Underground Survey

Guys,
In this posting I gonna explain about Tunnel Surveying which I only ‘try’ joining surveyor for a few fields as built (you know what I mean? Don’t trust my posting bellow completely). This job is really different with the other survey activity, because the surveyor here has to deal with confined space, and absolutely deal with very short sight. Surveyors are used to carrying a lot of stuff. To do our work efficiently we need plumb bobs, prisms and plumbing poles, measuring tapes, paint, stakes, hammers, field books, calculators and data collectors, transit, Total Station, tripod, radios...
From the office usually we are use to using Mine Cat, an underground equipment for carrying crew to the heading/face tunnel with basket boom for reaching some high level in addition the UG survey activity need it.

In here, actually has general standard survey methods, there are: Geodetic Standard Local Stations & Bench Mark, Permanent Survey Station (PSS) Establishment, Projection Scale Factor, Networks, tolerance on progression, Horizontal Angular Closure Tolerance, and Horizontal Closure Tolerance.

Common survey activity in UG are:
1.1. Survey Face Marks
· New Excavations: All new excavations will be marked by surveyor in red paint, consisting of left rib, centre line, right rib, grade line across the face @1.5m above design floor, back sights marked on opposite rib. The centre line will also be painted across the backs with the high is able to be reached with a paint pole.
· 2nd Advancement: After firing and screening the first round, surveyor will mark up the next as per a new excavation extending the center along the backs.
· Recording: All excavation marks made by survey will be recorded and checked against the design, before the excavation can be blasted.

1.2. Drift Lasers
· McGarf Laser: The McGarf laser will be installed where every practical to provide line and level for the jumbo drill development crews.
· Standards: The standard positioning of the laser will be nominally at 1.5m to the design floor and 1.0m from the left drift.
· Blasting: The McGarf laser will only be installed after the blasting face position is greater then 8m from the installation position.
· Checking: The laser direction will be checked by PTRI survey after every 20m of development.
· Accuracy: The McGarf lasers will only be used for drifts less than 60m in length, lasers alignment can not be guaranteed after this distance.
· Testing: A baseline of >30m will be established near the Big Gossan workings for the checking of all McGarf Laser before use. All lasers will be checked and certified by the PTRI surveyors and recorded on a monthly basis.

1.3. Daily Survey Control
· Main Headings and Secondary Headings. The Survey Crew will get heading advancement of all blasted faces in the previous 24hrs;
· As Constructed Surveys. Survey will use a Total Station to scan the face, back, floor and ribs on a regular basic, with advancement not exceeding 20m;
· Profile Survey of the heading face. The profile survey will be completed during the as constructed survey period;