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By G. L. Hundley

An anhydrous chlorination process has been developed by the Bureau of Mines for the production of copper, ferric oxide, and sulfur from chalcopyrite. The first part of the process is a chlorination step in which elemental sulfur and a mixture of iron-copper chlorides are produced. This paper describes the second step of the process in which the copper and iron chlorides are reacted with oxygen to selectively convert the iron chloride to ferric oxide and chlorine leaving the copper in the chloride form. The chlorides are pulverized and dropped countercurrent to a flow of oxygen in a vertical 20-cm-diam. reactor at 800° C. By leaching with brine, the copper chloride may be separated from the insoluble iron oxide and reduced to copper powder by electrowinning. It has been demonstrated that 70 to 80 pct of the iron can be converted to oxide in a single-stage operation with a chlorine content in the offgas of 80 pct. After removal of the oxygen, this chlorine could be recycled to the chlorination step. A two-stage operation will convert 98 to 99 pct of the iron in the mixture to insoluble oxides. The offgas from the second stage contains 70 pct chlorine.

Jan 1, 1974

By Boris J. Kochanowsky

In the mobile crushing unit system trucks are replaced by a conveyor resulting in a "continuous" almost "fully-automated" operation with all its attendant advantages. In consequence, overall operating costs are greatly reduced. Because of the new designs of large mobile crushing units that have been brought on-to the market, the use of these plants has increased significantly during the last three years. This paper describes the designs of new mobile crushing units, and emphasizes the advantages that such plants offer to the rock products and mining industries. It examines operating costs, and indicates the conditions in which the application of these plants is most profitable.

Jan 1, 1968

Bigger is indeed better in today's surface mining operations. That is especially true regarding haul trucks. Building larger, "supersize" trucks, however, means designing more powerful engines and drive systems that are also more efficient and environmentally friendly. And miners are demanding that these trucks have longer service lives with minimum maintenance. So truck makers are teaming with engine manufacturers and mining customers to design these larger trucks that will ultimately lead to reduced mining costs. About 180 of those truck makers, engine designers and miners gathered in Tucson, AZ in September to discuss the state of haul trucks in today's mining environment. Haulage 2000 was sponsored by World Mining Equipment and attracted attendees from around the world. Manufacturers described the latest in haul truck advancements. These included the design of more powerful engines, improvements to mechanical and ac and dc drive systems and suggestions on how to reduce maintenance spending. Technology improvements in tires for larger struck was discussed as was the cost efficiency of new, lighter-weight bed liners. The following is a summary of a handful of the presentations.

Jan 1, 1997

Coagulation-Neutralisation Technology to Treat Wastewater from Lead-Zinc Concentrator

Sep 13, 2010

G. D. Kneip, Jr., and J. 0. Betterton, Jr. (Union Carbide & Carbon Corp., Oak Ridge, Tenn.)—The authors have contributed to the theory of zone melting by considering the effects of the solidification of the final zone on the distribution curves for the finite length bar. However, they do not consider in sufficient detail the restrictions imposed by the particular metals involved. Eq. 4 has the analytical solution which is equivalent to Pfann's' equation for normal solidification of the final zone. For distribution coefficients less than one, it is apparent from this form of the equation that, as the solidification approaches completion, the concentration attains extremely large values which are inconsistent with the density of physical materials. The necessary restrictions then are that the solute concentration cannot exceed the density of the alloy, or more frequently, the solubility limit in the solid phase. Secondly, the distribution coefficient cannot be constant from 0 to 100 pet solute unless the liquidus and solidus coincide over this whole region. It would thus be more correct to impose limits on the solubility such as would be indicated by a typical eutectic diagram. Furthermore, in this case the assumption that the distribution coefficient remains constant is more likely to be realized. Eq. 4 should then be replaced by the following C,,(x) =k/L-x [ ?11 3 C11 (x)Ddx - ?11 4 Cn(x)dx= k[Cn (L-l)/k] [ L-x/l]x-1 L-l = x = L-l [kCenterlie/Cn (L-l)]1/k-1 The typical shape for the distribution curve in the final zone is indicated schematically in Fig. 12 for the simple eutectic case. The solidification proceeds according to Pfann's' expression until the concentration reaches the maximum solubility in the solid phasc. At this point, the concentration changes abruptly to the eutectic composition and remains at this value for the duration of the solidification. The width of the flat region, and the back reflection of this effect into the concentration curve on subsequent passes, depends upon the ratio of the eutectic concentration to the original concentration, upon the distribution coefficient, and upon the number of passes. Similar effects on the concentration curves in the first zone length would be expected in many systems for which the distribution coefficient is greater than one, and where the maximum solubility is not too much larger than the original concentration. The discussers agree with the authors that the assumption that the liquid is uniform in concentration should be considered with caution. Kneip and Better-ton' have shown, however, that in floating zone refining of zirconium, using induction heating, the distribution of iron agrees with theory which assumes a uniform liquid composition. Hence, in this case, the experimentally realized distribution coefficient agrees with the present phase diagram within the experimental uncertainty. L. Burris, Jr., C. H. Stockman, and I. G. Dillon (authors' reply)—The authors are happy to have received the comments of G. D. Kneip, Jr., and J. 0. Betterton, Jr., which provide additional insight into the zone refining process. It is true that the equations developed are inapplicable if the solute solubility in the solid phase is exceeded. However, this restriction on the use of the equations was clearly stated in the paper. A closer approach to

Jan 1, 1957

By Larry L. Snyder

A compact 4.87 m (16 ft) diameter tunnel boring machine (TBM) is capable of boring a 12.2 m (40 ft) radius curve while gripping horizontally, or vertically, as may be required for the excavation of turnouts. The machine's 5.0 m (16.5 ft) length and a patented machine structure allows steering while boring without causing harmful eccentric loads. An extremely stiff thrust system, rigid front and rear grippers, and the torsional stiffness of a front end electric cutterhead drive combine to create superior machine stability and boring efficiency. A 2.2 m (7.2 ft) diameter prototype, complete with a soft ground shield attachment, was used successfully on a tunnel project in Scotland.

Jan 1, 1989

By Raffaella Granata

The paper deals with the remediation of two areas formerly utilized for the disposal of hazardous wastes in a petrochemical plant. The works, designed on the basis of the criteria of maximum safety and minimum environmental impact, consisted in the confinement of the contaminated soil and groundwater within surface caps and perimetrical cut-off walls embedded in the underlying clay layer. The cut-off wall is 0.8 m thick and has a maximum depth of 33 m: it was designed to guarantee, as a minimum, the level of safety for a landfill for hazardous wastes, in accordance with the applicable National Standards. It was constructed with self-hardening mud and with the installation of an HDPE geomembrane. The HDPE liner of the cut-off wall was then sealed to that of the capping to obtain the complete encapsulation of the contaminated soil. A system of piezometers allows the monitoring of the cut-off efficiency measuring the fluctuations of the groundwater table and testing the chemical contents. Some wells installed within the contaminated areas will contribute to guarantee the full efficiency of the system in case of state of emergency, controlling the water-table level inside the confined areas.

Jan 1, 2006

By S. Kim Juniper

"This presentation aims to serve as a primer on conservation, research and regulatory organizations interested in the environmental impact of deep-sea mining. It will also consider a recent, early-stage proposal for an experimental SMS mining operation aimed at increasing our understanding of mining impacts and ecosystem recovery.Over the past 5 years, as deep-sea mining has been moving closer to reality, it has attracted growing attention from deep-sea biologists, conservation groups and operators of deep-sea research vehicles and observing systems. Several new international research organizations have emerged that have a direct interest in deep-sea biodiversity conservation, and the environmental impact of ocean mining. These include INDEEP, which evolved from the 10-year Census of Marine Life program, the Deep Ocean Stewardship Initiative that has recently hosted several high profile international meetings, and the VentBase forum of academics, industry and regulators that aims to develop environmental best practices and informational documents for all stakeholders involved in Seafloor Massive Sulphide (SMS) mining. InterRidge, currently hosted by China, represents a decades old partnership of deep-sea biologists and economic geologists who discovered the more than 100 known hydrothermal vent fields and SMS deposits on midocean ridges and in other settings of seafloor volcanism. In 2012 InterRidge formed an industry liaison group to examine how the mid-ocean ridge researcher community could contribute to the development of environmentally responsible practices for the exploration and exploitation of SMS deposits. While initial meetings with industry were promising, InterRidge members are currently debating the relative merits of sharing exploration know-how and understanding of vent ecosystems with industry, against the need to maintain their independence as stewards of deep-sea ecosystems."

Sep 1, 2014

By Alex Zapata, Miltón Carrión, Gustavo García

Pan American Silver Huaron ha decidido invertir U$S 4.3 millones en infraestructura de ventilación para la ejecución de chimeneas tipo Raise Boring que se ejecutarán en los diferentes circuitos de la mina, y que permitirán dar sostenibilidad al minado, profundizar las rampas hacia niveles inferiores y expandir los horizontes de la mina. Con los nuevos circuitos operando, la mina Huaron habrá reducido las resistencias de los circuitos de ventilación, por lo tanto, podrá trabajar posteriormente en controlar y reducir el consumo de energía por ventilación.

Sep 29, 2023

By Phil Thwaites

"The mining industry uses many types of mineral and metallurgical plants to produce saleable product from ore mined. Plant design history has left current operations with a mixture of manual operation and various forms of automated process controls. Consequently, we typically see high variability in the continuous operations together with a shortfall in the attainment of full capacity, or higher utilization of consumables.At a level of best practice, “Operational Performance Excellence” focuses on process control, using automation and control systems to deliver process optimization. This more sophisticated delivery is a great deal more difficult than the first stage of equipment selection / installation. It includes the appropriate selection of the right instrumentation, control system, key process knowledge, individuals with a solid control engineering background/experience, and the essential backing/ support of the operations management team together leading to higher value delivery. Robust solutions can be realized, considerably minimizing process variation, thus leading to process optimization. This approach results in an easier, efficient and safer process while providing considerable returns for the plant owners.How variable are your processes, and do you maintain optimized process performance with dedicated resources, modern instrumentation, ‘best practice’ control systems and performance monitoring tools? In this lecture, these questions and their possible answers are discussed.357"

Jan 1, 2013

By Jon C. Volkwein

The U.S. Bureau of Mines conducted a study to assess the impact of a directional water spray system on a unique single inlet dust scrubber on a low-profile mining machine. Tests were conducted in a full-scale model mine using a continuous mining machine. Tracer gas was introduced at the face and concentrations of the tracer gas were monitored at the face and in the return. Various parameters tested included mining position, depth of cut, brattice setback, and combinations of scrubber, and directional or symmetrical sprays. Results indicated that either water spray configuration improved the ventilation effectiveness of the scrubber by a factor of 2 to 3. Average face ventilation effectiveness (FVE) values for all testing of the scrubber and directional sprays were 0.95, versus 0.37 for a standard 20-ft blowing curtain without sprays. No FVE values were less than the standard 20-ft blowing results.

Jan 1, 1989

An integrated palynological and sedimentological investigation of four wells from the eastern margin of the Gippsland Basin has resulted in a scheme for classification of palynofacies in this area. Thirteen different palynofacies assemblages are recognised and assigned to particular environments based on the enclosing sediments, which range from alluvial, through coastal barrier to continental shelf environments. Close correlation is observed between the interpreted energy regime of the palynofacies assemblage, and that of the enclosing sediments. Assemblages characterised as reworking surfaces can be correlated with unconformity producing events (ie tectonic activity associated with the opening of the Tasman Sea), and some of the minor eustatic sea level Changes.

Jan 1, 1992

By P. Yu, L. X. Liu

"A mechanistic model for tumbling mills was developed during PhD studies at the JKMRC. The concept was presented at the IMPC of 2014, followed by progress in a sub-process of the model presented at the IMPC of 2016. Additionally, a number of papers on the sub-models and breakage function have been published. This paper provides a consolidated summary of the outcomes and status of the model. The overall model structure is presented along with the sub-models such as appearance functions, breakage rate functions, energy distribution, transport, and multicomponent grinding interaction model. The strengths and capabilities of the model structure as achieved to date are presented. The gaps in knowledge and sub-processes are also presented, providing a guide to the areas that require further research and development. It is proposed that the approach developed in this paper provides a structure that can accommodate future mechanistic, dynamic mill model evolution that can incorporate the latest research outcomes and provide a platform to test modelling improvements. This can assist in substantially improving the predictive mill modelling capability in the industry, the importance of which should not be underestimated for this workhorse of mineral processing.INTRODUCTION Grinding is almost the largest single energy-consuming process in the mineral processing industry, which was estimated that about 0.2% of global, and 1.3% of Australia’s electricity is consumed by comminution of gold and copper ores (Ballantyne and Powell, 2014). Although there are some relatively new grinding mills, such as stirred mills, vibrating mills and HPGRs (High-Pressure Grinding Rolls), etc., tumbling mills, as the traditional grinding facilities, are more extensively used."

Jan 1, 2018

By M. E. Rossi

All large-scale applications of conditional simulations intend to benefit from the ‘correct’ (or’ accurate’) characterization of uncertainty, adequately describing the variability observed from the data and its impact on the final objective. This paper discusses a number of relevant issues that highlight the extent to which, in reality, a model of uncertainty is dependent on the random function model chosen. Often in the presence of large number of conditioning data most available random function models will provide similar models of uncertainty. When conditioning is scarce, the resulting models of uncertainty will vary more widely, since the final output will depend mostly on the underlying assumptions of the model chosen. The application described in this paper is taken from a large porphyry Cu operation in northern Chile, and it demonstrates the impact of several variables on the resulting models of uncertainty. In particular, some of the decisions involved include the number of conditioning data and the underlying Random Function model used (Gaussian or indicator-based). Also, implementation-specific parameters must be decided upon, such as grid size used, random number generator, simple or ordinary kriging, multiple-grid simulation, and simulation of irregular three-dimensional bodies (as opposed to regular grids). Some practical guidelines are proposed to deal with these decisions.

Jan 1, 2003

By Samuel S. Wyer

THE following description of methods for conducting gas-producer tests is probably the first attempt to give the subject an analytical, thorough and comprehensive treatment. In some cases where tests have been made, the methods have been so unsystematic and ambiguous that it has been impossible to secure comparable results. To eliminate this difficulty, the following provisional code of gas-producer tests-which has some resemblance to the code of boiler-trials of the American Society of Mechanical Engineers-has been developed. The primary object in testing a gas-producer is to determine whether the producer is working satisfactorily or, what is the same. thing, to see if the efficiency is as high as it should be with the type of producer in question, and also to find out if the composition of the resulting gas is adapted to the work it has to do. In order that the test shall be of any value, it must be thorough and comprehensive, and must be conducted with skill and care. When so conducted, the test will reveal the economy of the producer; and, by making suitable changes, the efficiency will often be increased very much. As a result of the tests made by Jenkins, 1 the efficiency was raised from 56.2 to 71.2 per cent. This shows the large saving that may frequently be made in the fuel-consumption by studying the results of a careful test.. The log of the test, given in Fig. 1, shows that, just as soon as the temperature became regular, the percentage of CO, decreased and that of CO increased.

Mar 1, 1905

By Reginals W. Burroughs

Diatomaceous or infusorial earth, also called diatomite; fossil meal, or kieselguhr, is derived from the lowest form of vegetable life, the unicellular alga:. It consists of the siliceous remains of extremely minute aquatic plants, which exist in both salt and fresh water. Light i~ a prerequisite to their development. These very small particles secrete silica in much the same way that molluscs secrete lime to form their shells. The diatoms at death sink to the bottom of the body of water in which they lived, and the organic matter gradually decays and is washed away, leaving the skeletons. Thousands of years are required by this means to develop bed5 of sufficient thickness to be of commercial value. The siliceous remains vary in size according to the species, but all are very minute and, as a general rule, they can be identified only under a high-power microscope. Over one thousand types have been distinguished and named. They are all composed of a hydrous or opalescent form of silica, with silica content ranging from seventy to ninety-five per cent. Magnified, they present an attractive sight, a very fragile structure with many interstitial openings known as cells. Many of them consist of two parts, defined as valves, held together by means of a girdle. Certain species, belonging to the Pinnularia family appear as a long comb, in half longitudinal section. The spaces between the teeth are the cells. This particular genus is very common in Nova Scotian deposits.

Jan 1, 1928

By D. Xie

An in situ gravimetric technique based on wetting and capillary action principles has been used to investigate the wetting and penetration of synthesized alumina samples and commercial magnesia spinel refractories by CaO-SiO2-Al2O3-Fe2O3slags. Synthetic slags of 40CaO-40SiO2-20Al2O3 (in weight per cent) with 0 to 9 weight per cent Fe2O3were used and the experiments were conducted at temperatures 1370 to 1470ºC under argon. The contact time between the sample and the slag was 30 minutes. The results show that the wetting and penetration are enhanced by the iron oxide addition in the slags. Addition of Fe2O3from 0 to 9 weight per cent resulted in a significant increase in the slag penetration into the magnesia spinel refractory by a factor of about 7 and a moderate increase in the synthesized alumina by about 60 per cent. The addition of Fe2O3enhanced the wetting (??cos?, where ? is the surface tension of the slag and the contact angle between the slag and the refractory) by 5 to 18 per cent. An increase in temperature from 1370ºC to 1470ºC resulted in a significant increase in the penetration of a 6 weight per cent Fe2O3slag in the alumina and magnesia samples by a factor of4 to 5 and a decrease in wetting by approximately 30 per cent. Keywords: refractories, slag penetration, wetting.

Jan 1, 2004

By W. S. Sadik

This paper presents the ventilation design for an underground testing facility in a salt medium. The underground workings consist of two-12 ft. (3.66 m) diameter watertight shafts and approximately 6000 ft. (1830 m) plus of drifting. These facilities are designed for the purpose of providing access for an in-situ testing of a salt horizon in which a variety of hazardous and non-hazardous materials could be temporarily stored or permanently deposited. The ventilation system includes a design basis for gassy mine conditions and provides for the option of bulk air cooling and heating.

Jan 1, 1988

By Leon H. Nelson

Several factors which affect the segregation and solidification of killed hot-topped steel ingots are: (1) pouring temperature, (2) volume in the hot top, (3) taper in the ingot, (4) pouring rate by varying the nozzle size, (5) segregation of several elements, (6) moving ingots before completely solidified. In most of this discussion, segregation will be measured in terms of carbon variation only. All the data given are results on S.A.E. 1040 analysis of fully killed steel direct-poured in hot-topped molds giving 20-in, square ingots. Thus the variables of analysis and ingot size and contour are eliminated. Segregation results are all on the rolled-bloom size, not on the ingot itself. They are results from plant-control work and not results of special research on ingot segregation. Pouring Temperature The temperature (or, more correctly, the amount of superheat above the liquidus-solidus) of the steel entering the ingot is, of course, one of the most important factors influencing segregation and solidification. Table 1 gives the average segregation of a number of heats of S.A.E. 1040 steel with normal pouring temperatures of 2775" to 2825" F. The table also gives some data on segregation in hot heats (pouring temperature 2840" to 2870" F.) and in cold heats with some skull (poured at 2725" to 2760" F.). The results in Table 1 are on steel ingots with 20-in. square cross section and 60 in. long to the hot top. The ingot weighs 7100 lb. and the hot top contains 14.3 per cent of the total ingot volume and 11.2 per cent of the total ingot weight. The results are from drillings after rolling the ingots to bloom size. Segregation results obtained on the bloom are probably not as great as they would be in the ingot itself, since heating the ingots for rolling can perhaps cause some migration of carbon from regions of high and low carbon to those of average carbon content.

Jan 1, 1937

By A. L. Garassino

Dans cet article on parle sortout de l'approche de calcule pour les pieux charges horizontalement avec particuliere reference aux curbes p-y et è une solution semi-empirique qui prende en consideration les variations typiques du module du sol avec la deformation obtenue par les données expérimentales. 1. INTRODUCTION The analysis of the piles under lateral loads depends very strictly from the pile stiffness and geometry, from the soil type and from the strain field. Different approaches were adopted in solving the problem. Some Authors developed methods for estimating the ultimate lateral resistance of piles and pile groups by conventional static approaches, as the Brom's widely known (1964) or by the plane strain solution developed by Davis (1961) or by empirical engineering con­siderations l

Jan 1, 1994