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By G K. N Subasinghe

Metallurgists operating Knelson Concentrators (KC) often rely on manufacturerÆs recommendations for selecting operating parameters, such as fluidising water flow rate and cycle time. Recent studies have shown that these parameters are not only dependent on the machine parameters but also on the feed characteristics, such as size distribution of the gold and gangue particles and the composition of its constituent minerals. It is known that a particle entering a KC initially traverses a circular path within the bowl. For a particle to maintain a given orbit, the required centripetal force must be supplied by external means. It has been argued that this centripetal force, which is dependent on the mass of the particle, its radial position and the rotational speed of the bowl, is provided by the fluid drag force created by inwardly moving fluidising water and the BagnoldÆs force created by the particle/particle collisions. Depending on the fluidising water flow rate, one of two situations can occur where the porosity of the bed increases or decreases, which influences the amount of material retained within the bowl. The amount of material of a given size and density retained in the bowl is thus dependent on the extent of the centripetal force provided. Based on the above concept, a criterion that can be used to predict the amount of material recovered in the bowl has been derived and validated by experimental data. It may also be construed that this criterion demarcates the transition of the bed from a packed-bed state to a fluidised state. By identifying the transition values for the different constituent mineral particles in the feed, it is possible to estimate the optimal fluidising water flow rate that would maximise gold recovery while minimising gangue recovery. In addition, the kinetics of gangue displacement by incoming heavy mineral particles were also studied using synthetic mineral mixtures. The experimental data suggests that this process follows first order kinetics and that the build-up of heavy mineral reaches a maximum. A model has been proposed to predict the optimal batch cycle time for a KC in terms of the feed characteristics and machine operating parameters.

Jan 1, 2006

By G. G. Li

"A dynamic ventilation-modeling package, VREX, was used to simulate the mine activities through tracking the equipment movements in underground workings and determine the airflow demand for a new production scenario in a ventilation-on-demand (VOD) system. It incorporates the mine development data from a discrete event simulation and balances the ventilation network using the CANVENT ventilation solver. A case study was performed to demonstrate the capabilities of the software, evaluate the performance of the network and determine the potential energy savings for implementing VOD in a deep mine operation.INTRODUCTIONThe ventilation cost of an underground mine can be significant—up to 50% of the mine’s energy consumption could be used to run fans and provide heat/refrigeration to meet the specified production environment for workers and equipment. The VOD system has proven to be more efficient in operating the fans and supplying the amount of air corresponding to the mine activities taking place in underground workings (Hardcastle, Kocsis, & O’Connor, 2006). In order to properly solve and evaluate the VOD system, a dynamic ventilation modeling software VREX—the ventilation rules engine has been developed to simulate the mine activities and determine the airflow demand for each production scenario within an operation period (Dasys & Cameron, 2011).VREX is a decision support tool, backed by the CANVENT mine ventilation solver (Li, Kocsis, & Hardcastle, 2009), for determining the outcomes of network configuration changes over time. The software incorporates the mine development data with ventilation modeling through the discrete event simulation (DES) performed by SimMineTM. As it simulates the air requirements for different vehicles and activities, VREX can evaluate both the performance of the ventilation system and the potential economic benefits of making operational or technological changes (Pritchard, 2010). For example, the model can be used to assess the economic and environmental impacts arising from modifying regulations to support the use of electric or lower emission vehicles. The combination of DES and ventilation modeling provides a new technology to generate the production scenarios according to mine schedules and activities and to determine the potential benefits for various levels of ventilation control, such as time interval and work shift change."

Jan 1, 2019

By Susumu Okabe, Etsuji Kimura

"The Mitsubishi Continuous Copper Smelting and Converting Process is the typical applications of injection metallurgy to nonferrous metallurgical operation, where the top blowing multiple lance system is employed for the continuous feeding of the raw materials and reaction gases into the molten bath. This results in an effective dispersion of the reactants into a strongly agitated bath. These are considered as the major advantage of the process with respect to the high production efficiency. On the other hand, however, the strong agitation may cause a considerable amount of refractory wear, and the melt splash generated by the lancing may also have negative effects on the productivity, i.e. the increase in the refractory wear, the metal loss, the heat loss, and the accretion growth, etc. Therefore, the optimization of the blowing condition as wen as furnace design is very important to achieve a stable and efficient operation, and fundamental understanding of the injection, agitation, and splashing is badly needed.In this paper, fundamental aspects of the Mitsubishi Process regarding injection, especially splashing phenomena, are discussed. The splashing on a vertical plane caused by the top blowing gas injection onto liquid surface was investigated through physical model study. As a result of the study, the splashing rate on the furnace wan was wen correlated with the physical properties of the bath materials, gas velocity, cavity shape, lance/wall distance and ceiling position. Obtained equations were compiled in a computer program and have been successfully applied to the evaluation of the furnace design. IntroductionInjection metallurgy is an application of gas/solid-in-liquid dispersing operation to the metallurgical processing, and has been widely adopted in various fields in order to improve their efficiency or productivity. The dispersed small particles of gas or solid materials in the liquid phase result in increased interface area, and injected momentum causes an agitation and enhanced heat and materiel transfer. Typical examples of injection metallurgy are LD converter for steel making, PS converter, Noranda process, Isasme1t for copper making, and Mitsubishi Material's continuous copper smelting and converting process, and so on."

Jan 1, 1996

By Carvalho A. Felipe de

The search for environmentally friendly and cost-effective methods for gold extraction has been undertaken in order to provide alternatives to the use of cyanide leaching in the gold industry. Among such alternative reagents is the combination of chloride and hypochlorite ions due to their oxidation of metallic gold and its complexation. Therefore, the current work aims at investigating gold leaching from an oxidized material by means of a solution comprising calcium hypochlorite and sodium chlorite. The sample used in the current research contained 66.1% Fe2O3, 20.4%SiO2, and 35.7 g/t of Au. In addition, XRD and SEM-EDS analysis revealed iron oxide, quartz and muscovite as the main crystalline phases in the sample. For comparison purposes, cyanidation of the oxidized material resulted in 90% gold extraction in 24 h. The reference conditions for the leaching tests with the chlorite-hypochlorite system were: particle size −37 μm, solid/liquid ratio of 10% (w/v), 10 g/L NaCl, 10 g/L Ca (OCl)2, pH 5–6, 3 h of leaching. The effects of the: (i) Ca(OCl)2 concentration, (ii) NaCl concentration, (iii) pHrange and (iv) the effect of pulp density in the extraction of gold were assessed. In addition, the stability of the hypochlorite solutions (OCl−) was investigated. The ideal concentrations of Ca(OCl)2 and NaCl were determined as 25 g/L and 15 g/L, respectively, whereas the optimal pH range was 4–6. Under these conditions, the final gold extraction reached approximately 84%. By varying the solids content of the pulp (10%, 20% and 30%), it was observed that the lower solids value resulted in greater gold extraction (84%). The degradation of the hypochlorite solution and the possible catalytic effect of the presence of the solid were evidenced. To sumup, in the experiment, high gold extractions were achieved in shorter periods of time (3 h), as compared to the cyanidation of the same sample. On the other hand, itwas necessary to use significant amounts of the reagent due to hypochlorite instability at the pH conditions recommended for high gold extractions.

By Kari Niiranen, Patrick Krolop, Viktoria Töyrä

Luossavaara-Kiirunavaara AB (LKAB) operates an iron ore mine, three beneficiation plants and three pelletizing plants in Kiruna, Sweden. The current methods of separation in the beneficiation plants are wet low intensity magnetic separation (WLIMS) and reverse apatite flotation, where the WLIMS stage is regarded as the crucial part of silica separation from the ore. Currently, the high-grade iron ore deposit of Kiirunavaara has a low grade of silica in situ, of approximately 3.0% SiO2, but the silica grade is expected to increase in the deeper parts of the deposit with a complex silicate mineralogy. An increasing silica grade will affect especially the production of direct reduction pellets (LKAB DR Oxide Pellets), one of the main products of LKAB in Kiruna with an average silica grade of under 0.75% SiO2. The silica grade in the magnetite concentrate is normally limited to a maximum level of 0.55% SiO2 in order to achieve the required chemical composition in the pelletizing process. In order to study the possibility to reduce silicate content in the magnetite concentrate (pellet feed) in the beneficiation plants in Kiruna obtained by wet low intensity magnetic separation (WLIMS), enlarged mineral processing test work was carried out in the LKAB’s mineral processing laboratories in 2016. The test work consisted of comminution, low intensity magnetic separation and reverse cationic silicate flotation at laboratory scale, complemented by screen analysis, chemical assays and mineralogical investigation. The results of these mineral processing test work showed that the magnetic separation is not sufficient to reduce the silica content in the magnetite concentrate, particularly in the case of the high-SiO2 ore type B2-a. The reverse cationic flotation can be regarded as a possible solution to reduce the silicate content in the magnetite concentrate obtained by WLIMS and to achieve the required silica grade of less than 0.55 % SiO2 in the pellet feed. The results of this study provide a good basis to understand the behaviour of different silicates in the existing beneficiation process. Furthermore, it serves valuable information for development of new beneficiation processes and for investment in new equipment at the beneficiation plants in Kiruna in the future.

Jan 1, 2018

By S. Shimaya, T. Maejima, M. Shimo

"The authors conducted the in-situ gas-tightness tests in a fractured rock at the Namikata underground LPG storage site in Ehime prefecture, Japan. The test consisted of two independent setups, a gas-tightness test that used boreholes, and a chamber-scale test that used a horizontal drift sealed with a concrete plug. In each test, the gas pressure was increased up to the onset of the measurable gas flow to obtain the maximum containment pressure. This paper discusses the hydraulic conditions for gas leakage initiation and the importance of the pore pressure measurement for monitoring the gas-tightness of the LPG storage cavern based on the test results.INTRODUCTIONJapanese first underground LPG storage plant was constructed by JOGMEC, the Japan Oil, Gas and Metals National Corporation, at Namikata in Ehime prefecture in granitic rocks (Kato et al., 2007). The “hydraulic sealing principle” (Åberg, 1977) that utilizes groundwater flow into an unlined cavern to prevent the leakage of gas through fractures in the surrounding rock mass was employed for storage of LPG. This paper describes the results of the in-situ tests performed at the Namikata Site to obtain information on fundamental gas-tightness characteristics of fractured rock. Two types of in-situ tests, a borehole gas-tightness test and a chamber gas-tightness test, were carried out near the storage caverns. Figure 1 shows the cavern layout of the Namikata underground storage plant and the test locations. The storage facilities consist of three caverns (W26m×H30m×L485m). The cavern crown lies at a depth of 150m below the sea level in Cretaceous granitic rock (Figure 1). Water curtain boreholes excavated from the water gallery tunnel at EL-125m level are located above and side of the caverns to prevent water drainage from fractures during the construction stage as well as during operation. The borehole tests were performed from a drilling adit excavated from the eastern end water gallery tunnel, while the chamber test was conducted at the southern edge of an exploratory drift extending from the central water gallery tunnel."

Jan 1, 2015

By Orestis Zarzouras, Amalia Giannakou, Jacob Chacko

"When designing structures in seismically active areas, foundations of critical structures are typically located away from known faults. Indeed many seismic codes prohibit construction in the immediate vicinity of seismically active faults establishing minimum setbacks from the faults. However, for long structures such as bridges, tunnels and pipelines, a fault maybe unavoidable, and fault rupture risk impossible to preclude. This paper presents a case study of a bridge foundation design that incorporates the consequences of fault deformations passing through the foundation. A series of site surveys were conducted to characterize the fault environment, and fault displacement hazard analyses were conducted to develop design displacement demands. Subsequently, numerical analyses were performed to evaluate the fault rupture-induced demands on a pier foundation in terms of displacements and rotations. Initially, analyses were performed that model the free field fault rupture propagation to the ground surface of the fault to ensure that the basic site characteristics are captured. Subsequently, the foundation elements were introduced in the model and the fault rupture is simulated again. The interaction and influence of the foundation on the fault rupture propagation is calculated, and the consequent demands and distortions of the foundation block provide a basis for structural engineers to design the bridge.IntroductionThe Izmit Bay bridge, a 3-km-long suspension bridge that crosses Izmit Bay in Turkey, is planned to be constructed in one of the most seismically active places in the world. The south approach structures for the Izmit Bay Bridge along the western side of the Hersek peninsula bring the bridge down from on the order of El. 60 meters at the South Anchorage to an elevated embankment approximately 1.3 km farther south (Figure 1). The south approach structures are located within a zone of secondary deformation around the primary trace of the North Anatolian Fault. The concept design team has developed a concept design for a “viaduct” structure that consists of 10 spans with lengths varying between 136 m and 100 m and two back spans one of 125 m, attached to the main bridge and the other of 74 m attached to the south embankment."

Jan 1, 2017

By T. Shumba

The solvent extraction section of an old Uranium Plant in the Vaal River region produced a sub-stance called Crud (Chalk River Unidentified Deposit) that formed within the aqueous/organic interface of the settler of the solvent extraction circuit. The crud was deposited together with gold tailings to the tailings dam many years ago. Previous research done on the crud confirmed that ex-posed crud leaches Mn and Ni at concentrations that are well above their acceptable risk limits as well as Zn that leaches at concentrations that are slightly lower than its acceptable risk limit. Soil washing and bioremediation technologies were employed to treat the contaminated soil. Various laboratory test work and the pilot scale studies were conducted in parallel with each other and the results of the laboratory studies were used to determine critical parameters. Four lixiviants, i.e. sulphuric acid, acetic acid, oxalic acid and ethylene diamine acetic acid were tested at three concentration levels i.e. 0.001M, 0.0001M and 0.00001M, respectively. Column tests showed that the leaching of the heavy metals increases as the soil porosity increases. Silica sand was added to increase porosity of the contaminated soil. Highest Mn removal was achieved mainly by sulphuric and oxalic acid at 0.001M at all soil levels. EDTA was significantly efficient in the removal of Ni and Zn. The recovery of heavy metals, particularly Mn, decreased as the depth of sampling in-creased. Heterogeneous bacteria and filamentous organism plate counts were conducted to evaluate the growth of the bacteria and filamentous organisms in the soil. Results showed that more organism growth took place in the bioremediated soil with a fertilizer added to it. The leaching of metals from the soil that was bioremediated in the pilot study was generally higher than the extraction of the metals from the soil that was leached with no bioremediation carried out. The results from this study suggest that the leaching of heavy metals from the contaminated soil is to a large extent dependant on the pH of the leaching solution. By increasing the soil?s porosity and bioremediating the soil, higher extractions of metals were achieved.

Jan 1, 2014

By E. Guerrini, M. Maccagni, J. Nielsen

"Lead is the most important material able to meet the current demand for energy storage. The lead acid battery is reliable, efficient and inexpensive. Continuous developments in battery construction are providing improvements in all aspects of the batteries’ performance. The lead acid battery is both the main lead product and the main raw material for lead production. More than half of the lead produced is from secondary smelters where batteries are the most important feed material. The environmental pressure on lead production has been increasing for many years, and continues to become stronger and stronger. The lead production processes and technologies themselves will require updating to meet the new regulations. Although they are very strict now, they will become even more so and current technologies may not be sufficient. Because recyclability is a strong point for the lead acid battery, the secondary smelters need to reduce the environmental impact as much as possible. In recent years, the secondary smelters underwent impressive changes in this direction, but some more improvements are possible. Electrochemistry can offer a step change improvement in making secondary lead production more environmentally friendly. Engitec has developed an electrochemical process base on a very high current density (high productivity) cell using an inexpensive electrolyte and at a relatively low cost. In this paper, the latest update on the technology is provided. INTRODUCTION The lead acid battery is considered the “walking dead” by some new technologies trying to replace it. It has played and will continue to play a very important role in our lives because it is inexpensive, fully recyclable and the existing lead and the mine reserves guaranty enough material for the extended future. According to the life cycle, the lead acid battery is the cheapest and the most effective system to store energy. Lead is practically a close loop where lead battery production consumes more than 80 % of the produced lead but contemporarily it is the most important raw material for the production of metallic lead. In fact, nowadays, the secondary production has overcome primary production and this trend is expected to continue. Primary lead is the make-up material for the existing battery production and the source of lead for the construction of the new ones."

Jan 1, 2018

By Dandan Jian, Christian Karcher

Information of liquid steel flow patterns inside the mold may be obtained from the velocity at the free surface (meniscus). This meniscus flow may be measured using the contactless electromagnetic technique termed Lorentz force velocimetry (LFV). It is based on the measurement of Lorentz forces acting on a magnet system when an electrically conducting metal melt interacts with the field lines stretched by the magnet system. Force sensor and the magnet system form a so-called Lorentz force flowmeter. In this paper we present a series of model experiments that demonstrate the feasibility of using two identical flowmeters that are arranged in a certain distance one behind the other. In this case, surface velocity may be determined by just cross-correlating the two force signals recorded by the two sensors. This technique is called time-of-flight LFV. A special prototype of a respective measuring device, called meniscus velocity sensor (MVS), has been developed to measure local free-surface velocity. In the present paper we describe experimental results of respective measurements in the model test stand LiMeSCo (liquid metal surface velocity correlation). To check the potential of the time-of-flight technique, in a first step we measure surface velocities during solid-body rotation of metallic substances. We observe that small modulations in the signals that are due to the natural unevenness of the solid body can be used to determine surface velocities. In a second step we apply the time-of-flight technique to liquid metal free-surface flow. Here we use the low-melting eutectic alloy GaInSn as a test melt. In this case we observe that the cross-correlations between the signals are much rarer and much weaker than in the solid-body experiments. We conclude that the presence of the localized magnetic fields, produced by the permanent magnets of the flowmeter, give rise to intense deformation of the free surface and the creation of surface waves. The field acts as a magnetic obstacle. We observe that the flow velocity is decreased right underneath the magnetic field and is accelerated in the side regions. This magnetic obstacle effect may restrict the determination of the local surface velocity in application.

Jan 1, 2012

By M. Marchese

It is no secret that scarcity of fresh water is an issue that at a global level in the years to come will have a major impact on the business landscape. A number of projects, beyond the mining sector, could remain on paper only due to this. At the same time, this situation is seeing the rise of new business opportunities, such as development of technologies for more efficient usage of water, water recycling, and desalinization of sea water. Despite that most of Chilean mining facilities are located in the driest area of the world, business has developed strongly and actively for more than a century. However, the negative effect on the water reservoirs and the environment is, lately, resulting in the reduction of the authorized water rights. Holding Water Rights for any given volume does not guarantee that the resource will be available when needed. A recent report from the United Nations on global climate change indicates that global warming can be directly related to changes in the natural and human environment. Chile would not be an exception. The reduction in snow levels in the high Andes and reduced rainfall during the so called "Bolivian winter", have directly affected the replenishing of the underground water reservoirs in the lower parts of the valleys, where most of the extraction of the resource takes place. Mining facilities shall be designed to reduce potential environmental effects, using proven technologies, and considering the best practices available. These measures shall constitute a complete structural framework for the environmental impact assessment (EIA) of the Project. The measures to prevent and mitigate the impacts on the water resources shall be considered during the design stage of a mining project. Current and future mining projects in Chile are conscious that the increasing pressure on the limited water resources is becoming unsustainable, and are already facing the water scarcity and social pressure by implementing sea water desalination plants, including long pressurized pipelines to the mine sites (e.g. Escondida, Candelaria, El Morro, Regalito). This paper presents, in summary, an analysis of the present and potential future scenarios.

Jan 1, 2007

By A. Morrison, D. Mesa, P. R. Brito-Parada

"Froth flotation is the most widely used mineral separation technique. It is based on the relative hydrophobicity of valuable and gangue particles. In a flotation tank, two distinct zones can be identified: the pulp and the froth. The pulp is a turbulent region in which hydrophobic valuable particles attach to air bubbles while hydrophilic gangue particles remain in the slurry. As the particle-laden bubbles rise, a mineralised froth zone is formed that overflows as a concentrate. Although the process is more than a hundred years old, there remain many aspects that are not completely understood, particularly for the froth zone. Thus, the rules governing the design of flotation tanks tend to focus on pulp zone parameters, which are largely based on operating data. An example of this is the design and operation of impellers. These tend to be designed paying attention to hydrodynamic phenomena in the pulp zone, but their effect on the froth zone has not been completely addressed. The role of impellers in a flotation tank is to break the air bubbles in order to generate smaller ones and to provide an environment that enables the collision between those bubbles and the particles in the slurry. This usually creates turbulent regimes that can affect the pulp-froth interface, destabilising the lower regions of the froth and affecting the overall performance of the process. Different impeller designs and retrofit modifications have been proposed in the past, addressing some of those issues. However, there is no systematic study of the effect of different impeller designs on the bubble size in the pulp and its links to the stability of the froth. This work tested the impact of an impeller designs combined with the use of a stator on the performance of an 87 litres continuously operated laboratory-scale flotation tank, with a focus on bubble size in the pulp and froth stability. The results showed that the implementation of a stator system decreased bubble size and increased froth stability. That resulted in an increase of mass pull, measured as a proxy of metallurgical recovery."

Jan 1, 2018

By T. S. Lundy, J. I. Federer

Chemically purified Zr95and Cb95 have been used in determining self-diffusion coefficients in the bcc phase of iodide zirconium over the temperature range of 900o to 1750°C. The temperature dependence of the diffusion coefficients could not be described by the usual Arrhenius-type equation over the entire temperature range. Values of the apparent frequency factors (D0)a and activation energies (Q)A for ZR95 varied from 4.8 x 10-6 to 2.5 x 10-2 sq cm per sec and 20,700 to 46,900 cal per mole, respectively, between 900°and 1750°C. Similarly, for Cb95, values of (Do) a and (Q)A varied from about 2.4 x 10'5 to 0.25 sq cm per sec and 26,500 to 56,800 cal per mole, respectively. The data may be described in terms of the a to ß transition temperature of 1136 °K and the absolute temperature of the diffusion anneals by the following eauations: SEVERAL studies on the diffusion of Zr95 in zirconium have been reported.1"5 The values of the constants contained in the usual Arrhenius-type equation for describing the temperature dependence of the diffusion coefficient, D = Do exp [- Q/(RT)], are summarized in Table I. The reported values of Do, the frequency factor, and Q, the activation energy, are seen to vary by factors of about 60 and 1.6, respectively. Examination of the data from any one study indicated reasonable consistency of measurements. The large discrepancies of over-all results, therefore, cannot be explained on the basis of experimental scatter. One possible explanation for the differences in results could be a varying impurity content of the zirconium. Another possibility is that the radioactive daughter, Cb95, influenced the values of some of the determined diffusion coefficients. Therefore, the first of the three purposes of this study was to reconcile the large differences in diffusion results that have been obtained. Several empirical relations have been proposed to relate the diffusion coefficients in solids with physical properties, such as the absolute melting point, the heat of fusion, and the heat of sublimation.

Jan 1, 1963

By Viviane Tavares

The liquid crystal display (LCD) are currently known by its vast application in electro ? electronic devices, amongst them can be detached the devices of TV, laptops, electronic date, calculators and even though the mobile telephones (mobiles). The mobiles are changed more frequent of the TV for example, this happens due to the technology advance. With the constantly mobile exchange, the batteries, printed circuit board and liquid crystal display accumulation its become an environmental problem. To minimize the environmental impacts caused by mobile telephones residues are considered the segregation process of the LCDs main components, to goal to recover the recycle material. This process involves the use of treatment ore techniques with disc, hammers and balls mills. The process with best efficiency (about 98%) of LCD glass release was the hammers mill. The glass recovered can be used in the glass recycling and the sand substitution in the production of concrete blocks.

Jan 1, 2009

By Michaela Dina Stanescu, Emilia Visileanu, Eftalea Carpus

"The recovery and reintroduction into the economic circuit of the textile material resources must be considered as component parts of the strategies of harmonizing the relationships between the economic growth, consumption of natural resources and environmental protection of the existing socio-economic system.The waste recovery for ensuring a sustainable development is a major concern of all industrial researches. In the textile domain, the concern in this matter is becoming more evident. An important role in manufacturing textile products it has the notion of eco-design, which has grown considerably over the last twenty years with increasing awareness of environmental and social problems in the industry.Introduction“Humanity must learn from the global financial and economic crisis experience""- is the conclusion of the policy makers who should develop a strategy designed to reinvigorate the economy and make possible an"" intelligent, sustainable and favourable to inclusion” growth, by a better coordination of national and European policies.The new vision for social market economy is based on three priority areas: smart economic growth, the development of an economy based on knowledge and innovation; sustainable economic growth, the promotion of a competitive economy with low carbon emissions and an efficient use of resources, as well as an inclusive economic growth, the promotion of an economy with high degree labour employment, which would generate social cohesion. The recovery and reintroduction into the economic circuit of the textile material resources must be considered as component parts of the strategies of harmonizing the relationships between the economic growth, consumption of natural resources and environmental protection of the existing socio-economic system.The waste recovery for ensuring a sustainable development is a major concern of all industrial researches. In the textile domain, the concern in this matter is becoming more evident. It is obvious that at the origin of pollution there are the technological processes of textile processing with impact on air, water, soil, as well as the storage processes. In all phases of obtaining a product, a series of secondary products and textile wastes with impact on the environment occur. The product used becomes also a factor of environmental pollution, which in most cases fails to assimilate."

Jan 1, 2012

By C. T. Wiliams, John B. Bush, John Lamb

"THE TOWN OF HEDLEY is in the valley of the Similkameen River, about 200 miles east of Vancouver and 25 miles north of the International Boundary between British Columbia and the State of Washington. The main ore deposits are located on Nickel Plate Mountain, northeast of the town.The outcrop of the Nickel Plate system of orebodies is at an elevation of 5,900 feet. It was discovered in 1898 by prospectors and sold in the following year to the Marcus Daly interests of Butte, Montana. Production commenced in 1904 under the name of Daly Reduction Company. In 1909 control passed into the hands of the Hedley Gold Mining Company. Operation of the mine continued until 1930, when exhaustion of known ore reserves forced it to close. Upon the recommendation of Paul Billingsley (3) the mine was optioned by the 1. W. Mercer Exploration Company in 1932. Production began once more in 1934 under the name of Kelowna Exploration Company Limited, and was practically continuous until August 1955, when the mine was again shut down. The name of the latter company was changed in 1951 to Kelowna Mines Hedley Limited.The Mascot Fraction, a small wedge-shaped claim lying astride the Nickel Plate orebodies, was mined by Hedley Mascot Gold Mines Limited between 1935 and 1949. The geological setting and structural control of ore are essentially the same as in the adjoining Nickel Plate Mine.Total production from all operations on Nickel Plate Mountain to the end of 1954 was approximately 3,800,000 tons of gold ore, with a gross value in excess of $48,000,000.General GeologyNickel Plate Mountain occupies the gentle westerly dipping limb of an asymmetrical anticline, the axis of which trends northeasterly. The rocks are composed of a thick pile of Triassic limestone, limy argillite, and quartzite, -resting on a flattish floor of granodiorite near the base of the mountain. Associated with these sediments is a host of porphyritic sills and dykes of gabbro-diorite composition. In the mine area east-west brown soda-rhyolite dykes and north-south black andesite dykes crosscut all the other formations and the ore, probably following steep later fractures."

Jan 1, 1949

By ARCH L. FOSTER

The rapid increase in the mmber of automobiles during the last 25 years has resulted in the insistent and growing demand for better roads of more permanent construction. Some form of State license for the operation of automobiles has been in effect almost from the time of the first "self-propelled" vehicle, and some part of the revenue derived from the sale of these licenses has been applied to the maintenance and construction of roads. However, to obtain funds with which to build their present highway systems, the individual States have resorted to the taxation of gasoline. The first State to adopt a gasoline tax was Oregon, the law becoming effective February 25, 1919. By 1928, all of the States except two had levied taxes on gasoline at rates varying from 2 to 5 cents per gallon. New York and Massachusetts passed gasoline tax laws which became effective in 1929. Regulations governing the quality and the methods of handling gasoline and other petroleum products sold in the States have also been adopted by 29 States; many of these laws antedate the adoption of a gasoline tax. The variations in motor fuel speci- fications and methods of test have been pronounced in the several States. The Bureau of Mines, in making certain technical studies of the rasolines marketed throughout the United States, the results of which are reported in its semiannual motor gasoline surveys and other reports, has had occasion to obtain and compile all of the present (April 1, 1931) tax and pection laws of the several States which relate to motor fuel and other petroleum products. To facilitate the use of this material and to obviate the need in most cases of reading the complete text of the laws as published by the States, the pertinent information was arranged in tabular form for cly reference. 3 Although digests of States gasoline tax laws' are available and copies of the complete laws can be obtained from the State agancies in charge of the enforcement of gasoline tax and inspection laws, it is believed that

Jan 1, 1932

By J. P. A. Hortley

In conventional electrolytic copper production, looped copper starter sheets, on which the copper is deposited, are supported by hard-drawn copper bars. These bars have cross-sectional areas of between 1 and 1.4 in2. The suspension bars serve two purposes: firstly to support the cathode, which can weigh up to 150 kg, and secondly to introduce the electric current. IYI examined these two requirements in detail to see whether a better design could be achieved. Considering firstly the current carrying requirement, it wee noted that under normal refinery conditions, each cathode carries between 400 and soak. If one applies the generally accepted rule that 1 in of copper can carry 1000A4 a suspension bar need theoretically contain only 1/2 in2 of copper. This contention is supported by the fact that the 500A current passed through the cathode also appears to pass quite satisfactorily through the two support loops, which have a cross-sectional area of approximately 0.35 in 2. Turning now to the strength requirements, the cross-section of hard-drawn copper bar required to support a 150 kg cathode is relatively small, and easily met by the present designs. It is not, however, the static load applied by the 150 kg cathode immersed in the electrolyte which causes the damage to the hard-drawn copper, or even the increased static load of a 100 kg man standing on one foot in the centre of the bar; the damage is actually caused by the dynamic loads applied to the bare when they are dropped, thrown into containers, lowered too rapidly into the cell, or otherwise mistreated. The important requirement is therefore that the bar does not permanently bend. Its proof stress of limit of proportionality, rather than the amount that it deflects under static loading, should be the strength criterion. With the hard-drawn copper normally used for the manufacture of suspension bars, it has been observed that the copper becomes annealed during use, particularly at the end of the bar where the current is introduced. Thus, after a relatively short time, the cathodes are in effect being supported by annealed copper bars.

Jan 1, 1978

By C. E. Schmidt

Homestake crushing and grinding, practice-was completely revised during the period of 1951-1953. During the conversion, both crushing plants at the head frames the Ross and the Yates, were changes at each plant involved replacing the two 8K gyratories with a rebuilt, The flow sheet single thirty inch gyratory for primary crushing to four inch. The gyratory discharges to a seven foot Symons standard cone crusher set at 1-1/8 inch opening. The cone discharge goes to Tyrock screens fed by vibrating feeders. Screen openings, are l/2 inch by 5 inches: at the Ross. Plant, and 3/8 inch by 5; inches at the Yates. Screen oversize goes to a seven foot Symons cone brusher converted to the short head type; the crusher setting is 5/16 inch. Crusher, discharge; is closed circuited with the Tyrock screens, The above crushing installation delivers a minus 5/8 inch rod mill feed to the mill bins. The crushing revision eliminated the-180 heavy South African type stamps, which had previously reduced the 2 inch crushing plant product to a minus 5/8 inch feed for the 10 rod mills, and 8 ball and pebble.; mills, other revisions in the mill flow sheet, resulted in 3 identical units of about 1350 tons per day, capacity per unit, Each unit consists of an open, circuit 6 foot by 12 foot rod mill, fed from two 24 in by 48 inch vibrating feeders of the four feeders available per unit. A gathering belt delivers the ore discharge of the feeders to the Transportoweigher, which in turn discharge s, into the rod; mill feed spout. Rod Mill discharge is the feed for the 9 foot by 11 foot ball mill, The ball mill is closed circuited with a 16 foot by 30 foot Dorr Classifier. The Homestake make amalgamator, for coarse gold recovery in the ball mill circuit, made' necessary a 36 inch spiral conveyor between the classifier rake discharge and, the combination drum and double scoop feeder on the ball mill See Figure l - the flow sheet of the two stage grinding units.

Jan 1, 1958

By V. A. Marple, K. L. Rubow

"In our laboratory several impactors have been developed in the past which have penetration characteristics that approximate that of the ACGIH or the British MRC respirable curves. In these impactors the large nonrespirable particles are collected on an impaction plate of a multiple round nozzle stage where the nozzles are of different diameters. The principle for designing a respirable cut impactor is quite simple in that the respirable curve is divided into two or more segments and the nozzles are designed with the correct diameters and number of nozzles to have collection characteristics with 50% cutpoints at the center of each segment. The particles not collected on the impaction plates are then collected upon a filter. These particles represent the respirable fraction of the aerosol. Therefore the respirable curve is approximated in a stepwise fashion with the approximation becoming better as the respirable curve is divided up into increasing numbers of segments. It has generally been felt that three segments is satisfactory for most cases.A new version of the respirable impactor has recently been developed in our laboratory. This impactor approximates the ACGIH respirable curve in three steps at a flow rate of 30 liters per minute. However, unlike previous models where all of the particles larger than the three cut points designated by the three steps are collected upon one impaction plate, a separate impaction plate is now used for each of the three cut sizes. To approximate the respirable curve in three steps, the cut sizes must be 2.2, 3.5 and 5.8 microns diameter. Therefore, on each of these stages the particles collected will be the mass of particles that are larger than these three cut sizes. By determining the mass of particles collected on each of these three stages plus that on the after filter using Gravimetric techniques, some information can be obtained on the size distribution of the aerosol being sampled. Furthermore, the impaction plates of the three stages are rotated and the nozzles are placed in such a position such that a uniform deposit is obtained on each of the impaction plates. Therefore, the deposits collected are suitable for X-ray fluorescence analysis or other types of analysis where a uniform deposit is required."

Jan 1, 1988