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By Z. Xu, Z. Li

Colloidal interactions play a critical role in mineral processing, including grinding, physical separation (particularly flotation), dewatering, and tailings management. Despite great energy input in comminution to liberate valuables from gangues, heterocoagulation between valuables and gangues would prevent the separation of valuables from gangues. On the other hand, selective coagulation/flocculation to increase the size of desired fine particles could enhance physical separation and dewatering, while dispersion is needed for fine grinding. To control the state of colloidal dispersions by creating favorable conditions, it is of paramount importance to study colloidal interactions in a relevant system and understand underlying mechanisms. This review summarizes recent advances in developing the-state-of-the-art techniques and novel methods of measuring colloidal forces, including atomic force microscope, surface force apparatus, zeta potential distribution measurement, quartz crystal microbalance with dissipation, and our recently developed integrated dynamic force apparatus. The basic principle of each technique was introduced first, followed by a summary of critical information derived for the relevant mineral processing systems. Finally, the pros and cons of each technique were discussed to emphasize the use of complementary techniques that assist in solving fundamental problems in mineral processing.

By Bror Nyman

Wide settlers are a way to decrease the linear velocities of advancing liquid phases. It has, however, been found unnecessary to risk a proper settler performance by building shallow settlers in order to avoid a so-called interface turbulence due to a too big difference between the linear velocities of the organic and the aqueous phase. This conclusion has been reached from tests using a large transparent settler model, where the behaviour of a clean interface between two advancing liquids has been investigated. Also in a more realistic case, making an organic in aqueous or an aqueous in organic dispersion to move between the liquid phases, no obstacle has been found to use a somewhat more deep and correspondingly ore slowly t10wing aqueous phase. Based on above findings, support can be given to a new trend to build the settlers slightly deeper than what has been typical for the so-called low-profile design. In this way, it is much easier to avoid an excessive air introduction and other severe difficulties, like those caused by crud moving from one stage to another. It is further shown, how gravity can be used to slow down and distribute a dispersion being fed into a settler of a VSF unit. Entrainment levels have been found to be reduced by a careful design of primary dispersion distributors and picket fences of the settler. Finally, it is demonstrated, how outlets from the side of the settler can be used to simplity interstage pumping and to decrease the rotation speed of any pumping device.

Jan 1, 1996

By Barry Hunsaker

I cannot help but be reminded, as I stand here today, of my boyhood years and heritage, both of which are inextricably tied to this very valley and are, in a: bay, apropos of the theme of this Keynote Session. I remember the scarcity of people. For example, 48, 000 in Phoenix and 436, 000 in the State in 1930 and 65,000 in Phoenix and 499, 000 in the State in 1940. Today Phoenix boasts a population of over 500, 000 and the State a population of 1, 500,000. I remember the' lack of facilities, goods and services, including gas and electric power. I recall stories of my grandfather who had the freighting or teaming contract to haul all the supplies and generating equipment, by wagon mind you, up the old Apache Trail to Roosevelt Dam. . .a three day trip from the nearest railhead which, by the way, was not Phoenix, for it did not merit a railhead on those days, but the village of Maricopa approximately 25 miles south of Phoenix. I remember chopping firewood, heating wash water on an open fire in a No. 3 wash tub at the rear of the house and doing my school homework by the light of a kerosene lamp just 25 to 35 years ago within what is now a large metropolitan area

Jan 1, 1965

By Yoshinori Shimada, Oleg Kotiaev, Hiroaki Sakamoto, Toshihiro Asakura, Naotoshi Yasuda, Norikazu Misaki, Masahiro Shinoda

"To ensure that trains run safely, the performance of railway civil engineering structures is checked by periodic inspections. General inspection method has merits and demerits, but none of them offers the combination of high accuracy and quick inspection. In an effort to resolve this problem, West Japan Railway Company, the Institute for Laser Technology and the Railway Technical Research Institute jointly developed a remote laser sensing system as an alternative to the impact acoustics method for detecting defective concrete elements in tunnel linings. The proposed remote laser sensing system has two lasers, one to apply an impact to the concrete surface and the other to measure the vibration of the concrete generated by the impact laser. The impact laser is a high-energy pulse laser that induces vibration in the concrete. The detection laser has a signal beam and a reference beam. The signal beam reflects on the concrete surface and goes into the dynamic hologram crystal. The reference beam diffracts in the dynamic hologram and enters the detection sensor with the signal beam. The vibration of the concrete surface can be measured to detect the movement of an interference pattern. A prototype of the remote laser sensing system was developed as shown in Figure1. A vibration and acoustic insulators are equipped to remove a noise generated from a maintenance car or electric generator in this system. The proposed laser remote sensing system and the detection algorithm were verified with the help of field test conducted in a tunnel on the Shinkansen. An impact test using hammering was applied to obtain the accurate response acceleration on the surface of the concrete before application of the proposed method. In this test, the result obtained from the proposed method has good agreement with that obtained from the impact test by hammering. Consequently, it is verified that the proposed method can be used as an alternative to the standard impact acoustics method."

Jan 1, 2016

By Tim Langmaid, Steve Skelhorn, Stephanie Robillard, Allen Mitchell

"The Port Mann Main Water Supply Tunnel project provides a critical water main crossing of the Fraser River for the owner, Greater Vancouver Water District (Metro Vancouver). The project consists of two 60-metre-deep slurry panel shafts and a 1-kilometre-long, 3.5-metre excavated diameter tunnel located near Vancouver, British Columbia, Canada. The initial tunnel lining is a precast concrete steel fiber reinforced gasketed segmental lining. The final lining is a 2.1-metre-diameter welded steel pipe. This paper describes the challenges encountered during tunnel construction and the solutions implemented. Key challenges include earth pressure balance tunnelling at up to 6 bar pressure—the highest to date in Canada—a water-crossing without surface access for the majority of the tunnel drive, ground freezing from a river platform for a critical TBM intervention, and boring through cobbles and boulders in dense glacial till. INTRODUCTION Metro Vancouver supplies drinking water to 18 municipalities, one electoral district and one treaty first nation, serving a population of more than 2.4 million residents. Water is collected in three mountainous watersheds to the north of the Greater Vancouver area, in southwestern British Columbia, Canada. To supply the growing demands of Metro Vancouver’s customers, treated water must be conveyed across two significant water bodies: the Burrard Inlet and the Fraser River. The existing Port Mann water main is one of several key links between the watersheds north of Vancouver and the municipalities south of the Fraser River. The Port Mann Main Water Supply Tunnel (PMMWST) is the first of a series of upgrades, to increase capacity, enhance scour protection, and improve seismic resilience. The new tunnel is 3.5 metres (11.5 ft) in diameter and 1 kilometre (0.6 mi) long. When completed, it will contain a new 2.1 metre (7 ft) diameter steel water main that will help ensure the continued, reliable delivery of drinking water to these municipalities, and will more than double the capacity of the existing 1.2 metre diameter main."

Jan 1, 2016

By William F. Riggs

Inspiration Consolidated Copper Company, located in a semi-arid climate in Arizona, continually struggles with a water problem. This applies to quality as well as quantity. When the EPA considered installing a new centralized sewage plant to handle the combined waste from the municipalities of Globe and Miami, Arizona, they automatically assumed that He could use the sewage effluent for process water in flotation. The treatment plant was to be a tertiary system producing 1600 gpm of sewage effluent. Inspiration decided that this could possibly be a source of additional process water. It was decided to test sewage effluent from Miami Treatment Plant at the rate of 400 gpm since it was only a primary treatment plant. The 400 gpm was combined with the 5000 gpm of process water going to the Concentrator. After one week the results were disastrous. The recovery and final grade had each dropped approximately 5%. With the results from this brief run, it was concluded that sewage effluent from a primary treatment plant could not be used. Research was then brought into the problem to begin an evaluation of sewage effluent in flotation.

Jan 1, 1977

By Y. Lv, H. Ye, D. Du

Electrolytic manganese residue (EMR) is a kind of industrial solid waste with high silicon content that contains harmful metal elements such as chromium (Cr), copper (Cu), lead (Pb), cadmium (Cd), nickel (Ni) and cobalt (Co). Developing a highly effective and environmentally friendly process to treat EMR is important, both for the reutilization of metal resources and for environmental sustainability. In this study, the bioleaching of available silicon from EMR using silicate bacteria is investigated, with flask experiments conducted to optimize the parameters in the bioleaching system. For metal ions, the concentrations of manganese (Mn), Co, Ni and Pb in solution were measured to determine the environmental safety effects before and after bioleaching. The results show that the bioleaching rates of available silicon in the slag were mainly affected by the temperature, pH and pulp density. Under the optimal conditions of temperature of 30 °C, pH of 7.0, pulp density of 5 percent, shake flask rotational speed of approximately 210 rpm, particle size of approximately 0.150 mm and leaching time of 16 d, the concentrations of available silicon in the bioleaching system rose to approximately 110 to 140 mg/L. The metals remaining in the residues were mainly bonded in stable fractions, with concentrations lower in the leachate after bioleaching. This study demonstrates that silicate bacteria can be used to increase the contents of available silicon from EMR, and that bioleaching technology can realize the harmless resource utilization of EMR.

By C. O. Petter

This paper, in its first part, compares the profile and economic weight in the extraction of industrial minerals and aggregates to the so called conventional mining activities (metals, coal, gas and oil extraction) in Brazil. In its second part, a descriptive analysis of the present situation of the education in Brazil is made, emphasizing the graduation and post-graduation formation especially in engineering. The curricular structure of the schools that prepare the mining workforce is discussed and the presence of specific subjects in industrial minerals is evaluated. Finally, considerations are made on the actions being taken in the main universities and companies, aiming to improve the formation of the specialized workforce. The Brazilian mining production, comparing 2010 to 2011 showed an expansion of more than 3% (IBGE, 2012). Not bad, but nothing to do with the 13% growth between 2010 and 2009 (influenced by a recovery effect from the 2008 commodities? nightmare). The commodities that had a rising behavior were titanium, gypsum, nickel, graphite, bauxite, phosphate, chrome and chrysotile. All of them were eclipsed by the impressive growth of iron ore production. Some decreases could be noticed, eg. in zinc, kaolin, magnesite and salt production (DNPM, 2012). In fact, the mining activities followed the positive growth of the country these last 5 years. The commercial balance (exports against imports) was not spectacular (positive in US$ 30 billion in 2010). It is important to notice that the mineral commodities balance was US$ 35 billion, representing 27.4% of the total exports and 15.6% of the total imports of Brazil (DNPM, 2012). In this positive environment, the workforce in Brazil showed progress in number of formal jobs and average revenues.

Feb 23, 2014

By Paul W. Johnson

Chemical mining is the in situ extraction of metals from ores located within the confines of a mine (broken or fractured ore, stope fill, caved material, ores in permeable zones) or in dumps, prepared ore heaps, slag heaps, and tailing ponds on the surface. These materials represent an enormous, untapped, potential source of all types of metals. The field of chemical mining, now in its infancy, encompasses the preparation of ore for subsequent in-place leaching, the flow of solutions and ionic species through rock masses and within rock pores, the leaching of minerals with inexpensive and regenerable lixiviants under prevailing conditions of the in-place environment, the generation and regeneration of such solutions, and the recovery of metals or metal compounds from the metal-bearing liquors. It is not inconceivable that eventually our ore reserves will consist largely of low-grade, refractory, and inaccessible new deposits and low-grade zones near previously worked deposits, caved and gob-filled stopes, waste dumps, tailing ponds, and slag-heaps. Chemical mining promises economic recovery from these types of deposits. Before it can come of age, however, a much better understanding is needed concerning its chemical and physical aspects.

Jan 1, 1967

By R. Raitani

Five kaolin crudes from the state of Georgia in the U.S. were investigated for processability with chemically enhanced magnetic separation (CEMS) technologies developed by Cytec. The technologies used magnetic reagent alone or in conjunction with specialty chemicals to selectively agglomerate and magnetize the desired minerals (impurities) to be removed by the conventional magnetic separation equipment. All crudes indicated treatability using CEMS. Results indicated that CEMS technology could be applied to different kaolin crudes to obtain a product with titanium impurities less than 0.6% TiO2 from individual crudes. The features and benefits of the technologies were also reviewed.

Feb 1, 2012

By R. R. Klimpel

This paper describes four new families of flotation products which are currently being introduced at the industrial level. A brief summary of the chemical basis behind each product family will be given. This is then followed by a selection of flotation examples which illustrate the more important use characteristics that have been observed to date. It is becoming more apparent with further testing that these four new product families can offer both technical and economic advantages to the industrial flotation process operator.

Jan 1, 1992

By M. Guzman, S. B. Thais, M. F. Obispo, M. R. Arribasplata

One of the greatest environmental issues related to the development of the mining activity is the generation of Acid Mine Drainage (AMD). Many methods have been developed for AMD treatment, being wetlands a good option for heavy metal removal. In this sense, the implementation of artificial wetlands for the treatment of mining effluents would seem to be an environmentally friendly alternative. In this paper, we present the results on the elimination of heavy metals (Cu, Zn, Pb and Fe) using two Peruvian native species such as Schoenoplectus californicus (C.A. Mey.) and Phragmites australis (Cav.) Trin. Ex Steud. The results show that Schoenoplectus californicus preferentially removes copper (82 and 90%), lead (88 and 92%) and iron (28 and 69%), whereas Phragmites australis removes copper (68 and 87%) and zinc (53 and 95%). Likewise, it is observed that the Schoenoplectus californicus mainly retains the ions in its root, copper (89%), zinc (84%) and iron (76%). While the Phragmites australis accumulates iron (62%) and copper (74%) in the steam and root part respectively

Mar 2, 2022

By C. Iglesias

Innovation in the tilemaking ceramic industry is stressing properties like powder flowability, ability to toughen green tiles, so turning technological requirements of ball clays ever stricter in terms of plasticity, dispersion in water, rheological behavior, workability in the green state, refractoriness and firing colour. Technological performance of ball clays was improved by taking as benchmark the highest quality raw materials on the market. The mineralogy, plasticity, methylene blue index and ceramic response of the Patagonian ball clays are analogous to those of European clays, but improvement is needed to approach the highest quality materials. On this basis, the Frente A, Super, Puma, and Lote 8 deposits were selected and their characteristics enhanced by additions of highly plastic and white-firing corrective clays targeted on the benchmark. Porcelain stoneware formulations, containing improved ball clay mixes, were experimented at both laboratory and industrial scale. The improved ball clays behave like the best raw materials currently used, although modest changes occur in the mechanical properties, water absorption and whiteness of the fired products.

Jan 1, 2010

By A. W. Khair

This paper deals with the evaluation of the interaction between rock and the cutting tool, and with methods for determination of workability, and abrasivity of rock. A description of instrumentation is included along with research on the wearing process of bit tips and pick consumption. Analyses of bit rotation, evaluation of cutting, normal forces and energy consumption is presented. Finally influence of the basic water jet parameters and water jet assistance on the cutting process of hard and abrasive sandstone is discussed.

Jan 1, 1995

By J. B. Griffiths

Clearly there is a tremendous need for assistance in Eastern Europe since most industries must undergo major restructuring. The new governments face many dilemmas, the first task being to establish an order of priorities to deal with the numerous problems at hand. Issues such as the standard of living take low priority compared with market economy and ecological problems. The concept of a Comecon market is now virtually non-existent and trade in roubles ceased from 1991. From this time onwards countries were obliged to trade using free market prices. Governments must also avoid the economic mistakes of countries such as Poland with its high devaluation and lack of economic control and, if possible, contain inflation and unemployment. The privatization of Eastern European enterprises raises considerable difficulties, particularly for large corporations, employing anywhere from 50-100,000 people, which played a major role in the national economy. Whichever method is selected, however, still has to overcome the problem of lack of capital and evaluating the national property. For example, earnings represent only a small percentage of the value of these national industries and thus cannot convert to private ownership without foreign capital investment, either direct or as joint venture capital.

Jan 1, 1992

By J. Z. Keating

There are close to two million tons of Industrial Minerals processed and sold in North America wherein the processor/marketer has no affiliation with the source mine. The largest quantity, about 800,000 tons, is barium sulfate, which is sourced in lump ore form mainly from China and India. The Alumina Trihydrate Industry sources several hundred thousand tons from various alumina refineries. Substantial quantities of bauxite, zircon, magnesite, and fluorspar arrive in North American ports each month. There are also rapidly growing quantities of offshore talcs and calcium carbonate ores being processed in U.S. plants. These feedstocks are usually quite pure, have unique properties, and enjoy bulk rail or waterborne freight economies that allow successful competition with locally sourced raw materials. With increasing restrictions on mining activities, and the increasing need for sophisticated functional minerals, the importation of minerals will continue to grow.

Jan 1, 1994

By F. A. Renninger

The mineral aggregate industry is the world's largest mining and processing endeavor, yet it is graced with little of the romance or public awareness that accompanies mention of gold, silver, iron, copper, uranium, or aluminum mining efforts. Much of this reaction is undoubtedly due to the fact that the uses to which crushed stone and sand and gravel are normally put are not fully recognized or appreciated by the general public. Few individuals ever have occasion to purchase mineral aggregates for anything other than use for decorative shrubbery beds or walkways. They may, however, buy ready-mix concrete for a new patio, bituminous concrete for a new driveway, concrete blocks, or other building materials for a new room and never realize that the primary ingredients of their purchases are either direct or indirect products of the mineral aggregate industry. The average person driving past an operating crushed stone quarry or an active sand and gravel pit rarely realizes the economic impact the industry, represented by that operation, exercises on the general economy. He is not aware, nor does he really care, that elements of the modern comfortable environment to which he has grown accustomed rely to a great extent on the products of the crushed stone and sand and gravel industries Iron and steel, glass, cement, agriculture, and highway and building construction are but a few of the major industries to whom the products of the mineral aggregate industry are basic. Without these industries or without the stone, sand, and gravel basic to them, most of the major elements of our modern day civilization would be non-existent.

Jan 1, 1968

By J. G. Groppo

Eastern U.S. oil shale contains approximately 10 to 12 gallons of oil per ton and 7 to 10 percent pyritic sulfur. Physical beneficiation of these low grade shales using froth flotation provides a high grade material which will make extraction of oil more economically attractive. The Alabama oil shale used in the present study contained 16.46 percent organic carbon and 14.5 gallons of oil per ton as determined by Fischer assay. Liberation size of the kerogen was estimated at 10 /-Lm. 'Ken-Flote' column flotation technology provided a high grade concentrate containing as much as 60 percent organic carbon, however, carbon recovery was about 60 percent. Carbon recovery was improved to 75-85 percent while maintaining concentrate grades in excess of 40 percent carbon by providing longer retention time in the column which facilitated effective bubble-particle collision and attachment.

Jan 1, 1993

Coal has traditionally been an integral part of life in Kentucky. Coal mining produces a large part of revenue for the Commonwealth of Kentucky and provides a significant number of jobs to the residents of eastern (less in western) Kentucky. Recently, however, the coal industry of Kentucky has had to endure many hardships. The Clean Air Act set forth sulfur dioxide emission standards which have severely affected much of the coal mining industry in Kentucky, because much of the coal mined in Kentucky has a high sulfur content. In this paper, the background around the effects of Clean Air Act on the coal industry is introduced. The economic and social effects of the Clean Air Act on the Kentucky coal mining are addressed.

Jan 1, 1993

By K. J. Shoop

This study investigates the use of a horizontally-baffled column (7.6 cm inside diameter by 344.2 cm high) to reduce the ash content of a high ash bituminous coal. Tests were carried out to determine how the baffled column responded to changes in feed rate, reagent dosage, and feed quality, and to compare its performance with a conventional column installation in an operating plant. In this paper, the results of this investigation will be reviewed and discussed.

Jan 1, 1997