Hand mining is a trenchless construction method used to install utility tunnels larger than 48‐inches in diameter to allow for personnel entry for manual excavation with hand tools at the tunnel face. This construction method requires non‐pressurized and reasonably stable soil for safety. A great advantage to hand mining is the ability to remove obstructions at the tunnel face as they are encountered along the alignment.
A forward shield often includes a steering joint for line and grade control, which can be adjusted after referencing the pre‐set tunnel laser’s current position. In slightly unstable ground conditions, the shield is outfitted with a hood or overhung shelf that mitigates the natural angle of repose of the soil, minimizing subsidence. Manual labor is required to remove material at the tunnel face while excavated soil is removed from the tunnel by an electrically driven haul unit/muck cart system.
Similar to pipe jacking, the tunnel is advanced by hydraulic thrust cylinders in the launch shaft. In the pipe jacking mode, the prefabricated jacking pipe such as steel casing, reinforced concrete pipe (RCP), or other common jacking pipe materials is used. Hand mining operations can also be advanced by hydraulic cylinders directly behind the shield to install a temporary structure such as liner plate, rib, and board or even box shape tunnels.
To learn more about hand mining and the Akkerman equipment available for the process, please see the website’s equipment section. Our knowledgeable sales team is always available to answer any questions you may have or discuss your next project’s equipment options.