Drilling Patterns

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Before firing a shot, it is important to drill holes and drill holes are followed by different Drilling Patterns. The selection of Drilling Patterns are different to satisfy the different conditions. So now we will know the different Drilling Patterns which are used(one by one).
• Drilling Patterns are also known as shot-hole patterns.

1. Pyramid or Cone cut :-  In this type of drilling the pattern of holes something alike pyramid or cone.
Pyramid cut involves the drilling of holes in centre and also at the side which meet at a point at the back.
Now in modern design of cone cut involves in forming of polygon, in this also holes meet at a point with central hole.
It's depth is restricted up to 60% to the width of drift.

2. Drag Cut :- It is used for smaller drift of 1.8m to 2.4m width. By making the angle so that the strata breaks along to cleavage plane.

3. Wedge Cut :- In this cut holes are drilled, whose angles are less than 45° and the centre meet along a line at back.

4. Fan Cut :- The fan cut is employed for thin layer of strata which are mostly soft. It is done by forming fan like structure and the charging in each hole is heavy.

5. Burn Cut :- In this cut the holes are drilled at right angle to face in a cluster manner. Some holes are left uncharged which provide space for heavy charge hole.
The supervision is easy and also time saving.


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