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A quantitative chemical model of the rocks of the Broken Hill lode environment is presented to illustrate a stratiform orebody in a meaningful form to scientists interested in environmental control on the chemicalcomposition of sediments.Even though this study was restricted by the narrow range of rock analyses available it is obvious that significant chemical differences exist between the various rock units and also that some association of metallic sulphides with Ca, Mn, Fe, and P is indicated.Correlation of this evidence with that from other mining fields may point out more definite chemical relationships and elucidate the puzzle of the mode of formation of many stratiform orebodies.

Jan 1, 1968

By R. M. Cooper, H. K. Herbert, D. N. Phillips

A study was carried out to determine the effects of adding CaCO3, Fe, Al and CaSi2 to the ladle, rather than to the raw materials, in order to increase the concentration of Ca, Fe and Al in the final product to meet customer specifications at Simcoa's Kemerton plant in Western Australia. LA-ICP-MS, SEM-EDXRA and ICP-AES analysis of samples and controls showed that the technique is suitable for controlling minor element concentrations. Iron was successfully added, while calcium silicide with aluminium proved better than limestone with aluminium for controlling Ca and Al concentrations in the silicon

Jun 19, 1905

By Paul G. Marinos, Vassilis Marinos, Evert Hoek

The Geological Strength Index (GSI) is a system of rock mass characterization that has been developed in engineering rock mechanics to meet the need for reliable input data related to rock mass properties required as input for numerical analysis or closed-form solutions for designing tunnels, slopes, or foundations in rocks. The geological character of the rock material, together with the visual assessment of the mass it forms, is used as a direct input for the selection of parameters for predicting rock mass strength and deformability. This approach enables a rock mass to be considered as a mechanical continuum without losing the influence that geology has on its mechanical properties. It also provides a field method for characterizing difficult-to-describe rock masses. Recommendations on the use of GSI are given and, in addition, cases where the GSI is not applicable are discussed.

Jan 5, 2007

By J. D. Appleton, J. Ridgway, K. B. Greally

Paper presented at the 28th International Geological Congress held in Washington DC, July 1989 (International geochemical mapping sessions). The results suggest that meaningful geochemical maps can be produced from very low-density surveys, and that existing data sets could perhaps be incorporated into such a map series with the use of a system such as Uniras software. There are still many problems to be resolved, however, including the compatibility of data derived from different analytical methods, and the precise methods to be employed will necessarily require international agreement. Sampling densities should be chosen on the basis of the scale of the geochemical and geological features to be distinguished and will vary from region to region. Reanalysis of selected samples from archives to increase the range of elements determined or to unify analytical methods is only likely to be effective if the original survey was at quite a low density

Jul 1, 1991

By David Hopkins, Steve Klein, Bradford Townsend, Ed Sum, Derek Penrice

INTRODUCTION The Transbay-Caltrain Downtown Extension (DTX) Project involves the construction of an approximately 1.5-mile rail line that will extend Caltrain commuter service and the future California High Speed Rail system into downtown San Francisco. The underground rail extension will be constructed by mined tunnel and cut-and-cover methods. Tunneling challenges include difficult ground conditions, low rock cover, the presence of historic buildings along the alignment, and the large tunnel span, ranging from approximately 50 to 65 feet. Three mined tunnel construction methods were evaluated: the Stacked Drift Method, the New Austrian Tunneling Method/Sequential Excavation Method (NATM/SEM), and Tunnel Boring Machines (TBM). This paper describes the challenges presented within the mined tunnel section, and summarizes the evaluation of tunneling methods that led to the selection of NATM/SEM. PROJECT OVERVIEW The existing Transbay Terminal opened in downtown San Francisco in 1939. This facility is antiquated, and does not meet current building seismic safety standards or the transportation needs of the Bay Area. For these reasons, San Francisco voters approved Proposition H in 1999, which proposed to construct a new or rebuilt regional transit center at the site of the existing terminal and extend Caltrain commuter rail ser-vice to the new transit center. The new transit center is the hub of the Transbay Transit Center (TTC) Program, which will greatly enhance regional transit service by providing connectivity for six Bay Area transit providers at one facility. The program will be the largest inter-modal centerwest of New York City. The TTC Program is comprised of two major projects, the Transit

Jan 1, 2007

By Joanna LaForte

"In response to “Arctic Mineral Wealth —Equitable Participation with Aboriginal Landowners – A slow or fast process?”, this author’s impression is one that, to her, seems obvious — this is definitely going to be a slow process. To question this issue seems ridiculous, unless the mining industry is considering following the same patters of the past, thereby adding to the suppression and injustices to which the aboriginals are so accustomed. To make genuine progress, where trust and good communication has been achieved with time as a factor in proceeding, the author feels, without a doubt, that the triangle of industry, government and aboriginals will seriously have to be restructured or eliminated. Anytime you mix government with progress, along with other problems, you are looking at bureaucracy, and that takes time. Issues such as the settlement of land claims have not been resolved, and in all likelihood could take forty years to finalize. Aboriginals have been suppressed for centuries by governments and industries with ethnocentric ideologies, and now that they are in a position to reclaim their lands, attain their own economies and government, and truly secure a wealthy, self-sufficient legacy for their descendants, how can anyone imagine they’ll move quickly? This author also strongly disagrees to some sections of Mr. Wakefeld’s article and will expand on her objections.We question whether aboriginals under-stand the process of mine development. If we encounter an electrical problem in our home, o we not call an electrician without having to learn the trade ourselves? This comparison seems simplistic, but does convey a point. As cited, “there are now over 100 000 aboriginals who have completed post-secondary education.” Are the numbers revealed in Mr. Wakefeld’s paper there to scare us? Is he suggesting that without the industry’s haste, the aboriginal’s new found intelligence could pose a problem to the mineral explorer. While it is true that not all are highly educated, the aboriginals have specialists in market fluctuations, feasibility studies and the needed skills. They have specialists, such as their representative organization of COPE 1984, (the Committee for Original People’s Entitlement), who under-stand their cultures, language and desires. Their education should expedite the negotiations and end the power struggles equitably. Aboriginal people are not stupid. Once they have reason to be proud, regain their communities and know the direction that they’re headed, their self-determination will return."

Jan 1, 1996

By James R. Wickens, David La Rosa, Robert E. McIvor, Adrian Dance

"The comminution circuit at Barrick Cortez Gold Mine uses an open circuit primary jaw crusher followed by a standard SABC grinding circuit. The grinding circuit incorporates a 26’Ø x 11’ SAG mill, an Omnicone 1560 pebble crusher and a 16’Ø x 28½’ ball mill. Both mills are driven by 4500 HP motors.In 2007, several comminution circuit studies were performed to assess circuit performance and map a course for improvement. This paper discusses the results of those studies including an analysis of mine-to-mill opportunities, grinding work index efficiency, and ball mill functional performance. Subsequently, improvements to the circuit were made to enhance operating efficiency. Specifically, improvements to the pebble crusher liner configuration, advanced process control system (expert system) and ball mill classification and ball charge are discussed. In addition, other current and future improvement opportunities are discussed.INTRODUCTIONThe Barrick Cortez property is expanding to include the new Cortez Hills open pit and underground mines. Ore from these new mines will be processed in the existing Pipeline mill facility. In conjunction with ore characterization work, performance of the comminution circuit needed to be quantified. Thus, in 2007, the comminution circuit was surveyed and opportunities for improvement identified.Figure 1 below shows the Pipeline mill flowsheet. It is a standard SABC grinding circuit using an open circuit primary jaw crusher followed by a 26’Ø x 11’ (7.92m Ø x 3.35m) SAG mill, in closed circuit with a Omnicone 1,560 pebble crusher, and a 16’Ø x 28½’ (4.88m Ø x 8.69m) ball mill. Both mills are driven by 4,500 HP (3,357 kW) motors. The SAG discharge screen aperture is 5/16” (8 mm) x 1-1/16” (27 mm) slots. Ball mill circuit classification is done with Krebs D20B cyclones."

Jan 1, 2009

By Taylor R. G

This paper reports a biogeochemical study of the Siberia lode of the Herberton tin field. Soil near the orebody contained high levels of Fe, Cu, Pb, Sn, As, Mld Mn. Polycarpaea spirostylis and Indigofera dominii were associated with these high levels but several other species apparently could not tolerate them. The potential of these species as indicator plants is discussed.

Jan 1, 1975

Were it simply a matter of extracting tin from the simple tin sulphide, the proposition would undoubtedly be simple enough. When, however, other valuable metallic sulphides are combined with the tin, and it is required to separate these intomarketable products, then the proposition becomes somewhat complex, and such is the case with the class of material of which I am about to write. The locality where it occurs is Howell, New South Wales, and chiefly at the Conrad Silver-Lead Mine. The tin sulphide occurs chemically alloyed with copper, iron and other metals associated with galena, pyrites, mispickel, blende and silver sulphide in varying proportions, and generally in a gangue of highly crystallised quartz.Several varieties of tin sulphides occur, and from the following analyses of three minerals, these being specimens specially selected free from foreign matters, it will be seen that the chemical composition is somewhat complex.

Jan 1, 1902

By C. Cornejo, C. Schuffeneger, J. Rosas

"At the end of 2010 the AMSA Esperanza Concentrator started commissioning. Located in the Atacama Desert this project is the first of several large size concentrators developed recently to operate in Northern Chile. In addition to the new operations to be implemented in the short term, many existing installations are planning expansions. The use of large size equipment is one of the common characteristics of the new concentrators, but also new technologies are being considered and innovation is present in most cases. Sea water or desalinated water will be required to process large tonnages of sulphide copper ores as well as gold bearing ores, since process water supply from the Andes will no longer be available. The high cost of sea water or desalinated water supply and the high cost of energy are not a limitation as the current metal market scenario allows obtaining an attractive NPV even from installations designed to process relatively low grade ores. A review of the current concentrators being developed in Chile is presented, including a description of the main design issues related to technology and innovation. An analysis of the Chilean mining industry is also presented, detailing mine and plant capacities as well as expected final products.INTRODUCTION The mining sector in Chile has become a reference when analysing the large concentrator plants projected or currently in operation all over the world. At present and as a consequence of the high price of metal commodities, most South American countries have an active mining sector. Chile is known as a major producer of metals. First records of copper production exported to Spain are dated to the early XVII century. Since then Chile has produced over 13% of the total copper ever produced in the world. After 1990 Chilean mining and the associated cluster of activities has substantially grown to levels never reached before, especially in the production of copper, gold and other non-metallic minerals. This dramatic increase is the result of an economic policy based on delivering comparative advantages and incentives for the admission of foreign capital to offset the weak domestic investment in previous decades. Massive mining of its huge mineral resources has allowed Chile to be a world leader in the production of copper and other base metals and mineral products."

Jan 1, 2012

The variation of carbon monoxide and hydrogen utilization with the amount of the reductant in the blast furnace bosh gas was investigated for the No. 4 blast furnace at The Broken Hill Proprietary Co. Ltd.iron and steel works. Newcastle. The degree of CO utilization decreased with increasing CO in the bosh gas; the H., utilization increased with the H., content of the gas. Empirical relationships for CO and H., utilization are proposed.H2, is 3-6 times as effective a reductant as CO at present levels of CO (34-39 per cent) and H2 (6-10 per cent) in blast furnace bosh gas. H2, gas injection into the blast furnace is proposed as a means of lowering the coke consumption, and the economics of H2 injection are evaluated.

Jan 1, 1975

Underground mine designs typically try to avoid extraction beneath streams and rivers of any significant size, especially when the overburden rock thickness between the stream bed and the mine is thin. Potential issues with mining beneath streams include excessive groundwater inflow to the mine; weak ground (roof, floor, and pillar) conditions; horizontal stress effects; as well as stream loss and other potential adverse environmental effects. However, there are times when crossing beneath a stream or river is necessary to move into a new area of mineral reserve without creating additional mine access points from the ground surface. Often, stream crossings are completed without thorough assessment, potentially resulting in increased costs, decreased safety, and, in some cases, failure to advance the mine. Selection of the most favorable location(s) to cross the stream must account for numerous factors and the associated assessment often requires a multidisciplinary approach. Stream crossing investigations often require geological, hydrogeological, geotechnical, and geophysical expertise. Phases of stream crossing investigations include desktop evaluation of maps and aerial photography, stream bed observations, drilling, detailed rock core logging, downhole geophysical surveying, hydraulic conductivity testing (packer testing), geotechnical laboratory testing, assessment, and reporting. The deliverables from a stream crossing assessment typically include geological, geotechnical, and hydrogeological characterization of potential stream crossing locations; classification of favorable and unfavorable crossing locations; recommendations for entry design and pillar sizing; and recommendations for if, and how, to conduct pre-grouting activities. Examples of technical aspects of data collection and assessment are provided based on decades of industry experience conducting stream crossing assessments in various underground mining scenarios.

Jul 28, 2020

By M. K. Mohanty

Over the years, screen bowl centrifuges have been widely used for dewatering fine coal in coal preparation plants in the United States and elsewhere. Its popularity is attributed to its relatively low cost, its high capacity of providing low moisture content product and its relative ease of operation and maintenance. It is generally recognized in the engineering and scientific communities that screen bowl centrifuges provide some degree of particle size separation while dewatering fine coal in a common application. However, the extent of differential partitioning of coarse and fine particles achievable by a screen bowl centrifuge has not been systematically studied in the past. The present investigation was aimed at conducting a parametric study using a statistically designed experimental program to better understand and optimize the size classification performance of a screen bowl centrifuge. A continuously operating screen bowl centrifuge having a bowl diameter of 0.5 m was used for this study at the Illinois Coal Development Park. Three key operating parameters, i.e., feed flow rate, feed solid content and pool depth, were varied to conduct a total of 17 experiments using a three-level factorial test matrix. Some of the best size separation performances achieved in this study may be described as having an imperfection value of 0.13 at an effective separation size (d50c) of 38 µm and an imperfection value of 0.27 at an effective separation size (d50c) of 2.8 µm. Due to an effective separation of ultrafine high ash materials, the ash content of the screen bowl feed was reduced from 22.3% to a minimum of 8.84% with a combustible recovery of 84.1% and an ash rejection of 71.6%. A higher combustible recovery of 92.1% was achieved at a product ash content of 12.5% with a d50c of 2.8 µm and imperfection of 0.27.

Jan 1, 2008

By Pat C. Hautala, J. R. Hoskins

This is a new era for the minerals industry. Never before has there been more need for effective communication. So said Robert Anderson, chairman and chief executive officer of Hanna Mining Co. He was speaking to the American Mining Congress's Communication Workshop. The question is whether there is enough industry concern to meet the challenge. Anderson observed that increased workshop attendance, in continuing tough times, reflects the industry's concern for communication. But, why were students, faculty, engineers, supervisors, and managers not at the conference? Communication applies to every manager, Anderson said. But he was the only operating manager present. And only one company sent operating supervisors. The remaining conference participants were public relations personnel, generally with nonmining backgrounds. And the program dealt mostly with public relations issues. Role of Communication in the Minerals Industry. It is well known that the minerals industry faces economic, political, and social problems. Economic shifts and foreign competition have created an international minerals industry and an international marketplace. This, in turn, calls for worldwide communication. Other factors effecting communication are: • Governmental protectionism as well as regulatory reforms call for increased interaction with governing officials. • Changing social values have created environmental issues and anti-industry attitudes. This intensifies the need for improved public relations. • Traditional work values are shifting towards self-actualization and humanistic movements. The work force is better educated and more informed. Employees demand more satisfaction, equality, and job autonomy. • The mining industry's task of managing its human resources is complicated by layoffs, job uncertainties, and bleak outlooks concerning employee morale and motivation. Technology and Information for a New Era As noted, this is a new communications era, one propelled by technology and information. Technology has led to reduced demand for raw materials by developing substitutes. Copper demand, for example, will never fully recover. Copper cables are replaced by fiberoptics; copper transmission lines, with aluminum. Technology has shifted the US from traditional to high tech and service industries. The speed, frequency, and scope of information transmission have greatly increased. But the most significant characteristic of this information is not the pace of advancing technology. It is the dramatic increase in the importance and frequency of our personal transactions. Knowledge has replaced raw materials and capital as the strategic resource. Information has replaced energy as the transforming resource. And the game against nature has become an interpersonal game (D. Bell, Post-industrial society, Physics Today, '76). In Megatrends, John Naisbitt says that information will soon double every 20 months. So, professionals will become "information workers." And communication will be the life channel of the information age. Thomas Wolfe said you can't go home again. Hanna Anderson said we are, indeed, facing a new day. It will never again be "business as usual." We must move into the information age with the rest of society. We cannot trust that the world will continue to rely on our products. Nor can we place the responsibility and control for problems and solutions outside the minerals industry. Improved communication is not a panacea. But, Anderson said, it is critical to the minerals industry. What is Communication? The word communication is overused. It is applied to every aspect of our lives. Satirist Tom Lehrer got sick of hearing about the need to communicate. He said, "It seems to me that if someone is having all that trouble communicating, the very least he can do is shut up!" Obviously, we cannot follow that advice (though we might wish that some others would do so). Communication is always going on. It is inevitable. Yet we have many misconceptions about com-

Jan 1, 1985

By Daniel Ko, Ian Bell, Shahram Tafazoli, Bahram Sameti, Aylin Azmin

Image-based remote sensing of rock fragmentation in mining and quarry applications essentially treats each rock in the image as a data object in order to determine the rock size distribution. An obvious challenge after rock delineation in a 2D image is the scale of the delineated objects. Conventionally, either objects of known size are placed in the scene or parallel laser pointer are used, both making some assumptions, to calculate scaling factors. These assumptions are applied to the whole scene rather than sensing individual rock attributes.

Jan 1, 2015

In bump-prone coal mines, roof and rib support is subject to dynamic as well as static loading. Although less frequently encountered, the dynamic loading component can result in violent coal expulsions into openings seriously threatening the safety of workers. Dynamic support systems that have been increasingly implemented in many deep hard rock mines for dynamic failure containment have not yet found their adaptation to deep coal mines at desired levels. This paper examines the potential use of some of these dynamic support systems in deep coal mining, particularly in the western United States. Fundamental principles of dynamic loading are reviewed in the context of their application to dynamic failure mechanisms in coal mines. Potential benefits and applicability of the suitable hard rock dynamic support systems are discussed in relation to coal bump mitigation. The resulting insight provides a starting point for development of dynamic support elements for bump prone conditions in deep coal mines.

Jan 1, 2009

By John F. Gamble

Amphiboles are hydrated mineral silicates five of which occur in asbestiform habits as asbestos grunerite (amosite) asbestos, riebeckite (crocidolite) asbestos, anthophyllite asbestos, tremolite asbestos and actinolite asbestos] and non-asbestiform habits (grunerite, riebeckite, anthophyllite, tremolite and actinolite). The asbestiform varieties are characterized by long, thin fibers while non-asbestiform varieties such as cleavage fragments form short fibers with larger widths. The U.S. regulatory method for counting asbestos fibers (aspect ratio [>]3:1, length [>]5 µm) does not distinguish between asbestos and cleavage fragments. The method biases toward increased counts of non-asbestiform cleavage fragments compared to long, thin asbestos fibers. One consequence of this regulatory approach is that workers can be erroneously classified as exposed to concentrations of asbestos (asbestiform amphiboles) above the U.S. 0.1 f/mL exposure standard when in fact they are not exposed to asbestos at all but non-asbestiform amphibole cleavage fragments. Another consequence is that the known carcinogenic effects of asbestos may be falsely attributed to non-asbestiform amphibole cleavage fragments of the same mineral. The purpose of this review is to assess whether amphibole cleavage fragments pose the same risk of lung cancer and mesothelioma characteristic of amphibole asbestos fibers. We identified three groups of workers exposed to non-asbestiform amphiboles: two groups exposed to grunerite (Homestake gold miners and taconite miners) and one group exposed to industrial talc containing non-asbestiform tremolite and anthophyllite in St. Lawrence County, NY. In addition to assessing strength of association and exposure?response trends in the non-asbestiform amphibole cohorts, comparisons were also made with cohorts exposed to the asbestiform counterpart (positive control) and cohorts exposed to the mineral (e.g. talc) that does not contain amphiboles (negative controls). The cohorts exposed to non-asbestiform amphiboles had no excesses of lung cancer or mesothelioma. Similar results were observed in the negative control groups, in stark contrast to the excess risks of asbestos-related disease found in the asbestos cohorts. The only possible exception is the twofold increased risk of lung cancer where exposure was to industrial talc containing cleavage fragments of tremolite and anthophyllite. However, this risk is not considered attributable to the talc or amphibole cleavage fragments for several reasons. A similar increased risk of lung cancer was found in Vermont talc workers, studied in the same time period. Their exposure was to relatively pure talc. There was no relationship between lung cancer mortality and exposure measured as mg/m3 years and years worked. A case?control study reported that all the lung cancer cases were smokers (or former smokers) and attributed the excess to smoking. There were two mesothelioma cases among the NY State talc workers exposed to cleavage fragments of tremolite and anthophyllite, but talc is not a plausible cause because of too short latency and potential for previous asbestos exposure. The positive controls of tremolite asbestos and anthophyllite asbestos exposed workers showed excess risks of both lung cancer and mesothelioma and positive exposure? response trends. St. Lawrence, NY talc does not produce mesotheliomas in animals while amphibole asbestos does. In sum, the weight of evidence fully supports a conclusion that non-asbestiform amphiboles do not increase the risk of lung cancer or mesothelioma. ©2008 Published by Elsevier Inc. Keywords: Amphiboles; Cleavage fragments; Lung cancer; Mesothelioma; Asbestos; Non-asbestiform amphiboles; Grunerite; Talc

Jan 1, 2007

By Aquiles Vivar

Ante los problemas de sismicidad inducidos por el sistema de minado en la Compañía minera Milpo, se planteó una solución a través del sistema de monitoreo sísmico único, donde se da una distribución espacial de 20 censores entre uniaxiales y triaxiales distribuidos en 3 niveles de producción en el área de influencia de las actuales operaciones para así ubicar, cualificar y cuantificar el fenómeno a efectos de realizar los análisis interpretativos del caso. En ese sentido, el presente texto describe el sistema de monitoreo, cuyo software sísmico está diseñado para determinar nuevas estructuras formadas a partir de los eventos sísmicos pre existentes reactivadas por la sismicidad inducida, así como el desarrollo de planos de isocontornos que permiten la diferenciación entre zonas de altos y bajos esfuerzos.

Sep 9, 2007

The State of New South Wales is highly favoured in having vast deposits of coal adjacent to and within easy reach of the coastal Ports. Not only is the quality of the fuel generally superior to any found in the other States, but it is greater in extent than in any other part of the Continent. For interesting and reliable details of the history of the discovery of coal, the geology of the coal bearing strata, analysis of the various coals and other valuable data, the readers are referred to the book recently issued by the New South Wales Government, entitled The Mineral Resources of New South Wales, by Edward F. Pittman, A.R.S.M., etc., by the direction of the Hon. T. L. Fegan, Minister for Mines. The mining community is indebted to the Minister for having had published the most valuable condensed record of the mineral resources of the State extant.For the purposes of this paper we will only give such a general description of the coal fields as will make it intelligible in connection with the subject of the coal mining in the State of New South Wales.

Jan 1, 1904

By Jorge Navarrete

La Corporación Nacional del Cobre de Chile produce cobre y otros subproductos a través de sus yacimientos y líneas de producción como las pirometalúrgica, hidrometalúrgica y biohidrometalúrgica. En este sentido, el presente texto señala la implantación de un LIMS para la industria minera de cobre. LIMS es una abreviatura genérica para los software de Administración de Información de Laboratorio, cuyo objetivo es relacionar la Informática, Quimiometría y Calidad.De forma que cumpla con los objetivos de adquisición y gestión de la información de pesaje, muestreo y análisis químico producida por diferentes áreas, tanto internos como externos y unidades funcionales.

Jul 17, 2000