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By Andreza Aparecida de Miranda

No mercado atual a organização que possui certificação ISO tem ganhos significativos de competitividade e credibilidade. A Companhia Siderúrgica Nacional é uma empresa que possui tanto a certificação ISO 14001 quanto ISO 9001 e TS16949. Para a manutenção dessas certificações é necessário que exista uma gestão sobre a aplicabilidade dessas normas e uma exigência legal é a qualificação dos seus fornecedores críticos para o Meio Ambiente e para Qualidade. O objetivo deste trabalho consiste em apresentar o modelo de monitoramento destes fornecedores nos quesitos performance de Entrega, performance de Qualidade e arquivamento das documentações legais. A Diretoria de Suprimentos atua de forma corporativa em 12 sites, e semestralmente gera relatórios para realizar este monitoramento e essa documentação gerada era arquivada em diversas pastas (em papel) em um único site, o que dificultava a consulta de funcionários que estivessem em outro site nos momentos de auditoria. 0 novo modelo contempla a ferramenta utilizando o próprio ERP, SAP/R3 que possibilita a consulta da documentação necessária, do fomecedor que desejar, de qualquer site, a qualquer momento. Essa ferramenta tem como objetivo agilizar a chegada de informação para quem precisar, em tempo real.

Jul 29, 2018

By D Bush, F Goddard

The electrification of Australian mine sites will see a boom in the use of batteries of all chemistries. Lead acid batteries, a traditional mainstay of the mining industry, are expected to nearly double by 2030, however their use will be eclipsed by the explosive growth in lithium batteries. By 2030 the lithium battery market is forecast to be nearly four times the size of the lead acid battery market. Unfortunately, this will result in a corresponding avalanche of waste batteries to be disposed of. Barely a day goes by without battery generated fires being reported in the media and they have become an increasing nightmare for waste management companies and waste facilities. The safe recycling of batteries will also become increasingly important for mine sites to achieve their sustainability goals and reduce their environmental footprint. What are the risks posed by waste batteries, what are the regulatory requirements and how can you manage or eliminate these risks? What current practises does your mine site currently have for the safe management and disposal of batteries from your site? How prepared are you for the coming avalanche of waste batteries?

Apr 16, 2024

By S. Nagamatsu

Alumina supported gold catalyst prepared by spray reaction method (spr) provides gold particle with about 20 nm of diameter. The gold particle size is larger than conventional gold catalysts. However, the spr catalyst shows higher catalytic activity for NO-CO reaction. In the present paper, we have discussed the local structures of spr-Au/Al2O3 catalyst by using Au L3-edge XANES spectra. In order to investigate the local structures of Au-sites, multiple scattering approach to XANES analysis was applied. Calculated Au L3-edge XANES spectra for fcc-Au and Au2O3 were in good agreement with the observed spectra. XANES spectra for spr-Au/Al2O3 were characterized by 4 types of Au sites (bulk, interface, surface and peripheral). In this case, almost all gold sites (> 90 %) are bulk site. The other sites are less than 10 % of gold particle. However, the experimental and the calculated results of Au L3-edge XANES spectra for spr-Au/Al2O3 require about 30 % of gold oxide or hydroxide. Bulk of Al2O3 contains a certain number of gold nano-particles, which was incorporated in the bulk Al2O3 support. In the interface area, gold oxide forms a few layers. This result was also supported by DV-Xa electronic structure calculations. The comparison of the catalytic activities of the spray catalysts and the impregnation catalyst for the NO-CO reactions imply synergy effects between gold nano-particles and alumina support.

Oct 1, 2003

By Mauricio Coto

Three bidirectional static load tests (BDSLT) were executed on bored concrete piles, as part of the permanent foundations for two buildings sites located at the Sabana, San Jose, Costa Rica, separated at a relatively short distance of about 1 km. Unit skin friction values obtained for both sites, principally for the “Lahar” layer show that in general, friction pile capacity from the tests is higher than anticipated per static calculations from soil borings geotechnical parameters correlations. Results from the tests were also compared with dynamic load tests (DLT) executed at other two sites in the surrounding area, and with a Finite Element (FE) Analysis that model soil-pile interaction for one of the projects. On the other side, some construction issues were detected on one of the sites, which negatively affected the end bearing capacity, but being that pile friction was higher than anticipated, the required overall pile capacity was accomplished. The BDSLTs results of these tests help to better understand the geotechnical behavior of the soil layers in the Sabana. Moreover, they also show that is possible to optimize the design and construction of other bored pile supported buildings and structures on the zone.

By Blake M. Paterson

The increasing global demand and lower price of gold has resulted in more advanced gold extraction techniques. One trend is the use of oxygen in place of air in the leaching process, which is proven to significantly enhance recovery of gold ore refractory in such techniques as CIP and CIL. This has resulted in a search for more reliable and cost efficient paradigms of oxygen supply. Many gold mines already realize the heightened recovery rate achieved with oxygen. Previously this benefit had only been available to the largest consumers of oxygen, near oxygen production facilities. Requirements of (1) to (20) metric tons per day have traditionally been supplied with expensive, delivered, liquid oxygen. Since many mines are located in remote areas, it is difficult to secure cost effective and continuous supply of liquid oxygen. However, the benefits of On-Site Oxygen Production combined with a self-generated bulk reserve supply are now available to mine sites. This paper explains and discusses the use of on site Pressure Swing Adsorption (PSA) oxygen production, coupled with a cryogenerator to liquefy oxygen for storage. This package offers continuous oxygen supply to mining sites in even the most remote corners of the world.

Jan 1, 1997

By Kenneth L. Schellie

In preplanning the reclamation of a pit or quarry the geology of the site is the name of the game! The planner must know the parameters of the deposit, the quantity and kind of earth materials to be removed, and the amount and nature of the materials to be left behind or wasted as the result of processing the marketable product. With many states and most local jurisdictions requiring reclamation plans prior to the issuance of mining permits, the need for accurate and complete data concerning the geology of the site becomes increasingly important. The producer need only know that marketable materials are available in sufficient quantity to make the mining operation economically feasible-the planner, in order that the land may be reshaped for a useful purpose, must have reasonably precise information as to the dimensions and configurations of the pit or quarry following extraction and the amount and type of materials available on the site (or in some cases offsite as well). Therefore the geology of the site is of major significance in determining the land forms and use capabilities of the property upon completion of the mining process.

Jan 1, 1974

By A. Chamaret

Minerals extraction is related to complex sustainable development issues that are subject to international and local controversies. Debates must be based on objective and comparative elements. Defining strong indicators for assessing impacts and performances of mining sites thus appears necessary to inform and support the decision-making process for stakeholders. Recently, many indicator sets have been developed on an international level based on top-down approaches, but they commonly lack legitimacy for stakeholders and adequacy to specific site issues. They thus need to be complemented by the consultation of local actors concerned by such mining activity, in order to define indicators that are closer to the needs and contexts of the specific sites. The question raised by this kind of top-down/bottom-up approach is how to organize and reveal the plurality of values and concerns associated with mining. Based on the principle of representative diversity, the approach undertaken at the Arlit uranium mines in Niger aimed at defining indicators that are understood and accepted by all actors. The aim was to measure the impacts and performances of mining sites in the four sustainable development dimensions, and at local, regional and national scales.

Jan 1, 2007

Validate the premise that there is measurable seismic activity associated with abandoned mint lands and that this activity can be used to determine stability of the abandoned mine openings, failure cycle of these openings, and susceptibility of the area to surface subsidence. Approach The U.S. Bureau of Mines conducted field investigations at two geologically contrasting sites, Colorado Springs, CO, and the Allegheny Portage Railroad Historical Site near Cresson, PA, to demonstrate that developing monitoring technology can be applied to any site. An array of seven geophones (velocity-measuring sensors) were strategically located to encompass an area at each site where failure in the underground mine openings could be expected, based on historical, geological, and engineering information. How It Works Bureau research has effectively demonstrated that stress changes within a rock mass can stimulate the development of cracks and fractures, resulting in the release of strain energy that generates seismic waves. These seismic waves, traveling outward from their source, can be detected, and the point of origin can be located in three-dimensional space. Furthermore, these seismic signals contain information that defines the source mechanism and the conditions between the source and the receiving sensor.

Jan 1, 1992

By Tony Mazzo

It has often been said by consulting engineers that foundation contractors are in the business of taking risks. One would agree that the mere fact a foundation project can be budgeted, planned, engineered and executed solely on the reliability of eight test borings made at a proposed site having an area of approximately 19,000 square feet, is a risky proposition, in and of itself. Now imagine that this site is actually one half of a city block located in an urban setting in an old, congested, historical neighborhood, surrounded by narrow city streets and historic landmark buildings. And suppose that the required depth of excavation for the construction of the new building on this site is approximately 35 feet and the natural groundwater table is at a depth below existing grade of only 25 feet. Given the difficult site conditions outlined above, one could certainly add the words "challenging" and "complicated" to the inherent word "risky" when describing the construction techniques involved to undertake a foundation project of this magnitude. This case study will discuss in detail how the excavation, sheeting, dewatering and underpinning work was accomplished as well as the problems overcome along the way.

Jan 1, 2003

By Sergio Estebanez, Martha Gross, Ruben Rubal, Yvonnick Rescamps, Alexandre Cochennec

The Hampton Roads Bridge-Tunnel (HRBT) Expansion project in coastal Virginia, USA will add two 1.5-mile (2.4 km) TBM bored tunnels alongside two existing immersed-tube tunnels between artificial islands. The site’s unusual constraints and the requirements of a large-diameter variable-density TBM shaped the design-builder’s decisions for handling TBM inputs and outputs, siting the TBM plant and supporting equipment, and sequencing tunnel-construction operations. This paper addresses the logistics necessary to enable key functions of the 46-ft (14-m) TBM and its ancillary equipment, including transport of most materials by barge, U-turn of the TBM on an artificial island, and delivery of materials for the second tunnel through the first one while interior structures are under construction.

Jun 13, 2021

By M. J. Shields

There are numerous suggestions in the literature on methods of obtaining representative samples of waste rock or mill tailings. Some suggested methods would result in thousands of samples and very high costs for a large facility. There is no general rule that can (or should) be followed, such as collection of a given number of samples per mass of material, per acre of impoundment, or per foot of drillcore. Each site is different, and the adequacy of sampling must be tailored to the site. A logical approach is to let the variability at the site dictate the number of samples that should be collected and analyzed, and then to quantify and evaluate the results by means of standard statistical methods.

Jan 1, 1998

By C. W. Vierrether

Mineralogical analysis contributes directly to the selection of applicable beneficiation techniques for a given site. Tentative remediation methods for use on the Sharon Steel tailings in Midvale, Salt lake County, UT, were determined in part by mineralogical characterization. A systematic characterization scheme was employed to identify mineral species, mineral associations, and grain size. This paper presents the mineral content and distribution data collected for site characterization. This data was used to determine areas that were representative of the total tailings at the Sharon Steel site. Although this was the main focus of characterization, other useful information was obtained. The approximate location of "old jig tails" was identified and insight on possible arsenic, mobility through the pile was also obtained from the mineralogical study.

Jan 1, 1991

By R. W. Chappell, M. W. Hills, R. L. Olsen

A stochastic approach was developed and applied to the Butte, Montana Hillside abandoned mining site for modeling stormwater runoff and subsequent receiving stream loadings. This approach enabled capture and quantification of the uncertainty associated with stormwater quality data and allowed the prediction of copper and zinc concentrations in the receiving stream caused by runoff from the Butte Hillside during storm events. Runoff flows and stormwater concentrations were input to the model as probability distribution functions. Monte Carlo simulation allowed prediction of expected instream concentrations in the form of cumulative distributions functions. The modeling results allowed evaluation of current best management practices (BMPs), targeting of future BMPs, and identification of key data gaps to fill during future sampling activities. This modeling approach is considered extendable to other active and inactive mining sites. Output from a model of this type is easily understood and can be used to communicate effective stormwater management to site regulators. Furthermore, application of this modeling approach will facilitate the development and implementation of a site-specific stormwater management plan and will optimize efforts to achieve standards for compliance with stormwater discharge permits.

Jan 1, 2002

By H. M. Friede

A short survey is given of the Iron Age smelting sites and smelting furnaces that have been found in South Africa. An attempt is made to classify South African smelting furnaces by the inclusion of functional characteristics such as the numbers and positions of tuyeres. An affinity is suggested between the Venda (eastern Transvaal) type of furnace and an East African type. The principles of the smelting process in South African Iron Age furnaces and the characteristics of the smelting products are discussed. Results of metallographic and chemical analyses of 19 iron specimens found at South African sites are given and compared with those from sites in Zimbabwe-Rhodesia, Mocambique, and Nigeria. The carburization and steeling of iron during primitive smelting and forging are discussed.

Jan 1, 1979

By J C. Macintosh

Capcoal Mine has modified its water use practices over the past 15 years. Two issues have changed the way water was managed:an economic review of water supply options for a planned expansion of the coal handling and preparation plant (CHPP) in the early 1990s, and increasing neighbour concerns about discharge of worked water from the mine into the local streams. These issues resulted in commitment by the site General Manager to cease discharge of worked water from site and to convert from using raw water to worked water in the CHPP. Operational needs, societal demands and continuing dry weather are again demanding change to the siteÆs water management strategy. This paper outlines the drivers for past and future operational change.

Jan 1, 2006

A survey of derelict and active alluvial tin and sapphire mines in the Emmaville area of northern N.S.W. as the first step in a pro- gramme of similar surveys to be undertaken throughout the State by the State Pollution Control Commission is presented. Thirty nine individual mine sites in the study area were included in the survey and an assessment made of the current level of impact on the environment at each site by assigning values of "magnitude" and "importance" to a number of impacting factors. Results are pre- sented in matrix form and mine sites ranked in order of impact "importance". Examples of alluvial tin, underground tin/arsenic and alluvial sapphire operations are discussed in detail and rehabilitation programmes proposed for implementation.

Jan 1, 1976

By Charles Berkey

CONTENTS PAGE C. P. Berkey-Responsibilites of the Geologist in Engineering Projects (with discussion) 4 Kirk Bryan-Problems Involved in the Geologic Examination of Sites for Dams 10 0. E. Meinzer-Relation of Ground-water Conditions to Leakage of Reservoirs (with discussion) 19 Charles Terzaghi-Effect of Miner Geologic Details on the Safety of Dams (with discussion) 31 G. H. Matthes-More and Better Geologic Data for Use in Hydraulic Projects (with discussion) 47 L. W. Fisher and R. D. Ohrenschall-Geologic Examination of Dam Sites in the Tennessee and Cumberland River Basins 60 C. K. Wentworth-The Geology of Dam Sites (with discussion) 78 L. C. Glenn-The Geology of Dams and Reservoirs 97 H. T. Stearns-Success and Failure of Reservoirs in Basalt (abstract) 111

Jan 1, 1929

The ~2500 km long Kermadec-Tonga arc northeast ofNew Zealand is the longest continuous intraoceanic arc in the world. At least 94 volcanic centres along the arc are submarine, most (87 per cent) within the Kermadec arc (de Ronde et al, 2003a). Volcanic rocks range from basalt to rhyodacite with trace element and isotopic data indicating significant magma source heterogeneity both along and across the arc.   The entire ~1300 km of the Kermadec arc has now been surveyed for hydrothermal emissions (de Ronde et al, 2004). First-stage surveys utilised surface vessels. In February 1996, the first sulfide samples from the southern Kermadec arc were dredged from the Brothers and Rumble II West caldera volcanoes (R/V Tangaroa cruise TAN96/03; Wright et al, 1998; de Ronde et al, 2003b). In September 1998, low-temperature, diffuse venting was discovered at Monowai, Rumble III and Clark volcanoes, and high-temperature, black smoker venting was found within Brothers caldera (R/V Sonne cruise SO-135; Stoffers et al, 1999). The NZAPLUME cruise of March 1999 surveyed 13 volcanic centres (each mainly comprised of single, large volcanoes) of the southern Kermadec arc and documented hydrothermal emissions above seven of them (de Ronde et al, 2001; Baker et al, 2003; Massoth et al, 2003). In July 2001, additional mineralised and hydrothermally altered samples were dredged from Brothers volcano (R/V Tangaroa cruise TAN01/07). The NZAPLUME II cruise of May 2002 confirmed venting was still occurring at all the known hydrothermal sites, and that ten active vent sites occurred along the mid-part of the arc, between Brothers and Raoul Island (de Ronde et al, 2002). In September-October 2004, NZAPLUME III surveyed the northern-most part of the Kermadec arc where another nine volcanic centres are hydrothermally active.   Second-stage exploration of the Kermadec arc hydrothermal systems utilised deep submergence vehicles. In October-November 2004, the Japanese submersible Shinkai 6500 made four dives on Brothers. Samples recovered include vent fluids, chimneys, altered rocks and various animals and microbes. In April-May 2005, a more extensive expedition using the American submersible Pisces V made 23 dives on nine different volcanic centres, eight of them for the first time.   Extensive plume surveys show Brothers volcano is host to the most hydrothermally active sites of all those known along the Kermadec arc. In total, nine dives have been made on Brothers, six on the NW caldera site and three on the cone site. The NW caldera vent site is a long-term hydrothermal system that is today dominated by evolved seawater but has had episodic injections of magmatic fluid. The cone site is a nascent magmatic-hydrothermal system where crack zones localise upwelling acidic waters (de Ronde et al, 2005). A SE caldera site represents the main upflow of a relatively well-established magmatic-hydrothermal system on the seafloor where sulfide-rich chimneys are extant. Each of these different vent sites represent diverse parts of an evolving hydrothermal system, any one of which may be typical of submarine volcanic arcs.

Jan 1, 2005

The National Institute for Occupational Safety and Health (NIOSH) conducted a monitoring field study to optimize the rib control plan in a room-and-pillar coal mine. The study mine is located in the Central Appalachia coal basin. Two monitoring sites were selected at different sections in the study mine. The selected sites have different overburden depths and geologies. The instrumentation plans at study sites include borehole pressure cells installed at various depths in studied pillars, rib and roof extensometers and load cells mounted on number of the rib bolts. The instrumentation results and observed geology for one of the study sites showed great potential for optimizing the rib bolt plan at that section of the mine. Therefore, a rib support optimization study was followed using numerical modeling technique. A calibrated threedimensional model was developed using the instrumentation results of the optimization section. The calibrated model was used to determine the optimum rib support for expected overburden depths and rib heights. Baseline rib bolt patterns were assumed for the optimization study. Additional rib bolts, above and beyond the baseline bolting parameters, were outlined and identified as solutions to contain the rib fracturing identified by the modeling results.

Jul 28, 2020

The Brothers hydrothermal system is host to two very contrasting vent fields and to date, is the only known example of this kind for any submarine arc volcano in the world. Firstly, there is the NW caldera field. It is perched on the caldera walls and is up to 1,200 years old, and represents a more ?mature? system dominated by water/rock interactions, though there is also evidence for magmatic contributions to the hydrothermal fluids. It is host to relatively high temperature (~300°C), focused venting of metal-rich fluids. Large Cu- and Zn-rich sulfide chimneys occur at this site, with high concentrations (up to 90 ppm) Au apparent in some chimneys. Vent fluids of the NW caldera site show sub-seafloor phase separation is occurring at this site. Silica concentrations in these vent fluids are consistent with the vent fluid temperatures. Secondly, there is the cone vent field that is much younger, and which sits atop the summits of a main cone (the Upper cone) and an adjacent satellite cone (the Lower cone) that occur inside the caldera, near the southern caldera walls. This field is dominated by S-rich vents with vent fluids more diffuse, lower in temperature (<120°C), very gassy and acidic (to pH 1.9), and relatively metal-poor. Fluids of the cone site have Mg and SO4 concentrations higher than seawater values, indicating these ions have been added to the hydrothermal fluid and are not being depleted via normal water/rock interactions. Variability occurs between the two cone vent fields, with the diffuse discharge observed at the Upper cone volumetrically small and chemically different from the Lower cone. For example, from the vent fluid Mn, Li, Rb, and Cs concentrations, it is apparent that the Lower cone has experienced a lower degree of water/rock interaction (i.e., more reaction) than the Upper cone. Vent fluid pH is higher for Lower cone, consistent with more reaction and neutralization of acidic gases. Fe/Mn is lower at the Lower cone due to decreased Fe solubility at the higher pH. The lowest pH sample (1.9) is from the Upper cone that has 39.4 mmol/kg of SO4, consistent with input of magmatic SO2 and disproportionation to sulfuric acid and S or H2S. Thus, the Upper cone site could be interpreted to have a shorter reaction path and residence time between the point of magmatic degassing and the seafloor venting than the Lower cone site. Isotopic compositions of the NW caldera and cone vent fluids show evidence for magmatic water with negative dD and d180 values, while 3He/4He values show the Brothers hydrothermal system has shifted towards more magmatic conditions over the past several years with both sites affected by magmatic events. Similarly, vent fluid sulfide d34S values and those for sulfide minerals from NE caldera chimneys also indicate disproportionation reactions involving magmatic SO2. Minerals such as chalcopyrite, bornite, chalcocite, covelllite and euhedral grains of hematite occurring in high temperature chimneys from the NW caldera site are consistent with a more oxidizing, magmatic fluid, while bulk sulfide geochemistry data show evidence for a higher temperature suite of elements (e,g., Mo, Co, Se) associated with Cu-rich chimneys. Gold mineralization occurs in these high temperature chimneys and is associated with the most recent deposition of high concentrations of Cu, where d34S values are most negative. Geophysical evidence suggests that the top of a magma chamber occurs ~2.5 km below the caldera floor, beneath the cone site in the SSE quadrant of the volcano. Very low velocities of <1 km-2 are seen in the seismic data between the magma and the seafloor, and are indicative of gas release. Harmonic tremor data provide evidence for a 500 m pipe-like ?conduit? located above the magma chamber (and below the cone), linking it with the overlying hydrothermal system, providing a mechanism for magma-derived metals to enter the hydrothermal system under the cone site. The NW caldera and cone sites are considered to represent stages along a continuum between magmatic-hydrothermal and water/rock-dominated end-members.

Jan 1, 2010