MANUAL – REFLEX EZ-TRAC™ | 81
Should it be necessary to perform open hole surveying, check the
borehole with a dummy probe first. This will give you information
about the hole condition and if the recorded hole depth is correct.
Taking this step can avoid the possible loss or excess damage to the
equipment.
11.2.5.1 Downwards direction
For boreholes that are directed downwards, gravity can be used to
lower the survey system. A swivel with a wireline and a winch is
normally used to recollect the system. For short holes, a marked rope
or wire can be used.
The survey system for surveying downwards in an open hole consists
of the
REFLEX EZ-TRAC™ instrument, three aluminium extension rods
and a swivel.
Open hole downwards
1. Thread the swivel into the box end of the aluminium extension rod
and tighten with pipe wrenches.
2. Make sure that the wireline cable goes through the swivel eyelet
and that it is secured.
3. Gently place the survey system at the collar of the hole.
4. Using the wireline winch and a counter or marked wireline, slowly
lower the survey system to the survey station.
5. Keep the survey system stationary at the survey station until the
measurement has been taken.
6. Using the wireline, slowly raise the survey system until it reaches
the collar of the hole.
7. Gently lift the survey system from the hole.
8. Place the survey system in a safe position away from the
borehole and unthread the running gear.
11.2.5.2 Upwards direction
For boreholes that are directed upwards, a set of rods must be
attached to the survey system to allow the instrument to be pushed in
and pulled out of the hole.
Drill rods, wood rods, coiled plastic hose, coiled tendon or any other
suitable push rods may be used. If any of these are of ferrous steel,
non-magnetic aluminium extension rods have to be used.
The survey system for surveying upwards in an open hole consists of
the
REFLEX EZ-TRAC™ instrument, three aluminium extension rods (if
the push rods are of magnetic material) and an adapter that will allow
the system to be threaded to the push rods.
Open hole upwards
1. Thread the adapter into the box end of the aluminium extension
rod and tighten with pipe wrenches. If the push rods are of non-
magnetic material, the adapter can be threaded directly into the
top coupling of the instrument.
2. Gently place the survey system at the collar of the hole.
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