At the Society for Mining Metallurgy and Exploration (SME) meeting in St. Louis in May the general feeling was that the outlook for mining is the best it has been for 30 years. Keynote speakers suggested that the current boom cycle would extend beyond the normal seven to ten year cycle. Our consulting business is growing not only for the mining industry but for the petroleum, civil engineering, and material handling sectors as well. We are gratified by the challenging assignments we have received and are always looking for more. If you are motivated by developing innovative solutions to challenging problems, we would like to hear from you.

—John Markham, Executive Officer

 

17th Street Canal breach after Hurricane Katrina


FLAC model illustrating the failure of the leveeFrom March through May, 2006 Christine Detournay and Yanhui Han of Itasca Consulting Group, Inc. developed a FLAC template to assist the U.S. Army Corps of Engineers in evaluating and reconstructing flood protection in New Orleans. The design objective of the template was to compare alternatives for stabilizing or minimizing movement of existing flood protection measures in various locations. The main features of the template include parameterized geometry and soil strata, varying soil parameters (Mohr-Coulomb) such as cohesion, bulk and shear modulus vertically and laterally, wall (beams) interacting with soils through interfaces, varying water levels, and gap formation increments. The template was used to investigate the scenario of a gap forming along the canal side of the wall, and to study the impact of the full Katrina water level pressure acting within this gap. This mechanism is able to explain the large failure and translational displacement observed at the 17th Street Canal breach location, and is an integral part of the new design process. According to USACE, the template results from the 17th Street Canal analysis agree well with observed conditions and with results from work by others using advanced constitutive models. The template is being used to support design alternative decisions for different locations and may be shared with other offices within USACE as a generic analysis tool.

 

Update Alert:
Current Versions
updated since
Feb. 28, 2006:







New Code Release
The pre-release version of FLAC3D 3.1 is now available. The final version of FLAC3D 3.1 will contain the following features:

• Parallel processing for multi-processor computers
• Nodal Mixed Discretization (NMD)
• Embedded Liner
• 64-bit Version
• New HTML Help Documentation

The pre-release does not contain full implementation of these features; they will be added into the pre-release as development on the code continues. For complete information on the state of pre-release development and further information, please visit the FLAC3D 3.1 Pre-release page on our web site.

 

Office 3126, Tokai University
3-20-1, Orido, Shimizu Shizuoka, SHIZUOKA 424-8610 JAPAN
phone/fax: +81-543-35-5600
email: itasca@itasca.co.jp Continued Growth:

New Office
HCItasca is pleased to announce the organization of a new branch office in Japan, Itasca Consulting Group, Inc. Japan. The office is headed by Dr. Yoshiyuki Shimizu, and will, like all Itasca offices, provide consulting services and software sales and support.

New Joint Venture
Groundwork Consulting (Pty) and Itasca Africa (Pty) Ltd. are pleased to announce the formation of a new company, the Itasca-Groundwork JV, which will enable clients to obtain comprehensive rock engineering solutions from one entity. The two existing companies will also remain fully operational and will continue to provide their current specialized services to clients. The new JV will provide practical and sustainable rock engineering solutions by integrating geotechnical characterization, numerical modeling, and monitoring of the rock mass and ground support. In order to facilitate the provision of the comprehensive rock engineering solutions, Groundwork Consulting and Itasca Africa are now working from the same premises in the Auckland Park district of Johannesburg. For further information regarding the Itasca-Groundwork JV please call Phil Piper, Francois Malan, or Tony Leach at 011 483 8838 or visit their web sites: www.groundwork.co.za and www.hcitasca.com.

New Staff
HCItasca staff additions of the last eight months include: Rex Bell at HCI, Marty Hudyma at Itasca Consulting Canada Inc., Catalina Alvarez at Itasca S.A., and Andrew Corkum, David DeGagne, Jason Furtney, and Brian Houska at Itasca Consulting Group, Inc. (ICG). In addition, Nathan Deisman of the University of Alberta is doing a summer internship with ICG from May through August. A warm welcome to all our new arrivals.

 

Get the Proceedings 4th FLAC Symposium Report
The Fourth International FLAC Symposium, held May 29-31 in Madrid, was a success. Attendees had the chance to hear over 50 papers on the use of FLAC and FLAC3D in the areas of: slopes and embankments; underground structures; coupled processes and fluid flow; dynamic analysis; soil-structure interaction; tectonics; numerical techniques; and constitutive models/material behavior. We would like to thank all who attended for a truly memorable experience.

If you did not have the chance to attend the symposium, you can still find out what you missed by getting the Symposium Proceedings and/or the Symposium Presentations. The Proceedings CD is available for purchase from Itasca Consulting Group. The Presentations CD is available free on request (shipping charge is applied).

 

Initial Announcement
Itasca Consultants GmbH, in cooperation with the Technical University of Freiberg, will organize an Itasca code seminar on November 16, 2006. The following day the university will host the Geomechanical Colloquium. Complete information on the seminar will be provided in upcoming issues of Groundworks.

 

A UDEC model for simulation and geomechanical investigations for Longwall Top Coal Caving technology

Interesting model features include: fully dynamic movement of the support; simulation of hydraulic pressure of support by using support element feature in UDEC; release and closure of the canopy flipper to draw the caved coal from the rear AFC; rear AFC extraction of the caved coal; and, calculation of total recovery of top coal.

The project is part of research work on Longwall Top Coal Caving technology at the School of Mining Engineering, University of New South Wales, Australia. The work is performed by Abouzar Vakili (UNSW), Yue Jun Cai (UNSW) with external assistance from Brett Poulsen (CSIRO) and under the supervision of Professor Bruce Hebblewhite (UNSW).

 

Publications since February 28, 2006:

Bock, H., Blümling,P. and Konietzky, H.: "Study of the micro-mechanical bahaviour of the Opalinus clay: an example of co-operation across the ground engineering disciplines" Bull. Eng. Geol. Env. (2006) 65: 195-207.

Bourdeau C. and Billaux D. "Analysis of geogrids'efficiency to prevent a local collapse of a road", in Proccedings of the 2006 Geosynthetics Meeting, Montpellier, June 2006.

Burlingame, M. J., A. M. Fouda and R. D. Hart. "Modeling of Landfill Stability with Vertical Barrier Walls: A Practical Example Using Limit Equilibrium and Numerical Methods," in Geotechnical Engineering in the Information Technology Age (Proceedings of Geocongress 2006, Atlanta, February-March 2006), CD Proceedings, ISBN 0-7844-0803-3. D. J. DeGroot et al., Eds. Reston, Virginia: ASCE, 2006.

Chan, T., R. Christiansson, G. S. Boulton, L. O. Ericsson, J. Hartikainen, M. R. Jensen, D. Mas Ivars, F. W. Stanchell, P. Vistrand and T. Wallroth. "DECOVALEX III BMT3/BENCHPAR WP4: The Thermo-Hydro-Mechanical Responses to a Glacial Cycle and Their Potential Implications for Deep Geological Disposal of Nuclear Fuel Waste in a Fractured Crystalline Rock Mass," Int. J. Rock Mech. Min. Sci., 42, 805-827 (2005).

Hannweg, L., L. Lorig, G. van Hout and A. Guest. "Koffiefontein Mine Front Cave — Case History," in Proud to Be Miners (Proceedings of MassMin 2004, Santiago, August 2004), pp. 393-396. A. Karzulovic and M. A. Alfaro, Eds. Santiago: Mineria Chilena, 2004.

Langmuir, D., Mahoney, J.J., and Rowson, J.W., 2006, "Solubility products of amorphous ferric arsenate and crystalline scorodite (FeAsO4.2H2O) and their application to arsenic behavior in buried mine tailings". Geochimica et Cosmochimica Acta, vol. 70. p. 2942 -2956.

Mahoney, J., Langmuir, D., Gosselin, N., and Rowson, J., 2005, "Arsenic readily released to pore waters from buried mill tailings." Applied Geochemistry, Vol. 20 (5), p. 947 -959.

Mahoney, J., Langmuir, D., and Rowson, J., 2005, "A method to measure arsenic readily released to pore waters from uranium mill tailings," in Merkel, B.J. and Hasche-Berger, A., eds., Uranium in the Environment - Mining Impact and Consequences, Springer, Berlin, p. 97 - 106. (Presented at Uranium Mining and Hydrogeology Congress IV, Freiberg, Germany - September 2005.)

Mahoney, J., Langmuir, D., Slaughter, M., and Rowson, J., 2005, "Raffinate neutralization experiments at the McClean Lake Mill - removal of arsenic and nickel", in Merkel, B.J. and Hasche-Berger, A., eds., Uranium in the Environment - Mining Impact and Consequences, Springer, Berlin, p. 225 - 234. (Presented at Uranium Mining and Hydrogeology Congress IV, Freiberg, Germany - September 2005.)

Mas Ivars, D. "Water Inflow Into Excavations in Fractured Rock - A Three-Dimensional Hydro-Mechanical Numerical Study," Int. J. Rock Mech. Min. Sci., 43, 705-725 (2006).

McDowell, G.R., Harireche, O., Konietzky, H., Brown, S.F. and Thom, N.H. "Discrete element modelling of geogrid-reinforced aggregates" Geotechnical Engineering (2006) 159: 35-48.

Ruest, M., P. Cundall, A. Guest and G. Chitombo. "Developments Using the Particle Flow Code to Simulate Rock Fragmentation by Condensed Phase Explosives," in FRAGBLAST - 8 (8th International Symposia on Rock Fragmentation by Blasting, Santiago, Chile, May 2006), pp. 140-151. Santiago: Editec, 2006.

Tucker, M., S. S. Kanchibotla and M. Ruest. "Modelling Coal Loss in Open-Pit Blasting Using PFC2D," in FRAGBLAST - 8 (8th International Symposia on Rock Fragmentation by Blasting, Santiago, Chile, May 2006), pp. 109-113. Santiago: Editec, 2006.

Varona, P., and R. Hart, Eds. FLAC and Numerical Modeling in Geomechanics - 2006 (Proceedings of the 4th International FLAC Symposium, May 2006, Madrid). Minneapolis, Minnesota: Itasca Consulting Group, Inc., 2006.
[The Symposium Proceedings includes a number of articles by HCItasca staff, including: C. Bourdeau, P. A. Cundall, C. Detournay, E. Dzik, P. Gomez, Y. Han, R. Hart, M. Pierce, D. Sainsbury, R. Taghavi, and H. Zhu]

Watson, A. D., C. D. Martin, D. P. Moore and L. J. Lorig. "Integration of Geology, Monitoring and Modelling to Assess Rockslide Risk," Felsbau, 24(3), 50-58 (2006).