9781439834220.ch10

Large tunnels and openings can be subdivided and

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Unformatted text preview: utdown; and this feature enable its use in the changing rock conditions. Large tunnels and openings can be subdivided and excavation activities can be carried simultaneously in these sections/divisions. Low Investment : Compared to the TBM, for the similar size of cross-section; the investment costs for roadheaders amount to be approximately 0.15 (large sections) to 0.3 (small sections). Since they are available on rent basis, as such, they can be used even for small projects. Quick and Easy Mobility: Comprehensive assembled equipment and chambers are not required. Delivery time is usually 3–6 months, and immediate after the delivery they can be brought into operation. 10.6 IMPORTANT DEVELOPMENTS Alpine Miner Tunneller AMT 70 has been specially developed for NATM.11 NATM uses the techniques and equipment that can produce high quality excavations in soft ground and adverse conditions. This unit has special features to excavate tunnels of the size 60 m2 or more. Use of water jet operating at pre...
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This document was uploaded on 02/12/2014.

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