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By Amanda Elioff

Success of the Gold Line Eastside Ex-tension rail tunnels in Los Angeles, CA has prompted the Los Angeles County Metropolitan Transportation Authority?s (Metro) planning new rail lines to include underground alternatives. The Westside Extension Transit Corridor alternatives include up to 27 km (17 miles) of subway to be constructed in soft ground. The routes will require construction in Los Angeles? ?potential methane zone,? which was not considered for subway construction until recently. Slurry face tunnel boring machines (TBM) will likely be specified.

Jan 1, 2009

By B. Leong, H. Joubert

Keywords: Pyrometallurgy, furnace, auxiliary equipment, copper slag launders Pyromet has designed copper launders for tapping slag. What makes Pyromet?s launder design innovative and safe is that it does not have any cooling water channels underneath the launder runner, whilst achieving effective cooling of the runner. If matte burn-throughs were to occur through the launder runner, the risk of damaging water channels and the risk of explosions are reduced. In addition, since the cooling water channels are not harmed, the launder is easily repairable and reusable. Pyromet makes use of Finite Element Analysis to optimize the launder geometry to ensure that sufficient energy is removed from the centre of the launder. Factors considered during the launder design include the suitability of the geometry to the client?s needs, experience from existing installations, and ease of fabrication. Pyromet goes so far as to develop procedures for fabricators to ensure that fabrication issues do not compromise the functionality of the launder. When launder orders are received by Pyromet, the entire fabrication process and the functioning of the launders during operations are monitored to ensure that the launder designs are continuously improving with every installation.

Jan 1, 2006

By Matters, R T, Coldham, Slee, J C, R J, Wallman

The Committee desires to thank the managers of the various mines along the line of lode for their hearty co-operation in its labours. It would also extend thanks to Messrs J C Moulden, Howchin, Twelvetrees, and the West Australian Geological Surveyfor various information; to Messrs J G Dreyer, S Pope, T Read, P Moncrieff, R Williams, and W J Rose for analyses; and to a number of local gentlemen for advice and help. Professor Skeats, of Melbourne University, gave much valued assistance in petrology, and Mr Herbert Lavers kindly undertook the study of the garnets.INTRODUCTIONThe famous Broken Hill lode is situated in a low range of hills, the Barrier Ranges, near the western border of New South Wales. It has been worked since 1884-fust for silver, then for silver and lead, and at present for lead, silver, and zinc...

Jan 1, 1910

By Nikolaos Petropoulos, Daniel Johansson, Håkan Schunnesson

The optimization of the explosive performance is of great importance since blasting is extensively used in civil projects and mining industry. An improved understanding of how the energy from the detonation of an explosive is transmitted to the surrounding rock mass is critical information for the proper selection of an explosive. Therefore, an extensive study was done on the influence of the blasthole diameter on the Velocity of Detonation (VoD) and the detonation front curvature. In this study, pure emulsion was tested in confined conditions to better simulate the behavior of the detonation of the explosive in rock mass conditions. A methodology is proposed for carrying out the evaluation of the explosive performance. The blasthole diameter of the samples varied from Ø 25 mm (0.98 in) up to Ø 65 mm (2.55 in). The confiner was a magnetic mortar cylindrical sample with mechanical properties similar to a rock mass. A streak camera and VoD probes were used to measure detonation front curvature and VoD. The data was analyzed and correlated with the physical parameters of the explosive. Additional to this, the data was further used to calibrate numerical models in LS-Dyna.

By Terry M. Tilley, Gregory P. Sherry

Purpose This is a unique project because the mining and tunneling industries have become highly mechanized and cannot normally accommodate a project where surface disturbance must be minimized or eliminated when there is less than 10 feet of ground cover. More traditional less mechanized methods must be employed and the skills and techniques for accomplishing the work have become all but non-existent. Therefore, this article highlights those areas of specialized skills and techniques. Methods The article will describe the design approach, the method(s) of ground support selected, the method(s) of excavation selected, the planning, scheduling and materials selection process. In addition, the article will describe the actual production characteristics and the results of the project. This approach will concentrate on productivities, adaptations to actual conditions and the quality of the end product. The design approach basically was to insure that the temporary support methods were adequate for the excavation and shoring stage of the project. The final concrete liner was designed using conventional structural design methods with the goal of constructing a tunnel that will last 100 years. The methods of support were spiling and variations of spiling in order to provide advance temporary ground support. In this project spiling is steel channel cantilevered and driven into the ground ahead of the working tunnel face which supports the ground allowing the face muck to be removed with overhead protection’. Conclusion This will be a discussion of the applicability of the methods. The actual performance of the excavation and shoring methods will also be evaluated. The final concrete liner completion results, the actual production rates and the conformance with budget and schedule will be addressed.

Jan 1, 2005

By F. M. L. Mulaudzi

Behaviour studies of metal dusting processes and associated filamentous carbon formation were undertaken on Alloys 600, 601, and 800 using a simulated metal dusting environment of 25C0-70H2-5H20 (vol.%) at 650°C. These samples were studied visually and by optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM-EDX) and x-ray diffraction (XRD). Visual examination and SEM surface observation showed that Alloy 800 suffered metal dusting attack at an early exposure reaction period. The coke deposit amounts increased significantly with reaction time from 168 hours to 336 hours in Alloys 600, 601, and 800. Alloy 800 showed pitting after 168 hours' exposure, and the degree of pitting increased after 336 hours. XRD showed all these alloys had a common austenitic phase, with Alloy 800 also having ferritic metal particles. Alloy 800 after 168 hours' exposure had a complex phase mixture on the surface, consisting of ferritic Fe and austenitic FeNi phases. For coke deposit, there were also Fe304, Fe3C and graphitic carbon. The existence of Fe, Ni, and Cr metal particles, and also graphitic carbon in coke deposits, was confirmed by EDX analyses.

Jan 1, 2013

An effective electrowinning process in hydrometallurgical industry requires fluoride levels in the base metal solution to be less than 10 mg/l. Selective removal of the fluoride ions from base solution is thus desired, if fluoride was added to control calcium and magnesium in the circuit. Consequently, adsorption of fluoride onto activated alumina was studied in a batch and a column set-up. The effects of base metal solution pH, temperature, initial concentration and flow rate on activated alumina performance were investigated in either a batch or column configuration. A two-level factorial experimental design was implemented in studying column dynamics. Results demonstrate that activated alumina is an effective adsorbent for selective removal of fluoride from base solution. In the batch operation, fluoride was removed to values below the maximum allowable concentration (10 mg/[l]) when pH was = 8. In the column adsorption step at 55°C and 600mg/[l] initial concentration, up to 16 bed volumes were processed before breakthrough level was reached. Desorption step using 1% sodium hydroxide solution achieved an elution of 8 bed volumes. The activated alumina (AA) had a capacity of 8.65 gF/[l]AA at the 10mgF/[l] fluoride breakthrough level during the column adsorption test. Keywords: Fluoride; activated alumina; adsorption; recovery; regeneration.

Jan 1, 2009

By Bruno Gemmi

The objective of the ? 200 million ($280 million) project Parma Railways Station-Urban Transformation was the reconnection of the North and South parts of the town by constructing an 80 m (250 ft) wide sunken artery passing under the four double railway tracks of the station without any impact on train traffic. The site of the project, adjacent to the Parma River, presented water seepage problems at any excavation depth. The use of conventional large diameter bored pile machinery was not allowed by the Railway Authority because equipment dimension and construction phases do not comply with train traffic safety regulations. Foundations for the bypass were thus constructed by minipiles nested into jet-grouted soil using machinery operating within the existing head room and at a safe distance from the tracks. Jet-grouting treatment reached depths of 25 to 28 m (80 to 90 ft) from tracks? grade and embedded minipile-heads were terminated at 2 to 3 m (6.6 to 10 ft) below grade. Load tests on minipiles were pushed to failure. Failure occurred at a 240 t (265 t) load without breakage of the bond between the jet grouted soil and the minipiles. A 0.93 MPa (135 psi) shear resistance ??? between minipile steel casing and the jet grouted soil was measured prior to the failure of the steel casings. Overall measured foundation settlements were well within expected values and were considered insignificant.

Jan 1, 2011

Visit to the Modderfontein factory of A. E. & C. I. Ltd 23rd November, 1972 A full programme was arranged to suit both the mining and metallurgical sections of the Institute. After refreshments were taken and visitors welcomed by the factory management we were split into two groups, viz metallurgical and mining. Book review Stress-relief Heat Treatment of Vanadium Steels by Or G. O. Joy and Or A. M. Sage (21 pp, 77 references).

The current genesis of pisolites and channel iron deposits (CID) has been defined in a way that presents CID as unique in the world. The published material on detrital pisolites mostly details the West Australian CID; most other global occurrences of iron-rich pisolites would seem to have an in situ genesis. An alternate theory for the origin of the Hamersley CID is suggested, involving an older greensand protore derived from volcanic ash and deposited on a glaciated Hamersley surface. This paper presents the author's observations, sampling and mapping after several years study and exploration for pisolites and CID in WA and in some locations overseas. It is not what one would call scientifically complete, and possibly asks more questions than it answers, but it is presented as a point for discussion.

Jan 1, 2009

By Baker G

The detailed mineral composition of the lead-zinc ores at Captain's Flat was first studied in 1942 (Edwards, 1943).At that time the workings did not extend far below the 750ft. level. Since then development has been extended to the 1,390ft. level, and -at the request of the management of Lake George Mines Ltd., an examination of the ore from the deeper levels has been made as part of the research programme of the Mineragraphic Section of the Commonwealth Scientific and Industrial Research Organization.This account is. based on that examination (Mineragraphic Rept. No. ,537, C.S.I.R.O.)GENERAL GEOLOGYThe geology of the Lake George Mines has been described briefly in The Geology of Australian Ore Deposits (1953), and in much greater detail in an unpublished report by K. Glasson (1952). The area consists of fossiliferous Upper Ordovician sediments overlain by volcanics (Kohinoor VoJcanics), and by fossiliferous Silurian sediments. The volcanies comprise a series of· flows ranging in' composition from dacite to rhyolite, with interbedded tuft's and shale lenses.The region has been strongly folded. The regional strike is from 340° to 355°, and dips are from 75°W. to 75°E, A major syncline, pitching 200 N., occupies the centre of the area. The Kohinoor Volcanic'l outcrop as two bands which represent the east and west limbs of this syncline.The Volcanks in the western limb, with whIch the orebodies are associated, are more strongly sheared than those in the eastern limb.

Jan 1, 1953

By Kanchan K. Sen

The North Shore Connector (NSC) project will extend the Allegheny County Port Authority?s Light Rail Transit System from downtown Pittsburgh below the Allegheny River to the North Shore via twin bore tunnels. Jet grouting, diaphragm walls, and soil mixing were selected as cost-effective technically viable ground improvement and support of excavation techniques. Jet grouting was specified to provide break-out (egress) and break-in (ingress) block sections at the tunnel boring machine (TBM) launching and receiving pits. Jet grout treatment was also used adjacent to buildings with shallow foundations and below retaining walls along the tunnel alignment. A new method for measuring jet grout column diameter based on electrical resistivity was employed on the project. New equipment was introduced in the U.S for constructing soil mix temporary support of excavation using a soil-mix technique termed Cutter Soil Mixing (CSM) due to the use of two vertical cutting wheels that have evolved from diaphragm wall trench cutter technology. The system allows for continuous water tight soil mix panel construction including steel beams. This paper highlights some applications of jet grouting and various support of excavation systems (e.g. slurry walls, cement bentonite walls and CSM walls), including new innovative techniques (e.g. Cyljet and CSM) used under the constraints of an urban environment.

Jan 1, 2010

The 1965 Lignite Symposium, the Louth in a series and the third sponsored by the University of North Dakota and the Bureau of Mines, was held at Bismarck, N. Dak., on April 29-30, 1963. These symposia provide a forum for those interested in the technology and utilization of solid fuels, especially lignitic coals. As part of the meeting, a 200-mile field trip was taken including; inspection of (1) the 200-megawatt, pulverized lignit-fired Leland Olds plant of Basin Electric Power Cooperative, under construction near Stanton, N. Dak.; (2) the site of the Glunharold mine of the Truax-Traer Coal Co., Division of Consolidation Coal Co., where a wheel excavator was being assembled; (3) the operating Beulah mine of Knife River Coal Mining Co., subsidiary of Montana-Dakota Utilities Co., near Beulah, N. Dak.; and (4) the 400-megawatt, hydroelectric Garrison Dam powerplant, near Garrison, N. Dak.

Jan 1, 1966

By A. M. Tunstall, N. Djordjevic, H. A. Villalobos

The damage zone behind a typical smooth-wall blast in the open pit was assessed by visually examining diamond drill core to identify blast-induced cracking, mapping core rock quality designations to identify changes in fracture frequency and conducting uphole seismic testing to determine changes in rock mass characteristics. The results from the three techniques show reasonable correlation. They suggest that major damage, in the form of fracturing of intact rock, occurs at least 7 m behind the smooth-wall blast and significant damage, in the form of opening and extension of calcite-filled fractures, at least 12 m from the blast. At greater distances the dominant damage mechanism is the loosening of existent joints within the rock mass. In the trachytes at El Soldado these damage mechanisms correspond to peak particle velocities of 2 000, 900 and 500 mm/s respectively

Jun 19, 1905

By Khamis Y. Haramy

Quality assurance and quality control of drilled shafts has become a concern due to difficulties in accurately locating construction anomalies and determining load bearing capacity of defected drilled shafts. Various non-destructive evaluation techniques have been developed to estimate the integrity of the concrete in drilled shafts. While these techniques have been widely accepted, variables and unknowns can affect the measurement results. Results are typically difficult to interpret, leading to unnecessary construction delays and possible litigation over shaft integrity. In addition, influences of surrounding ground materials, stress states under different load conditions, and crack and residual stress development during concrete curing further complicate determination of shaft performance. This paper focuses on the evaluation of load bearing capacity of defected drilled shafts under various conditions by numerical analysis and modeling.

Jan 1, 2007

By John R. Wolosick

MACROPILES are defined as ultra-high-capacity micropiles, with working loads in excess of 250 tons. The piles are typically 9-5/8 to 24 inch (244 to 610 mm) outside diameter. They are drilled and grouted in place, with either large diameter steel bars and/or steel pipe reinforcement. The piles are typically tested to twice the working load. Piles with working capacities of up to 500 tons and tested to 1000 tons have been installed. The paper discusses MACROPILE design philosophy, construction techniques, and two case histories where this innovative foundation system has been installed. Macropiles are descended from micropile technology pioneered in the early 1950s by Fernando Lizzi of Italy.

Jan 1, 2006

By Robert H. Peters

This report presents a literature review conducted by the U.S. Bureau of Mines. The review summarizes what has been learned from the large volume of empirical studies on the effectiveness of eight types of interventions intended to increase organizational effectiveness via in the management of human resources. The interventions concern the following: recruitment, selection, training, objective feedback, goal setting, reward systems, participative management practices and organization development. Although many of these interventions appear to have the potential for improving the safety and efficiency of mining operations, it does not appear that they are being widely used. Examples are given of the successful use of a few of these interventions at mining operations. An analysis of the relationship between coal mine productivity and safety is also presented. This analysis generally supports the view that good safety performance and high productivity are NOT incompatible goals. In fact, safe mines also tend to be more productive and vice versa.

Jan 1, 1992

By M. L. Tucker, William H. Langer

Many countries, provinces, territories and states in the European Union, Australia, Canada, the United States and elsewhere have begun implementing sustainability programs. Most of those programs, however, stop short of sustainable management of aggregate resources. Sustainable practices do not always have to be conducted under the title of sustainability. This case study describes how Lafarge implemented the principles of sustainability even though there was an absence of existing local government policies or procedures addressing sustainable resource management. Jefferson County is one of three counties in the six-county Denver, CO, region that has potentially available sources of crushed stone. Crushed stone comprises 30percent of the aggregate produced in the area. And it plays a major role in regional aggregate resource needs. Jefferson County is home to four of the five crushed stone operations in the Denver region. Lafarge operates one of those four quarries.

Jan 1, 2004

By Michael J. Beus

This Bureau of Mines report describes a tunnel stress relaxation gage (TSR) developed to measure initial radial displacement around full-sized underground openings. The TSR technique was shown to be a valid concept in previous field verification tests. Sensitivity has been improved by employing a titanium alloy cantilever in the transducer head, which also permits a deeper sensor location. Use of improved fabrication methods such as stainless steel bellows and sputtering techniques and use of an environmental chamber for testing greatly increased overall reliability. A miniature data acquisition system (DAS) was interfaced directly to the transducer for increased versatility and containment entirely within a borehole. The present TSR system is suitable for use around full-size underground excavations, particularly machine-bored openings. Field evaluation of the improved instrumentation verified the design goals.

Jan 1, 1978

By James V. Errico

On October 1, 1993 the regulations for assessing and cleaning up contaminated soil and groundwater in the Commonwealth of Massachusetts were revised. These new regulations, known as the Massachusetts Contingency Plan (MCP) 310 CMR 40.0000, were developed to keep routine releases out of the regulatory system and rely on private parties to handle most releases without Department of Environmental Protection (DEP) oversight. An integral part of the new MCP is the Licensed Site Professional (LSP). An LSP is required to handle activities and render opinions once a site enters the MCP. These regulations must be adhered to where ever a release has occurred, including construction sites. A brief overview of the new MCP is given below; see attached MCP Flowchart for graphical summary. Entering the MCP Process A release of oil or hazardous material (OHM) to the soil or groundwater above applicable reportable quantities (RQ's) or reportable concentrations (RC's) will require notification to the DEP and compliance with applicable provisions of the MCP. RQ's and RC's are listed in the MCP (310 CMR 40.1600) for most compounds that are typically encountered. For each compound there are two RC's for soil (S-1 and S-2) and two for groundwater (GW-1 and GW-2). The S-1 and GW-1 RC's apply to sites that are environmentally more sensitive, as a result they are lower than the S-2 and GW-2 RC's.

Jan 1, 1994