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By Gary A. Wickham

In the zinc industry, this past decade has seen both prosperity and depression. Significant changes have occurred throughout the world in mining, smelting, refining, and marketing. This paper will review many of the industrywide changes of recent years and the potential impact for 1990s. In addition to an historical review of supply and demand are discussion of technology considerations for zinc and zinc based products, effects of geographical shifting of markets, and projections for the 1990s.

Jan 1, 1990

By Walter D. Holland

LFE Environmental performed an Industrial Hygiene survey of the Paraho Oil Shale Mining and Processing facility in Anvil Points near Rifle, Colorado, on August 6 and 7, 1975. This survey consisted of an investigation of the underground operations for diesel emission contaminants and of the above ground work areas for all inhalation contaminants other than silica dust. Samples were collected to investigate the following contaminants: respirable dust, total dust, NO2, NO, H2SO4, formaldehyde, CO2, S02 and CO. None of the determinations of contaminants in the underground operations indicate air concentrations exceeding their standards. The results for the samples collected above ground indicate only one operation where the employee's exposure exceeds the standards. It is a welding operation where the standards for total dust and lead are exceeded. Since the survey the employer has installed an exhaust ventilation system which has significantly reduced the welder's exposure.

Jan 1, 1976

By M R. Dehghan, H Mansouri, A Hakami, M A. Ebrahimi Farsangi, F Faramarzi

Today, it is accepted that rock fragmentation by blasting affects loading and hauling operations, and also directly influences on downstream processes such as crushing and grinding. In this research, the influence of rock fragmentation by blasting on the performance of three mills at Gol-e-Gohar iron ore mine No 1 was studied. Firstly, the fragmentation of conventional blast patterns in iron ore (5 × 6 m) was studied using image analysis and the performances of three mills were monitored. Then, a new blast pattern (4 × 5 m) was designed and nine blasts were carried out using this pattern. Increasing the powder factor form 1650 gr/m3 to 2480 gr/m3 by changing the blast pattern design showed that mill throughputs increase five per cent to 30 per cent for the new pattern.CITATION:Hakami, A, Mansouri, H, Ebrahimi Farsangi, M A, Dehghan, M R and Faramarzi, F, 2015. Study of the effect of blast pattern design on autogenous and semi-autogenous mill throughput at Gol-e-Gohar iron ore mine, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 315–320 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By R. Schipper

Two bench scale biochemical reactors (BCRs) were operated over a period of 3 months for the removal of uranium, radium, and selenium from mining influenced water (MIW). A BCR is an anaerobic reactor comprised of organic and inorganic substrate including woodchips, straw, sawdust, and limestone. Uranium and selenium are removed in a BCR by biological reduction of oxidized species (i.e., selenite, selenate) to less soluble forms (Pahler et al. 2007, Blumenstein et al. 2008, Rutkowski et al. 2013). It is believed that radium may be removed through absorption to the biomass in the BCR. The bench scale BCRs were constructed of 6 inch PVC columns with a top to bottom flow configuration. The bench influent water consisted of three different water ratios from two adit seeps. BCR hydraulic retention times of 24 to 36 hours were targeted during the study. Influent concentrations ranged from 19 ug/L to 1.86 mg/L for dissolved uranium, 12 ug/L to 270 ug/L for dissolved selenium, and 4.9 pCi/L to 24 pCi/L for radium 226. The average and maximum dissolved uranium removal was 93.6% and 98.5% respectively, the average and maximum dissolved selenium removal was 93.3% and 98.9% respectively, and the average and maximum radium 226 removal was 89.5% and 100% respectively.

Feb 23, 2014

By Kefton H. Teague

An article entitled "The Rule of the Geologist in the Industrial Mineral Field" by G. R. Gullet, was published in the August, 1967, issue of the Canadian Mining Journal. Mr. Gullet defined industrial minerals as follows: "Industrial minerals are largely non-metallic minerals and rocks that find value because of their physical or chemical properties." This definition is brief, but all-inclusive. Mr. Gullet continues, "They include all useful minerals and mineral commodities except those used as fuels and those from which metals are extracted. Factors in the evaluation of an industrial mineral deposit are generally as different from those used in the evaluation of a metal deposit as is the assessment of a potential oil field. The key to the successful development of an industrial mineral, deposit is more often a balance of accessibility, transport, and proximity to markets than to any natural quality advantage of the deposit itself."

Jan 1, 1972

By N. Kanari

The kinetics of oxychlorination of MgO by C12+02 was studied in the temperature range of 850 °C - 1025 °C, using thermogravimetric analysis. The effects of C12/02 ratio, gas velocity, temperature and partial pressure of reactive gases on the reaction rate were investigated. The oxychlorination process was characterized by an apparent activation energy of about 214 kJ/mol. The reaction orders with respect to C12+02, C12 and 02 at 950 °C were about 0.65, 0.98, and -0.37, respectively. Some data about oxychlorination kinetics of MgO, Cr2O3, and MgCr2O4 contained in chromite were compared. Efficiency of using oxychlorination for the removal of iron oxides contained in magnesia was demonstrated.

Jan 1, 1999

By W. A. Haley

This paper discusses how a large wheel loader should be equipped, with particular attention paid to tires and tread life, and describes the several steps that can be taken to provide favorable working conditions and reduce over-all costs. A comparison is then made of wheel loader production and costs vs those of power shovels, and the present and possible future applications of the wheel loader are outlined.

Jan 1, 1969

By C. Hsu

Underground coal gasification (UCG) is becoming more popular as the reserves of good quality, mineable coal are starting to diminish, and yet the global energy demand from coal is still increasing. The purpose of this research project was to investigate cavity formation within a coal block due to the combustion reactions in the context of UCG. The cavity plays a pivotal role in the UCG process, as it is essentially the gasification reactor. Cavity formation in an in situ gasification process using the forward combustion linking method (FCL) had been investigated, and a laboratory model was created to simulate the process. The experiment was performed by drilling a U-shaped tunnel into a coal block, which was then combusted internally with air that was fed through an injection hole. A heating element (at approximately 500°C) was used to supply the required heat for combustion at the base of the injection well. The coal blocks were analysed using micro-focus X-ray tomography. The tomography results showed that the coal tended to crack along the bedding plane after a short duration of combustion, due to either the formation of clinker or the expansion of swelling vitrinite along the horizontal tunnel. The deposit was thicker at the base of the injection well compared to the base of the production well; this may have been caused by the turbulence of the air flow and the relatively high oxygen concentration at the base of the injection well. A comparison of the results with work by Daggupati et al. (2010) showed the same trend, despite the slightly different methodology applied.

Jan 1, 2014

By X. Cao, J. J. Jonas, Wanjara. P., J. Gholipour, E. Dalgaard

The linear friction welding (LFW) behaviour of near-ß titanium alloy Ti-5Al-5V-5Mo-3Cr (Ti- 5553) was investigated. Microhardness measurements were performed in order to evaluate the mechanical properties of the welded material. The linear friction welded (LFWed) Ti-5553 was examined with optical microscopy and scanning electron microscopy (SEM) to evaluate the microstructure’s response to the thermomechanical conditions. Characterization of the welds included analysis of the microstructural features of the weld region and thermomechanically affected zone (TMAZ) in relation to the parent material.

Jan 1, 2010

By Hiroshi Tabuchi, Akihiko Takahashi

"High strength aluminum matrix composites were prepared and studied using as reinforcement newly developed nearly mono-dispersed a-alumina single crystal particles each of which has a regular polyhedral shape. The composites were formed by centrifugal casting using aluminum casting alloys (Al-Si and Al-Cu-Mg) as the matrices, followed by heat treatment. The volume fraction of the alumina particles was as high as 60%. The same matrix composites reinforced by conventional crushed fused alumina particles were similarly prepared as the reference. The bending strength and tensile strength of the Al-Cu-Mg matrix composites reinforced by the novel alumina particles of 10 µm in average diameter are as high as 1020 MPa and 560 MPa, respectively, which are higher than those of the conventional alumina composites. Furthermore, the bending strength of the novel alumina composites degraded less than that of the conventional alumina composites after thermal fatigue tests. The number of cracks in the matrix seemed to influence the thermal fatigue property because many cracks were observed in the conventional alumina composites, whereas only a few cracks were observed in the novel alumina composites. This was confirmed by SEM observation of the sample composites before and after the thermal fatigue tests.IntroductionAluminum matrix composites strengthened by dispersed reinforcements are of interest for various applications due to their improved properties, such as high specific strength and stiffness, wear resistance, etc .. A large number of investigations have been made concerning fabrication processes and properties of these composites. With regard to the fabrication processes, powder metallurgy has been well-known as a solid phase process, and recently many liquid phase processes such as a compocasting, a squeeze casting, the Lanxide process, and the Osprey process have been studied and developed.(1)"

Jan 1, 1998

By Juan Beltrán

Durante el tiempo de operación de la refinería de Ilo, el teluro ha ocasionado problemas operativos en la calidad de depósito, al contaminarlo química o físicamente. El objetivo del presente estudio fue minimizar la concentración de teluro en la solución de agua madre, producto de la lixiviación de lodo anódico, mediante el proceso de cementación de teluro con cobre. En las pruebas desarrolladas en planta se alcanzó una extracción de 24% de Te, lo que hizo posible dar mayor valor agregado a los subproductos de la refinería.

Sep 30, 2020

By R. C. Miranda

The purpose of this work is to present ?state of the art? mass balances closing strategies in ore treatment plants. It presents a brief history of difficulties and challenges ahead. The current methodology is based on usage of an expert system, which seizes and filters the plant data, analyzes situations of equipment stops and mostly instruments failures. It is still possible to internally create a strategy to check the data of an instrument failure. The system is coupled to software with a Lagrangian model of mass balance closure that receives the pre-treated data. Thus, the data goes through filtering and reconciling processes to generate a reliable mass balance of the ore treatment plant. This made possible to obtain a system that is able to tell the real productivity of a ore plant through reliable mass balances. Residence times on equipments are critical to the balance, thus, they require good logic to eliminate errors due to the characteristics of non-steady state. Among the next challenges is the inclusion of a ?soft sensor? as a replacement of an instrument required for mass balance closure.

Sep 1, 2012

By G. C. Milligan

"A regional mapping program, conducted by the Nova Scotia Department of Mines, has shown that the George River Group of pre-Middle Cambrian rocks consists of a wide range of sedimentary and volcanic rocks, intruded by syenite, granite, granodiorite and lesser amounts of gabbro and diorite. Together, these rocks support the high ground of northern Cape Breton Island. Over this large area, the metamorphic grade ranges from low to extremely high.The rocks were folded prior to emplacement of the intrusions in Middle Cambrian time, and there was also post-Mississippian disturbance and faulting, but the structural history and pattern are still only imperfectly understood.Sulphide mineralization is known at Meat Cove, Lime Hill and in a number of smaller deposits. The most Cavour-able host rocks appear to be magnesian Iimestone, or schists derived from shales. Ail known sulphide bodies have an associated halo of retrograde metamorphism; in some cases, this is extensive enough to be used as a prospecting aidA vein of nickel-bearing sulphides has recently been re-discovered in the former gold mine at Second Gold Brook-an association which appears to be unique."

Jan 1, 1971

By C. H. Sleeman

"The Iron Ore Company of Canada constructed a beneficiation complex in Sept-Iles, Quebec, to concentrate and pelletize earthy red hematite iron ores from the Knob Lake area. The plants were scheduled for initial production during the first quarter of 1973.Many problems have been experienced to date. Difficulties in controlling the process, excessive mechanical failures, design deficiencies and manpower-staffing problems have caused an extended start-up. The problems are now essentially solved and, with the completion of some additional minor modifications, it is expected that the plants will be producing premium iron ore pellets at or near rated capacity within the next immediate period."

Jan 1, 1976

By R. H. Knudsen

"In view of the chronic overcapacity problem in the world potash industry and Saskatchewan's recent emergence as a major producer, the long-term outlook for potash productive capacity and consumption is of importance and interest to both the Saskatchewan Government and the potash industry. This paper is based on a report recently published by the Saskatchewan Department of Mineral Resources on projected world potash productive capacity and consumption for the ten-year period 1970 to 1980. Potash productive capacity and consumption are estimated on a country and regional basis and projected annually to 1980. Tables and graphs are included which summarize projected capacity and consumption for the period and illustrate the impact of Saskatchewan's capacity upon the North American and world potash industries."

Jan 1, 1973

By G. Önal

Recovery of nickel and chromite from the tailings has been studied on the samples with 0.214 % Ni and 5.10 % Cr2O3 content and taken from Orhaneli Chromite Concentration Plant. Mineralogical examinations of the samples showed the existence of chromite, olivine, pyroxene, chrysotile, anti-gorite, chlorite, idingite, tremolite and calcite together with trace amounts of millerite, pentlandite, pyrite, pyrrhotite, hematite and limonite type iron oxide minerals in partially serpantinized dunite type particles. In order to recover chromite from Chromite Concentration Plant tailings Mozley Table and Knelson Separator are used and concentrates containing approximately 42% and 46% Cr2O3 are produced respectively with 40% recovery. Most of the nickel remained in the tailings. Therefore, acidic leaching tests are performed in order to dissolve nickel from these tailings. Effects of particle size, acid concentration, temperature, leaching time and solid/liquid ratio on the nickel leaching efficiency are investigated. The optimum leaching conditions are found as 250 g/L acid concentration, 1/5 solid/liquid ratio, 2 hours of leaching time and 60°C temperature, almost all nickel is dissolved at the optimum conditions and acid consumption is about 841 kg/t. Repeated leaching tests are carried out in order to have enough Ni content in the leach liquor for the further treatment of solutions. After repeated leaching tests, leach liquor contains 3 kg/m3 Ni, 48 kg/m3 Fe, 2.2 kg/m3 Si, 23 g/m3 Cr and 590 kg/m3 H2SO4. Ni is recovered from that solution by precipitating with H2S followed by HNO3 dissolution and precipitating Ni as hydroxide with 63% Ni content. Leach cakes are subjected to the gravity separation (Mozley table) to recover the remained chromite and a chromite concentrate with 47% Cr2O 3 content is produced with 53% recovery. As a result of the abovementioned tests, a conceptual process flow sheet is proposed for the treatment of these chromite concentration plant tailings.

Jan 1, 2014

By F. Burat

At the present time, methods of mining and coal preparation produce tones of coal fines. The removal of water from these fines is necessary for economical and technological reasons. Supplementary processes that utilize different physical and chemical methods have been developed to in-crease the productivity of mechanical dewatering processes. Researches have shown that chemical reagents used along with conventional systems diminish moisture and increase the capacity and the yields of the dewatering method. In this study, the parameters of the vibrating screen (incline, frequency, feeding rate and screen size), the effects of the application of additional vertical mechanical vibration and surface active reagents (CTAB, SDS, Umectante B-70 and Kerosene) were investigated. At the end of the optimization experiments, 61.0% moisture was decreased to 42.3%. By keeping optimum conditions con-stant, the experiments have been conducted to determine most effective reagent. 41.2% moisture has been obtained with 5 g/t CTAB at the normal pH of the pulp, which were 7.25. By using vibrating screen with combination of the vertical vibrating mechanism, CTAB gave the best result of 40.7% moisture. Finally, the effect of increased surface area of the screen has been investigated and de-creased the moisture level to 38.7%.

Jan 1, 2014

By Rustu S. Kalyoncu

Nonoxide ceramics with improved high-temperature properties could substitute for high-temperature alloys and reduce toe Nation's dependence on imports of Cr, Co, Ni, and Mn. To meet this objective, the Bureau of Mines conducted research to synthesize u1trafine reactive boron nitride (BN) powders BN powders were prepared at temperatures ranging from -75? to 750? C. Low-temperature reactions (-75? to 200? C) between boron halides and N compounds led to formation of e1emento-organic compounds that were thermally decomposed to u1trafine (approximately 100-to 150-A particle size) reactive BN powders. BN powders were also prepared through the reaction of a 10w-me1tinginorganic B compound (boric acid, borax) with an organic N compound (carbimide and thiocarbimide) in N2 and/or ammonia (NH3) atmospheres at temperatures between 500? and 750? C.

Jan 1, 1986

By Edward F. Nagle

Instrumentation engineers have recently devised practical methods of metering the net solids flowing in a hydraulic mixture. The solids flow rate is determined by measuring the specific gravity and the flow rate of the mixture. T e specific gravity is measured by a variation of the bubbler system. The flow measurement is made by a somewhat unorthodox orifice requiring field calibrations. The linear mixture flow signal is then multiplied by the specific gravity signal, which is directly proportional to the percentage of solids in the mixture, to produce a linear solids Slow rate signal. The computations in this system are performed by Sorteberg pneumatic relays. Having obtained this measurement, integration and automatic control of hydraulic solids flow are available. This system is useful in mining, drilling and dredging industries. It provides maintenance of the net solids flow rate and reduces power consumption. Automatic control will provide rapid stabilization of net solids flow rate and release operators from making menual adjustments. The advantages of this application are economy of operation and increased pump efficiency, This paper describes a hydraulic solids flowmeter system installed aboard a dredge. Its purpose is twofolds:- 1. 20 provide a summation of the net solids flowing 2. To make available a practical guide for the drag tender operator. (Dwg. GSD-2219)

Jan 1, 1958

By Ian Ewart, Trevor Bergfeldt, Gourab Satapathy, Ajay Patel

"Conventional electrowinning (EW) of nickel from sulfate electrolytes is complicated by several factors including the requirement for a diaphragm cell to separate the anolyte and catholyte and the need to minimize nickel mist emissions. Developed and commercialized by emewCorporation, this novel process electrowins high purity nickel cathode (99.5%) from copper refinery bleed streams using the proprietary emew vortex EW technology. The emew nickel process incorporates high flow rate in an enclosed cylindrical EW cell operating at high current densities that overcomes the challenges of conventional nickel EW and completely eliminates the risk of nickel mist emissions. The tubular cathodes are easily harvested and mitigate the effect of plating stresses inherent in nickel EW. The present paper describes the emew nickel process and its most recent application to copper refinery bleed streams at full-scale.INTRODUCTION To meet the stringent demand of customers, nickel producers are giving prime importance to production of high purity nickel cathodes. The major challenge for refineries is to improve cathode quality and appearance despite fluctuating electrolyte impurity levels. The basis of achieving good quality cathode includes the control of electrolyte impurities and consistency of specific process conditions. The commercial operation of emew nickel technology has been successfully implemented and has demonstrated the ability to produce high quality nickel cathode from refinery bleeds. This paper emphasizes the importance of upstream impurity removal to achieve the required nickel emew feed composition by evaluating the benefits of using selective precipitation as a purification scheme with the aim of improving the overall nickel recovery while ensuring suitable nickel concentration in the advanced electrolyte is achieved. Nickel electrowinning is similar to other electrowinning processes that employ insoluble metal anodes & cathodes. It requires the passage of direct current between two electrodes that are immersed in a conductive, aqueous solution of nickel salts. For the recovery of nickel from solution, the most common methods are electrowinning and hydrogen reduction. Electrowinning usually occurs from sulfate, chloride or mixed sulfate/chloride electrolytes. In sulfate electrolytes, nickel electrowinning cells are normally designed to achieve specific criteria as outlined below (Robinson & Tuppa, 2002):"

Jan 1, 2017