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By Felipe De Lucio Pezet

El presente texto es un recuento de acontecimientos importantes ocurridos en el distrito minero de Morococha desde la época precolombina hasta 1940, de forma que contribuya al desarrollo de la historia minera del Perú.

Nov 1, 1979

Copper cathode and Uranium Oxide production at WMC (Olympic Dam Corporation) Pty. Ltd. involves processing leach liquors through a copper solvent extraction plant followed by a uranium solvent extraction plant. This paper discusses the processing problems, metallurgical testwork and circuit changes made due to contamination of amine in the oxime circuit and vice versa.

Jan 1, 1996

By Brenton Cook, Nate Long, Larry Applegate, Aaron K. McCain

"The Northgate Link Extension project is the third phase of the Sound Transit master plan to extend light rail throughout the greater Seattle metropolitan area. When completed, the Northgate Link Extension will extend the existing light rail system north by about 7 km (4.3 miles) from the University of Washington to the Northgate neighborhood. A general overview of the project alignment is provided as Fig. 1. The project was funded by a combination of federal grants and allocations from local taxes. The general contractor on the project was JCM Northlink LLC (JCM), a joint venture between Jay Dee Contractors, Frank Coluccio Construction Company and Michels Corp. SoilFreeze, Inc. was retained as a subcontractor to provide ground freezing design and construction services.The project involved the construction of two parallel 5.5-m, 25-cm (18-ft, 10-in.) (inside) diameter tunnels using earth pressure balance (EPB) tunnel boring machines (TBM) and precast segmental concrete tunnel liners. The two tunnels maintained roughly the same elevation along the alignment and were spaced roughly 12 m (40 ft) apart (centerline to centerline). A total of 23 cross-passages connecting the two tunnels were included at approximate 244-m (800-ft) intervals. Cross passage excavations were elliptical in shape with dimensions of approximately 5.6 m (18.5 ft) in height and 5.3 m (17 ft) in width. The cross-passages were 5.8 to 6.1 m (19 to 20 ft) long as measured between the exterior of the tunnels at springline elevation. Cross passages were intentionally located directly beneath public right-of-ways thus avoiding buildings. Many of the cross passages were located beneath narrow roads in residential neighborhoods with mature vegetation, existing utility structures and piping and limited parking areas. Excavation and support for each cross passage was completed using the sequential excavation method (SEM).The subsurface soil and ground water conditions at the cross-passage locations were described in the Northgate Link Geotechnical Baseline Report (GBR) prepared by Jacobs Associates and the Northgate Link Geotechnical Data Report (GDR) prepared by Shannon and Wilson, Inc. Soils along the project alignment were glacially overridden and characterized as very dense or hard. Subsurface soils consisted of cohesionless sand and gravel (CSG), cohesionless silt and fine sand (CSF), cohesive clay and silt (CCS) and till and till-like deposits (TLD)."

Dec 1, 2018

By Ethan Steward, Robert Eades, Kyle Perry

Shock tubes, either gas or explosively driven, are often used for physical modeling of free field explosions or arena testing. The use of shock tubes often requires less setup time of subjects and smaller driving forces to create pressure versus time waveforms similar to that of arena testing. However, the effects of the shock tube cross sectional geometry on waveform properties is uncertain while free field explosion wave propagation and estimation is well studied.

Jan 1, 2018

By Linda K. Killoran

The U.S. Bureau of Mines has developed a prototype cross well acoustic logging system and complementary tomographic image reconstruction software for the detection and delineation of abandoned underground mines and associated subsidence failure in relatively shallow environments. The logging system uses a piezoelectric, cylindrical bender as an acoustic source. A triaxial accelerometer assembly, designed to be rigidly locked in the borehole, is the receiver portion of the logging system. Both the source and receiver probes operate at high frequencies, thus providing short wavelengths capable of resolving small features in most rock types. A modified van with a dual-drum wireline winch, 4-channel data acquisition system, power amplifiers, and waveform generator supports field operation of the logging system. A field study was conducted at a test site in San Antonio, Texas, to demonstrate the cross well acoustic logging system. The underlying rock at the test site is similar to stratified sediments in coal measures. First¬arrival travel times were interpreted by tomographic reconstruction of the velocity field in the two-dimensional cross section between the source and receiver boreholes. The resulting image correlates well with geological borehole logging data for the test site.

Jan 1, 1992

The U.S. Bureau of Mines has developed a prototype cross well acoustic logging system and complementary tomogr`aphic image reconstruction software for the detection and delineation of abandoned underground mines and associated subsidence failure in relatively shallow environments. The logging system uses a piezoelectric, cylindrical bender as an acoustic source. A triaxial accelerometer assembly, designed to be rigidly locked in the borehole, is the receiver portion of the logging system. Both the source and receiver probes operate at high frequencies, thus providing short wavelengths capable of resolving small features in most rock types. A modified van with a dual-drum wireline winch, 4-channel data acquisition system, power amplifiers, and waveform generator supports field operation of the logging system. A field study was conducted at a test site in San Antonio, Texas, to demonstrate the cross well acoustic logging system. The underlying rock at the test site is similar to stratified sediments in coal measures. First- arrival travel times were interpreted by tomographic reconstruction of the velocity field in the two-dimensional cross section between the source and receiver boreholes. The resulting image correlates well with geological borehole logging data for the test site.

Jan 1, 1992

By C. R. Tinsley

Investment activity in the Pacific Rim of Fire has seen a phenomenal surge from epithermal gold exploration. Individual countries are attractive because of lower up-front minerals lease costs (US, Canada), better geological prospectivity (Chile, Indonesia), or cheaper equities (Australia). Since the October 1987 stock-market crash, large companies are shedding minority joint venture interests to focus on core businesses. Some vertical integration is evident in Japanese coal investments in the Pacific Rim. This paper does not cover the aluminum industry oligopoly which is multi-national in character nor does it cover the many Canada to US minerals investments. It will be interesting to see if the new US-Canadian free-trade treaty will reverse that investment flow.

Jan 1, 1990

By R. J. Lytle

INTRODUCTION Prior to excavation in soil and rock, it is useful to know the subsurface structure. This is important information both for safety and for equipment scheduling reasons. It is useful to know whether parts of the subsurface might be potentially troublesome or of different character than is generally thought present. By using geophysical probing, it is possible to infer the location and size of these unusual regions. The ground structure is commonly estimated from core samples taken from boreholes. These cores give a detailed knowledge of the structure in the borehole. However, knowledge of the structure exterior to the borehole can only be extrapolated from core data. By using seismic and electromagnetic cross-borehole geophysical probing, remote probing can be used to sense the region exterior to boreholes. A recent advance has significantly improved the state-of-the-art for defining the ground structure between boreholes. This new procedure utilizes large amounts of data and provides a detailed picture of the subsurface. The data processing algorithms used are similar to those in medical imaging of the human body using x-rays, a science called x-ray tomography. This imaging of the ground is called geotomography, which is a shortened acronym for geophysical tomography. Several examples of geotomography applied to imaging ground structure are presented. Our approach has been to probe the ground with electromagnetic and seismic waves. We map the region of interest with signals transmitted between multiple source and receiver pairs lowered in boreholes on opposite sides of the region (Figure 1). The received signals vary according to the transmission properties of the media

Jan 1, 1979

THE paper on "Cross-cuts in Coal Mining," by J. J. Rutledge (published in MINING AND METAL-LURGY, February, 1927, p. 64) was brought up for discussion at the annual meeting, where the follow-ing comments were made T. D. Thomas (Lehigh Coal & Navigation Co., Lansford, Pa.) : This question has caused me a lot of worry, not in the particular district in which I am, but throughout other districts. There are always several angles to consider. If you are in a hurry to push development work, you might increase the distance between cross-cuts from 60 to 350 ft., but if you have a 40-ft. chain pillar every 60 ft. it will cut down your entry driving a whole lot. Looking at it from the ventilation angle, I agree that too many cross-cuts in entries are bad things. You have a tremendous amount of leakage, and I have seen currents starting out with 45,000 cu. ft., and after passing about 30 or 40 cross-cuts the current has dwindled down to about 18,000 or 15;000 cu. ft. The result is that the question of putting in auxiliary fans is raised. That involves several points into which I do not want to go too far, but I am in favor of not getting in too many cross-cuts, putting them in only where they are necessary: I think the state mining laws are wrong in a number of places on that, and that when you finish with a cross-cut it should be in the room. It should be well sealed on an entry. There are several ways of tightening up the cross-cuts so as not to have the great amount of leakage and wastage of: air that we now have. 'I prefer tile stopping; other people prefer cement or brick, but there is a big fac-tor to all mines, saving the mine. I checked up on the number of fans in the anthracite region and found there are 651. That was derived from the state report of 1921, and it enabled me to compute from the power the weight of the air. In the anthracite region of Pennsylvania we put in 9 tons of air to every ton of coal we get out. Tracing that back again and taking the Government's figures which they made some time ago, I found but 20 per cent of the air got to the faces where it was actually needed. That is a tremendous big loss and shows a possibility for saving, money for the various coal companies. Chairman Rice: I think what Mr. Thomas refers to was an investigation by R. Y. Williams, of the Bureau of Mines in Illinois, where a study was made of 100 typical mines, and, speaking off-hand, my recollection is that we found as little as 15 per cent of air reached the faces in one of the mines and another was as much as 50. That seems to be a reflection on the type of stoppings and general ventilation scheme.

Jan 3, 1927

By J. J. Rutledge

THE first method of working coal mines in the middle western states, more particularly in Illinois, Indiana and Missouri, was by means of the so-called single-entry method. In this method a single main passageway, or entry, was driven in the coal seam. with no parallel passageways, and from this pas-sageway or entry there were turned at intervals sim-ilar cross-passageways or entries, and from these cross-passageways, if the coal seam worked lay fairly horizontal, rooms were turned right and left. These crude methods of working were followed when the com-panies opening the mines were small and of very limited capital, and when the demand for coal was small and irregular. The principal desire was to produce coal in the short-est possible time and at the cheapest price. The chief evil resulting from such method of working was de-fective ventilation, although there were other serious drawbacks. There were then few or no good mining laws and no restrictions on those operating the coal mines. The hours of labor were long, the wages low, and the miners accordingly worked hard. All the coal was either sheared or undercut with a pick by hand. Very little solid shooting and no machine mining was done. What little air entered the mine, openings was introduced through the entries or. headings and thence conducted through the rooms by means of curtains; in many cases, as the workings became more exten-sive, the number of curtains added so materially to the mine resistance that ventilation was extremely in-efficient. Shots were fired by the miners at any time during the working shift and consequently there was more or less powder smoke or fumes in the mine work-ings all day long. Moreover, the working days were much longer than at present. The fine, dry coal-dust falling from the miners' picks while they were shear-ing or undercutting the coal filled the mine atmosphere and was taken into the lungs of the mine employees.

Jan 2, 1927

By William Adamson

Precise and data driven methods of predicting and modelling blast induced vibration intensity are created and applied under field conditions on a routine basis today. These models are fed with controlled field measurements of vibration pulses generated by controlled charges under known geometric conditions. With such models blasting and geomechanical engineers can estimate vibration intensity at established critical points in mine bench geometry (surface mining) as well as within semi-permanent crown and rib pillars (in underground mining).Damage to bench walls and destabilization of large-scale geomechanical structures can be partially attributed to high intensity blast induced stresses on the rock mass and structures that define important features such as safety catch berms and haul roads. In the underground environment, weakening of critical pillars in block caving or Long Hole Open Stoping(LHOS) operations may lead to ore sterilisation. Blast vibration intensity can be linked with physical alteration in critical rock mass volumes within themine. Often the potential for vibration damage is estimated by the calculation of a critical value of vibration intensity, derived from a consideration of laboratory measured rock matrix properties. Efforts to confirm the accuracy of these estimates of critical vibration level include post blast excavation photography as well as the visual examination of rock mass, pre-and post-blast, using video camera observation of the walls of purpose drilled observation holes. These methods clearly indicate a change in fracture state due to the blast induced vibration, however further modelling of geomechanical stability will benefit if seismic measurement data can be interpreted in terms of geomechanically relevant strength parameters. This paper describes some of the results of previously unpublished research studies conducted in underground operations in Chile and Australia, where cross-hole seismic measurement profiles were interpreted in terms of dynamic modulus. This work dates from a period between 1987 and 1990 and the Author suggests that 30 years on, applying modern day technology, instrumentation and modelling methods, more meaningful, practical and applicable results may be obtained.

By William R. Adamson

This paper describes some of the results of previously unpublished research studies conducted in underground operations in Chile and Australia, where cross-hole seismic measurement profiles were interpreted in terms of dynamic modulus. This work dates from a period between 1987 and 1990 and the Author suggests that 30 years on, applying modern day technology, instrumentation and modelling methods, more meaningful, practical and applicable results may be obtained.

Feb 1, 2020

By Andrew Slifka, Pello Uranga, Douglas Glenn Stalheim

Structural steel final mechanical properties of strength and ductility are predominately generated by the final ferrite grain size/packet size and homogeneity of that ferrite grain size/packet size through the cross-sectional area. Forty to seventy percent of the strength components come from how fine the final cross-sectional ferrite grain size/packet size that can be produced.[1] All the ductility properties of structural steels for a given microstructure are predominately driven by how fine AND homogenous the final cross-sectional ferrite grain size/packet size can be refined.[2,3,4] One key ductility property of structural steels used in construction and energy transmission applications is fatigue. Both low and high cycle fatigue can be realized in these end applications, however, low cycle fatigue is typically the predominate mechanism. In construction applications the environment for fatigue is typically air, such as in wind towers or high-rise building construction. In energy applications, there is an interest in high pressure (5.5 – 21 MPa, 800-3000 psi) gaseous hydrogen as an alternative fuel source to fossil fuels. A project to study the effect of the cross-sectional grain size/homogeneity of a relatively pure polygonal ferrite microstructure on the fatigue performance in air and high-pressure gaseous hydrogen has been developed. This paper will discuss the project strategy, microstructure developed for the project and initial test results.

Oct 1, 2019

By Tex M. Kubacki

On August 6, 2007, the Crandall Canyon Mine experienced a collapse which trapped six mine-workers. An MW 4.1 seismic event was recorded in conjunction with this collapse. An additional 54 seismic events were detected and located in the vicinity via routine processing techniques during the month of the collapse. Waveformbased cross-correlation detection techniques have been used to uncover 1,328 small, previously undetected seismic events which occurred near the collapse area between July 26 and August 9, 2007. This work has resulted in lowering the magnitude threshold of completeness from ML 1.6 to ML -0.5, a 2.1 order-of-magnitude improvement over standard processing techniques. Event locations have been computed using a double-difference inversion. The spatial pattern of events ultimately helps to delineate the extent of the collapsed area. It is shown that many of the large catalogued events (>ML1.6) tend to be closely followed by numerous (often 20 or more) smaller aftershocks. Cluster analysis of the known catalog reinforces prior work indicating the existence of seismic clustering on the east and west sides of the collapse. Research now demonstrates that it is possible to differentiate events related to the main collapse from those related to the rescue attempt following the collapse. The cross-correlation techniques described herein greatly improve the ability to detect small mining-induced seismic events. These methods may lead to improvements in assessing seismic hazards for conditions similar to those observed at Crandall Canyon preceding the collapse.

Jan 1, 2013

By C. P. Fang

"For lower stages of multinozzle micro-orifice impactors, as many as two thousand nozzles are uniformly arranged within a cluster diameter of 1.06 inches. In the impaction region the mass flowrate of the spent air increases along the radius and reaches a maximum at the periphery. This crossflow can significantly deflect the air jets of the outer nozzles, hence the characteristics of impaction changes.Investigators in heat transfer and fluid mechanics have studied the influence of crossflow on jet deflection and found the dimensionless deflection of the jet centerline X/Dn is a function of (S/Dn)(l/m) . only, here X is downstream coordinate measured from the center of the jet orifice, Sis the jet-to-plate distance, Dn is the orifice diameter and m is the jet/crossflow mass flux ratio defined as:"

Jan 1, 1989

By Cory McElprang, Enamul Hoque, Aaron Thomas, Scott A. Jacobs

Crosshole Sonic Logging (CSL) only evaluates concrete on the inside of reinforcing cages leaving the outside unevaluated unless other types of testing are performed such as Perimeter Sonic Logging (PSL). While there have been some reports of PSL testing having accurately identified anomalies (e.g. Samtani et al 2005), experience by Case Foundation Company has indicated otherwise where false positives were determined with subsequent coring. Numerous cases of PSL false positives are presented as well as a study where a shaft was installed with both inside and outside tubes, and CSL and PSL data were compared. To date, there is very limited data published on perimeter sonic logging, or Gamma-Gamma Logging (GGL) with tubes on the exterior of drilled shafts. Several cases will be presented where false positives were experienced where PSL testing was performed. In addition, a direct comparison will also be presented where a shaft was installed with both tubes on the inside and outside where CSL and PSL data is compared. BRIEF HISTORY – CSL TESTING AND TUBES ON INSIDE The general procedure of Crosshole Sonic Logging (CSL) testing includes attaching tubes to the reinforcing cage to be able to send a transmitter in one tube and a receiver in another tube with which a sonic pulse is emitted from the transmitter and received in another tube. The time taken for the sonic pulse to travel between the tubes is measured and compared to expected values for the known distance between the tubes. Any increase in time from expected values indicates the sonic pulse traveled through a media other than homogeneous concrete such as objects in the path (spacer wheels, steel bracing, etc.), tube spacing, or soil inclusions. However, variations in arrival time can also result from differences in concrete density. The tubes have traditionally been placed on the interior of the reinforcing cage which protects them during hoisting and placement of the cage and reduces wave refraction caused by modulus of elasticity differences between steel and concrete. This allows the concrete within the interior of the reinforcing cage to be evaluated, but the concrete outside of the cage is excluded from traditional CSL testing. As a result, alternative integrity testing has been developed to not only provide different ways to evaluate the integrity of drilled shafts but to also address the issue of evaluating the concrete outside of the reinforcing cage. These alternative testing methods include Gamma-Gamma Logging (GGL), Thermal Integrity Profiling (TIP testing) and Perimeter Sonic Logging (PSL) which is similar to CSL testing but instead of the tubes placed inside the reinforcing cage, the tubes are placed on the outside of the reinforcing cage as shown in Fig. 1.

Jan 1, 2019

By Taner Aydogmus

The A$29 billion Chevron-operated Wheatstone Project is one of Australia’s largest resource projects. Located at Ashburton North, 12 kilometers west of Onslow in Western Australia, the project will consist of two Liquefied Natural Gas (LNG) trains with a combined capacity of 8.9 million tons per annum and a domestic gas plant. The LNG Plant will serve the offshore gas fields, which are situated some 250 km off the coast of Onslow in Western Australia. Once operational and on-stream, the Wheatstone Project will contribute to Australia becoming the world’s second largest exporter of LNG. For crossing the environmentally sensitive shore area, a micro-tunnel with an internal diameter of 2 m and approx. 1,242 m in length has been constructed by means of the pipe-jacking method. The micro-tunnel will accommodate a 1.1 m diameter pipeline (trunkline) to deliver gas from the offshore fields LNG Plant. The Wheatstone shore crossing design involves a number of unique challenges owing to its coastal location, where the alignment crosses through a shore area and terminates in a marine environment. This paper provides an overview of the Wheatstone Shore Crossing Project, presents the key features, and discusses the main aspects of the micro-tunneling design.

Jun 13, 2021

By Tamás Megyeri, Dániel Borbély, Vera Szánto, László Kovács

"Upon completion, the Bátaapáti deep underground radioactive waste repository complex (National Radioactive Waste Repository - NRWR) will provide safe final disposal for low and medium-level radioactive waste from the Paks Nuclear Power Plant in Hungary. The waste emplacement is in progress and one of the main concerns related to the development is ensuring a feasible plan is in place for permanent repository closure. Detailed hydrogeological observations and safety assessments revealed that the clay filled fault zones penetrated with the access tunnels play determinant role in the long-term confinement performance of NRWR, so they need to be plugged. Detailed mechanical analysis and numerical modelling of the tunnel constructed through a fault zone is presented here to gain a better understanding of the rock mass and rock support behavior. The effect of stress reflection is demonstrated and its consequences are described in detail. A recommendation is given for tunnel support design in such conditions. INTRODUCTION Crossing fault zones is a challenging task during tunnel construction and can lead to failure if not properly accounted for during design and construction. These failures are can be caused by high water inflow or stability loss of the rock mass surrounding of the tunnel (examples can be found in CEDD, 2015). The prediction of the magnitude and development of displacement has a considerable impact on issues during tunnel construction. Changes of rock mass stiffness or structure ahead of the face, to a great extent influencing stresses in the vicinity of the tunnel and thus deformations (Steindorfer, 1998). Further research with numerical simulations was carried out, and the qualitative and quantitative evaluation of displacement vector is presented in (Grossauer et al, 2005). The concern associated with crossing fault zones was considered during the design of the Bátaapáti deep underground radioactive waste repository complex (NRWR) in Hungary. In the case of NRWR project, the fault zones have an impact on maintaining the stability of the surrounding rock mass as well as the final sealing of the repository. As part of the final closure design, a complex numerical modelling program was completed to gain a better understanding of the mechanical behavior of the rock mass and the monitoring observations during construction. Even though the need for the presented study is closely related to the NRWR project, the results can be used in any project related to fault zone crossing. The methodology used to better understand the impact of crossing fault zones for the NRWR project is presented in this paper. First the project background is introduced including an overview of the underground facilities, the aim of the repository, and the construction experience gained from the first crossings of the fault zones. After that the in-situ and laboratory testing is summarized. The numerical modelling methodology is detailed in the next section. Not only the outcome of the model is presented, but the results are compared with the experience and observations made on site. Since a good agreement is found between the actual and the modelled behavior, the conclusions are based on the validated result. To fulfill the aim of the paper, the stress reflection concept is introduced to explain the mechanical behavior of the fault zone and the rock support; furthermore straightforward suggestions are made for rock support design."

Jan 1, 2016

By Tom Dettweiler

Who We Are A global pioneer in discovery, development and recovery of deep-ocean assets Shipwrecks Deep-sea Minerals Company Overview Founded 1994 HQ ?Tampa, Florida USA Employees 45 Tampa + 150 Abroad Publicly Traded: NASDAQ:OMEX Requires Specific Financial Controls and Reporting

May 1, 2013

By Jess H. Albino, Girish Roy, James M. Monsees

Construction of the North Hollywood line of the Los Angeles Metro System required crossing the Hollywood Fault as the twin transit tunnels extend into the San Fernando Valley. The Hollywood Fault is considered active and represents the largest active fault that the North Hollywood Redline extension will cross. The feature is a thrust fault with the north plate overriding the southern plate and creating the Santa Monica Mountains in the process. South of the fault lies the alluvial valley and Hollywood. North of the fault are the Santa Monica Mountains which rise locally to more than 1200 feet. The average overburden at the seismic section is about 300feet and is overlain by Runyon Canyon Park, a municipal park with environmentally sensitive areas. The actual fault plane was anticipated to lie within the southernmost120 feet of the 600 to 700-foot-wide fault zone. The special seismic section constructed for the tunnels consisted of an enlarged cross-section with special lining, drainage and finish features that will facilitate the restoration of metro service in case of a major event occurring on the Hollywood Fault. The discussion will address the geology, the procedure used to define the design event and predicted displacements, the unique design features as well as the construction methods used and the instrumentation and the results obtained.

Jan 1, 1999