Installing the 3TB in a borehole
8. Fix the signal cable to the main lifting cable about one meter above the strain
relief mechanism using a cable clamp (a nylon cable tie may be sufficient for
shallow installations). Leave a little slack in the signal cable between the
clamp and the strain relief mechanism.
9. Position the assembly over the top of the borehole. Do not allow it to drag
across the ground.
10. Lower the sensor so that its base is level with the borehole mouth. Set the
depth gauge on the winch to zero.
11. If using a baffle, as described in section 3.6 on page 20, fit it now, half-way
between the sonde and the strain-relief.
12. Calculate how much lifting cable must be lowered into the borehole, taking
into account the length of the sensor and the strain relief assembly or
digitizer.
Note:
If you are installing a 3TB in a deep borehole, the
weight of the sensor will stretch the load bearing cable
slightly. Remember to allow for this when raising or
lowering the cable in the following steps.
13. Begin lowering the sensor down the borehole, keeping track of the depth
reached.
28
Issue G - November 2019
