Search Documents

By D. Saramak, T. Gawenda, Z. Naziemiec, A. Saramak

"Crushing and grinding operations are burdensome to the environment due to generating large amounts of dust, noise and waste during course of comminution operations. An indirect negative contribution of industrial crushing processes is an increase of carbon dioxide emissions, which is a byproduct in energy production processes. On the other hand comminution processes in ore enrichment technology are essential due to liberation the useful minerals from the gangue, and producing the demanded particle size fractions of products. The article concerns investigation over negative influence of comminution devices on environment in terms of dust and noise emissions. Several various crushing devices were under investigations, both in laboratory and in industrial scale.The obtained results were analyzed in terms throughput and energy consumption achieved in various crushing devices. The test results allow to conclude that an intensity of dust generation for individual types of crushing devices is varied. An additional aim of this article is to link the aspect of mineral processing with its environmental impact and hence an influence of raw materials beneficiation industry on the quality of life of residents in immediate and close vicinity.INTRODUCTIONMineral raw materials beneficiation processes are an integral part of multi-stage processing of coal, iron ore and non-ferrous metals, production of aggregates, cement, or precious metals and stones. One of the common features of all beneficiation operations is their high energy consumption, which is mainly connected with various operations of feed particle size reduction. Comminution processes in ore enrichment technology are essential to expose and liberate the useful minerals from the gangue, while in aggregate production processes – to obtain the demanded particle size fractions of products. Crushing operations are characterized by a high degree of negative impact to the environment and humans, mainly due to:• High electricity consumption, which indirectly contributes to the increased emissions of carbon dioxide into the atmosphere, since CO2 is often one of the byproducts of energy production;• Relatively rapid wear of device working parts, what forces a production of spare parts and involvement of steel industry;• Intense dust pollution generated during crushing and grinding processes. This is one of the factors affecting the air quality and the consequent deterioration of the living conditions of inhabitants near mines and processing plants; and • Excessive noise emissions."

Jan 1, 2016

Flotation of a mineral bearing particle is the result of successful completion of a chain of events, such as, producing particles with sufficient exposure of the valuable mineral on the surface, reagent adsorption, suspension of the particle in the pulp, collision of particle with air bubbles and subsequent attachment, ascending to the froth column and transport to the concentrate stream, among others. These sub-processes in turn are affected by the feed properties such as size and density, and process variables such as size of air bubbles, degree of turbulence in the cell, particle/particle interactions etc.. Thus, inefficiencies occurring in any one or more of the above processes will result in inefficient flotation performance. In spite of its dependency on a wide variety of sub-processes, flotation performance is commonly modelled based on first order kinetics using two or three parameter models. As the model parameters may be affected by several of the sub-processes mentioned above, interpretation of their variations and identifying the specific causes is extremely difficult. Of the many factors that influence the flotation performance, liberation information of the particles such as the grade distribution and surface exposure are considered vitally important. In this paper, it has been demonstrated a) how a predictive liberation model may be derived and used in quantifying the liberation information of the particles produced at various grind sizes and b) how the flotation process may be modelled by explicitly incorporating the liberation information, thereby improving the accuracy of the model. Comparisons of the observed data with the proposed model and those of published liberation/flotation models have also been made.

Jan 1, 2016

By F. S. Hoseinian, M. Irannajad, M. Safari

In this study, the effect of chemical interactions of materials used in ion flotation on the removal of Ni(II) ions from low concentration synthetic wastewater was studied. Sodium dodecyl sulfate (SDS) and ethylhexadecyldimethylammonium bromide (EHDABr) as collectors and methyl isobutyl carbonyl (MIBC) and Dowfroth250 as frothers were used. To investigate the effective parameters and interactions of them, 16 experiments including 6 level variables were performed by supporting DX7 software and on the bases of 2-level factorial method. In the first step, the tests were conducted in a Hallimond tube. The result showed that collector of SDS and frother of Dowfroth 250 had appropriate interaction with each other at pH = 3. In the second step, optimal results from the first step were evaluated in a mechanical flotation cell. The removal of Ni(II) ions increased by increasing the time of flotation and they have a direct relation with the water removal. The kinetics study shows that the order and the rate of removal of the reaction do not follow any of the zero-order, first-order and second-order equations. The flotation rate curve on the removal of Ni(II) ions will divide the separation process to two stages, a fast flotation rate at the first stage and a slow flotation rate at the second stage. Ni(II) ions removal was obtained 88% at the best condition.This study showed that the use of ion flotation was a very effective method for Ni(II) ion removal from industrial wastewaters.

Jan 1, 2016

By Liguang Wang

The froth phase in flotation has received much less attention than the pulp phase despite the fact that froth stability plays an important role in determining flotation performance. Froth stability is largely determined by the stability of thin foam films, which in turn has a strong correlation with the critical rupture thickness (Hcr) of the films. In the present work, a new approach to predicting the Hcr values of thin foam films in flotation froth phase was proposed and examined. The Hcr values were calculated using an advanced capillary wave model with input parameters being surface tension, film radius, capillary suction pressure, and intersurface force. The intersurface force was estimated by using the Stefan-Reynolds lubrication approximation to fit the measured thinning rates of single foam films formed in a Scheludko ring cell, where the film radii were less than 50 microns and were kept constant during the film-thinning process. A comparison between the predicted and experimental Hcr values was made for the films with the use of sodium chloride as background electrolyte and in the presence of various frothing reagents such as methyl isobutyl carbinol (MIBC), polypropylene glycol with an average molecular weight of 400 (PPG400), and sodium dodecyl sulphate (SDS), at different concentrations and film radii. It was found that the model correctly predicted the trends of Hcr-versus-concentration and Hcr-versus-film radius curves. Moreover, the predicted Hcr values matched well with the experimental ones of the foam films containing either SDS or PPG400. For the foam films containing MIBC, however, the model overpredicted the Hcr values. The reason for this discrepancy was discussed.

Jan 1, 2016

By H. Langlois

"Included in the Mines Gaspe mining complex located at Murdochville, Quebec, is a copper smelter which comprises a reverberator furnace, two Peirce-Smith converters, an anode furance, and a sulphuric acid plant.The 50% smelter capacity available is supple mentedby custom concentrates for treatment. As these concentrates can be varied and extremely complex many modifications and improvements have been brought about to optimize and make the process more flexible since its inauguration in 1955.IntroductionThe copper smelter of the Mines Gaspe mining complex is located in Murdochville, a small municipality in the heart of the Gaspe peninsula, 90 km northwest of the town of Gaspe .This metallurgical installation has a daily smelting capacity of 650 tonnes of concentrate and an output of 250 tonnes of copper and 900 tonnes of sulphuric acid. Its main components are: a reverberatory furnace, two Peirce-Smith converters, one rotary anode furnace and one acid plant. The gases, which are produced by the converters, are treated at the acid plant then combined with gases from the reverberatory furnace before being vented through a 152 metre high stack .From the beginning of its operation until the present day (1991), the smelter has treated 7 million tonnes of concentrate and 100 thousand tonnes of scrap for a production of 1.8 million tonnes of copper and 2.2 million tonnes of sulphuric acid."

Jan 1, 1993

By D. Sbarbaro

In many modem concentrators the use of supervisory systems in their grinding circuits has meant more consistent operations and increases in capacity. These systems rely on a series of specific algorithms that uses different pieces of information and drives actions over the process. One of these algorithms is the ball mill overload detection, which plays an important role in any supervisory strategy designed to maximize ore feed rate in wet grinding circuits. This paper introduces different overload detection algorithms, and compares them in terms of the time taken to detect the overload condition. This comparative analysis is based on highly noisy power draw measurements obtained in an industrial plant.

Jan 1, 2007

"Batch flotation testwork demonstrated that a low-grade chromite ore from Bird River, Manitoba, was best floated at pH 2 using Armac C (coco amine acetate) collector and sulphuric acid as pH modifier. A grind of 100% minus 150 um was necessary for liberation, and flotation selectivity was greatly enhanced by prior desliming. A concentrate analyzing 24.2% Cr203 with a recovery of 90.2% was obtained, after three cleaning stages, from ore grading 6.05% Cr203. Total rougher collector concentration was 500 g/t and cleaner collector concentration 380 g/t. Similar grade and recovery were obtained during the pitot-plant evalualion, when a concentrate analy zing 22.3% Cr203 with a recovery of 93% (based on deslimed feed) was obtained for a total collector addition of 630 g/t.Selective flotation in a region of positive surf ace charge implies anionic activation, and a possible flotation mechanism is suggested.IntroductionIn an earlier study(1) of the beneficiation of chromite ore from Bird River, Manitoba, several methods of beneficiation were explored. These included ore sorting, heavy-media separation, and gravity concentration with flotation using Armac C (coco amine acetate) collector at pH 2, and sulphuric acid as pH modifier. Because flotation was not fully evaluated, a laboratory study was undertaken to determine the optimum parameters of chromite flotation. Optimization of parameters was established first on a laboratory scale followed by confirmation a t the pilot -plant level. Flotation of chromite using Armac C and sulphuric acid as a pH modifier has been reported as being selective for low-grade chromite ores(2)."

Jan 1, 1990

By Marty Hudyma

Mining-induced seismicity and rockbursting is one of the primary risks in deep mines. Seismic data management software has been created to facilitate analysis of mining-induced seismicity. The Mine Seismicity Risk Analysis Program (MS-RAP) is a purpose built database with mine seismicity analysis tools. One of the primary features of MS-RAP is the creation of seismic hazard maps in quasi-real time. The seismic hazard maps identify areas that are more prone to large seismic events and rockbursts, allowing risk management measures to be focused on the areas of greatest risk. These maps allow mining engineers to be more proactive about identifying and managing seismic related geomechanics risks in mines.

Oct 1, 2009

By W. Dolsak

Introduction Alternative bolting injection resin Hollow bars, rebars, and cable bolts Results from an in-house product development project Sept. 2011 to Feb. 2013 Goals Introduction of a newly developed bolting silicate injection resin as alternative to cement grout based injection systems Definition of easy-to-use pumping devices and installation accessories Accomplishment of installation trials and performance evaluation

May 1, 2013

By C. Poon

For slope stability, knowledge of major and minor discontinuity sets that form the rock mass fabric is paramount for pit slope designs. Due to the increased awareness of health and safety in mining projects, efforts have been made to limit structural mapping in order to minimize the risk to personnel associated with approaching potentially unstable areas. Recognizing the importance of such safety precautions, Golder Associates Ltd. is applying a combination of techniques including 3D photogrammetry, conventional mapping and drilling with core orientation to enhance structural data collection. Photogrammetry uses digital photographs to produce a virtual model of a rock mass surface. The application of these techniques will be exemplified through an expansion design of an existing open pit. A comparison of stereonets obtained using these techniques showed some agreements, but also highlighted limitations of each method. The application of photogrammetry was found to be very useful in complementing the other existing techniques.

May 1, 2009

By A. Kobzhanov, S. Saparova, S. Brochot, D. A. Mango

KATCO (an ORANO Mining and Kazatomprom joint venture) is the largest in-situ leach uranium mining operation in the world, exploiting the Muyunkum and Tortkuduk uranium deposits in southern Kazakhstan. After extraction from the deposits, uranium is then transported via a hydraulic network to be purified in three processing plants located near these deposits. Within KATCO, with the support of ORANO Mining and CASPEO, in 2018 and 2019, a large project that had as its main objective to improve the uranium accounting system was implemented. The objective of this paper is to describe this project and all the changes that it entailed. At KATCO plants, a black-box approach was previously used for uranium accounting. However, it is recommended to use all the available measurements and to deploy a data reconciliation model (between well-fields and plant) as the reconciliation uncertainty is overall lower and it provides a more accurate uranium balance. During the deployment of this project, the rules and algorithms to generate the uranium accounting report, the associated flow diagrams (for uranium accounting), the streams, units of operation, stocks, reporting and Key Performance Indicators calculation rules were re-defined.

Jan 1, 2020

By E. R. Rivenbark

"The coal handling plant represents an investment of about $100 million in coal handling and storage equipment. The coal receiving is done by a continuous ship unloader that can handle ships in the 60 000 T range at Q rate of 1750 /ph. A unique feature in the system is a stacker/reclaimer unit which will work inside a dome storage structure. The coal for the unit will include any low sulphur coal that can be delivered by sea at an economical price blended with New Brunswick high sulphur coal.ThE flue gas scrubber is a wet limestone system capable of 95% SO2 removal. The scrubber will utilize about 150 000 tonnes of limestone per year and will produce commercial grade gypsum by the forced oxidization method.IntroductionWith the need for new generating capacity being required, New Brunswick Power reviewed, in 1985, its options for the next unit. The study indicated that the most attractive option for New Brunswick Power would be a coal-fired unit capable of receiving imported coal at a sea port. The site selection process resulted in three site options being considered.The existing Coleson Cove and Dalhousie sites, and the Belledune site were considered. To meet load distribution needs, it was then decided that the unit had to be located in the northern section of the province, thus eliminating the Coleson Cove site. The Belledune site was selected because it had the capacity to have additional units added where as the Dalhousie site would have only been able to accommodate one unit"

Jan 1, 1994

By R. Phillips, A. G. Doll, D. J. Barratt

"The Bond low energy impact (crushing) work index test is specified to be performed on rock specimens between 50 mm and 75 mm in effective diameter. NQ-diameter drill core, frequently used in mineral exploration programs does not meet that specification, it being 45 mm diameter or less.This paper reports the effect of performing the impact test on contiguous sections of HQ diameter and NQ diameter core, exploring the hypothesis that the contiguous intervals give equivalent results in spite of the core diameter difference."

Jan 1, 2012

By C. Okay Aksoy

In Turkey, the increasing demand for lignite has necessitated an increased emphasis on both lignite production and recovery. This emphasis has resulted in a gradual increase in the application of the retreat longwall mining method for both its product recovery and productivity benefits. Also, in order to maximize the recovery of the natural resources and to increase total production, it is necessary to take advantage of underground reserve before abandoning the mine. This means that at the end of the life of the mine, the main drift safety pillar and the shaft pillar will generally be extracted. This investigation a preliminary study of the stability of the main drift and the shaft at the Hustas Mine as the safety pillars are extracted. In this study, field surveys belonging to the underground colliery of Hustas Co. in Soma have been investigated with the help of LAMODEL working under the Laminated Displacement Discontinuity principle for the models calibrated as a results of physical model and finite element analyses. The convenience of Laminated Displacement Discontinuity Analysis has been researched in such studies. The results out of the models have been coherent with the previous studies.

May 1, 2004

By Balmer Neilly

Early in my term of office it was announced that my Presidential Address would make particular reference to the subject of Mine Taxation in Canada. With this purpose in view there was drafted a Balance Sheet and Earnings' Statement of a Gold Mining Company. This in turn was submitted to the Dominion Income Tax Authorities in Ottawa and to the Minister of. Mines of each of the several Provinces of Canada. The response to the invitation was not as complete as we had hoped it would be, but the figures that were obtained will be presented during the present meeting, and they constitute, I hope, a sufficient basis for extended study and additional enquiry during the year to come ( 1) . In the form letter that accompanied our request to have the submitted earnings assessed, I made the following assertion: "In this work we have three objects in mind. 1.--We will get direct comparison between the different Provinces in Canada. 2.-We will in this way educate our members concerning taxation as it affects the mining industry. 3.-We will publish the details as to how the assessment is calculated by each body, so that a Mine Manager in the most remote district will have a ready reference to guide him in his annual return to the taxing bodies. As things stand, there is no intention of making this a basis for a critical attack on the present rates assessed. It is intended as an authoritative summary of actual conditions as they presently exist".

Jan 1, 1934

By J .. A. Nemes, I. Ragai

This paper discusses one of the common problems associated with sheet metal forming processes, which is spring back. The materials presented here, stainless steel 410 and Inconel 718, are commonly used in aerospace applications for their superior material properties. Standard tensile tests were performed to determine their tensile properties, as well as material anisotropy. In addition, the effect of anisotropy on springback was assessed experimentally through simple multiple-bending experiments in different directions to the rolling direction. Finally, draw-bending experiments were carried out to study the effect of forming conditions, such as blank holding force, on the final springback angles of the formed parts. For both materials, it was found that the R-values measured for different sheets exhibited variation. However, the specimen orientation does not have a large effect on material tensile behavior or springback angle for simple bending. For the Inconel 718 specimens, the springback angle slightly increases with each stage of deformation during multiple bend experiments. The effect of the blank holding force on springback angles was also examined and found to have a significant effect on thin specimens.

Jan 1, 2006

By Roger Moss

OUTLINE Area selection Mineralization/Alteration Styles Island Copper Mineralization Geophysics Geochemistry Coppercorp Setting Mineralization Geophysics Geochemistry Formation Common Characteristics Conclusions

Apr 1, 2005

By M. Bourassa, R. del Villar, S. St. Arnaud, J. Valenzuela

"Autogenous grinding is used quite frequently for mineral comminution as a result of its lower capital and operating costs. However, it is more difficult to control than conventional grinding, particularly when the autogenous or semiautogenous mill is the only comminution stage (i.e. no secondary grinding is available). Analysis of the control strategy used then becomes extremely important, a task that is greatly simplified by the use of an empirical dynamic simulator:This paper presents the methodology used in the development and the calibration of such a simulator for the autogenous grinding circuit of an iron are concentrator: The various steps are described: industrial data acquisition, preliminary treatment of the gathered information. and empirical modelling of the process. Finally, both the actual and the proposed control strategies are compared using simulation results.This exercise has shown that the variability of some of the controlled variables could be reduced through a better handling of the water addition and the use of filters on some of the signals used for control purposes. The reduction in variability of critical variables, such as power draw, would allow their average value to be increased without the risk of exceeding their safety values. Some advanced control techniques were also tested, with interesting results."

Jan 1, 1995

By A. S. H. Kabir, I-H. Jung, J. Su, S. Yue, M. Sanjari

The final mechanical properties of wrought magnesium alloys are mostly controlled by microstructure and crystallographic orientation or texture. In common magnesium alloys, grain coarsening occurs during annealing process and formation of undesirable basal texture cannot be changed markedly. The aim of this work is to investigate the effect of static precipitation on microstructure and texture evolution during annealing at 250 °C after warm rolling of Mg-Al-Sn alloy. Mg-3Al-3Sn (wt. %) alloy has been designed using thermodynamic modeling software, FactSageTM, based on forming target stable and incoherent Mg2Sn precipitate within the industrial deformation temperature range. Microstructures and precipitation were investigated by optical and scanning electron microscopes and macro-texture was measured by X-ray diffraction (XRD) techniques. It was found that static precipitates form in a large scale at the recrystallized grain boundaries and retards the grain growth during annealing. Slight weakening in basal texture was also observed during annealing.

Jan 1, 2014

By Nadarajah Nanthananthan

Mine backfill has been widely used as a means of ground support. While proper design of backfill is important to ensure ground stability, understanding the failure mechanism and the various influencing factors in a filled block is essential. This paper presents a modified sliding failure model of a confined backfill block. The model considers both the gravity load of the backfill itself and the overlying load from fragmented ore or backfill on the top. A series of new equations were derived and the relationships between factors such as factor of safety, friction angle, cohesion and the exposed stope height were developed. This modified model will be a very useful tool in backfill design, for example, to optimize the design of backfill for a given stope geometry or to determine the maximum backfill height for a particular type of backfill.

May 1, 2007