Projects

Mines & Quarries Rock Stabilization Projects

Golden Sunlight Mines, Montana

Janod was called in by Golden Sunlight mines in early September 2006 because of a potential large scale failure. The area that was of most concern for the mine was the Fenner Pinacle and that is what Janod was contracted to remove. The Fenner Pinacle was a structure that had become detached from the rest of the unstable area and formed a pinnacle. Because the Fenner Pinnacle was moving at a faster pace then the rest of the failure area, the mine was concerned that the structure could completely fail at any time.

As in all stabilization projects the first step was to scale out the loose material above the work area and to remove all of the loose rock that would pose a danger, then to observe the reaction of the Fenner Pinnacle to the pounding of the material that was being scaled from above. The next step was to install a system to safely evacuate the Rock Remediation Technicians in case the structure started to move while they were drilling it. We installed a “High Line” from a safe area above the Pinnacle to a safe area below the Pinnacle. We set up two (2) “Geronimo’s” and tested the system to make sure that the men would be able to descend down the slope and away from the Pinnacle quickly and safely; this system worked beautifully. After the Fenner Pinnacle was successfully removed, ring nets were installed as a drape system and tied by two (2) anchor points on either side of the unstable material. The ring nets were then pulled up from the bottom and attached together. The goal of the nets was not to completely stop the material from falling but to reduce the energies of the blocks by restraining them in the net. Each ring in the system has a capacity of 10 tonnes, as a flexible system it could retain a lot more material.

As a testament to the efficiency of the system, about six (6) months after the system was installed there was a heavy rainfall event. Because of the unusually heavy rainfall a lot of material was dislodged from the slope and ended up falling down the chutes where the ring nets were installed. According to the shift foreman that night, the system was lit up like the 4th of July with the sparks caused by falling rock hitting the ring nets. The following morning the system remained intact and not one rock or boulder made it past the safety berm at the bottom of the slope.

Fenner Block Rock Fall Hazard Mitigation 2006

Golden Sunlight Mines

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