Commonly known as DTH, the Down-the-Hole Hammer drill is a
percussive device in cylindrical form with integral drill bit that is fitted
directly onto the bottom of a drill string. Technical Data used in the field
explained in drilling courses in Rawalpindi.
DTH is one of the most efficient ways of
drilling rock, using a rapid hammer action to break the rock into sizeable chips
which are then evacuated from the bore hole by the air exhausted from the DTH
Hammer. The technique provides fast drilling of accurately aligned, straight
and clean holes in most ground conditions.
It is important to remember in rock extraction that blasting
is the first phase of crushing. It is therefore vital that time and effort is
spent on ensuring that the hole size, overall blast design and explosive
loading is appropriate for the conditions, in order to achieve good
fragmentation, optimum productivity, safe stable faces and level floors at
minimal cost. Some more details of drilling courses in Rawalpindi are
as under.
Jack hammers were used for springing, stopping and popping.
Although they were lightweight, portable, easily maintained and inexpensive,
they were essentially labor intensive, low volume producers, resulting in small
holes and limited control, as well as presenting significant health and safety
issues.
The cable tool was primitive and used a heavy bar with a
chisel, suspended on a wire rope that was then mechanically dropped on the rock
to crush it within the hole, using water to bale clear the resultant cuttings
and dust. Again easy to use, simple to maintain with low cost operation,
minimal dust and effective in bad ground, but the cable tool was slow and
limited to larger holes, with no alignment control. It required a regular water
supply, two man operation and was really only of use for soft to medium rock
formations. TSK Training for Skills and Knowledge is the best institute in
Rawalpindi Islamabad for Pakistani Students who wants to join drillingcourses in Islamabad.
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