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By Y. J. Son, S. S. Nageshwaraniyer, K. M. Kim

"This paper reports on the development of a simulation-based framework for obtaining optimal blast design parameters for a hard-rock mine. To do this, a conventional medium-sized hard-rock mine was taken as a case study. The mine has two pits containing hard and soft rock types. The proposed framework contains a combination of regression analysis using Excel software by Microsoft and discrete-event simulation using Arena software by Rockwell Automation, applied to construct a model of the material-handling network of the mine. Specifically, blasting parameters are estimated by Excel-based regression analysis, processes including blasting and haulage from pits to crushers are modeled by a Forward Blasting simulation submodel, and material-handling operations including crushing, storage in stockpile, and haulage via conveyors and into SAG and ball mills are modeled by a Crusher to Ball Mill simulation submodel. A Reverse Blasting submodel is then used to obtain the optimum blast design corresponding to a target P80 particle size. Using the proposed framework, an economic analysis was performed to demonstrate the cost savings that could be realized for each rock type as a function of specific explosive energy. IntroductionIn a modern hard-rock mine, various processes such as drilling, blasting, crushing, grinding and mineral liberation are optimized to increase productivity, a practice known as mine-to-mill (MTM) optimization. Blasting is important in MTM optimization as it is the first comminution process and has an impact on all downstream processes (Julius Kruttschnitt Mineral Research Centre, 1996; Nielsen and Lownds, 1997; Nielsen and Malvik, 1999; Chung and Katsabanis, 2000; Kim and Kemeny, 2011a; Kim and Kemeny, 2011b).Two main research topics have emerged in the area of blasting design: (1) identifying the optimal target blast fragmentation at each shot and (2) controlling the blast fragmentation for that target. As part of an MTM optimization study, Kim and Kemeny (2011a; 2011b) developed a site-specific blast fragmentation prediction model that can be used to identify the target blast fragmentation and can be incorporated into MTM optimization. They also reported methodology for assigning model parameters easily and with minimal human bias."

Jan 1, 2015

By Gregg A. Swayre, Roger N. Clark, Stephen J. Sutley, Kathleen S. Smith

Imaging spectroscopy is a relatively new remote sensing tool that provides a rapid method to screen entire mining districts for potential sources of surface acid drainage. An imaging spectrometer known as the Airborne Visible/InfraRed Imaging Spectrometer (AVIRIS) measures light reflected from the surface in 224 spectral channels from 0.4 - 2.5 µm. Spectral data from this instrument were used to evaluate mine waste at the California Gulch Superfluid Site near Leadville, Colorado. Here, the process of pyrite oxidation at the surface produces acidic water that is gradually neutralized as it drains away from mine waste, depositing a central jarosite zone surrounded by a jarosite + goethite zone, in turn surrounded by a goethite zone with a discontinuous hematite rim zone. Leaching tests show that pH is most acidic in the jarosite and jarosite + goethite zones and is near-neutral in the goethite zone. Measurements indicate that metals leach from minerals and amorphous materials in the jarosite + goethite and jarosite zones at concentrations 10 - 50 times higher than from goethite zone minerals. Goethite zones that fully encircle mine waste may indicate some attenuation of leachate metals and thus reduced metal loading to streams. The potential for impact by acidic drainage is highest where streams intersect the jarosite and jarosite + goethite zones. In these areas, metal-rich acidic dace runoff may flow directly into streams. The U.S. Environmental Protection Agency estimates (U.S. EPA, 1998) that mineral maps made from AVIRIS data at Leadville have accelerated remediation efforts by two years and saved over $2 million in cleanup costs.

Jan 1, 2000

By A. E. Isaacson

The U.S. Bureau of Mines determined the effect of common sulfide minerals on the corrosion rates of various types of ferrous alloy grinding media. Data obtained from this study will aid in determining the contribution of any electrochemical reactions between sulfide minerals and grinding media to the total grinding media consumption. Common sulfide minerals used in this study were chalcopyrite, galena, and sphalerite. In the presence of oxygen, chalcopyrite was found to increase the corrosion rate, galena was found to decrease the corrosion rate, and the effect of sphalerite was dependent upon the type of grinding media. Possible electrochemical reactions of these minerals in the presence of grinding media are suggested.

Jan 1, 1989

By P. deH. Eastcott

The paper summarizes a slide presentation made during the CIM Mechanical-Electrical Operators' Conference, held at Sudbury. Ontario, January 25-27, 1977. Its scope has been limited to a few specific aspects of modern Canadian hoisting plant practice that are likely to be of interest to operating personnel. It is intended to serve as a brief review of established methods discuss in more detail the present state-of-the-art and suggest trends that will appear as products during the next few years.

Jan 1, 1977

By Donald B. Buddecke

The large walking dragline has been the most commonly used overburden-stripping equipment in Texas lignite mines. These draglines, operating on the highwall side of the pit, can excavate to a depth of 45 m. Considerable overburden rehandling is required beyond 30 m and may reach 100 percent by 45m. As pit depth increases, dragline operation also becomes more complex, with two or three passes being necessary to make a cut 30 to 40 m wide. Multiseam operations also require extra passes. At pit depths greater than 45 m, the dragline must be operated also from a spoil bench. This can be difficult in the unstable alluvial deposits in which lignite occurs.

Jan 1, 1985

By Karl J. C. Harries

"11.1. INTRODUCTIONA royalty is the most common form of interest retained by an owner who is disposing of his property or by a joint venturer who ceases, voluntarily or otherwise, to participate in the joint venture.1 Rarely does a non-participating party have a direct interest in the property and/or assets of a project, except during the period when a non-participating joint venturer may be having his interest diluted.2 In fact, it is most unwise to permit a non-participating party to have such an interest. It may give rise to significant problems that could prevent or substantially delay the development of an orebody and require a considerable amount of time, effort, and money to correct.3In negotiating a royalty, it is important to be aware that there is no law or convention that says, “You just don’t do that in a royalty agreement.” As with any agreement, inventiveness and flexibility on the part of the negotiator are not just assets, but virtual necessities. It is also for this reason that it is essential to read the royalty provisions, particularly the definitions, fully and carefully, especially if you are the recipient. On the other hand, if your inventiveness and flexibility cause your accountant to question the advisability of one of your ideas, pay close attention to him.4 He will, no doubt, have had experience with many royalties, and no competent professional adviser disparages a client’s ideas without good reason. Besides, he will probably be the person who will be determining the royalty or certifying the determination of it. At the very least, he will be auditing your general financial statements, which must, of course, reflect the royalty determination. Heeding his advice not only may make the determination easier but also will probably save you money in professional fees later on. Nevertheless, do not simply accept his comments or recommendations without understanding what they mean, why they have been made with respect to your royalty agreement (sometimes professionals have comments that they make as a matter of course and, even though they may be valid, you should require them to be justified to you), and how they will affect your royalty determination.It is surprising how many corporate payors insist that their standard royalty provisions5 be used as a matter of policy, thereby effectively tying the negotiator’s hands. It is even more surprising, and to professional advisers frightening, how many of the senior employees who insist that such a policy be adhered to, virtually without variation, do not know what is in the standard provisions and would be hard-pressed to explain them to a property owner. If standard provisions are appropriate, by all means use them, but do allow experienced and sensible negotiators some flexibility and make sure that everyone within the corporation who may have to use such provisions – negotiator and supervisor alike – knows what they contain and why they are as they are. For example, there are often good and convincing reasons to describe a deduction in a certain way or to include a certain specific type of deduction. On the other hand, quite often the answer to the question “why?” is that “it has always been there”; this is, or should be, an unacceptable answer. In any event, if you, as the negotiator, appear to know what you are talking about, are familiar and comfortable with your royalty provisions, and are backed up by your boss with the same words or reasoning, a property owner cannot help but be satisfied that you are knowledgeable, even if he still does not agree with your provisions. Finally, if you do use standard provisions, make sure that they are reviewed and updated regularly."

Jan 1, 2003

By Enrique Touceda

For a number of years prior to the world war, the firm of Geo. H. Thacher & Co., of Albany, N. Y., was engaged in the manufacture of marine and other gray-iron castings. At the outbreak of the war the firm decided to specialize in the manufacture of propeller wheels. It attacked the problem, therefore, from a foundry point of view, seeking to produce a casting that would be so accurate that no subsequent machining would be required on the blades, also from the point of view of the ship builder. There were two general methods of manufacture, the shortcomings of which have been freely acknowledged. In the sweep method, the nowel, or bottom half-mold, for each blade is swept up by a spindle beam and pitch race, while the top half-mold for each blade is built up individually. In the pattern method one individual blade, with the hub or hub portion, is mounted on a spindle and the individual blade mold formed, the pattern is then rotated on the spindle to the position for the next blade, etc. In rare cases wheels were made from a solid pattern. Owing to the cost of the pattern, its failure in many instances to be correctly made, and (when made of wood) its early and sure distortion the disadvantage of this pratctice is obvious, while metal patterns in most instances were prohibitive in cost. In these methods both green-sand and loam molding was practiced. The casting produced by either method can be considered only as a blank from which the propeller must be machined. The back surface of each blade must be chipped to the templet and through this procedure chipped to such accuracy as will be required for a static balance. Inasmuch as the work done by the machine tool is confined to the driving face of the blades, not only is perfection most difficult, but corrosion will be greater because of the removal of the dense skin of the casting and the local strains set up by the pneumatic tool in chipping. To produce a finished 9-ft. propeller for a Navy destroyer required from 8 to 21 days of foundry work and about the same length of time for the machining. Through the use of the Thacher process, only as many hours are required, besides it is possible to produce a finished casting in perfect conformity with any particular propeller-wheel design.

Jan 1, 1922

By Henry Mulryan

THE largest and purest known deposit of diatomite is being actively mined and processed 3 ½ miles south of Lompoc, Santa Barbara County, Calif., by the Johns-Manville Products Corporation. The workings FIG. 1-LOCATION OF DIATOMITE DEPOSIT AT LOMPOC. cover 4000 acres, the depth of economically recoverable diatomite being 1000 ft. (Fig. 1). Lompoc, a community of 2500 population, is situated in the Santa Ynez River Valley 10 miles inland from the Pacific Ocean. It is 44 miles

Jan 1, 1936

By Enrique Touceda

For a number of years prior to the world war, the firm of Geo. H. Thacher & Co., of Albany, N. Y., was engaged in the manufacture of marine and other gray-iron castings. At the outbreak of the war the firm decided to specialize in the manufacture of propeller wheels. It attacked the problem, therefore, from a foundry point of view, seeking to produce a casting that would be so accurate that no subsequent machining would be required on the blades, also from the point of view of the ship builder. There were two general methods of manufacture, the shortcomings of which have been freely acknowledged. In the sweep method, the nowel, or bottom half-mold, for each blade is swept up by a spindle beam and pitch race, while the top half-mold for each blade is built up individually. In the pattern method one individual blade, with the hub or hub portion, is mounted on a spindle and the individual blade mold formed, the pattern is then rotated on the spindle to the position for the next blade, etc. In rare cases wheels were made from a solid pattern. Owing to the cost of the pattern, its failure in many instances to be correctly made, and (when made of wood) its early and sure distortion the disadvantage of this pratctice is obvious, while metal patterns in most instances were prohibitive in cost. In these methods both green-sand and loam molding was practiced. The casting produced by either method can be considered only as a blank from which the propeller must be machined. The back surface of each blade must be chipped to the templet and through this procedure chipped to such accuracy as will be required for a static balance. Inasmuch as the work done by the machine tool is confined to the driving face of the blades, not only is perfection most difficult, but corrosion will be greater because of the removal of the dense skin of the casting and the local strains set up by the pneumatic tool in chipping. To produce a finished 9-ft. propeller for a Navy destroyer required from 8 to 21 days of foundry work and about the same length of time for the machining. Through the use of the Thacher process, only as many hours are required, besides it is possible to produce a finished casting in perfect conformity with any particular propeller-wheel design.

Jan 1, 1922

By Venugopal B, M Kumaran, Thomas John, Vetriselvan A

The initial pile load tests are conducted to ensure the geotechnical capacity of the pile in a particular site condition. Normally kentledge method is adopted for the compression pile load tests. In this method the entire kentledge load is loaded above secondary beams which are supported by concrete blocks above the Natural Ground Level. So, it is important to ensure the SBC (for shear and settlement) of the natural ground. In one of our projects initially it was decided to go with kentledge system for initial compression load test on 56m long 1200mm diameter BCIS pile. The test load and total kentledge load were 2160t and 2700t, respectively. The soil strata mainly consisted of clay with low SPT N value and water table almost at ground level. It was suggested to replace top soil using Granular Sub-base (GSB) with good compaction in order to avoid excessive settlement of concrete blocks placed to support the kentledge weight. When the kentledge loading started, even before reaching 10% of total kentledge load, excessive settlement on the GSB layer was observed. This paper describes the problems faced during normal kentledge method and how it was overcome using the liner pile system for initial compression load tests in this particular site condition for higher test load.

Nov 1, 2022

By Felipe De Lucio Pezet

El presente texto señala las formas más eficaces de producción, donde no haya mayor consumo de mano de obra con menor incidencia directa en el tonelaje minado. Por ello, la modificación de las operaciones (mantenimiento de labores de acceso, avance en chimeneas; relleno; desarrollo de minas), conlleva un mejor productividad. Asimismo, la transferencia de tareas de operaciones no directamente ligadas a la producción hacia operaciones directamente productivas, permite un mejor uso de la fuerza laboral y reduce el costo de producción y aumenta la productividad.

Nov 1, 1972

By D. M. Thayer

Dry magnetic separation of feebly magnetic minerals and wet magnetic separators suitable for highly magnetic minerals have been commercially utilized for a number of years. The beneficiation of magnetic taconite ores by conventional, low intensity magnetic separators in combination with flotation is well established technology (1). However, over the past decade much effort has been expended in developing techniques for the upgrading of feebly magnetic oxidized iron ores (2,5). Such research and development have been stimulated by the limitations of the above-mentioned techniques in application to ores containing fine material; for example, ores requiring fine grinding for liberation or slime-forming ores such as the oxidized taconites or semi-taconites. Wet separation has allowed the reduction of the minim particle size that can be effectively treated from that allowable for high intensity dry magnetic separation. Consequently, the development of high intensity wet magnetic separation methods has received much attention in the search for an effective method to treat the weakly magnetic minerals. Recently Lawver and Hopstock (5) have provided an excellent review of the state of know- ledge of this technology. In addition, a valuable compendium of available laboratory and commercial devices is included. Nonetheless, the feasibility of the use of high intensity magnetic separation in a particular application is largly empirical in nature and requires experimentation to chazacterize the response of a particular ore. The purpose of this paper is to assess the incorporation of high intensity magnetic separation for the beneficiation of a non- sliming specular Michigan hematite. Particular attention is focused on the existence of a lower limit of particle size that can be treated effectively and is inherent in the use of these techniques. Additionally, a rationalization of various models presented in the literature is attempted.

Jan 1, 1979

By William G. Doepken

GENERAL DESCRIPTION The Henderson mine utilizes a highly mechanized, continuous panel-caving system to extract ore from a deep, massive, molybdenum deposit. The mine site, lo¬cated 80.5 km (50 miles) west of Denver, is situated at 3170 m (10,400 ft) above sea level in a steep valley on the eastern side of the Continental Divide. The mill site, located on the western side of the divide, is linked to the mine via a 15.5-km (9.6-mile) railroad tunnel. Mine production is scheduled to reach 27 215 t/ d (30,000 stpd) from the uppermost production level. This pro¬duction rate will have been reached within the four years following an intensive ten-year preproduction development program. A second production level, due to come on stream in later years, will expand production capabilities to 31 751 t/d (35,000 stpd). The mine, which employs approximately 2000, has blocked-out ore reserves of 220 Mt (242 million st) at an average grade of 0.42% MoS2. Geology The Henderson deposit is composed of two partially overlapping ore bodies that lie 1080 m (3600 ft) beneath the peak of Red Mountain. The ore bodies are entirely within a Tertiary rhyolite porphyry intrusive complex that has intruded Precambrian granite. The de¬posit is elliptical in plan with overall dimensions of 670 x 910 m (2200 x 3000 ft). In section it is arcuate with an average thickness of 185 m (600 ft). The top of the deposit is at an elevation of 2610 m (8700 ft) while the lower limits range from 2340 m (7800 ft) on the west to below 2100 m (7000 ft) on the east. The mineralization is relatively continuous in the ore bodies and consists of molybdenite and quartz in random to subrandom, intersecting, closely spaced veinlets. Cavability RQD (rock quality designation) * values measured from Henderson drill core and compared with the RQD values from the Climax and Urad block-cave mines in¬dicated that the Henderson ore would cave but with difficulty and that a high percentage of the cave ma¬terial would be blocky. Initial caving experience shows the Henderson ore caves easier and with greater frag¬mentation than was indicated by the RQD values. Pos¬sible reasons for this are: 1) The greater lithostatic load at the Henderson has a greater effect on caving and fragmentation than anticipated. 2) The relief of confining pressure due to caving action and brittleness of the rock is enhancing breakage. Mine Layout The Henderson mine layout was designed from its inception for a large-scale, rubber-tired, continuous panel-caving mining system. The ore body is vertically divided into three major mine levels (Fig. 1). The top¬most level (8100 level), which is 2469 m (8100 ft) above sea level, is the current mine production level. The intermediate or 7700 level, which is in the initial

Jan 1, 1982

By Rodríguez V. Raymundo E.

El presente trabajo describe la evaluación del uso de brocas tricónicas como herramientas principales de perforación en el yacimiento minero de Cerro Verde, Arequipa. La óptima utilización de esta herramienta representa el 30% de los costos totales de perforación, los cuales se ven reflejados en los factores de análisis a considerar para la superación de performances y las perspectivas que se aplicarán en el futuro para alcanzar mejores rendimientos y bajar los costos de perforación.

Oct 14, 1980

As the mining sector increasingly embraces the sustainability agenda, and implements thorough environmental reporting in support of its case for a continued æsocial licence to operateÆ, there is a need for ever-clearer metrics for key areas of impact. It is clear that natural waters are both the predominant pathway and main recipient of the environmental impacts of mining. A new approach to summarising the impacts of mining operations on water quantity and quality is proposed, adapted from an existing generic framework, which is increasingly used to quantify the æwater footprintsÆ of cities and nations. This includes both direct water use and ævirtual waterÆ use, implicit in goods and services used by the mine. In contrast to the existing formulation of æwater footprintÆ, it is here argued that it makes hydrological sense to express the water footprints of mines in areal terms, as equivalent catchment areas. It is also important in the mining sector to capture systematic changes in the scale of impact, which can be anticipated and predictively quantified over the full life cycle. This includes the essentially infinite post-closure phase, during which æremanent water consumptionÆ occurs, either through physical water loss (eg by evaporation from pit lakes) or by ongoing contamination of sizeable flows of natural waters. Methods for assessing the water footprints of mines are now available, and the time is increasingly ripe for them to be applied in earnest in environmental reporting. An example application to a mine in a humid subtropical area of South America is presented. In that case, the mine site itself extended over 106 ha, whereas the maximum water footprint exceeded this by a factor of 27. Although the water footprint can be expected to decline by a factor of ten immediately after closure, sustained evaporation from pit lakes and tailings dams with water covers will gradually increase the remanent water consumption rate, such that the final post-closure water footprint remains about 25 per cent of that encountered during the peak of mining.

Jan 1, 2006

By F. Habashi

Chile is at present the largest copper and rhenium producer and was before World War I the largest nitrate producer. She is also an important producer of lithium carbonate and molybdenum oxide. An important event in the history of the country is the Pacific War of 1879-1883 in which she acquired the northern provinces initially belonged to Bolivia and Peru. In 1888 Chile annexed Easter Island. The Chilean mineral and cultural history is briefly reviewed together with the people who contributed to her development. The present report is the result of a number of academic and industrial visits to Chile during the period 1992 to 2009.

Jan 1, 2011

By Warren C. Gerler

An overland belt conveyor system is installed for only one reason to save money. It must pay its way on a ton-mile basis over a stated period of time, and do so in competition with other forms of transportation. Such a system with its economies has recently been installed at Simco-Peabody's mine near Coshocton, Ohio by Link-Belt Company. Three miles in length, this system carries coal from open pit and underground mining facilities to the Conesville Power Plant of Columbus & Southern Ohio Electric Company. The coal was formerly trucked from the mine direct to the power plant; but over the years the mining operations have moved progressively farther and farther from the plant, making the over-the-road hauling distance correspondingly greater. Simco-Peabody has mining operations over a considerable area just east of the Conesville Station. The majority of the coal is recovered by conventional strip mining. Some underground mining` is performed by the high wall method.

Jan 1, 1963

By T. Johnson, K. Lambrych, D. Kelley

Materials for construction of equipment used in hydrometallurgical plants are selected based on a combination of their ability to perform as required in aggressive process environments as well as their cost. As a material of construction, fiber reinforced plastic (FRP) has been shown to provide equal if not improved durability relative to alternative materials such as corrosion resistant alloys at a considerably lower cost. This is particularly true in the case of equipment used in acid leaching processes for copper, cobalt, nickel and rare earth elements. The selection and extensive use of FRP over alloys in new hydromet plant construction in North and South America illustrates this advantage of FRP effectively. This paper will compare corrosion performance and cost of plant equipment fabricated with stainless steel alloys and FRP made with Epoxy Vinyl Ester thermoset resins. Real world case histories for FRP piping, storage tanks, extraction vessels, and electrowinning cells combined with laboratory based corrosion studies will be reviewed to demonstrate how FRP materials are selected for hydrometallurgical equipment.

Jan 1, 2015

By N. A. Sareyed-Dim

Nickel ores may be classified into two major categories : sulphide ores, and oxidized lateritic ores, these latter containing nearly 80% of the known reserves of the metal (1). Two types of lateritic ores are recognized; ores high in iron but low in magnesia and silica are known as "limonitic", while ores low in iron but containing high percentages of magnesia and silica are called "silicate" (see Table I). Sulphide ores can be beneficiated readily by conventional ore dressing techniques and the technology for nickel recovery from such ores has been well tested in a number of commercial processes (1-4). Unfortunately, no economically viable process for the concentration of nickel from low-grade deposits has yet been developed, and so only the high grade ores are able to be worked profitably. Silicate ores have been treated pyrometallurgically for the production of ferronickel (2) (3) (5); limonitic ores have been processed hydrometallurgically to produce nickel metal (2) (3) (6) (7).

Jan 1, 1975

By E. Krause, V. G. Papangelakis, S. Garg, R. Mahadevan, E. Edwards

"Bioleaching uses iron and sulfur-oxidizing bacteria to extract base metals from sulfide minerals. As bioleaching involves breaking the iron-sulfur bonds by ferric attack, the biologically mediated rate of iron oxidation is recognized to play a key role in influencing the overall kinetics. In this study, we investigate the catalytic ability of an indigenous AMD culture for oxidizing Fe(II) in solution. This culture was subsequently adapted on pyrrhotite tailings (0.6% Ni) by gradually increasing the solids loading. Results from this study show that such an adaptation reduces the initial lag phase in the biotic oxidation of Fe(II), thereby allowing for a higher Ni extraction when compared to experiments with an un-adapted culture at a similar solids loading. The use of adapted cultures also helps to reduce the residence time for bioleaching of Ni from pyrrhotite tailings. INTRODUCTIONAs the world demand for pure base metals grows; the mining industry is increasingly faced with the burden of processing lower grade ores and mining waste streams in order to recover the occluded metal VALUES ((Watling, 2006). The extractive metallurgy of nickel from sulfide minerals focuses on using a combination of mineral processing, pyrometallurgical (smelting) and hydrometallurgical techniques to extract Ni from its ore bodies.Pyrrhotite (Fe1-xS) is commonly found in association with pentlandite and chalcopyrite in sulfidic Ni ores, such as those found in Sudbury, Ontario, and in Russia, e.g. Norilsk. The vast majority of this pyrrhotite needs to be removed using mineral processing techniques, in order to minimize the Fe and S contents of the concentrates that proceed on to smelting. If all pyrrhotite were left in the concentrate, much more slag and SO2 would be produced, and the smelter throughput would be limited. Beneficiation of Ni sulfide ores leads to the rejection of unwanted constituents as mining wastes, which may still contain extractable amounts of Ni (Edgar Peek et al., 2010)."

Jan 1, 2012