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By P Wahyono, H Vega, S Riza, P Vergara, P Gonzalez-Carbonell

PT Freeport Indonesia (PTFI), operating in the Ertsberg Mining District in the Province of Papua, is developing the Grasberg Block Cave copper-gold mine. The site aims to output 160 000 t/d and will be located underneath the current Grasberg Open Pit. Initial studies of the potential to develop a block cave mine in the Grasberg orebody have revealed that the mine will require significant volumes of air. The Grasberg Block Cave (GBC) project requires four primary fans (3750 kW each) to support production at full capacity.Fan #1 commissioning was accomplished successfully on 9 February 2012. However, Fan #2 chamber, which is separated by a 20 m pillar, had not been completed. The main challenge was Fan #2 chamber still needed to be benched. The risk of damage to the critical infrastructure in Fan #1 chamber, including ground support, cracks in pedestals, and misalignment in the impeller shaft were considered. The challenges were blasting the bench without damaging the surrounding infrastructure, completing the work safely and meeting the schedule. This was achieved with the engineering control methodology. This paper summarises the benching process of Fan #2 chamber and its impact upon Fan #1.CITATION:Vega, H, Riza, S, Gonzalez-Carbonell, P, Wahyono, P and Vergara, P, 2013. Excavating an underground primary fan chamber that is adjacent to a fully operational primary fan in PT Freeport Indonesia's Grasberg Block Cave Mine, in Proceedings The Australian Mine Ventilation Conference , pp 115-122 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Hanry Guillén

En la Compañía Minera KOLPA, se analizó el comportamiento de sus operaciones unitarias por el período Marzo - Agosto 2016, en el cual se identificaron procesos asociados a los ciclos de perforación y voladura, bajo los términos de variabilidad NO ESTABLES NI SOSTENIBLES, los mismos que ameritaban medirlos, analizarlos, mejorarlos y controlarlos a fin de adoptar decisiones que conduzcan a operar la mina en términos de calidad y excelencia.

Sep 1, 2017

By J. Robison, H. Pieterse, C. C. Smith, M. Luque, S. Chipman

Phase change during pressure let down releases significant amounts of energy that must be controlled to avoid undo wear and tear on equipment. Hydrometallurgical slurries require flow control equipment (valves and tanks) made of expensive materials to withstand the abrasive, and often corrosive nature of the slurry. Presented is a model of the nozzle of a let-down choke which is designed to control the flow pattern that exits the choke (valve) as it enters the receiving tank. This model can be used to design chokes which allow for the dissipation of the energy released during pressure let down by spreading the stream over a significant portion of the slurry pool in the receiving tank to minimize wear on equipment near the nozzle exit and the bottom of the slurry tank. An example uses the model to choose the nozzle expansion (area) ratio to select the outlet slurry velocity and slurry expansion angle.

Jan 1, 2004

By Norman O. Lotter

The problem of quantifying the full performance potential of an ore body in a concentrator, and how to configure a flowsheet to achieve that potential, either for a new operation or an existing one, is a strategic challenge. Modern flowsheeting technology that has been developed over the last twenty years has provided a suitable platform to achieve this. The integrated use of geology, compositional and quantitative mineralogy, sampling models, quality controls, and mineral processing, including flotation testing, has evolved into what is now called process mineralogy. Two specific tools have been developed and validated as standard methods in this toollbox. These are statistical benchmark surveying and high-confidence flotation testing. Both of these have borrowed from the sampling theories of Pierre Gy and from geostatistics. Additionally, they work on a replicate measurement and averaging basis, thus reducing the overall random error level. With this arrangement, one is in a position to characterize the ore from true samples and identify and quantify the economic minerals present in a manner that easily brings out the processing implications and likely grades and recoveries. In particular, the approach captures the variation in the ore body, which, if properly translated into the flowsheet design, minimizes the risk that unexpected responses will develop in the concentrator operations. A further advantage is that successful plant trials are now possible and practical. An overview of this approach is presented with two case studies.

Jan 1, 2011

A Seismic Hazard Scale (SHS) has been developed to provide a practical seismic hazard assessment tool applicable to mine site personnel. It has been applied to seismic data sets from numerous Western Australian mines. The SHS is applicable when quantifying seismic hazard on a mine wide scale, on a mining block scale, and on a local cluster-by-cluster scale. Spatial mapping of variations in seismic hazard is a particularly powerful application of the scale. The SHS is sensitive to temporal increases in seismic hazard. It has also been shown that the SHS can be applied to estimate seismic hazard when seismic monitoring data are not available. The SHS is a simple derivation of the Gutenberg-Richter relation. There are assumptions and limitations to the SHS that need to be considered when applying it to mine seismicity data.

Jan 1, 2004

By Met M. E, Worner H. K

During the past two years, a large number of creep tests has been carried out on electrolytic lead, special assay lead and ordinary refined (Port Pirie) lead. Some of these tests have already been reported.1§ In addition, an attempt has been made to estimate the influence of the individual elements present in small traces in Port Pirie lead. The present paper gives the results obtained when small additions are made to "U" lead of the composition shown in Table 1.(which has been used throughout these investigations during the past few years). The additions were silver, antimony, bismuth and zinc. The results of the addition of tellurium have already been communicated. This investigation was intended to run parallel with a similar one using electrolytic lead as a basis and adding one element at a time.Actually, the experiments using "U" lead have got rather ahead of the others. The important point has emerged, however, that the effect of a .given addition may be appreciably influenced by the presence of traces of other elements.In most of these tests, an initial stress of 500lb. per sq. in. has been used. Whilst it is fully appreciated that this stress is higher than those used in practice, it has to be borne in mind that an improvement in creep resistance was *Manuscript received December 11th, 1936.

Jan 1, 1936

By Scott W. Hazen

This report presents the results of a statistical analysis of a limited amount of sample and assay data from a production panel in an open - pit phosphate mine in the Phosphoria formation in Idaho . A frequency distribution analysis is shown for the assays , sample interval lengths , and products of assay and sample interval length for the millshale , furnace - shale , and main phosphate beds . Correlation techniques were used to show the relationships between assays and sample interval lengths . Within- drill - hole and between - drill - hole correlation were also examined as a means of predicting grade trends in the ore . Simulation methods , utilizing a digital computer , were used to establish assay populations that could be used for estimating grade of ore , cutoff grades , and deposit or bed identification .

Jan 1, 1964

By H Li

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The central Nanling region in South China experienced multistage granite intrusive events and corresponding metallogenic processes during the Early Yanshanian period (190–140 Ma). In this study, a wide variety of published data on age determination, petrological characteristics, major and trace elements compositions, whole rock Sr–Nd contents and zircon Hf isotopic composition of the representative granite composites were systematically collected to estimate their cooling-uplift rates, granite evolution processes and mineral deposit formation. These granites have been classified into two groups based on their age and geochemical variations: Group 1 (180–165 Ma) and Group 2 (165–150 Ma). Major and trace element geochemistry suggests that Group 2 experienced more intense magmatic evolution and differentiation than Group 1. In addition, Group 1 granitoids are classified as A1-type alkaline rocks with faster cooling and uplift rates, whereas Group 2 granites are considered as A2-type aluminous rocks with slower cooling and ascent rates. Furthermore, the Group 1 granitoids have younger Nd and Hf two-stage model ages but higher eNd(t) and eHf(t) values, indicating influence from crust–mantle interaction. In contrast, the Group 2 granites show different values, suggesting stronger upper crustal contamination or assimilation. The slowly cooled and ascended Group 2 granites experienced much heavier crustal contamination (or assimilation) and crystal fractionation, contributing to the large W–Sn mineralisation in the central Nanling region. The Early Mesoproterozoic (1.6–1.4 Ga) crustal basement of the Cathaysia Block in South China is the ore source bed for the world-famous Nanling W–Sn polymetallic mineralisation.CITATION:Li, H, 2015. Where is the source of the world-famous Nanling W–Sn polymetallic mineralisation?, in Proceedings PACRIM 2015 Congress, pp 619–622 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By U. N. Bhrany, N. Arbiter

Over the last one hundred years the problem of assessing the efficiency of energy consumption in producing rock breakage has been studied by many investigators from a variety of viewpoints. Their contributions fall into three main categories: (1) those characterized by a priori assumptions of a relation between the energy required for fracture and the degree of fragmentation produced (e.g. Rittinged(l), Kick(2) Bond(3)); (2) those studying simple systems with controlled energy applications (Gross(4)?(5) ); (3) those treating operating data to develop practical relative measures of efficiency (Coghill(6), Taggart(7)). Closely involved in the efficiency problem is the characterization of size distributions produced by comminution. Unless an experimental size distribution can be approximated by a distribution function and its constants, it becomes difficult if not impossible to develop quantitative energy-particle size relationships. While many such functions have been proposed, none are both completely adequate and convenient. The simpler fonns usually describe only a part of the sizing data, while those which apply to a greater extent are cumbersome(8). The thesis underlying the study here reported can be stated as follows: Size reduction in a tumbling mill subjects ore particles to a relatively constant fracture-producing environment. The intensity of the forces is determined by such factors as the mass of the breaking bodies (rods, balls, rock), and the speed and dimensions of the shell. For a particular ore the extent of size reduction will depend both on the intensity and on the duration of exposure. The latter is the residence time in a batch mill, or is determined by the effective volume and the flow rate in a continuous mill. Size reduction can thus be regarded as a rate process in which the weight of material in size intervals varies as a function of grinding time. Although both the rates of disappearance of coarser sizes and

Jan 1, 1961

By E Bouchard March, F Lavoie, B Legare, K Bourassa

Quebec Iron Ore (QIO), a subsidiary of Champion Iron Limited (Champion), completed the restart of the Bloom Lake iron ore mine located in the heart of the Labrador Trough region of Northern Quebec, Canada in February 2018. Prior to its restart, the concentrator flow sheet underwent major upgrades which brought the iron recovery to the highest of all Labrador Trough operations. After two profitable years of production, QIO, supported by Soutex, started to look at technologies to improve its current performance and integrate into its expansion project flow sheet. From the lessons learned while optimising Phase 1, the addition of a scavenger-cleaner processing stage was identified as an improvement opportunity to increase recovery, produce a higher-grade product, and further improve the stability of concentrate quality. In 2019, the NI-43101 feasibility study for the Phase 2 expansion, aiming to double the production of high-grade iron ore concentrate, was published. Based on the metallurgical test work, the hydraulic classifier was selected to perform the scavenger-cleaning duty for its well-established performance and known behaviour at the cleaning step in the Phase 1 plant. To validate laboratory results, a pilot scavenger-cleaning hydraulic classifier was installed in Phase 1. Although the hydraulic classifier was selected for the feasibility study, metallurgical test work performed with the REFLUX® classifier showed interesting potential. It was thus decided to also install a pilot RC300 Reflux classifier at the scavenger-cleaning stage in Phase 1. Despite their apparent great similarities, the metallurgical performance was significantly different, and many dozens of sampling campaigns highlighted the different performance of both pieces of equipment considering the feed material particle size. This article presents the pilot plant results in terms of recovery, selectivity and stability for both the Reflux classifier and the hydraulic classifier operated in a scavenger-cleaner stage at the Bloom Lake iron ore concentrator.

Nov 8, 2021

By A. Brown

"The first printed report on Canada's coal resources was published in Paris in 1672(1. Written by Nicholas Denys, then Governor for France of Isle Royale (Cape Breton Island), the report dealt exclusively with the coal of the Atlantic region because little or nothing was known about the interior of North America. Clearly, also, he wrote about a resource of which much was known among the military and early settlers of that day. This early knowledge is not surprising because the presence of coal is clearly displayed in the coastal cliffs of Cape Breton as it was also, at a later date, to the first arrivals on Vancouver Island.An example of early use was that of the French garrison at Fort Louisburg in the first half of the 1700s. Still earlier, in 1643, Governor Winthrop of New England reported the receipt of a small ship load of coal from New Brunswick (2). Despite this early knowledge there was no significant development of coal mines until the 1800s. This had to await the ending of wars between the French and British factions and the growth of population. Basically, also, its development awaited the beginning of the Industrial Age. Organized coal mining began in Canada in 1825 with the formation of the General Mining Association. This British firm was the creation of a group of London jewellers which had been granted royal rights, by the British crown, to all minerals in Acadia (substantially the present Maritime Provinces). The Association took over a number of existing small mines and opened up larger operations in the Sydney coal field. Subsequently, it expanded to the mainland Nova Scotia fields at Stellarton and Springhill. The Association continued in existence as the major coal producer in Canada until 1899 when it sold its properties to the Nova Scotia Steel and Coal Company, Limited (3). This Montreal-based firm managed the coal mines as a major Canadian producer of coal until 1968 when financial problems led to the expropriation of the mines by the Government of Canada. The federal government established the Cape Breton Development Corporation to operate the larger mines on Cape Breton Island. This Crown corporation continues to be a .major producer of coal in Canada."

Jan 1, 1985

By Maurizio Siepi, Fabio Santillan, Lyndon Bedford, Carlo Crippa

"Abstract: Wolf Creek dam, on the Cumberland River in Kentucky, US, operated and maintained by the Nashville District of the USACE, is the Corps' largest reservoir east of the Mississippi river. The 1748 m (5,736 ft) long Wolf Creek dam combines earthfill and concrete gravity sections. Construction began in 1941 and was completed in 1950. The dam showed signs of instability in the 1960’s, and in the late 70’s an in-depth project of rehabilitation was undertaken, using both grouting and secant piles. The works saved the dam, but in the late 90’s further signs of distress worried the Nashville district of USACE which, after a study conducted on the water seepage, concluded that construction of a new concrete barrier cut-off wall was needed. In 2009, the $341.4 USD million contract was awarded to TREVIICOS-SOLETANCHE JV.The new wall, located upstream of the concrete monoliths, has a minimum thickness of 60 cm (24 in.), and runs the length of the embankment, into the right abutment, for about 4,200 feet. The founding depth reaches 84 m (275 feet), well below the zone of solutioning. With a total surface approaching 92,903 sq.m (1,000,000 sq.ft), the Wolf Creek barrier wall is unlike any other project in the world.The construction of the cut-off wall followed a complicated but logical sequence of several operations, involving a variety of technologies: grouting, hydromill, directional drilling, and secant piles with reverse circulation. The intensive rock grouting program was aimed to minimize the risk of slurry loss and extend the positive cut-off further deep. Subsequently, an Encasement Concrete wall was installed with hydromill, toeing into the rock, to protect the embankment during the following phases. Smart holes were then drilled into the Encasement wall down to the final depth. Eventually, the holes were used to install the secant piles by employing the reverse circulation piling method.An extensive verification campaign has confirmed the superior quality of the cutoff wall consisting of 1200 secant piles, exceeding by far USACE’s requirements. The main project was substantially completed in early 2013. A small portion of secant piles wall will be installed downstream of the dam, to close the switchyard, finishing the project in the early months of 2014.IntroductionWolf Creek Dam is located on the Cumberland River in south-central Kentucky. The Nashville District of USACE operates this multipurpose dam to provide hydropower, flood control, water supply, and water quality benefits for the Cumberland River system and surrounding region. Lake Cumberland, created by the dam, impounds 7,400 million cu.m (6 million acre foot) at its maximum pool elevation of 232 m (760 ft) above sea level. This lake is the largest reservoir east of the Mississippi and the ninth largest in the United States, and attracts 4.89 million visitors, more than Yellowstone National Park (2.87 million).This paper describes the recently completed works for the rehabilitation of the dam, accomplished by TreviICOS-Soletanche JV with the construction of a new Barrier Wall."

Jan 1, 2014

By S. H. Katz, J. J. Bloomfield

Fires in zinc dust have sometimes given particular trouble owing to their resistance to extinguishers and the liability of explosions . Similar problems , notably with aluminum dust* , have previously been subjects of investigation by the Bureau of Mines .

Mar 1, 1922

Myths and misconceptions regarding cyanide in the mining industry are common. This is not surprising, given the other uses to which cyanide is, and has been put. Unfortunately, the economic benefits, largely due to the introduction of cyanide in towns such as Waihi are often unrecognized. In the current "green" environment, the New Zealand mining industry faces constant scrutiny and challenge. The use of cyanide in hard rock mining is one area which can stir the emotions of the public.   Cyanide can be transported, stored, used and disposed of in a safe manner. The modem mining industry has an excellent record regarding the safety and environmental issues relating to cyanide. Many of the fears relating to cyanide in the mining industry have proven to be unfounded. It is important that this reputation is maintained. This is possible given proactive and ongoing management of cyanide issues.

Jan 1, 1997

The selection of the mining fleet can have as much of an effect on the efficiency and effectiveness of an operation as the mining method. This is not to say that inefficiencies are only attributable to inappropriate equipment selections, these aspects have many factors but are not the subject of this paper.This paper will give an overview of equipment selection processes that have been utilised to date. It will also look at the increase in application of study programs/simulations from an aspect of accuracy, as well as the importance of enabling the analysis of multiple sensitivity scenario planning. An aspect that is increasingly important in project planning with commodity market movements.Another aspect that is increasing in popularity is that of automation, what effect does this have on equipment selection? What additional aspects need to be taken into consideration when assessing Automation of equipment from the beginning of a project as well as introduction into an operating mine?Once the selection process has been finalised and equipment implemented, how do we, as an industry, 'close the loop' through analysis of estimated versus actual equipment application?

Dec 6, 2010

By J. S. Mason

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. Detailed paragenetic studies of the post-tectonic fracture-hosted vein mineralisation have demonstrated a complex paragenesis, reflecting a multi-phase combination of regional metallogenesis and tectonics through time. Previously published work regarding paragenesis and zoning was oversimplified. Two major epochs of mineralisation resulted in the emplacement of the A1 group of assemblages, from which lead, copper and silver were the main metals mined, and the A2 group, whose galena is only moderately argentiferous but which were major sources of lead and zinc. Tectonic and tentative isotopic evidence points to post-orogenic relaxation as the mechanism for development of the A1 assemblages in the early Devonian, whereas the A2 assemblages are believed to reflect Variscan extensional regimes and regional metallogenesis in the early Carboniferous and Permian

Jun 19, 1905

By Carlos G. Valenzuela

The value generally accepted for stacking-fault energy, of copper has been approximately 40 ergs per sq cm based on Fullman's2 value for the coherent twin-boundary energy and the assumption that is twice the twin boundary energy However, Thornton and coworkers8 determined that the lower limit of for copper is approximately 60 ergs per sq cm, based on measurements of dislocation-node radii. They suggested that the assumption of = 2t is invalid. It is the purpose of this note to present results which indicate that the values of obtained by measurement of twin-grain boundary intersections and the values obtained by measurement of dislocation-node radii are actually compatible. The most reliable values for of the a brasses, based on electron-microscope observation of dislocation nodes, are probably those values reported by Smallman and Green6 who applied the Siems correction (1961) to data obtained by Howie and Swann.3 These values shown in Fig. 1 give an extrapolated value of approximately 70 ergs per sq cm for pure copper. In the present work, Fullman's method for determining the stacking-fault energy of copper was extended to the a brasses. High-purity copper (99.999 pet) and high-purity zinc (99.999 pet) were mixed in proportioned amounts and melted in sealed and evacuated quartz tubes. The alloys were homogenized for a week at 750°C and chemically analyzed by means of X-ray fluorescence. These alloys, along with a specimen of pure copper, were rolled to 98 pet reduction and a thickness of 0.009 in., resealed, and annealed for 40 hr at 715°C. Values for the ratio of twin-boundary energy to the grain-boundary energy, it gb, were obtained from measurements of dihedral angles formed at the intersections of twin boundaries and grain boundaries by using Fullman's2 mechanical analogy of surface tensions acting at the intersection of an annealing twin and a grain boundary. The angles between the twin traces and the grain boundaries were measured for a large number of twin-grain boundary intersections at a magnification of X500 using a rotating mechanical stage on a Reichert metallograph. The rotary stage has a calibrated angle scale with vernier so that measurements can be made to 0.1 deg. The mean twin-grain boundary energy and standard deviation were calculated for copper and each of the brasses by the use of an IBM 7072 computer. It was found that the mean value of gb stabilized after approximately 100 twin-angle measurements. This was determined by plotting the mean against the number of angles measured. Since the measured angles deviate from true dihedral angles, a correction factor for grain orientation, discussed below, was applied. The stacking-fault energy was then calculated from these values and the values of grain-boundary energy derived by Taylor.7 The data obtained are tabulated in Table I. Values for stacking-fault energy are plotted in Fig. 1. The value of gb for the specimen of 1.03 pet Zn is close to the value obtained by Fullman2 for OFHC (99.98 pet) copper, 0.045. It is believed that the purity of the copper affects gb significantly. The 99.999 pet purity Cu used in this investigation yielded a value of yt/ygb, 0.76, which is much higher than that obtained by Fullman. Additional evidence suggesting that the purity of

Jan 1, 1965

By Scott O’Brien, Richard Williams, Camilo I. Mejias, Elias Godoy, Javier Sierra

High-rate thickeners play a critical role in tailings management by enhancing water recovery and increasing solids concentration. However, these units face operational instability due to fluctuations in feed solids, flow rate, and flocculant response typically managed in manual mode with delayed corrective actions. This work presents an adaptive automatic control algorithm designed for dynamic thickening environments. The algorithm integrates real-time measurements of feed density, rake torque, bed level, and turbidity (overflow), optimizing the underflow slurry density while minimizing suspended solids in the overflow. The proposed control strategy is modular, simple, scalable, and applicable to both existing and new thickening systems, offering a robust alternative to manual operation in increasingly demanding metallurgical environments.

Feb 22, 2026

By G. A. Sutton

This paper, describes a case example from San Manuel mine, where in situ copper leaching of the supergene zone was done over a 14 year period (1986–1999) in conjunction with underground and open-pit mining operations of a copper porphyry deposit. In 1993–1994, testing of well fields was done to determine the amount of copper that would be recovered from in situ leaching of the supergene zone, which was composed primarily of chrysocolla and copper-clay minerals. It was determined that the leach fluid would reach 70% (‘sweep efficiency’) of the copper minerals and that 75% of them would be leached for a recovery of 52% of the acid soluble copper. However, the final results from Zone 6, which had the longest leach history, showed that approximately 42% of the acid soluble copper was recovered, indicating that the `sweep efficiency’ was closer to 55%. Comparison of drill-core assay data from two holes, one drilled before (ARM158) and the other after (SMO9607) leaching, also indicate that approximately 42% of the acid soluble copper was recovered. The discrepancy between the predicted (52%) and actual (42%) recovery is probably related to a combination of factors, including difficulty in maintaining fluid saturation, channeling effects and gypsum precipitation. INTRODUCTION In situ copper leaching at the San Manuel mine, Arizona, was initiated in 1986. It was recognized that some of the copper oxide resource was not going to be economically recoverable by conventional open pit and heap leach methods using solvent extraction and electrowinning (SXEW). A high stripping ratio would be required to access part of the resource. At the time, in situ leaching was becoming popular in the uranium industry but the approach was virtually unknown in the copper industry, especially not at a large scale.

Jan 1, 2019

By M. M. Kim

As-electrogalvanized coatings of pure Zn, Zn-11% Fe, and Zn-18% Fe coatings were characterized in terms of initial crystal structure and surface morphology. Samples were then subjected to heat treatments simulating the paint bake cycle of automobile manufacturers. Surface morphology changes were correlated with the process variables, and crystallo.graphic changes were interpreted by mapping heat treatment routes on the Fe-Zn phase diagram. The morphology of pure zinc electrogalvanized coatings with heat treatment from platelets to smeared platelets. The zn-11% Fe coating changes with heat treatment from tetrahedral nodules to a mixture of round and tetrahedral nodules, with the Zn-:18% Fe coating always having round nodules. Regarding crystal structure, a critical transformation time can be defined at any selected temperature, below which the crystal structure does not change. This temperature is related to iron content.

Jan 1, 1990