February 2008
I am pleased to have this opportunity to greet you at the start of a new year and say, in my first address in this space, how privileged and excited I am to lead HCItasca into the future. I also would like to thank John Markham, our new CFO, for his many years of outstanding leadership. For more information about changes in HCItasca leadership, see HCItasca World below. Best wishes to friends and clients for a prosperous and productive 2008.
Loren Lorig, Chief Executive Officer
The design of open pits normally involves several scales of analysis (bench, interramp, overall) where different acceptability criteria apply. There is no unique methodology to perform the bench/berm design process; several approaches are proposed. The methodology that Itasca uses is based on statistical analysis of the interaction between the structural sets identified in the wall to be designed and the application of a catchment criterion to decide the appropriate bench geometry.
With encouragement from the mining industry to improve the efficiency of these calculations, Itasca S.A. has developed an automated, faster, more reliable calculation process. As a result, the codes SWISA (for wedge failures) and PFISA (for planar failures) have been created.
The codes perform a statistical analysis of the volumes of unstable wedges formed by the joint sets in a slope wall. The basic input is the statistical information of wall orientation, joint sets (dip and dip direction), bench face angle, bench height, cohesion and friction angle for the joints, and unit weight of the rock.
The main characteristics of the analysis are:
Both SWISA and PFISA are run internally by Itasca as Excel spreadsheets, but, eventually, the two tools will be made commercially available to the geotechnical community. To see and find out more about SWISA and PFISA, please see the complete description at our web site.
Automatic remeshing (or rezoning) logic is now available in the FLAC 6.0 pre-release for large- strain models, including dynamic simulations. This feature allows the model to pause cycling when a "bad geometry" error might cause a halt to the model run, rezone the model, and continue the simulation uninterrupted. A PDF file documenting the logic and a few demo examples and corresponding data files are included in the pre-release update available on our web site.
As bad-zone geometries threaten to halt the model, automatic remeshing performs a re-mapping of zones (preserving accuracy in the calculations) to restore integrity to the mesh and allow further cycling.
Introductory software training courses are coming this Spring. Registration for each class is limited, so don't delay signing up. More information - including course outlines and a registration form - is available on the Training page.
FLAC | April 7-9, 2008 |
FLAC3D* | April 14-16, 2008 |
3DShop | April 21-23, 2008 |
UDEC | April 28-30, 2008 |
3DEC* | May 5-7, 2008 |
PFC | May 12-15, 2008 |
Literature by HCItasca personnel recently published or acquired in the HCItasca library.
Andrieux, P. P., R. K. Brummer and H. Li O'Connor. (2007) "Elastic Versus Inelastic Numerical Modelling of Deep and Highly Stressed Mining Fronts," in Deep Mining 07 (Fourth International Seminar on Deep and High Stress Mining, November 2007, Perth, Australia), pp. 51-57, Y. Potvin, Ed. Perth: Australian Centre for Geomechanics.
Board, M., B. Damjanac and M. Pierce. (2007) "Development of a Methodology for Analysis of Instability in Room and Pillar Mines," in Deep Mining 07 (Fourth International Seminar on Deep and High Stress Mining, November 2007, Perth, Australia), pp. 273-282, Y. Potvin, Ed. Perth: Australian Centre for Geomechanics.
Hudyma, M. R., and D. Heal. (2007) "Proactive Versus Reactive Seismic Monitoring in Mines --- Results of a Seismic Monitoring Survey," in Deep Mining 07 (Fourth International Seminar on Deep and High Stress Mining, November 2007, Perth, Australia), pp. 207-219, Y. Potvin, Ed. Perth: Australian Centre for Geomechanics.
Mercier-Langevin, F., and M. R. Hudyma. (2007) "The Development and Implementation of a Comprehensive Seismic Risk Management Plan at Agnico-Eagle's LaRonde Mine," in Deep Mining 07 (Fourth International Seminar on Deep and High Stress Mining, November, 2007, Perth, Australia), pp. 221-232, Y. Potvin, Ed. Perth: Australian Centre for Geomechanics.