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By Wilfredo Beltrán Zenteno

La separación de minerales a través del proceso de flotación, así como la función de los reactivos en dicho procedimiento, es de vital importancia para la producción de minerales. En este sentido, el texto señala la evaluación de los reactivos colectores y espumantes de forma rápida, realista y económica, a través de una prueba de laboratorio denominada Batch o prueba cerrada, con la finalidad de seleccionar el reactivo más adecuado en el uso industrial.

Nov 20, 1978

By D. A. Bruce

The paper describes the construction of 5 plugs to resist high water heads at depth within the South Deep Gold Mine, Randfontein, South Africa. A total of 20 segments were involved to create these plugs, which were 7.5 m long at the 58 Level and 6.25 m long at the50 Level. Emphasis is placed on the QA/QC and verification methods, which were developed and governed all phases of the work, from initial rock preparation and pregrouting through to the final grout tightening of the rock/plug interface and the surrounding rock. This paper is one in a series of papers detailing other aspects of the project, which was constructed largely between May 2001 and August 2003.

Jan 1, 2006

By Jan Krason

Introduction The South African Witwatersrand is the world's largest gold-bearing province and gold producing district. But the production capacity of the very big mines (Vaal Reef, Driefontein Cons., Western Holdings, Western Deep Levels, and others) is not as large as that of the Soviet Union's Muruntau gold mine. The Muruntau gold-bearing ore body was discovered in 1956-57, and has been in operation since that time. In the early 1970s, this mine produced 70 to 80 t/a (2.3 to 2.6 million oz per year) of gold. Within the last few years it has become the world's largest producing gold mine. Russian authors do not publish ore reserve or rate of production data. But it is very likely that the Muruntau mining complex, which involves several ore bodies, is currently producing about 143 t/a (4.6 million oz per year) of gold. The author has confirmed this by personal information from several knowledgeable Russian geologists. This amounts to one-half of

Jan 11, 1984

By Swapan Bhattacharya

United States federal and state regulatory authorities require underground mine operators to adopt adequate measures to minimize material damage to the surface caused by nine subsidence. This paper presents an approach to define and determine the extent of material damage due to subsidence from underground coal mining. The basic steps involved in the development of adequate criteria have been enumerated together with the approaches and methodologies used.

Jan 1, 1984

By V. A. Chanturiya

The state-of-the-art of mineral mining and metallurgy industry in Russia is characterized by high demand of nonferrous, rare, rare earth metals, and highgrade coal, on the one hand, and by involvement of natural and technogenic minerals with low content of valuable components, fine (nearly emulsion) dissemination of valuable components and close physicochemical and process properties. This calls for high-productive and ecology-friendly technologies for more efficient mineral beneficiation based on intensification of operating and new methods to extract valuable components from rebellious ore and technogenic minerals, relying on the last achievements of basic sciences, combination of dressing and chemico-metallurgical processes and using advanced pyro- and hydrometallurgical technologies. The transition to a new strategy of processing is only possible based on the new technological–mineralogical appraisal of a mineral raw material. Actually, the process mineralogy has a stock of modern high-resolution physical methods for analyzing composition, structure and properties of geomaterials, inclusive of micro- and nano-levels: - Identification of micro- and nano-size noble metals, and natural and induced formations on mineral surface; - Experimental validation of structural phase and chemical transformation of minerals under different energy input; - Justification of choice and mechanism of interaction between flotation agents and noble metals with complex material constitution; - Analysis of structural, phase and chemical transformations of sulfides and rocks under leaching. Thus, process mineralogy is an informational background for a unified theoretical approach to scientific justification of flowsheets of efficient mineral processing. The article gives a brief review of practices that have found application and proved to be of high economic efficiency. Such practices are: X-ray radiometry and photometry separation (Uchalinsky and Gaisky Mining and Processing Integrated Works of ALROSA); selective disintegration (equipment engineered by Mekhanobr-Tekhnika and IPKON RAS); process selectivity enhancement (IPKON RAS, Central Research Institute for Geological Exploration of Nonferrous and Noble Metals, Chinakal Institute of Mining, Siberian Branch RAS, etc.); bacterial gold leaching (Olimpiada MPIW, technologies developed the Central Research Institute for Geological Exploration of Nonferrous and Noble Metals, Nezhdaninsky deposit projects, etc.); combination processing at a mining and metallurgy plant (Norilsk Mining and Metallurgical Company, Yaregsky deposit projects and others); processing of waste: overburden, mill tailings, slag, etc. (Kovdorsky MPIW, Svyatogor JSC, Ural Mining and Metallurgical Company, plants designed by the Central Research Institute for Geological Exploration of Nonferrous and Noble Metals, Mining Institute of Kola Science Center RAS, Research Institute for Chemical Technologies); water conditioning in mineral dressing circuits (ALROSA, equipment by IPKON, etc.); utilization of process water (ALROSA, Ural Mining and Metallurgical Company, Severalmaz JSC and others). Thus, Russia this time has the academic and engineering background for development of efficient energy-saving technologies for comprehensive advanced processing in accordance with the world’s standards, or even higher in terms of a number of the technologies, which has continually been highlighted by participants of recent international congresses on mineral processing.

Jan 1, 2018

By W. G. Prast

Investments in fuel minerals and non-fuel minerals by petroleum companies are not a new phenomena. During the past 25 years, oil firms have entered mining via the acquisition route as well as by the direct development of grassroots mines. In the early 1980s, the "merger mania" in the natural resource industries came to a head. Oil company takeovers of mining firms, as well as other mergers between oil producers, captured headlines repeatedly, and speculation ran wild as to who would next acquire whom. Table 1 summarizes leading mining company mergers in the past two decades. There are some special features to the latest round of minerals investments undertaken by oil companies. First, direct takeovers of mining companies have become the preferred means of entry into minerals, with entry from scratch being relegated to the sidelines. This was not always the case. While there are instances of oil firms buying coal and copper companies dating back to the 1950s and 1960s, most of the early minerals work by petroleum firms was from internally generated projects. When the oil companies first became involved in uranium, for example, the uranium mining industry was in its infancy. There was not much market structure to buy, and it was relatively easy for everyone to get into uranium on the ground floor.

Jan 1, 1983

By B. Nemutudi, X. Zhang, B. McFadzean, P. E. Ngoepe, P. P. Mkhonto, S. Pikinini

The comparison study on adsorption of potassium normal butyl xanthate (PNBX) and sodium (nbutyl) dithiocarbamate (SNBDTC) on sperrylite mineral forms a basis in understanding the floatability improvement and paves a way for the design of collectors that may impact on a wide range of arsenide minerals. This study used a computational density functional theory (DFT) and experimental microcalorimetry approach to determine the adsorption energies of PNBX and SNBDTC collectors onto a sperrylite mineral surface. From a computational aspect, we considered the most stable surface plane of (100) surface, which had been found to give the lowest surface energy, compared to the other surface planes. It was observed that the PNBX and SNBDTC preferred to bridge on the As and Pt atoms through the S atoms. These findings showed that the collector adsorbed on the surface through both Pt and As atoms and indicated that the As atoms were significantly active in the adsorptions. We found that the adsorption energies were in the order: SNBDTC (–278.38 kJ/mol) > PNBX (–270.92 kJ/mol), indicating that the dithiocarbamate had stronger exothermic adsorption than the xanthate. From the microcalorimetry test it was also found that the SNBDTC was more exothermic than the PNBX and the adsorption energies were: SNBDTC (–473.50 kJ/mol) > PNBX (–331.13 kJ/mol). These results showed that the nitrogen atom in the SNBDTC collector had a great influence on the adsorption strength of the collector on the mineral surface. This is due to the electron deposition behaviour of nitrogen atoms compared to the electron withdrawing character of oxygen and as such the SNBDTC showed better collecting ability than the PNBX. These results paved the way for the design of collectors for sperrylite and other arsenide minerals and suggested that nitrogen in a collector may significantly improve the ability of the collector for improved recovery. Keywords: Computational modelling, microcalorimetry, SNBDTC and PNBX collectors, adsorption energies

Jan 1, 2020

By L B. Sukla, V N. Misra

Microbial desulfurisation of coal has significant advantages over physicochemical desulfurisation processes since the former process selectively removes the inorganic sulfur compounds and heavy metals without significant carbon loss. The purpose of this study was to improve the desulfurisation yield of a coal sample from northeastern coalfields, Assam, India using microbial technique. The coal sample contained 2.13 per cent of total sulfur and 2.59 per cent of ash. Stirred tank reactors of 40 L capacity were operated in batch mode. Initially, the reactor was fed with 40 L of slurry containing ten per cent (w/v) coal, ten per cent (v/v) inoculum of mixed culture of mesophilic acidophiles, native to coal itself and the requisite amounts of constituents for 9K medium without added ferrous sulfate. The percolate of the reactor was then used to seed the medium for the next experiment. The purpose was to obtain a better adapted and more active biomass which would give a better desulfurisation yield for coal. Further studies were conducted in the bioreactor, fed with 40 L of slurry containing ten per cent (w/v) pulp density of coal, ten per cent inoculum (derived from previous studies) and the medium, supplemented with ferrous sulfate. Results showed an increased total desulfurisation yield of 43 per cent in the latter treatment in comparison to the previous one, where the desulfurisation yield was only 23 per cent. The findings also demonstrated the convenience of using inocula derived from coal, where 50 - 60 per cent of pyritic sulfur was removed, while chemical desulfurisation is of little significance with the majority of coal types. The ash content was also reduced to 1.74 per cent as the low pH of the process caused dissolution of a number of common minerals present in the coal.

Jan 1, 2004

By James E. Breland

Society's growing concern over the number of deaths and serious injuries occurring in coal mines, coupled with a growing sentiment to develop and promulgate improved mandatory health or safety standards, was no doubt the basis for passage by Congress of the Federal Coal Mine Health and Safety Act of 1969, being Public Law 91-173 approved December 30, 1969. Even prior to passage of the Act, strong reaction was quick to arise concerning the effect of such legislation upon the coal mining industry. Initial response varied from mild forms of criticism to' the expressed fear of complete suspension of operations and mine closings. Primarily responsible for these early forms of skepticism were speculative or fanciful cost estimates which led operators to contemplate a less than prosperous existence. However, in spite of this unfavorable outlook, the majority of the operators have faced up to the situation and have been striving to comply with the Act and the regulations issued thereunder. While encouraging strides have been made toward implementation of the Act, it must be recognized that noticeable results have been attained only through many months of determined effort and, as anticipated, at quite heavy expense to the operator.

Jan 1, 1973

By Mark G. Lafontaine

Underground 802.11 wireless communications has become widely adopted for automation and communication purposes but maximizing the wireless signal presents many obstacles given the harsh environment as well as the presence of materials and conditions that can reduce signal propagation. Changes in elevations and curvatures in ramp to drift transitions also affect the wireless signal. Based on the requirements of wireless applications such as voice, data, or location tracking, the wireless site survey is the key tool for measuring and predicting signal strength and signal-to-noise ratio. These readings help determine the maximum distance between access points in order to sustain an overlapping wireless signal where required. This paper describes the methodology and tools used for measuring 802.11 wireless signal strength in an underground mine environment in Northern Ontario. The physical characteristics of the mine and the actual recorded wireless signal data will be presented in order for the audience to gain an understanding of the factors that affect signal throughput. Antenna selection used for the site survey will also be discussed as it played a key role in propagating the wireless signal.

May 1, 2013

By Katarina Theander, Robert J. Pugh

The generation of froth with a critical degree of stability and height is an important aspect of the froth flotation. In this paper we have studied the synergism and anti-synergism in frothing behaviour in a mixed flotation collector/frother mixture (a model fatty acid; sodium oleate and a model frother; nonionic (polyethyleneoxide alkyl C14E6). Values of the collector / frother molecular interaction parameters (the ß-parameters) were determined from the surface tension data using regular solution theory. The frothing characteristics of the system were evaluated using a glass column equipped with a series of conductivity electrodes, which enabled the water content of the froth to be determined. From these measurements, the dynamic frothability and static froth stability were determined. It was concluded that the synergism/anti-synergism in frothability was depended on the molecular composition of the surfactant system, the diffusion of monomer to the thin film interface and on the breakdown of the mixed nonionic/anionic micelles.

Jan 1, 2003

By Edward W. Parsons

The explosive-expansion center-hole anchor was designed and developed for the specific purpose of use as a component of an instrument system that measures differential ground movement within a small drill hole in rock. Such anchors should have an unobstructed center hole, should be installed without a twisting action which could tangle connecting wires, and should be capable of being installed at depths in excess of 100 feet. The anchor has a thick-walled center tube and a thin-walled outer tube. Low-energy detonating cord, wrapped around the center tube and detonated with a mild end primer, expands the outer tube to produce anchorage. The explosive-expansion center-hole anchor can be installed easily in drill holes of any inclination but cannot be installed under water. Centering of the anchor is critical with regard to its subsequent holding power. The anchor is safe to make and handle.

Jan 1, 1965

By J. G. Mitton

El uso de los flowmeters de área variable en la industria petrolera y química han simplificado algunos problemas como la alimentación exacta de productos químicos al flujo del sistema. En este sentido, el texto señala la utilidad de su empleo en la industria de flotación, así como la tardanza de su adaptación al sistema. El método de los flowmeters se adapta fácilmente a la alimentaciones de radioactivos donde el esquema es idóneo para un mineral complejo que contiene varios metales. En el caso que el mineral contiene dos metales básicos, se requiere de una mezcla intrincada de depresores para obtener una flotación selectiva o en bulk y si contiene tres metales básicos, los depresores y modificadores aumentan en número y puntos de alimentación. En 1957, como parte sus experimentaciones, la Cerro de Pasco Corporation utiilizó los flowmeters en la planta piloto de 50 toneladas cortas secas por día. Sin embargo, dicho plan presentó inconvenientes como las fallas en la correcta alimentación, errores en la calibración del alimentador de discos, órdenes a los reactivistas o derrame de radioactivos, ente otros. De otro lado, las ventajas que ofrece dicha operación está en la determinación del control de reactivos, el cual está bajo cargo de un supervisor, así como el costo de instalación se reduce a 50% en comparación con el sistema convencional de discos.

Jul 20, 1960

By D. J. Tooker

For the next few minutes, I will be discussing a product and category that many people laughed at for years. The product is cat box filiers or commonly referred to by the brand name KITTY LITTER. This product was introduced in 1947 by Ed Lowe using the name KITTY LITTER. From 1947 to 1964 the product was sold mainly through pet shops. Starting in 1964, the grocery trade began to carry cat litters. From that point, the cate gory began a solid growth trend. Particularly in the '7O's, cat litter has experienced the same kind of explosive growth that has characterized the entire pet market. For example, in the twelve months ending 9/21/79, cat litter unit volume grew by 15% versus the previous twelve months. The basis for this explosive growth is easy to comprehend. The cat population itself is rapidly expanding, reflecting the changing life- styles of Americans. As famiiies grow smaller, there is room for a pet. As apartment and con dominim living shrinks living space, a cat fills the human need for animal companionship more efficiently. Table I illustrates current cat litter market factors and projects major trends into the future to conclude that the cat litter market will equal $205MM in 1985. With this dynamic growth defined, it was imperative that a company such as Lowe's that was totally devoted to the commodity-priced products, evaluate the opportunities for added- value product differentiation. This process was started approximately four years ago with a search for new cat litter products and other new product opportunities.

Jan 1, 1980

By Ping Long, Jian Wu, Yaochun Yao

Atomic force microscope (AFM) is widely used for determining of surface performance of materials with smoother surface. In this research, atomic force microscope was used in morphology determination of powder material. Samples were dispersed in aqueous system by ultrasound wave and prepared on mica sheet. Multiple mappings of different powder samples, such as sintered products of ferrous oxalate, ferrous oxalate with lamella structure, lithium carbonate, boron powder, ferric oxide and zinc oxide, were investigated and analyzed in detail. Results showed as follow: ferrous oxalate sintered in different processes and conditions presented different morphology characteristics both in shape and size. Ferrous oxalate obtained from special process presented two-dimension lamella structure and self-assembly phenomenon. The shape and size of lithium carbonate particles were uniform. Defects of mappings on boron powder, ferric oxide and zinc oxide reflected problems of the preparation process before scanning. Determination experiences of powder material in AFM technology could be obtained.

Mar 1, 2017

By H. Majima

In spite of the importance of the presence of pyrite in the flotation of sulphide ores, not many studies have been made from the electrochemical point of view. It is generally recognized that the oxidation of sulphide minerals is one of the most Important factors among those which affect the floatability of sulphide minerals. The concept that the presence of oxygen is essential to the flotation of sulphide minerals is supported by numerous experimental results (1). The presence of oxygen in sulphide minerals- aqueous solution systems would affect the electrochemical behaviour of sulphide minerals and subsequently lead to more complicated reactions on the surface of sulphides. Actually some of the phenomena observed in sulphide flotation are deemed to be more appropriately explained from the electrochemical point of view. The author and co-workers have studied extensively the electrode reactions of pyrite and its significance in sulphide flotation. The results have been partly published elsewhere (2-7). In this paper, the author discusses the electrochemical nature of pyrite, and the three different phenomena observed in pyrite flotation: (1) Xanthate¬dixanthogen system on pyrite, (2) Flotation of complex sulphide ores containing pyrite and (3) Depressive mechanisms of pyrite with cyanide. The phenomenon which has been known as an iron contamination effect due to steel grinding media on sulphide flotation is also explained from the electrochemical aspect. However, this problem is not directly concerned with pyrite, and it will be discussed elsewhere (8).

Jan 1, 1971

By G. W. Jones

"INTRODUCTION In a previous reports results were given of a manhole investigation carried out over a period from June,- 1929, to July, 1930, in cooperation with the Edison Electric Illuminating Co. of Boston, Mass., to determine the general hazards of combustible gases and vapors in manholes and other underground openings owned by this company. Considerable time was spent in this initial investigation in developing a suitable detector for determining the range of explosibility of the gases found in manholes. About 17,000 tests have been made with the detector since the investigation was started and its utility has been verified and its accuracy checked, by having complete analyses made of such samples that showed combustibles present equal to or above 25 per cent of the lower explosive limit, and those found deficient in oxygen.The initial investigation made in 1929 and 1930 demonstrated that the detection, control, and elimination of combustible hazards in manholes can best be obtained by a close cooperation of the interested parties through a systematic and continuous inspection of manholes, under proper supervision.COOPERATIVE INVESTIGATI0N DURING 1931The investigation carried out during the year 1931 has been along lines similar to that conducted during 1929 and 1930. In the present investigation the Edison Electric Illuminating Cc. of Boston and the Boston Consolidated Gas Co., have cooperated with the Bureau of lanes. The Boston Consolidated Gas Co. serves a major part of the territory under discussion with gas, but the tests covered the Edison territory irrespective of the gam company furnishing manufactured gas. A test crew consisting of two men, one an employee of the Consolidated Gas Co. and one an employee of the Edison Electric Illuminating Co., has been continuously employed during the year in the testing of games in manholes served by the Edison system. The test crew was under the direct supervision of John Campbell, superintendent of the special service department of the Edison Electric Illuminating Co., and F. M. Goodwin vice president of the Consolidated Gas Co.As in the previous investigation, all manhole tests were given test numbers. The test data sheets on which the information regarding the tests were recorded were prepared in triplicate, one copy going to the Edison Company, one going to the Gas company, and the third to the Bureau of Mines at Pittsburgh. These test data sheets were then filed (1) according to the town, (2) the street location, and (3) the manhole number; in this way a complete record pf each manhole tested was immediately available. A specimen test sheet is given below."

Sep 1, 1932

By Mishark Nnabuchi

A heterojunction of PbS - CuS thin film has been grown on glass slides by SGT. The films were annealed for 1hr at temperature of 373K and 423K respectively. The optical properties were characterized using a UNICO UV - 2102 PC Spectrophotometer at normal incidence of light in the wavelength range of 200 - 1000nm. The minimum percentage transmittance was observed to be 34% for sample A and 25% for sample B within the same optical region. The band gap energy was determined from the spectra to be 2.05eV for sample A and 1.85eV for sample B which gave a band shift of 0.20eV. It can thus be concluded that the optical properties of the films within the VIS - UV - NIR can find application in solar thermal technology, particularly as antireflection coating, window materials and as good materials for selective solar cell fabrication.

Jan 1, 2010

By A. Shakoor, T. P. Gautam

The long-term slaking behavior of clay-bearing rocks in the field can be quite different than the short-term slaking behavior in the laboratory. To assess this difference, 12 replicate samples of each of 20 clay-bearing rocks, including 5 claystones, 5 mudstones, 5 siltstones, and 5 shales, were exposed to natural climatic conditions for 12 months. After each month of exposure, one replicate sample of each rock was removed from natural exposure and its grain size distribution was determined. Disintegration ratio (DR), defined as the ratio of the area under the grain size distribution curve of the slaked material for a given rock to the total area encompassing all grain size distribution curves of the tested samples, was used to quantify the amount of disintegration under natural climatic conditions. DR values of naturally exposed samples were then compared with the corresponding values of second-cycle slake durability index (Id2) determined in the laboratory. The relationship between Id2 and DR after, 1 month of exposure, exhibits an R2 value of 0.65 but the relationship deteriorates when DR values for 6 and 12 months of exposure are used, with R2 values of 0.63 and 0.25, respectively. However, when DR values for laboratory samples, computed from grain size distributions of slaked material after second cycle, are compared with DR values of naturally exposed samples for the three periods of exposure, the relationship improves with the corresponding R2 values being 0.61, 0.71, and 0.41. These results suggest that DR may be a better parameter for assessing the long-term disintegration behavior of clay-bearing rocks than Id2.

Jan 1, 2015

By M. A. D. Azevedo

The effect of pulping reagents on the flotation de-inking of laser printed wastepaper was investigated with regard to the removal efficiency of toner and mineral filler particles for different pH values. These results show that caustic pulping causes the toner to be released from the fibers at larger particles sizes. On the other hand, acid pulping not only causes the toner to be released at smaller particles sizes but also increases the concurrent flotation removal of mineral filler particles. It was experimentally observed that the froth generation and stability during flotation were improved for acidic pH values.

Jan 1, 1997