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By Benno Ring

"When designing segmental lining at a cross passage, modern solutions try to bear the loads transferred around the opening within the rings by using shear elements in the ring joints. Commonly used shear systems providing coupling are cam & pocket, shear keys, bicones and steel dowels. These solutions have advantages and disadvantages, but most importantly they have limits in their capacity to stabilize the lining at cross passages. With the help of 3D-FE-analyses for an opening of one segmental ring these different solutions are compared taking various ground conditions into account. As a result the capacity of the individual system is determined. Notice is made regarding the applicability of the system as well as the consequences for the design and the verification. INTRODUCTION The design of the lining at a cross passage is among the most difficult tasks when designing TBM-tunnels. At one time the bedding of the lining disappears due to the excavation behind the lining, at another the ring-structure is interrupted when parts of the lining are removed for the opening. The trick is to transfer the loads around the opening into other segments and to areas of the lining which are still supported by the ground. In the rings immediately at the cross passage this creates a distribution of forces within the segments that strongly deviates from that of the regular lining. The design needs to consider the boundary conditions of the respectively chosen solution for stiffening of the opening and its peculiarities in the modeling as well as in the verifications. In the past segments of steel or an internal strutting of steel (DAUB 2013) placed around the later openings were commonly used, see Figure 1. The application of a strutting from the outside to the rings is restricted to such circumstances when for example a connection from a shaft to the tunnel can be made in suitable ground conditions (Ring and Glomp 2012). Though steel segments provide a robust solution, they are expensive due to their laborious manufacture, the high proportion of construction steel required and the time consuming installation in the tunnel (Häfliger 2013). A strutting of steel requires extensive design and verification. The resulting structure usually weighs several tons and must be erected as well as demounted within the confined space of the tunnel, requiring suitable transport and assembly equipment. The cross section remains restricted, thus causing a bottleneck for TBM operations and hindering the works and installations for the cross passage works."

Jan 1, 2016

By Z. Jin, D. DePaoli, P. Zhang

"Phosphate beneficiation in Florida generates more than one tonne of phosphatic clay, or slime, per tonne of phosphate rock produced. Since the start of the practice of large-scale washing and desliming for phosphate beneficiation, more than 2 Gt of slime has accumulated, containing approximately 600 Mt of phosphate rock, 600 kt of rare earth elements (REEs) and 80 million kilograms of uranium. The recovery of these valuable elements from the phosphatic clay is one of the most challenging endeavors in mineral processing, because the clay is extremely dilute, with an average solids concentration of 3 percent, and fine in size, with more than 50 percent having particle size smaller than 2 µm, and it contains nearly 50 percent clay minerals as well as large amounts of magnesium, iron and aluminum. With industry support and under funding from the Critical Materials Institute, the Florida Industrial and Phosphate Research Institute in conjunction with the Oak Ridge National Laboratory undertook the task to recover phosphorus, rare earths and uranium from Florida phosphatic clay. This paper presents the results from the preliminary testing of two approaches. The first approach involves three-stage cycloning using cyclones with diameters of 12.4 cm (5 in.), 5.08 cm (2 in.) and 2.54 cm (1 in.), respectively, to remove clay minerals followed by flotation and leaching. The second approach is a two-step leaching process. In the first step, selective leaching was conducted to remove magnesium, thus allowing the production of phosphoric acid suitable for the manufacture of diammonium phosphate (DAP) in the second leaching step. The results showed that multistage cycloning with small cyclones is necessary to remove clay minerals. Selective leaching at about pH 3.2 using sulfuric acid was found to be effective for removing more than 80 percent of magnesium from the feed with minimal loss of phosphorus.IntroductionFlorida phosphate ore, or “matrix,” as it is called locally, contains three different mineral groups that have to be separated from each other: (1) phosphate minerals, (2) clay minerals and (3) quartz, or sand. As mined, the phosphate and sand particles are embedded in compacted mud, or clay-balls. Before separation can begin, all of the particles must be liberated from the matrix of mud. The very first unit operation in the beneficiation process is to disaggregate the various particles. This actually starts while the matrix is flowing through the multimile pipeline from the mine to the beneficiation plant. While in the pipeline, the matrix is exposed to shear forces as it passes through the various centrifugal pumps along the pipeline. These intense shear forces cause a significant percentage of the sand and phosphate particles to be liberated from the clay-balls by the time they arrive at the plant. Once they reach the plant, the first goal is to finish disaggregating the clay, and follow that by making a size separation at 1 mm. This processing is conducted in the washer, consisting of a large rotating trammel screen and a few stages of log washer, screens and hydrocyclones. In all of the currently operating beneficiation plants, the washer is a large structure that receives the matrix, screens it and then discharges a pebble phosphate product sized larger than 1.0 mm and a slurry of liberated clay, sand and phosphate particles that are smaller than 1.0 mm."

Jan 1, 2017

By Edoardo Misano, Magali Schivre, Martino Semeraro, Alain Bochon

"INTRODUCTIONThe Laboratoire Souterrain de Modane (LSM) is an underground research laboratory located in the Western Alps on the French – Italian border. It is located in the middle of the 13km long Fréjus highway tunnel that links Modane (France) to Bardonecchia (Italy) in correspondence of the highest overburden of 1800m. The LSM current activity is mainly based on the investigations about the dark matter and requires very sensitive instrumentation which shall be protected from cosmic rays. To comply with the new legislation about safety in tunnels, the highway tunnels owners agreed in 2007 the construction of a parallel safety tunnel, at an average distance of 50m from the existing tunnel and the laboratory owner CNRS (Centre National de recherche scientifique) also decided to extend the existing laboratory with the construction of a new 17000 m3 cavern allowing the installation of wider and more powerful instruments that could increase chances of success of research. Preliminary studies stated that, considering both geological and functional issues, the most appropriate location for the new laboratory shall be in between the two tunnels and parallel to the existing laboratory (see Figure 1).Hence, the CNRS asked Systra, already in charge of the works supervision of the safety tunnel, to realize the design of the new cavern. The laboratory extension includes the construction of a 40 m long cavern with 300 m² cross section and two smaller tunnels connecting the safety tunnel and the existing laboratory to the new cavern. The minimum distance between the front face of the new LSM and the highway tunnel is about 25 m.The French and the Italian authorities, responsible of the exploitation of the Fréjus highway tunnel, asked the CNRS to develop an accurate study indicating that the construction of the laboratory extension would not have any negative impact on the existing structures of the highway tunnel. The main results of the developed study by Systra are summarized hereafter. The construction works should begin prior to the end of the construction works of the Fréjus safety tunnel in 2018."

Jan 1, 2016

By William Gleason

There was a time, not too long ago, when the most daunting challenges facing those in the mining and mineral processing industries could be solved through better technologies and better practices. But now the challenges that come from the actual acts of mining and processing are just part of the bigger picture. SME?s Colorado Section of the Mineral Processing Division (MPD) hosted its 63rd annual meeting at the Broadmoor Hotel in Colorado Springs, April 25-27 and, while the conference had its fair share or mineralolgy and processing presentations that were heavy on the technical side of things, this year?s conference was also focused on the issues of permitting, regulation compliance and legislative issues. The so-called ?softer? issues, that, if not addressed, can lead to very real and very hard challenges. Under the theme ?Mine your own business - permits, startups, expansions and resources,? even the most dedicated metallurgists were drawn into the discussions of politics and legislation, and how those issues affect their business. Fittingly, Colorado Mining Association (CMA) president Stuart Sanderson was honored with the Arthur C. Daman Lifetime Achievement Award. Sanderson, an outspoken proponent for the mining industry in Colorado and beyond, also presented the keynote address to the lunch crowd where he spoke about framing public opinion toward mining and the efforts of the CMA to move the public opinion dial in a direction more favorable to mining. Sanderson explained that Colorado, once a Republican stronghold, turned after 2002 and now is controlled by Democrats who are traditionally less supportive of the mining industry. Sanderson said the deciding factor in the power shift was money, as supporters of Democrats outspent Republicans in the most recent election cycles. CMA has done its part to keep mining going in the state with a broad marketing campaign that was outlined by Sanderson.

Aug 1, 2013

By Stephen H. Hall

INTRODUCTION At some point in the design and development stage of a mineral venture, the assay laboratory building, its interior layout, and major pieces of analytical equipment must be specified for construction or purchase. Even the most experienced chemist would have difficulty in proposing useful specifications without a good deal of investigation into the kinds of analytical tasks that the laboratory will be expected to address, the probable workload, and the operating time constraints. This chapter will provide a logical approach to laboratory design that starts with such an investigation. Specific examples throughout the chapter are drawn from the author's tenure as Chief Chemist at Barrick Mercur Gold Mines, Mercur, Utah, from 1982 to 1985. It is necessary to understand the nature of a modern production laboratory, and to recognize that its operations bear more resemblance to its parent processing plant than to a research, teaching, or custom analytical laboratory. The assay lab is a processing facility unto itself, where samples and reagents are the raw materials, and assay results are the final product. Its most efficient operating mode is as an assembly line, treating samples in a nearly continuous flow. Nevertheless , there are important differences between the lab and the process plant. The products - assays - are individually unknown quantities until they are "produced.' This can vastly complicate quality control compared to the process plant. Capital costs are general 1 y small compared to the plant, but the ratio of operating costs to capital costs for a laboratory is often very much higher than for the plant. This is due to the labor intensive nature of analytical work. For instance, during Fiscal Year 1984 at Barrick Mercur Gold Mines, labor costs for the laboratory staff represented about five percent of the total labor budget, while the laboratory building and equipment represented only about six-tenths of one percent of the original start-up capital. Failure to recognize both the similarities and differences between laboratory and plant operations is the foremost cause of difficulty encountered in designing a laboratory. The

Jan 1, 1986

By B. T. Stanley

Traditional methods of creating a water tight shaft liner involve the use of segmented or welded steel. When shafts are located in ground that exhibits extremely difficult conditions of high water inflow and hydraulic pressure, composite liners are often combined with ground freezing during construction. The authors were searching for a cost effective and more flexible solution to hydrostatic liners design than the traditional concrete/steel composite design used so far. Searching through new technologies developed for tunneling applications, sprayed on membranes systems seemed very promising but were not developed for the specific circumstances encountered in shaft sinking applications where ground freezing is involved. Even though freezing is a very effective technique, it creates adverse temperature conditions for the application of spray on membranes. In addition, application and hydrating cure times for those membranes products ranged between six to twenty-four hours under ideal conditions (usually temperatures well above freezing point), which eliminated them from consideration in a shaft sinking cycle. While researching different spray on membrane materials, it was discovered that Stirling Lloyd Polychem Ltd. has developed and proven a different membrane material for waterproofing liners in different tunneling applications. The characteristics of the membrane exceeds the pressure parameters encountered in frozen shaft sinking operations, and the chemical cure times were reduced to one hour per layer which worked well into the shaft sinking cycle times. More over their system included a quality control procedure that allowed insuring integrity of the membrane at application time, a very desirable feature for shaft liner construction. However, the frozen rock surface still presented an unknown in the cure time and stability equation. As all membrane products a shotcrete substrate is usually required prior to application. The hypothesis used by the author was to use this shotcrete layer, not only as a substrate, but also as a thermal insulation against the frozen rock and the membrane during both application and curing time. The authors knew from experience that shotcrete could be applied successfully over frozen rock. But the shotcrete temperature curve over time was unknown and no information were found in the available literature. Testing was required to determine whether a suitable mix of shotcrete could be applied to the frozen shaft wall to provide enough heat of hydration for a suitable period of time to create conditions suitable for membrane application and curing.

Jan 1, 2012

By Otto Braach, Wolfgang Frietzsche, Erdogan Gürkan

The Westerschelde Tunnel is located in the south of the Netherlands and links the two parts of the Provinces of Zeeland, Zeeuws-Vlaanderen and Zuid-Beveland, which are separated by the Westerschelde. Road traf?c has up till now taken the detour via Belgium or crossed by ferry. This unsatisfactory transport link signifies major economic disadvantages above all for Zeeuws-Vlaanderen. The first fixed link for road traffic between the communities of Terneuzen and Borsele are to be created by means of the two 6.6 km long tunnel tubes down to 65 m below sea level.

Jan 1, 2003

By R. K. Zipf

Recent scientific studies by researchers at the National Institute for Occupational Safety and Health (NIOSH) and the U.S. Army Corps of Engineers (USACE) presented the worst-case explosion pressures that can develop if a methane-air mixture of a certain composition and dimension accumulates and ignites within a sealed area of a mine. The Mine Safety and Health Administration (MSHA) issued its final rule on sealing of abandoned areas which considers potential explosion pressures and the risk of achieving the necessary conditions. The new MSHA seals regulation has increased the pressure design criteria an order of magnitude beyond the old standard of 140 kPa (20 psi) to 800 kPa (120 psi). However, there still are major knowledge gaps pertaining to seals and sealed areas including: (1) the composition of the sealed area atmosphere and how it changes in time and space, (2) explosion pressures that might actually develop within sealed areas, (3) engineering procedures to follow when designing seals and seal installations, and (4) guidelines to manage the atmosphere within sealed areas with monitoring or inertization. NIOSH has initiated a seals research program with collaborators from Safety in Mines Testing and Research Station (SIMTARS) in Australia, West Virginia University (WVU), the Naval Research Laboratory (NRL), and USACE. Highlights of progress so far include: (1) construction of a gas explosion tube at Lake Lynn Laboratory for studying large methane-air explosions, (2) computer simulation of the fluid dynamics of high pressure methane-air explosions, (3) development of seal analysis methods considering construction materials, reinforcement and the seal foundation, and (4) development and testing of innovative seal designs that utilize inexpensive, readily-available rock rubble to resist high explosion pressures. NIOSH researchers aim to provide sound engineering guidelines to better address the new MSHA seal regulations. DISCLAIMER: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By James M. Johnson, David Landriault, Frank Palkovits

The term “Paste Technology” was first used in the late 1980’s. It was used to describe a high fines (15 wt% or greater minus 20 microns), low water content backfill material that could be transported underground through a borehole/pipeline distribution system (4” to 8” dia.) at a yield stress similar to fresh concrete (100 to 400 centipoise). This “Paste Backfill”, unlike slurry transported backfills does not segregate into separate solid and liquid phases at low pipeline transport velocities or upon disposal into the underground stope. Paste backfills can consist solely of fine material, or can include fines plus sand and aggregate similar to a concrete mix. Pipeline transport of paste requires that sufficient fine material (minus 20 micron content) is contained within the mix to lubricate the pipeline walls to create a plug flow condition. For concrete, the fine material is supplied through the cement addition to achieve high compressive strength. For paste, the fine material is generally available in large quantities in the form of mill tailings. The paste tailings can be transported underground for use as backfill or discharged on the surface in a tailings management facility (TMF). This natural abundance of fine grained material is not exclusive to mine tailings but is common to many waste streams in many different industries. This makes the disposal of many waste materials very amenable to paste pipeline transport and placement as a non-segregating slurry. The potential use of paste technology for a wider group of waste materials was realized by these authors and others over two decades ago. Through the effort of this small group the use of paste technology has expanded over the years to become recognized as a low cost, environmentally superior, and technologically controllable method of transporting and placing specific material waste streams with a low water content and high placement density. The high yield stress nature of a paste also lends itself well to the blending of one or more coarse waste materials into the fine waste material paste stream. This allows all the waste materials to be transported by pipeline, increases their placement density; decreases the supernatant release/treatment, reduces contaminant mobilization, hydraulic conductivity and oxygen/water reactivity through encapsulation in the paste matrix. The following paper describes the present state-of-the-art use of paste technology in the world today. It also describes future uses of the technology that are under development and speculates on the overall use of the technology for waste management in the future.

Jan 1, 2005

Allis Mineral Systems' Grate- Kiln system can economically convert low-grade iron ore into high- grade iron-ore pellets suitable as feed material for blast furnaces for making steel. These pellets can also be fed to a direct reduction process for making sponge iron. The Grate- Car system combines the company's [ ] Grate-Kiln system for iron-ore pelletizing and Accar system for iron- ore reduction. The Grate-Car system consists of a traveling grate, a ported rotary kiln and a rotary cooler that are coupled in series. This system eliminates the pelletizing plant's rotary kiln and annular cooler. It reduces the need for some auxiliary equipment. This results in lower capital cost and lower energy consumption. The traveling grate provides that static bed handling necessary for heat hardening pellets before their discharge into the kiln. The ported kiln provides the reducing atmosphere with a more precise means of controlling the kiln axial temperature profile than conventional rotary kilns.

Jan 1, 1997

By Tetsuo Yamazaki

Natural cold seepages are characterized as rapid upward transports of methane from deeper parts of geological structures to the seafloor. Thermogenic and/or biogenic methane generated in deep sediments moves up to seafloor, and major part of methane is consumed in anaerobic oxidation of methane (AOM) and hydrogen sulfide is created in anaerobic sulfate reduction by consortium of microorganisms. Then the hydrogen sulfide is utilized by chemosynthetic communities near the seafloor, such as Acharax, Calyptogena, Bathymodiolus, and the mat-forming bacteria Beggiatoa (Fig. 1). When the supply of methane is large or rapid, remaining methane escapes from seafloor, and it is aerobically oxidized in seawater. A mass balance ecosystem model of chemosynthetic community around natural cold seepages in sediment layer and on seafloor has been created and improved by the authors (Yamazaki et al., 2005; Takeuchi et al., 2007). The model is constructed from 3 main processes as schematically shown in Fig. 2: (1) Methane supply process; (2) Ecosystem process; (3) Water column process. The part of chemosynthetic communities is in the ecosystem process. A numerical model CANDI (Carbon And Nutrient Diagenesis) was developed by Boudreau (1996) to simulate the biogeochemical processes such as organic matter, oxidant, nutrient, bi-product, and pH diagenesis in aquatic surface sediments. Then, the improved version named C. CANDI was developed (Luff and Wallmann, 2003; Luff et al., 2004). The authors created the same type carbon and nutrient diagenesis process model with calcium carbonate formation like C. CANDI (Yamazaki et al., 2005), and have added the sulfur oxidizing and immobilization processes (Takeuchi et al., 2007). The sulfur oxidizing and immobilization processes are connected with the carbon and nutrient diagenesis process model.

Jan 1, 2008

By M. J. Virnig, Marc Le Vier, Rong Yu Wan, Jan D. Miller

Although most gold production from primary resources is achieved by cyanidation, many research activities have focused on alternative processes using noncyanide lixiviants. Such research has been prompted by environmental concerns and problems associated with the processing of refractory gold ores. Numerous research projects have been conducted to search for a noncyanide hydrometallurgical process for gold extraction. In this paper, a technical review of gold recovery from noncyanide solutions is presented, and new results are reported. Gold recovery techniques that are considered include activated carbon adsorption, cementation, solvent extraction, ion exchange, and reduction-precipitation.

Jan 1, 1993

By P. J. Ryan

Phelps Dodge’s Candelaria copper-gold mine is located 20 km (12miles) south of Copiapó in northern Chile’s Atacama province (Region III) (Fig. 1). The Candelaria Mine is about 800 km (500miles) north of Santiago and 75 km (47 miles) east of the Pacific Ocean. Its elevation is 600 m (1,970 ft) above sea level. The Copiapó River Valley is 6 km (4 miles) northeast of the mine site. It is the only major source of water in this arid region. The average rainfall is 14mm/a (0.5 in./year). During 1995, the mine produced 521.4 kt (574,800 st) of copper concentrate containing 150 kt (165,000 st) of salable copper and 3 t (98,800 oz) of gold. The 1995 unit cash cost was less than 50 cents/lb of copper. This makes Candelaria one the world’s lowest cost copper producers.

Jan 1, 1996

By Darrell V. B. . McClarty

In 1996, Rio Algom, Denison Mines and the Elliot Lake Research Field Station (ELRFS) formed a consortium to implement a regional environmental information management system (REIMS) for the Elliot Lake area in Ontario, Canada. ELRFS is an affiliate of Laurentian University in Sudbury, Ontario, The discovery of uranium in the Elliot Lake region in post-World War II led to the development of 12 mines and 11 associated mills between 1955 and 1958. During the late 1980s, declining world demand for uranium, combined with the discovery of high-grade uranium ore in other areas of the world, made the Elliot Lake mines uneconomical. As a result, all area mines ceased opera¬tions by the end of 1996. The eight facilities and three tailings management areas operated by Denison Mines and Rio Algom's five mining waste management areas contain 150 Mt (165 million st) of potentially acid-generating tailings. The areas cover 13.2 km2 (3,265 acres) and receive drainage from an additional 13 km2 (3,212 acres). The primary objective of the joint initiative was to implement a personal-computer-based, regional, environmental-information management system for managing historical data and ongoing environmental programs in the Elliot Lake region. The Elliot Lake consortium decided it needed an information system with an integrated, process-oriented and requirements-driven approach to collect and manage the environmental information. Following a study of environmental information management systems currently used by the mining industry, the consortium decided to base REIMS on the "Envista" product. This is a commercially available, environmental information management system marketed by Envista Technologies of Saskatoon, Canada.

Jan 1, 1999

By Thomas E. Shufflebarger

Glass is one of man's most versatile creations. ---The earliest glaze known---is about 12,000 B.C. ---The oldest pure glass is a moulded amulet of about 7,000 B.C.---. Indicative of a knowledge of properly-proportioned, quality raw-material, means were found for producing the first relatively clear, transparent glass at about the beginning of the Christian era. The fundamentals of almost all the modern, technical processes of manufacture were established during the 3rd Century. (1) Glassmaking, practiced in Colonial America, was moved toward the Ohio Valley in response to increasing demands for fuel. This move, beginning in the 1860's resulted in the use of the glass sands contained in the Oriskany (and St. Peter) sandstone. (2) Glass sand,(3) virtually pure, fine-to-medium-grained quartz sand(4) is the principal raw material used in the manufacture of glass; it constitutes proportions which range to a maximum of about 72% and seldom is glass made without it. However, acceptable glass sands are, invariably, those which most nearly fit the glass-producer's economic needs and any method used to evaluate a raw material's potential must finally prove equatable with such needs. As used in the United States, source-rocks of glass sand include sandstone, unconsolidated silica sands, quartzites and vein-quartz. Admixtures of silica sand and other (principally clay and feldspar), readily separable components have been proven viable. However, the silica sand, refined by nature to a high degree of purity, is the desirable product of exploration. If the term, standard, is justified by long-continued use, the Oriskany - and St. Peter sandstones are, together, the nonesuch of the glass sand industry they provide the principal tonnage of melting sand. According to Grimsley,(5) Ottawa, Illinois, glass-sand is considered the standard glass-sand of the West and the analyses of Berkeley Springs sand (Oriskany) compare most favorably with this sand.

Jan 1, 1974

By L. A. Ruth

Introduction The US Department of Energy's Office of Fossil Energy has begun a new approach for developing the ultra-clean energy plants. This approach will allow the nation to continue to use low-cost fossil fuel feedstocks during the early decades of the 21st century. The new approach is called Vision 21. The overall goal is to effectively eliminate, at competitive costs, environmental concerns associated with the use of fossil fuels for producing electricity and transportation fuels. Vision 21 is based on the following three premises: •The nation will need to rely on fossil fuels for a major share of our energy needs well into the 21st century. •It makes good sense to rely on a diverse mix of energy resources, including coal, gas,

Jan 1, 2003

By A. Frederick Banfield

Various modeling techniques are available for describing ore deposits on the computer. Multiple seam coal deposits can be quite successfully modeled by using the variable block modeling method. In essence, this type of model provides an efficient method for storing the relevant data required for calculating ore reserves and for performing the mine planning. The main advantages of the variable block model over other methods for modeling irregular block or tabular deposits are: 1) The amount of data that has to be stored is minimal, i.e., the most efficient use of computer space is made since only the pertinent seam and topographic geometries need to be stored. 2) The computer logic necessary for calculating ore reserves and performing mine sequencing is relatively simple as compared to the logic that would be required for the three-dimensional block model. 3) A variable block model can be created either by starting from raw drill-hole data or by digitizing cross sections that contain the geologic interpretations. 4) Updating individual or multiple blocks can be performed with relative ease. 5) Display of the model is relatively inexpensive and easy to perform. The objective of this chapter is to describe a developed procedure as used in applying the variable block model to a specific multiple seam coal deposit. The general sequence of operations includes: (1) develop the computer model, (2) design the open-pit limits, (3) compute reserves, and (4) develop a long-range mining plan. The programs developed for this application are an expansion of MINTEC's MEDSYSTEM software. It should be noted that this is just one of many possible applications of the developed variable block model.

Jan 1, 1979

By Eric Lutz

"Great effort has been expended for more than 40 years to improve the workplace safety and health of surface and underground miners across the United States. When looking at the past decade, withstanding the 2010, Upper Big Branch (UBB) disaster that took the lives of 29 miners, this effort has resulted in a generally decreasing trend from 57 fatalities (22 coal; 35 metal/non-metal) in 2005, to 45 (16 coal; 29 m/ nm) in 2014. Through August of this year, there have been 23 mining-related deaths (eight coal; 15 m/nm). These results reflect continued diligence and perseverance on the part of miners that stay true to our legacy; and demonstrate significant investments from mine-site leadership, mining corporations, and state and federal regulators. However, over the past five years there have been an average of 32 fatalities per year, with a low of 36 (2011 and 2012) to a high of 45 (2014). If we know that there will be somewhere between 30 and 50 mining related deaths next year, which of us will volunteer to be counted as one of the numbered? Clearly, we all agree that one fatality is too many; and as evidenced by changes following UBB, deaths in any sector are deaths reflective of all mining across all sectors.The impact of each miner death touches us all. Miner’s deaths are felt deeply by family and friends, most significantly the children; their communities in which they served, supported, and worshiped; and by society that has lost a hardworking, dependable contributor. Further, to take a slightly cynical, but realistic view, miner fatality events impact the financial vitality of mining and contracting companies and broadly diminish investor confidence. Just as important, these events significantly impact our communities and result in negative public perceptions, which ultimately drive regulatory policy and related compliance pressures. This resulting pressure forces operations to broadly address safety and health gaps in very specific ways (i.e., see U.S. Mine Safety and Health Administration (MSHA) regulations regarding lids for trash cans) minimizing a mine site’s opportunities for operational flexibility. To break this cycle that is the operational reality, mining companies are focusing tremendous efforts on fatality prevention and specifically on dedicated investment to prevent multiple fatality events."

Jan 1, 2015

By C. P. Wa1ters

This paper is written primarily from the standpoint of the miner and consumer of Missouri fireclays in refractory products, principally firebrick used in the linings of blast furnaces, hot metal transfer cars, the recuperators of glass melting tanks, and other allied uses involving contact with liquid metals and reactive slags. For these uses the manufacturing plant requires forecast of certain physical characteristics, as well as chemical characteristics, of the raw clays as a determination of practicability of mining, treatment such as pre -firing or calcining, and final usage area. These methods and results may leave something to be desired from an academic view, but are used my operation as an on-running guide to seeking and mining raw material. The high quality fireclays of Missouri are generally differentiated by the user as the softer, somewhat plastic, "bond" clays and the so-called flint clays suitable for a fired or unfired aggregate portion of a brick composition. The semi-plastic "bond" clays are mined in a producing area of northeast Missouri including Montgomery, Audrain, Callaway, Monroe, and Lincoln counties. In this geographic area the clays are the members of the cheltenham formation and occur in rather large lenses in which the usable members may approach 15 meters in thickness and an area of 6o to 8o acres. Overburden is dependent on the surface topography and, in our operations, varies from 8 meters to 25 meters. It can be up to 36 meters in the prairie uplands, but this is rarely strip mined. There was former mining by shaft and drift methods in which the overlying coal was also worked. These clays are primarily used as a binding material for other clay aggregates and is characterized by its lower refractoriness-cone 3o (165o c) to cone 321/2 (172o c), in terms of pyrometric cone equivalent, and an alumina - Al2o3 - content of plus or minus 31%. Physically, these clays are readily slaked by water to a fine grain size and exhibit a degree of

Jan 1, 1977

By Irene Bendanillo, Canon Cheung, Justin Lianides, Derek Penrice

The SLAC National Accelerator Laboratory’s two-mile-long particle accelerator generates the world’s brightest X-rays from its Linac Coherent Light Source (LCLS) freeelectron laser. This facility has driven groundbreaking discoveries in medicine and industry. The LCLS-II-HE project will provide a significant increase in laser energy, allowing cutting-edge research in fields including biology and environmental science. A key project component is the Low Emittance Injector Tunnel (LEIT), a 240-foot-long tunnel to be built alongside the existing accelerator and connected to it via a 30-footlong Transfer Tunnel. This paper discusses site and scientific constraints that led to the selection of the LEIT configuration: tunnels to be constructed using the sequential excavation method in mixed-face conditions comprising native rock and placed backfill, and critical design considerations including protection of overlying and adjacent historic structures and structural accommodation of near-fault seismic loading.

Jun 13, 2023