CONVENTIONAL | DRILL & BLAST
PROGRESS UNDERWAY Spotlights on some projects employing drill and blast method of tunnelling
Hundreds of drill and blast tunnelling projects, large and small, are underway each year across the world. Adits built, cross points and junctions opened up to run multiple advances, then main tunnels are progressed. Caverns are also created, with arch roofs, headings and benches. The method is flexible, adaptable and a variety of
jumbos, ground support and mucking loaders are brought to multiple projects. Here, we sample but a few of the recent works, in
some areas, well aware that so much more is happening - which we are always pleased to hear about.
GERMANY
Hydropower Plant conversion Contractor Porr recently completed a key section of the access tunnel for the Rudolf Fettweis hydropower plant conversion, in Germany. Porr is carrying out the construction works for the
conversion of the run-of-river power plant to a pumped storage power plant. Excavation was completed for the portion of access tunnel that passes under Highway 462. After passing beneath the road, the tunnel divides into the access tunnel and the discharge tunnel.
Porr says half the excavation work in the direction
of the power station cavern has been completed from the intersection of the Schutter tunnel, secondary and access tunnels. Excavation work is being carried out in the secondary
tunnel towards the water storage cavern and in the energy discharge tunnel. The total excavated length of the project is around
5.3km, of which around 4.7km is tunnels. The power plant cavern is approximately 123m long,
20m wide and 42m high. In total, around 400,000m3 is being excavated, of which 200,000m3
is intended for
water storage in the main and secondary tunnels. Construction works started in Q3-’23 and the major
underground hydropower conversion project is due to be completed in 2027. The heritage-protected run-of-river power plant
in Forbach was commissioned in 1914 and converting it to a pumped storage power plant will significantly increase its efficiency. Porr is responsible for the of construction of mined
caverns, water reservoirs and tunnels, the shell of the power plant cavern, construction of two pressure shafts, and foundation engineering work.
Above: Porr has completed excavation of the access tunnel section under a highway for a hydropower plant conversion in Germany PHOTO CREDIT: PORR
February 2025 | 17
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