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By and Z. S. Abisheva, Z. B. Karshigina, Ye. G. Bochevskay, A. S. Sharipova

The production of precipitated silica in the United States is about 145,000 tons of SiO2 and its prices vary significantly (from $ 1 to $ 4.5 per kg) depending on the area of its application. One of the most important parameters is its specific surface characterising dispersion (particle size and shape, presence or absence of pores), at a certain value of which the material acquires new properties and quality. At present, a technology has been developed for processing slag from phosphorus production to produce precipitated silica (‘white soot’) with a high specific surface and the possibility of extracting valuable components such as rare-earth metals (REMs) into a product enriched with them has been shown. However, the content of impurities in the deposited silicon dioxide, such as aluminum and iron, is above acceptable limits and may affect the quality of the final products. Therefore, along with the structure and specific surface, a very important characteristic of ‘white soot’ is the chemical purity of the material. In turn, calcium oxide occupies a significant share in the concentrate of rare-earth metals, which affects the content of ΣREMs oxides, which does not exceed 17.3 %. The low content of a valuable component may affect the feasibility of further processing. For the most complete utilisation of phosphorus slag, the authors propose a method for their acid processing, which allows for minimising the conversion of impurities to finely divided silica and collective concentrate, which will improve the quality of these products. Keywords: Phosphorus slag, precipitated silicon dioxide, rare earth metals, leaching, white soot, specific surface, technology

Jan 1, 2020

By A. S. Nhleko, P. R. Lobe, H. Mtegha

"Government’s equity role in the minerals sector is one of the nationalist measures implemented in order to ensure greater control and management of a country’s mineral resources. This paper evaluates the Tanzanian government’s equity participation in the minerals sector from 1996 to 2015. The research methodology included determination of the number of mineral rights, minimum allowable exploration expenditures in prospecting licences (PLs), and forms of equity role of the government. Data was collected and analysed for PLs, mining licences (MLs), and special mining licences (SMLs).The study revealed a number of challenges faced by the Tanzanian government as regards its equity strategy in the mineral sector. One of the major challenges was the secrecy surrounding agreements and contracts entered into between the government and private sector investors, which were concluded via various business ownership and mineral development projects. This secrecy resulted in non-transparency and lack ofaccountability in the mining industry.The financial benefits accruing to the government were inadequately realized, evident through inconsistent payments of corporate income tax and mining royalties by the mining companies. Furthermore, the government does not have solid mechanisms and frameworks for assessing non-financial benefits, thus it is difficult to measure the impact of these factors.It is recommended that the Tanzanian government review the Mining Act and Regulations of 2010 to include the provision of solid mechanisms and frameworks for all forms of government equity role.This paper is based on an MSc research study undertaken at the University of the Witwatersrand.IntroductionGovernments can grant private companies mining rights to extract mineral resources, or take a stake in the companies as well as establish state companies to oversee their interests in the minerals sector. The establishment of a state company to oversee government interests in the mining sector implies the direct participation of government by way of equity participation. Equity participation or role is defined as the holding of shares in an enterprise, company, or asset by individuals or a body corporate (Otto, n.d.; Brown, 2013; Natural Resource Governance Institute, 2015)."

Mar 1, 2019

By J. H. Bulloch

A study of fatigue-crack growth in a rail steel and an associated weld metal showed that fatigue cracks in the deformed rail steel had slightly higher growth rates than in undeformed rail steel. The crack growth in the weld metal was appreciably faster than either and exhibited plateaux that were above the upper bound reported for rail steels, The cyclic-life curves showed that, over an indicated service period of 8 years, both the deformed and the undeformed rail steels should not be prone to fatigue failures under the defined mechanical conditions, For the weld metal, the cyclic-life curves indicated the possibility of premature fatigue failures but, as al the input parameters represented a 'worst case' situation, this assessment could wel be ultra-conservative. In the rail steels at low levels, the extension of the fatigue cracks occurred by ductile striated growth. At a Kmax level of 35 MPa .J/n, cleavage facets formed initially on the surface of the fatigue fractures, and their incidence increased with Kmax until the onset of fast failure, The microstructure of the deformed rail steel exhibited cleavage facets at a slightly lower Kmaxvalue, and contained more cleavage facets at a given K level, than the microstructure of the undeformed rail steel. The average size of the cleavage facets agreed well with the pearlite nodule dimensions of 60 to 100 ILm. The microstructure of the weld metal was much coarser and contained columnar grains. At al f.K levels, the dominant fracture mode was cleavage, with small isolated regions of ductile striated fatigue cracks. The size of the cleavage facets varied from 150 to 600 ILm, and such a variation may be explained by the fact that cracking generally occurs in association with the pro-eutectoid ferite phase, and that this phase is distributed along some boundaries of prior austenite grains and the boundaries of the coarser columnar grains.

Jan 1, 1987

By I. Satola, J. Aromaa

In this work we have reviewed methods to classify corrosivity of ground waters. Weight loss and stress corrosion cracking (SCC) corrosion tests have been done for rebar and steel strand. No clear indication of SCC was found. The application of tensile stress to 85 % of yield strength increased general corrosion rate significantly in very corrosive waters. The effect of corrosion protection on the axial behavior of steel strands was determined by double pipe axial tests with different embedment lengths. The results showed a significant difference on behavior between epoxy-coated steel strands, galvanized steel strands and plain steel strand. Dans la présente étude, nous avons passé en revue des méthodes permettant de classifier la corrosivité des eaux souterraines. Des tests portant sur les pertes de poids et sur la corrosion FCC (la fissuration par corrosion sous contrainte) ont été effectués pour les barres d’armature et les torons. Aucune indication nette de FCC n’a été constatée. L’application d’une contrainte de traction allant jusqu’à 85 % de la limite d’élasticité a accru de manière significative la vitesse générale de corrosion dans les eaux très corrosives. L’effet de la protection contre la corrosion sur le comportement axial des torons en acier a été déterminé au moyen de tests axiaux à double tube avec des longueurs d’enrobage différentes. Les résultats ont mis en évidence une différence significative quant au comportement entre les torons en acier à revêtement époxy, les torons en acier galvanisés et les torons en acier standard. In dieser Arbeit haben wir Methoden geprüft, die korrosive Wirkung des Grundwassers einstufen. Gewichtsverlust- und SCC-Korrosionstests wurden für Stahlstäbe und Drahtlitzen durchgeführt. Es wurden keine sicheren Hinweise auf Spannungsrisskorrosionsbrüche gefunden. Bei Anwendung einer Dehnbelastung von 85 % der Streckspannung bzw.Ergebnisstärke stieg die allgemeine Korrosionsrate in stark korrosivem Wasser deutlich an. Die Wirkung des Korrosionschutzes bei axialem Verhalten von Stahldrahtlitzen wurde durch axiale Tests an Doppelleitungen unterschiedlicher Versenkungslänge determiniert. Die Ergebnisse zeigten im direkten Vergleich von epoxidbeschichteten, galvanisierten und normalen Stahldrahtlitzen beachtliche Unterschiede im Verhalten auf.

Jan 1, 2003

By M. S. Moholwa, J. D. Steenkamp, H. L. Rutto

Manganese ores are the major source of manganese for the production of manganese ferroalloys. There is a gap in the knowledge of the decrepitation behaviour of manganese ores, which presents a problem in the operation of smelters. Decrepitation, which is the breakage of the ore particles upon heating, is an important quality parameter for these ores. The purpose of this investigation was to determine the extent to which South African manganese ores decrepitate during preheating in a rotary kiln. The effects of temperature, rotational speed, and particle size decrepitation were investigated. Manganese ores were heated in a laboratory-scale rotary kiln at temperatures of 600, 800, and 1000°C, and rotational speeds of 3, 6, and 12 r/min. The size ranges were +6-20, +20-40, and +40-75 mm and the residence time was constant at 30 minutes. The decrepitation index (DI) is quantified as the ratio of the mass of <6 mm particles after pre-heating to the total mass of the sample. It was found that the DIs for all ores used were proportional to the temperature and the rotational speed and inversely proportional to the particle size range with temperature being the most important parameter. Ore A was the most susceptible to decrepitation followed by ore C and ore B; this was mainly to the decomposition of kutnohorite, the content of which was the highest in ore A and the lowest in ore B.

Nov 30, 2022

By A. Y. Senchenkoa, Y. V. Kulikov

The relationships revealed between ore hardness and specific energy consumed by crushing and grinding are described in the paper. A comparison of key technical and economical parameters of SAG and HPGR circuits is made, based on testing of several ore types for greenfield projects. The comparison of results make it possible to estimate efficiency of the technologies application, depending on ore hardness and taking into account potential risks for a circuit under design. Keywords: Comminution circuits, SAG, HPGR, test results

Jan 1, 2020

By U. Atici, R. Comakli

"Understanding rock properties is of vital importance in mining and civil engineering. Rock properties are generally determined through laboratory tests, which require a large number of uniformly shaped samples and technicians who use indirect methods to determine rock properties. The texture coefficient (TC), which represents various textural parameters including the size, shape, orientation, and relative proportions of grains and the matrix, is an efficient means for indirectly evaluating the mechanical behaviour of rocks. In this study, 12 different rocks (ten granites, one diorite, and one gabbro) were collected and their engineering properties. including specific gravity, porosity, P- and S-wave velocities, Schmidt rebound hardness, uniaxial compressive strength, and elasticity modulus, were investigated. Relationships between TC and these measured properties were assessed. Statistically significant (at the 95% confidence level) correlations were found between the TC and compressive strength, elasticity modulus, sound velocity (both compression and shear waves for dry and saturated samples), but no significant correlation was found with Schmidt rebound hardness. The results suggest that it is possible to use the relationships between TC and the mechanical properties of rocks in rock classification. IntroductionIn every aspect of rock engineering, knowing rock properties is essential for determining and predicting the behaviour of rocks and rock masses. Mechanical properties of rocks are important parameters in mining, geology, and engineering, and they are affected by textural characteristics such as grain size, grain shape, cement type, degree of cementation, mineral content, and the ratio of the grain area to the matrix area. The effects of textural properties on the physical and mechanical properties of rocks have been investigated for a long time, and previous studies revealed close relationships between single parameters related to rock texture and mechanical properties of rocks (Akesson et al. 2001; Gunsallus and Kulhawy 1984; Merriam, Rieke, and Kim, 1970: Onodera and Kumara 1980; Prikryl 2006; Ulusay, Tureli, and Bider, 1994; Tugrul and Zarif 1998). Rock properties are usually determined using mechanical tests, which require uniformly shaped and relatively large samples. However, it is not always possible to obtain such samples. Furthermore, rocks with similar textural and structural properties may exhibit different mechanical behaviour. Howarth and Rowlands (1987) developed a texture coefficient (TC) that expresses all the main textural parameters of a rock in a single dimensionless quantity based primarily on statistical assessment. The TC makes it possible to understand the effects of a rock’s textural properties on its mechanical properties using thin sections instead of large, uniform samples. Ersoy and Waller (1995) investigated the relationship between strength and TC for limestone, sandstone, and siltstone; they also examined the effect of rock properties and TC on drilling performance. Ozturk, Nasuf, and Bilgin (2004) explored the relationship between rock quality and TC by evaluating the uniaxial compressive strength (UCS) values of limestone, basaltic andesite, and tuff. Gupta and Sharma (2012) evaluated TCs as well as the petrophysical and mechanical properties of quartzite from the lower and higher Himalayas and found a strong relationship between TC and UCS. Similarly, Ozcelik, Bayram, and Yasitli (2013) investigated the relationship between TC and various parameters in marble by applying the statistical analyses developed by Ozturk, Nasuf, and Kahraman (2014)."

Jan 1, 2019

By A. Rahmanab, A. Torpy, M. I. Pownceby, M. N. Zaman, N. Haque, W. Bruckard, J. Tardio

Ilmenite is the principal feedstock for producing TiO2 - used in paints, plastics and paper and the production of Ti metal. The Brahmaputra River system in Bangladesh represents a potentially new source of ilmenite concentrated within sandbar placer deposits and the current study presents results from beneficiation and characterisation studies conducted on Brahmaputra River Fe-Ti oxides. Characteristic of fluvial systems, the ilmenite concentration is low (~0.5 wt-%), however extensive annual dredging for waterway navigation provides the economic impetus to recover saleable ilmenite. The Fe-Ti oxide suite derived from magnetic fractionation comprises homogeneous ilmenite, titanohematite and hematite, although many grains exhibit complex exsolution within the (Ilm-Hem)ss series. The textural variability results in difficulty generating a pure ilmenite feedstock with the bulk concentrate typically being low in TiO2, containing 31.0 wt-%TiO2 and 62.7 wt-% (Fe2O3). Results are interpreted via an analysis of the implications for producing a commercial-grade ilmenite concentrate suitable for TiO2 production. Keywords: Ilmenite, titanohematite, Fe-Ti oxide exsolution, TiO2 production

Jan 1, 2020

By N. F. Dawson

Recovery of a chromite concentrate from UG2 flotation tailings streams, of a grade suitable for further pyrometallurgical treatment for the production of ferrochrome, has certain specific challenges not only by virtue of the decoupled nature of the primary PGM recovery process and secondary gravity based chromite recovery circuits, but also because of intrinsic variations in the nature of the ore and its mineral composition. Variability in the ore, together with upstream process dynamics, creates a challenging environment in which to achieve optimal recovery of a gravity concentrate with accurate grade control. This paper examines certain inter-relational aspects between the ore gangue and chromite mineral types, the influence of the primary PGM extraction circuit and secondary chromite extraction activity as applied specifically to UG2 ore against a background of actual plant experiences and circuit configurations applied in order achieve a suitable quality of chromite concentrate.

Jan 1, 2010

By K. Karaman

This study investigated the effect of surface roughness on Schmidt rebound hardness (RL). Four different test surfaces of rock samples were studied: natural, ground, cut surfaces, and core samples. There was significant variability of standard deviation based on the RL on the natural surface, which indicated high roughness of the rock surface, whereas surface polishing caused a significant decrease in standard deviation. ISRM and ASTM methods were compared to estimate unconfined compressive strength (UCS) for different testing surfaces. RL obtained from the cut surface was found to be more reliable than those obtained from other testing surfaces for the prediction of UCS; however, regression and ANOVA analyses revealed that the ISRM method gave a more accurate UCS estimation of rocks with highly rough surfaces. It was also shown that RL values obtained from a cut surface were significantly higher than those obtained from core samples. Therefore, a comparison between RL values obtained from core samples and cut surfaces was made based on previous studies. This study statistically showed that estimated UCS values are not statistically significant if Schmidt rebound tests are not performed on similar surfaces. In addition, the mineral grain sizes of the studied rocks, different testing surfaces compared with those in literature, and standard deviation from RL are evaluated and discussed. The Schmidt hammer technique is a rapid, inexpensive, and straightforward method for estimating UCS for preliminary assessment; however, roughness of the surface should be eliminated if variations are shown in the surface rebound hardness.

Apr 14, 2024

By W. Ferreira

Steel is produced in a basic oxygen furnace from hot metal obtained from a blast furnace. A sintered iron ore with good hightemperature properties (strength and permeability) should be used as feed to the blast furnace. The quality of this sintered ore depends on the reactivity of the iron ore used as feed to the sinter plant during the lime assimilation step in the sintering process. The penetration test is the standard method for evaluating the reactivity of iron ore with lime. It is, however, difficult to determine the exact depth of penetration from the standard test. A new test method is proposed that allows automatic evaluation of iron ores in terms of lime assimilation with increasing temperature. A comparison of the coefficients of variation for the new and standard methods for each ore type demonstrates that the results of the new test are more reproducible and more precise than those of the standard method. The test is also less time-consuming and easier to implement.

Jan 1, 2014

By A. Yañez, J. Yianatos, P. Vallejos, R. Grau

This paper presents an evaluation of the effect that the mineral feed characteristics have on the metallurgical performance in an industrial flotation circuit. Variables such as mineralogy, particle size, solid content and mineral grade were evaluated using a flotation simulator, which was previously developed and validated using industrial data from different concentrators. The metallurgical performance was evaluated not only from the point of view of recovery and concentrate grade, but also by analysing less common variables such as froth carrying rate, froth and collection recovery, water recovery and others. Then, new data from the industrial flotation circuit was used to complement this analysis and evaluate the simulator predictability by comparing simulated and measured data. The results allowed for the quantification of the significant effect that mineralogy and particle size have on recovery and/or concentrate grade. Therefore, the grinding stage and flotation cells design become important factors to avoid a significant loss in metallurgical performance when feed mineral characteristics change in an industrial operation. In this context, an evaluation of cells design and arrangement should be performed to compensate the loss in recovery and concentrate grade in order to find an optimal operating condition. Keywords: Flotation circuits, mineral feed, modelling, particle size, liberation, mineralogy

Jan 1, 2020

By K. L. Morton, R. .. J. Connelly, P. C. Bouw

Uncertainties in the forecasting of the volume of groundwater likely to enter underground workings present difficulties for mine management in planning and costing the water-related activities of mining. This paper describes a technique that was developed to assess future inflows into a gold mine in the Orange Free State. The approach employed was based on the interactive operation of two separate computer models: a regional-flow model and an inflow model. As a first stage, a regional finite-element model of groundwater flow was set up and calibrated. Predictive runs were made to establish the influence of mining on the water levels from base-line conditions. This step was necessary since observations of the regional water levels were sparse. The predicted water levels were transferred to the inflow model, and the future flowrates were calculated. Both models were calibrated by trial and error until a satisfactory match was obtained between historical records and the values predicted by modeling. In this way, an improved monitoring system to record regional water levels and pressure heads within a mine was established. By the use of information, the initial model predictions can be refined as mining progresses. The models used are based on a non-linear relationship between the area mined and the inflows. A phased behaviour in the rates of inflow increase was noted. In conclusion, the modeling approach can provide mine management with guidelines for dewatering requirements. The confidence levels depend upon the records that have been collected during the mine&apos;s history.

Jan 1, 1988

By D. Pienaar, C. O’Connor, B. McFadzean

Dithiophosphate (DTP) is classically used as a co-collector in sulphide mineral flotation, where xanthate-DTP mixtures have been shown to synergistically improve mineral flotation performance. Notwithstanding the improved recoveries observed, ethyl DTP does not appear to behave as a conventional collector, since it has been shown that it does not adsorb onto certain sulphide mineral surfaces. Recent investigations have nevertheless indicated that when ethyl DTP does not adsorb onto the sulphide mineral surface, the presence of a non-ionic frother can activate a synergistic increase in pulp phase mineral recovery, and bubble-particle attachment probability. A regular solution approach was used to determine the interactions between thiol collectors and non-ionic frothers at the air-water interface. Attractive interactions were observed between longer alkyl chain DTPs and frothers, whereas the activity of xanthates at the air-water interface were too weak to determine if an interaction was occurring. This is the first time that such interactions have been shown for the DTP-frother system and represents an important contribution to our understanding of the role of DTP reagents in the flotation process. Keywords: Collector-frother interaction, dithiophosphate, surfactant synergism

Jan 1, 2020

Exxaro installed their first ultra fines treatment plant at Leeuwpan Coal mine. The plant is now fully operational and results already show that the plant has great potential. The plant was designed and installed by DRA. Several challenges were faced during the installation due to the space constraints in the Leeuwpan plant. Efficiency tests were conducted on both modules after commissioning and showed very promising results. A lower ash product with a higher yield can be produced with the fine coal dense medium cyclones compared to the spirals previously employed.

Jan 1, 2010

By J. Bullón, A. Pérez

Some years ago, Ferroatlantica developed a new type of electrode known as the ELSA electrode. In this electrode there is a central graphite core that provides support, surrounded by an annulus of Søderberg paste that gets baked during operation. This technology has been implemented on several silicon furnaces around the world, and was reported on during the previous Infacon conference. In all electrodes, but particularly in the ELSA electrode, the quality and consistency of the paste are important for correct operation. As the type of paste varies between customers and between countries, Ferroatlantica has developed a quality control procedure for their customers of this technology. This procedure is geared to the point of view of the customer rather than the paste producer. The analysis is based on the desired flow pattern of the raw paste and on the desired mechanical and electrical properties of the baked paste, as experience has shown that these are the most important parameters to monitor in order to avoid having problems with the resulting electrodes. This paper discusses these methods of paste analysis in the light of complementary studies that have been done when there has been an electrode breakage in the different plants.

Jan 1, 2007

By K. H. Zhang, Y. P. Gao, J. Q. Zhao, Q. Li, J. C. Ma

Compared with sinusoidal oscillation, non-sinusoidal oscillation enhances the ability to control waveform and meets different oscillation requirements by adding an independent parameter, which is the key technology for high-efficiency continuous casting. A new waveform of mould non-sinusoidal oscillation is proposed in this paper, that is, a velocity waveform that is composed only of straight lines and parabolas, which not only has good dynamic characteristics, but also further enhances the feature of non-sinusoidal oscillation. Compared with sinusoidal oscillation, the negative strip time is reduced by 15.9%, the maximum negative strip velocity difference is increased by 38.3%, and the maximum positive strip velocity difference is decreased by 27.8%. The formulas of oscillation process parameters can be clearly deduced, and the isoplethic curves of oscillation process parameters when multi-parameter simultaneously changes are drawn. The negative strip time decreases as the modification ratio, frequency, and casting speed increase, but increases as stroke increases. In order to maintain the stability of negative strip time, an oscillation synchronous control model for optimising oscillation basic parameters was developed. Through practical application, the mean oscillation mark depths decreased by 10.1 μm and the flux consumption is increased from 0.37 kg/t to 0.45 kg/t in the non-sinusoidal oscillation model, which meets the requirements of normal production.

Oct 24, 2025

By J. E. Gebhardt, B. Temel Mckenna, W. Lee, C. S. Macomber

X-ray diffraction (XRD) data was extracted from various sources to develop qualitative ternary and tetrahedral plots differentiating mineralogy, bond work index (BWi) and hardness of ore bodies at different mine sites. A large number of historic reports and compiled characterization laboratory data were used to create a searchable "data lake." The data lake provides a means to locate, consolidate, and visually represent XRD from disparate sources. Visualizations with large amounts of mineral ore XRD characterization data provide a qualitative assessment of ore properties, including comminution qualities such as material hardness. The visual map can be employed to quickly estimate expected ore character and behavior, given XRD analysis of samples from newly characterized and unfamiliar ore. Keywords: Mineralogy, Characterization, Comminution, Database, Ternary, Tetrahedral

Jan 1, 2020

By J. E. Xu, J. Y. Zhang, M. Q. Sheng, K. Wan

"SynopsisThe densities of selected CaO-Al2O3-MgO slag systems were measured at 1823K by the Archimedean method. Thirteen different slag compositions were chosen based on different levels of the MgO content and the mass ratio of CaO/Al2O3. The results indicated that the density of the slag decreases with increasing MgO content (from 0–3.78 mass%), but increases with further increases in MgO content up to 11.33 mass%. At a fixed MgO content of 5.5%, the trend of density change with CaO/Al2O3 in the slag is similar to that for changes in MgO content. On the basis of the regular solution approximation rules of excess molar quantities, an attempt was made to estimate the molar volume of the slags investigated. The application of the molar volume model confirmed that the present expanded approximation rules are applicable to predict the molar volumes of the melts discussed.IntroductionDensity is one of the most important fundamental properties of slags, which influences metallurgicaly phenomena in many ways. Density is sensitive to the nature of the chemical bonds and the species in the melt, and is of great importance not only for theoretical research on the structural properties of molten slags, but also for industrial applications. Density is also required to estimate other key properties used to assess the behaviour of high-temperature molten oxides, e.g. viscosity, surface tension, and thermal conductivity.Liquid calcium aluminate slags that contain magnesia are the basis of most ladle slags for secondary refining processes. The CaO-Al2O3 binary phase diagram (Hallstedt , 1990) shows the eutectic composition (50 wt% CaO and wt% Al2O3) has the lowest melting temperature. The main emphasis of this study is on the 12CaO·7Al2O3 refining slag with MgO additions. The CaO-Al2O3-MgO ternary system is of considerable importance in industrial metallurgical processes, and is fundamental to the understanding of metallurgical slags, ceramic materials, and geological phenomena."

Jan 1, 2015

By A. Tosun

"The size distribution of the muckpile formed as a result of open pit blasting operations has a considerable effect on the efficiency of loading, hauling, and crushing. Various researchers have developed specialized computer software that uses image analysis methods for determining the size distribution of the muckpile. However, these methods have some limitations. One of the most important of these limitations is that the very fine fragments in the muckpile cannot be used in the size distribution calculation. In this study, 18 test blasts in total were carried out in two limestone quarries belonging to Batiçim Corp. in Izmir, Turkey. A new model was developed in order to ensure that very fine fragments are used in the size distribution calculation. The size distributions of the test blasts were calculated by both the Wipfrag computer program and the new model. Correlations were established between the muckpile size distributions determined by both methods and the parameters determining the efficiency of the loader. IntroductionThe size distribution of the muckpile formed as a result of open pit blasting operations has a considerable effect on the efficiency of loading, hauling, and crushing. Various researchers have established certain correlations for predicting the efficiency of the operations according to the muckpile size distribution so that production can be carried out economically (Tunstall and Bearman, 1997; Nielsen and Kristiansen, 1996; Workman and Eloranta, 2004; Michaud and Blanchet, 1996; Frimpong, Kabongo, and Davies, 1996; Osanloo and Hekmat, 2005; Molotilov et al., 2010). In these studies, the 50% passing size (X50) is generally used. These methods rely on the correct measurement of the size distribution of the muckpile formed by the blast. The most reliable measurement method would be to subject the entire muckpile to a sieve analysis, but this is obviously impracticable. Therefore, computational method based on image analysis have been developed. These include IPACS (Dahlhielm, 1996), Tucips (Havermann and Vogt, 1996), Fragscan (Schleifer and Tessier, 1996), Cias (Downs and Kettunen, 1996), GoldSize (Kleine annd Cameron, 1996), Wipfrag (Maerz, Palangio, and Franklin, 1996), Split Desktop (Kemeny, 1994), PowerSieve (Chung and Noy, 1996), and Fragalyst (Raina et al., 2002). In these methods, the size limits of the fragments forming the material are determined by image analysis on photographs of the muckpile. However, the computer software has some limitations. It does not take into account the third dimension of the muckpile, nor the size distribution of very fine fragments. In particular, the fragment size ranges below 2.5 to 3 cm cannot be determined, and therefore these cannot be included in the muckpile size distribution. However, the muckpile formed by a bench blast contains a wide range of particle sizes (Tosun et al., 2015)."

Oct 1, 2018