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By Yukika Miyashita, Takahiro Inoue, Kenji Namikawa, Masashi Matsumoto, Junichi Koseki, Yoshihiro Terashima

"In order to construct an underground two-layer expressway branch junction structure with a height of 14.7 m and a width of 22.3 m, two shield tunnels in each layer were combined by using a non-cut-and-cover enlargement method in sedimentary soft rock. Before and during the construction work, preliminary analysis, in-situ investigations and laboratory tests were conducted to ensure the construction safety and to evaluate the deformation characteristics of sedimentary soft rock. The construction project was safely executed without any water leakage or collapse of tunnel working face. The predicted results from preliminary analysis were almost similar to the measured values. From the detailed investigation of measured results, it was confirmed that the deformation characteristic of the sedimentary soft rock was observed to a small extent as the ground deformation derived from construction work. INTRODUCTION In recent years, some newly constructed urban expressways in Japan are being planned as underground structures due to the consideration of roadside environment. The construction of such underground expressways is frequently conducted using a shield tunneling, a typical one of non-cut-and-cover methods, to prevent any adverse effect to traffic in arterial roads, operation of nearby commercial establishments, and daily lives of local residents during construction work. For underground urban expressway, the connections with existing road network on ground surface or on elevated sections are indispensable, which require the construction of an underground branch junction with large cross-section. This raises a technical difficulty regardless of the open-cut or non-open-cut construction method."

Jan 1, 2016

By Dale W. Norris, John A. L. Campbell

INTRODUCTION Optimization, as measured by productivity gains, is being achieved in our nation's preparation plants principally by automation, economy of scale, and reducing maintenance. Increased tonnage per unit of investment, a1 so a measure of optimization, is being achieved by breaking with tradition and increasing plant utilization, while simultaneously improving on equipment re1iabi1ity. Improved qua1ity, another measure of optimization, is being attained through technical innovation. This review will concentrate on state-of-the- art unit operations and processes, and will not discuss emerging new technologies which are covered in detail in other presentations of this symposium. It is recognized that much of what will be discussed in this paper is not unique to the fine coal circuit, but is equally applicable to the entire preparation plant. However, the areas reviewed are the principal means being used today to optimize an existing preparation plant's fine coal circuit. Prior to designing and optimizing a fine coal cleaning circuit, the question that must first be answered is, "Do we even want a fine coal circuit? This is a much more complex question than is readily apparent, as most of you recognize. It can be argued either way. In the final analysis the "bottom line" will hold (Blackmore, 1982). If your sales contract a1 lows it, and the selling price can justify it, you most assuredly want to build a fine coal circuit into your preparation plant. In general today, most new preparation plants do have fine coal cleaning circuits. The purpose of fine coal cleaning has changed with time. Some of the early applications of fine coal cleaning were to prevent stream pollution rather than to prepare a product for market (Merrill a Pennington, 1962). During the 50's, 60's and into the 70's the principal thrust of fine coal cleaning was in metallurgical coal preparation. More recently, the emphasis of the 80's is on steam coal processing. There is no consensus on what is fine coal. Traditionally, fine coal would be anything below 1/4" in size. Because of the advances being made in intermediate coal cleaning processes, i.e. heavy media cyclones and jig cleaning, this discussion will define fine coal as -28 mesh (Aplan, 1987). Figure 1 is a plot of the size ranges of a large number of U.S. bituminous coals. In general the -28 mesh fraction of a bituminous coal will be between 7% and 18% of the ROM feed with reported ranges of 5% to 40% (Aplan, 1987). Consequently, traditional fine coal cleaning is general 1 y involved with a re1 actively mi nor portion of the coal feed. Every effort is taken both in terms of mining and preparation to keep it that way because of the high cost of cleaning fines. The move away from this posture, namely, the techniques to fine grind coal to liberate pyrite is probably the biggest challenge facing fine coal processing today.

Jan 1, 1988

By James R. Aggson, Verne E. Hooker

GENERAL CONSIDERATIONS The design of a mine or any underground opening in rock is similar to the design of any other structure, such as a building or a bridge, in one important way. This similarity lies in the fact that the stability of the structure is a function of the loads that will be applied during the structure's expected lifetime. In the case of an underground opening, the applied load is the product of the existing in situ stress field and the concentration of this field that is produced by the extraction of a load¬bearing material. Thus, a knowledge of the in situ stress field is considered a basic requirement in the design process and essential to the eventual stability of the underground structure (Duvall, 1976; Obert, 1972; Merrill and Peterson, 1961; Dahl and von Schonfeldt, 1976; Hedley and Wilson, 1975). The in situ stress field can be used along with the physical properties of the rock masses involved, the ge¬ometry of the various rock types, the geometry of the openings involved, and a failure criterion to evaluate structural stability of a planned mine by theoretical or numerical techniques. This same information can be used to investigate ground control problems in existing mines. In situ rock stress determinations can be separated into three categories: the determination of applied stress, also called the absolute or field stress; the deter¬mination of concentrations of the field stress near open¬ ings; and the determination of changes in rock stress as load-bearing material is removed. The applied stress field is more difficult to determine than are stress changes. Various instruments and techniques have been developed to determine applied rock stress and stress changes in rock. ABSOLUTE OR FIELD STRESSES Theoretical Considerations In the absence of actual measurements, it is often assumed that at any point, the vertical stress is equal to the weight of the overlying material. [ ] where S„ is vertical stress, S is average weight density of overburden rock, and h is depth from the surface. This is normally consistent with actual experience. The horizontal stresses are assumed to be equal and related to the vertical stress through the Poisson effect. [] where Sh is horizontal stress, S„ is vertical stress, and v is Poisson's ratio. The derivation of Eq. 2 is dependent on lateral con¬finement of the rock mass. An increasing amount of information is rapidly becoming available which indi¬cates that the in situ stress field at a particular location cannot simply be assumed to be a gravity-induced stress distribution in which the secondary principal stresses in the horizontal plane are due to confinement and Pois¬son's effect. Rather they can be a complex function of gravity loading, regional stresses, structural features, ex¬cavation geometries, and variations in surface and/or possibly basement rock topography. Furthermore, the underground principal stress dis¬tribution is not necessarily vertical and horizontal as is often assumed. The deviation of the three-dimensional stress distribution from vertical and horizontal can be due to a combination of both topographic (Hooker, Bickel, and Aggson, 1972) and structural features.

Jan 1, 1982

By M. Murphy

The multibillion dollar cost of cleaning up thousands of environmentally contaminated sites across the country created by decades of inadequate disposal of hazardous waste has led to a search for "deep-pocket" sources of cleanup funds. The resul1:: is the emergence of a growing body of law that could have a profound impact on commercial financing transactions and other investment activities when present or past owners of contaminated property are involved.

Jan 1, 1988

By Paolo M. Brion, Z. Bade Sozer

"The Bypass Tunnel has high head conditions ranging from a minimum of 600 feet (183 m) under the Hudson River to a maximum of 875 feet (267 m) on the west side. The ground cover ranges from 425 feet to 900 feet (130 to 274 m). A two-pass lining is designed for the Bypass Tunnel. The bolted, gasketed precast segments carry the temporary hydrostatic and permanent ground loads. After the tunnel is put into service, the design assumes that the final lining, which varies from reinforced concrete to reinforced concrete with steel interliner, will carry the permanent hydrostatic loads. The design head for the segments is assumed at 775 feet (236 m), and the internal operating pressure head is around 1,200 feet (366 m). This paper discusses the design hydrostatic head and different load conditions considered for the segments, the load sharing between the segments and final lining, and the means employed to control water and hydrostatic pressure. PROJECT BACKGROUND The Rondout-West Branch Tunnel (RWBT), a segment of the Delaware Aqueduct, was built from 1937 to 1944 and provides about 50% of New York City’s total water supply. Monitoring and tunnel operations have shown that the RWBT is leaking up to 35 million gallons per day (MGD) (132.5 million L/day). In particular, two locations have been identified as areas of concern: Roseton and Wawarsing, as shown in Figure 1. The Wawarsing reach of the aqueduct will be repaired with an extensive grouting program when the RWBT is unwatered. However, because of the extensive nature of the leakage in the Roseton area, a Bypass Tunnel will be constructed to divert the flow around this area."

Jan 1, 2016

By T. J. Toy

The topography reconstructed following land disturbance is the foundation for all other reclamation practices. As the manufactured drainage basins, hillslopes, and stream channels approach a steady-state condition, the amount of adjustment of these landforms by geomorphic processes following reclamation decreases. As the adjustment required to establish a steady-state condition decreases, the prospect of reclamation success increases while the prospect of site maintenance decreases. Careful topographic reconstruction is a good investment.

Jan 1, 2002

By M. T. Errington, P. C. Miller, W. E. Hardwick

Paper discusses in general terms the techno economic merits of various types of aerated biological reaction systems. The current status of the technology leaves many questions unanswered and hence the choice of the best system to employ is open to discussion. Reasons are given for the choice of the reactor system to be built and operated by Davy McKee. The pilot plant has been designed to provide answers to a number of the questions posed by this technology.

Jan 1, 1998

By P. G. Semple

For the last four years, the Kilborn Group of Companies (Kilborn) has been involved in several major projects in the CIS. These projects include the Kumtor Project, the Kubaka Gold Project, the Kazgold Project, the Aginskoe Project and the Jerooy Project. These projects are all in various stages of detailed engineering and construction. In this paper, Kilborn will discuss our experience in the CIS and share some insight into project development in this geographic region.

Jan 1, 1996

By Nora M. Hutt, Kevin A. Morin

There is currently some pessimism over mixing of net-acid-neutralizing (NAN) and net-acid-generating (NAG) rock to obtain indefinite near-neutral seepage from mined-rock piles. This is due in large part to the lack of well- documented, successful cases of blending and layering, and to the knowledge of unsuccessful attempts. Past work often defined a potentially successful mix in terms of the ratio of net-acid-neutralizing rock to net-acid-generating rock. For example, one case study indicated the bulk pile-wide ratio was approximately 3: 1. Since this exceeded a common ratio used in acid-base accounting, no acidic drainage was predicted. However, acidic drainage appeared within two years. A large part of the ambiguity in mixing arises from attempts to predict success based on a ratio. This paper looks in detail at simple discrete-zone mixing, where at least one truckload of NAG rock is placed in a particular location with no further rehandling or dozing. The lack of acidic drainage in this scenario is dependent on the intervening distance between the discrete NAG zones, along flowpaths occupied by NAN rock. Calculations show that the bulk mixing ratio of a mined-rock pile is not an accurate indication of whether near-neutral drainage can be maintained. For example, a pile with a bulk ratio around 300: 1 could still release some acidic drainage. Calculations also show that the minimum separation distance of the NAG zones (L) can be so great, even with typical NAG and NAN rock, that the mixed pile could safely contain only a few percent of NAG rock, which would not be sufficient for many minesites with NAG rock. The comparison to a more elaborate, computer-based statistical model shows that the simple discrete-zone approach will provide a reliable yes-no indication of whether any acidic drainage will leave a pile. However, predictions of whether combined downstream drainages will be acidic depend on numerous site-specific physical and geochemical factors within and below a pile that cannot be modelled in a general way, like the number of flowpaths and the nature of their intersections.

Jan 1, 2000

By D. R. Spears, D. A. Stanley

The US Bureau of Mines investigated the fundamental aspects of shear-flocculation using a rapid, in-situ particle size analyzer. Silica was stirred in the presence of an aliphatic amine to determine the effects of collector coverage, stirring speed and solids concentration on the kinetics of shear-flocculation. The results showed that shear flocculation is a two-stage process. In the first stage, which occurs during the first 1-2 min. of the reaction, the mean particle size increases rapidly, and in the second stage, an equilibrium is set up between the rates of floc growth and floc decay. Collector dosage affected the position of the equilibrium by altering the number of surface sites for particle-particle attachment. A minimum stirring speed was necessary for shear flocculation, which was dependent on solids concentration and collector dosage. This stirring speed was the minimum necessary for particles to overcome the electrostatic energy barrier, and that results in keeping the conditioned particles dispersed. Larger particles flocculated more rapidly. At very high stirring speeds, large flocs became unstable, resulting in a narrowed particle size distribution in the slurry.

Jan 1, 1995

By J. D. Carson

A 0.60 km2 (150 acre) wetland was reclaimed by Agrico Mining Company as part of a 1.48 km2 (366 acre) reclamation program in southwest Polk County, Florida approved by the Florida Department of Natural Resources. The upland portion of the area provides watershed for the wetland site which overflows into the flood plain of Payne Creek. Construction of the wetland was designed to provide conditions favorable for a diversity of habitats, as well as retention time for surface runoff waters. A variety of revegetation methods, including innoculation with muck from unmined wetland depressions, have produced encouraging results with both woody and herbaceous species.

Jan 1, 1983

By A. N. Islam, C. Simons, M. N. Hughes, J. Barrett

The effluent from the bio-oxidation of arsenopyrite contains high concentrations of iron(III) and arsenic(V), the pH being in the range 1.0-1.3. The use of lime to increase the pH causes the precipitation of calcium sulfate, calcium arsenate and a mixture of solids containing calcium, iron and arsenic. The presence of calcium is due to slaked lime encapsulated by the iron arsenate precipitates. These iron arsenate solids are related to known minerals. The use of sodium hydroxide to effect the precipitation of iron and arsenic produces solids which are more stable than those produce by using slaked lime. The use of limewater produces an initial precipitate of calcium arsenate.

Jan 1, 1991

By L. Sletmoen, P. Rocque, E. DeSouza

Plans for achieving planned production rates at the Red Lake Mine High Grade Ore Zone required that the mine ventilation system be upgraded. Time constraints required that only a site assessment of the mine ventilation system be performed followed by recommendations for providing adequate ventilation conditions at the production zone. This paper describes the engineering assessment, design and commissioning of the ventilation system upgrade for achieving increased flows at the high grade ore zone. The work was successfully achieved with minimal capital expenditures and disruption to the mining cycle.

Jan 1, 2003

By J. Frostiak

The Campbell gold operation of Placer Dome Inc. produces an arsenopyrite-sulphide concentrate which must be treated either by roasting, biooxidation or by pressure oxidation to obtain high gold recoveries. Pressure oxidation is a proven process and has the inherent advantage of meeting the stringent environmental regulations in the province of Ontario. A comparison of biooxidation and pressure oxidation was completed early in 1990 and the latter was selected by Placer Dome as the preferred process for replacement of the roasters. The commercial plant design was based on technology supplied by Sherritt Gordon and in July of 1991, the existing roaster operation was shut down and a new pressure oxidation plant was commissioned. The following summary describes the start up of the new facility and presents typical operating data.

Jan 1, 1992

By Chee S. Theng

As the 2016 president of the Society for Mining, Metallurgy & Exploration Inc., I am pleased to present the 2016 issue of the Transactions of the Society for Mining, Metallurgy & Exploration Inc., Vol. 340. A significant portion of the contribution that we make as a professional society is the publication of professional and technical papers that accelerate the advancement of scientific knowledge and enable the transfer of technology. Communication within the mining community is the key to a successful society. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, PA, that resulted in the founding of the American Institute of Mining, Metallurgical and Petroleum Engineers (AIME). Those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume fulfills that pledge. The 2016 Transactions contains some of the most interesting research and insights from the past year and features an international slate of authors spanning industry, academia and government. Papers include the latest findings from the U.S. National Institute for Occupational Safety and Health (NIOSH) and special-issue articles on process development testing. The 2016 Transactions consists of a total of 65 technical papers, encompassing all 21 papers published in 2016 in the Technical Papers Section of Mining Engineering (Vol. 68) and all 27 papers published in 2016 in Minerals & Metallurgical Processing (Vol. 33). Additionally, this volume contains 17 papers that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All of the technical papers were peer-reviewed. The process of review and publication requires much hard work by authors, reviewers and our publications staff. As the 2016 president of SME and on behalf of all our members, I would like to extend our gratitude to all whose volunteer efforts contributed to the publication of this volume.

Jan 1, 2016

By Timothy P. Smirnoff, Anthony Stirbys, Amanda Elioff

The construction of the continuing expansion of the Los Angeles Metro System has required the construction of eight new station structures. One contractor proposed, as a construction alternative for the support of excavation of the Hollywood/Vine Station, the use of soil-mix walls instead of the conventional soldier piles and wood lagging. Soldier piles and shotcrete or wood lagging support systems had been generally used on the other sub-way station excavations constructed to date throughout the system. Immediately east of that station and in almost exactly the same geology, the Hollywood/Western Station was being excavated at the same time using a conventional support system. This paper com-pares the performance of these two support systems in the alluvial soils of the Los Angeles Basin.

Jan 1, 1997

By Th. Petropulos

The Zn-Ag-Pb mineralization zone near Molai (Greece) was explored by more, than 60 drillholes. Promising results led to the decision of additional drillholes in order to confirm the expected spatial extension of the deposit. A multiobjective approach is described which optimizes the location of a set of 5 additional drillholes. The decision is based on estimation errors for grade, thickness and depth of the main ore bearing layer, with respect to cut-off values for grade and thickness. The linear combination of these variables defines a favorability index which is used for mapping optimal drillhole locations. The map shows several clusters of favorable cells. A declustrering algorithm is used to select a representative cell for drilling in each cluster.

Jan 1, 1989

By Harald F. Solberg

A preliminary study of the performance of a 4-inch Krebs cyclone at near rope conditions and different feed slurry temperatures was completed. Results suggest that temperature influences the x50c size which, in turn, did not depend upon spigot diameter. The bypass correction to a reduced efficiency equation incorporating the concept of a critical size xo was a function of fractional water recovery to underflow and may depend on feed size and feed percent solids. Further experimentation is required to develop an accurate model at near rope conditions.

Jan 1, 1981

By G. M. Wilemon, B. J. Scheiner

The Bureau of Mines conducted investigations on extracting phosphate values from fine-particle wastes generated during the mining and beneficiation of phosphate ore by leaching dried wastes using a H2SO4-methanol mixture. Although phosphatic clay waste contains up to a third of the phosphate originally present in the ore, recovery of these values represents a significant challenge due to the fine grain size of the material, the particles averaging less than one micrometer in diameter. Waste samples obtained from two Florida producers yielded phosphate extractions of 71 and 84 pct, respectively, when leached under ambient conditions and at a stoichiometric acid ratio of 1.4:l. Elevated temperatures did not improve the amount of phosphate extracted. Undesirable A12O3, Fe2O3, and PlgO impurities were largely rejected; higher grade wastes gave acids that meet established industry impurity standards and lower grade samples yielded acids that marginally fell short of the standard. Separation of the crude acids from the insoluble residues was accomplished via vacuum filtration through either filter paper or commercial filter cloths. Both filtration rates and solids retention were improved by the addition of 0.5 lb/ton of poly(viny1 acetate) (PVAc) or poly(ethy1ene oxide) (PEO) to the methanol-acid slurries. These results show potential for substantially increasing the reserves of an important domestic resource.

Jan 1, 1989

By A. T. Iannacchione

Recent fatal injuries occurring during pillar retreat coal mining call for better identification of the hazards and recognition of risks. Ground control hazards associated with room-and-pillar retreat mining tend to intensify with depth, requiring extra precautions in the form of additional controls. In many locations these activities are further complicated by local complexities often associated with unique or novel circumstances, such as over-mining or under-mining. One technique recently studied by NIOSH, Major Hazard Risk Assessment (MHRA), may help mine operators to mitigate the risks associated with pillar recovery operations. The approach was trialed at two underground coal mines in southern West Virginia that are currently practicing pillar recovery. The first step in the MHRA process involved reviewing the segments or parts of the pillar extraction mining system and identifying associated hazards and threats to the operation. Some of the high risk hazards at these two sites included: ? Rock fall during pillar extraction covers equipment and injury occurs during recovery operations, ? Rock fall above the roof bolt horizon, potentially injuring ? workers and/or requiring recovery action, ? Rib fall under deep cover, potentially injuring workers, and; ? Strata instabilities associated with subsidence of the interburden due to simultaneously mining two seams in close vertical proximity to one another. The mines? risk assessment teams then considered each threat individually in order to systematically identify potential unwanted events. The top unwanted events were examined individually using structured risk analysis tools. The output from the process includes a list of priority existing controls for monitoring and auditing, and a second list of potential new controls. These controls consisted of: Examples of best practices, ? Enhanced communication, ? Implementing standard operating procedures (SOP), ? Protocols for emergency response actions, ? Effective layouts, ? Efficient monitoring, and; ? Successful audits. This paper documents the process as it unfolded at the two mines, and analyzes the strengths and weaknesses of the MHRA technique as it applies to pillar recovery operations. This work was part of a larger NIOSH research project. NIOSH was responsible for: 1) facilitating the risk assessment process known as Major Hazard Risk Assessment (MHRA), 2) documenting the risk assessment process, and 3) providing mine management with a written draft summary of the risk assessment process. The results of the risk assessment represent the thoughts and opinions of the individual risk assessment teams and should in no way be construed as an endorsement of the risk assessment output by NIOSH or the University of Pittsburgh.

Jan 1, 2009