When starting a new mine, whether it's a open pit or an underground mine, the designer faces many challenges! One of these is the understanding of rock mass conditions and how this affects the choice of mining methods and the mine design at an early stage.
In the context of a wine cellar extension project, a 20cm thick concrete slab is to be constructed on a soil reinforced by rigid inclusions. Itasca France has been called by the design office to verify the mechanical resistance of the concrete slab and assess its settlement under a uniform load.
The city of Kiruna is partly located on the hanging wall side of the LKAB Kiirunavaara Mine. In the long-term perspective, it is not possible to have any residential buildings or infrastructure within the fracture zone and cave zone resulting from mining. An urban transformation process for the Kiruna city center is thus currently underway. The current prognosis is empirical based on observations since the early 1960s until today.
In the framework of the development of a subsea tidal turbine, the design of the foundations has to be optimal. Cathie Associates, on behalf of HydroQuest, wanted us to investigate the penetration of a single steel foundation pin in a granitic rock mass by using a discrete numerical approach and follow the state of the damaged zone around the tip during penetration.
The Kevitsa open pit mine has been in operation since 2012 and was acquired by Boliden in 2016. A new strategic plan is currently being developed to investigate an increase in production. In conjunction with this, the geotechnical slope design parameters for the final pit depth, including a possibly deeper pit, need to be analyzed.
Open pit mining often result in high rock slopes, sometimes combined with difficult rock conditions. This is further augmented by large blasting rounds resulting in high vibrations. Reinforcement of pit slope walls is also difficult and many times associated with high costs and loss of production. Bench slope stability is vital for a safe working place for all personnel in the mine as well as for avoiding production loss. Itasca Consultants AB is providing technical, on-site rock mechanics expertise to several open pit mines in northern Sweden.
Boliden Tara Mines is Europe’s largest zinc mine, with an annual production of 2.6 million tones of ore, and has been in operation since 1977. This project was part of the required planning application to the authorities regarding crown pillar extraction in the norther portion of Boliden Tara Mines. It was conducted in two phases – first a continuum model was analyzed in FLAC3D, which was then followed by a discontinuum modelling in 3DEC with included faults.
Located near Fisherman’s Wharf in San Francisco, North Shore Pump Station is a part of the North Point Wet-Weather Facility (NPF), which provides primary treatment for disinfection of wastewater. The facility is a two-story building that is completely embedded in soil, and the subsurface conditions include potentially liquefiable sand layers and soft Bay Mud deposits sitting on bedrock sloping toward the east side waterfront. The building is supported by piers extending all the way into the Franciscan Complex bedrock.
A baked anode is a complex material, that results from the mixing and baking of different petrol coke grains, with different size distributions, with a pitch. A preliminary study (ICSAS16-CST-MFG-35143-01) developed a PFC2D model accounting for the microstructure of a baked anode, using the Bonded Particle Model (BPM).
The mine is interested in using the decommissioned open pit for storage of tailings from the underground mine, as this would be beneficial both from an environmental and an economical perspective. The implementation will be a technical challenge since portions of the crown pillar separating the open pit from the underground mining has been extracted.
A parking ramp expansion has been proposed at Terminal 1-Lindbergh to be constructed over the north end of the Metro Transit Light Rail (LRT) station. Itasca assessed the magnitude of the principal impacts by conducting three-dimensional geostructural analyses of the LRT station using 3DEC. Of the six designs evaluated, all but one option were predicted to be geostructurally feasible.
The aims of this work is to study the influence of face reinforcement on the tunnel stability and to check if the creep behavior of the rock may induce a potential jamming of the TBM during the excavation stop.
Project on the extension works for the Underground Research Laboratory (URL) at Bure (France).
The Björkdal mine ("Björkdalsgruvan"), located 28 km northwest of the town of Skellefteå, is a gold mine with the mineralization typified by Au-quartz veins located within a metamorphic package. The Björkdal mine is operating with both open pit- and underground mining. During spring 2016 the mine experienced local slope instability at one of the open pit walls. The concern was how it would affect safety for the mine workers and future mining, but also if it was safe to remove loose rock mass without endangering workers or interrupt any mining activities.
A baked anode is made of a complex material, obtained by mixing and baking different petrol coke grains, with different size distributions, with a pitch. Hydro PMT needs to study how cracks propagate in such a material – both within and between grains. Representing properly the non-spherical grain shapes, as well as the porosity, both between grains and within the coke grains, are therefore prerequisites.