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By Sandeep Upadhya, Marc Morgan, Baljinder Bassi, James Fletcher, Mike Deevy, Nishant Nayan

"In order to protect public safety in the event of a deliberate fire attack, underground rail authorities are increasingly considering the need to design for arson-initiated fire scenarios. Where typical design fires for modern rolling stock mean a peak fire size is reached after 12 minutes, an arson-initiated fire reaches its peak within 2-3 minutes. We present the innovations required to successfully incorporate this requirement on a recent design-build project. In stations 3D modelling is used to optimise smoke reservoir designs, smoke chimneys, station boxes and tunnel geometry to allow coordination with structural requirements. In tunnels, novel coupling of one dimensional network modelling and 3D Computational Fluid Dynamics (CFD) is used to improve assessment of complex fire scenarios. Finally, the impact on tunnel structures is assessed through comparison with standard time-temperature curves and risk of explosive spalling. INTRODUCTION An increasing regulatory environment and the appreciable influence that terrorist incidents have had on public safety policy have motivated the need to protect against large arson fires, especially in civil structures and public transport systems. With a greater reliance of a growing urban population on underground subway systems, design of such infrastructure is continually being reassessed and developed worldwide. Underground rail authorities are paying increased consideration to the design of fires - with properties beyond the upper regions of growth and intensity - amongst arson fire studies. Use of fire hardened materials on modern rolling stock means fires caused accidentally can be expected to develop relative slowly. However, recent experiments involving large initiating fires (as would result from an arson attack) have shown rapid fire growth rates and flashover leading to greater maximum heat release rates, Hadjisophocleous (2012), White (2010), and Lönnermark, et al. (2015). This paper describes the challenges and innovations required to complete a detailed design to control smoke from such aggressive super-fast growing fires. Computational modelling is used to demonstrate the required smoke control design by configuring the mechanical exhaust system combined with careful coordination with the architectural and structural design. The design objectives are to provide tenable egress paths in accordance with NFPA 130 (2014) and fire-fighting access. Finally, analysis of the design fire is used to inform the tunnel lining design, reducing the risk of explosive spalling, protecting the asset in the event of a severe fire."

Jan 1, 2016

By Ernest L. Bradley

A positive pressure ventilation system, augmented by a dewatering well curtain and underground longhole drilling, provides effective ventilation and radon control at EXXON Minerals Company's Highland Underground Mine in the Southern Powder River Basin of Wyoming. Testing different types of bulkheads, sealants, and bleeder systems has led to improvements in the basic ventilation system. Continued testing of new or different materials and equipment is expected to lead to further improvement in the ventilation program. Effective training of both miners and supervisors is essential to maintaining and improving ventilation techniques. This paper addresses the ongoing ventilation program and experience to date at the Highland Uranium Mine.

Jan 1, 1979

By Ashis Bhattacherjee, Bijay Mihir Kunar

A literature review on quantitative analysis of mine safety studies revealed that investigators use a wide range of statistical techniques for the analysis of mine injury data. Researchers have addressed the various issues of accident causation and prevention through analysis of mine injury data collected from mines. These studies are generally based on historical accident/injury data without considering the injured person/population at risk. In this paper, a public health approach, based on scientific methods of epidemiology, is presented to address mine safety issues. Epidemiology is the scientific study of disease and injury patterns among populations in time and space. Originally, epidemiology was concerned with epidemics of communicable diseases. Then it was extended to non-communicable diseases. Safety researchers found that epidemiologic methods are the best tools for injury research, because the occurrences of injury and the occurrences of disease are quite similar. As a result, some researchers started applying this concept to injury research. This paper presents some of the techniques used in epidemiologic studies and illustrates the application of a case-control study design to evaluate the role of some risk factors associated with injuries in underground coal mines. In this study, the injured persons were identified and, simultaneously, interviews were conducted to find the significant risk factors responsible for occupational injuries in coal mines.

Jan 1, 2011

By Mark A. Koestel

Cobalt-sulfide mineralization can he found in potentially economic quantities where permeable, basal Cambrian formations "pinchout" against Precambrian pal eotopographi c highs. These environments are common around the Saint Francois Mountains of southeastern Missouri and they share many similarities with the geologic environments of Zambia and Zaire in South Africa. Exploration for this type of deposit involves test drilling targets identified by trend analysis from past drilling, geophysics, geochemistry and a comprehensisve study of regional geology and isopach maps. Innovative ideas, new exploration concepts and insoluble residue geochemical methods may provide the necessary "edge" needed to complement basic geologic understanding leading to ore discovery.

Jan 1, 1987

By Charles G. Frush

The function of the mine surveyor is to (a) provide a network of points of accurately known position, covering the entire mine property, (b) obtain the required data for the preparation of useful maps and sections! (c) provide position and directional control for the guidance of the operations, (d) measure the progress of the work, (e) measure the movement of rock masses, and (f) make miscellaneous surveys as needed. Mining properties range from the very small to the extremely large, and from those which involve only surface operations to those involving extensive underground workings. Active mines undergo constant change, necessitating continual updating of the surveys. The differences in the character of the deposits, the scale of mining and the mining methods result in large differences in the surveyor's activities and techniques, but many of the problems involved are common to most mines. The surface work of the mine surveyor is very similar to that, of the plane surveyor in that control points are established by triangulation, trilateration and traversing. Detail is taken by direct measurement, by stadia and by aerial photography. The equipment used, the techniques and the methods of processing the resulting data are likewise very similar. However, the underground work is quite different : A. The lines of sight frequently must be carried through constricted openings, often involving short lines of sight and awkward setups. B. The lighting often is poor, requiring illumination of the backsights and foresights, and the crosshairs. C. The ambient conditions often are difficult, involving falling water, high tem- peratures, poor visibi 'kv and heavy traffic through the area being suneyed. D. The surrounding rock map be unstable, resulting in movement or loss of the surveying stations, as well as hazard to the surveyors. E. The points to be measured often are difficult or impossible to reach. F. Steep vertical sights often are necessary, requiring the use of special equipment. G. Many working levels commonly are involved, requiring the transfer of position and orientation to each with a high level of precision. This section therefore will concentrate on surveying problems peculiar to the mine surveyor, chiefly underground work. 22.1-THE MINE COORDINATE SYSTEM A system of coordinates is essential for all permanent mining operations It is very desirable that all mining operations in a ,given area b~ tied into the same system, as this minimizes problems of boundaries and connections Whenever possible this system should be tied into and made part of the state or regional grid system. It is desirable to orient the coordinate grid on a true-north line and to position the origin of the coordinates so that all of the work will be in the "northeast" quadrant, making the north and east coordinates always positive. This can be done by subtracting suitable constant values from the north and east coordinates of the regional system The residual values are of more convenient magnitude and can be used as the local mine coordinates. If the long axis of the mineralization is not generally north-south or east-west.

Jan 1, 1973

By P. E. Nielsen, T. L. Loga, B. B. Mauko

A numerical model is presented which simulates the dynamic fracturing process for a circular geometry fracture in a uniform stress medium. The dependence of crack aperture and net pressure in the crack upon various dominant parameters of the fracturing process is discussed. An analysis of a 75% nitrogen foam fracture in a coal seam at 5600 feet (1707 m) is also presented. The analysis is based upon the discussed parametric trends, the job records of treatment parameters, and a Nolte plot of net downhole pressure. It is interpreted that fracturing with water, in pre-foam fracture pump tests, resulted in significant fracture height growth. However, the subsequent foam fracture had reduced height growth due to the high effective viscosity of the foam and due to the higher magnitudes of elastic modulus and stress in the bounding rock strata with respect to the coal.

Jan 1, 1986

By T. W. Martin

The use of conveyors in large, open pit mines and their drawbacks are discussed. Technological developments such as long distance conveyors capable of handling large rocks are explored. The development and testing by the Bureau of Mines of a prototype crib and cable conveyor for handling large rocks are discussed, and possible modifications of the concept for a production model are examined.

Jan 1, 1984

By Sidney A. Suhler

The persistent requirement for methods and equipment capable of detecting hazardous anomalies in advance of underground mining has led to the development by the U.S. Bureau of Mines of a directional radar probe. The probe operates from boreholes drilled from the surface into the underground region to be mined. The engineering model radar was completed in early 1982 and field demonstration tests were performed in May of that year at a selected coal mine. Preliminary in-situ electromagnetic tests were performed at several candidate coal mines to evaluate the radio-frequency characteristics of the coal. A coal mine in New Mexico was selected on the basis of low EM propagation losses in the coal and the presence of an extensive coal seam displacing fault as a radar target. The borehole radar was operated in two vertical boreholes which intersected the coal seam at approximately 25 and 40 feet from the fault interface. Radar reflections from the coal/ rock interface were detected in both tests. Underground tests in a horizontal borehole in the coal were less successful because of interfering reflections. Additional borehole-to-borehole tests were performed with a separate ground penetrating electromagnetic system to obtain radar range calibration data. The coal was found to be bounded by very lossy roof and floor sandstone and shale while propagation through the coal seam was obtained at distances up to 175 feet between test boreholes. Coal seam continuity was indicated by the hole-to-hole experiments through a section of the seam previously thought to be completely cut off by the fault.

Jan 1, 1983

By W. C. Foshee

The large volume of water used in coal preparation plants makes water recycling a necessity. Economical cleaning of dirty water usually requires flocculation with an efficient organic polyelectrolyte. This paper discusses identification of optimum flocculant systems. Supporting laboratory data with on-site tests and full scale field trials supplies information necessary for matching the polymer to the plant.

Jan 1, 1979

By Wilfred Walker

A working hypothesis is presented herein mineral belts are split as all world oceans opened. Rather than plate tectonics, expansion is favored as the most recent expression of the sequence of convecting systems in the Earth's mantle. Throughout the geological record this sequence has produced similar mobile belts. This similarity lends itself to both stratigraphic classification and the theme of mineralization in mobile belts demonstrated by Y. A. Bilibin. Crustal evolution should, therefore, serve as an important guide in understanding Pacific mineral belts.

Jan 1, 1982

NIOSH is conducting research to reduce the silica dust exposure of workers at surface coal mines. One goal of this research is to evaluate the relationship between drilling parameters, rock strata and silica dust generation. This study involved measuring blast hole emission dust from a rotary drill rig which required sampling high concentration dust (>400 mg/m3) for silica content in a high velocity airstream. To measure dust initially, traditional sampling methods using personal sampling instruments were attempted in and around the shroud area of the drill with no success. Variations in the dust cloud concentrations under the shroud, the condition of the shroud and its orientation over the hole, and ambient air conditions prevented consistent and accurate dust measurements from being obtained. Amore consistent dust cloud is necessary for accurate measurements. An area of the drill’s dust collector system that consistently draws the emitted airborne dust from the hole is the collector tube. This tube connects the drill collector’s vacuum and dust filtration system to the shroud area. Assuming the collector system is working as designed, sampling from the collector tube would enable more consistent and accurate samples to be taken. However, current personal samplers are unable to sample in the concentrations and velocities experienced in the collector tube, so another method had to be devised. To achieve the desired results, an in-stack cascade cyclone was used. Preliminary field testing shows positive results.

Jan 1, 2003

By S. Chander

The mechanism of oxidation of sulfur in pyrite is a function of the rate and driving force for oxidation. New evidence is presented in this article to show that at moderate potentials, a sulfur-rich hydrophobic layer is formed. Under ordinary conditions, the sulfur layer is covered with a layer of iron oxides, hydroxides, sulfate or oxy-sulfide ions. Under these conditions, pyrite is hydrophilic. In the presence of iron-chelating agents or iron sequestering ions, iron layer might not form. Under these conditions, sulfur-layer is exposed and pyritic might become hydrophobic. Stronger oxidizing conditions decompose the sulfur-layer, thereby making the surface hydrophilic.

Jan 1, 1992

By Anne Kathrine Kalager

"Stretching from Norway’s capital, Oslo, to the city of Ski, a new railway line is under construction with a 20 km long hard rock tunnel. This is a major project with high demands regarding quality, cost and schedule. In addition, restrictions concerning locations close to sensitive urban infrastructure require execution with the highest level of precision and expertise. The new double track railway line forms an important part of the intercity rail development southwards from the capital and includes the longest railway tunnel to date in the Nordic countries. With its novel methods and solutions, this project offers a model for future railway project developments in the region. This paper provides general pertinent details and facts relating to this current railway project and includes a description of the project with information relating to concept and design of the tunnels, geological conditions, particular challenges, selected tunneling techniques and contracting strategies. THE FOLLO LINE PROJECT The Follo Line is a new 22 km long double track railway line under construction between Oslo Central Station and the city of Ski. The project is divided into four subprojects, as shown in figure 1. The main part of the project consists of a 20 km long hard-rock tunnel, which will be the longest railway tunnel in the Nordic countries to date.The Østfold Line is the existing double-track railway line running between Oslo Central Station and Ski serving 12 local stations. The new Follo Line will offer a direct service, without stops, between Oslo Central Station and Ski and reduce the travel time from 22 minutes to 11 minutes. After completion of the Follo Line, these two railway lines will, in combination, more than double the capacity for train transport in the region south-east of Oslo."

Jan 1, 2016

By Harry R. Asche, Manfred K. Lechner

The Cross City Tunnel comprises 2km of a new underground traffic route in Sydney, Australia. The route is very complex, involving some six separate tunnels and three underground Y-junctions. For almost 200m the six tunnels run parallel at different level sunder William Street, Sydney. Almost all of the route runs adjacent to the City Business District of Sydney and adjacent to or below many major buildings and services. The planning and design of this project is described. The geometric arrangement is achieved with a strong dependence on 3D road design packages. Road alignment constraints include land acquisition and proximity to existing tunnels and basements as well as maintaining separation from the other tunnels in the scheme. Geotechnical and hydrogeological studies are described. Findings discussed include the high horizontal stress field in the Sydney area and investigation of incised palaeochannels on the route. Methods of design for the tunnels and Y-junctions are described, as well as methods of settlement prediction for the buildings and services. The latter includes the settlement assessment for more than 200 buildings, many in excess of 20 storeys, as well as services including all of the city railway lines in Sydney.

Jan 1, 2003

By J. C. C. C. Menezes, R. A. S. Silva, A. V. Colling, I. A. H. Scheneider

"Coagulants rich in ferric sulfate can be obtained from pyrite-containing coal tailings using a biohydrometallurgical process. The aim of this study is to evaluate the relationship between quantity of pyrite and rate of oxidation, with regard to the consequent production of ferric sulfate for potential use as a coagulant for water and wastewater treatment. Leaching experiments were carried out on the laboratory scale on four coal tailings with different concentrations of pyrite. Characterization of the coal tailings was conducted for the following parameters: total sulfur, pyritic sulfur, sulfate sulfur, organic sulfur, and elemental analysis of CHN (carbon, hydrogen, nitrogen). The samples were also subjected to X-ray diffraction analysis to assess their mineral compositions. The leaching experiments were accomplished using a laboratory column constructed as a packed bed reactor with a sprinkling system in a closed circuit. After four weeks of leaching, the liquor was filtered and evaporated to an iron concentration of about 12 percent w/w, which is typical of the ferric sulfate coagulants commercialized in Brazil. IntroductionCoagulants used for the treatment of water and wastewater are predominantly inorganic salts of ferric iron and aluminum. Aluminum salts, including aluminum sulfate and aluminum chloride, and prehydrolyzed metal-ion reagents, such as polyaluminum sulfate (PAS) and polyaluminum chloride (PAC), are the coagulants most widely used for water treatment (Bratby, 1980; Tchobanoglous et al., 2003; Buzin et al., 2014).However, the presence of residual amounts of aluminum in drinking water has been controversially implicated in neurological diseases (Association of California Water Agencies, 2000; Becaria et al., 2006; Campbell, Hamai and Bondy, 2001; Rondeau et al., 2000; Walton, 2006). A possible alternative is to use iron-based coagulants, such as ferric chloride, ferric sulfate or polyferric sulfate, instead of the aluminum salts (Jiang, Graham and Harward, 1996; Jiang and Graham, 1998). Iron-based coagulants are commonly produced by the acid dissolution of iron scraps or iron ore (Tchobanoglous et al., 2003).Recent studies have shown that it is possible to produce ferric sulfate coagulants from the pyrite present in coal tailings through a biohydrometallurgical process (Colling et al., 2011). The main advantage of this process is that it does not require acid addition, which can be favorable in terms of production costs. Acidophilic bacteria, such as Acidithiobacillus ferrooxidans, can increase the rate of pyrite oxidation and dissolution by several times (Kontopoulos, 1998; Brett and Jillian, 2003; Johnson and Hallberg 2003). They can be highly significant in the bioprocessing of coal tailings for the production of ferric coagulants, as their action favors the acidification of the medium and iron leach (Colling et al., 2011)"

Jan 1, 2016

High pressure grinding mills have been successfully introduced in the industry. They offer the possibilities for capacity increase of existing plants and reduction of operating costs. Further metallurgical advantages in gold and copper are possible. The plants in operation are running in different applications and modes of operation. They can be installed in a combination with SAG and ball mills or in a stand-alone mode. In combination with other grinding mills, it has to be investigated how the HPGR can be installed to reach the full efficiency. This paper describes the possibilities to implement high pressure grinding rolls and shows by case studies the potential of savings which could be reached

Jan 1, 1996

By David P. Keller, George Podolsky

Iron oxides are unique in that they are the only significant colored mineral found in a natural state suitable for use as a pigment after being pulverized to pigmentary size. The world production of iron oxide pigments is estimated by the authors to be between 350 and 400 kt. The fact that highly colored natural deposits of iron ore are found throughout the world accounts for its use in prehistoric man's artistic cave paintings. These early artists did not realize that they had established man's first paint test which now has some 20,000 years of exposure. In addition to abundance, iron oxides (about 7% of the earth's crust) have the advantage of low cost, permanency, and are non- toxic. Through the centuries, succeeding civilizations have utilized iron oxides as a major source for decoration and protection when these properties were desired. In the last century the chemical industry has improved on nature by developing a complete range of synthetic iron oxide pigments which surpass the pigments produced from natural iron ores in uniformity, color quality, and chemical purity. In the United States, the combined production of natural and synthetic iron oxides produced sales of over $97 million in 1980 (Spimad, Jr., 1980), increasing to $138 million by 1990 (Templeton, 1990) NOMENCLATURE With the increasing importance of the synthetic iron oxides it is necessary to make a distinction between the natural or mineral pigments and the synthetic pigments. Natural pigments are those products that are derived from selected ores and should not be confused with iron ores mined for steel production. Iron ores that are mined for steel must be capable of being mined and reduced to iron on a competitive commercial basis. These ores are selected on the basis of iron content and processing economics. It is therefore unusual when iron ores for steel production are suitable for use as mineral pigments. Natural pigment ore sources are selected for their special physical-chemical properties and are able to command a premium price over iron ores used for steel manufacturing. Synthetic pigments, and in this instance iron oxides, are those pigments produced from basic chemicals. Through chemical synthesis pigmentary particles are produced as opposed to the use of comminution, the major procedure common to all natural iron oxide pigments.

Jan 1, 1994

By M. Z. Rashad

The intersections of numerous joint sets at the surface of tunneling region of Abu-Tartour-Project in Egypt create blocks with irregular shape and size in the rock mass. Most of these blocks are not able to move into the free space of the tunnel. Few key blocks are in a position to move and as soon as they begin so, some restrained blocks will be liberated. The aim of this work is to find the (removable) key blocks for walls, floor, roof and corners of a portion of the tunnel under jointed surface rocks; and then determine the best tunnel direction.

Jan 1, 1991

The mining industry is an important economical factor in Vietnam. Mining is presently being conducted at about 60 locations and at over 1000 mines. Petroleum extraction and coal mining are the most important parts of industry though metals such as zinc, tin, chromites, iron are also extracted. Last year the sector produced 20 million tons of crude oil, 26 million tons of coal and 500,000 tons of apatite. In particular, Vietnam is one of the world?s largest producers of anthracite, and it is one of the top producers of ilmenite and zircon in the Asia-Pacific region. The government intends to increase the mining production on all levels, however, at present one can observe adverse impacts of the mining activities on the natural environment such as insufficient waste dump rehabilitation, occurrence of acid mine drainage, mining subsidence and emissions as well as lack of appropriate water treatment facilities. This paper describes the current mining situation, future perspectives, the major environmental challenges of the country and approaches to solve these problems. Particular emphasis will be given to the research project ?RAME ? Research Association on Mining and Environment in Vietnam?, a venture carried out by universities, research centres and industry. This project is worked out in collaboration with the national Vietnamese coal and industrial minerals company VINACOMIN.

Jan 1, 2006

A coal mine located in southern West Virginia recently set a world record for daily low-seam coal production using a Cat automated longwall plow system. In a 24-hour period on April 10 and 11, 2014, the Pinnacle Mine longwall produced 32,411 t (35,724 st) from the Virginia Pocahontas No. 3 Seam, in a seam height of just 1.42 m (56 in.) along the 298-m (980-ft) longwall face. The Pinnacle Mine, located near the town of Pineville and owned by Cliffs Natural Resources Inc., an international mining and resource company, operates a Cat Gleithobel GH1600 Longwall Plow System. A previous record was set by this system at Pinnacle in August, 2012 when 29,423 t (32,430 st) were mined in a 24-hour period. The record was set by the same system, mining its second panel after a comprehensive rebuild was performed by Carter Machinery, the Cat Dealer in that area. The rebuild encompassed a complete rebuild of the headgate and tailgate armored face conveyor (AFC) drive, the headgate and tailgate special AFC pans, the stageloader drives and return end, the complete crusher and all gearboxes for the plow, AFC and stageloader. Carter acquired the rights to sales and aftermarket support associated with the former Bucyrus mining products, both surface and underground, in 2013. ?Supporting and rebuilding a longwall plow system was a new experience for the Carter service team,? said Chris Curfman, president of Caterpillar Global Mining Sales and Support Division. ?However, given the record production results attained by the rebuilt system at Pinnacle, it?s obvious that they are up to the challenge of supporting the underground product lines at the same high standards and quality level that they have been delivering for many years on the traditional Cat surface mining products.? Tom Bluth, president of Caterpillar Global Mining Products Division, said, ?Caterpillar congratulates the Pinnacle team for this great achievement. Without their efforts and dedication this record would not have been possible. To safely deliver that kind of output from such a thin seam is remarkable. We have been privileged to work alongside their team to demonstrate the capabilities of Cat longwall mining technology. ?