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By Yoshitaka Mitsuda, Masao Miyake, Masafumi Maeda

A leaching treatment was investigated to recover metals including rare earths from the mixtures of hydrogen storage alloys and nickel hydroxide. A potential-pH diagram of the La-Ni-H20 system including the domain of stability of LaNi5 was drawn to find appropriate leaching conditions. Alkaline solutions containing ligands that form complexes with nickel ions were supposed to be available to separate hydrogen storage alloys from the mixture. When the mixture was leached with ammoniacal alkaline aqueous solutions, the nickel hydroxide was dissolved and the hydrogen storage alloy was recovered as its original alloy.

Jan 1, 2004

By J. Jung, W. Keller, A. Zucht

"The agitator design for nickel high pressure acid leach autoclaves (HPAL) is critical with regard to the process result, i.e., the recovery rate. Further considerations during the design phase are the avoidance of acid hot spots which reduce the lifetime, due to corrosion of the wetted parts, including components manufactured from titanium. Besides the process knowledge to design HPAL autoclaves, tools such as, Computational Fluid Dynamics (CFD) supplemented by lab testing allow the design of optimized agitation systems. This paper describes the effect that different feed point locations have on instantaneous blending of the reactants. Furthermore, experiments and CFD show where abrasion issues might occur and how to obtain information about the static and dynamic forces acting on internals. We show how simulations can be validated by lab testing to ensure that the CFD models are applied in an appropriate way.INTRODUCTIONAgitated systems in hydrometallurgical processes have to comply with multiple process tasks and in many cases have to withstand extreme operation conditions such as pressure up to 50 bar, elevated temperatures of up to 250°C and exposure to very acidic or alkaline environments and abrasive ores. The process tasks range from instantaneous mixing of reactants, homogeneous suspensions of up to 65% wt. solids with coarse and heavy particles, enhancing the solid-liquid mass transfer for leaching, dispersing large volumes of reactants (gas-liquid, liquid-liquid mass transfer) and moreover to transport generated heat e.g., from exothermic reactions through the vessel walls or internal heat exchangers if required. For economies of scale, agitator systems have reached sizes of 5000 m³ for large open leach tanks with impeller diameters of approx. 6 m, while autoclaves nowadays have exceeded 5.5 meters in diameter with a power demand for a single compartment drive between 300 - 400 kW. In parallel all process industries require a more efficient use of resources, to generate less by-products and higher yields, while ore-bodies tend to be less qualitative and new process routes (e.g. direct leach) are developed. Besides all these facts the mixing solution must be robust and economic. In this paper we want to address our approach in the development and designing of HPAL agitation equipment."

Jan 1, 2012

By H. R. Oliveira, C. R. Aragonez de Vasconcellos

Pipeline operation and maintenance necessarily involves geotechnical studies at points and areas with deflagrated instabilities or still to map and monitor areas prone to geotechnical problems. Landslides, erosions and debris flows are some examples of natural hazards, that not rarely, can bring high consequences to pipelines, sometimes leading them to high stresses levels and ruptures. Bolivia-Brazil Natural Gas Pipeline has 2.593 kilometers since Rio Grande City in Bolivia until Canoas City, in south Brazil. The pipeline crosses a lot of types of geological fields and difficult topography. The south spread of the pipeline has the most prone areas to geotechnical hazards because of its hard topography combined with the variety of geological materials, such as, colluvium deposits and debris flow areas. The aim of this paper is to present the right-of-way geotechnical risks that affect pipelines, presenting some practical remedial works done by TBG at Bolivia-Brazil Natural Gas Pipeline as well as the integrity plan and the adopted actions in way to prevent geotechnical accidents.

Jan 1, 2005

By R. Burnette

Gold has been mined from a variety of deposit types that range in age from Archaean to Recent. The large variability in the geological settings of the gold deposits implies transport and concentration of gold by magnetic, hydrothermal and sedimentary processes. The factors that control the concentration of gold at certain sites and the grade estimation thereof remain major topics of debate. Due to the complex nature of the Witwatersrand Basin a mineralogical study, including mineralogical, petrographic and geochemical investigation was launched on TauTona Mine in order to characterize the various reef facies. The aim of the investigation was to determine if a correlation could be found between macroscopic characteristics of the reef, hanging wall and footwall, and the microscopic nature of the ore (especially gold grade). Petrograpgic and mineralogical results indicate that a correlation exist between gold, detrital and hydrothermal sulphides, uraninite, carbon, detrital heavyminerals and phyllosilicates. No correlation exist between gold and Mg, Fe or S. It appears that clast supported reef is of higher wade than matrix supported, but more work is suggested. No correlation exists between reef thickness and grade. The reef samples had the lowest phyllosilicate content compared to the hanging wall and footwall samples with pyrophyllite the most dominant. All of the correlations diagrams showed significant scatter and suggests a multi- factorial mineralization model. Gold distribution is also controlled by sedimentary features and thus it is not possible to select a single model for the formation and distribution of gold. It is evident that both sedimentary and hydrothermal factors influenced the mineralization and gold distribution on TauTona mine. It is thus essential that all related theories be incorporated in the development of a grade prediction model.

Jan 1, 2011

By M. Reda

Because of the adverse environmental effect of Chromate, Molybdate ions had been investigated as replacement for Chromate and the results had shown not to be encouraging. Film deposited from peroxopolymolybdate (from reaction of Molybdenum meta, with excess Hydrogen Peroxide), are more robust than that deposited from molybdate solutions. This was shown to be due to higher fraction of Mo (IV) and Mo (V) that form from Mo (VI) in the peroxopolymolybdate deposited film than the film deposited from Molybdate solutions. The peroxopolymolybdate film contains 40% un-hydrated molybdic acid, tetraperoxodimolybdate and tetra peroxo tetra molybdate. The protective properties of peroxopolymolybdate were shown to be due to the effectiveness of the un-hydrated molybdic acid.

Jan 1, 2010

By Douglas Brand

"The data that many mineral processing plants make use of, is provided by samples taken from sampling systems which are inadequately designed or improperly maintained, and therefore cause detrimental effects to plant operations, production planning and metallurgical accounting! Poorly designed or maintained sampling systems will likely produce low probability samples which give the operator a false sense of security of the product and the process. If data is the basis for action (Flintoff, 1992, p.2), then using the resulting suspect or bad assays by operators, control systems, or metallurgist and administration personnel will act and make decisions which may adversely affect the profitability of a processing plant. Here we will discuss some of the fundamental sampling problems, propagation of errors and a method to estimate what impact this has on an operations Net Smelter Return.INTRODUCTIONIn order to control a mineral processing plant at its best potential, it is necessary to obtain the best possible measurement results of the metal or mineral in question. The sample which is delivered to a measuring instrument, or lab, needs to be of the highest probability to be able to achieve this. This paper will discuss the effects of sampling errors on grade / recovery and grade / Net Smelter Return (NSR) and provide a method to estimate the monetary advantages of using probabilistic sampling in a processing plant.REVIEW OF SAMPLINGSampling, by definition, is the removal of a small representative portion from a total consignment, or flow, for the purpose of accounting or process control.• A sample can only be considered representative, if each and every increment collected, in each of the sampling stages, is representative.• Each particle of the sampling lot must have the same probability of being included in the final sample.• If both of the above conditions are met, then the final sample will be representative of the complete sampling lot.It is commonly known that in order to take truly representative and probabilistic sample, best practices indicate that:• The total stream should be sampled.• The sample cutter should intersect the sample at right angles to the flow.• The sample cutter should travel through the stream at a linear and constant speed and the speed deviations should be less than 5%."

Jan 1, 2016

By Fidelis T. Suorineni

Rapid drifting enables quicker access to orebodies, higher productivity rates and a resultant reduction in activity costs. Increased advance rates, by examination of the key components (face preparation and drilling, hole loading and blasting, scaling, mucking and support installation) in the development cycle, and optimizing these processes is a high priority for research in the Canadian mining industry. Support installation time alone is typically 36 to 46% of the total development cycle time. A reduction in support installation time or techniques and alternative scaling strategies could result in significant gains in drift development advance rates. Support Staging and hydroscaling within the drift cycle could offer alternative drift development sequences that could reduce the overall cycle time. MIRARCO?s research into the support and hydroscaling processes for rapid drift development also suggests that there are many other factors (e.g. mine ventilation services) that have a significant impact on the rate of advance. These factors should be considered to promote and manage safe and rapid drift development. Constraints to the rapid drift development processes can only be overcome by sound construction management practices. In other words, the goals of rapid drifting can be achieved by the implementation of contractor-type construction management. This paper examines various constraints and processes affecting rapid drift development and draws attention to other factors affecting safe rapid drift development.

Apr 1, 2005

By G. Binks

In 1997, the Zinifex Hobart Smelter ceased ocean disposal of jarosite and the flowsheet was converted to reject iron as paragoethite. This paper describes the evolution of the flowsheet since the changeover and considers future flowsheet developments. The major change to the flowsheet has been an increase in the silica content of the calcine resulting from treating increasing levels of Century concentrate. The high silica levels impacted on the paragoethite precipitation stage, causing a deterioration in the settling and filtration characteristics of the paragoethite and an increase in the contained zinc level. The implementation of a two stage neutral leach step has enabled the flowsheet to cope with the higher input silica levels. Future developments include an understanding of the form of the zinc in the paragoethite and options to lower the zinc level to improve the overall zinc recovery.

Jan 1, 2006

By L. Zeng, Q. Feng, Z. Qiu, L. Ou, Central South University

It is well-known that the use of nanobubbles can significantly improve the flotation efficiency of ultra-fine particles. However, this is mainly focused on coal and phosphate rock flotation. In the field of nonferrous metal processing, the related research is few. In this paper, a small laboratory mechanical cell associated with a specially-designed nanobubbles generator was used to investigate the effects of nanobubbles on enhancing ultra-fine scheelite flotation. Nanobubbles were created and based on the hydrodynamic cavitation principle through Venturi tubes. Comparative flotation tests were performed using different tubes to evaluate the nanobubbles impact on the ultra-fine scheelite particle flotation recovery. In order to better understand the nanobubbles enhanced ultra-fine scheelite flotation, nanobubbles potential and size distribution were measured. The effect of nanobubbles on the particle aggregation and scheelite particles potential were also studied through the turbidity tests, microscope tests and zeta potential measurements. According to the results, the mean size of nanobubbles was about several hundred nanometers, and the surface of nanobubbles was of highly negative charge in alkaline conditions. The flotation recovery of ultra-fine scheelite particles was increased in the presence of nanobubbles. The zeta potential measurements indicated that the repulsive forces between scheelite particles decreased when nanobubbles existed. Through the turbidity tests and microscope tests, the promotion effect of nanobubbles on particle coagulation could be verified more directly. The existence of nanobubbles in flotation system promotes the particle aggregation, thus increasing particles apparent size and particles capture by bubbles, which may be the fundamental reason why nanobubbles enhance ultra-fine scheelite flotation.

Jan 1, 2016

By T. Xue

429 As part of Inco's S02 abatement project for its Sudbury operations, a weak acid treatment plant (W ATP) was commissioned at the Copper Cliff smelter in August of 2004 to treat the weak acid streams generated by the flash furnaces, the MK reactor and the fluidized bed roaster (FBR) gas cleaning plants. The W ATP process was developed by Inco Technical Services Limited (ITSL) by means of laboratory and mini-pilot plant programs. In the W ATP process, the feed solution containing arsenic, sulphur dioxide, iron and other impurities is treated by oxidation and neutralization to form a stable precipitate for disposal in Inco's tailings impoundment area. During the commissioning of the WATP, a team of operations, maintenance, engineering, project and R&D personnel was formed, and the designed capacity was achieved in less than a month. Since then, the W A TP has been operating smoothly and the impurities, specifically arsenic, in the Copper Cliff smelting process have been effectively removed.

Jan 1, 2006

By G. Banini

Prior to installation of High Pressure Grinding Rolls (HPGR) at PT Freeport Indonesia (PT-FI) a series of laboratory tests were carried out to determine the design parameters and also determine key performance indicators (KPIs) for the industrial unit. The design parameters derived from the lab test work were then scaled up to estimate the industrial capacity of the HPGRs to be installed. These parameters include specific power draw, specific throughput, and specific force, rolls speed, product size distribution and wear rate of the rolls. This paper compares the performance of the scale-up procedure against the installed industrial size HPGR. Overall, the specific throughput of the industrial size HPGR is higher by a minimum of 30% compared to the expected scale-up value. As a result of the high specific throughput, the specific power draw and grind sizes are below the scale-up expectations in the commercial application. The impact of these factors also contribute to a lower than expected wear rate on the industrial rolls. Installed rolls achieved a service life in excess of 18,500 hours relative to the target of 6,850 hours predicted from the laboratory testing.

Jan 1, 2012

By W J. Riva

This paper reviews the coal mining operations of The Canmore Mines, Limited, at Canmore, Alberta, paying particular attention to the use of this coal by the metallurgical and chemical industries. The characteristics of the deposits are outlined, and the mining and processing methods used are discussed. Introduction M INING in the Cascade coal area of Alberta began form-ally in 1886 when the Canadian Anthracite Coal Company was granted its charter. Earlier operations had been confined to prospecting and family-type enterprises serving the market area within barging distance on the Bow river. From 1886 to 1964, seven mines were opened between Banff and Ribbon Creek; six of these have since been abandoned, leaving the B c 0 L. original tenant, under the name of The Canmore Mines, Limited, as the sole survivor. The town of Canmore, hub of the mining ventures, is located on the main line of the C.P.R. and on the Trans-Canada Highway, 67 rail miles west of Calgary and 57 4 miles east of Vancouver, as shown in Figure 1.

Jan 1, 1965

By David J. Kerr, Robert Mason

"From1927 to1989, the Hornemineproduced53.7 Mt of ore grading 6.1 g/t Au and 2.2% Cu from two large volcanogenic massive sulphide deposits composed primarily of pyrrhotite, pyrite and chalcopyrite. The ore bodies were hosted by a package of chlorite-sericitealtered epiclastic rhyolite tuffs which were deposited in a narrow palaeo-graben located on the flank of a major felsic volcanic centre. M ineralizingfluids percolated upward through the permeable footwall rocks and were further focussed along syn-volcanic, graben-bounding faults. Sulphides were deposited by a process of sub-seafloor replacement of the rhyolite tuffs.Gold-copper-(zinc) mineralization, including ore zones mined between 1985 and 1989 as the REMNOR ore zones, is present throughout the 900 m of felsic volcanic stratigraphy at the Horne. All the deposits were formed by syn-volcanic hydrothermal processes active during felsic volcanism. There is no evidence to indicate that any economic gold mineralization was introduced by a post-volcanic hydrothermal episode.RESUMEDe 1927 a1989, /amineHorneaproduit53.7 Mt de minerai avec une teneur de 6.1 g/t Au et 2.2% Cu provenant de deux grands amas de sulfures massifs volcanogeniques comprenant esentiellement de la pyrrhotite, de la pyrite et de /a chalcopyrite. Ces gites font partie d'une séquence de tufs rhyolitiques epiclastiques chloritises et sericitises qui ont ere déposes dans un paleo-graben étroit situe sur le flanc d' unimportant centre vo/caniquefelsique.Lesfluides mineralises ont circule de bas en haut a travers /es roches perméables sous-jacentes; ils ont été également canalises par les failles syn-volcaniques en bordure du graben. Les sulfures se sont déposes par remplacement des tufs rhyolitiques immédiatement et sous /e plancher océanique.Les zones minéralisées en or et cuivre (±zinc) - y compris celles qui ont ere exploitees au cours de l’opération Remnor (1985-1989) - se retrouvent, sans discontinuité, à travers les roches volcaniques felsiques dont l' epaisseur atteint 900 m. Ces gites se sont formes par le biais d' un processus hydrothermal qui ag issait pendant le volcanisme felsique. II n'y a aucune évidence de minéralisation aurifère d'importance économique qui soit postérieure a l' activité hydrothermale syn-volcanique."

Jan 1, 1990

By H. R. Stockford

"A pyroxenite-carbonatite complex containing extensive pyrochlore mineralization was discovered during January, 1966, within an exploratory license area held by Consolidated Morrison Explorations Limited. Located 32 miles south of Moosonee, Ontario, the deposit was found under 100 feet of glacial till and Paleozoic sedimentary cover using airborne and ground magnetometer surveys. Exploratory and detailed drilling, totalling 47,625 feet in 85 holes, was completed in outlining the deposit to a maximum depth of 900 feet. Pyrochlore reserves are estimated at 62,000,000 tons averaging 0.52 per cent Cb,05 to a depth of 825 feet. Included in this tonnage is a high-grade section containing 10,000 tons per vertical foot grading 0.82 per cent Cb20 5• The deposit is still open at depth and the intrusive complex has by no means been fully explored.The columbium (niobium) mineralization occurs in a lineated calcite-dolomite host rock which has been intruded along a fault zone within a northeast-trending granulite belt. Potassium-argon dating indicates an age of 1655 million years.Preliminary studies suggest that the complex was intruded in a series of pulses in the form of a partially crystallized mush. The James Bay intrusive is unusual in that it is linear in form and contains only two main rock types - p•yroxenite and carbonatite. Nepheline-bearing syenites and associated rocks are notably absent. Moreover, the pyrochlore is essentially non-radioactive and free from many of the impurities generally associated with other pyrochlores. A test shaft to investigate soil conditions and to provide a 250-ton bulk sample was completed during 1968. Subsequent pilot-plant operations indicate that good quality pyrochlore concelttrates can be produced from this deposit."

Jan 1, 1972

By S. Hosseinpour

Chromate conversion coatings (CCCs) are usually applied to these alloys to enhance their resistance to localized corrosion and to improve paint adhesion. The special properties of these coatings such as their low electrical contact resistance (ECR) make them suitable for satellites. This study is aimed to develop advanced CCCs with the proper appearance, morphologies and surface roughness and to evaluate their role on the ECR and thermo physical properties on hardened aluminium alloy of Alclad-7075-T6. Coating characterization was performed by means of scanning electron microscope (SEM) and atomic force microscope (AFM). ECR of coatings were measured by special laboratory designed instrument and a and c were measured by Emissometer and Reflectometer respectively. In addition, corrosion performance of the CCC-coated alloys was determined by 168 hr exposing to salt-spray testing in accordance with ASTM-B117. The results of accomplished experiments on the developed CCCs in this study have been agreeable concerning available acceptability criteria for satellite surfaces.

Jan 1, 2007

By F. Channier

The paper provides the most recent information on the construction of the AP60 phase 1 plant of Jonquiere which is due to be commissioned and started up in the first quarter of 2013. HSE management on site by RTA, and cooperation with local equipment manufacturers and contractors of the Saguenay-Lac Saint Jean region are highlighted in this section. The AP60 phase 1 Jonquiere plant aims to demonstrate of the AP60 technology at an industrial scale and allows the further developments of the AP60 cell. The advantages of the AP60 cell technology in terms of productivity, power consumption and environmental footprint are also briefly presented in the paper.

Jan 1, 2011

By M. Aushouri, S. H. Mansouri, N. Aminizadeh

A thermo-chemical model of the Peirce-Smith copper converter in blowing the copper stage has been developed to predict the molten temperature. The key assumption of the model was that white metal and gas phases in the converter were in thermal and chemical equilibrium. In this model, the chemical reaction of white metal and oxygen was accomplished completely. So long as sulfur existed in the bath, the generation of Cu2O was frozen. The reaction rate was considered to be constant and controlled by the reacted sulfur. The converter temperature was calculated by heat balances over time. The model was validated by a detailed comparison with measured industrial data. A good agreement was obtained. The converter temperature depended on process parameters such as oxygen efficiency, molten emissivity and oxygen enrichment.

Jan 1, 2007

By J. P. Grieco, F. W. Grieco

"Manufacturing of Jaw CrushersOriginIn 1858 Eli Whitney Blake invented the first successful mechanical rock breaker-the Blake-type jaw crusher. Blake adapted a mechanical principal, the powerful toggle linkage system used to transform rotating motion and energy into oscillating mot ion and tremendous compressive forces. Today these same principals apply and the basic Blake-type jaw crusher is one of the leading machines of its class for heavy duty primary crushing service.In 1881 Philetus W. Gates patented a design for a crusher, the forerunner of the modern gyratory crusher which dominated the field from the late 1800s to the early 1900s. In 1910 the largest gyratory crushers built had 48-inch openings. However, about this time the jaw crusher came to life when the Power and Mining Machinery Co. built an even larger sized opening crusher-a giant 84-inch by 60-inch jaw crusher for a trap rock quarry in Pennsylvania. A 24-inch gyratory crusher became the ideal sized secondary machine for this size jaw. From that time on jaw crushers were looked on favourably as primary breakers and lines were brought up to date to parallel the already developed gyratory lines.FunctionMost heavy duty Blake-type jaw crushers work basically the same way. They are ruggedly designed and capable of crushing material in some cases in excess of 80, 000 p.s.i. compressive strength. They are very simple machines with few moving part s and, with the exception of replacement of renewable parts, are relatively maintenance free. It is quite common to have these machines in product ion for 20 to 30 years. The following will de scribe how these machines work. Large-diameter high-inertia flywheels which are connected to the main eccentric shaft, rotate inside a connecting rod type mechanism called a Pitman. It transforms rotating motion into vertical oscillating motion. This vertical motion is in turn transformed into reciprocating mot ion by means of a system of 2 toggles, each connected to the Pitman. The rear toggle is connected to the fixed rear head, and the front toggle is connected to the swing jaw which is hinged at the top of the crusher. With each rotation of the eccentric shaft the swing jaw opens and closes on rock which is fed into the crusher chamber, crushing the rock in a series of bites. These bites, or strokes as the y are called, usually vary between 1/2 inch to 1 1/2 inch at speeds of 120 to 200 strokes per minute. The reduction ratio of feed input to discharge is usually about 8 to I. Output capacities can vary from 100 tons/hour to 1200 tons/hour depending on the size of machine and its discharge opening. Horsepower requirements can vary from 75 hp to 400 hp.The entire crusher chamber is lined with replaceable 14070 manganese steel liner plates. This material is ideally suited for the job since it hardens as it wears during crusher operation. Manganese is also used in the high wear areas at each end of the toggle plates."

Jan 1, 1985

By J. P. Grieco, F. W. Grieco

"Manufacturing of Jaw CrushersOriginIn 1858 Eli Whitney Blake invented the first successful mechanical rock breaker-the Blake-type jaw crusher. Blake adapted a mechanical principal, the powerful toggle linkage system used to transform rotating motion and energy into oscillating mot ion and tremendous compressive forces. Today these same principals apply and the basic Blake-type jaw crusher is one of the leading machines of its class for heavy duty primary crushing service.In 1881 Philetus W. Gates patented a design for a crusher, the forerunner of the modern gyratory crusher which dominated the field from the late 1800s to the early 1900s. In 1910 the largest gyratory crushers built had 48-inch openings. However, about this time the jaw crusher came to life when the Power and Mining Machinery Co. built an even larger sized opening crusher-a giant 84-inch by 60-inch jaw crusher for a trap rock quarry in Pennsylvania. A 24-inch gyratory crusher became the ideal sized secondary machine for this size jaw. From that time on jaw crushers were looked on favourably as primary breakers and lines were brought up to date to parallel the already developed gyratory lines.FunctionMost heavy duty Blake-type jaw crushers work basically the same way. They are ruggedly designed and capable of crushing material in some cases in excess of 80, 000 p.s.i. compressive strength. They are very simple machines with few moving part s and, with the exception of replacement of renewable parts, are relatively maintenance free. It is quite common to have these machines in product ion for 20 to 30 years. The following will de scribe how these machines work. Large-diameter high-inertia flywheels which are connected to the main eccentric shaft, rotate inside a connecting rod type mechanism called a Pitman. It transforms rotating motion into vertical oscillating motion. This vertical motion is in turn transformed into reciprocating mot ion by means of a system of 2 toggles, each connected to the Pitman. The rear toggle is connected to the fixed rear head, and the front toggle is connected to the swing jaw which is hinged at the top of the crusher. With each rotation of the eccentric shaft the swing jaw opens and closes on rock which is fed into the crusher chamber, crushing the rock in a series of bites. These bites, or strokes as the y are called, usually vary between 1/2 inch to 1 1/2 inch at speeds of 120 to 200 strokes per minute. The reduction ratio of feed input to discharge is usually about 8 to I. Output capacities can vary from 100 tons/hour to 1200 tons/hour depending on the size of machine and its discharge opening. Horsepower requirements can vary from 75 hp to 400 hp.The entire crusher chamber is lined with replaceable 14070 manganese steel liner plates. This material is ideally suited for the job since it hardens as it wears during crusher operation. Manganese is also used in the high wear areas at each end of the toggle plates."

Jan 1, 1985

By Vishal Shukla, Prateek Singh, D. P. Chakraborty

"Continuous thickening by an operation called sedimentation is the separation of suspended solid particles from a liquid stream by gravity settling. The primary purpose of thickening is to increase the solids concentration of the feed stream. High rate thickeners are designed specifically to maximise the flocculation efficiency. A detailed investigation has been carried out to understand the influence of ore type and operating parameters such as bed level, bed mass, rake arm torque and flocculent concentration on thickening operation. Tata steel’s Noamundi plant data shows that variation in ore type, and operating parameters are major contributors to fluctuation in thickener performance. A lot of research has been done earlier on thickening operation but effect of ore type and operating variables by using plant data was never touched before.In this context, the performance of thickener was evaluated by daily data to study the influence of ore type and operating variables on thickener operation. Investigation shows that friable ore % in feed mix is proportional to slime density because friable ore is porous & brittle in nature. As a result, friable ore generates more fines/ultrafine during communition process in wash plant. Increase in flocculant concentration and bed mass is showing a positive change on high rate thickener performance Investigation shows that optimum bed mass and flocculant concentration is required to achieve desired pulp density in thickener underflow at different feed pulp density (g/cc).INTRODUCTIONOver the years, Iron Ore Beneficiation at Tata Steel, Noamundi has seen varied changes. Depletion of high grade iron and with increasing iron ore throughputs coupled with lowering of the hard ore a subsequent increase in slime generation, slime management and clear water requirement for wet Plant has thrown up myriad challenges. To overcome these challenges, many improvements initiatives were taken by Tata Steel in last decade. One of the major changes is the recent High Rate Thickener commissioning at Tata Steel Noamundi to cater the high iron ore throughput requirement. Slime reporting to Thickener has increased from 1.4 MTPA 2.5 MTPA over the last few decades. The above changes further aggravate the poor settling and dewatering characteristics of the slurry which is being feed to HRT. Considering the above mentioned constraints and stringent environmental implication proper water management has become a major challenge to reckon with. The thickener is used to increase the concentration of the suspension by sedimentation, accompanied by the formation of a clear liquid. In most cases the concentration of the suspension is high and hindered settling takes place."

Jan 1, 2016