Rapidly changing economic conditions can be stressfully challenging in any environment, particularly in the industries that Itasca serves. For more than 25 years, Itasca has offered consulting and software services that can alleviate business pressure, whether it be to improve efficiency, maximize opportunities or resources, supplement the work of existing business units, or to provide a cost effective alternative for executing specific projects. We invite you to consider whether your present circumstances could profitably benefit from Itasca's expertise in geomechanics, hydrogeology and hydrology, and numerical modeling.

– Loren Lorig, Chief Executive Officer

HCItasca Denver, Inc.–
DEPRESSURISING AN UNDERGROUND ORE BODY AT THE MCARTHUR RIVER MINE IN NORTHERN SASKATCHEWAN, CANADA

Pre-mining depressurising of a deep ore body at the McArthur River mine in northern Saskatchewan ((1) below) was under consideration — both to decrease the risk associated with mining near 5 MPa water pressure and to increase the amount of ore that can be extracted. Currently, ground freezing is used to isolate the ore from this high pressure groundwater. However, this methodology only enables ore to be extracted from the lower portion of the Zone 4 orebody without additional freezing and utilizing the boxhole boring method. Due to the high water pressure and low rock strength, potential ground failure currently presents a challenge to extraction of a significant portion of the ore in the upper part of the Zone 4 orebody ((2) below).

Based on a limited amount of field data, a three-dimensional finite element groundwater flow model using MINEDW was developed. The model was used to determine the amount of water that would have to be pumped from surface wells or extracted with underground drainholes to reduce the pore pressure of the upper part of Zone 4 orebody from 5 MPa to about 1-2 MPa. In addition, the model predicted the associated magnitude and extent of drawdown that would propagate to the surface over the life of the operation and its impact on surface-water resources. Results from the preliminary model were used to design a prototype depressurising well and a 30-day pumping test. Because of the predicted large volume of water (about 2,000 m3/hr) that would have to be discharged, another investigation is being conducted to assess the effectiveness of localized depressurisation in improving mine tunnel stability in conjunction with ground freezing and cementaceous grouting.

UDEC 4.01 Upgrade Available Now

UDEC 4.01 is a free upgrade available to all current UDEC 4.0 users. It contains a number of new features, including a number of enhancements to the user interface. A complete list of additions to the upgrade is available on the download page. The upgrade may be installed and run alongside existing UDEC 4.0 installations.

New code demonstration version  

A new demonstration version of UDEC 4.01 is available for download now. As with the existing demo versions of FLAC, 3DEC, PFC2D, and PFC3D, this version of UDEC is fully functional. The demo version is free, has no time limit, and includes the complete code documentation. Demo UDEC can cycle a model requiring up to 280Kb of memory; larger models may be constructed and viewed in this version, but they may not be cycled. The demo version is subject to Itasca's license terms and conditions. More information on UDEC 4.01 is available above.

New PFC 4.0 Example

An example application using PFC for molecular dynamics (MD) simulation, which involves solving the classical many-body problem in contexts relevant to the study of matter at the atomistic level, is available online now. In five sections the example problem details aspects of this problem and the implementation in PFC for approaching it.

"Appraising the Brooklyn Bridge" is the title of the article featured on the cover of the the February issue of Civil Engineering magazine. In the article, the authors describe the effort to perform a comprehensive seismic evaluation of the Brooklyn Bridge to assess its vulnerabilities and potential retrofit requirements. The work was performed for the New York City Department of Transportation (DOT) by the New York City office of Parsons Corporation and Northeastern University. FLAC was used extensively in this effort to evaluate the effect of ground motion on the bridge towers and their caissons. Partially as a result of this work, Itasca has been selected to perform a similar analysis on the Madison Avenue Bridge in New York City.

The annual Spring FLAC, FLAC3D, 3DEC, and PFC introductory software training courses at Itasca Consulting Group Inc. in Minneapolis will commence in less than a month. Registration is available on a first-come, first-served basis. There is still space available in each class, but the registration deadlines for these courses will begin this week (registration deadlines are one month prior to the start of each course). See the "Schedule of Courses" on the Training page for more info.

Windows Vista and "Program Files"

Under common Windows Vista security settings, programs are not allowed to write files to the "Program Files" area of the hard drive; output intended to be written there is redirected to the current user's profile. This can create problems — or confusion — when running Itasca software. A simple way to avoid this problem is to create a shortcut to the program and copy the shortcut to a user-created location. By deleting the contents of the "Start In" attribute (see the shortcut's properties) the program will use the location of the shortcut as the working directory for that program (and all output will be directed there by default).

Connell, L. D., and C. Detournay. (2008) "Coupled Flow and Geomechanical Simulation of Gas Production from Coal Seams," in CD Proceedings, 2008 Asia Pacific Coalbed Methane Symposium (September 2008). Paper IL006, P. et al., Eds. Brisbane, Australia: University of Queensland, Chem. Eng. & Earth Sci.

Connell, L. D., and C. Detournay. (2008) "Coupled Flow and Geomechanical Processes During Enhanced Coal Seam Methane Recovery Through CO_2 Sequestration," Int. J. Coal Geol., 77, 22-233.

Deisman, N., R. J. Chalaturnyk and D. Mas Ivars. (2009) "An Adaptive Continuum/Discontinuum Coupled Reservoir Geomechanics Simulation Approach for Fractured Reservoirs," in 2009 SPE Reservoir Simulation Symposium (The Woodlands, Texas, February 2009). Paper No. SPE 119254.

Deisman, N., D. Mas Ivars and M. Pierce. (2008) "PFC2D Smooth Joint Contact Model Numerical Experiments," in '08: A Heritage of Innovation (61st Canadian Geotechnical Conference, Edmonton, September 2008). Paper No. 83.

Deisman, N. et al. (2008) "Geomechanical Characterization of Reservoirs: The SRM Approach," in CD Proceedings, 2008 Asia Pacific Coalbed Methane Symposium (Brisbane, Australia, September 2008). Paper 003, P. et al., Eds. Brisbane, Australia: University of Queensland, Chem. Eng. & Earth Sci.

Konietzky, H., Heftenberger, A., and M. Feige. (2009) "Life time prediction for rocks under static compressive and tensile loads - a new simulation approach," Acta Geotechnica, 4: 73-78.

Pierce, M. (2009) "The Mechanics of Caving in Jointed Rock," presented at the Institute Colloquium (January 20, 2009). University of Toronto, Institute.

Pierce, M., D. Mas Ivars and B. Sainsbury. (2009) "Use of Synthetic Rock Masses (SRM) to Investigate Jointed Rock Mass Strength and Deformation Behavior," in CD Proceedings, International Conference on Rock Joints and Jointed Rock Masses (Tucson, January 2009). Paper 1091, P. H. S. W. , Ed. Tucson: & Associates.