Charge Preparation for Blating in Mines

-
In this post we will discuss about the Charge preparation for underground blasting...

For blasting, the charging of hole may consist of one or more cartridge and the separation of cartridge should be least as much possible. Among the charged explosive in a hole, it is necessary that a Detonator is inserted in one of the explosive. The cartridge having Detonator in it, called prime cartridge.
To insert Detonator, a hole is maked with a Pricker of brass or wood.

Insert the Detonator until it is completely buried in explosive after that put back the flap of cartridge and bind the cartridge around with wire to prevent the detonator to come out during charging.

Charging of Shot Holes

Proper charging of shot hole is important to get the desire results. We follows two methods to Charge the holes..

1. Direct Initiation

2. Inverse Initiation


Here we will discuss these two methods..
Direct & Inverse Initiation
Preparation of Shot Hole

Direct Initiation

This is the method of Charging of holes in which the primer cartridge is placed after the other cartridge. So that the business end of detonator is points towards the main body of charge. With this charging the detonator's wave passing towards the back of hole, this increases the chance of maximum explosion.

Advantages
• This is best to prevent fire damp explosion.
• Reduces the blow out of shot hole.
• Provides maximum free face.

Inverse Initiation

When detonator is back of the charge and business end points towards the front of hole, then this charging is called inverse Initiation.
This is not practised in coal faces. But somehow adopted to sum ping or tunnelling and also when delay detonators have to fire a round of shots.
After hole is charged with explosives. Now it's time to stem the hole with stemming material. The stemming material should be compact but plastic in nature, made up of sand and clay in ratio 3:1. The dimension of cartridge is 150 mm to 200mm length and Dia. Of 25-30mm. The first 2 to 3 cartridge stemmed light and rest are tightly with stemming rod.

*If you have any suggestions or question.... Please comment below.


Comments

Post a Comment

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

Know everything about Fire Damp Explosion in Mines

-
Image
Before dealing with Fire Damp.. Here we will discuss About the Definition of Explosion and also we will know about the types of Explosion in Mines. ..So Let's Go... Q.What is Explosion? Ans...:- Explosion can be defined as it the process of sudden change in the volume of any substance instantaneously into gaseous product which produces large quantity of heat energy. Alike above explained, the explosion in mines are of three types. 1. Firedamp Explosion 2. Coal Dust Explosion 3. Water Gas Explosion In this post we will only discuss about "Fire Damp Explosion". 1. Explosion of Fire Damp(Methane) Fire damp is the most common cause of explosion in Coal Mines. The Coal Dust Explosion alone is very rare though it have been initiated by fire damp many times. The explosibility limit of firedamp is between 5.4 to 14.8% in presence of some ignition source and the percentage of Oxygen with respect to Methane percentage. "The maximum explosion
Read more