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The following example illustrates the process given an installation using the machine at an 18% pitch on
level ground:
1. 18% pitch
2. 53 cm (21 inches)
•
You insert the first 3 m (10 ft) of drill bit/pipe into
the ground with no steering. The end of the drill bit
is 53 cm (21 inches) deep
•
You begin steering up for the next 3 m (10 ft),
pushing the pipes in at the maximum pitch change
of 8%. This results in a change of pitch from 18%
at the beginning of the 3 m (10 ft) to 10% at the
end of the 3 m (10 ft) for an average pitch of 14%.
Given that, the drill head lowers another 43 cm (17
inches) and is now 96 cm (38 inches) deep.
•
Continuing steering up for the next 3 m (10 ft) at
an 8% pitch change, your pitch changes from 10%
to 2% for an average pitch of 6%. Given that, the
drill head lowers another 18 cm (7 inches) and is
now 114 cm (45 inches) deep.
•
Leveling the drill head from 2% to 0% takes less
than 1.5 m (5 ft) more for a final depth of 119 cm
(47 inches). Reaching this final point took 3 and a
half, 3 m (10 ft) pipes. So for this example, your
entry point should be 10.6 m (35 ft) back from the
beginning-at-depth point of your installation.
Important:
You can use the information contained
in this section to determine both the space needed
to steer up to the exit point if needed and also to
steer around obstacles.
Figure 45
3. 96 cm (38 inches)
4. 114 cm (45 inches)
(Figure
45).
5. 119 cm (47 inches)
6. 10.6 m (35 ft)
Mapping the Bore Path
With the information you gathered previously, map out
the path of the bore, identifying the following so that
you can mark the site later:
•
Entry point
•
Location of the machine and supporting equipment
•
Beginning of bore-at-depth
•
Any obstacles that you need to steer around and
the locations where you need to start steering to
get around or under them
•
Any utility lines you will need to cross
•
Slope and soil changes along the path that will
affect the bore
•
End of the bore-at-depth
•
Exit location if it is different than the end of the bore
43
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