Stone Quarrying (Blasting)

Blasting 💥💥💥

Tools for blasting 

Blasting operations can not be carried out without certain tools, which are as follows:

1. Dipper

For creating a drill hole up to required depth we need dipper as shown in figure below.

DIPPER

2. Jumper

Jumpers are used to make blast holes. It look likes as below.

JUMPER

3. Priming needle

Priming needle used to maintain the hole when tamping is being done.

PRIMING NEEDLE

4. Scraping spoon

Scraping spoon used for removal of dust from blast holes.

SCRAPING SPOON

5. Temping bar

Temping bar used to temp the material while refilling the blast hole.

TEMPING BAR

Materials for blasting

1. Detonator

Detonator it self is not an explosive, it is a small explosion cap which is used to triggered explosive for blasting operation. It is in the form of copper cylinder having diameter 6 mm and length 25 mm. It is closed at one end and contains 6 to 9 grains of fulminate of mercury. This detonator is used when dynamite is used for explosion. Detonators are fired by chemically, mechanically or electrically. generally this detonators are fired by fuse or electric spark.

2. Explosives

Commonly used explosives are dynamite and blasting powder. Blasting powder is also known as gun powder, gun powder is a mixture of  charcoal(15%), sulphur(10%) and saltpetre (KNO3)(75%). sometimes saltpetre is substituted by chile saltpetre (NaNO3), but it absorbs moisture so it is difficult to stone it for longer time. 

Composition of  dynamite is 75% of nitro-glycerin and 25% saturated sandy earth.

Comparison of blasting powder and dynamite

Blasting powder	Dynamite
Large blocks obtained	Small blocks obtained
Cheap	Five times costlier
Destruction is weak	Destruction is strong
1 kg powder loosen 4 m3 of rocks	1 kg dynamite loosen 6 m3 of rocks
Required hard temping	No requirement of hard temping
Used for ordinary works	Used for important works like tunnelling, mining and quarrying under water

List of few explosives which are used for blasting:

• Blasting gelatine
• Cordite
• Gelignite
• Gun cotton
• Liquid oxygen
• Rock - a - rock

3. Fuses

Fuses are required to ignite explosives from a distance or delay. They are in the form of small rope of cotton with the core of continuous thread of gun powder. Good fuses are fired at a rate of one centimetre per second. Only patented electric fuses are allowed to use for blasting.

FUSE

"To Be Continued..."