System Description

UTM-00355 | Rev 2
Page 252 of 261
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Lowering Detonators into Drilled Holes
When lowering booster down the drilled hole it is important to note the following:
 Pillow loading is advisable to prevent the down-line wire being exposed to unnecessary tension when
augering explosives down the hole. It also helps to prevent the down-line wire being damaged when the
booster strikes the bottom of the hole.
 When lowering the booster down the drilled hole, hold coil in one hand and use the thumb and forefinger of
the other hand to guide the booster down the hole. At the same time uncoil the helix that is formed in the
cable during coiling.
 When the booster hits the bottom of the hole, raise it off the bottom and tighten the cable to ensure that no
kinking or coiling of the down-line wires has occurred in the hole. Kinking/coiling could cause damage
during loading or slumping.
 There are two schools of thought on how to tie the down-line wire to the stake that must always be placed
in line with the row of holes as follows:
 The first one is to take the down-line wire protruding from the hole and coil it three or four times around the
stake, leaving sufficient slack on the fourth coil to pull the coil through the loop and then carefully tighten the
down-line wire without causing any sharp kinks in the cable.
 The second one is advisable in areas that are known for slumping of holes. Treat same as above with the
exception that instead of using the down-line wire protruding from the hole, place the remaining coil next to
the stake and then coil a sufficient length from the connector side and tie in same manner as above,
ensuring that tension is exerted on the down-line wire and not on the connector interface by allowing
sufficient slack between knot and connectors. It is believed that if slumping appears, the down-line wire will
have sufficient slack in the coil to compensate for the slumping without the wire pulling directly on the stake.
Both methods as described above have been successfully deployed globally.
E NSURE THAT CONNECTOR IS PROPERLY CLOSED TO PREVENT INGRESS OF MOISTURE AND DIRT .
Charging of Drilled Holes
When charging drilled holes, it is important to keep the following in mind:
 Ensure that the connector is properly closed to prevent ingress of explosives which could result in the
corrosion of tines inside the connector. Corrosion of the tines will cause increased resistance during
blasting.
 If Pillow loading was not done during auguring, lift the booster an appropriate distance from the drilled hole
bottom and keep the down-line wire tight to prevent it from kinking. Kinks in the wire can lead to pocket
loading of the explosives; these pockets will, through time, slide down the hole and cause insufficient
explosive charge per hole. Kinks may also lead to damage of the inner cores in the downline if tension is
exerted on the downline wire. On completion of charging, ensure that connectors are properly closed and
ensure that the down hole lead is still tied to the stake
 If Pillow loading was done, keep down-line wire tight to prevent kinks from forming inside the hole and keep
down-line wire towards middle of the hole to prevent the charging hose from pushing the down-line wire
against rock surface of the hole which might result in down-line wire damage. Ensure that the stake is still in
place and connector still closed.