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By Dwight L. Sawyer, Roy T. Sorensen

The Bureau of Mines has investigated the recovery of alumina by hydrochloric acid leaching of calcined kaolinitic clay . Bench- scale studies indicated that horizontal belt filtration was a pprraaccttiiccaall method for separating the siliceous residue from aluminum chloride liquor generated in the leaching step . Miniplant -scale continuous testing was performed to evaluate the filter circuits and to compare filtration response of different calcined kaolin feed materials and of different agitatorbaffle designs in the leaching reactors . Soluble alumina recovery with a single filter ranged from 94 pct with minus 10 -mesh feed more than 96 pct with minus 35-mesh or misted feed . Process advantages were confirmed for the calcined misted kaolin feed material prepared by a Bureau-developed misting process . With two filters in series , an overall filtration rate of 100 lb solids /hr.ft - 2 of filter area was attained with a soluble alumina recovery of more than 99 pct . More than 99.5 pct alumina recovery was obtained with a thickener and a two - filter circuit for either the minus 35-mesh or the misted feed . Modifications in leaching reactor design made to decrease particle- toparticle attrition were successful and significantly increased filtration rates and decreased flocculant requirements .

Jan 1, 1965

By F. Warnaars

Historically, this area produced gold and silver from many well-known vein deposits, like Tayoltita, Topia, and San Jose de Gracia. Modern exploration identified three categories of deposits: 1) low grade porphyry golds in shallow level dacite porphyries; 2) batholith-related deposits; and 3) those formed in volcanic sequences of Late Cretaceous to Late Tertiary. At least four porphyry golds have been identified, of which Metates is best known. These are formed by and within dacite porphyries, associated hydrothermal breccias and sometimes within surrounding metasediments. Their ages are from mid-Cretaceous to Early Tertiary. Precious metal deposits associated with batholiths occur as veins, contact haloes in metasediments or volcanics, skarns, tectonic breccias, hydrothermal tourmaline breccias, dacite dikes or as disseminated or stockwork deposits such as La Fortuna. Several new gold discoveries were made in older Early Tertiary Volcanic Sequences and in the younger Tertiary volcanics within prominent structures exceeding 3 to 5 km in lengths. Some of these are open-pittable but most have to be mined by underground methods.

Jan 1, 1999

During 2009 the technical services staff at Barrick Gold Corporation's Australian Business Unit conducted a review of their five underground mines that utilise pastefill as the backfill component for these operations. Of the five mines reviewed three use dry tailings and two use wet tailings plants. The primary aim for these reviews was to determine whether pastefill was the right option to be used, and if not, what where the alternatives. The reviews undertaken focus on several areas including, paste plant operation, reticulation and barricade techniques, the geotechnical requirements for pastefill in regards to the current mining methods, the consideration of alternative methods, capital and operating cost histories compared to initial estimates, and a cost benefit analysis of pastefill against other mining methods. The main benefits from the use of pastefill is increasing the extraction of the resource, reducing or eliminating the need to leave pillars. In some mines the use of pastefill is geotechnically driven, to manage high stress environments or mining induced seismicity. A third benefit of using pastefill in some circumstances is that it reduces dilution, however it is considered that this is not a valid argument for most of the mines reviewed. At two mines no alternative to pastefill was determined, whilst differing extraction and filling strategies were potentially identified at the other three mines. The reviews developed cost benefit curves for those sites that had alternative mining methods to assist in determining whether pastefill is the right option to use for any particular stope. At the grades typically mined in each operation, pastefill was the preferred option to use. In all mines, pastefill was determined to be the best option at this time.

Nov 25, 2010

By R. E. Mussier

This investigation was made to study new methods to prepare high-purity yttrium metal, Various methods were used to prepare pure intermediate compounds, primarily chlorides, bromides, and iodides, which were subsequently reduced to metal. The process found most suitable for the preparation of pure anhydrous yttrium chloride involved thermal dehydration of a mixture of hydrated yttrium chloride and ammonium chloride while under vacuum. Yttrium bromide and iodide were prepared most effectively by the direct halogenation of yttrim carbide. Yttrim carbide was obtained by reacting and melting yttrium oxide-carbon mixtures in a carbon-arc furnace. Yttrium halides were purified by vacuum distillation and reduced by alkali or alkaline-earth metals. Lithium and sodium proved to be the best reductants from the standpoint of yield (>95 pct) and purity (>99.8 pct) of the yttrium. The product of the reduction step was sponge metal, which was consolidated readily by conventional cold-mold, arc-melting procedure. The purest yttrium obtained in laboratory scale work was prepared by sodium reduction of yttrium chloride and contained only 125 pp oxygen; other impurities did not exceed 1,000 ppm. In larger scale tests yttrium containing only 800 to 1,000 ppm total impurities was obtained by lithium reduction of yttrium chloride. The tensile properties of high-purity yttrium were determined. Mechanical tests showed that yttrium can be forged, extruded, rolled, spot welded, and deep drawn.

Jan 1, 1963

Near-Infrared Spectroscopy (NIRS) Sorting in the Upgrading and Processing of Skorpion Non-Sulfide Zinc Ore In 2008 Anglo American sponsored a research project at RWTH Aachen University to assess the feasibility of the use of near-infrared spectroscopy (NIRS) for ore waste discrimination at the Skorpion zinc mine. The Skorpion mine is an open pit zinc mine located in Namibia, owned by Anglo American with an annual production of 150 000 t/a of super high grade pure zinc. Opportunities for the implementation of NIRS sorting for the Skorpion process exist to upgrade currently subeconomic material, including the marginal dump (over 2000 000 tonnes, av grade of 2.5 per cent Zn). NIRS sorting is not yet implemented or established in the minerals industry however it is a proven technology in the plastics recycling industry, where more than 2000 NIRS sorters have already been installed. NIRS sorting, a type of sensor-based sorting, is a single particle sorting technique which classifies the particles based on the absorbed/reflected radiation in the near-infrared (NIR) region. A disadvantage of NIRS is that it is a surface measurement technique, but NIRS sorting shows overall great potential for the minerals industry. Skorpion ore minerals include zinc bearing phases such as sauconite, hemimorphite, smithsonite, and hydrozincite. These display diagnostic responses in the near-infrared. There are three major absorption features that characterise the reflectance spectra of the ore bearing minerals. These are due to OH and H2O molecular bonds. The spectral response of the waste material is caused by other minerals such as non-zinc-bearing clay minerals, calcite and impure quartz. Test work showed that it is theoretically possible to separate ore material from most waste material based on spectral response in the NIR region. In addition to upgrading material by removal of waste it is also potentially feasible to classify the material based on zinc grade. A tentative correlation between zinc grade and spectral response seems to exist for the sample test suite in the NIR region.

Sep 13, 2010

By S. J. Buckler

Many metallurgical processes use submerged gas injection to increase the contact area between gas and liquid phases in order to promote faster overall reaction rates. The work presented in this paper is part of an experimental investigation to measure the gas-liquid interfacial area available in bubble plumes within molten metal baths. Measurements of the nitrogen absorption rate during submerged injection into molten iron baths have been used to estimate the interfacial areas of the bubble plumes. A theoretical model was used to predict the superficial nitrogen transfer rate under mixed liquid phase mass transfer -interfacial reaction control. The interfacial area was calculated by dividing the overall nitrogen absorption rate by the superficial rate. Reasonable agreement was obtained between the interfacial areas measured in our laboratory with data from a comparable system reported in the literature. The experimental results were compared with the predictions of three theoretical models and one empirical correlation. The models of Turkdogan (3) and Zhao and Themelis (5) gave the best agreement with our data.

Jan 1, 2004

By L D. Munro, S A. Jackson

This paper provides a logical approach to developing a TSF design concept through: • Identifying key properties of tailings and containment structures; • Reviewing underlying principles for effective operation; • Showing how these apply to select an appropriate TMS; and • Demonstrating how to align the TMS to site-specific constraints and TSF design. This approach follows a path of rigorous data analysis independent of discharge parameters (whether low-density slurry, paste or cake disposal) to select the most cost-effective and sustainable approach for any given material or site.

Jul 1, 2021

By Reinhold A. Errath

The Antamina Concentrator plant was one of the first plants in the world, where about 60 Megawatt only in Milling Power was installed. As a consecuence of the use of Gearless Mill Drives the speed of the mills is adjustable, which allows the operators react to the different ore grades correspondingly, in order to get the best results in terms of milling efficiency. In this sense, this paper describe the basic idea of a Gearless Mill Drive, the construction of it, the manufacturing facilities, the transport, the installation and the function in detail. It gave enough insights to understand why Gearless Mill Drives are so reliable and used as an adjustable speed drive, why it counts with the highest efficiency of all drive systems.But it did describe as well the overload capabilities, the reaction to the network, the reason why the maintenance of the drive system is proven as a minor issue, and finally it was self- explaining why the Gearless Mill Drive is called a working horse.

Sep 12, 2005

By J. J. Crowder, A. L. Coulson

Ground support is a significant component of underground mining costs. The rehabilitation of failed support, however, is often much more expensive than the initial installation. This paper investigates whether the right type and length of support can be designed correctly the first time, through forward modelling of the support and the mining process. Back analyses demonstrate how high-quality instrumentation and monitoring can help with the estimation of the post-peak (post-failure) rock mass parameters required for a comprehensive analysis. A hybrid modelling approach combines a three-dimensional mine-wide boundary element model with a non-linear finite element model to allow for the failure process in the rock mass. The back analyses demonstrate that, for the case study site, the post-peak Generalized Hoek-Brown value of mr must be reduced significantly in order to properly simulate displacements observed in instrumentation data. High-quality instrumentation data is the key to post-peak rock mass parameter calibration. The procedures outlined in the paper highlight the need for a new hybrid numerical modelling package that can use the influence of three-dimensional mining-induced stresses to predict displacements in, and potential failure of, rock masses surrounding mining infrastructure in order to radically alter strategic and tactical mine design.

Jan 1, 2007

By C Catania

Mining companies and operations across the globe typically target best practice financial management, along with a focus on economically driven mine plans. Not only is this inherent in running a successful mining business, but also critical in addressing investor scrutiny. The standards for social and environmental practices is less consistent than this, with most companies adopting standards that are driven through legislative and compliance requirements of the nations in which they operate. Although there is still room for improvement, Australian is a country that stands at the forefront of social and environmental legislation, driving more sustainable planning practices for mining operations, with an ever-increasing focus on mine closure considerations. Of the many nations yet to reach such a legislative position, Kazakhstan is a place where some companies are driving towards world class standards beyond what is government mandated. CITATION:Catania, C, 2018. World-class mine planning for a sustainable future in Kazakhstan Mining, in Proceedings Life-of-Mine 2018, pp 6–7 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Haghi. Hamed, Javad Vazifeh Mehrabani, Mehdi Sedigh

In this investigation, the possibility of physical separation methods such as attrition scrubbing, hydro-cycloning and also reverse flotation were investigated for silica and calcite removal from relatively low grade kaolin. The head sample was provided by the Iran China Clay Company and the major oxides contained in the head sample were Al2O3, SiO2, CaO and Fe2O3 with grades of 15.07%, 71.05%, 4.35% and 0.52% respectively. The liberation degree of calcite and iron impurities from kaolin particles were over 80% for particles finer than 210µm and 53µm respectively. Attrition scrubbing tests were carried out with scrubber cell of the conventional Denver flotation cell model D-12. Laboratory scale hydro cyclone was applied for the beneficiation of kaolin. Attrition scrubbing tests with control screen of 106µm did not achieve the desirable yield for purification of this kaolin sample, but hydro cyclone experiments resulted in better results. Hydro cyclone with 2.54 cm diameter used and the only variable was the cyclone inlet pressure ranging from 68.65kPa to 98.07kPa. The best inlet pressure was found to be 68.65kPa. Based on the optimized condition, Al2O3 and CaO amount in the hydro-cyclone overflow was 23% and 1.47% respectively. However weight recovery of the overflow in each cyclone experiment was less than 30% and multi stages of hydro-cyclones would have to be applied for higher weight recovery and better yield. All of the flotation tests were carried out in the conventional Denver flotation cell model D-12. Reverse floatation tests for calcite removal were carried out under alkali pH based on full factorial design of variables in 2 levels including one center point. The three parameters tested were collector dosage (gr/ton), pH and depressant dosage (gr/ton). The collected data from flotation tests were analyzed and optimized collector and depressant dosage were 1000 gr/ton and optimized pH was 8.5. Under the above mentioned conditions, calcite removal was about 75% and CaO content in the final product was reduced from 4.35% to 1.33%. However calcite removal will increase to more than 83% if the feed particle size in flotation tests is reduced from 210µm to finer than 53µm. Finally after optimization, the best working condition and possible flow sheet were developed.

Jan 1, 2014

By E. H. Christiansen

The most valuable gem- quality red beryl comes from the Wah Wah Mountains of south-western Utah (Fig. 1). Red beryl occurs as a secondary mineral in topaz rhyolite. Marketable crystals from the Wah Wah Mountains have been produced from the Violet Mine, operated on a limited scale since 1976 under the ownership of the Harris family of Delta, UT. From 1989 to 1995, production from the mine amounted to more than $3 million with an inventory of several million dollars of unsold gems (Harris, 1995). In 1994, Kennecott Exploration leased the mine and surrounding claims to determine reserves and feasibility of gem recovery. Mining and exploration activity are continuing. Previous work on red beryl has dealt mainly with crystallographic, chemical and optical properties of the crystals (Shigley and Foord, 1984) with only general descriptions of the geology (Ream, 1979). However, the conditions needed for formation of red beryl have not been well constrained. It is generally proposed that beryl originates by precipitation in fractures and vugs from high-temperature gases as they are released from slowly cooled rhyolite lava. Dozens of topaz rhyolite flows and domes, similar in composition to the beryl-bearing flow in the Wah Wah Mountains, occur across the western United States (Christiansen et al., 1986). All of these flows devitrified to form vapor-phase topaz and locally other vapor-phase minerals such as bixbyite, garnet, hematite, pseudo-broo- kite and fluorite. But the occurrence of beryl is rare. Even within the rhyolite flow that hosts the red beryl, the productive open pits comprise only a small fraction of the surface area of the flow. Apparently, the conditions that favor the formation of red beryl are rarely achieved. Geologic setting The rhyolite flow that hosts the red beryl deposit lies along the eastern flank of the Wah Wah Mountains (Fig. 1). Prevolcanic rocks consist of Proterozoic, Paleozoic and Mesozoic sedimentary rocks that were folded and thrust to the east during the Sevier orogeny. Cenozoic volcanism began about 34 Ma. It consisted mostly of large volume dacitic ash flows and lesser volumes of low- silica rhyolite and andesitic lava flows. Beginning about 23 Ma, the style and composition of volcanism changed to smaller-volume, ash-flow and dome-forming eruptions of high-silica rhyolite and trachyandesitic lava. These rocks form the Blawn Formation of which the beryl-bearing rhyolite is one member (Best et al., 1987). Abbott et al. (1983) reported a K-Ar age of 22.1 + 0.8 Ma for this flow. It is probably the oldest topaz rhyolite flow in the Wah Wah Mountains. A subsequent episode (12 to 13 Ma) of bimodal magmatism produced the Steamboat Mountain Formation. The rhyolitic part of that is locally topaz-bearing. Displacement on the late Cenozoic extensional faults that formed the north-trending mountain ranges began about 22 Ma. Geology of the Violet Mine The rhyolite that hosts the red beryl deposit is part of a flowldome complex that overlies nonwelded tuff of cogenetic origin. This rhyolite is exposed over an area of about 9 km2 (3.5 sq miles) (Fig. 1). An unknown additional portion of the rhyolite is concealed beneath younger mafic lavas and sediments.

Jan 1, 1997

By M Recabarren, A Echeverria, J Ronda, J I. Guzman, R Dodds, G Juarez, E Vila-Echague

A strategic mine plan is a fundamental part of any mining operation. It must provide a realistic and operative extraction and processing schedule, and yield the highest value for the business. For open pit mines, the problem can be modelled as a set of blocks representing the deposit, for each of which we need to decide if it is going to be mined, if so, when and where it will be sent (process, stock or dump).This problem can be proven to be of NP-Hard complexity. The traditional approach used by mining engineers to tackle this complexity is to separate the problem into more tractable components, solving each separately. The first step is to use the Lerchs-Grossman (LG) algorithm to obtain the final pit limit, as well as a set of optimised pit shells (nested pits), using different input prices. Then, using this input, operational phases are designed. Third, the set of phases can be used as an input for a phase-bench style optimisation, usually using a mathematical programming-based algorithm.There are, however, several problems with this approach. First, dividing the problem into simpler parts has the consequence that any compromises made at early stages limit the potential value left for the following steps. Second, LG is a static algorithm, with no concept of the time-value of money, capacity limits, opportunity costs, etc. Phase design is essentially a manual step, for which nested pits provide insufficient information in practice, and therefore the quality of the result in terms of potential net present value (NPV) depends strongly on the experience and expertise of the designer. This means that key input data such as commodity prices, different processes capacities and mine movement limits, are considered only at scheduling, when there is little room for optimisation. This sequential approach limits the potential value in each step, where a simplified problem is addressed, instead of addressing the real, and more complex problem, which is dynamic and should be solved as a whole.We present in this paper an algorithm, and its commercial software implementation, that addresses the dynamic problem as a whole, simultaneously and automatically creating a high-value strategic mine plan that adheres to basic operational constraints, determining dynamic cut-off grades and delivering a set of phases which can serve as a much stronger guide than nested pits for the final design. We discuss some of the key elements of the algorithm and propose a new methodology for strategic mine planning, where phase design dynamically responds to mining strategy definition. Results using different mining and operational parameters on a fictitious copper deposit are used as a demonstrative example.CITATION:Juarez, G, Dodds, R, Echeverria, A, Guzman, J I, Recabarren, M, Ronda, J and Vila-Echague, E, 2014. Open pit strategic mine planning with automatic phase generation, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 147–154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By A. P. Schissler

2013 has seen metals, industrial minerals, and coal all reduce in price due to market and geo-political factors. Many companies are taking write-downs to recalibrate their reserves and have enacted focused cost reduction programs. The public domain includes statements where companies have operating cost reduction goals in the $500 million range. Zero-base staffing & budget analysis is a means to achieve optimal employment and cost levels for a given level of production. The method involves measuring the work to be done similar to Lean. Lean is a method to review each step of production and remove anything that doesn?t add value or is necessary to complete finished goods. Zero-base methodology has been applied to mines worldwide producing realistic and sustainable levels of staffing and costs based on the quantity of work. The objective of this paper is to provide the framework of zero-basing with examples of application.

Feb 23, 2014

By M. Kaya

This paper presents an experimental method to determine the degree of gangue entrainment in mechanical flotation cells and proposes new and inexpensive methods to lessen it. The applicability of froth washing and vibration was studied in laboratory, pilot plant, and plant scales. The effect of wash water on metallurgical performance was tested with various streams from the Falconbridge Strathcona mill at laboratory, pilot, and plant scales, with the 2nd cleaner at the Eastmaque Kirkland Lake mill, and with the 2nd and 3rd zinc and 3rd and 4th copper cleaners at Les Mines Selbaie mill. It was found that gangue recovery was closely related to water recovery in all systems. Wash water at an optimum superficial rate from 0.03 to 0.07 cm/s reduced entrainment by anywhere from 30X to 70X. Wash water can be further assisted by mechanical and ultrasonic vibration of the froth. A further rejection of 10 to 20X becomes possible. As a result of this work, a number of plants in Canada and in the United States have evaluated and/or are now using froth washing.

Jan 1, 1990

By W. A. Wall, R. L. Kidd

IN present-day flotation practice, grinding of the flotation feed is carried to extremely fine sizes, 70 to 80 per cent minus 200 mesh being customary. The greatest flotation losses occur in the coarsest and finest sizes, but the losses in the very fine sizes are, of course, much the more important because of the large proportion of fines in the feed. These losses are particularly high in zinc ores so a study of the effect of size on the flotation of sphalerite has been made. The mineral used in these experi¬ments was a pure sphalerite, especially free from copper, from the Joplin district in Missouri. The sizes coarser than 200 mesh were separated by screening, the sized mineral then being deslimed on a Wilfley table. The sizes finer than 200 mesh were obtained by water elutriation as described by H. R. Bradford (M. S. Thesis, University of Utah, 1932) ; particles finer than 6.5 microns could not be obtained with the apparatus used.

Jan 1, 1933

By Sergio N. Monteiro

Jute fiber reinforced polymer composites are among the most investigated and applied natural composites. In this past decade the mechanical properties of these composites has been assessed for various types of test conditions. However, the reported results correspond mainly to short-cut jute fiber composites, which do not present the highest mechanical strength as compared to continuous fibers of the same kind. In order to complement these results, the present work evaluated the mechanical behavior, by means of flexural tests, of polyester matrix composites reinforced with continuous jute fibers. Bend tests were conducted in standard specimens with up to 40% of jute. Fracture analysis by SEM displayed the rupture mechanisms. The results showed an improvement in some flexural properties with incorporation of jute fiber. However, a low fiber/matrix interfacial stress was responsible for limitation in the values attained by some properties.

Jan 1, 2010

Use of Impact Crushing for the Enrichment of Low-Grade Colemanite Concentrates This paper presents the results of an investigation into the enrichment of -25+3 mm low grade colemanite concentrates exploiting differential breakage properties of various minerals associated within the ore sample. Boric acid production process requires concentrates containing at least 42 per cent B2O3, hence concentrates below this grade either stock piled or further treated to increase B2O3 content. The low grade concentrate is obtained as a by-product of Emet Colemanite Concentrator and the B2O3 content may vary around 37 - 38 per cent. The sample used in the experimental studies assays 37.52 per cent B2O3. In the experimental procedures the sample was crushed using a laboratory size horizontal shaft impact crusher and the products were classified into different size fractions by screening so that any improvement by size could be observed. In the tests the effects of parameters such as the revolution speed of the crusher and heat treatment was checked. Test results prove that boron contents show a tendency to increase as the particle size decreases. As a result of the experimental studies a colemanite concentrate assaying 42.13 per cent B2O3 is produced with 76.55  per cent recovery. Arsenic content is seen to change inversely proportional with the B2O3 content of the concentrate such that it drops from 1016 ppm from the as received sample to 676 ppm in the concentrate.

Sep 13, 2010

By F. H. Samuel, J. E. Gruzleski, S. Valtierra, H. W. Doty, F. J. Tavitas-Medrano

319-type cast Al-Si-Cu-Mg alloys are commercially important due to their popular use in automotive applications. Artificial aging heat treatments are commonly performed in these alloys to achieve precipitation hardening and, therefore, improve their mechanical properties. The present work was carried out to investigate the effect of conventional (at a constant temperature, as specified by the standard T6 heat treatment regime), and non-conventional multi-temperature and interrupted aging cycles on the hardness, tensile and impact properties of two 319-type alloys (with and without Sr+ Mg additions). The results show that certain multi-temperature aging cycles have a more favourable effect in improving some mechanical properties than conventional cycles.

Jan 1, 2006

By T Seifert, P Krolop, K Niiranen, S Gilbricht

The Per Geijer iron oxide apatite deposits (IOA) display significant potential mineral resources for Luossavaara-Kiirunavaara AB (publ), known as LKAB. LKAB continuously mines magnetite/hematite ores in northern Sweden for almost 130 years. The Per Geijer deposits reveal a high phosphorus content and vary from magnetite-dominated to hematite-dominated ores, respectively. Furthermore, they show a large variation in texture, mineral composition, and relation to wall rocks. The high phosphorus concentration of these ores results from highly elevated content of apatite as gangue mineral. Reliable, robust, and qualitative characterisation of the mineralisation is required as these ores inherit complex mineralogical and textural features. For this purpose, comminution tests at laboratory scale in combination with scanning electron microscopy-mineral liberation analysis (SEMMLA) were carried out. Based on this work, significant information on the modal mineralogy and degree of liberation of minerals of economic interest (eg magnetite, hematite, and apatite) were obtained. Results show that there is a difference in the degree of liberation of magnetite and hematite between ore types. This seems to be dependent both on the size fractions and the dominance of each iron oxide in the individual ore type. The amount of gangue minerals seems to have no significant impact on the degree of liberation after comminution. Apatite is generally best liberated in ore types associated with silicates, regardless of magnetite or hematite dominance. Based on the results of this study it can be inferred that a high degree of liberation of the minerals of economic interest can be achieved. However, results need to be verified with further beneficiation steps such magnetic separation, apatite flotation and possibly reverse silicate flotation.

Nov 8, 2021