaviour of silicate slags. While the presence of a spinel phase may have an effect on the viscosity of the melter slags, results obtained to date indicate a much stronger effect due to the presence of an olivine or pyroxene phase at lower temperatures. Keywords: phase equilibria, liquidus, viscosity, slags, olivine, spinel, pyroxene

Jan 1, 2004

By James T. Bartis

Review of Key Issues Affecting the Prospects of CTL in the United States ?Issues of concern to the public - Impacts of coal mining - Water use - Greenhouse gas emissions ?Issues of concern to investors - CTL production costs - Oil prices - How greenhouse gas emissions will be managed ?RAND recommendations

Jan 1, 2009

By Peter Fischer

Between 45,000 and 50,000 claims for subsidence are submitted each year to the German hard coal industry. In order to improve the service to claimants a quality management was established in 2005. This paper describes the process now used for handling these claims. A quality check has also been carried out by way of a customer survey, which was performed by an independent research agency. The results of the survey are presented in this paper. In Germany, research into mining subsidence mainly involves the prediction of ground movements caused by deep mining operations. Special areas of research are subsidence reducing aspects of the extraction panel planning, especially from the point of view of mining dynamics, as well as securing and restoration measures. This work seeks to prevent or minimize mining-induced damages close to the surface, for instance, buildings or infrastructure installations (such as pipelines), or underground mine openings (e.g. shafts). Roof collapses and surface fractures caused by shallow mine workings of an earlier era currently constitute a special area of investigation.

Jan 1, 2006

By J. J. Bezuidenhout

The waste-heat boiler is used within the Sulphide flash smelting process as the main dust and energy recovery unit. The large volume of off-gas discharged from the flash smelter is at a very high temperature (1350°C) and contains a significant dust load that subjects the downstream waste-heat boiler to tough and demanding conditions. The boiler cavity is especially prone to dust accretions, fouling, and corrosion caused by accumulation of molten particles and precipitation of sulphuric acid. Computational fluid dynamics (CFD) is applied within a qualitative study to model the flow and heat transfer distribution throughout the waste-heat boiler. The commercial CFD package, Fluent 6.2.16, was applied to a modified waste-heat boiler (23 m ×11 m ×5.4 m) within the Outokumpu flash smelting process. This investigation focuses on the geometric modifications to the typical boiler design, which includes elevation of the ceiling, placement of flow-obstructing baffles and radiation plates parallel within the flow path. Also investigated were various boiler operating conditions such as the circulation of process off-gas, air leakage from the dust discharging hoppers and variation in inlet gas composition. The geometric modifications had the desired effect of increasing the volumetric utilization and therefore enhancing heat transfer between the boiler surface and the gas stream and dust segregation. Introducing circulated off-gas at a rate of 20 m/s and at a 45° angle to the front of the waste boiler further enhanced cooling while reducing the high impact of the furnace-uptake gas-stream on the boiler ceiling. The placement of radiation plates was found to be very effective in enhancing the heat transfer surface and distributing gas flow within the boiler. These results present recommendations towards an improved waste-heat boiler design. Keywords: flash smelting, waste-heat boiler, CFD simulation, off-gas cooling.

Jan 1, 2008

By K. G. Stowe

"1. Introduction Mattagami Lake Mines and Orchan Mines operate zinc copper mines adjacent to one another near Matagami, Quebec, situated approximately 300 kilometres north-east of Rouyn-Noranda. (Note: Mattagami Lake and Orchan are in the process of being absorbed by Noranda Mines and will become Noranda Mines-Matagami Division). Both concentrators began operations in late 1963.The Mattagami Lake concentrator is capable of treating up to 3,500 metric tons per day of massive sulphide ore with a mineral composition shown in TABLE 1. The Orchan concentrator consists of two separate circuits - the Orchan circuit with a capacity of 1,050 metric tons per day and a custom circuit with a capacity of 825 metric tons per day. Throughout its operation, Orchan has custom milled ore from several smaller deposits in the Matagami district."

Jan 1, 1979

By P Lotz

With the recent increase in environmental awareness, gold mining companies are fast becoming signatories of the International Cyanide Management Code (ICMI, 2007). The objective of the Code is to improve the management of cyanide used in gold mining and to assist in the protection of human health and the reduction of environmental impacts associated with the use of cyanide. In particular the code specifies the following cyanide concentration limits: 50 ppm WAD cyanide in a tailings storage facility, 0.5 ppm WAD cyanide for effluents, and 0.022 ppm free cyanide or 0.022 ppm WAD cyanide as surrogate in the post mixing zone of river discharge. Weak acid dissociable (WAD) cyanide refers to those cyanide species liberated at a moderate pH of 4.5, such as HCN(aq) and CN-, and the majority of Zn, Cd, Cu, Ni and Ag complexes with low dissociation constants. It is potentially toxic to humans and animals. Gold plants using cyanide should ideally measure WAD cyanide online and destroy WAD cyanide in excess of the applicable limits to ensure compliance with the Code. Mintek has recently developed an online WAD cyanide analyser (WAD Cynoprobe). The WAD cyanide analysis technique is based on the use of a ligand exchange reagent that liberates WAD cyanide bound to metals such as Zn, Cd, Cu, Ni and Ag. The ligand exchange reaction is represented by the following chemical equation: Metal(CN)X + yLigand &#8596; Metal(Ligand)y + xCN- The plant filtrate is treated with a ligand exchange reagent, to liberate WAD cyanide, before measuring the free cyanide concentration via amperometry. The WAD Cynoprobe measures both free and WAD cyanide concentration. Its fast analysis time, approximately five minutes, makes it suitable for use in the control and optimisation of the cyanide destruction and recovery process. The instrument has proven accurate and reliable in the analysis of synthetic copper, nickel and zinc cyanide solutions made up in the laboratory as well as under industrial gold plant conditions during various trials. The WAD Cynoprobe has gained widespread commercial acceptance and is currently implemented on nine gold plants around the world.

Jan 1, 2007