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Not really my area, so I thought I'd ask the brains trust:
I have a tunnel section of 6m x 8m to be excavated in Granitic material which is likely to be fairly massive. Approx tunnel Length 15km with a mid point adit so each drive is 3-4km. Expectation is that the majority of the drive is Class I requiring minimum support.
My current finger in the air is 6 - 10m/day, but does anyone have any cycle times / excavation rates that I can compare against? There's nothing in the rates area of PP.
I understand some tunneling projects utilise an in-tunnel crusher and conveyors in an effort to boost production. Has anyone direct experience of this?
Much obliged,
G
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Hi Gary
I have no experience of this operation but I would consider the following after the adit has been constructed and the advance chambers have been cleared by rock drills and hand removal.
Both tunnels can be drilled and loaded simultaneously.
A rock drill can penetrate 1m and will probably take 30 mins to drill.
A 6x8 tunnel with drilling @ 2m centres will require 12 drillholes - using two drills = 3hrs drilling.
say an hour to load the charges and safety check plus 30 minutes evacuation = 4.5 hrs per blast.
say 30 mins for dust extraction and return to shaft.
Hand load debris onto conveyor belt 30 mins.
Equals 5.5 hrs per m converts to .18 m per hour x two tunnels = .36 m per hour.
A 24 hour shift will convert to 8.73 m per day - 4.36 m per tunnel.
Trimming and extraction will be concurrent with drilling and charging.
Miners can ride the conveyor before the charging operation and return the same way.
I hope that helps.
Best regards
Mike Testro
Thanks for the link Johannes
An interesting read, but this was constructed using a TBM rather than via drill and blast, so it's not relevant to my tunnel.
Thanks anyway!
G
Hi Gary
This may be interesting link. The Westerscheldetunnel was some years ago built in the Netherlands. The content is in Dutch but with Google translator in should be possible to "read "the document. Very interesting is the production rate of 12 meters per day.
Regards
Johannes
http://www.westerscheldetunnel.nl/nl/over-de-tunnel/tunnelweetjes/tunnel-facts-en-figures.htm
Email: PPadmin@planningplanet.com
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