In addition to hazards associated with pit wall stability, subsidence is also a significant concern when working near historic mine workings. It can be triggered by ground thaw, heavy rain and nearby pit blast vibrations.
Areas where subsidence is anticipated are typically identified by physical barriers (such as temporary berms) and delineator cones and pickets. Safety procedures at the mine dictate which areas can be accessed and what precautions are required.
The design and stability of open pits developed through historic underground workings are influenced by “typical” factors, such as rock mass and structural characteristics, and by “atypical” factors in the form of underground mine workings.
To anticipate and mitigate risks, voids intersecting the pit wall and floor are identified, defined and assessed. Pit designs are adjusted around anticipated and intercepted workings, and revised designs may require ground support.
If you are looking for solutions to your open pit challenges, we can help! Reach out to our rock mechanic experts.