Blasting Mining

Blasting in mining is blasting activities are conducted for the breakdown or divorce of a material's disarray (rocks) using explosives or an explosion process. Explosives are chemical explosives meant is defined as a single chemical compound or a mixture of solid, liquid, or mixtures thereof which, if given the action of heat, impact, friction or initial explosion will experience a very rapid exothermic chemical reaction and the reaction results in part or entirely gaseous accompanied by very high heat and pressure which is chemically more stable. Heat from the gas produced detonation reaction is approximately 4000 ° C. As for the pressure, according to Langerfors and Kihlstrom (1978), could reach more than 100,000 atm or equivalent 9850 MPa (»10 000 MPa). While the energy in units of time which caused about 25,000 MW, or 5.95 million kcal / s. It should be understood that the energy is so great it's not really reflect the amount of energy stored in explosives so great, but this condition occurs due to blasting a very fast reaction, which ranges between 2500 - 7500 meters / second (m / s). Therefore, the energy force only happens a few seconds which gradually decreased with the development of rock collapse.

Classification Of Explosives

JJ Manon in 1978 to clarify the source of explosive energy is divided up based explosives mechanical, chemical, and nuclear). Because the use of chemical explosives larger than other energy sources, then the classification is more intensive chemical explosives allowed. Consideration of its use among other things, the price is relatively inexpensive, technically easier handling, more variation delay time (delay time) and compared with nuclear dangers lower. Permissible explosives in the above classification needs to be corrected because the current blasting material is largely a powerful explosive. Permissible explosives used exclusively for the scattered coal mined underground coal blasting agent and the type is classified as strong explosives

Presently there are various way of classifying chemical explosives, but in general the rate of reaction is the basis for such classification. Examples include the following:

* According R.L. Ash in 1962, chemical explosives are divided into: 

1. Powerful explosives (high explosive) if you have properties with a velocity of detonation or explosive reaction between 5000-24000 fps (1650-8000 m / s)
2. Explosives weak (low explosives) if it has properties deflagrasi or burning reaction rates of less than 5,000 fps (1,650 m / s).

* According to Anon in 1977, chemical explosives are divided into 3 types as shown in  

TYPE	REACTION	EXAMPLE
Low Explosive	Deflagrate ( Burned )	Black Powder
High Explosive	Detonate ( Explode )	NG, TNT, PETN
Blasting Agent	Detonate ( Explode )	ANFO, Slurry, Emulsion

Reaction And Detonation Products 
Blasting will give different results than expected because it depends on external circumstances when the work is done that affects the quality of forming chemical explosives. The heat is beginning the process of forming a chemical decomposition of explosives which caused combustion, followed by deflragrasi and final detonation.
The process of decomposition of explosives is described as follows:  

• Combustion is an exothermic reaction surface and its continuity is maintained by the heat generated from the reaction itself and its products in the form of the release of gases. Combustion reactions require the element oxygen (O2) both contained in the wild or from molecular bonding materials or materials that burn. To stop the fire enough to isolate the burning material from oxygen. Examples of reactions diesel oil (diesel oil) are burned as follows:

CH3 (CH2) 10CH3 + 18 ½ O2 ® 12 CO2 + 13 H2O 

• Deflagrasi is exothermic chemical process in which the transmission of the decomposition reaction is based on thermal conductivity (heat). Deflagrasi is the phenomenon of surface reactions whose reaction increased to blast and shock waves in shock wave) with a low propagation velocity, which is between 300 - 1000 m / s or lower than the speed of sound (subsonic). For example in the detonation reaction low explosives (black powder) as as follows:

Potassium nitrate + charcoal + sulfur
20NaNO3 + 30C + 10S ------> 6Na2CO3 + Na2SO4 + 3Na2S +14CO2 + 10CO + 10N2 

  

Sodium nitrat + charcoal + sulfur
20KNO3 + 30C + 10S ------> 6K2CO3 + K2SO4 + 3K2S +14CO2 +10CO + 10N2 

• The Explosion, according to Berthelot, is instantaneous rapid expansion of the gas becomes larger than the previous volume the sound of loud and destructive mechanical effects. From the definition, it can be implied that the blast did not involve a chemical reaction, but its appearance is caused by energy transfer to the mass movements that cause the effects of heat and mechanical damage with a loud noise. Examples include explosions continue blown rubber balloon eventually burst, fuel tanks exposed to continuous heat can explode, etc.

Detonation is the chemical-physical processes that have a very high reaction rate, resulting in very large gas and temperature which are all built in a very large expansion as well. Reaction rate is extremely high heat to distribute pressure throughout the blasting zone in the form press the shock wave (shock wave compression) and this process continues to deliver energy to end up with the expansion of the reaction. The speed of propagation reactions in the process of detonation is between 3000 - 7500 m / s. Examples of ANFO reaction speed of about 4500 m / s. Meanwhile, shock wave compression has a very high thrust and capable of tearing a pre-existing cracks become bigger cracks. In addition symphatetic shock wave can cause detonation, and therefore very important role in determining the safe distance between holes. Examples of detonation process occurs on the type of blasting materials, among others:  

* TNT : C7H5N3O6 ------> 1,75 CO2 + 2,5 H2O + 1,5 N2 + 5,25 C

* ANFO : 3 NH4NO3 + CH2 ------> CO2 + 7 H2O + 3 N2

* NG : C3H5N3O9 ------> 3 CO2 + 2,5 H2O + 1,5 N2 + 0,25 O2

* NG + AN : 2 C3H5N3O9 + NH4NO3 ------> 6 CO2 + 7 H2O + 4 N4 + O2 

By knowing the chemical reaction in the detonation is expected participants will be more careful in dealing with chemical explosives and know the names of the gases of explosion and danger.

Some Terms In The Explosion:  

•  Explosion of refraction (refraction shooting) is an explosion in the hole or shallow wells to cause vibration for how seismic refraction geophysical investigations.
• Explosion of blasting boulders are secondary to chunks of rock size reduction by making a small-diameter hole and shoot a little filled with explosives
• Blasting in the air (water shooting) is way cause seismic energy in the earth's surface by detonating explosives in the air 
• Blasting off the turn (off-shift blasting) is Blasting is done outside working hours cultivation
• Blasting holes in the (deep hole blasting) is a way ladder quarrying or mining blasting open using a deep shot holes adapted to high levels of
• Trench blasting is blasting in the manufacturing process of the trench
• Muffled blasting (cushion blasting) is a way to make blasting the air cavity between the explosives and explosive plugs or make a hole shot larger than the diameter lunkhead resulting in a relatively gentle vibration