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By John Ralston, Stephen Grano, Yongjun Peng, Daniel Fornasiero

"A specially designed mill which allowed the control of pH throughout grinding was used to study the effect of grinding conditions on galena flotation and galena separation from pyrite. The changes occurring on the mineral surface during grinding were investigated by EDTA extraction and ToF-SIMS measurements.Galena flotation and galena separation from pyrite were strongly dependent on the type and amount of oxidation species produced on galena and pyrite surfaces under different grinding conditions. Iron oxidation species depressed both galena and pyrite flotation, whilst lead oxidation species activated pyrite flotation but had little effect on galena flotation. Optimum galena flotation and galena selectivity against pyrite were achieved by selecting grinding conditions that enabled lead and iron oxidation production to be controlled.Grinding conditions had a large effect on the flotation of the galena particles of different sizes. Flotation of fine galena particles (-10 µm) was depressed by iron oxidation species derived from the grinding media. Chromium grinding medium decreased the production of iron oxidation species and therefore increased the flotation of fine galena particles."

Jan 1, 2003

By Norman Paley

A blasting project was undertaken at the Teck Alaska Red Dog Mine in 2005 to 2007 to determine the extent that using electronic detonators could increase Semi-Autogenous Grinding (SAG) mill throughput. The results of that project were reported at the 2010 ISEE Annual Conference. This paper is a postscript to that project and provides the fragmentation resulting from the implementation of a 15% pattern expansion using electronic detonators.

Jan 1, 2012

By O. M. Arafat, J. A. Finch

Since its development, the functional performance equation for ball milling (McIvor, 1988) has facilitated a new understanding of industrial circuit cause and effect relationships, leading to significant strides in operational performance. Success stories of this approach to plant circuit performance improvement are now too numerous to list. Finch and McIvor (circa 1986) also discovered that the functional performance mill grinding rate at the size of interest was the same cumulative grinding rate that is calculated from mill feed and discharge size distributions using a first-order rate equation. By calculating these cumulative grinding rates for all screen sizes, a complete ball mill model is generated (as used by Finch and Ramirez, 1981). Others in industry, Hinde and Kalala (2009), for example, have noted the same. Lacking the complexity needed to maintain their interest, most researchers have ignored this model, broadly opting instead for Epstein’s (1948) characterization of grinding as a chemical reaction, combining selection rate and breakage size distribution functions. The much simpler ball mill model has previously been incorporated into a proprietary circuit modeling program (McIvor, 2005) and used for plant improvement work (for example, see McIvor and Finch, 2007, and McIvor, 2014). Now, by combining this business-friendly ball mill model with optimization criteria from functional performance analysis, a circuit modeling system (including the needed supplementary steps to assure successful plant implementation of circuit design changes) is at the disposal of every plant metallurgist, grinding equipment/ material provider and circuit designer.

Jan 11, 2017

By Elmer Palmer

As part of the Goldcorp Inc growth plan Minera Peñasquito SA de CV has developed its polymetallic deposit with a large ?state of the art? concentrator to process lead and zinc ores. The plant consists of two grinding lines including 38ft diameter SAG mills and 24ft diameter ball mills. During mid to late 2009 concentrator commissioning activities commenced. First concentrates were produced in October 2009 and now the plant is meeting its design basis of 65,000 mtpd per line. This paper describes the design and operational experience to date for its grinding circuit design, together with the recently commissioned HPGR crushing circuit.

Jan 1, 2012

By M. Pawlik, E. Arinaitwe, V. Ferrera

A series of flocculation tests were performed on dilute quartz suspensions with the use of five polyacrylamide-based flocculants of similar molecular weights but of different degrees of anionicity. The tests were performed as a function of ionic strength and pH. The macromolecular conformation of flocculants in solution was assessed through intrinsic viscosity measurements under the same physicochemical conditions as those of the flocculation tests. It was generally found that the flocculating efficiency of the polyacrylamides correlated with their ability to coil or stretch in solution. Polyacrylamides with the degrees of anionicity on the order of 10-18% showed the highest flocculating efficiency in terms of the settling rates of the flocculated solids and the residual turbidity of the resulting supernatant. At the same time, these most effective flocculants were also found to exhibit the greatest tendency to coil and stretch in solution. This result suggests that the flocculating power of a flocculant is determined not only by its ability to adsorb onto (and bridge) fine particles but also on its ability to conform to the size of the resulting floes.

Jan 1, 2009

By B. Markovic

Performance of mineral filler particles in ceramic applications can be enhanced markedly by adsorbing polymers of optimum molecular structure and dosage. In a recent work by Chen and Somasundaran (1997), a novel scheme of controlled polymer adsorption was used to produce nanocomposites of unique core-shell designs. Towards this purpose, adsorption and desorption behavior of selected polyacrylic acids (PAA) on three minerals; alumina, titania, and silicon carbide, was examined as a function of relevant parameters. Adsorption of P AA was found to depend on polymer molecular weight, pH, as well as solids loading. Specifically, the adsorption density was found to increase with increase in polymer molecular weight for non-porous alumina while it was found to decrease in the case of porous alumina. This is attributed to the inaccessibility of the pores to the larger polymers. An unexpected finding was the change in the adsorption density of PAA with solids loadings. PAA adsorbs on silicon carbide only at low pH values when the particles have very low surface charge suggesting that the adsorption in this case is controlled by electrostatic forces. Using polyacrylic acid as bridging agent between the alumina fillers (core) and nanosize alumina or titania particles (shells), controlled layer by layer deposition of nanoparticle on the core particle surface could be obtained.

Jan 1, 1997

By W. A. Lang

"IntroductionCARBONIZATION, gasification, and chemical utilization of coal are interrelated topics, which makes it difficult to review one without indicating its connection with the others. Hence, in Progress in Coal Technology, Series No. 5: Carbonization, reference was made to gaseous products recovered in the carbonization of coal, and .to a number of chemicals made from the tars, light oils, and ammoniacal liquors which are by-products of coal carbonization.In this, the sixth paper in the review series, prime consideration will be given to the complete gasification of coal to give a fuel for domestic industrial, or power purposes and a synthesis gas suitable for the manufacture of gasoline, Diesel oil, and chemicals. The hydrogenation of coal, an alternative source of liquid fuels and of chemicals, will be reviewed, as will be a number of processes for •the recovery of chemical products from coal by extraction and chemical treatment."

Jan 1, 1952

By Yiling Zhang, Paul A. Salvador, Gregory S. Rohrer

"Photocatalysis utilizes solar energy to produce hydrogen by splitting H2O. When a thin film of photocatalyst TiO2 is supported on a ferroelectric BiFeO3 substrate (band gap ~2.5 eV), the TiO2/BiFeO3 heterostructure is capable of photochemically reducing Ag+ to Ag0 in aqueous solutions under blue light with enhanced efficiency. The observation of spatially selective silver patterns on surface of the heterostructure after reaction suggests that photogenerated electrons and holes in ferroelectric BiFeO3 are driven in opposite directions to reduce their chance of recombination. Comparisons of the amounts of reduced silver on TiO2 film grains with distinct phases/orientations show that the reactivity is mildly preferential on anatase TiO2 phase and does not strongly depend on crystallographic orientation of BiFeO3.IntroductionTitania (TiO2) is capable of photocatalytically converting H2O to hydrogen and oxygen under the irradiation of ultraviolet light. [1, 2] One of the limiting factors for titania to be used as an effective photocatalyst is its band gap. Because the absorption edges of rutile and anatase titania are at 3.0 eV and 3.2 eV, respectively, they can only absorb light in the UV portion of the spectrum, which is about 3% of the available solar energy. [3-5] This limitation has motivated attempts to modify the absorption edge of titania so that it can absorb visible light.One strategy is to substitute a portion of the titanium and/or the oxygen with other atoms. There are numerous reports on visible light absorption of titania by doping and co-doping of Cr, V, Mo, Sb, Fe, N, S, C, and F. [6-34] Another strategy is to add an adsorbed molecular species that absorb visible light and donate an electron or hole to the titania, such as organic dyes [33, 35, 36] and Ce3+/Ce4+. [37, 38]The strategy in the present work takes the approach of depositing a pure titania thin film on a visible light absorbing substrate BiFeO3 to induce visible light activity of the heterostructure. BiFeO3 is a semiconductor with a band gap of about 2.5 eV [39-41] and is photocatalytically active in visible light. [42, 43] It is also ferroelectric with spontaneous polarization along pseudo-cubic <111> directions of 6.1 µC cm-2. [44] The spontaneous polarization gives rise to internal electric fields that drive photogenerated charge carriers, namely electrons and holes, in opposite directions to reduce their chance of recombination. [45-47] Additionally, the separation of electrons and holes leads to the spatial separation of reduction and oxidation half reactions so that the back reaction of intermediates is also suppressed. Such charge carrier separation has been reported in TiO2/BaTiO3 heterostructures with UV light illumination. [48-51] The TiO2/BiFeO3 heterostructures in this work combine both advantages of the relatively narrow band gap and the internal fields in BiFeO3 to enhance the overall photocatalytic activity."

Jan 1, 2014

By A. Varma

Successful technology commercialization occurs when a company is focused on creating shareholder value by providing a reliable product at a price point attractive to the market, while at the same time maintaining strict control of its internal cash burn rates. Developing a technology platform and a market platform are equally important in the commercialization of new technologies such as fuel cells. This paper will discuss some of the key barriers that may prevent successful market entry for emerging and disruptive technologies, such as: R&D priorities, supply chain / manufacturing issues, materials, cost reduction strategies, customer needs, developing a market pull strategy, institutional barriers such as existing regulatory/approvals processes and/or current design/purchasing practices, product reliability and resilience, and finding the right path to market. SDTC is an arms length foundation that aims to financially support the successful market entry of emerging and disruptive technologies that can provide significant environmental benefits to Canada. The fuel cell industry, which represents one such technology, is at a critical point in its evolution where market receptivity and the technology platform are converging to potentially create significant customer advantages for fuel cell products being developed today. Since its inception in 2001, SDTC has received over 850 business cases from which it has identified successful strategies to overcome the noted barriers to commercialization. While maintaining commercial confidentiality, the SDTC database will be mined to: Identify specific success stories that have overcome various barriers and discuss their strategy; Identify specific fuel cell related industry experiences that hinder successful market uptake. The general attributes and trends of successful technology developments identified in this paper will hopefully provide guidance to technology developers and prepare them to successfully tackle the next set of hurdles on the path to commercializing their technology, once they have proven their technology works in the laboratory.

Jan 1, 2005

By A. Lee Barrett

"THE COAL INDUSTRY of the United States• and Canada has made great progress in recent years. Coal mining in •the old days represented one of the most arduous tasks for labour and industry, but over the years great progress has been made in reducing the effort required from labour. Also, the tonnage produced per man, the cost of the coal per ton, and the overall safety of the operation, have been greatly improved.Looking back over the past fifty years:, the era can be divided into four principal parts: (a) hand-loading, (b) track mining methods, (c) off-track mining methods, and (d) continuous mining. For many years, all of the coal was won by hand-mining methods. The first forms of mechanization •resembled the move from the horse •and buggy to the automobile. Early track mechanical mining methods were usually adaptations of the direct methods involved in hand-mining, with each improvement directed toward some specific process. A revolutionary development came about with off-track mining methods. The first efforts in this direction were provided by off-track mechanical loading machines, which loaded the cars •on track and differed from conventional track mining methods only in that the loading machines themselves operated on the mine floor. With the advent -of the shuttle car about ten years ago, true off-track mining came into being, and real progress in this direction began to be made.At the present time we •are at the beginning of a new era -.the era of continuous mining. There will be a period of development with some time needed before the system is generally applied throughout the industry, but -already enough •has been done to indicate rather dearly what the future holds in this direction."

Jan 1, 1953

By Michel Dagbert

In the exploitation of porphyry-type deposits, the quality of the ore is mostly defined according to its grade. Besides the simplest distinction, ore-waste, several grade categories may exist and they correspond to the different ways in which the ore is further processed. At the time of mining the selection of the different categories is done from extensive information available from blast holes. But planning has to be done before this information is available and it is necessary for the geologist to forecast, from exploration and development data alone, the possible outcome of the selection done later on a block, a level, or the whole deposit and ultimately predict the ore reserves and value of the deposit. A good statement of this problem has been presented at the 1976 AIME annual meeting by Williamson and Hueller (1976). They have shown that, if the cut-off values are directly applied to the estimated grade of blocks, a gross overestimation of the recovered tonnage of ore (14%) will occur. This problem, now termed "the vanishing tons problem" (DaVid, 1977) seems to be common in many open-pit operations and it has been explained several times (DaVid, 1972; Huijbregts, 1975). In order to solve it l.Jilliamson and Mueller proposed a solution based on compiling masses and masses of blast hole data available from mined-out portions of the deposit. They derived empirical correction factors which provide for every block, given its estimated grade, the expected tonnage and average -grade of each category of material within that block. The purpose of our work is to repeat the same exercise but ignoring the blast holes data i.e. we want to derive the correction factors from the only DOH data. Doing this, we are more in the real conditions where the valuation of the mine and are reserve analysis has to be made before production actually starts. Two possible ways to achieve this goal will be investigated and the emphasis will be on recently

Jan 1, 1977

By D. R. Nagaraj

The traditional (popular) approach to reagent development and optimization, which has become entrenched in both research and practice for many decades, is highly reductionistic, incremental and costly, does not produce robust chemical solutions, and is not sustainable. There are also several other key drivers and changes in the mineral industry that clearly warrant a new approach. In response to these, an intense effort was made at Cytec over the past fifteen years to develop a meaningful, efficient, and sustainable approach to develop new reagents and robust chemical solutions in mineral separations. This effort culminated in three important outcomes: a) development of the holistic approach, called FLOTATION MATRIX 100? process, b) novel reagents, and c) enhanced application knowledge for reagents. In this paper, the efficiency, utility and power of the holistic approach will be demonstrated with examples using both existing and new reagents in the processing of Cu-Au, Au and Cu-Mo ores.

Jan 1, 2014

By J A. van Niekerk, J G. Jardine, J W. Olivier

The Runruno Gold Project is located on the island of Luzon, approximately 200 miles north of Manilla in the Philippines. The mine is an open cut operation and uses the proven BIOX&#174; and carbon-in-leach (CIL) processes to recover gold, and the ASTER™ process for detoxification of the CIL residue prior to discharge to the Residue Storage Impoundment (RSI). Work to date has defined a mineral resource of 1.39 million ounces (Moz) of gold, and the operation will produce 96 700 oz of gold per annum over a mine life of 10.4 years. The BIOX circuit is designed to treat 140 000 t/y of concentrate with a design capacity of 404 t/d of concentrate at a design sulfide sulfur grade of 17% S2-.The Runruno BIOX Plant is the first application of the Outotec BIOX Generation III design principles, focussing on ease of operation and maintainability. During development and implementation, the project team focussed on identifying opportunities to optimise the capital efficiency while not compromising on the operability or overall efficiency of the process or the equipment. The BIOX plant also incorporates the latest developments in the design of the BIOX agitators for more efficient mixing and gas dispersion. This paper will discuss some of the critical aspects and decisions taken during the development and implementation of the BIOX Process at the Runruno Gold Project. The paper will highlight some of the factors affecting the commissioning process as well as the improvements seen through the introduction of the Generation III BIOX design principles. CITATION:van Niekerk, J A, Olivier, J W and Jardine, J G, 2017. Implementation of the BIOX&#174; process at the Runruno Gold project, in Proceedings MetPlant 2017, pp 218–228 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By Kourosh Shahriar, Kazem Oraee, Ezzeddin Bakhtavar

"In this paper, a relationship between dependant parameters and the crown pillar thickness is first introduced. This relationship defines geotechnical problems caused by thin pillars and economic considerations created by pillars that are thicker than the optimum size. For this purpose, a dimensional analysis as an effective physico-mathematical tool was used. This technique restructures the original dimensional variables of a problem into a set of dimensionless products using the constraints imposed upon them by their dimensions. A model is hence introduced that calculates the optimum pillar thickness. The relationship introduced here and the method applied can be used by mining engineers in all situations where a combined open-pit and block caving method is deemed to be the most appropriate mining method.INTRODUCTIONMany deposits can be mined entirely with the open-pit method; others must be worked underground from the very beginning. In addition, there are the near-surface deposits with considerable vertical extent. Although they are initially exploited by the open pit method, there is often a ""transition depth"" where decision has to be made about changing to underground methods.Some of the biggest open-pit mines worldwide will reach their final pit limits in the next 10 to 15 years. Furthermore, there are many mines planning to change from open-pit to underground mining due to increasing extraction depths and environmental requirements. In this way, it is likely that block and/or panel caving will enable the operations to continue achieving a high production rate at low costs as an underground method (Bakhtavar et al., 2009).In these cases, it is often necessary to consider a crown pillar beneath the transition depth (open-pit floor) before starting an underground caving stope method (Figure 1).There are generally two kinds of crown pillar: a ""surface crown pillar"" and ""crown pillar between open-pit and underground mining."" In general, they both play the similar role in mining. Since the primary purpose of a surface crown pillar is to protect surface land users, the mine, and those working in it from inflows of water, soil, and rock; it is vital that the surface crown pillars remain stable throughout their life. When a crown pillar could potentially remain between open-pit and underground mining it is specially proposed to prevent water entering from the open-pit floor into the stope, as well as to reduce open-pit wall and floor caving."

Jan 1, 2010

By G. L. Oldright

This paper is the first of a series that is to appear on smelting in the lead blast furnace. The objects of this investigation are to determine the conditions obtaining within the blast furnace by direct experimentation, and to correlate the behavior of the furnace at various times with the main factors governing the operation of the blast furnace, and metallurgical losses. ACKNOWLEDGMENTS The writers wish to express their appreciation to the management of the International Smelting Co. at Tooele, Utah, to Mr. J. O. Elton, the general manager, and to Mr. A. B. Young, his assistant, for their broad-gauge policy that has made possible the securing and publishing of these data. For the staff at Tooele, acknowledgments are made to Messrs. B. L. Sackett, general superintendent, Carlos Bardwell, assistant general superintendent, S. Jacobsen, blast-furnace superintendent, H. M. Rockwell, assistant blast furnace superintendent, and J. O. Welsh, superintendent of the general research, for the spirit of cooperation they manifested in carrying out this work. Mr. C. Reish, a member of the research department, was detailed by, the company to assist in this&apos; work and his whole-hearted assistance has been found invaluable.

Jan 1, 1929

By Michael J. Friedel

The scale-dependent hydraulic properties in a fractured porphyry copper oxide deposit are investigated for relevance to in situ leach mine (ISLM) design. In most well field designs, mine operators assume that hydraulic properties represent a continuous spatial function, or continuum. The problem, however, is that the representative elemental volume, the volume over which hydraulic properties are described as a continuum, is a domain (if it exists) that occurs between end members representing varying degrees of heterogeneity. At the Cyprus Cas a Grande mine, transmissivity fluctuations are spatially correlated suggesting that at the scale of ISLM, the hydraulic process is heterogeneous and a typical continuum representation is inappropriate for design. Alternatively, a conditional stochastic approach using the simulated annealing (SA) technique is deemed useful for the imaging of heterogeneous hydraulic properties. Specifically, SA preserves transmissivity extremes and spatial complexity, both necessary for accurate conditioning of a flow simulator. Also, the stochastic continuum approach provides an avenue whereby uncertainty (or risk) may be addressed. Currently, the SA weaknesses are that it is computationally time consuming, and uncertainty may increase when simulating under conditions of statistical isotropy. Recognizing that ISLM exerts a dynamic influence on hydraulic properties with time, the mine design should be reevaluated at intervals throughout the evolution of the leaching process.

Jan 1, 1993

By S. Chander

The effect of sample storage in argon and in air on kinetics of oxidation of pyrite from a coal source was studied using accelerated weathering test in laboratory columns. Prior to the weathering tests the samples were crushed, ground, and stored for various time periods in argon and air. The results showed a dramatic difference in the rate of oxidation of the aged samples. The differences were interpreted based on the hypothesis that the aging of pyrite led to the formation of surface coatings which changed with time. The significance of these results in pyrite/reagent interactions in flotation and in evaluating the acid mine drainage potential of pyritic waste materials is discussed.

Jan 1, 1993

By J. E. Castle

The essential foundation upon which to build an effective marketing program in industrial minerals is the ability to produce competitively mineral products meeting precise customer specifications and to ship them promptly and on schedule. Without this prerequisite, all the other factors in a second marketing program-creative sales management, energetic solicitation, advertising, technical service, new products, etc.are without meaning. The primary image to be created in the mind of customers is that of the reliable and prompt supplier of mineral products at competitive prices and of standard, uniform quality. With this favorable image implanted, it becomes possible to integrate the other essential factors into a strong marketing program; and without this image, little can be accomplished. After having .made provision for the basic product ion position outlined, there are then two fundamental considerations in the design of a successful marketing program for industrial minerals. The first of these is that the number of potential customers for the typical industrial mineral product is, relatively small, and indeed compared to the number of customers for consumer products, the number is actually minute. The second consideration is that the customers for industrial minerals are manufacturers and producers rather than consumers. These two factors lead to a necessity that the marketing program be specifically and uniquely tailored to fit the individual mineral product to be sold and to conform to an existing pattern of distribution.

Jan 1, 1962

By Jennifer Murphy, Brad S. Schake, Karol Holmes, John R. FitzPatrick, Mike H. West

"The separation and purification of uranium from either nitric acid or hydrochloric acid media can be accomplished by using either solvent extraction or ion-exchange. Over the past two years at Los Alamos, emerging programs are focused on recapturing the expertise required to do limited, small-quantity processing of enriched uranium. During this period of time, we have been investigating ion-exchange as a method for extraction/purification of uranium from acidic media. In addition, waste stream polishing is associated with this effort in order to achieve more complete removal of the uranium prior to recycle of the acid. Extraction chromatography has been demonstrated to further polish the uranium from both nitric and hydrochloric acid media thus allowing for a more complete recovery of the actinide material and creation of less waste during the processing steps.We will discuss contact experiments for evaluation of eleven different resins for uranium removal from nitric acid, the evaluation (again by contact experiments) of uranium elution from the ion-exchange media by various chemicals, and small-scale experiments for the removal of 235U from nitric acid. Larger-scale (1 DO-gram) flow experiments, using depleted uranium, were done after the small-scale evaluation of the selected resin. A discussion is also included concerning the shortcomings of the contact experiments and how the flow experiments were modified in order to overcome these problems. We will also discuss the application of ion-exchange for some specific process needs at Los Alamos.Contact experiments were used to evaluate some commercially available solvent-impregnated resins in addition to evaluation of several resins of this type synthesized in our laboratory. These experiments involved both nitric and hydrochloric acid media. The data from these experiments will be used to determine the column size and amount of resin required to polish the waste stream produced by the ion-exchange process described above. Small-scale flow experiments will be described and data given on the mass balances achieved using this two step process.Future work for evaluation of new ion-exchange and solvent-impregnated resins as well as the search for new eluants will be discussed. Other future experiments for both processes, including large-scale experiments, will be discussed in detail."

Jan 1, 1996

By T. T. Read, T. L. Joseph, F. H. Royster

In a preliminary study of the beneficiation of iron ores conducted by the Bureau of Mines, one of the authors (T. T. Read) found it necessary to ascertain, if possible, how much effect a decrease in the silica content of an iron ore has upon the cost of making pig iron from the ore. In the beneficiation of iron ores the most important impurity to be removed is usually silica, and the amount that can be expended on a beneficiation process to reduce the silica content of the ore is obviously determined by the amount of increase in the value of the ore after beneficiation. The price that can actually be obtained for a beneficiated ore is, of course, a matter of negotiation between the seller and the buyer, but since the relative value of different grades of iron ore must be chiefly based upon the cost of making pig iron from them, an approximation as to the effect which decrease in the silica content of ore has upon the cost of snaking pig iron is an important guide in estimating what probable average gain will result from subjecting an ore to a beneficiation process. A search of the literature failed to reveal any detailed statement on this important topic, but fortunately the data are at hand to permit making an approximate calculation of the probable effect. For the purpose of the calculation assume three iron ores with the following composition (natural):

Jan 1, 1924