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By W Ludlow, C Harrington

This paper presents an overview of the design and construction challenges to implement capping systems on Tailings Storage Facility’s (TSF) based on recent projects in Australia. Key aspects discussed include the cover design and barrier system to encapsulate the tailings, designing for a service life of 1,000 years, water management considerations. construction on tailings, vegetation selection and agronomy of the available capping soils plus the Health, Safety and Enivornmental challenges faced in working on tailings. Lessons learned from experience in capping TSFs are also presented. CITATION:Ludlow, W and Harrington, C, 2018. Experience with Capping of Tailings Storage Facilities for Decommissioning Projects in Australia, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 157–165 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By Ole Bernt Lile

The well-known method of C. Schlumberger, Mise a la masse, has become a popular method again in ore exploration in Norway after many years of dominance by EM methods. The principle of the method is to place a current electrode within a conducting ore body and remove the other electrode to a great distance. (Figure 1). Often it is convenient to place a return electrode on each side of the area explored. The method is best suited for ores that have a conductivity contrast, relative to the host rock, of several orders of magnitude. The potential drop within the ore itself may then be neglected and the ore contact against the rock may be regarded as an equipotential surface. One may say that the ore body is electrically charged. Therefore, in Norway the method is now most often called the Charged Potential Method (abbreviated CP). The most usual way to present data obtained by CP, is to draw equipotential lines based on potential values measured in profiles on the surface. Such a potential map gives an immediate picture of the outcrop of the ore and also indicates disturbing conductors in the neighborhood. It may also be useful to look at the potential profile and its horizontal gradient along the strike axis of the potential map. These profiles may give information about the strike length of the conductor. Figure 2 shows the theoretical profiles of potential and gradient along the axis of the potential picture on the surface over a charged line plunging 15 degrees. It may be seen that the maximum of the gradient curve clearly indicates the lower end of the conductor. Figure 3 shows the corresponding pro- files over a charged line plunging 45 degrees. In this case, it is not possible to see an indication on the curve of the lower end. Only curve fitting could help interpretation in this case.

Jan 1, 1975

By F. G. Schora

The Institute of Gas Technology (IGT), under sponsorship of the U. S. Department of the Interior, Office of Coal Research (OCR), and the American Gas Association (A. G. A. ), has been undertaking the development of one of several processes to convert coal to high-Btu gas as a means of supplementing natural gas supplies. It is anticipated that there will be a significant need for such gas in the foreseeable future in order to meet the ever increasing demands for this preferred fuel form. HISTORY The development of the HYGAS® Process is based on various studies conducted at IGT starting back as far as 1945. Initial work was directed toward production of synthesis gas with subsequent catalytic methanation. By 1964 the concept of the direct hydrogenation of coal to produce methane noncatalytically was well-founded and the chemistry was reasonably well established. Work up until this point in time was financed by the American Gas Association. In 1964 the U. S. Department of the Interior, Office of Coal Research joined with A. G. A. to support the program. The objective at that time was to develop the necessary know-how to enable the design of a pilot plant, a necessary step in the ultimate commercialization of the process. Work for the next three years (1964-1967) emphasized investigation of fluidized-bed technology in the hydrogasification step, where moving-bed technology had been previously employed, as well as identification of commercially available catalysts acceptable for catalytic methanation of the CO and hydrogen in the hydrogasifier effluent under operating conditions in the system. By 1967, the preliminary design of a 3 ton/hr pilot plant had been finalized, and IGT received authorization from OCR to proceed with the detailed design and construction of that facility. The pilot plant was designed to study the following problems:

Jan 1, 1972

By Jesse H. Auvil

In January of 1966, during the annual session of Georgia's General Assembly, Representative Paul E. Nessmith of Statesboro, Georgia, walked into my office and asked me what I thought of the advisability and feasibility of a law which would require the mining operators to reclaim their mined out lands. My answer to him was, as a one time mine superintendent and operator, that I probably would not think very highly of the added cost which reclamation would impose on the operation; but that since assuming the job of Chief Geologist and Assistant Director of the Georgia Department of Mines, Mining and Geology, and in retrospect, I could recommend it very highly, particularly in view of the increased pressure being applied by the Federal government along these lines. I stated then and still emphatically state that this sort of administration should be done on the State level rather than the Federal level. He asked me if I would conduct him on a tour through some of the mining country in which I had worked and to this I readily agreed. The result of this trip was that he was adversely impressed by the devastation which the mining operations had wreaked on that area of middle Georgia along the fall line known as the kaolin belt. Very little except talk was done for the remainder of 1966.

Jan 1, 1970

By Wolfgang R. Wawersik, Charles M. Stone

INTRODUCTION Hydraulic fracturing was applied in horizontal drill- holes in the Salado salt formation near Carlsbad, New Mexico. Tests were performed approximately 650 m be- low surface to validate the design of a Waste Isolation Pilot Plant (WIPP) for the disposal of radioactive waste from defense activities of the United States. Hydraulic fracturing was performed primarily to determine whether the virgin in situ stress state at the WIPP site is isotropic and whether the magnitude of the virgin in situ stresses corresponds to the weight of the overburden. Beyond these limited objectives, however, measurements are now being reviewed to evaluate the usefulness of hydraulic fracturing in salt formations in general. Such measurements are desirable to determine stresses induced by mining and to monitor time-dependent stress changes around underground excavations in salt masses. Hydraulic fracturing was chosen because it is the only technique that can be readily applied in virgin ground far from existing mine openings. The method also appeared to yield directly the magnitude of the least compressive principal stress, regardless of the mechanical properties of the rock mass. A knowledge of the least principal compression was deemed sufficient to establish the isotropic character of the virgin in situ stress field under two conditions: (1) the Salado formation was mechanically isotropic, i.e., the fracture toughness did not vary normal and parallel to bedding so as to permit preferred fracture paths, and (2) pressure measurements were combined with determinations of the orientations of hydraulic fractures and, more generally, with observations of the characteristic hydraulic fracture patterns. The latter was possible by locating the drillholes for hydraulic fracturing along the axes of drifts that were mined several months later. The success of general stress measurements by hy- draulic fracturing of salt subjected to anisotropic stress conditions was and remains less certain. While the smallest in situ compressive stresses should still be equal to instantaneous shut-in pressures, there may not exist any unique relationships between the greatest and intermediate in situ principal stresses on one hand and the primary breakdown and fracture reopening pressures on the other. This problem would be a consequence of stress relaxation due to salt creep around any drillhole in which hydraulic fracturing tests are conducted. Moreover, lab- oratory measurements suggest that creep and stress relaxation could be so rapid that it might not be possible to interpret the measurements for anisotropic stress conditions even if hydraulic fracturing were performed as soon after drilling as possible. The primary objectives of the stress measurements in the WIPP were met by combining hydraulic fracturing tests with finite element analyses of the effects of salt creep, observations of hydraulically induced fracture pat- terns, and laboratory hydraulic fracturing tests on oriented core. In situ hydraulic fracturing tests in long drillholes were preceded by several trial tests to establish the best test methods and to demonstrate that salt could be fractured. The resolution of anisotropic stresses and special problems, e.g., in the identification of instantaneous shut-in pressures, are currently being addressed in hydraulic fracturing tests in a mine pillar, in tests following different delays between drilling and fracturing, and in tests with different frac fluids. This paper will review the main results of the analyses above and of one group of hydraulic fracturing tests at different distances from existing excavations. The paper will conclude with a brief description of the geometry of the hydraulically induced fracture patterns. Because of space limitations, it will be assumed that the reader is familiar with hydraulic fracturing or will first consult other sources (e.g., Cleary, 1980; Gronseth and Detournay, 1979; Zoback and Haimson, 1983; Nemat-Nasser et al., 1983; Kim et al., 1984)

Jan 1, 1986

By Y. L. Mehta

The working experience of the Zinc Smelter, Debari, Udaipur with process modifications and iron control practices is described in detail in this paper. Most of the modifications were made at different times as part of capacity enhancement campaigns that led to distinct advantages, thereby increasing both zinc production and recoveries. This smelter came into existence in 1968 with a humble beginning of producing 18,000 metric tonnes (MT) of zinc per annum, using the conventional batch hydrometallurgical roast-leach-electrowinning technology. Zinc production capacity was increased stepwise to 45,000 MT, 49,000 MT and 59,000 MT, by making suitable process modifications and adopting new technologies, particularly in the leaching section. During these modifications, the process of iron separation as Moore cake was also changed to jarosite cake production. At present, jarosite is being disposed in a secured landfill at the Zinc Smelter, Debari (ZSD) and as Jarofix at the Chanderiya Lead Zinc Smelter (CLZS). As a result of subsequent in-house performance improvement and debottlenecking campaigns, this smelter could achieve further increases in production. Zinc production for the financial year 2005-06 was 81,000 MT.

Jan 1, 2006

By W. A. Jones

Purpose of Paper Geophysics is a highly developed science which has found a wide use in industry. Perhaps the most spectacular application has been in the field of oil exploration. It has been estimated that, up to the end of 1939, geophysics was responsible for the discovery of five billion barrels of oil. In 1944, the sum o $40,000,000 was expended for geophysical work in the search for new oil deposits. Although the metal mining industry has so far made comparatively little use of the science, it is becoming increasingly common for the exploration engineer or geologist to be required to co-operate with the geophysicist. Many papers dealing with applied geophysics have been published but in most of them advanced training in physics and mathematics on the part of the reader has been assumed. It is difficult for the average engineer to obtain a ready understanding of the equipment, field procedure, and scope and limitations of the science from the literature. The present paper attempts to describe briefly and in simple terms the principles underlying magnetic, self-potential, and electrical resistivity methods and their application to a field problem. Introduction Geophysics is concerned with the study of gravity, magnetism, natural earth currents, earthquakes, vulcanism, and many other natural phenomena. The methods, originally devised for the measurement, for scientific purposes, of the forces associated with such phenomena have been adapted to the search for buried deposits of economic value. If the body sought has large dimensions and distinctive physical properties, geophysical measurements may reveal associated, and in some cases quite characteristic, anomalous features. However, in many instances the mass cannot be indicated directly but has a common association with geological features which can be defined by physical measurements. Although such surveys cannot specifically identify oil, metalliferous minerals, or other commercially valuable substances, it is possible to delineate anomalous sub-surface physical features which, with the help of geological information, can be assessed as possible or probable indications of the body or structure sought. The nature and extent of the material causing an anomaly, and its economic importance, can only be determined by further exploration, such as drilling.

Jan 1, 1947

By D. C. Yates, G. V. Jolliffe

In the five coalfields of Staffordshire, there have been some 43 incidents of spontaneous fires and heatings which have required special attention in the past ten years. This total excludes incidents in the Thick Coal Seam of South Staffordshire, which was worked until 1967, and which was subject to an almost continuous series of heatings. The incidents have been classified to show the sites of occurrence, the contributory factors which may have caused them and the treatments applied to them. The remedial techniques, as practised in Staffordshire, are dealt with in detail, with particular reference to standard methods of stopping-off. Precautionary measures taken are described, including a "liability to spontaneous combustion" classification of all seams, and the setting up of an emergency organization with emergency stocks of materials and equipment. The paper is concluded by a few words on the organization and control at the time of an incident.

May 23, 1905

By G. A. Gunderson

Since our time is very limited, I would like to relate to you as best as I can a few important areas that I think may be helpful. 1.) The Real Difference between Dense Phase and Dilute Phase Pneumatic Conveying: Within the many variations of so called Dense Phase conveying, it is often difficult to determine to what degree a system is Dense Phase or if, in fact, it is a Dense Phase system at all. A system that appears and is generally known to be Dense Phase can under certain operating conditions perform as a Dilute Phase system. If, for instance, a high pressure system, which is generally a Dense Phase system, operates at 60 PSIG, say 4 atmospheres, utilizes enough air volume, the conveying velocity will easily exceed the normal design velocity of a typical Dilute Phase system. Now, on the other hand, a low pressure system which we will term a Dilute Phase system, operating at 15 PSIG; say 1 atmosphere, can convey a given product at well below the saltation velocity, like a Dense Phase system.

Jan 1, 1977

By Edward B. Cook

INTRODUCTION. THE installation of the Gayley Dry-Air process appealed specially to the management of the Warwick Iron & Steel Co., for the. reason that for fifteen years records had been kept at the works of the company, showing the amount of water entering the furnace in the form of aqueous vapor, and careful observations had been made of its effect upon the working of the furnace. Some years had proved much worse in their effect than others, on account, not only of excessive moisture, but also of great variation in the moisture from day to day, and sometimes within a few hours. It had been found impossible to. make a satisfactory percentage of high-silicon foundry-iron in summer, even on high fuel; and for some years the endeavor had been made so to arrange the sales that, during July and August, only a small percentage of the iron produced would be required to carry more than 2 per cent. of silicon. Our larger furnace, running on basic iron, year after year, produced in February a tonnage 20 per cent. higher than in August, on a much lower fuel-consumption, while, at the same time, the summer months were marked by ? messes," tuyeres closed by slips, and other irregularities, constituting serious additional business losses. It will be easily understood, therefore, that the records made at the Isabella furnace after the installation of the dry blast in 1904 possessed special interest, and were closely watched by us. On the basis of our own experience, we argued that if the moisture could be kept low, and also uniform, the cost of installation would be more than justified. The subject was brought before our Board of Directors in the fall of 1905; and in the spring of 1906 it was decided to install a plant of sufficient capacity to treat 70,000 cu. ft. of air per min., an amount

Nov 1, 1908

By Vincent Jue

In December 2009, the Italian High Speed Rail Network AV began running over the full 1000 km system length from Turin, at the foothills of the Alps to Salerno, on the seacoast south of the volcano Mt. Vesuvius. It runs through Alpine rivers, highly seismic active zones, mountains, river plains, and through some of the most densely populated areas in Europe as well as some of its most expensive real estate. The Italian High Speed Network?s technical/economic constraints and its regulatory/socio-environmental concerns well may mirror similar obstacles set to confront the nascent California High Speed Rail Program. The two types of constraints must be dealt with together to reach the best construction solution. It is estimated that more than 20% of Italian High Speed Rail Network costs were spent on ground engineering including over 150 km of tunnels, 200 km of viaducts and bridges and 650 km of embankments and trenches. However, it also is estimated that 25% of costs were spent on social and environmental integration of the new rail lines including over 6 square miles of green offsets, 160 km of anti-noise walls, and 300 agreements for socio-environmental work. This paper will look at four examples of innovative ground engineering solutions, each with its own intricate set of constraints: ? Foundation system for viaducts across the ?Po? and ?Ticino? rivers. ? Soil consolidation under railway embankments ? Requirement of short tunnels for physical and environmental reasons ? Construction of railway stations in a confined right of way

Jan 1, 2010

By Luis R. Fonseca, C. Raimat, C. Wendeler, A. Sanz

"Rockfall barriers are widely known as proven efficiency element to protect infrastructure by catching the rock blocks in the falling direction and absorbing the energy generated by them.It’s common in the project design phase and during installation, fix rockfall barriers for catch a high percentage of the falling blocks and in many cases consider as valid the solution when the barrier can capture all of them. However, in many cases it’s possible to consider the use of these protections, simply to guarantee a secure shed for the traffic and intercept simply the blocks that theoretically hit the road surface.The results of the high-energy rockfall protection barriers type GBE which protect GC-200 road in Las Palmas de Gran Canaria are shown in this paper.The topographic data should be especially detailed observed and even more if you want to apply the technique of ""shadow zone"" with a flexible gallery system. It should be drawn from detailed topographic maps and drawings (photogrammetric restitution) to the scales 1/1000, 1/500, or 1/200; and it is important not to ignore the presence of vertical cuts, tracks, small slopes that modify the trajectories (trampoline effect, hard points that favor the rebounds) and which are not always presented in the drawings.The ""shadow zone"" is defined as the protected area, located at a lower elevation to the line created by the rockfall barrier to except of trajectories of rocks and free from the influence of the deflection of the system under the maximum energy level for which it was designed (MEL)."

Jan 1, 2015

By D. V. Hughes, J. R. Nyberg

"Since 1985, a comprehensive automation system has been installed at the Outokumpu Oy Zinc Plant, Kokkola, Finland. In leaching and solution purification special sample handling equipment, on-line analyzers and instruments, and a computer-based control system with duplicated supervisory stations have been installed. The system has enabled closer control of the process and more efficient use of labor. Since its installation recovery of zinc has improved, and use of zinc dust, steam, and water have decreased. The system has performed reliably. It includes optimizing programs and process study tools, which facilitate improving process performance. An expert system has been built-up to prompt process personnel to take appropriate action on the basis of process data. In electrolysis a similar system, based on extensive monitoring of the process and of production of zinc cathodes, is used to maximize- current efficiency by maintaining optimum conditions in the process. It is planned that in the future the control systems will be integrated and extended to cover the roasting plant and effluent control.IntroductionThe Zinc PlantThe Zinc Plant of Outokumpu Oy Metallurgical Division at Kokkola, on the West Coast of Finland, has grown from a 90,000 t/a plant founded in 1969 to become, with its present capacity of 170,000 t/a, one of the world's ten largest zinc plants. Especially since the completion in 1988 of a thorough modernization programme, it is also among the world's most modern.The Kokkola plant takes its raw materials from Outokumpu's own mines, Vihanti and Pyhasalmi in Finland, and Tara in Ireland, and from outside sources. Concentrates are roasted in two Lurgi fluid-bed furnaces, and the calcine is leached and iron removed by the Conversion process. Following this copper, cobalt, and cadmium are removed, and zinc is refined by electrowinning. The leaching and purification, and the cell-house are automated under computer-based control, and anode and cathode handling in the cell-house are mechanized and fully automatic."

Jan 1, 1989

By Patrik Ericsson

During the 90?s Atlas Copco and LKAB developed a pioneering fully automatic long hole production drilling system based on the Atlas Copco Simba W469 drill rigs. These drill rigs have since then drilled about 8.000.000 drill meters at the LKAB Kiruna and Malmberget mines. In 2005 LKAB ordered three new Atlas Copco Simba W6 C, to complement Simba W469s still in operation. These new Simbas are based on the latest generation computerized drilling technology have proven to meet the expectations of LKAB and now form a base for future automation in Kiruna and Malmberget mines. This paper will present experiences from the introduction of Simba W6 C in LKAB Kiruna and Malmberget mines. The paper will also elaborate on the latest developments in remote access and remote control technology making it a common automation option available for all computerized Atlas Copco drill rigs.

May 1, 2007

By James J. Bean

Although determining and controlling specific gravity of operating medium in a heavy-media plant manually presents no problem, there are advantages to automatic recording and control. The two installations discussed employ the usual method of measurement. Pneumatic control with band control and reset features is used to regulate dilution water and hence specific gravity. Difficulties have been mechanical in nature and associated with obtaining a proper I sample and maintaining tight air connections in bubble-tube piping:

Jan 1, 1950

By Karl Gunnar Holter, Frank Clement

"INTRODUCTION Typically waterproofing of conventionally excavated tunnels has been done by installing pre-fabricated sheet membranes between the primary temporary support lining and the secondary permanent inner lining. The membrane acts as a separation or sliding layer between the linings, which is often desirable. The geotextile installed behind the sheet membrane provides the required drainage and protection of the system. The design of the tunnel lining is strongly influenced and limited by the use of waterproofing sheet membranes. Since primary and secondary linings are separated from each other, forming a double-shell lining system. In that case the secondary lining must be designed for all permanent loads, although the sprayed concrete primary lining continues resists ground and water loads for a long time after construction. Significant progress has been made in sprayed concrete technology over the last two decades, with advanced admixtures, as well as the improved application technology using spraying robots. The development of new admixtures like superplasticizers based on poly-carboxylates, alkali free accelerators and silica fume, enables designers to use permanent sprayed concrete linings (SCL) increasingly for long-term service life. When designed and applied correctly, sprayed concrete can be considered as permanent. The use of spray applied membranes has seen increased use over the last decade in some countries, and demonstrated functionality and cost-effectiveness in several situations. This paper describes the use of the sprayed waterproofing membrane MasterSeal 345, an EVA polymer based product, and the practical experiences from several projects. SPRAY APPLIED WATERPROOFING MEMBRANES The sprayed waterproofing membrane is polymer based and has been especially developed for underground structures. The membrane is applied between primary and secondary concrete linings and develops high bond strength on both sides to the concrete (doubled-bonded)."

Jan 1, 2016

By Kent Zehr

Suncor Energy Inc. is an integrated producer and refiner of oil and gas headquartered in Calgary, Alberta. The bulk of revenue comes from the Oil Sands Group (OSG) operating in the McMurray formation of the Athabasca Oil Sands. Located some 25 kilometers north of Fort McMurray, Suncor OSG began life in 1967 as Great Canadian Oil Sands, the first operator to successfully enter commercial production of synthetic crude oils from the area. For most of the last decade, dramatic growth has been the standard mode of operation for Suncor OSG. Production of synthetic crude first reached 100,000 barrels per day in 1997 and less than five years later is averaging in excess of 200,000 barrels per day. Within this dynamic organization, Suncor Extraction is the business unit that processes run-of-mine ore into clean diluted bitumen for Upgrader feedstock. Extraction also delivers and places the barren sand and process affected water into tailings storage in one of several ponds from which water is recycled to support the various processes. For reference purposes, Extraction on a typical day currently receives more than 400,000 metric tons of oilsand ore, which is all processed to water based slurry for separation in one of two extraction plants. Separated tailings are disposed of as a slurry and the cleaned bitumen froth is diluted with naphtha and sent to tankage for storage until required by the Upgrading Unit. As a consequence, on a typical day Suncor Extraction pumps more than 1,000,000 tonnes of aggressive slurry into and out of the two extraction plants.

May 1, 2003

By M. Cousineau, S. Gariepy

"Current business and corporate environments push for improving metal accounting practices in smelters. The ensuing projects commonly proceed along a bottom-up approach. As such, efforts are first put on reviewing the measurement system and then on remedying the identified weaknesses. The focus is thus moved to mass/metal balance only after the measurements upgrade process has been completed. However, practice has shown that assessing the high variances related to suboptimal measurement processes is complicated without the help of statistical data reconciliation. This bottom-up approach leads to a to-do list that can not only exceed available resources but also lack prioritization in view of achieving the targeted end use. This paper describes an upgrade project done differently where all the three dimensions of the metal accounting system: hardware, software, and people were instead involved at the onset. Personnel was thus trained on data reconciliation software at the beginning of the project to make the reconciled mass balance benefits available earlier in the upgrading project. This has pinpointed the most critical measurements where accuracy and reproducibility should be improved. Overall, not only the instrumentation retrofitting process has been streamlined, but the global risk for the whole upgrading project has been significantly lowered.INTRODUCTION Mining companies are pressured to improve their production accounting practices in response to the strengthening of corporate requirements for timely and accurate production reporting (Gaylard, Randolph, & Wortley, 2014). Smelters are not spared from these changes. However, their unique situation in the mining value chain set them as strategic targets for upgrading projects. They usually have a longer lifespan than concentrators thereby offering an extended lifecycle to justify investments. Furthermore, numerous smelters have toll agreements with third parties. Accurate cost and production accounting is, therefore, a vital piece of information to fix acceptable contract conditions. Mining companies are ultimately aiming at a clearer view of the operating performance of each business unit to improve their business decisions in a competitive environment. This sought for increase in visibility through plant performance can only be achieved through an upgrade of the metal accounting system. Figure 1 shows the different components of a state of the art system (Gaylard, Morrison, Randolph, Wortley, & Beck, 2009)."

Jan 1, 2017

By C. H. Zhou

Cryogenic grinding of Printed Circuit Board will bring less pollution, reduce energy costs, smaller particles, regular particle size, efficient process, separation various materials due to different fracture toughness. Systemic studies of recycling discarded Printed Circuit Board (PCB) by low-temperature modification and cryogenic grinding have been made in this paper. Firstly test mechanical property of PCB at different low-temperature, including impact strength, flexural strength, and shear strength. Do experiment on the power consumption of different cooling temperature, The results show that the average power consumption is lower between -30? to -60? and the average power is decrease in evidence at -30?. Use ZKB type double roll shear crusher to crush PCB to 20mm×20mm particle size, in a temperature range of -10 ~ -30? Used R type mill to grind sample to minus 3mm under different working condition, the average power consumption is decrease in evidence from -10 ? to -30 ?, power consumption is the lest at rotational speed is 1180rpm.

Jan 1, 2014

By T. J. Batchler, K. M. Mohamed, D. F. Gearhart, R. K. Zipf

Seals are explosion-resistant structures built in underground coal mines to isolate abandoned mining areas from the active workings. An equivalent single degree of freedom (SDOF) method such as the single-degree-of-freedom blast effects design spreadsheet (SBEDS) developed by the U.S. Army Corps of Engineers can be used to design seals to resist mine explosions. The critical input for the SDOF code is the seal resistance function. The objective for this study is to develop engineering data for design of plain concrete (PC) and reinforced concrete (RC) seals using finite element (FE) models. The FE models can then be used to generate resistance functions for different PC and RC seal designs, which can be used in the SDOF codes. The U.S. National Institute for Occupational Safety and Health (NIOSH) researchers designed and built a test fixture for use in conjunction with NIOSH’s Mine Roof Simulator to apply a four-point bending load on the face of the tested seal. Eight large-scale experiments for each PC and RC seal were conducted. The experimental design considered the effects of the foundation strength, hitching and roof-to-floor convergence. Calibrated FE models for PC and RC seals were developed using ANSYS Ver. 13. With a very limited number of engineering-based assumptions and a single set of data—including Young’s modulus, compressive strength, stress-strain relationships, etc.—the PC and RC seal models successfully calculated the recorded resistance functions and failure patterns for a wide range of boundary conditions. Plug and RC seals were assumed for a 1.83-m- (6-ft-) high entry to demonstrate the application of the calibrated finite element models for calculating the resistance functions of these seals. The resistance function of a particular plug seal case was found to be a bilinear relationship. The resistance function of a particular RC seal without shear reinforcement was found to be a nonlinear relationship.

Jan 1, 2013