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"In this review, the sintering process is first described and analyzed to identify the key factors affecting the structure and quality of iron ore sinter. Under fixed sintering conditions, the granulation efficiency, nucleus stability and primary sinter melt volume and properties of the iron ore are considered to have significant influence on the sinter structure and quality. Discussion is then focused on the effects of the chemical, physical and mineralogical characteristics of the iron ore on these key factors, and the consequences for sinter quality.IntroductionSintering is the most economic and widely used agglomeration process to prepare iron ore fines for blastfurnace use. In modern blast furnaces, particularly in East Asia, iron ore sinter typically constitutes more than 70% of blast-furnace ferrous feed. High sinter quality and efficient sinter production are thus required both to withstand extreme operating conditions and maintain the productivity of modern blast furnaces. At the same time, due to the increasing depletion of high-grade iron ore resources from large deposits, iron ore producers are moving toward developing an increasing number of deposits of much smaller sizes to maintain current production levels. It is therefore imperative for iron ore producers to develop long-term strategies to maintain the quality and consistency of the iron ore fines they are producing while exploiting these smaller, complex deposits. The iron grade, gangue minerals present, overall mineralogy as well as physical characteristics of iron ore fines being mined from these different deposits vary considerably. Overall, ores now have highly complex mineralogy, are becoming more porous and friable, and contain increasing amounts of gangue minerals, which will have important implications for the sintering process and sinter quality.Blending is one of the most effective options being explored by iron ore producers to deal with multiple small complex deposits. This allows the iron ore producers to reduce the number of products and take full advantage of the unique characteristics of each individual deposit to achieve long-term product consistency while increasing production. Blending is also a common practice in sinter plants as it is almost impossible to produce from one single ore a high-performance sinter mixture with the required processing characteristics. A typical sinter mixture used in Japanese steel mills (Nakano and Okazaki, 2007; Matsumura et al., 2013) often contains five or more ores to achieve balanced sinter quality and productivity with relatively low cost of raw materials."

Jan 1, 2015

By Brian V. Roulston

Potash is Canada's leading industrial mineral in terms of value of production, with 11.1 M tonnes of muriate of potash produced in 1992 for a value in excess of $1 billion U.S. Each tonne of potash produced generates about 2 tonnes of waste salt, together with slimes and brine. The disposal of these waste products, particularly the salt and slimes which are discharged on the surface, has recently become an environmental concern. This concern is forcing companies and regulatory authorities to review disposal practices. In New Brunswick, on Canada's east coast, Potash Company of America operates a mine at which 2 M tonnes of potash ore and 0.5 M tonnes of rock salt are mined each year. The mine is situated in an environmentally sensitive area, noted for its dairy farming and salmon angling. In such an area it was recognized that the storage of waste on surface would be unacceptable, and the mine was designed around this principle. Three main waste streams - salt, slimes, and brine - must be managed as an integral part of the mining system. Around 1.5 M tonnes of fine salt tailings from the milling process and the rock salt screening operation, are sent directly to the active cut-and-fill potash stopes to be used as backfill. Slimes and excess brine from the mill are piped underground as a slurry to be discharged into one of the basin shaped stopes created by mining of the rock salt. While the slimes settle out, the clarified brine is withdrawn from part of the stope to be pumped to surface as a feedstock for the evaporator - a process which recovers the contained potash values in the brine. By designing a system which integrates the mining, processing and disposal of all product streams, and by careful production planning, it has been shown that zero effluent potash mining is possible and points the way for the industry in the future.

Jan 1, 1995

By M. Misra

It is estimated that the volume of low -level and intermediate level contaminants present in the soil at different DOE sites is of the order of several million cubic feet. The existing remediation scheme is containerization followed by burial in Land Disposal Facilities (LDF's) which is economically unattractive warranting the need to develop alternate remediation routes. One such route is the physical separation based volume reduction approach to removing a MINIMUM AMOUNT OF CLEAN SOIL with the radioactive particles, reducing the amount of material that requires disposal. The purpose of this study was to evaluate and test the feasibility of using physical beneficiation techniques for removal of contaminants from soil. The performance criterion was to recover at least 80% of the activity in 20% or less of the original contaminated soil volume. Four different radioactively contaminated (primarily uranium and plutonium) soils from DoE sites namely LANL, INEL, Fernald Plant 1 Storage Pad (ID-B) and Mound soils were tested using gravity, magnetic, gravo-magnetic, hydrocyclonic and flotation devices. The paper is divided into the two sections. The first section presents the overview of the Heavy Metals in Contaminated Soil Treatability Project conducted at the University of Nevada, Reno (UNR) describing the salient features of a state-of-the art Soil Washing Laboratory and the technology equipments used in the test program. The second section describes the soil characterization and typical volume reduction results obtained from the UNR tests. Among the physical separation processes, only flotation processes passed the performance criterion. For the LANL and INEL soils where the contamination was contained in coarse particle size, it was possible to recover more than 80% of the activity in less than 10-20% of the original volume of the soil thus rendering 80-90% of the soil "clean". For Fernald and Mound soils where contamination was of colloidal nature, flotation based processes showed encouraging results and are recommended for further studies.

Jan 1, 1995

By A. Ferreira Morgado

The sodium smectitic clays (bentonites), have more industrial applications in that class of mineral, a driving force to obtain this mineral. In Brazil, there are several occurrences of smectitic clays, unfortunately they are polycationic, with a distribution of several exchangeable cations, where the cation sodium occurs in minor quantity. In this work, the original polycationic smectitic clay was firstly proper characterized and then treated with sodium carbonate obtaining homoionic sodium smectitic clay. The rheological tests in the optimized sodium smectitic clay showed good results for drilling fluids, typical of a sodium bentonite ones.

Jan 1, 1999

By J. A. Marts

Reservoir properties including porosity and permeability distributions in longwall coal mine gobs have direct application to modeling the flow patterns and gas distributions in the gobs. Proper assessment of these distributions is required to assess gob gas hazards such as spontaneous combustion and explosive methane mixtures and to optimize gob gas venthole operation and nitrogen inertization. Determining the reservoir properties is difficult given that the gob is inaccessible and direct measurements cannot be easily taken. Several techniques have been used by previous researchers and will be discussed. This paper will present the methodology used to model the gob compaction by simulating the sequential extraction of coal. Two Western US coal mines were used for case studies. By determining volumetric strain, the porosity and permeability distributions in the gob can be calculated. The geo-mechanical model predicts an axisymmetric volumetric strain distribution with a steeper slope near the start-up room and a shallower slope near the active face.

Feb 23, 2014

By M. T. Ityokumbul

The liquid phase mixing in Western Research Centre (WRC) pilot plant flotation column with diameter of 0.76 m has been characterized using a salt tracer. The process variables studied were gas and liquid flow rates. The response of the column to a tracer pulse input was monitored at three axial and two radial locations. For all the experimental conditions investigated in the present study, radial and axial concentration gradients were not observed. It is thus concluded that the 2 tph flotation column is behaving as a well mixed tank. This finding is consistent with the observed poor recoveries of coarse fractions in the column flotation circuit. Based on the findings of this report, it is recommended that several schemes of reducing the backmixing be implemented and evaluated for their effectiveness in improving the column recoveries.

Jan 1, 1994

By David A. Newman

The Geomechanics Classification (Bieniawski, 1979) was modified for entry and roof support design in underground room-and-pillar coal mines. Adjustment multipliers were introduced to incorporate the influence of strata weatherability, high horizontal stresses, and the roof support reinforcement factor into the existing classification system. Sixty-two case histories of both standing and fallen mine roof were collected from two mines in the northern Appalachian coalfield. Twenty-seven engineering and geologic parameters were recorded for each case. A partial correlation analysis was carried out on the cases to establish which parameters have a significant impact upon the supported stand-up time of coal mine roof. Survival analysis, a statistical technique used in medical research to assess the effect of a drug or treatment on a patient's life expectancy, was conducted together with stepwise multiple regression to derive values for the adjustment multipliers. A practical example is included to illustrate the application of the modified Geomechanics Classification to underground coal mine design.

Jan 1, 1985

By N. Del Bel Belluz

Drilling underground in the Grasberg De-watering drifts has routinely hit water aquifers with high flow rates and pressures. Two types of holes are utilized; pilot-holes to probe ahead of the tunnel development to intersect aquifers ahead of the face; and de-watering holes to de-water rock formations that will drain water from the Grasberg pit and allow tunnel development to proceed safely. Recently, rates of 1050 psi static pressure have been recorded with flows from a NQ hole measured at 1350 gpm (US). The water flows can be slightly acidic, necessitating the use of stainless steel collar gear to resist corrosion. These rates were anticipated and contingencies were planned early to deal with these conditions. The collar gear is used to control water flows whereby the water is treated as an important resource. As a result, pm has established procedures to maintain safety of the drill crews, enable coring of the rock and to maintain safety of the miners who are driving the drifts.

Jan 1, 1998

By James A. Clem

Approximately 2,000 years ago, the Lord Admonished the Scribes (Lawyers) and Pharisees (Religious leaders of that time) that they had paid the tithe but had omitted the weightier matters of law, Judgement, Mercy, and Faith. (Matt. 23:23). I want to talk about "The Weightier Matters of Law." In a situation where big government is trying to have an effect on even small details of a work activity, otherwise simple situations become complex. Regulations are written to such detail that constant compliance with strict interpretations can be a nightmare--not to mention off the target of the intended purpose for the regulation. One soon re- cognizes the oneros characteristics of Federal statues

Jan 1, 1979

By R. G. Reddy

Spent potliner is generated in the electrolytic process of reducing alumina to make aluminum metal using molten fluoride electrolytes. Spent potliner (SPL), obtained at the end of the pots life contains a small amount of cyanide and fluoride which present environmental problems. SPL became a listed hazardous waste under RCRA (K088) in July, 1990. One of the possible uses of spent potliner is as a substitute for Calcium Fluoride (CaF2) as a fluidizer in iron-and steel making and in the glass industry. A low viscosity and a low melting point are prime requirements for accomplishing the above. In the present study, viscosity measurements were performed. Effect of various additives, such as sand, limestone, dicalcium silicate dust, and MgO baghouse dust on the viscosity of SPL was studied. The results showed that with the addition of sand and limestone, very high fluidity of SPL melt can be obtained at significantly low temperatures. The results suggest that spent potliner mixed with additives could potentially be used as a substitute fluidizer.

Jan 1, 1999

By William E. Mead

The process of selecting a building site for a major structure is a complex procedure involving the consideration of a multitude of factors. The approximate geographic location for a structure is usually fixed by its intended function, though often there may be several site alternatives. Socio-economic, logistic, marketing and political factors are the primary site determinants. Also critical in site planning, however, are the environmental factors, both natural and man-made. These factors will influence the precise siting location within the limits allowed by the primary determinants and will dictate some of the basic design criteria. This paper discusses environmental factors, principally those which are natural conditions, that must be analyzed for five different groups of structures. The importance of thorough site environmental analysis based upon the principles of applied earth science is described. Significant elements to be considered in an appraisal of the geology, hydrology, seismology and meteorology are outlined.

Jan 1, 1968

By Thomas B. Faddies

The Trixie mine is located in the East Mining District. Since production began in 1970 over 450 000 tonnes of ore grading 239 grams of silver, 6.9 grams of gold, and 1.2% Cu have been mined from veins in Cambrian Tintic Quartzite. Detailed geologic mapping and extensive sampling are essential for compiling the data base required for efficiently developing and mining known reserves as well as planning exploration and development work. Although the basic techniques used by the geology group at the Trixie were developed many years ago, the reduced activity in underground precious metal mining in the U.S. have made these techniques less familiar to many presently active geologists. The increased activity in precious metals search and exploration again offer cause for the application of these techniques as a prerequisite to efficient exploration, development and production.

Jan 1, 1983

By W. A. Crosby

All mine operators using explosives want to maximize explosive performance while minimizing blasting costs. Use of bulk explosive products such as AN/FO, heavy AN/FO, slurries and emulsions has greatly improved blasting efficiency over the years. Many operators have improved energy output from these products by adding aluminum. A major problem facing them is the fluctuation in aluminum price. The question therefore becomes, when is it economically advantageous to use aluminum in bulk products? This paper answers this question by first reviewing the energy output from the main types of aluminized and non aluminized bulk mixed explosives and then by showing the relationship between the different products on a cost and energy basis. The paper finally presents examples of charts and tables which will aid mine operators to conveniently select the most economically correct bulk explosive, including the level of aluminum addition.

Jan 1, 1991

By Laszlo Valentyik

Heavy media separation (HMS) is one of the most widely used gravity methods in the mineral industry. The feed is separated, according to the specific gravities, into two products; float (light) and sink (heavy) particles. The universal acceptance of the process is due to simplicity, efficiency and robustness for ease of control. However, if optimum separation is desired during the operation of heavy media plants, a delicate balance of a number of variables is essential. Among the variables, the two which are generally the most frequently checked and controlled are specific gravity and consistency of the medium. The latter is a function of the settling rate of the media. The medium is generally made up of finely ground ferrosilicon, magnetite, galena, shale, quartz sand, clay contaminants and water. The frequently present clay in the medium acts as a stabilizing agent, since the coarse heavy medium solids (called media) would quickly settle if they were mixed only in water. Clay concentration of the medium varies between 3-7% by height (1,2). Although clay is essential for reasonable media stability, clay concentration greater than 7-8% imparts too high a viscosity to the medium, and the feed cannot accurately stratify and therefore separate into the required products. To be on the safe side, plant operators clean the medium from most of the clays, and would rather work at a lower stability than have a very viscous medium on their hands. The most recent advance in the area of consistency control rlas made by the introduction of atomized (spherical) ferrosilicon (3). This extended the upper limit of the use of ground ferrosilicon from 3.3 to approximately 3.6, broadening the range of the optimum operating conditions. A viscosity control method was also worked out by the use of low cost additives which lower viscosity while retaining a favorable low setting rate (4). Recently (5) polymers have been successfully used in oil well drilling muds then the requirements were mainly to suspend and transport cuttings during the periodic shutdowns and dril1ings respectively. The rheological properties of these polymer suspensions are such that they present an infinite viscosity to

Jan 1, 1971

By Philip Morey

Large scale surface coal mining will be required to fill future energy demand in the United States. In realization of this long-term commitment to coal resources, the U.S. Energy Re-search and Development Administration sponsored a study to determine the costs and problems of large-scale surface coal mining. As a result of this study a series of computer models were developed that can be used by government and industry to: 1) facilitate mine design and equipment selection, 2) provide detailed analyses of mining and processing costs. Two types of models were developed: detailed simulation models, which provide detailed information on mining systems and equipment to assist in mine design and equipment selection1 and broad models, which provide a first-order evaluation of deposits and new ventures for an entire mining complex. The complete model series permits examination of surface coal mining under a variety of terrain conditions. Six different mining methods were analyzed and documented during the overall project: 1) Area stripping with draglines, 2) Area stripping with draglines, extended bench, 3) Contour stripping with draglines, 4) Area stripping with shovels (loaders) and trucks, 5) Mountain top removal with shovels (loaders) and trucks, 6) Multiple dipping seam mining with shovels (loaders) and trucks. Each major operation in the coal mining pro-cess is represented in these models so that the best methods and equipment may be selected and 50 that the impact of such selection will be reflected in estimates of capital investment, operating costs, and coal price. Individual models allow the user to separately analyze overburden removal, overburden drilling and blasting, coal drilling and blasting, coal loading and hauling, coal preparation and handling, land reclamation, and premining, facilities, and administrative expenses. Because it is impossible to cover all the models in this paper, only the detailed simulation models representative of the technique "area stripping with draglines," are described. The Fort Union Strippable Coal Resource Region, one of eight test cases, is used as an example to describe the models.

Jan 1, 1978

By S. S. Peng

In this paper, the precise definitions for a number of commonly used subsidence parameters are given. The subsidence parameters have been determined using an integrated approach for 110 subsidence cases collected in the major US coal fields. Attempts have been made to establish empirical formulae for the parameters. The results of this study indicate that some traditionally-held concepts should be changed.

Jan 1, 1995

By A. A. Dor

Recent developments in the design of concentration plants have reflected the increased recognition that has been given to the economic and metallurgical advantages of autogenous grinding. This has manifested itself in the increasing adoption of primary auto genous grinding in iron ore 'beneficiation plants in North America. Table 1 lists eleven major iron ore beneficiation plants which have either been put in operation since 1961 or are under construction at present. Seven out of these eleven plants have adopted primary autogenous grinding. Four of them have coarse grinding mills (8 to 14 mesh) and three have fine grinding primary circuits (48 to 65 mesh). Their nominal capacity totals 26. 2 million ltpy of concentrates or pellets, representing very nearly 75% of the aggregate capacity 135. 3 million ltpy) of the eleven concentrators listed. For a long time there was a tendency to consider that primary autogenous grinding was only applicable to suitable coarse grained ores, However, extensive testing of a very wide variety of ores, and actual operating performance in several commercial plants, seem to have established beyond reasonable doubt, that the majority of mineral ores which the beneficiation engineer may be called upon to process can be ground autogenously. The basis for the selection of autogenous or conventional grinding mills, becomes principally economic and depends on the liberation characteristics of the ores under consideration and their relative hardness and grindability.

Jan 1, 1965

By W. D. Bullock

The King-Beaver mine of Asbestos Corporation Limited operates an open pit in the city of Thetford Mines, Quebec. The approximate loca-tion of the open pit is at Latitude 46° 02' North and Longitude 71° 20' West. The general topography is 1020 feet above sea level. Thirty-six percent of the company's scheduled asbestos ore production, for the Thetford Mines area, comes from the King-Beaver pit. The pit operates 24 hours a day, six days a week. Normal production is 10,500 tons of ore per day at a waste to ore ratio of 2 to 1. The remaining ore requirements are mined from the King-Beaver underground mine and the British-Canadian mine.

Jan 1, 1980

By James E. Lawver

During 1981 the Florida phosphate industry produced more than 43 million metric tons of phosphate rock - about one-third of the entire world production and also generated nearly an equal amount of waste clay and waste clay-sized product that requires dewatering and disposal. The material balance of solids and water for a typical Florida phosphate mining operation is shown in Figure 1. Historically, the industry has impounded clay waste (about 60% below ground and 40% above ground) in earthen dams, often as large as 800 acres and occasionally greater than 60 ft. high. The dams have served the triple purpose of: 1. Dewatering initial 3% solid waste clay for process water re-use. 2. A reservoir system to minimize water discharge from the mining area and to capture and store rainwater thus minimizing deep well pumping requirements. 3. The ultimate densification and storage of waste clay.

Jan 1, 1983

By Y. J. Wang

In the mathematical analysis of electrical networks, the electrical devices are often modeled using idealized network elements such as current sources, voltage sources, and resistors. An analogous approach is outlined here for the modeling of mine ventilation networks, which can be considered nonlinear resistive networks. The modeling technique proposed uses five basic (non-reducible) elements: the H element, the Q element, the D element, the R element, and the N element. These elements are characterized by their (a) pressure gain or loss, (b) air quantity, and (c) pressure-versus-quantity relationship, each of which may be known or unknown. In addition to the definition of the basic elements, the necessary conditions for which there exists a unique solution are discussed. This is performed using theoretical developments derived from electrical circuit theory and illustrated in example networks. The proposed procedures are useful in the solution and characterization of mine ventilation networks.

Jan 1, 1996