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By C Garrido, J Barrera, H Alvarez, L Perez, S Ramirez

In recent years, there has had a greater recurrence of studies and projects that consider tailings filtration followed by dry stacking to reduce the consumption of fresh water, the space required for disposal, and, eventually, to reduce the costs of the project. In addition, this technique could be required to meet new environmental restrictions to extend the life-of-mine of existing plants or to enable the development of new projects, especially in areas of high social interest. This article is intended to describe the most relevant technical aspects of the design and implementation of an iron ore tailings filtering system and its final overland disposal as well as physical and metallurgical surveys, and laboratory and pilot testing. Furthermore, it is presented how these activities are inserted in the project development to rationalise the resources. The case under study considers an iron mineral wet magnetic concentration processing plant. The outcome tailings are dewatered by means of thickeners, where the overflow water is recycled back to the plant. The underflow slurry is pumped into intermediate storage tanks before proceeding with further dewatering and final disposal. The project consists of a tailings filtration plant, belt conveying systems, a temporary stockpiling system, trucking loading and transportation system, moisture-conditioning facilities (spreading and airing), and final disposal facilities (compacting). Due to the stickiness of the filtered tailings that governs the belt conveying system design, the operating moisture range must be established. Besides, proper technical aspects such as planning, executing, and analysing both the laboratory and the pilot testing data to validate process design parameters; selecting filters; defining spare filtering capacity; handling the out-of-range filtrated moisture; sizing the belt conveying system; configuring the equipment involved, must be considered.

Nov 8, 2021

By H Weitz

Bateman Engineering provided process technology and engineering design to China Yunnan Metallurgical Company (CYMCO) for a 30 MW DC furnace for the production of high-grade titanium dioxide slag.Following the successful commissioning of the furnace during the latter part of 2009 and the first quarter of 2010, a period of adverse circumstances resulted in having to operate the furnace without feed and at a low power input for a period of time. When normal feed resumed, a layer of solid material was detected on the slag-iron interface during sounding measurements. The condition of the iron was also significantly altered. The iron temperature was much higher than the design value, but the carbon content had decreased to such an extent that a large amount of iron solidified in the furnace, which made iron tapping very challenging. The slag temperature was increased in order to melt the solidified iron. However, severe sidewall damage resulted, which finally led to a burn-through. A number of samples were taken from the slag that remained in the furnace. These samples were analysed to determine the chemistry and phase profile throughout the slag bath. The mechanisms of formation of the high melting-temperature phase on the slag-iron interface are discussed, as well as procedures that can be applied to prevent a recurrence of this phenomenon. Some recommendations are made for instances when furnace feeding is interrupted for an indeterminate period.

Oct 5, 2011

By M. K. Mohanty, H. Akbari, L. A. Ackah

Dry separation was the predominant method of coal cleaning in the United States from the 1930s to 1980s. The application peak of dry separators for cleaning raw coal was in 1965, when about 23.1 Mt of cleaned bituminous coal was produced. The main advantage of dry coal cleaning is the elimination RIWKH GHZDWHULQJ VWDJHV DQG VLJQL¿FDQWO\ UHGXFHG moisture in comparison to wet processing. In addition, developed dust control systems have made dry cleaning method an environmentally friendly process. The largest air-based coal cleaning plant was built in Pennsylvania in 1968 and could clean 1,272 t/h of raw coal sized smaller than 19 mm. This was followed by a decline in dry coal cleaning to less than 3.6 Mt in 1988. Some of the main reasons that shifted coal operations IURPGU\WRZHWSURFHVVLQJZHUHWKHQHHGIRUPRUHHI¿FLHQW separations with lower density cuts, increase in raw coal surIDFHPRLVWXUHVSHFL¿FDOO\LQXQGHUJURXQGPLQLQJWRFRQWURO GXVW ¿QHUSDUWLFOHVL]HUHTXLUHPHQWV LQFUHDVHLQ¿QHVLQUDZ coal from underground mines, and health and safety concerns related to dust and noise (Arnold, Hervol and Leonard III, 1991; Miller, 2011).

By J. Jirestig

Poor grade iron ore, suffering from interlocked particles, is challenging for any process technology. Extensive grinding is required to attain liberation and to yield concentrates of desired grade. Fine particles are commonly very difficult to retrieve, resulting in value losses to tailings. In this paper, results from HGMS tests on fine to ultra fine hematite are reported. Special emphasis is put on slurry flow velocity. If hydrodynamic drag force, i.e. flow velocity is not controlled and kept constant during the feed and/or rinse phase, fine particles will not be captured and retained. Flow velocity control and constant flow during separation are achieved by discharge valves/slots and parallel magnetic flux and pulp flow configuration. In tests, increased slurry velocity from 178 to 268mm/s caused Fe-recovery to drop from 78 to 48%. Proving that flow velocity control is essential to optimise grade and recovery. HGMS tests at the Metso mineral laboratory on natural (weathered) hematite fines clearly show a large potential to recover valuables, currently lost to tailings. Even at particle size distributions as low as D80=35µm concentrate grades and recovery are very satisfying. Two samples, in-plant desliming rejects (D80=35µm and 50µm) where significantly upgraded and recovered, from 45,3% to 63,6% and 53,0% to 63,4% Fe, at 73,8% and 81,1% Fe-recovery respectively. Other types of in plant rejects, such as gravity separation or WHIMS tailings, also benefits from HGMS separation. Gravity separation reject, 55,8% Fe, at D80=500µm was tested, yielding a magnetic concentrate of 60,8% Fe at 50,7% Fe-recovery. The results indicated that the hematite was poorly liberated. HGMS separation was repeated after a regrind to D80 150µm, resulting in a magnetic concentrate of 62,8% Fe at 75,9% Fe-recovery. The tests prove that hematite, presently lost to tailings streams, can be recovered by HGMS and thereby significantly contribute to improved overall economy. Keywords: HGMS, magnetic separation, recovery of ultra-fine hematite, Indian hematite ores, hematite recovery from tailings

Sep 1, 2012

By Luis Fortunato Rioja

Southern Peru, es una empresa minera que explota cobre a Tajo Abierto, en cuyo proceso de explotación del mineral se utiliza un sistema mecánico manual de introducción de las barras de acero a los molinos que genera una serie de problemas como el mayor empleo de mano de obra, carguío mecánico manual, inseguridad y la elevada pérdida de producción anual. En ese sentido, el presente trabajo señala el uso del equipo “Fighter Bull" para introducir las barras al molino en el menor tiempo posible. El diseño de este equipo se desarrolló en los Talleres de Maestranza de Toquepala de nuestra empresa Southern Peru Copper Corporation y permite reducir en gran porcentaje las pérdidas de producción de molienda de mineral y no produce riesgos de accidentes de accidentes para los trabajadores.

Sep 19, 2006

By V. Aprahamian, G. B. Harris, C. W. White, M. Tangen

"In 2005, the Royal Canadian Mint (RCM) commissioned a new silver electrorefining circuit. This circuit was intended to operate with a minimal electrolyte bleed for the control of copper. However, by the time of start-up, the levels of copper-rich silver doré to electrorefining had increased, and despite partial pyro-conversion in a small Top Blown Rotary Converter (TBRC), copper concentration in the silver anode still averaged 7.5%. This necessitated frequent replenishment of the electrolyte with fresh silver nitrate since copper displaced dissolved silver during electrolysis, and therefore requiring a robust copper bleed treatment step in order to maintain cathode silver flake purity at 99.99%. The originally-installed bleed treatment system could not meet the RCM’s needs. A thorough review of known technologies, however, did not indicate one capable of handling the copper load, and resulted, therefore, in the development of a novel copper hydrolysis approach for removal of copper as an insoluble basic nitrate salt, and recovery of the associated nitric acid for re-use in the circuit. Laboratory-scale trials showed reproducible results, and existing equipment was subsequently modified.INTRODUCTIONIn 2005, the introduction of a new silver electrorefining circuit at the Royal Canadian Mint (RCM) initiated changes in the way customer silver, collected from the gold doré circuit, was processed. These circuit changes were discussed in a recent paper (Aprahamian, 2015). A wastewater treatment plant had not been budgeted at the time, and this represented a significant constraint when considering the introduction of a wet processing circuit. After a review of various options, a turnkey silver electrorefining circuit was purchased from a European firm. Initially, enough cells were ordered to produce 2 million oz of fine silver (999), with the option to increase to 5 million oz. The selected equipment was based on a Moebius cell design combined with a silver grain pressure dissolver to produce make-up silver nitrate solution. Additionally, an evaporator/hydrolysis unit included in the package appealed to the Mint Refinery, on the basis that it offered a simple way to bleed dissolved copper in electrolyte without generating effluent."

Jan 1, 2016

By J. T. YIi-Penttiia

Dust formation and reaction mechanisms of copper matte particles were investigated in simulated flash oxidation conditions. The granulated and ground matte consisted of 72 wt% Cu, 4 wt% Fe and 21 wt% S. Experiments were conducted by using a laminar-flow furnace with a reaction gas composition ranging from 20 vol% to 75 vol% O2 in nitrogen. The particle feeding was carried out by the single-particle method and samples were quenched after a specified reaction time (approximately 0.05-004 s) in a cold water film. Experimental temperatures were between 800 and 1300°C. Chemical analysis was used to determine oxidation degree, and an optical and scanning electron microscope combined with energy dispersive analysis was used for characterization of the reacted particles.

Jan 1, 1998

By D. Q. Li

"This paper briefly introduces problems that can occur in the design of rare earth separation processes and that require close attention during engineering design. Important factors must be considered include the following. 1) The separation process is primarily based on two points. One is the raw material composition and the other is the product purity requirements. 2) Optimization of the rare earth separation process requires optimization of the flowsheet configuration and each process parameter. 3) The separation of heavy rare earths is performed under non-equilibrium conditions. 4) The radioactive elements uranium and thorium must be removed from the feed to separation. 5) Process economy and environmental protection must be considered together in the evaluation of any separation technology options. INTRODUCTIONThe importance of rare earth (RE) is well recognized in high-tech applications and sophisticated national defense technologies. RE is the treasure house of the 21st Century new materials. The RE separation processes developed using HEHEHP (P507), P507-alcohol (ROH) and naphthenic acid (NA) have been widely applied in China. These processes have led to industrial production of all of the individual RE with up to 4N (99.99%) or higher purity (Li, Wan, Lin, Xie, Lin, & Wang, 1980; Li, Wang, & Xie, 1985; Li, 1995; Li, Wang, Meng, & Li, 2005). In order to achieve the best economic and environmental benefits, this paper discusses several problems to which attention must be paid in the design of rare earth separation process."

Jan 1, 2016

By Ying Qin, Shujing Zhu

The characterization of adsorption of natural and composite bentonite in lead aqueous solution has been studied. The results showed that adsorption of both natural and composite bentonites strongly depended on the pH values of the solution. At lower pH values, the mechanisms that govern the adsorption of bentonites were dissolution of crystal structure and competition between the metal ions and the H+. To composite bentonite, the lead ion removal capacity was close to 250 mg/g. At higher pH values, formation of lead hydroxyl species might lead to either participation to the adsorption or precipitation onto the bentonites. Hence, a rapid increase in the equilibrium removal capacity of lead was obtained when pH > 7.0. An increase in the initial lead ion concentration led to the increase in the equilibrium adsorption capacity increased to a certain degree; and then, a plateau was obtained at higher concentrations. As a result, the adsorption performance of composite bentonite was better than the natural bentonite in both physical and chemical changes. The data fitted well with both Langmuir and Freundlich isotherms.

Mar 1, 2017

By Riley S. J

The basic aim of mine planning is to design mine layouts and schedules that achieve optimisation of operations, minimum cost and maximum resource recovery. Successful accomplishment of this aim is facilitated by timely and comprehensive rehabilitation planning commencing at the pre-feasibility stage and continuing until the end of mining. Incorporation of a final landfomt design for waste rock dumps in a mine plan requires a prediction of surface stability, which may be achieved through erosion modelling. Erosion prediction models can be placed in two broad categories: soil loss prediction models eg USLE and CREAMS, and geomorphic models such as SIBERIA. A waste rock dump landform design based on selected slope form and grade and drainage systems should be developed as part of planning. A digital terrain model (DTM) of the landfonn should then be produced which can be modelled for long-term erosional stability using pre-determined parameter values. If acceptable standards of stability are not achieved, the landform should be redesigned and remodelled until the desired result is obtained. The planning process incorporating models requires knowledge of spoil or waste rock properties and model parameter values. This information is site specific and can be obtained from drill cores or costeans at the pre-mining stage and from spoil or waste rock during the mining stage. Realistic model parameter values are critical in post-mining landfonn design and can be obtained by several methods, including rainfall simulation, monitoring, geochemical analyses and grain size analysis.

Jan 1, 1994

By A. H. Bell

DEEPEST hole in the earth, and deepest producing oil well in the world-such is well No. K.C.L. A-2, of the Continental. Oil Co., completed on April 12 in the San Joaquin valley about four miles west of Wasco, Calif. It penetrated the earth's crust to a depth of 15,004 ft.- almost three miles-a depth that exceeds by over 2200 ft. that of the previous record holder in western Texas. It is now producing oil from sands at a depth from 13,092 to 13,- 175 ft., which is about 1500 ft. deeper than the record formerly achieved in Louisiana. Continental's new well was bottomed in what is possibly Domengine-Avenal Eocene sand, and is producing from the Middle Miocene equivalent to the Rio Bravo sand.

Jan 1, 1938

By W. E. Wrather

DURING the war the mineral industry, and metal mining in particular, extended itself more than any other to attain the limit of its productive capacity. Likewise, probably no other industry went quite so far toward jeop¬ardizing its own economic future through depletion of material reserves. Once we looked to Europe for most of the manufactured goods we needed. Our own limited mineral requirements were easily supplied from mines near the Eastern seaboard. With expansion and industrialization, our mineral needs increased in proportion, and the centers of mining activity moved westward to Michigan, Wisconsin, Minnesota, and the Tri-State district, where seemingly inexhaustible high-grade deposits of iron, copper, lead, and zinc ores were opened and rapidly developed.

Jan 1, 1946

By Eric J. Grimsey

Nickel smelting and converting can be viewed as processes in which iron is either partitioned or transported between matte and slag. Metal recovery depends on the mass of iron transported to slag, the thermodynamic environment in which the transport is made, and the extent to which the slag, once formed, is left in contact with the matte. The importance of these effects is discussed with reference to a new equation which describes metal recovery in terms of a mass balance and a thermodynamically related parameter which is easily measured in practice.

Jan 1, 1993

By Michael I. Morris

The U.S. Department of Energy's (DOE's) Transuranic and Mixed Waste Focus Area (TMFA), funded from fiscal year (FY) 1996 though FY 2002, was tasked with finding solutions for the mixed waste treatment problems of the DOE complex. During TMFA's initial technical baseline development process, three of the top four technology deficiencies identified were the need for amalgamation, stabilization, and separation/removal technologies for the treatment of mercury-contaminated mixed waste. The Mercury Working Group (HgWG), a selected group of representatives from DOE sites with significant mercury waste inventories, assisted TMFA in soliciting, identifying, initiating, and managing efforts to address these areas. Solicitations and contract awards were made to the private sector to demonstrate both the amalgamation and stabilization processes using actual mixed wastes. The goal was to develop separation and removal processes that will address DOE's needs. This paper discusses the technology selection process, development activities, and the accomplishments of TMF A through these various activities.

Jan 1, 2003

By J. S. Becker

Technology developed and first implemented in the United Kingdom enables very low grade aluminum scraps containing oils, organics, plastics and ferrous metals to be directly charged, without pretreatment, into a unique melting furnace. The system has been in full scale production for four years. The oxy-fuel-based furnace design incorporates internal afterburning in the furnace's hot zone, producing excellent thermal efficiency and very low emissions. The furnace is inherently low in NOx. This paper will provide both theoretical background and extensive operating results for this new melting concept. Applications describing both purpose built new furnaces and retrofits of existing reverberatory furnaces will be presented. Extensive operating emissions data will be presented.

Jan 1, 1997

By Phil Wilkinson, Sam Whitaker

"The installation of large (XL) diameter monopiles offshore typically requires expensive and specialist plant, equipment and vessels. Due to the increasing size (weight, diameter and length) of the foundations, in order to mitigate installation risk, the use of large diameter drills is becoming an increasing requirement.Project developers often try to avoid drilling operations due to the time associated with the drilling process. This restricts projects in terms of location and it also overlooks the additional engineering benefits drilling can bring to monopile foundation design e.g. reduced foundation material and better fatigue design life.By comparing the lessons learned of three milestone overwater drilling projects; methods of maximising drill speed and decreasing drilling process time is established. Particular emphasis is put on pile internal relief drilling in a process known as Drive-Drill-Drive (DDD).The milestone overwater drilling projects are North Hoyle Offshore Wind Farm (OWF) (2003); Flamanville EPR cooling water outlet shaft (2008); and Gwynt-y-Mor OWF (2014).By evaluating the effect of foundation pile diameter on drilling process times, example foundation installation costs are derived and used to show that incorporating drilling as part of a process may not be cost prohibitive to projectsContinued advances in drill technology, and drilling rates of penetration, combined with an integrated approach to foundation design, challenge whether hammering only is always the optimal solution for XL monopile installation."

Jan 1, 2017

By Emmanuel Henry

Hanging wall deformation monitoring at the Kiruna Mine is a major concern for Luossavaara- Kiirunavaara AB (LKAB) since underground production is deepening towards the Kiruna Town. In the quest for more effective monitoring techniques, LKAB decided to evaluate satellite-borne Synthetic Aperture Radar (SAR) interferometry?s ability to monitor ground subsidence by generating continuous deformation maps from satellite radar images. While adopted by other geoscience-related industries, SAR interferometry is still relatively untested in the Mining industry. This paper describes how subsidence is actually monitored on the Kiruna Mine?s hanging wall and gives an insight on SAR interferometry?s principle. The encouraging results are discussed as well as the technique?s benefits (continuous deformation mapping, low cost, fast, etc) and limitations (sensitivity to snow and vegetation cover).

May 1, 2003

By Ph. D. Favreau, Favreau Patrice B. Eng, R. F.

Geology is important in mining by helping to identify the rocks which contain sufficient valuable ore to justify their excavation. Geologists give a geological name to each rock type, so geology is a player in blasting; when a blaster has successfully blasted rock of a given geological name at a former site, and he later has to blast rock at another site whose rock has the same geological name, then his first trial often is the same method as he used at the former site, since the geological name of the rock is the same

Jan 1, 2019

By Albert Hill Fay

IN giving a sketch of the geology and mining of the tin-deposits of Cape Prince of Wales, a short description of the geographic and climatic conditions may be of special interest on account of this being a part of the world of which very little is known, even by the reading public. As shown in Fig. 1, the location of the Cape is lat. N. 65° 35' and long. W. 168°. It is bounded on the north by the Arctic ocean ; on the west by Bering strait and on the south by Bering sea. It is the western-most point of the mainland of North America, and to the west, across the strait, one can see East Cape, Siberia, which consists of a rugged, steep coast of granite cliffs. The climatic conditions are of interest because of the part they have had in the surface geology, and also because they affect mining from an economic standpoint. In connection with the climate and geography, it does not seem out of place here to quote a few lines from the prologue of The Wandering Jew, written by Eugene Sue, under the caption '1 The Land's End of Two Worlds."

Sep 1, 1907

By M. S. Shishvan, S. Klerkx, J. Sattarvand

The inaccurately drilled blastholes from the planned locations cause changes in the spatial distribution of explosive energy; some areas of the blast may receive a surplus of explosive energy, while others see a reduction. This results in less uniform fragmentation, reduces the efficiency of mining operations and increases costs. Additionally, it can lead to slope stability issues, flyrock, and uneven benches. To mitigate these problems, this study attempts to reduce differences in the explosive energy distribution (EED) through an optimization approach that adjusts the height of explosive columns in blastholes. Two optimization algorithms, the Genetic Algorithm (GA) and Tabu Search (TS), are tested. The latter is preferred for its local search neighbourhood strategy that gives superior computation times. Applications on different blast patterns result in improvements of 0.53–1.54%, or 2.14–3.94% when only the affected blocks are considered.

Sep 1, 2021