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By Colonel Oattis E. Parks

The quantity of coal recovered by diamond coring techniques is not sufficient in many instances to make meaningful coking and/or ash fouling tests. Quantities in excess of that obtained by conventional coring techniques, usually in amounts exceeding 500 pounds, has been designated bulk sampling. During the past three years, AMAX Coal Company has utilized five methods of bulk sampling. It was our desire to obtain a bulk sample that was diagnostic of the seam by the most expedient and economical method. From the beginning all of our efforts have been directed to methods which would extract the required coal from slim boreholes which provide quick and inexpensive access to the coal seam, regardless of depth, terrain and accessability. In our efforts and investigation several large diameter cores have been taken from thick coal seams at relatively shallow depths in easily drilled rocks. On the other hand, for deeper thin seams multiple large diameter coring is more expensive and time consuming. It is somewhat less expensive when multiple cores are taken from a single slim borehole utilizing deflection coring, although considerable skill is necessary.

Jan 1, 1973

By M. D. Johnson

The San Andres mine, located in the western mountain region of Honduras, Central America, contains epithermal gold mineralization as disseminations, in quartz-chalcedonic veins and stockworks. Host rocks include a thick sequence of Cretaceous to Tertiary conglomerates, sandstones, rhyodacite tuffs and andesites. Mineralization is controlled by northwest and northeast striking, normal faults and fractures which dip steeply east and west. Currently, 500 STPD of 1. 93 Grams/MT gold ore is being open-pit mined from the conglomerate and andesite. The mine is at the west end of a mineralized zone that can be traced over an area of approximately 1.5 square kilometers.

Jan 1, 1993

By Jack Parker

Cycles of mine convergence coincide with annual cycles of temperature and humidity in the mine. Laboratory measurements confirm that the presence of moisture reduces rock strength and induces internal rock stress. Findings are used in the design of mine openings.

Jan 1, 1969

By Stephen Stone, Kerby Dobbs, G. Richard Whittecar, W. Lee Daniels, Zach Agioutantis, Tess Thompson

A common result of Environmental Impact Assessments associated with mining projects is the construction of new wetlands in areas disturbed by mining operations. Where appropriate, this mitigation may be considered an integral part of the mine reclamation process under the principles of sustainable development in the minerals industry. Wetbud is a new tool for estimating wetland water budgets using available weather data and site-specific topographic, soil and geohydrologic data, coupled with mass balance mathematics. Wetbud is primarily intended as a planning tool for use in the design of created wetlands, but it can also be applied to native wetlands or wetland restoration sites where the required input parameters can be specified. Wetbud can be run in its basic form where wetland topography, soil parameters and groundwater flux are simplified, or in the advanced form, where these parameters are included in a more complex approach via integration of the MODFLOW package, a free 3D program that was developed by the United States Geological Survey. Both versions can also include overbank flow hydrology sources and the advanced form can also model sloping and irregular topography. The program downloads weather data from the nearest applicable station and selects appropriate wet-normal-dry (W-N-D) years following a modest user data clean-up step. Wetbud also has the ability to utilize existing short-term (e.g. 6 to 9 months) groundwater data from an up-gradient well to simulate longer-term groundwater level inputs for the selected W-N-D years. In addition, Wetbud features a “Wizard” version that comes pre-loaded with 14 pre-selected weather data sets for all areas of Virginia that can develop a simple monthly water budget in less than 15 minutes – a feature that could be expanded anywhere geographically with historic weather data.

Jan 1, 2017

By E. J. Rorem

Rockfall and unstable rock slopes can be con-trolled by using steel wire-rope net systems as barriers or as slope draping. The chief advantage of such systems over rigid type barriers is the flexibility of wire rope netting. This flexibility and strength permits kinetic energy dissipation with low maintenance requirements. Mining activities can produce temporary or long-term unnatural slopes and unstable rock faces that may produce rockfall hazards. Such conditions can necessitate efforts to minimize the hazard to workers, structures and equipment.

Jan 1, 1996

By W. Gibson Jaworek

It has become apparent in recent years to everyone intimately concerned with the future of the American fuels industries that the growth in demand for energy has become a topic receiving considerable attention, and that investigators are leaning more and more toward a mathematical approach to deduce what pattern that growth will follow. Though coal has been included by necessity In all-studies of future energy markets, it has not been the subject of mathematical analysis or description as frequently as has been total energy or some of the other fuels, particularly petroleum, It is the intent in this particular paper, to subject bituminous coal consumption to a preliminary mathematical scrutiny which can lead to a more logical estimation of the general level of bituminous coal consumption for the next decade, as well as formulating an approach toward describing how coal consumption may vary as the result of the annual variations in activity in the United States, economy, The approach utilized is more sophisticated than the mere projection of the historical trend of bituminous coal consumption. Such a projection would lead to a continuation of the recent decline, indicating that coal consumption would reach zero some thirty years from now. On the other hand, the mathematical analysis described here is a relatively simple, straightforward approach and- is not intended to represent the-ultimate in mathematical economic analysis as now practiced, It is hoped that this will contribute to our knowledge of bituminous coal markets. Even more, it is hoped that it will help arouse a greater interestin utilizing mathematical and statistical analysis when studying the bituminous coal industry. - Since this is a preliminary study, comments and criticisms are anticipated.

Jan 1, 1960

Published by ?MILOS CONFERENCE CENTER ? GEORGE ELIOPOULOS? Editor Professor Z. AGIOUTANTIS Editorial Coordinator HELIOTOPOS ? PROFESSIONAL CONGRESS ORGANIZERS Layout IRINI KALOGIRU Production PALLAS Co Cover PANAYOTIS PAPASTAMATIS HELIOTOPOS - PROFESSIONAL CONGRESS ORGANIZERS

Jan 1, 2003

By C. P. Mangelsdorf, Richard A. Allwes

At the request of the U.S. Department of Labor, Mine Safety and Health Administration (MSHA), the U.S. Bureau of Mines evaluated the suitability of using tri-sets for protecting mine personnel in roof-fall prone areas. A steel-set arch provided by MSHA served as a basis for evaluating the performance of the tri- set. All tests and analyses were conducted according to the arch canopy test and design procedures developed by the Bureau. Theoretical resistance functions were established for the steel-set arch and tri-set and were representative of their experimental behavior. The resistance functions were used to determine the energy absorption capacity of the structures and to predict their dynamic response to impact loading. The dynamic tests demonstrated that the arch canopy design procedure is appropriate for tri -sets and yields conservative designs for both steel-set arches and tri-sets. As a result of this work, it is recommended that tri-sets may be considered for protection against roof falls, provided that the arch canopy design procedure is utilized for each application and that the principles underlying the design procedure are understood.

Jan 1, 1992

By Dirk van Zyl

Three conditions are required for a risk to be realized: (1) a source of risk (i.e., hazard) must exists (2) some process must take place which will lead to the exposure of people, animals, and/or the environment to the hazard: and (3) as a result of the expense, undesirable effects are produced on the people, animals, and/or the environment. A comprehensive risk assessment addresses all three of the conditions through the following four steps: (1) risk source (hazard) characterization, (2) exposure assessment, (3) dose-response assessment, and (4) risk estimation. Although the terminology may differ, the overall approach of financial, public health, and environmental risk assessments is the same (National Science Foundation, 1985).

Jan 1, 1988

By V. O. Tenorio, J. Puell

"Dump design is critical to effective mine planning in large scale open pit mines. Capital and haulage costs are considerable from early stages and through the life-of-mine as these dumps gradually become immense structures. Delivered mining rates, as well as certain spatial and physical constraints, provide a set of parameters of mathematical and economic relationship that creates opportunities for modeling and thus facilitates the measuring and optimization of ultimate dump design by using programming and empirical techniques while achieving economic objectives. This paper presents a methodology to optimize the ultimate dump design by minimizing its total dumping costs. The methodology consists of the formulation of a generalized model based on the relationship of the main dump parameters, followed by the use of linear programming to find the solution that minimizes the haulage total cost, and finally through a series of iterations, modifies the preliminary solution by projecting it to the topography and creating the ultimate dump design. A case study applied to a waste dump exemplifies this methodology. INTRODUCTION Open pit mine operations move large amounts of material on a daily basis from the shovel faces to the appropriate destination points. Hustrulid et al. identified three major destination places where the material receives downstream treatment after its delivery: mill processing, leaching dumps, and waste rock dumps [1]. The corresponding destination is given by a cut-off grade criteria, ore type, and the possibility of obtaining the maximum metal recovery. Dump leaching technologies have developed substantially since 1975 [2], and have enabled mining facilities to beneficiate low grade sulfide and oxide ores. As a consequence, the number of active dumps have increased since then and the entire mine configuration, which is limited in itself, has changed. The proper location, design, and construction of a mine dump must serve the safety, environmental and economic goals of the long-range mine plans. Therefore, an optimized use of the available surface area in the mine is highly desired."

Jan 1, 2018

By Christian Maguire

Tunnel contracts in New York have in recent years had few bidders with the bids received being much higher than anticipated. Since 9/11, security has become a key issue in planning key infrastructure projects in New York. This is especially true in the case of large water supply tunnels. Striking the right balance between cost and security was the major factor in determining the best configurationfor the Kensico-City Tunnel. This paper outlines the efforts made to determine realistic probable bid costs for the tunnel contracts, and the innovative approaches taken to deal with security issues.

By T. Negeri

Flotation is the most efficient and preferred solid-solid separation method in mineral processing. However, enhanced production of high-grade concentrates at sufficiently high recovery still poses technological challenges to-day. A novel flotation method to produce final-grade concentrates from finely-ground ores in a single step is being developed and tested by CANMET. For the complex sulphide ores tested, grades are superior while recovery is considerably improved. Furthermore, concentrate production rates, at similar recoveries, are faster than for the conventional rougher-scavenger-cleaner configuration. This paper discusses the physical operating parameters affecting Cu-Zn flotation metallurgy.

Jan 1, 1995

By Andreas G. Mueller

Gold-silver and copper-gold deposits with high-temperature wallrock alteration of Ca-Mg-Fe-Al silicates occur in ca. 3.0 Ga old greenstone belts of the Yilgarn Block, Western Australia. The deposits are hosted by amphibolite-facies komatiites, basalts and BIF, controlled by ductile shear zones and located within the contact-metamorphic aureoles of composite granodiorite-granite batholiths. Disseminated sulfides and free gold form foliation-parallel ore zones in a gangue of anhydrous silicates (garnet, clinopyroxene, olivine), hydrous silicates (amphibole, biotite) and calcite. The deposits may be classified on the basis of their dominant economic metals as: 1(1) Gold skarns with substantial silver as by-product, represented by the Marvel Loch mine (production: 2,200,000 t at 3.5 g/t Au), and characterized by the mineral association pyrrhotite, loellingite, arsenopyrite, galena, gold and magnetite. (2) Gold skarns with low silver contents, represented by the Nevoria mine (production:1,850,000 t at 3.4 g/t Au), and characterized by the mineral association pyrrhotite, chalcopyrite, arsenopyrite, gold, Bi-tellurides and magnetite. (3) Copper-gold skarns, represented by the Elverdton mine (production: 850,000 t at .7 5 Cu, 0.81 g/t Au), and characterized by the mineral association magnetite, chalcopyrite, pyrrhotite, pyrite, gold and Ag-Bi tellurides.

Jan 1, 1990

By Jeanne A. Zimmer, Andrew B. Cecala, Edward D. Thimons

The Bureau of Mines performed a study to determine optimal locations for longwall face methane monitoring equipment. Longwall face ignitions continue to be a concern to the U. S. coal mining industry. Gains in ignition control technology have been somewhat negated by advances in longwall productivity. More reliable, heavy-duty longwall face systems generate higher production rates and increase methane liberation rates. These rates will likely continue to rise in the future as further coal production increases occur. Efforts will continue in the areas of methane drainage, methane containment, and methane dilution. In addition, more effective face methane monitoring is needed. As technology continues toward automated longwall panels, the importance of monitoring for methane at the shearer becomes even more significant. Since the primary face ignition source is the shearer mining machine, the Bureau ran tests to determine the best location to take methane readings on the shearer. This information, in conjunction with data obtained from field studies, provides a knowledge base for selecting optimum face methane monitoring locations. INTRODUCTION Face ignitions are a concern for many U. S. longwalls and will continue to be until better control technology can be developed or until reliable and accurate knowledge can be provided as to when an explosive concentration is present. Figure 1 shows the number of reported U. S. underground longwall ignitions from 1980 to 1990. The number of longwall panels have remained relatively constant over this time period with 89 reported in 1980, compared to 96 in 1990. In spite of technological improvements in mining over the past decade, no significant reduction in the number of longwall face ignitions has occurred. One factor contributing to this is that the U. S. coal industry is mining gassier seams causing methane liberation rates on the average to be higher (Trevits, 1991; Grau, 1987). Another factor is the development and implementation of more reliable, heavy-duty longwall face systems that are generating higher production rates and higher methane liberation rates. Additionally, the average panel width in 1991 was 714 ft; a 44 pct increase from 1980 when faces averaged a width of 495 ft (Merritt, 1992). Increases in panel width also impact total face methane emissions. [ ] There have been substantial advances in control technology in the areas of methane drainage, methane containment, and methane dilution. In some mines, efforts to drain methane in advance of mining have proven effective, but geological conditions often preclude this approach (McCall, 1984; Ely, 1989). In other cases, ventilation air quantities of over 100,000 ft3/min and face velocities of over 1,000 ft/min have been implemented on longwall panels. Other operations have implemented anti-ignition spray systems which use water sprays behind each cutting bit to quench the hot streaks created from cutting noncoal materials (Courtney, 1990). Other control techniques, such as the modified shearer clearer system and ventilated drum, have been used to increase the amount of turbulence and ventilation around the cutting drums, thus reducing methane levels (Cecala, 1986; Divers, 1987).

Jan 1, 1993

By F. Grajales Munoz

The Cienega project, now under construction by Penoles group, is located in the mountains of the State of Durango, Mexico. The gold and silver deposits are found in the 4-km long system of veins, which will be extracted by underground methods. The planned 1000 tpd process plant will contain a countercurrent cyanide circuit for oxide ore and a flotation circuit for sulfide ore. Considerable resources have been devoted to development of infrastructure in the isolated location, as well as for the mitigation of environmental impacts. Startup is scheduled for the third quarter of 1994.

Jan 1, 1994

By Edwin B. Wilson

Electric power generation remains the greatest market for coal in the United States. In 1967, about 272 million tons of coal, amounting to over 51 percent of total coal consumption, were burned to satisfy this nation's hugh demand for power. The size of the utility market is currently five times that of 1941 and continues to grow with the demand for more and more energy. A major reason for this strong market has been the ability of the coal industry to supply a superior product for combustion while maintaining competitive prices. Now that the coal industry is engaged in intensive competition with nuclear power for future energy demand, it becomes ever more imperative that superior coal products are produced. One important problem when burning some coals is a liquid phase corrosive attack on boiler tube metal in the superheater and reheater areas of the furnace where steam temperatures may exceed 1050°F.

Jan 1, 1969

By E. R. Reeves

The mining industry has recognized the importance of engineering controls as a primary means of preventing hearing loss. The noise control treatments most commonly observed on drills and bolters during this study were windshields, sound absorbing material, and hydraulic motor covers. These controls were evaluated on machines at underground metal mines to determine the amount of noise reduction achieved by each control. The results indicate that absorbing material has very little effect on the noise level. The noise reduction attributable to the motor covers was dependent on the material used to create the cover. Properly installed windshields were the most consistent control.

Jan 1, 2004

By Werner Bilfinger, Claudio Nahas, Marcelo Waimberg

"INTRODUCTION The so called Porto Maravilha Project consists of the re-urbanization of a 500 ha area in the Rio de Janeiro port region. Several changes in local infrastructure are being implemented, including a significant change in the road system, with the demolition of the former “Via Perimetral” viaduct and construction of 4 new tunnels: • Saúde tunnel - 35 m long (Waimberg et al, 2014); • “Binária tunnel” - 1012 m long; • “Via Expressa” twin tunnels - 1850 m long each way. The tunnels were excavated almost completely in rock using conventional drill and blast methodology and only some short stretches in weathered rock, associated to faults zones, residual soils and marine sediments close to the tunnel portals. During excavation of access shaft and “Via Expressa” and “Binária” tunnels significant ground settlements as well as settlements of buildings founded both on shallow and deep foundations were measured. These values could not be associated to conventional tunneling induced settlement troughs. This paper focuses on the “Via Expressa” tunnels, presenting a brief description of the project as a whole, its geological and geotechnical background, monitoring results, and a discussion of possible causes of the measured settlements. PROJECT DESCRIPTION The Porto Maravilha Project is an integrated multidisciplinary action on behalf of the Rio de Janeiro city council with support from the State and Federal Governments. In addition to creating new conditions for working, housing, transport, culture and leisure for the resident population, it also promotes expressive economic development in the region (Portonovo, 2015). Porto Maravilha Project is carrying out actions for the recovery of the region’s historical heritage, as well as promoting the population´s social and economic development. One of the main benefits of the Porto Maravilha Project is the construction of the new traffic system in the port area, consisting of the Express and Binário roadways. The new project, which will replace the current Perimetral Rodrigues Alves viaduct system, will increase traffic flow capacity by 27%."

Jan 1, 2016

By H. Kinilakodi

The authors previously developed a methodology that combines injury and citation measures into an overall mine safety performance evaluation tool, called the safe performance index (SPI). It can be easily adopted by mine operators to monitor trends in their injury and citation experiences as a risk assessment method. In this paper, six normalized safety measures and the SPI are used to evaluate the health and safety risk that existed at mines in the two years preceding the occurrence of a fatality. The percentage of mines is given for which the risk was high or where trends of some of the safety measures indicated moderate risk. In 50% of the mines, this mine safety performance tracking method could have been helpful to the companies, state agency or the U.S. Mine Safety and Health Administration (MSHA) in recognizing and addressing emerging problems with actions that may have been able to predict high-risk conditions, the fatality and/or other serious injuries. The approach would have given extra scrutiny to the risk for mines that encompassed 74% of the fatalities during 2007-2010.

Jan 1, 2012

By E. T. Balazs

Share of developing countries in world bauxite resources mining and processing. Technical assistance of the United Nations Industrial Development Organization to the developing world in the field of bauxite evaluation and processing. Review of selected projects of bauxite research and development aimed at creating indigenous capabilities in developing countries: "Assistance to the bauxite aluminium industry of the People's Republic of China". Project activities. UN inputs. Achievements. Follow-up. "Upgrading the scientific and technological capabilities of the Jamaica Bauxite Institute". Project activities. UN inputs. Achievements. Expected follow-up. Assistance to the establishment of an "Aluminium research, development and design centre" in India. Project activities. UN inputs. Achievements. Follow-up. "Establishment of an aluminium institute for research and development in Titograd, Yugoslavia". Project activities. UN inputs. Achievements expected. Second UNIDO group training on bauxite evaluation and processing to alumina October - November 1983 in Budapest, Hungary. Programme and coverage. Show of movie picture on organization and execution (15 minutes). Significance of UNIDO's assistance to the developing world in bauxite research and development. References.

Jan 1, 1984