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By Jerry Rowe

There are numerous examples of historic and recent mines that have no closure system or have poorly designed closure systems. These mines may contaminate water resources, land resources and cause significant impacts to human health and the environment. As a result of these problems, many regulatory agencies around the world require that mine closure systems be implemented to manage ARD and protect water resources. In this sense, the paper discusses some of the key elements that need to be evaluated when selecting a mine closure system. These include the specific site climatic, hydrogeologic, hydrologic and geochemical conditions that must be considered for closure design. Two examples of innovative mine closure systems that have been implemented to take advantage of site specific conditions to effectively manage water are provided. The mine closure systems incorporate passive measures to control ARD (acid rock drainage) and protect water resources.

Sep 21, 2013

Numerical simulation for microseismicity due to mining at one of the collieries in Australia was carried out and the results were compared to the observed microscismicity. 3-D Stress analysis showed stress concentration on the edges of the mined areas and on the coal pillars- The stress concentration ahead of the coal face was biased to the tailgate. This is similar to the observed distribution of microseismic events. Stress reduction above and below the mined area was seen. Tensile stress was observed mainly above the mined area. It was realized that compressive failure due to nearly vertical maximum principal stress and nearly horizontal minimum principal stress in retreat direction (NS) might occur ahead of the face. Tensile failure due to nearly vertical minimum principal stress above the mined area was expected. Compressive failure due to nearly horizontal maximum principal stress in EW direction and nearly vertical minimum principal stress above and below the mined area were also expected.

Jan 1, 2001

The movements of the major continental cratons and the distribution of the principal tectonostratigraphic terranes are reviewed in the Circum-Pacific region during Phanerozoic time. It is concluded that major periods of orogeny and consolidation of accreted terranes in the Circum-Pacific region is best correlated with periods of advance of cratonic blocks over the Pacific Ocean basin combined with relative convergent to transpressive motions between the cratons and the Pacific Ocean plates. Continental collisions and collision of terranes with continental margins has not been a significant geodynamic process in Circum-Pacific tectonic evolution. The permanency of the Pacific Ocean basin throughout 500 MA is remarkable. It appears no continental block or large continental fragment has ever entered or crossed the Pacific Ocean basin since early Paleozoic time. This area where no continent has entered for 500 MA is almost coincident with the present Pacific Ocean basin and seems associated with the 25 to 100 meter geoid high which dominates the present-day figure of the Earth.

Jan 1, 1990

By Sidiney Nascimento Silva

O presente trabalho teve como principal objetivo avaliar, em escalas laboratorial e industrial, a viabilidade técnica e financeira da aplicação da escória de Aciaria LD (EAC), em combinação com a escória granulada de Alto-Forno (EAF), à produção de Cimento Portland CP III. O projeto de pesquisa em questão foi desenvolvido pela CSN, através de Convênio de Cooperação Técnica e Econômica com a Escola de Engenharia de Lorena, EEL, da Universidade de São Paulo, USP, e compreendeu as seguintes etapas: i) caracterização físico-química e mineralógica da escória de Aciaria LD da CSN; ii) desenvolvimento do processo adicional de beneficiamento da EAC para aplicação na produção de cimento; iii) testes laboratoriais visando a avaliar a viabilidade técnica; iv) testes industriais com a finalidade de validar os testes laboratoriais e selecionar a formulação de melhor desempenho; v) estudo de viabilidade financeira; e vi) implantação do projeto. A aplicação da escória de Aciaria LD da CSN na produção de Cimento Portland CP III, em combinação com a escória de Alto-Forno e clínquer, é viável técnica e financeiramente. Isso traz reflexos positivos para o aumento da competitividade do negócio Cimento, aumenta a recuperação de metálicos para reciclagem nos processos siderúrgicos da UPV (negócio Siderurgia) e reduz passivos ambientais.

Aug 16, 2017

By Black PM, Itaya T

Arc-type volcanic activity has been a major feature of the late Cenozoic geological evolution of the Pacific-Australian plate boundary in the northern New Zealand region. The timelspace distribution patterns of arc-type rocks reflect changes in the nature of the plate boundary as it has evolved. Inception of volcanism began in the north during earliest Miocene times (26 Ma) following ophiolite emplacement and during the next 10 Ma developed into a volcanic arc segment extending south to the present position of the central North Island. The northern part of the arc became extinct about 15 Ma ago, but activity continued in the central (Coromandel) part of the arc until about 5 Ma ago. In late Pliocene and Quaternary times volcanic activity has become concentrated in a northeast trending zone which is collinear with the Tonga-Kermadec Arc.

Jan 1, 1995

By Raymond J. Poletto

This paper describes the special problems that occur with the construction of diaphragm walls and discusses the lessons learned during the repairs of structural walls. Although diaphragm or slurry wall technology and equipment has vastly improved since its development in the late 1950?s, significant problems still occur. Key issues are repairs related to panel joints between wall panels, concrete defects associated with tremie concrete problems, leaks and other defects at tieback reservations or inserts, wall leaks within the plane of the wall and surface repairs. The paper supports the position that diaphragm walls are relatively watertight when properly constructed, but cautions that it is necessary to address potential problems in the design stage and allow for flexibility in construction so that the problems that occur can be corrected once encountered. Due to the fast track nature of most projects the time available for design, detailing and construction is limited. As a result, insufficient attention to detail by any of the responsible parties can lead to imperfections and defects in the wall. The authors describe the nature of these problems and their potential resolution based on ?lessons learned.? The timely response to wall problems is essential to the successful completion of a diaphragm wall project. Appropriate repairs have resulted in largely successful jobs starting with the World Trade Center in New York City. The authors? total 80 years of experience as the engineer of record and designer, inspector and contractor?s representative for the diaphragm wall results in a unique insight to deal with these problems.

Jan 1, 2011

By Kenneth Eltschlager

Blasting represents the highest risk of any surface coal mining activity that could result in injury and/or property damage off the permit area. In addition, blasting related issues e.g. flyrock, vibrations, air blast, etc., are responsible for a large percentage of citizen complaints. Thorough and consistent regulation of individuals certified to conduct blasting by the Office of Surface Mining Reclamation and Enforcement in Federal Program states and on Indian Lands under Federal jurisdiction is vital, as it serves to: facilitate coal production to meet the nation’s energy needs; protect people and property on and adjacent to Federal mining permits; form a basis for states to grant reciprocity certificates to Federal blasters; and be a positive example to primacy states. OSM issues Federal blaster certificates for blasting on Federal surface coal mine permits. The certification program includes experience, training and testing components similar to many of the states. But where a state program may focus on the specific blasting applications within its boundary, the OSM certificate requires a very diverse test to cover all potential blasting applications and products across the nation. Therefore, the Federal certificate is a good surface mining credential for blasters anywhere in the United States.

Jan 1, 2010

The Australian Coal Combustion Testing and Research Facility has been operating commercially for one year and during that period coal product evaluations have been conducted on behalf of four coal companies and one electricity commission. The facility is equipped to assess the behaviour of steaming coal in milling, combustion (including flame stability, burnout and heat transfer), ash deposition and erosion, fly ash collection and gaseous emissions. The relevance of the results of the pilot testing to industrial practice was demonstrated during the calibration of the facility using four coals burnt in Australian power stations. The calibration coals were from the Tarong and Gladstone Power Stations in Queensland, tluja Power Station in Western Australia and Bayswater Power Station in New South Wales. Also an opportunity arose to visit an overseas power station to observe a full scale test burn using one of the early coals tested on a commercial basis in the combustion test facility. The calibration trials showed excellent agreement with industrial coal performance in t:orms of flame stability, turndown, carbon burnout and gaseous emissions. Encouraging correlations were also found in the case of furnace radiation, boiler deposits (slagging and fouling) and electrostatic precipitation. In the case of the last group the only real reservations about the correlations are due to the non-availability or qualitative nature of results collected around the power stations. In all cases there is a high degree of confidence in the facility's ability to predict the relative performance of different coals and in some cases direct numerical predictions can be Made.

Jan 1, 1987

By Stephen M. Voynick

Two hours driving time west of Denver, CO and 21 km (13 miles) north of Leadville, Bartlett Mountain rises 4,065 m (13,337 ft) high in central Colorado's Tenmile Range. Bartlett Mountain is one of Colorado's most recognizable peaks, especially when the late afternoon sun casts a surreal, reddish light across its most prominent feature - the Glory Hole. This is a gaping, half-mile-wide, 245-m- (800-ft-) deep crater. Created by subsidence from 60 years of massive underground mining, the Glory Hole is a monument to the Climax Mine, one of the great achievements in American mining and metallurgy. For most of this century, the name Climax has been synonymous with brilliant mining engineering, innovative metallurgical research and entrepreneurial promotion of a once-obscure metal - molybdenum. Climax overcame an array of economic, technological and social problems to become a model for underground development of massive deposits of low-grade ores. It is one of the few mines in the world where cumulative production is measured in the billions of dollars. The Climax mineralization was emplaced 30 million years ago. Magmatic intrusions formed a large, mineralized stockwork within the granite country rock of Bartlett Mountain. Associated hydrothermal events forced superheated metal- and quartz-rich solutions through fracture zones, silicifying the country rock and depositing huge amounts of molybdenite, or molybdenum disulfide. The mineralized rock, a light gray, finely crystalline, silicified granite, is laced throughout with blue-gray quartz veinlets containing molybdenite. Although the richest ores graded only about 1% molybdenite, the Bartlett Mountain deposit contained more than 2.7 Mt (3 million st) of elemental mo- lybdenum.

Jan 1, 1997

By L. S. Gormely

El presente texto describe el desarrollo del proceso de lixiviación adecuado en canchas para un yacimiento en óxidos de cobre. La lixiviación en canchas es una alternativa de tratamiento útil que se considera para aquellos óxidos cuya ley sea demasiado baja para procesarlos por trituración fina y lixiviación por agitación y que presenten dificultades técnicas para someterlos a lixiviación en tinas. Así, en el sistema de canchas, la lixiviación será más rápida y más eficiente que en una simple lixiviación en pilas.

Jan 1, 1980

In 2007, a total of 2,030 coal mining operations reported employment to the Mine Safety and Health Administration (MSHA).1 Coal mines comprised 13.7% of all mining operations. ? Bituminous mines comprised 92.4% (n=1,875) and anthracite mines 7.6% (n=155) of coal mining operations. ? Approximately 72% of all coal mines were located in three states: Kentucky (28.4%), West Virginia (22.6%), and Pennsylvania (20.5%).

Aug 1, 2009

Traditionally, the development of a mineral resource project goes through a fairly set pattern of decisions from what commodities to search for; where to look; how to locate; what are the reserves; how can they be exploited with optimum returns for all stakeholders; where are the markets and what will be the price received; what financing arrangments? However, due to the unique nature of most mineral resource properties, the relative significance of individual parameters on the ultimate development decision will vary from project to project. Sensitivity analysis in its formal sense is most frequently related to the economic analysis of a project particularly in conjunction with the ultimate development decision making process, and acknowledges the uncertainty of the actual values with their impact on the corporate decision making yardsticks. In many cases, this analysis merely adds more values to confuse the decision makers who may well opt for some subjective rationale to overcome the numeric confusion. However, sensitivity analysis should be used more frequently to exploit the development dollar to its maximum, THROUGHOUT the phases leading to the development decision. It is essential to identify the critical inputs to the various decision tiers in a project as early as possible and direct the funds to ensure that these parameters are determined as accurately as possible. Examples are used to illustrate the need for an even-handed quantification of the parameters which affect the outcome of decisions en route to the final one while minimising the risk in making an optimum assessment in relation to development funds Available.

Jan 1, 1983

By P Salmon, M Kennedy

Sun Metals Corporation Pty Ltd (SMC), a wholly owned subsidiary of Korea Zinc Co Ltd (KZC) is a company formed to develop, construct and operate a zinc refinery, 11 km south of Townsville in North Queensland. The project opportunity exists because of on-going consumption growth for refined zinc metal, technological, environmental and economic obsolescence of existing zinc processing plants, and a prolonged ædroughtÆ of new zinc processing capacity under construction. The Project will utilise proven technology developed by KZC at the Onsan refinery in Korea. The Townsville Refinery has been designed to be the most environmentally-friendly zinc refinery in the world, and in particular to resolve the issue of secure, long term treatment of the ironbearing content of the zinc raw materials.

Jan 1, 1998

United Engineering Trustees, Inc. GEORGE D. BARRON ARTHUR S. DWIGHT R. M. ROOSEVELT The Engineering Foundation H. C. BELLINGER E. DEGOLYER J. V. N. DORR

Jan 1, 1932

By A. C. Ackenhell

The geologic environment of Pittsburgh, Pennsylvania is both inviting and challenging to drilled pier installation. The shales and clayey soil zone of the hills are favorable but the alluvial soils of the three major rivers create problems. Beginning in the early 1950's, drilled pier installation continually improved as methods were developed to meet the geologic challenge. Case histories are presented to illustrate the historical development of piers in Pittsburgh. Recent innovations reducing the groundwater problem are illustrated by a case history of a high rise building construction. Load test information for side wall shear on the cylindrical shaft area between the concrete and bedrock continues to be desired but remains generally uneconomical.

Jan 1, 2010

By Segundo Bejarano R

Durante mucho tiempo los métodos tradicionales utilizados en la ejecución de los proyectos en el sector minero han sido insuficientes. Por ello, la minería optó por emplear técnicas modernas de planificación y control que ahorren tiempo y minimizen recursos como mano de obra, maquinarias, energía y otros. En este sentido, el objeto del texto es describir el uso del método PERT-CPM en la ejecución del proyecto minero, así como señala su aplicación práctica en el proyecto de ampliación que viene ejecutando la compañía de minas Orcopampa.

Nov 24, 1986

By Ivette E. Torres

World investment 10 all mineral and mining industry sectors is not available. However, partial information available provides some information useful for analysis. Information available in this section covers limited geographic information on investment in the steel industry, limited information for petroleum industry capital spending, and total U.S. foreign investment in comparison to the mineral-related sectors (tables 13, 14, and 15). Annual steel industry investment is available for the European Community, almost all countries within the European Free Trade Association (EFTA), Latin America, and other countries with significant mineral industries, such as Canada, Japan, and the United States. Although information was not available for 1992, data for 1991 indicate that for those countries aforementioned, total investment increased by 8 %. However, investment patterns were very different within the different groups of countries. While the European Community had a net increase of 12 %, dominated by an almost °40 % increase in Germany, EFTA member countries had a 26 % decrease in investment for the same period. Investment in EC countries was almost seven times that of EFT A countries. Japan's investment in the iron and steel industry, by far the largest of those available, almost twice that of the EC and almost four times that of the United States, increased by more than 20 %. In North America, investment in Canada and the United States decreased. Almost all of Latin America decreased investment in the sector. The notable exception was Mexico, with a 60 % increase. Changes in Mexico's investment policies of the recent past, its economic growth, and privatization of its iron and steel industry are some of the reasons for such an increase. The other country covered individually in Latin America, where investment in the iron and steel industry increased, although slightly, was Argentina. This limited information does not allow a comprehensive analysis of global industry trend, which in turn impacts many other mineral commodities, and with the transition in many countries within Europe and Central Eurasia that are now effecting the steel industries of the countries that were members of the U.S.S.R. and its CMEA partners, it is most regrettable that comprehensive and comparable data, both current and historic, on investment in this area are not available.

Jan 1, 1994

By Everard Leland

This paper, describing the mining practices at the Pilares mine, Pilares de Nacozari, Sonora, Mexico, is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts. At present (1930) practically all the mineral production from the Nacozari district is from the Pilares mine of the Moctezuma Copper Co., a subsidiary of the Phelps Dodge Corporation. The ore is mined for its copper but contains associated silver in small quantities.

Jan 1, 1930

By Robert Stefanko

13.1-SUBSIDENCE AND GROUND MOVEMENT ROBERT STEFANKO 13.1.1-SUBSIDENCE AND FAILURE This treatment of subsidence and ground movement will be confined to subsidence control for limiting surface damage by assessing the significant parameters affecting ground movements during mining to optimize mining techniques. The material will be equally applicable to evaporite mining as well as coal but will not deal with block caving or similar systems where failure is deliberately induced and surface protection is not necessary or provided. When an underground opening is established, the original equilibrium is disturbed with resultant stress concentrations. While many factors are involved in opening stability, the span (W) undoubtedly is one of the most important factors in failure. Assuming it is relatively small, the overlying rock strata can bridge across the opening and little if any movement or convergence of top and bottom will occur. However, as the span increases, a point is reached where the stress in the overlying rock strata exceeds some strength value of the rock, and the top breaks. If the opening span is limited to some subcritical value (-We) and/or is at great depth (D), a pseudo-arch will form, achielring stability before rupture occurs to the surface. The boundary of this arch is thought to approximate an ellipse in form with the major axis vertical and equal to four times W, although there has been little field research to substantiate this theory. However, if the width of this opening is increased at this horizon to some critical value (W,) or the same span is created in a shallower seam, the overlying strata ill progressively rupture to the surface and the characteristic subsidence trough is formed (Fig. 13-1) The area of the surface affected is much greater than the area of the seam extracted, depending on the "angle of draw" (a), which is the angle between a vertical line from the edge of the opening and another line extended to a point at which subsidence tails out to zero. This angle has been found to be about 35° in Europe but is rather academic, being a function of instrument precision in detecting subsidence. Since the subsidence effect is so small at any point beyond n 25° angle, this latter may be considered the practical limit of subsidence. Further- more, indications are that the angle of draw varies with depth and nature of the strata.' In a field study over a 1,000-ft-deep potash mine in New Mexico, the maximum angle of draw was found to be 51.5°.2 So far, only a single opening has been considered. However, the width of the excavation applies to any complex mining system of entries, rooms and longwalls as long as the seam has been fully extracted and the width represents the distance from one solid rib to another. It will be noted that the amount of vertical displacement varies from point to point on the surface (s), but the maximum subsidence for a given trough occurs at the center (S). This latter value may not he equal to the maximum possible subsidence (Sm) which occurs only if a critical or super- critical (+W,) width has been exceeded (Fig. 13-1). Substantial surface damage can result when subsidence occurs. Factors affecting the amount and type of ground movement are: thickness and properties of the seam, angle of draw, width of excavation, depth and type of overburden, inclinations of strata and surface, and the amount of support left in the gob. In Europe,

Jan 1, 1973

By Saieb Haddad, Henry Pate

"Building retaining walls in an urban area is becoming more diffi cult due to right-of-way restraints. Using standard concrete cantilever walls requires a construction easement behind the walls for installation, which for the most part is unavailable. To install these types of walls in a limited right-of-way requires extensive temporary walls to minimize the construction easement. Top-down construction walls utilizing tie-back anchors for support require either the purchase of the right-of-way or underground easements in the area of the anchors.These problems faced the Department on Interstate 75 widening in Knoxville, TN in an area of a large cut. A multi-story Insurance Building and a large commercial Retail Center were located at the top of the cut. To prevent any impact on the buildings, the walls had to be placed within a limited area. The option of buying the properties was prohibitively expensive. Due to the height of the two walls and the variability of the underling rock line, contiguous caisson pile cantilever walls were contemplated as the only wall type that would be appropriate. The cost of the two walls was estimated to be very close or even higher than the cost of purchasing the two buildings. The Department believed that there must be a better way to deal with the problem. A vertically tied-down pile frame wall constructed from the top-down with a concrete facing was developed. This allowed the construction of the walls to be restricted to the available limited area and provided substantial savings for the State. INTRODUCTIONThe widening of I-40/75 has been a major transportation project in the Knoxville area which is being constructed by the Tennessee Department of Transportation. The project includes 18 Retaining Walls and 13 Bridges. Two of the 18 Retaining Walls, refer to Figure 1, are to support two valuable properties, one being an insurance company housed in a multi-story offi ce building and the other a suburban shopping center which were appraised at $13.0 million and $5.0 million respectively. Due to the 31 ft. (9.5m) maximum height of each of the two Retaining Walls and the limited Right-of- Way of 15.0 feet (4.6m), a contiguous caisson pile cantilever wall was proposed for each of the two retaining wall sites with an estimated cost of $12.0 million each. The contiguous pile cantilever Wall is comprised of a line of caisson piles socketed into underlying competent bedrock. The design required that 4 ft. (1219mm) dia. piles be installed at 6 ft. (1.83m) centers, socketed into rock in order to provide lateral stability and restrict lateral wall movement to acceptable limits. The line of caissons would be fronted with a cast-in-place concrete face wall."

Jan 1, 2007