MREL DATA TRAP II Operation Manual Download Page 38

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DataTrap II™ Operations Manual - Edition 5.4

should be “shielding to shielding” and “center to center”. Ensure that the center conductor and the shielding conductor do not touch
each other across the connection.

10. Place the

DataTrap II™

Data/VOD Recorder

in a protective shelter and/or a safe distance away from the blast area as dictated by

flyrock. This distance may be closer than what is considered safe for the User. When set, the

DataTrap II™

Data/VOD Recorder

does

not require a User to collect the data; the

DataTrap II™

Data/VOD Recorder

records the data automatically.

11. Run the coaxial cable from the

PROBECABLE

to the

DataTrap II™

Data/VOD Recorder

. If necessary, shorter lengths of coaxial

cable may be connected together using the wire cutters and electrical tape to make a longer length of coaxial cable. Somewhere
along the length of the coaxial cable, loop the coaxial cable around a large rock. When the blast is fired, and the ground moves,
looping the coaxial cable around a large rock will stop the blast from pulling the coaxial cable and the

DataTrap II™

with the blast.

Alternatively, leave sufficient slack in the coaxial cable to allow for ground movement.

12. A male

BNC

connector should be attached to the end of the coaxial cable that is to be attached to the channel inputs (

labeled 1 2 3

4 5 6 7 8

) on the back of the

DataTrap II™

Data/VOD Recorder

. Convenient

BNC Adapters

have been supplied with the

DataTrap II™

Data/VOD Recorder

for this purpose. The

BNC Adapters

should be connected to the coaxial cable using the wire

cutters and electrical tape. The connection should be shielding to shielding and center conductor to center conductor. Ensure
that the center conductor and the shielding connections do not touch each other. It is a good idea to check the total resistance of
the

PROBECABLE

and coaxial cable circuit at the

BNC

connector using a blaster’s galvanometer to ensure that there are no bad

connections.

13. At the

DataTrap II™

Data/VOD Recorder

end, connect the coaxial cables to the input connectors (

labeled 1 2 3 4 5 6 7 8

) located on

the outside and at the back of the

DataTrap II™

Data/VOD Recorder

14. The

PROBECABLE

installation aspects of the test are complete. The

DataTrap II™

Data/VOD Recorder

is now ready to be prepared to record the

test as detailed in

Chapter 4.6

5.5 ProbeCable And Coaxial Cable

Protection

It is important to protect the

PROBECABLE

and the coaxial cable from damage

caused by personnel and machinery operating on the blast. It is also important to
protect the

PROBECABLE

from damage caused by detonation of other holes and/or

surface accessories such as detonating cord, detonating relays, and shock tube bunch blocks.

The cables may be protected in many ways. It is best to lead the

PROBECABLE

and coaxial cable under the detonating cord and leave

a barrier of sand or drill cuttings between the cables and the detonating cord. A danger point is the collar area of the holes as the
detonating cord or shock tube bunch blocks that initiate the downlines may cross directly over the

PROBECABLE

or coaxial cable. A good

procedure is to protect the area where there is a cross over for about 1.5 m (5 ft) along the length of cable. Experience has shown that a
sand or stemming barrier thickness of 15-30 cm (0.5-1 ft) is sufficient to protect the cables.