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By George E. Aiken

Agglomeration developments in the iron ore industry of North America are closely related to shifting patterns in commercially acceptable ore grades and even the definition of iron ores. These relationships have occurred mainly during the last 20 years. Many of these changes are an outgrowth of events which involved the history of the Mesabi Range. Although magnetic taconites had been discovered in the Lake Superior area about 1870, they remained unvrorked in part for lack of concentration methods and a generally unfavorable economic climate. Some 20 years later the rich Mesabi hematites were found beginning the era of direct shipping ores which continued through World War II. These Lake Superior iron ores included reserves of an estimated three billion tons. Following World War II, decreasing ore grades and rising costs began to force the closing of many underground iron mines. The early 50's saw the beginning of the decline in direct shipping ores and a spurt in produc- tion of natural iron concentrates. However, the market for unprocessed concentrates began to decline in the early 60's as agglomerated products and foreign ore s began to dominate the U. S. market.

Jan 1, 1973

By Yang Song, Li Shaokang, Wang Zhiqiang, Wang Jinjun, Li Guofeng, Su Meixuan

The paper investigates the triboelectric charging properties of calcium carbonate (CaCO3) particles under different conditions using a cyclone tribocharger. It explores the effects of airflow velocity, tribocharge material, and particle moving distance on the charge-to-mass ratio of CaCO3 particles. The study aims to provide guidance for the design of triboelectric separation systems for magnesite.

Sep 1, 2023

By Z. Hajnal

Three years ago a research program was initiated at the University of Saskatchewan to develop seismic surveying techniques for use in the Precambrian geological environment. The success of the reflection method in many younger geological settings suggested that this is the technique which would be the most suitable for experimentation. A successful adaptation of this technique to the Shield environment would make mapping of rock formations possible to much greater depth than is possible at the present time with any other applied geophysical technique. This presentation attempts to illustrate the advances which have been made in this program and will provide some insight into future plans. The field investigations were limited to the Flin Flon basin near to the town of Flin Flon, Manitoba (Fig. 1). This area was chosen because the surface geology has been mapped in great detail and it is a very important base metal producing region. It is an ancient sedimentary basin with some characteristics similar to areas where the reflection method has been successful.

Jan 1, 1976

By D. Tao

Reverse cationic flotation is the most widely utilized flotation method for concentrating iron ore. In this process, quartz is often floated with ether amines (R?(OCH2)3?NH2) partially neutralized with acetic acid. However, it is well known that the cationic flotation of quartz does not work well if a certain amount of slime is present in the ore slurry. To improve flotation performance, starch is often added to the flotation feed to selectively flocculate and depress the iron minerals and sodium silicate is used to disperse the silica gangue. The present study was conducted to improve the efficiency of iron ore flotation by the use of a new type of depressant for clay and iron minerals, Georgia Pacific (GP) clay binder. The GP clay binder minimizes slime adsorption on quartz and hematite particles by agglomerating clay particles to reduce their surface area. It also helps depress hematite flotation due to its unique chelating action on iron ions. The results from this study show that the GP clay binder is an effective depressant in iron ore flotation. When it was used as a substitute for corn starch, it increased concentrate grade from 60.78% to 67.67% and increased iron recovery from 71.96% to 72.90%. The combined use of GP clay binder with corn starch produced even better flotation performance, increasing iron recovery to 78.15%, while the concentrate grade remained stable at 67.08%. Keywords: Georgia Pacific clay binder, Iron ore flotation, Flotation efficiency

Jan 1, 2010

By A. L. Coello Velázquez

The subject of this paper is particle population balance models (PBM) that describe mineral impact crushing behavior; it is mainly concerned with the selection and fragmentation distribution function due to their importance in this context. The data obtained by Datta (1999) by applying impact pendulum testing to single limestone particles, used by Austin (2002, 2004a and 2004b) to obtain the principal parity of fragmentation functions, were processed in order to compare them with the results of other authors, such as Nikolov (2002 and 2004) and Vogel and Peukert (2003 and 2005) so as to increase knowledge of impact crushing. From this data it has been possible to obtain the performance models of the principal parameters of fragmentation function, thereby reducing the number of experiments necessary to model the impact crushing process. The authors also propose a simplification of the selection function model posited by Austin (2002).

Jan 1, 2011

By A. Arik

Reliable ore reserve estimates for deposits with highly skewed grade disributions are difficult tasks to perform. Although some recent geostatistical techniques are available to handle problems with these estimations, ordinary kriging or conventional interpolation methods are still widely used to estimate the ore reserves for such deposits. The estimation results can be very sensitive to the search parameters used during the interpolation of grades with these methods. This paper compares the ore reserve estimates from ordinary kriging using several cases in which certain search parameters are varied. The comparisons are extended to different mineralizations to show the changing effects of these parameters.

Jan 1, 1990

By Rollin A. Slater

The bulk materials handling industry has served silently for years as the skeleton structure and often the central system of nerves and nourishment for the body of basic production industries. During the past two decades, this body has undergone substantial growth and mutation to meet the surging demands of our national economy for more and better products. The steel industry has been prominent in this phenomena and plants of the sixties are as unlike the second war vintage as our current crop of basketball players differ from their fathers. Steel has kept pace with spiralling demand by innovation which has resulted in new processes and improved designs which generally yield greater production from fewer units. The supporting industry of materials handling has likewise improved its techniques and currently has a new stronger generation of equipment to perform its necessary supporting function. It has been my fortunate experience to have been instrumental in the creative stages of several new steel mills which are currently in conceptual design or actual construction. Drawing upon exerpts from this experience, this paper will describe a basic approach to the selection and application of modern bulk materials handling systems to an entirely new steel plant. Specific details of past work are not available for publication, therefore, the plant described herein is a composite of ideas and will be the new plant of the Hypothetical Steel Corporation which will be located on the lower shores of the Great Lakes.

Jan 1, 1967

By Robert W. Burns

Gentlemen, my subject today is glass reinforced plastics. By definition, this encompasses a wide variety of materials: at least a half dozen basic varieties of polyester, epoxy, and phenolic; virtually infinite compounding variations within the basic groups: literally limitless variations in the amount and the nature of the glass reinforcing. Complicating all of this is the fact that different modes of application of the same material fall appreciably alter' the product's general strength and suitability. These many, many differing materials are what we conveniently call "glass reinforced plastics" or, more simply, fiberglass". This common name is actually a large part of the problem when dealing with fiberglass materials. Far too often a specification is written calling for simply "fiberglass reinforced polyester', based on successful prior use of a polyester laminate. Such a specification is very nearly worthless since such tremendous variation is possible under it. Success of a laminate furnished under such a specification is entirely dependent on good fortune

Jan 1, 1962

By R. Venugopal, V. K. Saxena, A. K. Mukherjee

"Coal, iron and manganese ore samples were exposed to different ultrasonic intensities of 250, 300 and 350 W/L for five minutes and to an ultrosonic intensity of 270 W/L for different time durations of 3, 5 and 7 minutes. The ultrasonically treated samples showed reductions in D80 particle diameters of 6 percent for the coal samples, 5.95 percent for the iron ore samples and 35.63 percent for the manganese ore samples during grinding. The ultrasonic treatment was also observed to assist in reducing ash content in the coal product by 8 percent and to reduce manganese losses in rejects by about 5 percent. Ultrasonic treatment was concluded to be capable of assisting in the comminution of friable ores more prominently than the hard and porous materials.IntroductionComminution is an important unit operation in the mineral-processing, cement-making, powergeneration and pharmaceutical industries. But most of the milling technologies are considered to be energy inefficient, with less energy consumed in real size reduction and most of the energy consumed in the machine. This is more critical for the mineralprocessing industry because of the growing need to exploit lower-grade ore bodies and process rejects (Blazy et al., 1994; U.S. Department of Energy, 2005). Low-grade ores require crushing and grinding to liberate the valuable minerals, which are further separated from gangues by various beneficiation methods such as gravity separation, flotation and leaching. Various studies have been carried out to minimize energy consumption during milling by developing pretreatment methods that can initiate new fractures or improve the fracture density in materials before comminution. These studies were mainly focused on chemical additives; thermal, ultrasonic and microwave treatments; and electric disintegration (Klimpel and Austin, 1982; Norgate and Weller, 1994; Bearman, Briggs and Kojovic, 1997; Gaete-Garreton, Vargas-Hermandez and Velasquez-Lambert, 2000; Kumar et al., 2010; Wang, Shi and Manlapig., 2011, Singh et al., 2012).The fragmentation effect of ultrasonic fields in solids has been investigated since the 1950s, and Gärtner was probably the first researcher who attempted it (Gaete-Garreton, Vargas- Hermandez and Velasquez-Lambert, 2000). Sound waves can propagate in solids in the form of longitudinal waves, shear waves and surface waves, and in thin materials as plate waves.In surfaces, fractures and interfaces, various types of elliptical or complex vibrations of the particles make other waves possible. During ultrasonic-vibration treatment, cavitation bubbles nucleate, grow and collapse, generating microjets, whose impacts on the particles initiate microcracks. The ultrasonic waves can enhance the nucleation, growth and coalescence of flaws, caused by tensile or shear stress. The mechanisms operating in the materials and inducing these stresses have been identified as spall and compression-induced tensile microcracks, nucleating at preexisting flaws. These mechanisms are driven by the shock wave and cavitation effects in the surrounding fluid (Chen, Huang and Shih, 2003)"

Jan 1, 2016

By P. K. Chatterjee

Computer aided design and inter active graphics have been well established in the electronics, automotive and mechanical engineering industries. The use of such aids in underground mine design and planning, however, has been noticeably absent. The large expense involved in the research and development of CAD and graphics systems and their highly specialized techniques have rendered investment in these areas difficult to justify. Optimum mine planning involves an interactive procedure of evaluation of several alternative plans. Generally the development of each mine plan of a given operation can take many man-months. This time constraint on planning precludes any comparative analysis and evaluation of alternatives, thereby introducing the possibility of unrealized gains. This paper outlines the development of a computer aided mine design program utilizing interactive graphics for the design, simulation and scheduling of underground coal mines. The program developed examines exploratory borehole information and produces a structured database of the sampled data. This database is utilized to generate seam sections and different mine layouts. A simulation of mine extraction and production levels and a schedule of proposed alternatives are then performed.

Jan 1, 1984

By Ehsan Moradabadi, Debra F. Laefer

"To more rigorously address tunneling risks to above-ground structures, vulnerability evaluation of all structures along a tunnel route is required. This multi-block area along the route can be considered a district. To fully assess each structure within a tunnel’s zone of influence, a multi-block or district-level model may provide new insights as to risk evaluation and mitigation strategies. However populating such a model with the existing geometry of the built environment poses a major challenge as measured drawings are not readily available for all structures along a tunnel’s route. Cost-effective population of such a model could arguably involve remote sensing data in the form of laser scanning or photogramme-try. However even for unreinforced masonry structures, where external, above-ground geometries can be captured, without a prohibitively expensive building-by-building, in person survey many factors would remain unknown. To consider these uncertainties in an automatic way, a performance assess-ment framework is proposed. Such a framework allows a more rigorous, initial, risk quantification than is currently possible within the simple empirical models generally being used in industry when tunneling risk is initially assessed. This paper introduces (within the allowable space limits of this format) consider-ations for auto-population and application of a district-level, tunnel-risk screening tool. INTRODUCTION Challenging topography, intense urbanization and infrastructure development, combined with limited land availability and a growing awareness of environmental issues have lead to increasing usage of un-derground spaces to control aboveground traffic and provide essential services in metropolitan areas. Tunneling, however, is not without its own risks, especially with respect to aboveground structures whether it be widespread minor damage (Burland et al. 2001) or the more notable, although less fre-quent, large-scale collapses such as the 2003 Shanghai (Allianz 2015) or 2004 Singapore (Magnus et al. 2005) events."

Jan 1, 2016

By R. L. Grayson

A goal programming-based worker scheduling model has been incorporated in the Mine Management Support System (MMSS) for assigning workers to prioritized jobs on a shift basis. In the model the accomplishment of each regular and non-regular job is a goal. The objective is minimization of the deviations away from the goals. A number of coefficients are used as premultipliers of the decision variables in order to address practical considerations associated with the utilization of workers and the requirements of jobs. Some of these premultipliers will be updated expertly within MMSS, timely updating the statuses of the dynamic parameters.

Jan 1, 1991

By Christopher J. Farrow

This paper describes the grinding circuits installed at two remote sites in northern Canada. One is Cominco's Polaris Project at Little Cornwallis Island; a barge-mounted lead/zinc concentrator. The other is Echo Bay Mines' Lupin Project at Contwoyto Lake, 400 km northeast of Yellowknife, a gold mine, all components of which had to be flown to the site. Logistics and considerations of operating and maintenance presented challenges which were met by innovative design. The evolution of the grinding circuits is discussed. Both plants are operating at design throughput.

Jan 1, 1983

By Gary D. Aho

The United States on a daily basis no consumes about 15MM barrels (2.38 x 106m3) of oil; 5MM (0.79 x 106 m3) of this is imported. This compares tai a daily consumption of 18MM (2.86 x 106 m3) in 1980 when we imported 8MM (1.27 x 106 m3). We are producing the 10MM barrels (1.59 x 106 m3 ) of conventional oil at home from what amounts to just 2% of our domestic energy reserves. Nearly 90% of our total domestic energy reserves occurs in solid forms such as coal, oil shale, and tar sands; this is more than enough to meet our needs for the next 100 years. Worldwide, oil shale is second only to coal as a potential source of energy and the U.S. has approximately one-half of the world oil shale reserves which average over 25 gallons per ton (10.43 x 10-2 L/kg). Since the United States has immense oil shale resources, including some of the richest in the world, and since oil shale produces a superior transportation fuel, it would seem logical that the U.S. would be prudently developing this domestic resource. Unfortunately, despite over 50 years of research and a number of false starts, there is not a commercial shale oil industry in place today. There are a number of recurring roadblocks which have hindered private industry's efforts to develop oil shale and we will look at some of these.

Jan 1, 1983

By Robert Mermelstein, Robert W. Kilpper

In a long term toxicology study SPF, F-344 rats were exposed 6 hours/day, 5 days/week for up to 24-months to a special test toner at 0, 1 (low), 4 (medium), and 16 (high) mg/m3, or Ti02 at 5 mg/m3, or Si02 at 1 mg/m3 by the inhalation route. The test toner was composed of about 90% random, high molecular weight acrylic copolymer and 10% high purity, medium color, furnace type, carbon black. It was enriched in fine particles such that the respirable aerosol concentrations (ACGIH) were to 0, 0.35, 1.4 and 5.6 mg/m3. There were no effects of exposure on survival, causes of death, body weight, food consumption or clinical chemistry and hematology parameters. There was no evidence for systemic or upper respiratory system toxicity as all of the changes were restricted to the lungs and associated lymph nodes. The lung tumor frequencies in the control (air and Ti02) and toner exposed groups were comparable. There were no changes at the low exposure level, which is the most relevant in regard to potential human exposures. The lung changes at the high exposure level consisted of decreased alveolar clearance, increased toner retention, increased lung weight, chronic inflammation, decreased pulmonary function and a moderate degree of focal fibrosis in all animals. The changes in the middle exposure level were smaller in magnitude than at the high level, and a very slight degree of fibrosis was found in 20% of the animals. In a follow-up investigation, female F-344 rats were exposed to one of three toner concentrations; control, low (10 mg/m3) or high (40 mg/m3) for 13 weeks followed by five, 13 week observation intervals. At the low exposure level, slight clearance retardation and modest inflammatory changes were observed at the end of exposure. They returned to normal values within six months post-exposure. In contrast, at the high exposure level, increased lung weight, decreased alveolar clearance and a disproportionate increase in toner retention, as well as an inflammatory response, were noted, which persisted throughout the post-exposure interval. While no significant histopathological changes were noted at the end of exposure, a very slight degree of fibrosis was observed in all of the animals in the high exposure group, after 65 weeks of observation. All of the above alterations are ascribable to "lung overloading", a generic response to excessive amounts of any dust retained in the lungs for a prolonged time interval. Published accounts in the toxicology literature document that long-term inhalation of large quantities of even innocuous particles such as Ti02, carbon black, petroleum coke, toner, and other polymeric and insoluble materials has resulted in a spectrum of generically similar pulmonary changes. Scaling of the rat-data, using 1 mg dust/g of lung as a threshold for "lung overloading", normal ventilatory parameters and 300-500 day human retention halftimes project "lung overloading" upon long-term exposure to insoluble respirable dust above 0.2-0.33 mg/m3. Other types of information are consistent with an exposure limit in the range of 0.4-1.0 mg/m3 for respirable dust. The absence of definitive toxicology data in support of the current OSHA respirable nuisance dust limit, coupled with the lack of sound epidemiology data, indicate the need to reexamine the validity of the current nuisance dust health standard.

Jan 1, 1991

By Raja V. Ramani

In many instances, the actual production from a longwall face does not equal the planned capacity. General problem areas which have been identified include face length and panel depth, face area and gate entry roof support, face conveyor and shearer wear, outby haulage system failures, number of entries in longwall gate development and longwall move time. The performance of a longwall face is totally dependent on the interaction of these and many other factors. To explore fully these interactions, a systems analysis of longwalls has been performed. In this paper, the systems approach, the factors considered in the analysis, and the results of the analysis are presented.

Jan 1, 1983

By M. D. Scott

Lornex Mining Corporation operates an open pit porphyry copper mine in the Highland Valley southwest of Kamloops with a rated capacity of 43 500 TPD (48,000 TPD). It went into production in April 1972. Its concentrator consists of two grinding and flotation circuits in parallel each composed of a 6 000 KW (8,000 HP) 9,75 m (32 foot) diameter by 4,724 m (15'-6") semi-autogenous primary mill feeding two 3 000 KW (4,000 HP) 5,029 m (16.5 foot) diameter by 7,01 m (23 foot) secondary ball mills each feeding a bank of flotation cells. ,The original tailings system picked up the tailings from the flota¬tion circuits in a concrete collection box in the mill and carried the 36% solids density by weight slurry 488 m (1,600LF) through a 1100 mm (42 inch) diameter wood stave pipeline on a .46 percent slope to three 99,06 m (325 foot) diameter center drive thickeners. From the collection box under the thickeners the tailings line con¬sisted of three sections, carrying 50% solids density slurry. The first section consisted of 1460 m (4,800 LF) of 910 mm (36 inch) asbestos cement pipe for gravity flow from the thickener under flow elevation of 1252,4 m (4,109 feet) to the first pump station at elevation 1207,6 m (3,962 feet). Eight concrete drop boxes were used to limit the maximum slope on the pipeline to 0.5 percent.

Jan 1, 1976

By A. B. Cecala

An evaluation was recently performed on a district recirculation system at a trona mine in Granger, Wyoming. A 1.52m (5 ft) diameter, 37.3kw (50 hp) vane axial fan was installed in a crosscut between the intake and return airways and recirculated approximately 31.4 m'/sec (66,578 ft'/min) of air back into the intake. This amounted to a recirculation factor of approximately 20 pct of the return air. This air was part of the primary ventilation to three different continuous miner sections at operating distances of between 6l0m (2,000 ft) and 1,829m (6,000 ft) from the recirculation fan. The mine environment was constantly monitored for respirable dust, methane, and carbon monoxide in the operating sections and in the main intake and return entries. In addition, air samples were taken with and without the recirculation system during the evaluation and analyzed using gas chromatography. The results of this study showed only small increases in dust, while all other mine contaminants remained at such low levels that it was impossible to determine any relative changes from the recirculation system. Because of this, a brief SF. tracer gas analysis study was subsequently performed to more precisely determine an increase in a mine contaminant with the recirculation system.

Jan 1, 1991

By Edmond F. Lawrence

The Calico area lies within the Walker Lane fault zone, six miles north of Schurz, Nevada. The mineralized area is overlain by a thick section of Tertiary tuffs and ash-flows, that have been intruded by a series of andesite plug, dikes, and sills. The pre-Tertiary rocks outcrops only in two areas at one to two miles distance from the drilling areas. Underlying the volcanics are sediments ranging from siltstones, sandstone, calcareous shales, to carbonates of the Luning sequence. These have been intruded by one or more phaneritic intrusives ranging in composition from quartz diorite to quartz monzonite, with the development of a skarn zone on the south flank that contains extensive mineralization consisting of magnetite, pyrrhotite, pyrite, and chalcopytite, with traces of sphalerite, galena, and molybdenite. The magnetite, pyrrhotite, and part of the pyrite appears to be contemporaneous with the skarn, while, part of the chalcopyrite, galena, sphalerite, molybdenite, quartz, and calcite, occurs as minute veinlets cutting the other minerals. This later mineralization may be associated with a late stage of the same sequence, or possibly associated with another intrusive to the southwest. Geophysical work has consisted of aerial magnetics, ground magnetics, gravity, seismic, and induced polarization surveys. Preliminary induced polarization surveys indicated anomalies at depth, both over the magnetic anomaly and to the northwest. Subsequent IP work confirmed this earlier anomaly, and drilling disclosed extensive mineralization at depths of 400 feet on the northwest end and over 1,000 feet to the southeast.

Jan 1, 1967

By Clark Harrison

It is not uncommon for overall quality of coal from a mine to deteriorate as the mine is developed or for an improved-quality coal specification to be imposed during the life of the mine. Either of these conditions typically results in management pressuring mine personnel to take greater care in delineating the seam from top and bottom rock. When mining and seam conditions require a portion of the seam to be removed to ensure sufficient rock is removed to meet the quality specification, physical-coal cleaning may become economically competitive with in-pit seam grooming. The additional cost of coal cleaning may, in some cases, be justified by permitting higher recovery of the coal seam than is possible when cleaning the seam with excavators in the pit. This paper compares projected coal cleaning results with present in-pit grooming techniques and reports the economic results.

Jan 1, 1987