Refer to
Preparing the Job Site and the
for instructions on preparing
the job site and the machine.
4.
Drill the bore.
Drill the bore in 3 stages:
A.
Entry
In the entry phase of the bore, push the drill
bit and head into the ground at an angle
of up to 16 degrees. After pushing in one
or more pipes, begin drilling down and
forward until you reach the desired depth or
depth-gauge hole (if used).
B.
Horizontal Reach
After reaching the desired depth, push the
bit forward, steering the bit to a horizontal
depth. The sonde emits a radio signal
from the sonde housing, allowing the
locating-equipment operator on the surface
to track the location and depth of the head
using the sonde receiver as you drill and
steer it along a planned path..
C.
Exit
Once you have attained the planned
horizontal reach, steer the head up at an
angle, similar to your entry angle, bringing
the bit into the exit hole or trench.
Refer to
Drilling the Bore (page 57)
.
5.
Backream the bore and pull back the cabling
or pipe.
After entering the exit hole, a crew member
detaches the drill bit and sonde housing from the
drill pipe. Attach a reaming bit and the end of
the cable or pipe to be pulled through the bore.
The reaming bit is designed to enlarge the bore
as you pull it back. Pump drilling fluid through
the pipe to the reaming bit as you pull the cable
or pipe back through the bore to lubricate the
reamer and allow the cable or pipe to slide easily
through the bore. Continue pulling the pipe back
until the reamer reaches the depth-gauge hole
or exits at the entry point. Remove the reamer
and product from the drill pipe, pulling the pipe
the rest of the way back to the machine.
Refer to
Backreaming and Pullback (page 60)
for instructions on backreaming and pulling
cable or pipe.
6.
Finish the bore and leave the job site.
After completing the operation, disconnect and
clean the machine, and load it on the trailer;
refer to
Finishing the Job (page 63)
.
Gathering Site Information
Planning the Initial Path
Before drilling, plan the path you will bore and prepare
as follows:
•
Create a basic plan for the bore, mapping out the
proposed path.
– Note any obstacles which may affect the bore
such as large trees, bodies of water, buildings,
etc.
– Plan the path of the bore to avoid as many
obstacles as possible.
– Determine the depth of any bodies of water to
be crossed to ensure that you can get deep
enough to go under them.
•
Determine the depth you need to install the
material at and the minimum bend radius of both
the drill pipe and the material being installed. This
will affect how long the bore needs to be and
at what angle you can enter and exit; refer to
Planning the Bore Path (page 39)
.
•
Have the area of the bore path marked for utility
lines (in the US call 811). Ensure that all lines are
marked on your blueprints/bore plan as well.
•
Contact the local authorities to arrange for any
permits and traffic control that you will need to
conduct the job.
Inspecting the Proposed Job Site
Physically inspect the site as follows:
•
Note the terrain, slopes, valleys, hills, and any
features not planned for previously.
Determine the degree of slope at both the
proposed entry point and exit point.
•
Determine what the soil types are in the area and,
if possible, and what they are at the depth you
will be boring. You may need to dig test holes at
intervals along the bore path to fully determine this.
•
Walk the area of the bore path looking for
any possible unmarked obstructions. Look for
manholes, pedestals, old foundations, etc.
•
Identify all hazards of which you will be passing
within 3 m (10 ft).
Common hazards include the following:
– Gas lines
– Electrical power lines
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