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By Erico Tabosa

The turbulence characteristics and measurement techniques for agitated tanks are well established for liquid and liquid-gas systems. However, the literature shows that the overall energy dissipation rate (related to turbulence) is affected not only by air addition, but also by the concentration of solids. Unfortunately, there are no reliable measurement techniques for characterizing turbulence in a three phase (liquid-solids-gas) environmental system, which is the case in a flotation cell. Therefore, the effect of turbulence on flotation kinetics is very much one of conjecture. The aim of this work was to develop a sensor to characterize the degree of velocity fluctuation, which is related to turbulence, in a flotation cell operating with slurry and air. This sensor comprises a piezoelectric film transducer that converts mechanical to electrical energy. Hence, when the sensor deflects backwards and forwards an AC voltage is created. Flotation studies carried out using this sensor in a 3m3 Metso RCS cell processing a copper sulphide ore showed a highly turbulent impeller zone with transition to a significantly less turbulent zone in the upper portion of the cell. The transition region moves as the cell operating variables are changed, for instance the impeller speed, impeller size, air rate and feed solids concentration. Keywords: mechanical flotation cell hydrodynamics, turbulence characterization

Sep 1, 2012

By A. P. Page, G. E. Alexander, L. L. Sirois, A. A. Winer

A knowledge of the electrical surface characteristics of minerals is all-important in the choice of treatments to up-grade and beneficiate them. At their solid-liquid contacts, there are transfers of ionic species, which for insoluble oxide minerals are the H+ and OH-ions. The adsorption density of these ions can be detected by carrying out potentiometric titrations, and this paper describes the automation of such an apparatus. The details are discussed fully and the validity of the method is demonstrated by flotation tests.

Jan 1, 1969

By Maust. E. J., W. R. Crane

"IntroductionIn the study of mine drainage in the red iron ore mines of the Birmingham district of Alabama, an extensive series of measurements were made in order to determine the drainage from the area overlying and adjacent to the mines. Gaging rods were generally used in measuring streams, and weirs in ditches and sometimes as a check on rod work. These tests in turn were checked by current meter tests. In all, 725 separate stream gagings and 97 weir measurements were made. Certain relationships were worked out, particularly between rod and weir tests, which permitted obtaining results that are much more accurate 'under the existing conditions, than any available formula would give. The large number of weir measurements and the period covered by the tests made it impracticable to construct a weir for each observation so portable, adjustable weirs were built. The methods used are described here for the benefit of those interested in measurement of streams in connection with a study of mine drainage or otherwise. The Drainage AreaThe area draining the mining district lies between the crest of Red Mountain and Little Shades Creek, and for convenience was divided into sub-districts adjacent to certain groups of mines. Gaging stations were established on Little Shades Creek at the upper and lower boundaries of each sub-district, also at points on the tributaries near their junction with the creek. The difference between the volumes of water flowing in Little Shades Creek as it entered and left the sub-districts represents the flow from the tributaries on both sides of the creek. Since the flow coming from the sub-districts was measured direct, the inflow from the tributaries on the opposite side of the creek can be computed from the three volumes determined."

Oct 1, 1926

By F. A. Steward

Copper is one of the trace minerals essential to life. It is added, usually in the form of copper sulfate, to virtually all formulated feedstuffs and to dietary supplements fed to animals on forage. Over the past five years, an improved inorganic copper source trademarked Micronutrients TBCC™, has been developed, tested and commercially introduced. TBCC is a crystalline form of basic copper chloride. Synthesis is accomplished in a continuous neutralization I crystallization process. In current commercial production, the primary sources of copper currently used as feedstocks are the etching solutions used to manufacture electronic printed wiring boards. These solutions have traditionally been managed as hazardous wastes, but their use to manufacture TBCC™ exempts them from regulation as wastes under the "Use/Reuse" provisions of RCRA. Research conducted over five years at multiple universities has shown that animals are healthier when fed this source of copper and that vitamin losses in feed are reduced by its use.

Jan 1, 2000

By Kanchan Mondal, Anthony (Sam) Spearing, Gopi Bylapudi, Joseph C. Hirschi

"The U.S. coal mining industry uses about 100 million rock anchors per year. ASTM F432 specifies the requirements for rock bolts on mines but does not address corrosion. Corrosion has been found to be an issue in Australian coal mines (Hebblewhite et al., 2003 and Villaescusa et al., 2007), where the problem has been researched and stress corrosion has been found to be a significant cause of rock falls. Corrosion is also a major concern for underground civil construction in the U.S. but has not been considered an issue or adequately researched in coal mines. Underground conditions are conducive to corrosion mainly because of water quality and humid conditions. There is a perception, however, that when bolts are fully grouted, adequate corrosion protection is offered to the steel. Research has shown that this is not necessarily the case, due to the formation of micro-cracks as the resin sets and with subsequent rock movement shearing the resin column. This paper outlines a method to determine the corrosion potential of bolts used in long-term excavations and suggests ways to mitigate such effects based on research conducted in the lab and on three mines.INTRODUCTIONResearch on rock anchor corrosion in mines has not been extensive enough in the past, and the effects of several factors in the mine atmosphere and waters are not clearly understood. One probable reason for this lack of research may be attributed to the time required for gathering meaningful data, which makes the study of corrosion quite challenging.Almost all the rock bolts used in coal mines are made from steel, hence the corrosion of iron needs to be understood. The corrosion of iron is an electrochemical phenomenon with the overall equation"

Jan 1, 2010

By Bernard Porter

The solubility of UO2 was determined at 1,250° C. in ternary melts of UF4 and BaF2 with CaF2, LiF, and SrF2. The solubility of Ce02 was measured at 800° and 850° C. in a solution of CeF3, BaF2, and LiF. The amount of La203 which dissolves at 950° C. in a binary mixture of LiF and LaF3 and a ternary of LiF, LaF3, and BaF2 was also measured. In each case, the amount of soluble oxide was mound to be less than 5 weight-percent. A procedure was developed for filtering fused, oxide-saturated fluoride melts in order to obtain a representative sample for chemical analysis. The oxide content of the samples was determined by an inert-gas fusion procedure.

Jan 1, 1961

By J Jeffery, P G. Knott, F Velge, C Evans

A trigger action response plan (TARP) provides a structured response to escalating levels of risk. In mining, TARPs are typically applied to primary hazards such as inrush, strata failure or heating. Necessary for the creation and deployment of a TARP is a monitoring system capable of detecting deviations from normal conditions. The advent of real-time instruments capable of measuring diesel particulate matter now permit decision-making within shifts to address possible overexposure. Deploying a TARP for diesel exhaust emissions can lower the probability of a person’s average exposure (over a full shift) exceeding the exposure standard by detecting deviations of diesel particulate concentrations from normal conditions. This enables pre-emptive action to mitigate or protect. Another goal is to drive ambient air concentrations lower through the application of corrective actions as a result of instances where concentrations exceed ‘normal’.CITATION:Knott, P G, Evans, C, Velge, F and Jeffery, J, 2015. Trigger action response plans for diesel exhaust exposures, in Proceedings The Australian Mine Ventilation Conference, pp 129–132 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By M. Ruel

In today's highly competitive worldwide market, it is becoming extremely important for managers to make sure that all resources are used where needed the most. That way, all resources are generating added value, process control equipments are maintained in an optimal state for best performance, and final product is produced at least cost. Performance monitoring is the only way to ensure that everyone is working on top priorities toward the same goal. How can we add value to these warehouses of data? The data is there and the information is hidden; it is just waiting to be extracted. A process performance monitoring system is able to determine if a loop, a system, a unit, or a plant meets the expected performances. The system prioritizes the areas that need attention. It also provides historical reports of the plant status by areas, by loops, and by identified problems. This information is provided to different categories of users in an appropriate format for each one. The system also includes diagnostics and tools to detect and analyze problems.

Jan 1, 2007

By Adel M. Hanna, Ibrahim M. Mashhour

"Collapsible soil is known as one of the difficult soils, which possesses considerable strength when it is dry and significantly reduced when inundated. In practice, in case of a thick layer, pile foundations are often used to penetrate the collapsible soil to firm soil/rock strata. Inundation of collapsible soil is accompanied by a large and sudden settlement, which may significantly increase the negative skin friction and accordingly the drag loads on the pile’s shaft. Inundation may take place from the running surface-water or raising the groundwater. In case of surface water, the amount of settlement varies, depending on the extent of the wetted zone and the degree of saturation in the soil, while rising groundwater will produce full saturation in the ground and accordingly larger settlement.In the literature, there is lack of reports dealing with the prediction of the drag load on piles in collapsible soils subjected to inundation. This is due to the complexity of modeling collapsible soil analytically. Alternatively; the results of a sophisticated experimental investigation may guide the researcher to develop a model to predict the drag load on these piles.This paper presents the results of a small-scale experimental investigation tailored to measure the soil collapse during inundation and the associated drag load on an endbearing pile’s shaft. Based on the results of the present investigation, the effect of the soil collapse potential and the pressure acting on the soil during inundation on negative skin friction is presented.INTRODUCTIONCollapsible soil is a metastable material, traditionally defined as unsaturated soils that experiences a radical rearrangement of particles and significant reduction of volume upon wetting with or without loading (Bara 1976; Houston et al., 1988). A wide range of soils fall into the category of collapsible soil, including naturally existing types of soils such as: Alluvial flood plains, mud flows, residual soils, colluvial deposits, fans, aeolian or wind-blow deposits sands and silts (loess), volcanic tuffs, gypsum, dispersive clays, loose cemented sands , sodium rich montmorillonite clays (Clemence and Finbarr 1981).Soil wetting and soil saturation may take place as a result of urbanization or natural causes, such as: groundwater level rise, landscape irrigation, broken water pipelines or sewer lines, poor surface drainage, groundwater recharge, cut/fill construction, and moisture increase due to capillary rise. The severity of the outcome depends heavily on the so called collapse potential of the soil, which depends mainly on; soil type, compaction effort, initial water content and stress level at soaking (Houston and Houston, 1997; Ayadat and Hanna, 2007)."

Jan 1, 2015

By W. P. Campbell

In the course of the development of the Red Coulee field, northwest of Coutts, Alberta, a considerable amount of information has been gathered by the Department of the Interior regarding the chemical character of waters encountered in the drilling of wells in this area. The writer, in this paper, has undertaken to assemble the available material with the idea of deducing what relations, if any, may exist between the different waters from the same well, and also how these compare with waters encountered in similar horizons in other wells. From no other district, with which the Department of the Interior has had to do, have there been received so many samples of water, and yet not all the waters logged in the drilling reports were sent in for analysis. The information, therefore, herein contained is not as complete as the writer would have desired, but sufficient evidence has been accumulated to indicate some very definite tendencies in the chemical nature of the waters of this field. The drilling of Red Coulee wells has been carried out exclusively by percussive tools. These permit 'dry' drilling, and, consequently, water-sands are recognized when encountered. Had rotary tools been used, information regarding water-sands would have been very meagre, if not entirely lacking, since, in the mudding-off process, water-sands would have been overlooked, with the result that, should water break through into a completed well, its source would not be known and remedial efforts would be greatly handicapped, if not entirely defeated.

Jan 1, 1931

By Rollie E. Dutton, David A. Stubbs

"A sensor has been developed and tested that is capable of emitting and receiving ultrasonic energy at temperatures exceeding 900°C and pressures above 150 MPa. The sensor works with standard ultrasonic pulser-receivers and has demonstrated the capability of measuring workpiece deformation during hot isostatic pressing (HIP). Details of the sensor design, performance, and coupling of the ultrasound to the workpiece are described. Ultrasonic data acquired by the sensor, in situ, during HIP runs and at elevated temperatures in air are presented.INTRODUCTIONHigh temperature structural components, such as structural castings for jet engines, nickel-base superalloy turbine blades, and ceramic and metal matrix composites made from powders are often densified by hot isostatic pressing (HIP). For powder consolidification, the HIP process involves sealing the powder (and reinforcing fibers for composites) within an evacuated ""Can"" made of a material that softens at high temperatures. A hydrostatic pressure is then applied by pressurizing the inside of the HIP vessel with argon gas (up to 140 MPa). The hydrostatic pressure densities the powder through the elimination of the porosity between the powder particles.This paper presents details of the development and preliminary testing of an ultrasonic displacement sensor that can be used to monitor materials processing, in situ, at temperatures and pressures significantly higher than current ultrasonic displacement sensors. The target processing environment for this sensor is that typically found in a hot isostatic pressure (HIP) vessel, i.e., temperatures exceeding 1000°C and pressures above 138 MP a."

Jan 1, 1997

By Jesus Pascual, Benjamin Cebrian

A new Convention Center is going to be built in the millenary city of Toledo, right in the old city limits. The workings will need to excavate some 80.000 cubic meters of granite, which has, a trench-like structure already blasted for the construction (60 years ago) of a parking lot and a shopping area. Surrounding this trench, some few feet away, there are structures and buildings from the 16th century and remainings from previous times that need to be preserved from any damage caused by blasting. Because of this, a vibration analysis was designed according to the special characteristics of this work. Structures to monitor were located at several levels. It considered three different directions of study in order to evaluate the impact of vibrations of the structures located at three different heights of the granite trench. On top, the historical convent of Santa Fe, with some remaining from the 8th century (Muslim domination of the Iberian Peninsula), on the bottom, the Justice Hall of Toledo with 16th century walls, and, in the middle, a wall and a tower from times of the king Phillip II (16th century, the time of the Spanish Empire).

Jan 1, 2004

By Heikki Häkkänen, Tommi Kauppinen, Navid Khajehzadeh

"There are a variety of methods suitable to analyse elemental and mineralogical contents of rock drill core samples. Current demands are on fast exploration and objective analysis of ore samples. This paper proposes a combination of Laser-Induced Fluorescence (LIF) and image processing, entitled LIF-imaging, as a potential method for automated mineral analysis of the drill core samples. It is shown that LIF-imaging can produce a mineral map of the fluorescent minerals existing on the surface of the drill core samples. The test cases are drill core samples from a Ni-Cu mine situated in Kevitsa, Finland. The main prerequisite of LIF-imaging technique is a reference data, linking colours to the minerals. This study describes the calibration of LIF-imaging technique using precise but slow Raman spectroscopy. Using regularized logistic regression, a model is obtained that classifies the minerals based on their emitted fluorescent colours in the digital images. The abundance of each mineral group is estimated by pixel counting. The results are compared with X-Ray Diffraction laboratory assays performed on the same samples. The results show that the interpretation of the fluorescent minerals through LIF images corresponds to the XRD results. Furthermore, the utilization of the logistic regression to interpret the existing fluorescent minerals greatly improves the technique."

Jan 1, 2014

By A. E. Michon

I am Alfred E. Michon, Vice President- International for Burlington Northern Inc. I work for BN's holding company and my responsibilities include co-ordinating the activities of our eight subsidiary companies as they relate to international commerce--an increasingly important aspect of the overall business of our company. Until last April, I was President of the Fort Worth and Denver and Colorado and Southern railroads, subsidiaries of BN. Prior to that, I headed the marketing and pricing area of BN's coal transportation business. Based on my experience in the energy industry, both domestic and international, I would like to discuss the world-wide trend towards the reliance on low-sulfur coal in lieu of natural gas and oil for the generation of electricity. Since pontification on the energy scene world- wide is best left to consultants with scenario-spitting computers, let me in- stead emphasize this trend through two examples. First I will describe the regulatory and economic factors which have encouraged the replacement of natural gas by low sulfur coal as a boiler fuel in the US. BN's investments in track and equipment were instrumental in this conversion. Secondly, I will show how this same combination of factors has created a large demand for steam coal in the Far East. Again, our company's strategy is to facilitate conversion to coal overseas through timely and sufficient investments.

Jan 1, 1982

By E. J. Wasp, T. L. Thompson, T. C. Aude

The paper will deal with some of the more important technical aspects of slurry pipelines as they apply to the mineral field. In addition, the use of these technical concepts in arriving at realistic economic figures will be discussed.

Jan 1, 1970

By Richard J. Kline

The underground mining industry is presently using the fluid network analyzer and digital computer to analyze ventilation systems. The availability of the digital computer and ventilation programs to mining companies has escalated its use, permitting the design and modification of new or existing mine ventilation systems to be projected completely and thoroughly with consistent precision. Because the analog computer has been analyzing ventilation systems accurately for many years, a comparison of the analog and digital methods was warranted. This report summarizes a detailed comparison for one mine, based on parallel analyses by the two computer systems.

Jan 1, 1972

By Sheng Zhang

The compressive strength of coal in Yanlong mine area of China is less than 3 MPa. Basically, it is powdery. The roof and floor rocks are mudstone. Therefore this coal seam is a typical ?three soft? coal seam. Roof bolting cannot be used due to the very soft strata. When the conventional U-steel support was used, roadways deformation exceeded 30% of its original dimensions in some sections one half month after development. The required repair work was huge, seriously affecting the daily mine production. This paper describes how to support the soft coal roadways. The deformation characteristics of soft coal roadway were investigated. The conventional U-steel support is not subjected to uniform load, so the whole supporting structure must be strengthened. In addition, drilling holes in the coal seam can transfer high stress from near the ribs to the deeper parts of the surrounding strata, which is beneficial to the stability of the roadway. This new support method is to combine the strengthened U-steel support with pressure-relieving drill holes, providing an economic and efficient way to support the very soft coal roadways.

Jan 1, 2013

By Fabio Mielli

In these times of increasing costs and diminished returns, energy consumption is one source of savings that remains relatively untapped in the mining sector. Typically, 15% to 40% of operational costs can be attributed to energy in mining operations. This ?process variable? is a complex, multi-faceted variable that involves government regulations, societal pressures, cost and competitiveness. A mining company able to successfully embrace an energy efficiency program is more often than not a successful mining company. Production optimization programs, relatively common today, provide increased production, increased availability of assets and, in many cases, improved quality. They generally ignore the energy question altogether. Production Energy Optimization combines reductions in energy consumption with production improvements to reduce the cost per unit of production while improving emissions reporting. An energy strategy in mining and mineral processing operations is a critical component of Production Energy Optimization. This strategy must support the financial and operational integrity of the business. Developing a successful energy strategy requires a well structured approach such as following: ??Understanding where energy is being used and why, ??Recommending and implementing energy conservation measures, ??Driving visibility to targets and results, ??Re-evaluating continuously. The objective of this paper is to help you better understand the process, tools and technologies that enable mining organizations today to address energy and sustainability issues more tactically and proactively.

Aug 1, 2013

In this paper, response surface methodology was applied to optimize the experimental conditions for the wet grinding of synthetic rutile. The effects of parameters such as rotation speed, solids concentration and duration of grinding on grinding efficiency were systematically investigated and the process conditions were optimized, using a nonlinear regression model based on central composite design. The statistical analysis of the results showed that in the range studied, the grinding efficiency of synthetic rutile was significantly affected by the rotation speed of the conical ball mill. According to results from analysis of variance, the value of the determination coefficient (R2=0.9989) indicates that the predicted values are found to be in good agreement with experimental values. The optimized experimental conditions were as follows: a rotation speed of 350 rpm, a solids concentration of 27.31% and a grinding time of 50.31 min, respectively. Under optimum conditions, the predicted grinding efficiency of 94.79% is obtained. The experimental values from the validation experiments were well within the predicted value of the model.

Jan 1, 2011

By M. L. Wacker

"Cigar Lake high-grade uranium mine in Saskatchewan is operating after 25 years of test mining, construction, and mine flood remediation. Factors include ground stability, groundwater control, radiation exposure, and ore handling. A 10 year test program resulted in validating “jet boring”, a non-entry mining method involving artificially freezing the orebody and surrounding rock; tunnelling to develop access crosscuts below the orebody; installing cased pilot holes through ore; extracting ore using rotating high-pressure water jets within pilot holes; and cavity concrete backfilling. Ore slurry is prepared underground, pumped to surface, and trucked to McClean Lake mill for processing to uranium concentrate.RÉSUMÉ Après 25 années d’essais sur les méthodes minières, de construction et d’assainissement suivant les inondations à la mine, l’exploitation de minerai à haute teneur en uranium Cigar Lake, localisée dans la province de la Saskatchewan, est opérationnelle. Les principales difficultés concernent la stabilité du terrain, le contrôle des eaux souterraines, l’exposition aux rayonnements et la manutention du minerai. Un programme d’essai de 10 ans a abouti à la validation du « forage à érosion », une méthode minière qui consiste à congeler artificiellement le corps minéralisé et les roches environnantes ; à creuser des tunnels pour développer des travers-bancs d’accès en dessous du corps minéralisé ; à installer des puits de fondation pilotes à travers le minerai ; à extraire le minerai à l’aide de jets d’eau à haute pression dans les puits pilotes ; et à remblayer les cavités avec du béton. La boue de minerai est préparée sous terre, pompée vers la surface puis transportée par camion jusqu’à l’usine de concentration de McClean Lake pour le traitement afin d’obtenir du concentré d’uranium.INTRODUCTIONThe Cigar Lake deposit is in northern Saskatchewan, 660 km north of Saskatoon, Saskatchewan, Canada, at the east edge of the Athabasca basin (Figure 1; Bishop, Mainville, & Yesnik, 2016). The operation is jointly owned by Cameco Corporation, AREVA Resources Canada Inc., Idemitsu Canada Resources Ltd., and TEPCO Resources Inc. Cameco has been the operator of Cigar Lake since January 2002. The discovery hole was drilled in 1981. Commercial production was declared in May 2015 and the Phase 1 operation will have a mine life of 15 years."

Jan 1, 2017