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By A. P. I. Popoola, T. J. Olaniyi, A. A. Adeleke

"A laboratory froth flotation experiment was conducted on a low-grade carbonatite copper ore sample obtained from Phalaborwa in the Limpopo province of South Africa. The sample was a homogenous hydrocyclone overflow which serves as the feed to the flotation cells at Palabora Mining Company (PMC). The sample has an average copper assay of 0.59% with predominant copper-bearing minerals being chalcopyrite, bornite and cubanite. The carbonatite nature of the ore comes from the high content of calcium (28.85%) and magnesium (6.84%) minerals. Collectors used were sodium diethyl dithiocarbamate and potassium ethyl xanthate alongside Senfroth 38 supplied by Senmin. The results showed that at 200 g/t mixture of collectors (50:50), an optimum grade of 8.03% Cu in the rougher flotation concentrate was achieved at 74% recovery, while during the second flotation, 24.65% Cu was obtained at 74.4% recovery using a Senfroth 38 dosage of 6 L/t with 100 g/t mixed (50:50) collectors. The particle size and pH value of the pulp played a significant role in that the mixed collectors performed efficiently at pH above 8.3 and at room temperature while particle sizes greater than 53 µm were well concentrated when compared with those of less than 53 µm. INTRODUCTION The need for copper ore concentration research is on the rise as a result of the depletion of deposits and the advent of low-grade copper ores. Although most copper ore deposits have other valuable minerals that support their economic extraction, the increase in technological innovations as regards copper usage and applications has increased the demand for copper. Several factors influence concentration results in a froth flotation column, of which the reagent used is most influential."

Jan 1, 2015

By Hal W. Hunt

Steel and concrete piles and power-actuated hammers have developed almost entirely within the past 100 years. Prior to that time, piles were mostly timber, driven with a drop hammer or a maul. The Engineering News Formula ? for timber piles driven with a drop hammer at a factor of safety of six ? was promulgated by Wellington in 1888. Steel com­panies supplied fabricated and rolled shapes for piles in the early 1900's. The thin shell and then uncased concrete piles originated about that time. Now leads have become sophisticated to accurately spot a pile at any required batter. Hammers have grown to phenomenal size and vibratories are being accepted at full value.

Jan 1, 1984

By P W Haines

The McArthur, Balma (new name) and Habgood Groups are thick (up to 4.5 km) correlative sequences of shallow water evaporitic carbonates, mudstones and sandstones that are exposed largely within the Batten, and southern and northern Walker Fault Zones (Batten and Walker Troughs) of the McArthur Basin respectively. Recent re-mapping of the Walker Fault Zone has provided data for refined stratigraphic correlations between these groups. Two significant hiatuses are now recognised within the Balma Group (base of Vaughton Siltstone and base of Yarrawirrie Formation) and these may represent tectonically-generated sequence boundaries which may correlate with similar local hiatuses within the McArthur Group such as at the base of the Teena Dolomite and Lynott Formation respectively.

Jan 1, 1994

By W. G. SWART

THE best estimate on reserves of iron ore in the Lake Superior district is that made, in 1920, by Mr. R. C. Allen, amounting to 2,947,225,000 tons of assured and probable ore. This includes direct- shipping or so-called merchantable ores, and those capable of beneficiation by demonstrated processes. De- ducting from this the 287,000,000 tons shipped since 1920, leaves a present reserve of approximately 2,500,- 000,000 tons, or; about 50 years' supply. The assured ore in this estimate is given as 1,560,500,000 tons, which checks Mr. Lake's estimate of 1,528,948,000 tons, or about 30 years' supply. This is not a long time in the life of the steel industry, and it can be readily appreciated that the matter is important enough to war- rant the attention it is beginning to receive. The first question that engages our attention is, What is merchantable ore? In 1902 the average of all Mesabi shipments was 56.07 per cent iron and 4.35 per cent silica. Twenty-five years later it had dropped to 51.99 per cent iron, with silica up to 7.92 per cent. It has remained around these figures for' ten or twelve years and, except for a probable rise in silica, can stay there for an indefinite period. Most of these figures I am giving cover the Mesabi Range. Including the other ranges does not change the figures greatly, and the Mesabi Range commands the situation, since it produces about 65 per cent of the total annual tonnage and, according to Mr. Allen, contains 81 per cent of the assured reserves, 50 per cent of the probable reserves, and 66 per cent of both the assured and the probable reserves.

Jan 1, 1926

By Regina Krachler, Herbert Ipser

"The principles of the derivation of statistical-thermodynamic models to interpret the compositional variation of thermodynamic properties in non-stoichiometric intermetallic compounds are discussed. Two types of models are distinguished: the Bragg-Williams type, where the total energy of the crystal is taken as the sum of the interaction energies of all nearest-neighbor pairs of atoms, and the Wagner-Schottky type, where the internal energy, the volume, and the vibrational entropy of the crystal are assumed to be linear functions of the numbers of atoms or vacancies on the different sublattices.A Wagner-Schottky type model is used for the description of two examples with different crystal structures:For B'-FeAl (with B2-structure) defect concentrations and their variation with composition are derived from the results of measurements of the aluminum vapor pressure; the resulting values are compared with results of other independent experimental methods.For Rh3~ (with an NiAs-derivative structure) the defect mechanism responsible for nonstoichiometry is worked out by application of a theoretical model to the results of tellurium vapor pressure measurements. In addition it is shown that the shape of the activity curve indicates a certain sequence of superstructures.In principle, there are no limitations to the application of statistical thermodynamics to experimental thermodynamic data as long as these are available with sufficient accuracy, and as long as it is ensured that the distribution of the point defects is truly random, i.e. that there are no aggregates of defects."

Jan 1, 1996

By A P. Powell

This paper deals with the power plant at Cassiar Asbestos Corporation Ltd., Cassiar, B.C. It discusses the units installed in the plant, the distribution of power and the costs involved. The efficiencies and economics of this power plant are considered to be somewhat better than average. Introduction C ASSIAR Asbestos Corporation's power plant had its inception in 1952 with a 15-by 15-ft. log cabin containing two International Harvester diesel generator sets of 50 kw. total generating capacity. Over the years, it has grown to its present size -an 80 by 82 ft. by 35-ft.-high rigid-frame Butler building housing eight 2,300-volt diesel generating sets, a 2,300-volt distributing switchboard, a 550-volt auxiliary panel, three air compressors, six heat exchangers and other related equipment. The units in the power plant, numbered according to their order of placement, are rated as shown in Table I. The total generating capacity of the plant is 3,673 kw. All of the generators are of the open vertical design except that on No. 7 engine,

Jan 1, 1965

By Henry M. Howe

A discussion of the paper published in Bi-Monthly Bulletin, No. 20, March, 1908, pp. 227 to 237, and No. 22, July, 1908, pp. 615 to 620. PROF. HENRY M. HOWE, New York, N. Y. (communication to the Secretary *) :-Mr. Hibbard's definition of steel would be the best yet offered were it not for its one defect, the vagueness or equivocalness of "fusion-process." Puddling is surely in one sense a fusion-process, and so are the charcoal-hearth or knobbling-processes. But what he says suggests the following definition, which seems to me a good one: " Steel: any variety of iron which is usefully malleable at least at some one temperature, and is either cast when molten into a malleable mass, or if not so cast can be much hardened by sudden cooling." It is not necessary in a definition that quantitative bounds should be set up, for instance, that the exact height at which dwarf apple-trees cease and standards begin, or at which hills cease and mountains begin, should be stated. These quantitative measures are proper for specifications and contracts, but are not necessary for purposes such as the present. HENRY D. HIBBARD, Plainfield, N. J. (communication to the Secretary t) :-Professor Howe's criticisms of my definition of steel are not, it seems to me, well founded, for the . following reasons: The term "fusion-process" has been used during the past quarter or half century to distinguish the crucible, Bessemer and Siemens-Martin processes from the puddling- and cementation-processes, and probably no one at all conversant with the art of iron-metallurgy would now mistake its meaning. Moreover, no steel-metallurgist is in doubt of the meaning of the term "hardened? as applied to steel. If it were really necessary to describe what is meant by the term then it would

Nov 1, 1908

By H. L. Barr

THE following report covers the history of the development of the mine, present equipment, methods and costs of mining and milling. In addition, a description of the ore deposit is given with emphasis on the origin of the fractures, mode and types of ore occurrence, and mechanics of granite emplacement. An endeavor has been made to present a complete and accurate statement of the San Mauricio mine, the highest grade gold mine in the Philippine Islands. Credit is gratefully acknowledged to the mine staff for descriptions and details regarding their particular field of work. All analyses were made by Mr. T. A. DeVore, head chemist, San Mauricio Mining Co. Messrs. Edward Wisser, J. E. Fyfe, A. F. Skerl and W. B. Meek, geol-ogists, have contributed geologic information and ideas, for which thanks are extended. The Executive Committee of Marsman and Co., Inc., Managers of the Company, has kindly given permission for publication. Mr. J. B. Stapler, Division Manager, Marsman and Co., has had the courtesy to read the manuscript and to give critical and helpful suggestions.

Jan 1, 1940

Following is the personnel of the various society and national committees on which the A I M E is officially represented United Engineering Society Officers of the Board, 1920 JOHN VIPOND DAVIES,, President CALVERT TOWNLEY, 1st Vice-president ALFRED D FLINN,, Secretary WALTER M McFARLAND, 2d Vice-president JOSEPH STRUTHERS, Treasurer Finance Committee House Committee WALTER M McFARLAND Chairman GEORGE H PEGRAM W L SAUNDERS

Jan 1, 1923

By S. S. Klima, J. A. Organiscak

Researchers at the National Institute for Occupational Safety and Health (NIOSH) performed laboratory testing to examine and improve airborne dust capture and methane removal performance of flooded-bed scrubbers on continuous mining machines using a blowing face ventilation configuration to reduce respirable dust exposure to shuttle car operators. Several testing conditions were examined to minimize shuttle car operator dust exposure without adversely affecting continuous miner performance and production. Curtain-to-face setback distance of 9.1 m versus 15.2 m (30 ft versus 50 ft), face ventilation airflow of 226.5 m3/min versus 339.8 m3/min (8,000 ft3/min versus 12,000 ft3/min), and the use of side-body-mounted blocking sprays (on versus off) were the three primary parameters compared. Scrubber airflow was set and maintained at 198.2 m3/min (7,000 ft3/min) throughout testing. An examination of slab cuts versus box cuts and the location of the shuttle car (present behind the continuous miner versus not present in the entry) was also performed to demonstrate the effects of these constantly changing scenarios on scrubber performance. Results show that the best blowing face ventilation setup for minimizing shuttle car operator dust exposure for the tested parameters uses a 15.2-m (50-ft) curtain-to-face setback with 339.8 m3/min (12,000 ft3/min) face ventilation while operating the side-body-mounted blocking sprays. INTRODUCTION Coal mine worker overexposure to respirable coal dust continues to be a problem in U.S. underground coal mining operations, potentially leading to coal workers’ pneumoconiosis (black lung). The U.S. Mine Safety and Health Administration (MSHA) requires that respirable dust exposure to coal mine workers does not exceed a 1.5 mg/m3 average over the actual working shift (79 Fed. Reg. 24814 (2014)). Although using a blowing face ventilation configuration on continuous miner (CM) sections is beneficial for removing methane emissions from the mining face, it can be detrimental for dust control for shuttle car (or ram car) operators and any other workers on the return ventilation side of the CM when compared to exhausting ventilation. Even with machine-mounted scrubbers on CMs, shuttle car operators still have some of the higher dust exposures with blowing face ventilation systems (NIOSH 2011, Beck et al. 2015). Although scrubber discharge air is not completely clean, dust being blown around the scrubber inlet and therefore not being captured by the scrubber can further increase these dust exposures (Goodman 2000). Dust control problems are also caused by inadequate face ventilation quantities causing scrubber face airflow recirculation issues (Schultz et al. 2010). In order to minimize respirable dust exposures on blowing face ventilation sections, ventilation, water spray, and scrubber parameters were experimentally examined to improve operating ranges for both dust and gas control. Several blowing face ventilation factors were examined with respect to CM spray systems and scrubber operation. Curtain-to-face setback distance and side-body-mounted blocking sprays were previously examined in the laboratory for dust control on a full-scale CM model using a scrubber on a blowing face ventilation system (Goodman 2000). The blocking sprays produced larger dust reductions at the CM’s rear corners and return for a 6.1-m (20-ft) curtain setback distance as compared to a 12.2-m (40-ft) curtain setback distance with equal face and scrubber airflows of 169.9 m3/min (6,000 ft3/min). Because face ventilation airflow quantities, shuttle car operator locations, and tracer gas concentration gradients were not previously examined during these experiments, additional research was required to determine improved operating parameters for blowing face ventilation systems.

Jan 1, 2019

By Rudolf Voigt

Lignite reserves occur all over the world in different climatic regions. This means, that the impact of the hydrologic regime upon mining activities and, vice versa, of the mining activities upon ground and surface water conditions will be different between any two mines. On the other hand, most economically important lignite deposits can be grouped according to principal depositional and structural features described briefly in the following section. These features do allow a preliminary assessments of the nature of ground water problems which may face the mine. The cost of protection against water which threatens a mine, the environmental impact of the appropriate measures to achieve this end and the restraints of population density which both might exclude the most cost-effective approach will govern the project expenditure for drainage work. Whether or not this expenditure can be borne by the project must be established during the feasi¬bility phases of mine planning. So, the somewhat provoking title of this paper does not mean that its question can be answered once for ever. It should rather serve to bring to the attention of the audience the major features of mine water control.

Jan 1, 1985

By Howard L. Hartman

In 1969, the OECD conducted a survey internationally to determine the status and needs for research and development in the field of tunneling. The findings also have some validity for underground excavation in general and for underground mining per se. Of the 17 countries responding to the survey, the U.S. leads in the level of support: $21.8 million and 720 man-years of effort over the last ten-year period. The total volume of R/D for the 17 countries was estimated to be $86 million and 5800 man-years. Performance of research was primarily by government agencies and public utilities (70%); the balance was conducted by private organizations and universities (15% each). In the categories of R/D subjects surveyed, three--Wk mechanics, soil mechanics, and geological exploration--outstripped all the rest in priority of effort to date. Ground support, equipment development, excavation, and environmental control received intermediate attention. The subject areas in which the least R/D effort has been expended are materials handling and systems evaluation. For the future, those R/D areas rated the most crucial to achieve technological progress in tunneling were excavation, ground support, and materials handling. The survey findings of tunneling activity indicated (1) a disturbingly low level of R/D activity in the private sector, (2) the necessity for a reordering of priorities in directing research efforts in the future, and (3) a lack of recognition to date of the importance of systems evaluation in R/D activities.

Jan 1, 1970

Xstrata CopperÆs Mount Isa Copper Operations is located in mineral rich north-west Queensland and is one of the largest sources of copper in the world. This world-class underground operation is planned to produce over 6.6 million tonnes of copper ore in 2007 from the X41 and Enterprise Mines. With an underground mining history of over 50 years and underground reserves of over 83 million tonnes at 2.6 per cent copper, mine planning for the future becomes an exciting challenge for the technical team due to the older nature of certain areas. The 1100 Orebody of the X41 mine was one of the first places that copper mining occurred, with its discovery in 1953 - 1954 and mining commencing in the 1960s. Sublevel open stoping mining methods have been employed since that time as the means of extraction, using a primary-secondary sequence to maximise stope turnaround time. Large Transverse Pillars within the 1100 orebody were not mined out in order to provide access for ventilation, power, orepasses and other services. The Panel Pillar, 4180XC and 4010XC pillars are three such Transverse Pillars in the 1100 orebody that will be mined as a final retreat. This paper discusses the technical challenges and issues associated with the extraction of Q390 stope, one of the stopes located in the Panel Pillar, and the design solutions to overcome these issues. Managing the exposure of backfilled stopes of variable fill strength, ensuring the stability of the crown, stope walls and drawpoints, managing vertical openings, re-establishing service networks, and stope filling are the critical issues given consideration for the final design of Q390 stope and other such stopes within a Transverse Pillar. Communication and coordination between the different departments in the mine are essential for the necessary work to be completed in a timely manner to bring pillar stopes into production.

Jan 1, 2007

By Mario Dobrilovic, Zvonimir Ester, Vinko Skrlec, Vjecislav Bohanek

The first public garage in the city of Dubrovnik has been built in highly urbanized area, on location Ilina Glavica. The excavation of the building pit has been done partly by construction machinery, i.e. by hydraulic hammer for excavations and partly by drilling and blasting. In the vicinity of the building pit there are houses, buildings and two schools. Drilling operations and blasting have been performed during the working hours while regular school classes have been held and activities in other buildings took place. The nearest structures are some 5 to 10 meters (16.4 to 32.8 ft) away from the building pit, which makes it even more difficult to perform blasting operations in the urban environment. For the purpose of determining safe and permissible oscillation velocity limits, i.e. the proportion of seismic effects of blasting, a trial blasting has been conducted. The permissible mass of explosive charge has been determined by original method respecting the requirements of existing standards (ISO 4866, DIN 4150, US BM 8507), which determine the permissible oscillation velocities in relation to their frequencies. According to measuring results of the oscillation velocity during the test blasting the design parameters of blasting field have been corrected and zones have been established within the excavation area considering the possible effect of blasting to the building pit environment. Further blasting operations have been performed in stages, in smaller blasting fields with deck charge within a blast hole while respecting the requirements of the transport possibilities for the blasted rock mass within the building pit and performance of control measurements of oscillation velocity for each blasting. Through application of all the protection measures, design solutions and systematic control of performance of activities the complete excavation by blasting has been completed without any damage on neighboring structures/buildings. This article presents these solutions and methods for reduction of seismic impact of blasting to the environment.

Jan 1, 2009

By Suguru Kohno, Yoshihiro Momose, Masakazu Honma, Tokirou Kamosawa

Copper metal surfaces have been examined by an extremely sensitive surface analysis technique called temperature programmed photoelectron emission (TPPE). The surfaces were ultrasonically cleaned and subsequently abraded by a screw in organic solvents and water. The TPPE apparatus is composed of a Geiger counter with Q gas (He+ iso-C4H10). The curve of photoelectron emission (PE) intensity vs. wavelength from 300 to 170 nm, termed PE spectrum, was repeatedly measured at different temperatures in the temperature- increase process from 25 to 350°C. The number of emitted electrons in a PE spectrum (PE total count) increased, reached a maximum at-250°C, and decreased with increasing temperature. With the surfaces cleaned alone in the liquids the maximum PE total count decreased in the order C3H70H > (CH3) 2CHOH > C2HpH > CHPH > H2O. With the mechanically abraded surfaces in the liquids the maximum PE total count changed as a function of the abrasion period and the maximum tended to appear at higher temperature with increasing abrasion period; the maximum value at 10-min abrasion decreased in the order H2O > CHpH > C2HPH > (CH3) 2CHOH > n-C3HpH. It was suggested that the TPPE behavior can be related to the acid-base interaction between the alcohols and the abraded metal surfaces and the presence of a contaminant over layer on the surface. From the XPS analysis of the 01 s spectra it was suggested that the chemical change of the adsorbed oxygen to oxide oxygen with temperature plays a substantial role in the appearance of the maximum PE total count.

Jan 1, 2000

By G. S. Adisoma, J. J. K. Daemen, R. O. Roko

A common assumption in determining the shear strength of a rock joint using a direct shear test is that the surfaces undergoing relative shear are in complete contact. Furthermore, the limiting displacement associated with the residual strength values is obtained based on engineering judgement through visual inspection of shear force versus displacement curves. This study proposes a systematic way of determining the residual shear strength of rock joints by evaluating the limiting displacement leading to a minimum cohesive strength value and taking the true area of contact into account. The results of the study indicate that there is a limiting displacement associated with the residual shear strength, and some rocks may have an inherent interface residual cohesive strength different from zero. When the cohesion is different from zero, the residual shear strength is likely to be underestimated if the true area of contact is not considered. In the case where zero calculated cohesion is obtained, the area of contact has no bearing on the shear strength equation because the frictional force depends only on the normal load.

Jan 1, 1986

By P. Eger, D. Green

"The Soudan Mine was Minnesota’s first iron mine, operating from 1882 to 1962. The mine was donated to the State of Minnesota in 1963 and became a state park in 1965. The mine discharge contains elevated copper and cobalt concentrations and has been treated with an ion-exchange-resin-based system since 2009. The system includes flow equalization tanks, bag and cartridge filters, a carbon tank and two commercial ion exchange tanks. Although effective, the system’s high cost, inefficient removal of suspended material and substantial maintenance have been ongoing and troublesome issues.In November 2012, we initiated a pilot test using a peat-based sorption media. This media is produced from raw reed-sedge peat through a patented, low-temperature carbonization process that produces a hardened granular sorption material. The granules are uniform, have high hydraulic conductivity and maintain the high metal affinity of natural peat.Mine water was pumped through the peat-based sorption media without any pretreatment. Copper input concentrations typically ranged from 30 to 60 µg/L but increased to a high of 364 µg/L in the summer of 2013. Since startup, more than 60 million L (16 million gal or 32,000 bed volumes) have been treated, with average removal rates of 75 percent for particulate copper and 60 percent for dissolved copper. Backwash is required at about 4,000 bed volumes, but with a combination of air sparging and high-flow backwash, the suspended material is removedfrom the media.One tank of the peat-based sorption media was found to remove copper similarly to the first four components of the existing system. By reducing size and complexity, reductions in operation and maintenance costs are possible. A comparison of the estimated costs indicate that replacing the four initial components with the single media tank has the potential to reduce annual operating costs by more than half from around $163,000 to $70,000."

Jan 1, 2015

By Serge Ouellet

Résumé Six modèles métriques de remblai cimenté en pâte (RCP) ont été suivis durant 120 jours par l?utilisation de deux méthodes géophysiques non-destructives : la résistivité et la micro-sismique. Les RCP étaient constitués de trois résidus miniers et de deux proportions de ciment (3% et 6% en poids). En parallèle, des cylindres de RCP étaient utilisés pour évaluer périodiquement l?UCS. La résistivité augmentait quasi-linéairement de 28 à 120 jours pour tous les RCP investigués. Des variations de résistivité selon le type de résidu et le pourcentage de ciment ont été observées. Une équation empirique a été dégagée entre l?UCS, la résistivité, le temps, la densité relative et le rapport eau/ciment (E/C). La mesure de la vitesse des ondes de cisaillement a permis de dégager une équation mathématique de type exponentielle qui relie la résistance mécanique sans correction préalable par les paramètres de la recette de RCP. La réalisation de ce projet avait pour but de dégager la meilleure approche non-destructive afin d?estimer la résistance mécanique des remblais en chantier minier. Sur la base des résultats obtenus, les deux méthodes utilisées ont donné des résultats probants afin d?estimer la résistance mécanique et les deux méthodes sont donc à même d?être utilisées en chantier souterrain. Abstract Six scale models of cemented paste backfill (CPB) were followed during a 120 days period using two nondestructive geophysical methods: resistivity and micro-seismic. CPB were made up of three mine tailings and two cement proportion (3% and 6% by weight). In parallel, CPB cylinders were used to periodically evaluate uniaxial compressive strength (UCS). Resistivity was increasing nearly in straight line from day 28 to day 120 for all CPB models. According to the tailing type and cement percentage, resistivity variations were observed. An empirical equation emerged from UCS, resistivity, time, specific gravity of tailings and, water/cement ratio. The use of shearwave velocity allowed to identify a mathematical exponential equation related to mechanical strength without prior correction of the CPB?s formula parameters. The purpose of this project was to identify the best non-destructive approach in order to evaluate the mechanical strength of backfill in a mine site. On the basis of those results, both methods gave conclusive results in order to estimate mechanical strength and both methods can be used in underground operations.

Feb 1, 2008

By E. O. Wagner, Manuel Gomez, W. S. Landers

The Bureau of Mines studied coking rates of a special Columbia - Geneva six - coal blend to establish the effect of the coking rate on coke properties . The tests were conducted in a 500 - lb , 14 - in experimental slot oven at essentially constant conditions of blend composition , size distribution , surface moisture content , and bulk density . The coking rate was varied as a function of oven flue temperature . Coking rates within the range of 0.56 to 1.35 in/hr were achieved . Increase in the coking rate decreased the size of the coke . The stability factor of the coke showed no significant change with coking rate until coking rates greater than 1.0 in/hr were reached , after which a decrease in the stability factor was observed . The apparent specific gravity increased to a maximum value at coking rates approaching 1.1 in/hr and decreased sharply with further increase in the coking rate . Coke parameters correlated well with the coking rate .

Jan 1, 1963

By Chinmay Shingote, Robert Visintainer, Renjie Ke, Jaikrishnan R. Kadambi, John Furlan

Hydrocyclone separators are widely used in various industrial applications in the oil and mining industries to sort, classify, and separate solid particles or liquid droplets within liquid suspensions, which are considered to be multiphase systems. Numerous valuable studies have been conducted in recent years to investigate the flow fields inside hydrocyclones. However, much of the information regarding the performance of cyclones in the literature has limitations and much of it cannot be considered as completely applicable to most real-world applications; many of the studies investigated the flow fields within extremely simplified hydraulic designs that are not representative of the complex geometries or large sizes which are typical in industry. Therefore, in this study, the two-phase flow system inside the actual hydraulic geometry of a milling circuit hydrocyclone is explored with the aid of both computational and experimental techniques (particle image velocimetry (PIV)). More specifically, the flow field with an air core has been investigated. In addition, the air-liquid two phases flow in a hydrocyclone might cause some challenges on both the computational and experimental sides. Two turbulence models are utilized in the numerical calculations: the Reynolds stress model and large eddy simulation. The computational studies are mainly focused on the local flow behavior and the prediction of the dimensions and shape of the air core. Different section planes of hydrocyclone are selected as planes of interest and divided into several fields of view (FOV) for PIV measurements. Two-dimensional experimental velocity vector maps are obtained in each of the fields of view. The computational results are validated globally using pressure and flow rate readings at the boundaries and locally by comparison to the PIV velocity vector maps and profiles.