Fragmentation is an important aspect of all block caving operations. The primary fragmentation can be difficult to assess, in particular in complex geological environments, and for rock masses subjected to varying stress as is normally the case in block caving.
Boliden is investigating the Laver low-grade copper deposit for potential future mining. The old Laver deposit was discovered in the 1930s, and was operated between 1938 and 1946. Mining was primarily conducted as small-scale underground mining, but a small open pit was also in operation at that time. The currently investigated deposit is of larger scale and with lower grades. Investigations have been on-going since 2008, including geophysical investigations, outcrop mapping, sampling of drill cuttings, and diamond core drilling. The mineralization is not defined at depth and/or in strike extension.
Using blasting caps with electronic delay units, and programmable delay times down to 1 ms, it has become possible to employ wave superposition in rock blasting. It has been hypothesized that fragmentation is improved in areas between blastholes where the tensile waves meet, overlap and interact. An improved fragmentation can, in turn, result in reduced costs for both blasting and transportation of the blasted rock, improved environmental aspects, and reductions in energy consumption during crushing and grinding of the blasted rock, as well as improved metal recovery. In this project, the above hypothesis was further studied in conjunction with developing computational tools for simulation of blasting with electronic programmable delay caps.
In 2003, a landslide developed along the Red Lake river bank inside the city of Crookston, Minnesota. Although several attempts were made to solve the problem, in 2008, a second event occurred, and extensive instrumentation was then put in place to monitor the slope and gain a better understanding of the situation. In 2013, the Minnesota Department of Transportation issued a design and build project to improve the stability of the river bank.
This project involved simulating the proposed open pits and underground mining of the Aurora Mine in Guyana, predicting potential inflow rates into the pits and underground workings, and providing pore‐pressure distributions to the geomechanical model.
Determine the mechanical behavior of a stone arch bridge during the phase of the formwork removal.
Many gold mines in South Africa are situated 2 to 4 km deep in sedimentary deposits extending for hundreds of square kilometers along mostly tabular reefs often less than one-meter thick. AngloGold Ashanti’s operational depth of mining increases every year following a declining gold reef with the surrounding rock experiencing large displacements. The mine seeks to understand the rock behavior, especially brittle failure mechanisms, inherent at depth with the ultimate goal being to develop a rational methodology for mine design, especially as mining continues deeper.
A numerical analysis was conducted to assess the long term stability of the rock caverns BMA and BLA for the final repository of low and middle level nuclear waste at the SFR facility in Forsmark, Sweden. The objective was to analyze if there exists a long term risk for an ongoing loosening of the rock mass up to the surface due to degradation and weathering of the rock mass adjacent to the walls of the rock caverns.
The behavior, during excavation, of a shallow tunnel cutting densely fractured limestones and dolomites raised concerns. The tunnel is called "Drumanar tunnel‘ and located in Louisville, in Southern Indiana. The model geometry is shown on Figure 1.
The Northern Link (Norra Länken) will be part of a major road system surrounding the Stockholm metropolitan area. As part of the design work for this project, Itasca Consultants AB and Itasca Consultants S.A.S. has performed a three-dimensional numerical study to analyze of the effect of a large surface load being applied on top of a tunnel intersection with low (4 m) rock cover. The analyses were performed using FLAC3D, and the model was constructed with KUBRIX Geo mesh generator using in conjunction with the Rhino CAD package.
Mining-induced seismicity is one of the most serious rock mechanics problems in sublevel caving in the LKAB mine in Kiruna.
The design of the final nuclear repository design has been initiated by SKB and as a first step the system design of the underground facility has been executed.
A new loading system to limit segregation of a limestone-coal mix loaded in a cylindrical hopper (2012)
SOLVAY S.A. wanted to characterize the potential segregation of a mix of blocks (limestone + coal) charged into a cylindrical hopper. An intermediate loading structure between the conveyor and the hopper is added to limit segregation observed in a previous study.
In the framework of the extension of the Meuse/Haute‐Marne Underground Research Laboratory (France), Itasca Consultants SAS was commissioned by EIFFAGE to verify the tunnel stability and the design of the support structures installed during the excavation of two intersecting tunnels (Figure 1).In the framework of the extension of the Meuse/Haute‐Marne Underground Research Laboratory (France), Itasca Consultants SAS was commissioned by EIFFAGE to verify the tunnel stability and the design of the support structures installed during the excavation of two intersecting tunnels (Figure 1).