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By K. Delbeke

Within the framework of the EU Existing Substance (93/793/EEC) and REACH regulations EC/1907/2006), the copper industry initiated in 2000 a comprehensive Voluntary Risk Assessment of copper and several copper compounds. The Italian Government's Istituto Superiore di Sanità, reviewed the process and reports on behalf of the European Commission. Copper exposure levels to man and the environment from production of copper anodes and cathodes, copper powders and copper chemicals as well as fabrication and use of semi-fabrication products and down stream user products were collected across Europe. Environmental and human health effects data were obtained from literature as well as novel research programs and used to deduct safe threshold

Jan 1, 2007

By J. T. Hanks

Process development is one of the principal tasks required in the course of turning an exploration discovery into a mine. Exploration geologists should have an understanding of the more important metallurgical processes and the test work required for each process. The paper discusses the important metallurgical processes, the test work and sample requirements for each, and the costs and time requirements to accomplish the testing. The limitations of reverse circulation drill samples for metallurgical testing are discussed. The level of process definition required to support engineering studies: scoping, pre-feasibility and feasibility studies are also described.

Jan 1, 1997

By P. C. Good

High-purity chromium was prepared in massive form by the electrolysis of chromium trioxide solution at high temperatures. The metal thus obtained, containing 50 to 150 p.p.m. of oxygen, 20 p.p.m. of nitrogen, and traces of metallic impurities, could be hot-worked to rod and sheet and drawn to wire ductile at room temperatures. Optimum concentrations and operating conditions were established for the deposition of chromium from chromic acid baths containing sulfate, fluoride, and silicofluoride ions. Current efficiencies of 13 percent were attained with baths containing sulfate ion, and efficiencies of 40 to 44 percent with baths containing fluoride and silicofluoride ions. Cation exchange resins were used for removing metallic impurities from chromic acid solutions containing sulfate ion; solutions containing fluoride and silicofluoride ions were purified by recrystallization.

Jan 1, 1960

By Justin R. Patts, Andrew B. Cecala, A. KYLE LOUK, Emily J. Haas

The National Institute for Occupational Safety and Health (NIOSH) and the former U.S. Bureau ofMines (USBM) have given a significant effort over the past four decades in researching and developing engineering controls and interventions to reduce mine workers’ dust exposures during the bagging and palletizing of industrial minerals. Workers performing manual bagging and palletizing of 50- to 100-pound bags typically have some of the highest dust exposures of all workers at mining and mineral processing operations. This paper will provide an overview of available dust control technologies for bagging operations and present the findings of a recent case study that was conducted at four different industrial sand operations to identify the current types of bagging and palletizing technologies being used and to evaluate their effectiveness in reducing workers’ exposures to respirable crystalline silica dust. An evaluation will also be performed to determine if further reductions in respirable dust levels can be achieved by incorporating additional modifications or improvements into the existing technology.

Apr 3, 2020

A viable flow sheet of the sorption-flotation technology for gold recovery from low-grade ores and concentrates using powdered activated carbon modified by organic compounds as the sorbent-bearer has been developed. The powdered activated carbon, with high kinetic ability and sufficient specific area, was selected as the all-purpose gold cyanide complex-bearing sorbent which is active during flotation. To improve carbon adsorption capacity and to provide the required floatability its porous structure was filled with a quaternary ammonium compound which can extract gold cyanide complexes and render additional flotation properties to the carbon. To optimise the process and to simplify the layout, adsorption and flotation processes were carried out simultaneously in a mechanical flotation cell. The proposed technology was used for extended and pilot-plant tests of sorption-flotation gold recovery from 0.6 g/t Au final tailings and 2.0 g/t Au gravity tailings. The extended tests were carried out on Taseevskaya (Chita Region) flotation tailings, whereas pilot-plant tests were conducted on Kommunarovskaya (Krasnoyarsk Region) gravity tailings passing to cyanidation, followed by processing with filtration technology. Additional gold recovery from Taseevskaya final flotation tailings was 50.8 per cent. Gold recovery from Kommunarovskaya final gravity tailings was 92.5 per cent. Compared to the complete sludge process conventionally used at the plant, gold recovery was increased by 7.5 per cent due to lower gold losses in the liquid phase and conversion of the refractory non-cyanided metal into a carbon concentrate. This paper presents the experimental results of gold adsorption onto powdered activated carbon modified with quaternary ammonium compounds (sorbent-bearer) as well as sorbent-bearer flotation with various collectors from cyanide solutions and pulps.

Jan 1, 2005

By O. M. Arafat, J. A. Finch

Since its development, the functional performance equation for ball milling (McIvor, 1988) has facilitated a new understanding of industrial circuit cause and effect relationships, leading to significant strides in operational performance. Success stories of this approach to plant circuit performance improvement are now too numerous to list. Finch and McIvor (circa 1986) also discovered that the functional performance mill grinding rate at the size of interest was the same cumulative grinding rate that is calculated from mill feed and discharge size distributions using a first-order rate equation. By calculating these cumulative grinding rates for all screen sizes, a complete ball mill model is generated (as used by Finch and Ramirez, 1981). Others in industry, Hinde and Kalala (2009), for example, have noted the same. Lacking the complexity needed to maintain their interest, most researchers have ignored this model, broadly opting instead for Epstein’s (1948) characterization of grinding as a chemical reaction, combining selection rate and breakage size distribution functions. The much simpler ball mill model has previously been incorporated into a proprietary circuit modeling program (McIvor, 2005) and used for plant improvement work (for example, see McIvor and Finch, 2007, and McIvor, 2014). Now, by combining this business-friendly ball mill model with optimization criteria from functional performance analysis, a circuit modeling system (including the needed supplementary steps to assure successful plant implementation of circuit design changes) is at the disposal of every plant metallurgist, grinding equipment/ material provider and circuit designer.

Jan 11, 2017

By Lewis V. Wade

This report provides background information concerning a mine roof simulator currently being considered by the Bureau of Mines. The simulator is a mechanical device with the ability to simulate the forces and displacements associated with mine roof over an area 20 by 20 feet. The topics covered in the report include a conceptual description of the system, definition of system capabilities, discussion of how such capabilities were decided upon, description of available control modes, and a comparison between the mine roof simulator facility and similar facilities existing elsewhere.

Jan 1, 1974

By M English, M Yumlu

At times of high metal prices, mining projects that have previously been put into the ætoo hard basketÆ are now being more closely examined. Typically these projects include the potential recovery of small mineable tonnes with high contained metal values and often with poor ground conditions. For many underground mining projects, the drift and fill method is viewed as a high-cost method and a æmethod of last resortÆ. As a result the method is not well known in Australia and it is the authorsÆ view that the method is under utilised. The drift and fill method can be applied to a variety of underground mining situations and is a preferred method for some orebody geometries and where ore recovery is viewed as a key to project success. This paper examines some of the critical mine planning and backfill issues involved with the drift and fill mining method.

Jan 1, 2008

By Matt Brandon

This case study demonstrates how integrating drone and GPS surveying with 3D modeling software creates more effective blast designs that address specific geotechnical challenges while improving safety and blast performance. In this case study an 80ft (25m) highwall experienced recurring slip plane failures exacerbated by a previously mined 40ft (12m) bench that removed back support, creating an unstable triangular rock mass. Previous blasting along this wall displaced the upper 40ft (12m) of material, opening geological discontinuities and causing progressive slope failures that compromised crew safety and blast effectiveness. High-resolution drone photogrammetry, GPS surveying, and laser measurements were employed to precisely map slip planes, bedding planes, and fault structures within the bench geometry. These geological features were imported into 3D design software to develop a shot pattern that strategically utilizes natural rock discontinuities rather than working against them. GPS-guided hole placement ensured accurate field implementation, while marking geological features on the surface of the bench provided visual references for the blast crew. The final blast design positioned the last row of holes to break preferentially along an existing slip plane while avoiding intersecting the next slip plane behind the blast. Explosive loading and timing sequences were adjusted based on the hole location relative to the 3D geological model to optimize fragmentation while maintaining wall stability. The optimized design improved highwall stability significantly, by reducing the slip plane failure mechanism that had previously compromised operations. Measurable improvements included enhanced highwall stability, reduced back-break, improved blast performance, and reduced safety risks for equipment operators and blast crews. Two subsequent shots using identical methodology were able to remove the rest of this problem area, confirming the repeatability and effectiveness of this integrated approach. This methodology demonstrates practical integration of surveying technologies with geological understanding to solve complex blasting challenges. Accurate 3D modeling of geological features enables blast designers to work with natural rock structures rather than against them, resulting in safer, more effective blasting practices. This case study shows the value of understanding the precise locations of geological features for optimizing blast design and provides a replicable process for addressing geotechnical challenges in blasting operations.

Jan 26, 2026

By R. Pelton, Z. Dai, S. Yang

ABSTRACT Hydrophobic polystyrene nanoparticles were evaluated as potential flotation collectors for pentlandite. The flotation of hydrophilic glass beads demonstrated the nanoparticles’ ability to induce flotation. Deposition of nanoparticles on glass surfaces increased the contact angle and enhanced adhesion of the beads to air bubbles. High flotation recoveries were achieved when 5–10% of the bead surfaces were covered with nanoparticles. Surface functionalization—the addition of vinylimidazole to polystyrene nanoparticle surfaces—caused the nanoparticles to selectively deposit onto pentlandite surfaces in the presence of Mg-Si slimes. Ongoing work includes attempts to identify specific applications where nanoparticle collectors might be cost effective. _ KEYWORDS Flotation, Nanoparticle collector, Coverage

Jan 1, 2014

By Jerry L. Smith

Industry on a whole has not been very receptive to government prodding to implement waste minimization programs. Waste minimization has the appearance of substantial benefits, however, there are underlying difficulties and suspicions that need to be addressed before industry will support pollution prevention initiatives. They can be summarized as follows: - Human behavior resists change, uncertainty, and unknowns. - New waste minimization techniques are difficult to find and research. - Calculating the true cost of present waste practices as well as new techniques being considered is difficult and time consuming. - Getting a consensus opinion of all the individuals affected on the course or technique to be employed in a pollution prevention program. New software products have addressed many of the problems associated with implementing pollution prevention programs: They contain research on a large number of pollution prevention techniques and case studies; they generally are accessed by EPA ID number, chemical name, or synonym; and some programs have the option to print a comprehensive written user-specific pollution prevention program.

Jan 1, 1994

By R. W. Raymond

(Cleveland Meeting, October, 1912.) UNDER the names of Conservation, Social Justice, the New Nationalism, and Progressive Democracy, many earnest reformers are calling for a new system of Federal government to replace the one which they ascribe to our fathers, and declare to have been outgrown. They are proposing the lease by the United States of certain natural resources on the public domain, for the profit of the U. S. Treasury, instead of the sale of such resources to private citizens or associations of citizens. In the present paper, I shall try to show that this notion is neither new nor good. It is clear that the United States is owner, as well as sovereign, of public lands acquired through conquest or purchase from other nations, as it was owner of the public lands expressly ceded to it by the original thirteen States. Its policy with regard to such lands involves, therefore, two entirely distinct questions: What shall it do as owner ? and, What shall it do as sovereign ? The latter question, it must be confessed, has played but a small part in our history. All the prerogatives of sovereignty which were not explicitly conferred upon the Federal government by the original States were retained by them. The ownership or control of precious or other metals or minerals in the earth, for instance, was thus reserved to the several sovereign States. New York, South Carolina, and other States have passed laws on this subject, without regard to Federal authority. As new States have been successively admitted to the Union, the tacitly accepted theory has been,. that they thereby acquired all the reserved rights of the original States. These newer States largely outnumber the first. thirteen; and it is inconceivable that they would submit to any deprivation of sovereignty based on historical grounds. One of them-Texas-came into the Union by its own voluntary

Oct 1, 1912

By Ronald J. Roman

A mathematical model was developed for the grinding and flotation section of Union Carbide's Bishop mill and this model was used to indicate how variations in grind, retention time, and calcite and fluorite content effects the mill capacity, tungsten units produced, and the grade and recovery of the scheelite concentrate. A model such as this is a starting point in determining the economic optimum running condition for a mining and milling operation and an example of this is given.

Jan 1, 1969

By Jonathan J. Dewsbury

It is argued that approximate computer based methods are only suited to modelling conventional piled rafts, for pile enhanced rafts where the interactions will be non linear three dimensional finite element analysis is required. However current 3D finite element analysis often relies on symmetry to reduce computational cost and there are concerns over the dependency of the results on the user. Therefore a new strategy within the finite element framework has been proposed. The main advantage of this strategy is that each stage of the model can be checked for consistency. There is also the added benefit that non symmetrical models can easily be constructed by tying the validated components together without dramatic increases in computational time. The proposed strategy compared well to the published results of a hypothetical example of a piled raft previously analysed with numerous methods by Poulos et al. (1997).

Jan 1, 2010

By William J. Campbell

These investigations were undertaken as part of a program to determine the optimum X-ray spectral lines to use for analyzing the wide variety of samples received by the X-ray Laboratory. Theoretical calculations and experimental data derived from these investigations show that longer wavelength spectral lines, > 2A, are very useful for many analytical problems. Because of the low fluorescence yield of the elements of atomic numbers 13-22 and the small depth of penetration of their X-ray spectral lines, these elements were originally considered to be insensitive; however, these studies show that the wide dispersion of their spectral lines, coupled with their weak beta lines, permits the use of wide collimation, thus increasing the line intensity. More importantly, the background due to scattered primary radiation is very low in the long-wavelength region.

Jan 1, 1959

The Northparkes E26 Mine is AustraliaÆs first block cave mine. This paper presents an outline of the design and construction philosophies that drove the project development and details the excavation, ground support and construction methods used. Features of the block caving method at Northparkes include:high production rates from multiple drawpoints;hard blocky ore fractured along gypsum veins; andloading/unloading of openings due to mining induced stresses.The drawpoints are subjected to high abrasion from the flow of ore, as well as impact from both secondary blasting and from the production LHDs. In order to withstand these harsh conditions and to ensure a low maintenance environment, a conservative approach to ground support was taken. The experiences gained during construction are discussed and whether the design expectations have been achieved. By installing a high level of ground support during excavation of the openings subject to mining stresses, a low maintenance environment has been constructed. Operating costs are therefore minimised and Northparkes E26 Mine continues to produce at the lowest cost per tonne of all Australian underground mines.

Jan 1, 1999

By F. C. Appleyard

As one of the more important Industrials Minerals, gypsum occupies a significant place in the economy of the United States, particularly in that segment which can be loosely called the Construction Industry. For many years, products made from gypsum have been a major building material, and the usefulness and versatility of these products is such that their widespread use is expected to continue. In 1968, according to U.S. Bureau of Mines statistics, the value of all gypsum products sold in the United States was 405,000,000 - and although this value has dipped from the 1964 high of $ 432,000,000, it is expected to trend upward in the next few years to equal and surpass this figure as the construction industry recovers from its current squeeze of "tight money" and high interest rates. There are many factors to be measured in determining the potential value of any mineral deposit, and how it might fit within its particular industry. What, then, are the qualities which a gypsum deposit must have in order to profitably participate in the four hundred million dollar plus business which is the gypsum industry? First let's consider the geology of gypsum, the geographic distribution of deposits, and the more important factors such as size, grade, capital requirements, and operating cost. Then, an understanding of the uses of gypsum, various types of products, and location of markets would be helpful, along with such other factors as the structure of the industry, price trends, etc.

Jan 1, 1970

By D Morrison, P Goodman

The cycle time between adjacent stopes is critical to achieving the required production rate from 3500 Orebody; one of the Enterprise Mine orebodies. Current Mt Isa cemented fills require a 90-day cure period which had to be cut to 30 days while maintaining the required strength criteria. The Enterprise Mine Feasibility Study recommended that this be achieved by Cemented Slurry Rock Fill (CSRF), but that on-going research into paste fill be continued. The continuation of the research, in conjunction with overseas visits has recommended that the 3500 Orebody be filled with paste fill, with the potential to fill other orebodies. The paste fill will comprise cyclone and thickener dewatered copper tailings to which Portland Cement (PC) is added before vertical borehole delivery and undergound pipeline reticulation to individual stopes. The benefit is not only re-use of copper tailings but also much reduced binder usage.

Jan 1, 1998

By C. D. Chapman

Current regulations regarding the landfill disposal of asbestos containing wastes are inadequate to ensure there are no ground water or airborne emissions. Accordingly, there is growing recognition that asbestos wastes can only be safely disposed of by using techniques that destroy the hazardous fibres. An innovative high-temperature plasma arc technology (The MAGRAM Process) is being developed for the recovery of magnesium metal from asbestos together with supplementary magnesia containing feedstock. The furnace will operate in. open bath mode with aluminium and/or ferrosilicon being employed as reductant. An important advantage of the process is that magnesium vapour within the furnace will be generated close to atmospheric pressure rather than at reduced pressure under which existing processes operate. Thermodynamic modelling work has been undertaken to define the range of slag composition and furnace temperature under which magnesium production at atmospheric pressure is feasible. The effect of slag chemistry, reductant addition, and temperature on product quality and yield have also been investigated and key aspects have been tested on bench scale. A 300 kW pilot plasma furnace unit has been employed for the treatment of calcined asbestos wastes. Aspects of design and operation of the unit are detailed. Acknowledgement: This work is substantially financially supported by the European Communities under the Industrial and Materials Technologies (Brite EuRam H) Research and Development programme.

Jan 1, 1995

By Strathmore R. B. Cooke

That calcium will activate quartz for flotation with anionic collectors such as soaps has been known for a number of years,1 2 3 and the method has been applied to the concentration of various iron ore 4 5 6 as well as to other materials. Clemmer gives the permissible pH range for the activation of quartz by calcium as between 9.5 and 12.5 with an optimum value of 11.0, and Hertzog7 has determined the calcium abstraction of iron ores and of Ottawa sand, but otherwise little quantitative data are available. The purpose of the present investigation was to determine those conditions under which dilute solutions of calcium chloride will activate quartz for anionic flotation and to determine the amount of calcium ion adsorbed by quartz. Those variables, the influence of which was primary, such as calcium, sodium, and hydrogen ion concentrations, were studied. Other factors which influenced the results are discussed in the description of the experiments. Three different experimental methods were used to determine the activation of the quartz. The first method was to treat a sample of ground, deslimed quartz with solutions of calcium chloride and sodium hydroxide, and to determine the calcium adsorbed by chemical analysis of the solution. Ad- vantages are that a direct value for the

Jan 1, 1949