Drilling Patterns

-
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.


Popular posts from this blog

Secondary Blasting Technique

-
Image
In this post we will deal about the Definition of Secondary Blasting and types of Secondary Blasting . Some other Blasting are also available you can read about that. So let's start... Definition of Secondary Blasting The technique used to blast the boulders to achieve the fragmentation is called secondary blasting. This blasting is done to get the rocks which can be easily handled. Why and how to do secondary blasting? Why secondary blasting? We does secondary, in case when the primary blasting don't give fragmentation of rock which can be easily handled. The secondary blasting is followed after the primary blasting. How to do secondary blasting? To do secondary blasting we have to follow some methods which will give us batter resultant. These are here 1. Plaster shooting or Mud Capping.. As name indicates mud capping, the primer cartridge is place at top of Boulder and covered with mud. The blasting is done from the safe place by electric detonator
Read more

Bord and Pillar Method

-
Image
Bord and Pillar Method of mining involves in the formation of roadways and the development of Mines. The first stage of working of Bord and Pillar Method is Called Development. In the development stage parallel roads are driven nearly at right angle to the first set. These roads are also use to join the separated coal blocks. The network of roads regularly increases as development of the mine. The second stage of working of Board and Pillar Method  of mining is called Depillaring. The Depillaring can be understood by It's name(De-Pillaring). In Depillaring the working involves in the extraction of coal from the Pillars. These are two stages of this mining method. The another name of Bord and Pillar method is "Pillar and Stall". For the application of Bord and Pillar Method there are some conditions to be full filled. Conditions are.... •The thickness of seam seam should be more than 1.5m. •There is less amount of dirt bands present in seams. •Se
Read more

Shaft Sinking

-
Image
Q. What is shaft? Ans. :- It is a vertical or inclined entry made to touch seams. The word shaft is used for underground mining entrance. Q. Why shaft? Ans.:- The shaft is excavated after getting approval to mine the mineral bed by underground method of mining. Simple View of Working Shaft Shape of Shaft Generally the shaft are of circular in shape but in some mines it is of rectangular in shape. The circular shafts are best because they resist heavy side pressure and offers least rubbing surface area for ventilation. Bricking and concreting job are easy and diameter of these shaft may be varies from 4.2mts to 6.7mts. ◆The shaft sinking process is costliest and time taking process. So it is necessary to drill pilot hole within the radius of 50m of main shaft which has to be drill. This pilot hole give us an idea about the rock and how we have to encounter those problem which will we face during shaft thinking. From this we will get a data about                      1
Read more