Tophammer drilling is a percussive-drilling
method, the percussion mechanism is located on
the drill rig, i.e. outside of the hole and
conventional tophammers dominate the 28 mm to
140 mm hole-range.
To drill holes of greater
depth, extension rods are added in front of the
rock drill until the final hole-depth is
Since each extension-rod must be joined
with the next, a threaded union is needed
between each rod. In each such joint in the
drill-string, impact energy is lost. The loss
per joint is equal to between 4 and 6 per cent
of the value of the impact energy before the
The exact value of the energy loss
depends on the design of the joint. The greater
the mass of the joint, the greater the energy
loss. If the joint is not properly tightened,
the energy loss can be as much as 10 per cent.
In long-hole drilling underground,
(and therefore many) rods are used, about half
the impact energy can be lost.
Secoroc ThunderRod T60 system:
Our tophammer family
welcomes a new arrival.