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By Bruce McKinstry

INTRODUCTION In June of 1992, the Bureau of Reclamation, United States Department of the Interior, awarded the contract for construction of the Sixth Water Aqueduct to the Fedrick-Redpath Joint Venture. This aqueduct, a segment of the Diamond Fork Power System, Central Utah Project, diverts water from Strawberry Reservoir into Sixth Water Creek and, when complete, will replace the old Strawberry Tunnel which was driven in the early 1900's. The new aqueduct is being built primarily as a result of deterioration of the old tunnel, but will also have a higher capacity and more positive control than the old tunnel as well as the capability to incorporate a turbine into the system at a later date. The Fedrick-Redpath Joint Venture is comprised of C.R. Fedrick, Inc. of Novato, California and J.S. Redpath Corporation of Tempe, Arizona. Fedrick, with its experience in pipelines and heavy construction, will construct the 4200 ft surface pipeline and flow control structure; Redpath, the managing partner, performed the underground work consisting of a 600 ft vertical shaft and 3300 ft tunnel. The project is located in the Uintah National Forest, approximately 20 miles east of Provo, Utah at a mean elevation of 7000 feet above sea level.

Jan 1, 1995

By A. G. Belova

Conversion of coal into high-value gases via gasification offers significant pollution reduction and efficiency improvement benefits associated with controlled combustion of clean gases for power generation. However, current gasification-based electricity production technologies, such as IGCC do not address carbon dioxide emissions. The focus of the study is CO2 capture on CaO prior to combustion of coal-derived gases. To overcome kinetic and stability limitations associated with its utilization, CaO is distributed on high-surface area -Al2O3 and supported on a ceramic honey-comb monolith. The proposed method allows for efficient capture of CO2 from a gas mixture, as studied in a flow-through reactor system. This novel method of CO2 capture is used here to argue for pre-combustion capture of CO2 in coal gasification-based power plants. When CaO is present during the steam reforming of coal gasification gases, continuous withdrawal of CO2 from the system provides for higher yields of reforming products (hydrogen gas) by influencing the thermodynamic equilibrium of the entire system.

Jan 1, 2009

By Pieter Barendsen, Olivier Dubugnon

INTRODUCTION There are three fronts on which development efforts are being concentrated to extend the application domain of Tunnel Boring Machines (TBM), which is potentially very large - Assessment of a reliable prediction method, including machine-rock interaction and geological characterisation, so that the boring system can be designed properly and the costs remain in the predicted range for each given tunnel project. - Development of lighter, more flexible and more controllable machines to be applied in shorter, deeper tunnels or roadways, such as required in mining. - Reduction of cutter and machine costs when excavating hard rocks or difficult grounds, in developing improved tool materials, cutting geometries and tunnelling systems. The above three lines of development have a common, critical requirement: to have a reliable set of design rules to optimize the machine specifications from the knowledge of rock and geological parameters and working requirements. This optimization can only be done if a model sufficiently sophisticated is made available, able to take into account the numerous factors influencing the TBM advance , and being interactive enough to achieve the optimization.

Jan 1, 1985

By William R. Groseclose, Kenneth D. Schoeman

The Buckskin Mountains Tunnel is a key link in the Bureau of Reclamation's Central Arizona Project. The 22-foot (6.7-m) diameter tunnel is being bored in a north-northwesterly direction through volcanic rock near Lake Havasu in western Arizona. The 6.9-mile (11-km) conveyance tunnel will carry up to 3,000 cfs (85 cu m per sec) of water through the Buckskin Mountains as part of the Granite Reef Aqueduct. The water for the project will be drawn from Lake Havasu behind Parker Dam on the Colorado River and pumped some 800 feet (244 m) above the lake to the inlet portal of the free flow tunnel where it begins its 190-mile (300-km) journey to Phoenix, Arizona, and beyond into Orme Reservoir (figure 1). Precast concrete segments are being used as a single system initial support and final lining in the tunnel being excavated by a tunnel boring machine specially designed and built for the job by The Robbins Company. J. F. Shea Company, Inc., of Walnut, California, is constructing the tunnel for the Bureau of Reclamation.

Jan 1, 1976

By D. A. Newman

A longwall chain pillar is comprised of two distinct zones, a solid elastic core enclosed by an exterior of failed or yielded coal. For the purpose of pillar design, the ability to delineate the extent of pillar yielding and correlate the yielding with the applied pillar load is of fundamental importance. A study was initiated on a longwall section of a West Virginia mine to: (1) delineate the location of the elastic core-yield zone boundary, (2) examine the stress distribution within the pillar, and (3) quantify pillar stability as the longwall face retreated toward an instrumented pillar. A US Bureau of Mines sonic velocity probe was used in conjunction with vibrating wire stress meters to define the elastic core-yield zone boundary and the migration of vertical stress toward the pillar core. The extent of the yield zone as determined by field results is compared with the extent of the failed zone as predicted using a series of equations developed by Wilson.

Jan 1, 1988

By W. Setzepfandt, J. Henneke

PREFACE Debris disposal can very often be a severe problem and major restriction on tunnel boring projects, especially for small diameter tunnels and in underground mines. Hydraulic transport could provide a suitable solution. Investigations have therefore been made in connection with a full-scale project of 4.8 km length and 2,3 m diameter, to obtain the required technical and economical data for planning an optimized transport system, e.g. for a tunnel boring drivage of 6 - 7 m diameter in underground coal mines. INTRODUCTION The Radau-Tunnel, chosen for the investigations, has been designed for transferring flood peaks between the rivers Radau and Grosse Romke in the Harz-Mountain of Lower Saxony. A DEMAG TVM 20/23 H tunnel boring machine was used to drive the tunnel on a rising gradient of 0,53 %. The rock consisted of shale and hornblende (55 %), granite (15 %), diabase (15 %), chert (8 %) and gabbro (7 %). The project has been sponsored by the Federal Ministry of Research and Technology.

Jan 1, 1981

By Robert L. Bates

An industrial mineral, says the Glossary of Geology, is "any rock, mineral, or other naturally occurring substance of economic value, exclusive of metallic ores, mineral fuels, and gemstones; one of the nonmetallics." Probably most geologists and engineers would accept this simple and straightforward definition, at least as a general statement. On analysis, however, certain anomalies crop up. For example, what is metallic and what is nonmetallic? Bauxite and ilmenite certainly qualify as metallic ores, but both are also raw materials of important nonmetallic substances; hence they are included in this book. Another anomaly is that, by common consent, the term industrial minerals may include not only rocks and minerals but also certain manufactured products, such as cement and lime, and even mixed groups of natural and artificial products, such as abrasives and refractories. Thus the central realm of the industrial minerals is clear enough, but its boundaries tend to be indefinable. Since a definition that allowed for every irregularity in the outer fringes would be excessively unwieldy, the one quoted above may be considered satisfactory. The expression industrial minerals is commonly equated with nonmetallics, and with the somewhat more precise phrase industrial minerals and rocks as in the title of this book.

Jan 1, 1994

By S. Ash

Murray mine was one of the first Mechanized cut and fill underground gold operations in Northern Nevada. At the end of 2002 mine production began to decline and Murray entered a phase of remnant mining and began preparations to close down. The remaining mining took place along the ore waste boundary, in previously condemned areas, and in highly challenging ground conditions. To remain economically viable new techniques were implemented in operations, geology, engineering, and rock mechanics. These improvements pushed the edge of known and accepted mining practices and have allowed Murray to remain in operation today. History The Murray mine is located on the Jerritt Canyon property, which is located 45 miles north of Elko, NV in the Independence mountain range. Mining operations started at Jerritt Canyon in 1980 out of several open pits. In 1993 underground mining began in conjunction with a decline of surface mining operations. The transition from surface mining to underground mining moved the property into a new era. At the time there were limited examples of successful underground operations in the area from which to draw experience. Several mining methods were attempted with varying degrees of success and underhand cut and fill proved to be the most effective method. To date Murray has mined 1.2 million ounces at an average grade of .335 OPT utilizing this mining method.

Jan 1, 2006

By A. F. Klebanov, K. N. Trubetskoy, M. Yu Khoudine, V. L. Postnikov

The information system of monitoring of mine receive layouts is being created In the "ROSUGOL" Company for the prompt analysis of the state-of-the-art of mining operations at under- ground and open cast mines of the Company, rapid and effective decision-making and elaboration of recommendations on the basic directions of enterprise development. The data bank storing the digital mapping and attributive information describing the actual background of mining operations at the enterprises of the Company is the core of the system. The Oracle database management system and the ARC1 INFO geographic information system have been chosen as basic software packages for the Project realisation. The updating of the information will be performed on a regular basis via the transmission of actual digital data on under- ground and open cast mine layouts In ARCIINFO conversion to the central office of the "ROSUGOL" in Moscow. Centralised storage of digital mapping and attributive data, database administration and navigation is effected with the Oracle software package. Access to the data in the operation mode with an interactive display map will be effected with the use of the local computer net of the "ROSUGOL."

Jan 1, 1996

By O. A. Bascur

The problem of setting the proper control objectives and/or having several objectives to be met in the implementation of grinding control strategies can be resolved. The design and implementation of a distributed control system for safe operation of a grinding circuit while maximizing profit is presented. An optimal recovery through- put target for a desired grind is accomplished by advanced control strategies at the DCS level. A mill load constraint control technique provides stable operation with a substantial increase in throughput, while the desired grind index is maintained by an inferential grind control technique without using a particle size analyzer. The integration of crushing/grinding and flotation in the overall design was the key to the success of the project. This synergistic effect was obtained by implementing a computer plant management system in the concentrator. The overall/philosophy was to keep the implementation simple while using new technology creatively.

Jan 1, 1991

By B. J. Arnold

A coal's size distribution clay content and moisture content can affect its handling behavior. But the combined effects of these properties and the effects of other properties are not known. Research underway at CQ Inc.'s (formerly EPRI's) Coal Quality Development Center (CQDC) and at Iowa State University (ISU) will answer these questions as part of a four year project to develop a coal handleability index for utilities to use when specifying coals. This paper will present preliminary data from the first year of the project, which focused on obtaining data on the chemical and physical properties of carious coals and their measured handling properties. Additionally, size, ash and moisture analyses and shear test data for several coals used at one power plant will be presented along with correlations between these physical and chemical properties and the measured handling properties. These data lead to the conclusion that while moisture content is the most important variable, the amount of -44 µm (-325 mesh) coal fines is a significant factor in determining coal handling behavior.

Jan 1, 1992

By Leonard W. Postregna

Prior to January, 1986, the city of Austin, Texas was on notice by the Federal Government's Environmental Protection Agency and the Texas Water Commission, that they were illegally polluting the Colorado River. The wastewater facilities presently in use in South Austin were inadequate to handle the vastly increasing population. The city of Austin, Texas hired Parsons Brinckerhoff Quade and Douglas, Inc. and Dannenbaum Engineering Corporation to design and supervise the construction of an update to their existing system to alleviate this problem. A major criterion handed down to the Designer and Contractor was that the system had to be completed within a two year time frame. The biggest link to the entire design was a tunnel project consisting of 43,000 linear feet (13,106 m) of tunnel, eight feet (2.44 m) in diameter with connecting structures tying into existing and future facilities. The project was awarded to S. A. Healy Construction Company of McCook, Illinois with a low bid of $24,755,000.00. This article summarizes the techniques used in the construction of this tunnel project.

Jan 1, 1989

By C. P. Mangelsdorf

Introduction During the 13 years since C. C. White introduced the Birmingham roof truss there has been a revolution in permanent roof support technology. While not all of the emerging concepts have their origins in the truss-resin bolting is a prime example - the combinations and permutations of devices presently available to the underground mining industry reflect a well-spring of creative activity. The purpose of this report is to chronicle a number of roof support system that have same physical similarity to the Birmingham truss, and to report on their application. Definitions The application of the tern "truss" to the device developed by White of the Birmingham Bolt Company in 1967 may be derived from the classical technique of stifwood, by the attachment of an underslung, sometimes pretensioned metal strap, rod or cable. If the beam is separated from the reinforcement by a single block or vertical post it is called a "King's Post Truss". If two equally spaced blocks or posts are used it is referred to as "Queen's Post". When the immediate roof of a mine is visualized as a beam, the Birmingham device completes a structure resembling this latter form.

Jan 1, 1982

By S. Frimpong, N. Demirel

Overburden excavation is an integral component of the surface mine production chain. The walking dragline is the most economic production equipment for overburden excavation in strip mining. Draglines are capital intensive, and thus, investments in multiple units severely impact the economic viability of projects. The use of few dragline units results in highly concentrated production focus, which must be efficiently managed to derive the potential economic benefits. Efficient use of draglines requires a thorough knowledge of the powered functions, the 3D rotational and translational motions and machine-formation interactions within the operating environment. Dragline kinematics and dynamics are required to understand and characterize machine performance and efficiency. In order to sustain the high productivity in difficult operating conditions, the dynamics of the dragline must be modeled and analyzed based on comprehensive kinematics. This paper investigates the planar kinematics of the front-end assembly and its interactions with the formation during excavation using the “Vector Loop Analysis” formulation with comprehensive simulation modeling in MATLAB Simulink. The kinematic models are used to examine the translational, rotational and angular displacement, velocity and acceleration components of the dragline front-end assembly along defined bucket trajectories during excavation. The results are the precursors for comprehensive modeling to examine the load deformation, torque requirements and dragline stress loading profiles for improving machine health and longevity.

Jan 1, 2006

By T. S. Golosinski

Most of the 154 t (170 st) truck fleets that were predominant in large surface mines in the 1970s and 1980s are approaching the end of their economic life. One replacement option considered by mine operators is a change to the 2 18 t (240 st) trucks. A comparison of load capacities between the 1.54 t (170 st) and the 2 18 t (240 st) trucks indicates a large productivity advantage in favor of the 218 t (240 st) trucks. This advantage, however, is often reduced by a number of site-specific factors. Therefore, a careful evaluation is required to define the actual benefit of changing to the large trucks. This article discusses some important factors that have an impact on truck size selection, based on several different studies. 218 t (240 st) trucks The 2 18 t (240 st) rear dump trucks were first introduced for surface mine service almost 10 years ago. However, it is only during the last few years that this equipment has gained acceptance in the surface mining industry. About 250 units were employed in surface mines worldwide at the beginning of 1992, and further purchase commitments are being made. Encouraged by the mining industry’s interest, all major off-highway mining truck manufacturers now offer 218 t (240 st) models (Table 1). At present, the existing 218 t (240 st) truck fleets are dominated by electric drive trucks. However, recent introduction of a 2 18 t (240 st) mechanical drive truck rounds out the development of this truck size.

Jan 1, 1992

By Rudolf Greuer, Gerald Jalkanen, Huann-Sheng Chen

A short cut is presented where the average grade above a primary grade cutoff and its associated byproduct grade(s) are estimated by screening the primary and byproduct grades. For the primary variable, choose samples whose grades are above a cutoff of interest. Compute variograms for the subset of the primary variable. Then using this variogram, krige the blocks of interest only using the samples whose grades are above the cutoff. The next step is to screen byproduct grades by choosing byproduct samples whose associated primary grades are above the cutoff of interest. Next compute variograms for this subset of byproduct samples. Then using this variogram, krige the blocks of interest using byproduct sample grades whose associated primary sample grades are above the cutoff of interest. The results are the average grade above a primary cutoff for both the primary and the associated byproduct variables. Using two simulated primary and reference data sets a case study resulted in the screening krigings performing better than the indicator kriging approach in the first case study. A second case study had mixed results with the primary indicator approach performing better than the primary screened approach. The byproduct screened approach performed better than the byproduct indicator approach.

Jan 1, 2002

By Y. M. Jiang

From underground instrumentation data and from direct observation of longwall panels, it was demonstrated that growth of the main-roof overhang causes an extremely high roof weighting on the face supports. This can result in catastrophic effects on the supports when the roof-weighting intensity far exceeds the support capacity. In this paper, a comprehensive study was conducted on the characteristics of main-roof breakage and its effects on shields at different locations along the face. The study was based on monitored shield data, theoretical analysis and finite element analysis. With the help of theoretical analysis and numerical modeling, stress distribution and redistribution in the main roof were analyzed to define the main-roof failure modes and to understand the maximum roof-weighting intensity imposed on the shields. From this study, it was found that the effects of main-roof breakage on shields are chiefly related to the shield's initial-setting condition and to the final failure mode of the main roof.

Jan 1, 1996

By Owen E. Owens

INTRODUCTION This paper deals with the main components in exploring for and developing a gold ore deposit. It addresses geology, exploration drilling, ore reserves, and evaluation criteria in an integrated manner to present an overall picture. Gold forms such a small component of a gold ore body, that particular care should be taken in dealing with the data from a developing deposit. The paper lists the main gold ore deposit types and their character. Their differences, as well as differences to other types of ore deposits, are important to understanding exploration approaches, and problems of ore reserve definition. Gold exploration has enjoyed a great boom in recent years. Many new ore deposits have been developed but experience shows that definition of gold is not a simple straight forward process and this outline attempts to point out some of the important aspects of ore reserve definition including some pitfalls. GOLD DEPOSIT TYPES The Witwatersrand deposits in South Africa produce about 50% of the world's gold. The gold occurs as fine grains in thin beds within gently dipping quartz pebble fan conglomerates usually with associated pyrite grains. It is characterized by rather uniform distribution of gold along thin layers within the conglomerate.

Jan 1, 1988

By J. D. Miller, C. L. Lin

Liberation of valuable minerals during size reduction is an important aspect of mineral processing technology. In practice, most quantitative information on liberation is based on the application of stereological theorems for the analysis of image data from two-dimensional polished sections. On this basis an estimate of the volumetric grade distribution is made. Recently, a new method based on cone-beam xray microtomography has been used for direct determination of the three-dimensional liberation spectrum of multiphase particles 100 microns in size or less. Preliminary results for a packed bed of particles indicate that high spatial resolution (approximately 15 microns) and the direct processing of raw volumetric data are two important benefits offered by this new method. Three dimensional liberation analysis by microtomography provides an excellent opportunity to overcome many of the limitations of currently used polished section techniques. For example, detailed textural information is provided. Of course microtomography provides an independent method to verify current procedures used for analysis and transformation of polished section data into an estimate of the volumetric grade distribution. More important, however, is the possibility that this method could be developed as a routine procedure for liberation analysis in the 21st century.

Jan 1, 1997

By W. de Moura, R. Fueyo, M. M. Botz, J. C. Scola

The Cerro Vanguardia mine is an AngloGold Limited operation in southern Argentina that includes multiple open pits and a hybrid Merrill-Crowe and CIL circuit to recover gold and silver from oxide ore. Operations were commissioned at the site in 1998, which included a plant in the metallurgical circuit to recover cyanide from mill tailings. The cyanide recovery plant was initially configured to process tailings slurry and achieved greater than 90% cyanide recovery from tailings containing about 600 to 800 mg/L WAD cyanide (as CN). The cyanide recovery circuit was operated in this manner for approximately eight months, during which time the consumption of sulphuric acid and sodium hydroxide was relatively high, leading to high rates of scale formation in the acidification tank and stripping towers. In July 1999, several piping changes were made in the cyanide recovery system to permit its operation with clear solution, which reduced the sulphuric acid consumption and eliminated scale formation in process equipment. The cyanide recovery system currently operates with a two-stage counter-current decantation (CCD) circuit which provides clear solution for processing in the cyanide recovery plant. The cyanide recovery efficiency now averages about 90% to 92% from solution containing about 350 mg/L WAD cyanide (as CN). Recovered sodium cyanide now accounts for about two-thirds of the total cyanide added to the leaching circuit. This paper presents a description of the cyanide recovery plant and details regarding its current operating efficiency.

Jan 1, 2004