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By Francisco Camus

El proceso de exploración en las campañas mineras es la primera fase del negocio y constituye una de los principales herramientas para su supervivencia, desarrollo y valorización de la industria. En este sentido, el presente texto señala la experiencia de Codelco en la exploración en Chile y su aplicación en Perú. Así, el conocimiento obtenido por Codelco realizado en el norte y centro de Chile, ha generado la formulación de modelos de exploración predictiva durantes los últimos diez años. Dichos modelos incorporaron el conocimiento logrado en el nivel de cada yacimiento individual, los entornos distritales y las franjas metalogénicas donde estos ocurren. En consecuencia, esta experiencia obtenida por Codelco y el reconocimiento de la continuidad en Chile, se extiende en el Perú y se presenta como una oportunidad de interés para el desarrollo de programas de exploración a futuro.

Sep 13, 2001

By Ilpo O. Auranen

Background: Mines of today are moving ever increasing tonnages of rock. The new ore bodies tend be of lower grade and located deeper in the earth?s crust. The industry?s focus to overcome this ?deeper but poorer? ore problem has traditionally been to lower the costs by increasing the scale of mining. This has resulted in an ever increasing size of mining equipment like drills, loading shovels, dump trucks. The main focus has been in reducing the cost per ton of mining. This cost focus has often resulted in increased waste rock dilution and more ore losses. From costs to value: Waste rock dilution means waste rock in the concentrator feed. It?s value in open pit mining is equal to the value of ore it replaces. In underground mining, waste rock dilution?s value is equal to the value of ore it replaces added to the costs of mining it. It is commonly accepted that waste rock dilution in open pit mining ranges between 5 and 20% and in underground mining between 5 and 40 % . In a typical large open pit mine ore value is from 20 to 60 USD per ton and mining costs are 1 to 3 USD per ton. One percentage point reduction in waste rock dilution represents savings corresponding to about 20% of total mining operation costs. The difficulty of reducing waste rock dilution comes from the complicated nature of the ores. Accurate ore waste-border detection has not been possible due to excessive costs. Core drilling combined with geochemical lab analysis is the most accurate method for locating ore waste borders. However, it is also expensive and time consuming, which is why it is often combined with somewhat lower cost methods like sampling drill cuttings from blasting drill holes or from reverse circulation drills and analyzing them in a laboratory. The main drawback with these methods, in addition high costs, lies in the sampling accuracy and in the quality control of the whole process when a large number of samples have to be handled manually. In every mine it is possible to halve waste rock dilution by using new on-line analysis technology .

Oct 1, 2009

By Thomas M. Barczak

State-of-the-art longwall roof supports provide effective strata control, but failures of these support systems still occur. To identify failure mechanisms and the impact these failures have on the safety of the support system, the U.S. Bureau of Mines has been conducting research on shield mechanics in the Bureau's unique mine roof simulator, as well as field studies of in situ support loading and investigations of longwall failures, Three types of failures are discussed: (1) inadequate support capacity, (2) structural failure, and (3) instability. Hypothetical situations with proposed courses of action and case studies of actual longwall failures are described. This information is intended to assist the Mine Safety and Health Administration (MSEIA) and industry mining personnel in safety evaluations of longwall roof support systems.

Jan 1, 1989

By J. Douglas Causey

In 1984, at the request of Bureau of Land Management, the U.S. Bureau of Mines studied the 13,730-acre Burnt Lodge (MT-065-278) Wilderness Study Area (WSA) in order to evaluate the mineral resources. The WSA is located in Phillips and Valley Counties, MT, about 55 miles south of Malta adjoining the Charles M. Russell National Wildlife Refuge. It is underlain by near horizontal sedimentary beds of the Hell Creek Formation, Fox Hills Sandstone, and Bearpaw Shale. No mines or prospects were found in the WSA. Bentonitic beds were examined, but are generally less than 1 ft thick and, except where exposed, are deeply buried. Kaolin-bearing sandstone in the Colgate Member of the Foxhills Sandstone was sampled and may have potential for use in structural clay products. However, remoteness and inaccessibility of the area make it unlikely that the material could be economically extracted even though some of the material is marginally useful.

Jan 1, 1985

By C. Fleming, J. R. Goode

ABSTRACT: Data were produced from two uranium project studies that were conducted in 2008, both involving uranium recovery from leached slurry by resin-in-pulp (RIP) with strong base resins. In both studies, excellent metallurgical results were produced. The loaded resins were eluted with strong sulphuric acid and recycled through RIP circuits in an integrated process. Resin losses by either abrasion or mechanical breakage were immeasurably low. Metallurgical results from these two campaigns are presented, along with a case study economic analysis of RIP versus the alternative processes of counter-current-decantation or filtration and solvent extraction.

Jan 1, 2011

By Lyne Côté, Jose Adante

"The Caribou underground mine, 50 km west of Bathurst, the Restigouche open-pit mine, another 30 km west and the concentrator located at the Caribou mine site resumed operations in July 2007 after a nine year shutdown. The Caribou operations achieved commercial production on Jan 1. By June, 2008, all metallurgical targets had been achieved or surpassed with the production of lead and zinc concentrates assaying approximately 50% Zn and 45% Pb respectively with recoveries exceeding 80% for Zn and 70% for Pb.The deposit features very fine-grained massive sulphide mineralization, which in the past has proven difficult to process. ISA Mill Ultra Fine Grinding Technology in combination with conventional flotation technology is used to process these complex oresSeveral modifications arising from experience gained from past operations, an extensive research project at Lakefield Research and post startup flow sheet and reagent alterations have been employed to achieve this break through performanceThis paper describes the design, start up and optimization of the Caribou operations including the many challenges faced including the flotation of mineral particles with K80s ranging from 35µm to 8µm.HISTORICAL BACKGROUNDThe Caribou massive sulphide deposit was discovered by Anaconda geologist Cam Cheriton in 1959. Anaconda initiated an extensive underground exploration and discovered a super gene copper blanket which was developed into a small open-pit mine-mill operation that ran from 1970 until the depletion of the copper ore in 1974. East West Minerals, an Australian public company, purchased the mine in 1986 and operated for only seven months producing a single bulk lead-zinc concentrate. In 1995, Breakwater acquired the Restigouche Open pit and Caribou underground deposits. Breakwater began milling operations in July 1997 but Caribou Mine failed to commercialize production, and the company decided to shut it down in August 1998, because of declining metal prices. The mill was plagued by mechanical and design problems, but deficiencies in metal recoveries prevented the operation from reaching desired levels."

Jan 1, 2009

Peñasquito is Mexico's largest gold producer, consisting of two open pits - Peñasco and Chile Colorado - containing gold, silver, lead and zinc. Over the next three years, mining activities in the pit are expected to be focused on lower grade ore in the upper parts of the Peñasco pit while stripping is emphasized to ensure an economically optimal pit shell design to maximize the net asset value of the operation. By 2019, Peñasquito’s gold production is expected to benefit from an improvement in mined grades as it recommences mining higher grades at the bottom of the Peñasco pit and significantly enhanced metallurgical recoveries with the planned completion of the Pyrite Leach Project ("PLP").

Jan 1, 2017

By Y. Héroux, A. Chagnon, M. M. Savard

"Résumé - Le gite de Pb-Zn de Gays River s'accompagne d'anomalies des propriétés de la matière organique (MO) et des assemblages de minéraux d'argile (AMA). L'association entre la minéralisation, la distribution de la réflectance de la MO et des AMA suggère que ces traceurs peuvent servir à I ‘exploration des sulfures de métaux de base dans cette région.A I ‘emplacement du gîte, la réflectance varie considérablement (0,8% à 1,88%), pouvant même afficher une baisse avec I ‘enfouissement, ce qui est interprète comme une altération chimique de la MO. Les valeurs les plus élevées s'accompagnent localement de quelques textures en mosaïque et délimitent une anomalie thermique au centre sud de la région. Parmi les minéraux des argiles identifies, I ‘illite et la chlorite sont terrigènes alors que la smectite, la kaolinite et la corrensite sont authigènes et, à l' instar de I ‘altération de la MO, résultent des nouveaux équilibres chimiques créés suite à la précipitation des sulfures.Abstract - The Gays River Pb-Zn ore deposit is associated with anomalies defmed from the characters of the organic matter (OM) and from the clay minerals assemblages. The relationships between these anomalies and the mineralization at the mine suggest that these parameters can be used as new guides for the exploration for base-metal sulfides in this area.The vitrinite reflectance (RJ shows a wide range of values (0.8% to 1.88%) and exhibits an anomalous suppressive effect with depth of burial at the mine site, suggesting a chemical alteration of the OM. The highest R"" values are associated with mosaic textures and outline a therrnal anomaly at the south-center of the studied area. Among the identified clay minerals, illite and chlorite are terrigenous, whereas smectite, kaolinite and corrensite are authigenous and, like the alteration of the OM, are due to the new chemical equilibria resulting from the precipitation of the sulfides."

Jan 1, 1994

By Max J. Spendlove

The Federal Bureau of Mines has been a leader in resource recovery research since it was founded in 1910. Until the early 19601s, most of the projects were concerned primarily with the task of extending and improving conventional technology oriented to secondary metals and minerals upgrading and processing for marketable products of highest value. By the mid-1960's with the passage of the Solid Waste Disposal Act of 1965, all resource recovery research programs were increased in scope and intensity as an effort to solve the growing number of environmental problems and the rapid depletion of domestic energy and mineral resources. Many new materials were investigated including urban refuse, manufacturing, industrial wastes, and stockyard wastes. The objective was to promote maximum recycling as the most practical answer to problems of waste disposal, pollution control, and the short supply of minerals and energy. The new research projects ranged from the conversion of animal manure and other organics to oil, to the recovery of precious and common metals from demolished aircraft and electronic scrap. This profile includes brief descriptions of many selected research projects that typify, the total spectrum of Bureau of Mines research in the important field of resource recovery.

Jan 1, 1977

By Brian Khalighi, Massimo Franceschi, Giovanni Giacomin, Gianni Porta

Headrace Tunnels and parts of the Access Adit Tunnels of Kárahnjúkar Hydropower project, KAR-14, in Iceland will be excavated using three full-face Robbins Tunnel Boring Machines (TBM). TBM sizes range from 7.23 to 7.63 meters in diameter and the total headrace tunnel length is approximately 40 km. The crushed rock is transported on conveyor belts to disposal areas near each Adit. The estimated average excavation rate is approximately 25 meters per day per machine. Electricity will begin to flow in April 2007, and the project is scheduled for completion in 2009. This paper is divided into four sections. In the PROJECT OVERVIEW section, a short overview of the scope of the project is presented. In the GEOLOGY section, the geological condition along the tunnel drives is briefly introduced. The TBM DESIGN section discusses the various design criteria and the resulting machine specifications. The paper concludes in the TBM OPERATION section with a case history describing the tunneling operation from start-up to the time of the writing of this paper.

Jan 1, 2005

By T. Gammatikopoulos, C. Gibson, M. Aghamirian

Lithium is an alkali metal found in brine deposits in the United States, Chile and Argentina, as well as in hard rock deposits in Australia and North America. In hard rock deposits, spodumene (LiAl(Si2O6)) is the major economic lithium bearing mineral. Spodumene is typically upgraded through a combination of dense media separation, flotation and magnetic separation. One of the major spodumene concentrate quality specifications is the iron oxide content because it will help determine if the concentrate is considered ceramic grade for use in ceramics and glass or chemical grade for use in lithium ion batteries. The rejection of iron bearing silicate minerals from artificial ore composites (high amphibole and low amphibole, high quartz/feldspar) from a hard-rock spodumene deposit was investigated using magnetic separation and flotation. The efficacy of Wet High Intensity Magnetic Separation (WHIMS) in iron rejection was found to be dependent on the mineralogy of the iron-bearing silicate minerals including modal distribution, liberation and association. When magnetic separation was conducted prior to flotation, the Fe2O3 grade in the final flotation spodumene concentrate was reduced from ~3% to ~1% Fe2O3 , and improved lithium recovery in flotation was observed. It was determined that it was most effective to conduct WHIMS on the flotation feed after scrubbing and de-sliming because this reduced the required magnetic field to recover iron-bearing minerals, likely because slime coating was greatly reduced. Flotation collector screening of four different collectors with varying rosin acid content demonstrated a potential increase in selective flotation of spodumene over some iron silicate minerals with decreasing rosin acid content in the fatty acid collector. However, due to marginal difference in flotation results with the various collectors tested, further testing is required to confirm the observations made and establish a hypothesis regarding the effect of rosin acid content.

Jan 1, 2017

By Sam S. Taylor

"INTRODUCTION This report deals with a comparatively simple application of some of the engineering principles involved in the evaluation, installation, and operation of air- or gas-injection projects and well-clean-out and repair methods to increase the producing rates of oil wells in partly depleted pools during the war. The methods suggested for developing gas-injection projects take into consideration that in general no new wells will be drilled because of wartime restrictions of equipment and manpower and that only existing wells and second-hand machinery will be used. Because air will be employed as the injection medium in secondary-recovery operations where natural gas is scarce and expensive, the disadvantages and hazards accompanying, its use are discussed. Engineering techniques recognized as best modern practice are discussed in relation to the effect of simple air-injection development of properties on postwar operations and Probable ultimate recovery of oil. The report is an introduction to where, when, why, and how an air-injection project should be installed and operated; it is not intended to be an engineering manual for technical guidance in the selection, development, and operation of simulative methods of oil recovery.The report is intended mainly for these thousands of operators in the Appalachian region owning a few wells prodding small quantities or oil daily. Many such operators are anxious to increase their production rates by simulative means and to rehabilitate their wells so that they will produce more oil to help win the war but, in general, are unfamiliar with secondary-recovery operations and cannot afford to hire technical assistance."

Sep 1, 1944

By John Sleavin

As part of the Link Light Rail project in Seattle, WA, work was completed at the Pine Street Stub Tunnel (PSST) in early 2007 for the Central Link project. This tunnel was excavated using cut-and-cover construction within the limits of Pine Street. The stub tunnel provides a turn back via double crossover for light rail trains running in the Downtown Transit Tunnel (DTT), as well as a connection point for the next phase of the project, the University Link (Fig. 1). Designing the new University Link tunnel connection to the existing PSST was a tricky task. The on-site geotechnical conditions, buried obstructions, geometry, requirements for construction and balancing operational considerations and neighborhood stakeholder concerns associated with the recently completed PSST combined to create a uniquely challenging assignment.

Jan 1, 2010

By C Verdel, M Lee, A Oorloff, K Welsh

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Thomson Orogen is a large but poorly understood element of Queensland geology. Extensive cover conceals the Thomson Orogen at depth, thus limiting studies to a small number of surface exposures. Previous studies of the northern Thomson Orogen have been restricted to the largest of these exposures in the Anakie Inlier and Charters Towers Province. Less extensive exposures, including Mt McLaren in east-central Queensland, are largely overlooked and poorly documented. Fieldwork suggests that Mt McLaren is a west-tilted fault block of Thomson Orogen metasediments that are at least 2200 m thick. The substantial thickness of these sediments (which we have named the Mt McLaren Formation) and the consistent shallow marine facies throughout the block suggest deposition in an actively subsiding basin. Initial dating of detrital zircons places deposition of the Mt McLaren Formation in the Late Cambrian to Early Ordovician, allowing correlations with formations of similar composition and age in the nearby Anakie Inlier and Charters Towers Province. Both of these areas have a long history of mining and exploration for gold and base metals, suggesting that correlation of basement sequences across these areas could be beneficial for exploration models of the Thomson Orogen as well as for tectonic models of eastern Australia.CITATION:Lee, M, Verdel, C, Welsh, K and Oorloff, A, 2015. Stratigraphy of the Thomson Orogen – new insights from Mount McLaren, north-east Australia , in Proceedings PACRIM 2015 Congress, pp 551–556 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By E. C. Baker

Costs of disposing of steel slag are estimated based on the present method and a proposed alternate method for a steel mill in the Pittsburgh area. Estimated cost data were calculated by the Bureau of Mines and do not reflect the investment and operating costs and credits of a specific steel mill and processing plant. The alternate method of steel slag disposal would result in an appreciable cost savings to the mill and concurrently supply the industrial and commercial markets with low-cost, high-quality construction materials.

Jan 1, 1970

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.Low-sulfidation epithermal gold mineralisation at Ridge Mountain occurs within the Oligocene to Miocene volcanic rocks comprising andesite, porphyritic dacite and diatreme breccia. A diatreme breccia complex with a NE–SW elongated orientation covers an area of 3.0 × 1.7 km. Four main stages of mineralisation were identified, comprising: E–W- to NW–SE-trending quartz-chalcedony veins with disseminated pyrite, chalcopyrite and gold. N–S- to NNE–SSW-trending breccia veins with quartz matrix and disseminated pyrite and accessory sphalerite, galena, chalcopyrite and gold. NE–SW-trending quartz and calcite veins with disseminated pyrite and accessory sphalerite, galena, chalcopyrite and gold. ESE–WNW- to ENE–WSW-trending quartz veins with disseminated pyrite. This stage is only mineralisation that is hosted by diatreme breccia and clearly postdates.Quartz veins of the first, third and fourth stage are less than 2 m wide. Only breccia veins of the second stage are up to 10 m wide. Gold is present in all stages as microscopic inclusions in quartz and sporadically in pyrite. Macroscopic gold can be seen in the first and second mineralisation stages. Gold commonly occurs in association with sphalerite, galena and chalcopyrite in the second and third mineralisation stages.CITATION:Kucera, J, 2015. Diatreme breccia-hosted epithermal gold deposit at Ridge Mountain, eastern Mindanao, Philippines, in Proceedings PACRIM 2015 Congress, pp 587–592 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By D Connelly

There is now a new generation of mobile crushing and screening plant systems available which have been developed based on the motivation of reducing truck haulage. Newly designed mobile crushing and screening plant systems have the advantages of mobility, flexibility, economy and reliable performance, making this system very appealing for small- to medium-sized projects or projects where a number of resources are separated by distance.A brief review of the past history and experience with transportable crushing plants provides an insight into some of the issues with transportable plants in mineral processing. A closer look at a simple model based on exploiting small but high-grade orebodies suggests the concept has merit, however there are many more engineering, logistics, legal, technical and management aspects which have limited the application of such a concept in the resource sector. This paper explores the concept in detail and endeavours to analyse the preferred commodities and scenarios under which the concept could be used and the economic and logistical limitations for iron ore. The paper also looks at the risk assessment criteria to be applied in selecting the type of resource projects where the model could be applied successfully. Other aspects considered in this paper are the project planning requirements, technical and economic feasibility, bankability and operability. Reference is made to the operating experience of contractors at a number of sites and feedback from the resource companies as managers of the projects.CITATION:Connelly, D, 2013. Mobile crushing and screening plant applications for small- to medium-sized iron ore projects, in Proceedings Iron Ore 20 13, pp 349-354 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By K. -C. Han, S. -Y. Kim

This study was carried out in a bid to survey Ganboke gold mine in Pala, Mayo-Kebbi Province, southwestern Chad. The Ganboke mine is now being prepared for investigation and development, and the research sought to perform rock properties tests of relevant rocks through its geological survey, rock mass evaluation, and in-situ and laboratory tests and analyze the stability by the means of limit equilibrium method, thereby suggest appropriate methods to design the pit slope and individual benches in Ganboke mine. Targenting GS1-GS1' section with the depth of 180 m and GS2-GS2' section with the depth of 150 m in the survey area, we set the height of the bench at 10 m and 15 m, and the angle of bench at 60o and 70o, respectively, and then reviewed the stability for dried condition and saturated condition. The result of examination indicated that it would be appropriate to set the bench height at 10m and the bench angle at 60o in developing the mine slopes concerned. Cette étude est réalisé dans le but de faire des recherches sur Ganboke mine d'or dans Pala, Mayo-Kebbi Provence, Tchad sud-ouest. La Ganboke mine est actuellement en train de étre disposé à la investigation et le développement, et la recherche a cherché à accomplir les tests de la propriétè des roches par l'intermédiaire de la étude géologique, la évaluation de la masse rocheuse, et in-situ et les tests de laboratoire et à faire l'analyse de la stabilité au moyen de la méthode d'équilibre limite, de ce fait à proposer le methodes propres à faire le plan de la pente et les gradins individuels dans la Ganboke mine. Concernant la section de GS1-GS1' avec la profondeur de 180 m et la section de GS2-GS2' avec la profondeur de 150 m dans l'aire d'étude, nous mîmes l'hauteur du gradin à 10 m et 15 m, et l'angle du gradin à 60o and 70o, respectivement, et alors nous avon reconsidéré la stabilité pour la condition sèche et la condition saturé. Le résultat d'examen a indiqué que il pourrait être propre de mettre l'hauteur du gradin à 10m et l'angle du gradin à 60o en développant les pentes de la mine concerné. Diese Forschung wurde um das Gold Bergwerk zu überschauen in Pala, Mayo-Kebbi Provinz, der Südwesten Chad ausgeführen. Das Ganboke Bergwerk ist jetzt zur Erforschung und Entwicklung vorgebereiten worden, und die Forschung suchte zu ausführen die Prüfungen der Felseigenschaft durch geologischen Überblick, Felsmassewertbestimmung, und In-situ und Lavorversuch auf, und analysieren die Stabilität mittelst der Grenzegleichgewichtsmethode, da-durch schlug die angemes-sen Methoden zu entwerfen die Böschungen und die einzelnen Bänke im Ganboke Bergwerk vor. Für den Abschnitt GS1-GS1' mit der Tiefe von 180 m und GS2-GS2' mit der Tiefe von 150 m in der Überblickfläche, wir setzten die Bankhöhe an 10 m und 15 m, und das Bankwinkel an 60o und 70o, beziehungsweise, und dann zurückblickten die Stabilität für die getrockneten Bedingungen und die gesättigten Bedingungen. Das Ergebnis der Untersuchung anzeigte daß es würde angemessen sein zu setzen die Bqnkhöhe an 10m und das Bankwinkel an 60o in der Entwickelungen vom Bergwerk be-teiligt.

Jan 1, 2003

By Steve Chorley

Open-type, or main beam, tunnel boring machines (TBMs) can achieve impressive rates of production. This type of TBM typically outperforms other types of TBMs currently in use around the world. In good ground conditions, main beam machines have achieved production rates of more than 1 km/month (0.6 miles/month). However, installing effective ground support in poorer rock conditions on main beam machines can be a major cause of concern. The design of main beam machines is such that installation of ground support equipment, particularly at the front of the machine in what is commonly known as the L1 support zone, has traditionally been limited to rock drills and basic working platforms. Personnel working in the L1 zone have, until recently, been protected by roof supports and extended fingers, often with restricted access to working areas.

Jan 1, 2011

By John Paul Gries

This Bureau of Mines report reviews the mineral industry of the Black Hills area, including Butte, Custer, Fall River, Lawrence, Meade, and Penning- ton Counties, S. Dak.; and Crook, Niobrara, and Weston Counties, Wyo. It includes discussion of geological occurrence, processing, and potential of 27 commodities that have been produced from the nine-county area. The value of mineral production exceeds $70 million annually. Gold and petroleum account for two-thirds of the total, followed by clays, cement, sand and gravel, and rock. The combined mineral industries annually consume 268 million kilowatts of electrical energy, 933 million Mcf of gas, and 2 million barrels of fuel oil. Water consumption is about 10,000 gallons per minute. About 2,700 persons are employed on a year-round or significant part-time basis.

Jan 1, 1974