When Skyline Construction, Inc. concluded that traditional excavation
methods were not feasible to reach a deposit of high-quality
limestone, they assembled a team of experts to design a New
Austrian Tunneling Method (NATM) underground passage.
A team of experts, headed by Peter Kolitch & Associates,
was assembled to design the adit, specify the required construction
products and construct it using NATM techniques. Kristian Loevlie
of Shotcrete Technologies, Inc. was chosen to be a member
of this team because of his extensive experience with NATM projects,
shotcrete applications, and the formulation of shotcrete design
mixes. In addition, Shotcrete Technologies, Inc. supplied the
accelerators, superplasticisers, and retarders that were used
in the project.
The adit was excavated using an Alpine Miner AM 50-P roadheader
supplied by AMS Technologies. This unit, propelled by a crawler-system,
utilizes a cutter boom outfitted with a rotating cutting system
that features replaceable cutter teeth for aggressively digging
into the ground at the heading. As the tunnel is excavated,
it is immediately supported with a system of lattice girders,
welded wire fabric, rock bolts, and 2 inches of shotcrete.
For shotcreting, a Shotcrete Technologies robotic arm
unit was fitted onto a Belarus front-wheel-assist farm tractor
equipped with a 59 horsepower engine. The three-sectioned telescopic
boom is hydraulically actuated. With a remote control unit,
the nozzle operator can precisely direct the nozzle anywhere
towards the back or sides of the decline for applying the shotcrete.
The use of the NATM method combined with the products and experience
of Shotcrete Technologies allowed a high quality limestone deposit
to be reached in a safe and cost-effective manner while avoiding
cost-prohibitive conventional methods.
For additional information about this or any other projects,
please call Shotcrete Technologies at (303) 567-4871 or send
an e-mail request with name and address to firstname.lastname@example.org.