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By E Niva

The IsaMillÖ is challenging the way that plants are designed and operated. This paper challenges existing designs of concentrator flow sheets, particularly focusing on magnetite circuits.   From what has started out as a small scale ultra fine grinding mill in the pharmaceutical and pigment industries, it has been redesigned and improved upon for mineral processing, and has been the mainstay of fine grinding applications for over ten years. These applications have required energy efficient grinding to succeed, and have been predominately in the base metals industry.   Further development of the IsaMillÖ has now resulted in the machines being able to treat larger tonnages, with higher capacity motors. This development, along with the introduction of purpose designed ceramic media, has allowed the mill to treat courser feed sizes. At the same time, the mill still offers highly efficient grinding, and has enabled it to be operated in coarser tertiary and secondary grinding applications.   The acceptance of the mill in coarser applications, predominately in base metals and PGM applications, has enabled the IsaMillÖ to be a serious contender for beneficiation in other minerals. One such application is the potential for IsaMillsÖ to be part of magnetite flow sheets, which are being considered in Australia to meet the growing iron demand of China. The high energy efficiency of the IsaMillÖ compared to conventional technologies, as well as the smaller infrastructure requirements, provides a great opportunity to reduce the power intensity of magnetite circuits.   This paper will examine the use of IsaMillÖ technology in conventional grinding applications, including recent testwork in a primary grinding base metal circuit, as well as testwork on magnetite ore comparing a lab scale IsaMillÖ with a lab scale Tower Mill.   The growing demand for minerals over the next decade, coupled with higher energy cost, will result in energy efficient technology, such as the IsaMillÖ, being included in standard circuit design.

Jan 1, 2008

By S Reid, W Chen, T J. Donohue, A Katterfeld

The use of discrete element modelling (DEM) is widespread in the materials handling field, and is used for many applications. One of the important limitations in using DEM is the number of particles that can be modelled, with this limitation often resulting in increasing the minimum particle size in the simulation. This restriction on minimum particle size is usually accommodated in the calibration process where the parameters in the simulation are chosen in such a way as to reflect the presence of smaller sized particles, and in typical applications such as transfer chutes this is standard practice. However, in the application of vibrating screens the inclusion of the ‘fines’ is critically important due to their influence on the screening efficiency. In reality, the presence of fines reduces the screening efficiency for a number of reasons; however, the main mechanism that will be addressed in this study is the effect of adhering fines. This is where the fines adhere to the larger particles and are carried over into the lump stream. The approach for this study will be to firstly consider the relatively simple mechanical sieving process used in the determination of particle size distribution, and then this will be expanded to consider the application of vibrating screens.CITATION:Donohue, T J, Chen, W, Katterfeld, A and Reid, S, 2017. Addressing the challenges associated with the modelling of iron ore in vibrating screens, in Proceedings Iron Ore 2017, pp 155–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

ALTHOUGH it has been a matter of about one hundred years since the idea of the internal-combustion engine entered the mind of the inventor, the practical application of its use was not attained till 1860, when Lenoir produced an engine similar to the ordinary highpressure steam engine, with the valves arranged to admit the explosive mixture and the discharge of the exhaust gases. In this case no attempt was made to compress the gas before ignition, as it was then considered that the explosion under these conditions had a detrimental effect, inasmuch as it would act as a sudden blow to the working parts. Indeed, he went so far as to inject steam and water sprays to reduce the explosion.Under these conditions the consumption of gas was exceedingly high-about 106 cub. ft. of coal gas per b.h.p. per hour but the mechanical effect showed that the engine ran in every respect as smoothly and quietly as in best steam-engine practice.The extravagant consumption of this engine was clearly pointed out at the time by Gustav Schmidt in a paper before the German Society of Engineers, wherein he states :-" The results would be far more favourable if compression pumps, worked from the engine, compressed the cold air and cold gas to three atmospheres before entrance into the cylinder. By this means a greater expansion and transformation of heat is possible."

Jan 1, 1912

Power Plant. The power for the metallurgical operations is supplied by the company's own power plant, which is centrally situated. Power is also supplied to Metal Manufactures Ltd. and Australian Fertilizers Ltd., both being adjacently situated to this company'sworks.The power supplied is direct current, 250 volts, and is obtained from direct-current generators coupled to turbines and to Belliss & Morcom triple expansion engines.The steam supply is obtained from Babcock & Wilcox water tubular boilers, the fuel used being drawn from the South Coast coal mines.Transport. - The works are connected by standard broad gauge railway to both the jetties and the Government railway. Two steam and three electric locomotives are employed in this service.In addition to its own requirements, transport is provided to Metal Manufactures Ltd. and Australian Fertilizers Ltd.The various operating departments are connected by a 2-ft. gauge railway operated by Jeffrey electric locomotives.Ore Storage and Sample Mill - These departments are connected by broad gauge line to the Government railway and jetties. All material which is railed or shipped to the works from the various centres is weighed, sampled and placed in the ore store, or outside gantries, before being treated.Since the whole of the material received is either purchased or treated on a toll charge, great care is necessary in the weighing and sampling of all the receipts.Assay Oflice--The assay office is divided into several laboratories, where analyses of the various purchased materials and works samples are carried out.

Jan 1, 1938

By Ruy L. Rodrigues

Vale is in the early stages of commissioning its Onça Puma nickel operations. The project is meant for the production of 58,000 tpa of nickel contained in ferro-nickel, substantially contributing to the company?s vision to achieve world leadership in the nickel business. Mineral resources will be exploited from the homonymous deposits in the Midwest of state of Para, Brazil ? some 100 km southwestwards from the company?s Carajás iron ore properties. Resources as of 83 Mt at 1.73 % Ni will sustain a mine life of approximately 40 years. The property was acquired in late 2005 and Vale has since extended the engineering studies and proceeded with the implementation. Nickel will be mined from saprolitic ore at a rate of approximately 10 Mtpa (ore plus waste) in early years ? ramping up to some 15 Mtpa 7 years later ?, to feed the plant at a rate of 2.5 Mtpa. The process uses conventional RKEF (Rotary Kiln Electric Furnace) pyrometalurgical route whereby the ore is homogenized, calcined in rotary kilns, melted in electric furnaces and further refined to ferro-nickel. The plant has been designed and constructed applying the latest available technology, aligned with Vale?s vison to exceed the highest existing standards for environmental control, health and safety and productivity in the industry. Total investments in these operations are anticipated to correspond to USD 2.3 Bi and will materially contribute to the regional development and well being of the nearby communities and other stakeholders.

May 1, 2010

By H. B. Pulsifer

ONE of the most common basic open-hearth furnace products is a simple carbon steel with a carbon range from 0.05 to 0.15 per cent. The material is widely used for sheets, tubes, bars, wire and the innumerable special objects of secondary fabrication. The properties of the material vary over wide ranges, depending on the more exact composition and details of manufacture or treatment that affect its structure. The present paper is a review of those properties and structures that have been found by studying this steel as used in the cap screw industry. At first glance this might be thought a narrow application of the steel, but, since the industry uses the material in the cold-worked, annealed and heat-treated conditions, the title of the paper may be excused for its comprehensiveness. Yet, in studying the wide ranges of properties and structures that preclude a more specific title, there can be no suggestion of completeness or finality. Even a summary of a few years' work is no more than a preliminary survey of a field that will be fertile in scientific data and industrial products for many years to come. An outline of the structures will be given first, then a list of the previous contributions that are at hand and finally some details of the work and related problems, especially concerning this low-carbon steel in the surface-hardened condition.

Jan 1, 1931

By D. C. Oliver

Paper written on project work carried out in partial fulfilment of B.Sc. (Eng.) (Metallurgy and Materials) degree Corrosion in exhaust systems can occur on both the interior and exterior surfaces. Chloride-containing de-icing salts on the roads in colder countries greatly increases the rate of corrosion on the exterior surfaces. This paper investigates the relative exterior corrosion resistance of three alloys?two ferritic stainless steels( AISI Types 409 and 441) and an aluminized mild steel. The exhaust system is split into two categories?the hot end and the cold end. A test for each of these ends was designed?the standard ASTM G85test was modified to create a simulated driving cycle. The cold end test samples were exposed to ten driving cycles, and the hot end test samples were exposed to five driving cycles. A driving cycle constitutes the car being started from cold, driven until the operating temperatures are reached, and switched off and allowed to cool. Pitting corrosion is the primary corrosion mechanism occurring at the cold end of the exhaust system. The aluminized mild steel was the most resistant alloy in this test, and Type 409 the least. However, once the protective aluminium layer degrades, corrosion will occur rapidly. At the hot end of the exhaust system, spalling of the surface oxide layer is the primary corrosion mechanism occurring. Type 441 was the most resistant in this test, and the aluminized mild steel the least resistant. Potentiodynamic tests were performed on the alloys?the results agreed with the results obtained in the exposure tests.

Jan 1, 2003

By J. Betzhold

Knowing more about an orebody makes it easier to exploit it profitably. Many orebodies are made up of different rock types, alteration zones or mineralogical ensembles: oxides versus sulphides or facies with different metallurgical properties for example. Being able to model the spatial layout of these different facies is vital to good mine planning and management. Kriging cannot be used to generate numerical models of orebodies with complex geometric patterns because it gives too smooth an image. Over-smoothing has the meaning of changing the natural selectivity. Conditional simulations are required to do this kind of model respecting the natural variability: honouring the natural selectivity, dilution and ore loss. Standard geostatistical simulations cannot duplicate many of the complex spatial relationships seen in the earth sciences, such as differently orientated facies, sets of conjugate veins or ore types where certain facies cannot touch. After a presentation of the case study, it will be shown why traditional methods for simulating indicators like the sequential indicator simulations, or the truncated gaussian method, cannot be used to simulate it. Plurigaussian simulations are then introduced and shown to be more powerful than the previous methods in their range of application. This is confirmed by the case study treated; a Chilean copper deposit, for which the plurigaussian simulations are seen to respect the different orientations of the individual facies as well as honouring the facies seen in drill holes, and respecting the proportion of each facies even if this varies in space (e.g. increases or decreases with depth). Key words: geostatistics, indicators, conditional simulation, plurigaussian method, copper variability.

Jan 1, 2000

By H. C. Miller

The success of any project in which gas is injected into oil-producing sands to increase the current rate or the economic ultimate production of oil or in which surplus gas from oil producing operations is stored temporarily in reservoir sands that have been wholly or partly depleted of their producible oil depends mainly upon an understanding of the underground movements of oil, water, and injected gas and the ability to control their speed and direction of migration through the reservoir sands. Many operators believe that injected gas always travels up the structure and drives oil to wells structurally higher than the injection wells, because the specific gravity of the injected gas is less than that of the fluid substances in the formation. Consequently, many injection wells are located on the flanks of oil-bearing structures with the idea of utilizing the energy of the injected gas to drive the oil to producing wells higher on the structure. It is true, under certain conditions of pressure and fluid depletion of the reservoir sands, that injected gas will move in an up-structure direction, but the theory that injected gas always moves up the structure is based on an erroneous conception of the laws that pertain to the expansion of gases. By definition, "a gas is distinguished by its property of infinite expansion and is limited in volume only by the walls of the vessel which contains it."3 The expansion of gas that is injected into reservoir sands also is limited by "walls" that surround the space influenced by the injected gas. The walls of the majority of undrilled or virgin oil-bearing reservoirs in California are the impervious shales overlying and underlying the productive strata and the "dams" or effective barriers of edge water around the rims of the reservoirs. When gas is injected into the sands of a producing reservoir, regardless of the location of the injection well on the structure or the degree of depletion of oil from the sands, one of the walls which confine the gas in the structure about the injection well is fluid. This wall will be edge water in a nearly depleted reservoir, where the drainage cones or regions of reduced pressure about injection and producing wells intersect; and, where there is no interference of drainage cones and the injection well is structurally above the edge water, the wall will be oil. In some producing reservoirs bottom water may be the lower wall of the space that confines the gas about injection wells, but the effect of bottom water on limiting the expansion of gas is the same as if the water was not present and impervious formation separated the producing from the underlying nonproducing strata. Therefore, since compressed gas always seeks regions of reduced pressure and its final volume is limited only by formation and fluid barriers and since the force exerted by the gas under pressure is equal in all directions, the course of migration of injected gas in reservoir sands in California and the

Jan 1, 1932

By G. C. Price

This study traces the development of the bucket-wheel excavator, points out the differences in the German- and American-type wheels, and gives the major design criteria and the advantages and disadvantages of bucket-wheel operations. A computer program, written in FORTRAN IV for use with an IBM 360 computer, simulates the operation of the digging components of a bucket-wheel excavator. By supplying certain mining dimensions, soil characteristics, and machine design specifications, this program will print out a time study of the various components of an operation, power calculations for the operation, and production data. This program, when combined with a truck, belt, or rail program, should be helpful in planning a complete mining system In material suitable for a bucket-wheel excavator operation.

Jan 1, 1973

By James C. Barker

In 1981 and 1985-1986, the Bureau of Mines conducted orientation studies of marine placer platinum-group metals (PGM). PGM are derived from the Goodnews Bay ultramafic complex and magnetic surveys show that the complex extends offshore at least four mi. The present seafloor was an emergent foreland as recently as 8000 years ago. High-energy ocean processes are transporting and depositing sediment such that PGM-bearing materials are reworked and later masked by barren littoral drift. Exploration targets include 1) placers formed since present transgression began, and 2) ancient marine and drowned fluvial deposits. Additionally, there is evidence of PGM solution transport and accretion. At least minor values of PGM in Recent lag-type placers and possible submarine strands are concentrated along an offshore scarp incised through glacial deposits into the preglacial surface between Flat Cape and Red Mountain. Other Recent PGM-bearing features include Flat Cape shoal, Chagvan Bay, Salmon River delta, and modern beaches. Ancient placers include possible N-S fluvial systems 2 to 3 mi offshore, a nearshore scarp 50 ft below sea level, and strands adjacent to projected ultramafic bedrock slopes. The existance of ancient placers is dependent on depth of glacial erosion. SEM studies show PGM are principally isoferroplatinum and osmiridium, with minor sperrylite, moncheite, and platiniridium. Gold is a co-product, and concentrates comprise chromite, ilmenite, and magnetite. Beneficiation tests successfully concentrated precious metals from natural blacksand accumulations, but failed to concentrate low-grade lag gravels.

Jan 1, 2011

By Jennifer Riefenberg

A family of personal computer programs that calculate the Coal Mine Roof Rating (CMRR) has been developed by the U.S. Bureau of Mines. The CMRR rock mass classification system provides a link between the qualitative geologists' description of coal mine roof and the quantitive mine engineers' needs for mine design roof support selection, and hazard detection. The program CMRR is a user-friendly, interactive program into which raw field data are input. A CMRR is calculated and output along with two graphic displays. The first graphic display is a plan view trap with the CMRR's displayed on a color-coded scale. The second display shows a stratigraphic section of the bolted roof interval and its resultant CMRR. In addition, a Lotus 1-2-3 worksheet, computer file BOM-CMRR.WK3, has been developed for easy storage of field data. The worksheet includes four macros that automatically calculate CMRR's, store field test data in a database format, and print a two-page report of the field data and CMRR parameters. Production of summary port; for analysis of site-specific information are readily generated using Lotus 1-2-3 software. These programs help to facilitate the engineer in utilizing the CMRR in ground control studies.

Jan 1, 1994

By Lloyd B. Underwood

In the event of a sudden nuclear attack upon the United States, it is imperative that vital command and control centers have a high probability of survival. One such vital facility is the North American Air Defense Command Combat Operations Center at Colorado Springs, Colorado. Known briefly as NOW, this installation when completed will be housed in large chambers excavated out of granite beneath the eastern slope of Cheyenne Mountain (Figure 1). The NORAD COC, a U. S. Air Force sponsored project, will serve as the primary collection and evaluation center for data concerning unknown aircraft, missiles, or space vehicles, which might bring destruction to North America. The data will be fed into high-speed computers and electronic equipment from outpost sources - radar, ballistic missile early warning stations and picket ships throughout the world. Electronically controlled display boards will make it possible to evaluate the tracking data instantaneously and to take appropriate defensive action1.

Jan 1, 1965

By M. E. Volin

The Smuggler is one of the mines in the Aspen district, located the central part of Pitkin County, Colo. It was first examined in July 1943 by C. R. Wilfloy, former mining engineer of the Bureau of Mines at Salt Lake City, Utah, in, company with the lessees, R. D. Rohlfing of Aspen and J. W. Vanderwilt of Denver. The purpose of this examination was to sample a mineralized breccia zone that appeared continuous along the contact between the Leadville and Weber formations. These preliminary samples showed that the zone contains low but significant amounts of lead and zinc and that the minerals are partly oxidized and thus not easily concentrated. The mine was examined again in May 1946 by the senior author and William Herron, one of the present lessees of the property. This examination reviewed the previous sampling and recommended investigations by the Bureau of Mines. Sampling and drilling investigations were conducted by the Bureau from October 1946 to February 1947 and again from August 1947 to April 1948. Aspen is the center of a famous mining district that produced over $102,000,000 in silver and lead ores from 1880 to 1918, when a dispute closed down the mines (fig. 1). All of the workings below the Cowenhoven tunnel in Smuggler Mountain and the lower Durant tunnel in Aspen Mountain have been flooded since that time. The Cowenhoven portal now is caved, and Smuggler Nos. 1 and 2 tunnels are the only accessible workings in Smuggler Mountain. The only operating mine is the Midnight, situated 4 miles south of town at an altitude of 9,700 feet.

Jan 1, 1950

By O. C. Blade

Diesel fuel is being used in greater volume than ever before in the United States. During 1950 railroads used 43 percent of the total volume of Diesel fuel sold, smelters, mines, and manufacturing plants used about 13 percent, highway vehicles such as trucks and busses, and equipment such as tractors and bulldozers accounted for approximately 20 percent, about 12 percent was used by water craft, and the remaining 12 percent by gas and electric utilities, the military forces, and oil companies. These figures were calculated from data issued by the Bureau of Mines. 2/ Comparable figures for 1951 and for 1952 to date are not available, but recent information indicates that well over 11,000,000 barrels of Diesel fuel per month are produced by the country's refineries. 3/ More information on this increasingly important type of engine fuel is needed by the petroleum industry, engine manufacturers, and consumers, particularly on the grades and qualities of the Diesel fuels being marketed. To supply this information the American Petroleum Institute and the Bureau of Mines, United States Department of the Interior, under cooperative agreement, are conducting annual surveys of Diesel fuel oil produced in refineries in this country.

Jan 1, 1952

By K. M. Connor, O&apos

Variations in overburden geology must be considered in applying subsidence prediction methodologies developed by the U.S. Bureau of Mines (USBM). To characterize rock mass overlying high-extraction coal mines, the USBM utilizes a computer spreadsheet program and modified Rock Mass Rating (RMR) system. The spreadsheet calculates an RMR based on a bed's engineering properties determined from core logs and laboratory tests. An in situ deformation modulus and a bending stiffness are computed for each bed. Stiffness-versus-depth plots identify groups of beds with similar stiffness. Large variations in stiffness between adjacent beds are considered significant horizontal discontinuities where slip is likely. Time domain reflectometry (TDR) is used to verify this hypothesis by measuring shear displacement along such discontinuities. A model of the overburden is built by assuming that a near-surface laminated beam exists above a transition zone in which large plastic slip occurs along horizontal discontinuities. Increasingly thicker groups of beds are modeled to determine the most probable beam thickness based on a comparison with measured deflection profiles. The inverse of maximum beam deflection is an index parameter known as "bridging potential," a single value that incorporates both overburden geology and mine geometry.

Jan 1, 2010

By D. W. Dareing

Multiple branch wellbores and horizontal holes, when applied to deep lying ore bodies, have the potential of significantly reducing well costs by reducing total footage drilled per acre of well pattern. In addition, horizontal holes may increase sweep efficiency. Well completion is a major problem. They must be cased to contain leaching solutions within the underground portion of the production loop. Several drilling and completion concepts are given and evaluated in the report. Our evaluation shows that there is economic incentive to further develop these concepts for field application to ore bodies 1,500 feet. Multiple branch concepts are the most attractive. They can reduce well costs by as much as 30° when applied to 2,000 feet ore body depths (44%, at 5,000 feet) and can accommodate a lamer pump than conventional vertical wells. We recommend this concept be developed further to accommodate either dual or triple branches.

Jan 1, 1980

By E. D. Gardner

This paper is a progress report on the study of mining methods and costs in the western United States and summarizes that part of the work pertaining to the undercut block-caving method of mining. Ore is mined on a large scale exclusively by the undercut block-caving method at the following six mines in the western United States: The Morenci branch of the Phelps Dodge Corporation, Morenci, Ariz.; the Ray mines of the Nevada Consolidated Copper Co. at Ray, Ariz.; the Inspiration Consolidated Copper Co. at Inspiration, Ariz.; the Miamo Copper Co. at Miami, Ariz.; the Ruth mine of the Nevada Consolidated Copper Co. at Ruth, Nev.; and the Consolidated Coppermines Corporation at Kimberly, Nev. The undercut block-caving method is also used at the mine of the Andes Copper Mining Co. at Potrerillos, Chile.

Jan 1, 1930

By Kenneth M. Maas

The Bureau of Mines inventoried the land in southwestern Alaska to classify ownership and availability and compared this land with known mineral terranes and mineral deposits. This report discusses and quantifies the potential for favorable location of mining claims for metalliferous (locatable) mineral deposits. Of the nearly 24 million acres that constitute the study area, approximately 3.6 million acres or 17% are available for mineral location, 3.4 million acres or 14% are available with restrictions, and 17 million acres or 71% are unavailable. Mineral terranes are known to underlie about 7.8 million acres or 33% of the study area; 3 million acres or 38% occur on land available for mineral location, 1.3 million acres or 17% occur on land available with restrictions, and 3.5 million acres or 45% occur on unavailable land. The State of Alaska has opened over 91 % of its land in the study area to mineral location; in comparison, the Federal Government allows mineral location on 0.07% of the land under its jurisdiction. There are 117 known mineral deposits or occurrences within the study area, including 77 lode deposits and 40 placer deposits. Of the 41 lode deposits occurring within a mineral terrane, 2 occur on available land.

Jan 1, 1988

By R. H. Storch, D. C. Holt

During reconnaissance investigations of more than 300 stream areas in Idaho to determine the potential value of ilmenite in black - sand placer deposits 46 deposits were explored by churn drilling , trenching , test pitting , or shafting . The component mineral content and total black - sand content were determined for more than 8,690 reconnaissance and exploration samples . Data compiled during the investigation indicate a good potential for large , low- grade deposits containing ilmenite , monazite , columbite , euxenite , uranothorite , and other radioactive black minerals and accessory black - sand minerals . The data also indicate most deposits will be economic only if several component minerals can be recovered as coproducts .

Jan 1, 1963