Tunnel construction machines have to meet huge demands. Especially confined spaces and the resulting low height of the material feed present a great technological challenge. Safety aspects, a fully electric drive system and dust reduction play an important part, too.
The mobile track-mounted jaw crusher STE 100.65 TV PB optimally fulfils all these requirements. And the SBM plant used for the Albula Tunnel construction excels due to its compact dimensions of 19 m length, 2.65 m width, 4.2 m height and a weight of 57.5 tons. The especially low feed height of 2 m allows simple and easy material feed by wheel loader in the tunnel.
The new construction of the 5860 m long Albula Tunnel is carried out by drilling and blasting. To allow removal of the excavated material by conveyor belts the pieces of granite/dolomite have to be pre-crushed to 0-150 mm. This challenging task is performed directly in the tunnel by the two SBM crushers on tracks. Then the pre-crushed material is efficiently and economically removed by conveyor belts that are up to 3 km long.
This is no problem at all for the power plants. They are designed for fully electric operation by powerful 132 kW three-phase squirrel cage motor and offer a throughput capacity of up to 250 t/h each.
Smooth Operation due to Intelligent Systems
The power pack is equipped with the single toggle jaw crusher STE 100.65 HBSV mastering material feed sizes up to 700 mm at a material feed opening of 1000 x 650 mm in the Albula Tunnel. The integrated hydraulic gap adjustment (Gap Release Control) prevents that unbreakable parts damage the crusher and ensures smooth crushing. The acting forces are measured directly at the crushing jaw - if the predetermined limit value is exceeded the crushing gap opens automatically and resumes the predefined normal position.
To ensure smooth operation of STE 100.65 TV PB, SBM has installed an apron feeder as well as a special pre-screen with the dimensions 1500 mm x 1000 mm that increase the performance of the machine by 30 % and ensure constant transportation of the end material.
A strong over-band magnetic separator prevents damages to the up to 3 km long belt conveyors in the tunnel and resulting standstills caused e.g. by metals parts broken off from machines.