Blasting activities at the mine is one of the activities that are deemed to have a high enough risk. But that does not mean those activities can not be controlled. Process control these activities can be started from the process of mixing explosives ingredients, the process of filling the holes with explosives into explosive, stringing process and firing process.
In this case an important role is to control the firing process. in a blasting operation was preceded by drilling in the mining that aims to make the hole shot. Bullet hole itself will be filled by the explosive advance in the content of the material or sand, called the Sub-drilling blasting is not intended to make results happen toes or bumps on the floor of the mine that resulted in heavy equipment difficult to move when loading and transportation of blasting.
After condition by a series of explosives such as TNT or ANFO is equipped with nonel, we then filled covering material called stemming function withstand pressure up to the energy produced by the explosive spread of direction and control every aspect of destroying rock beside him.
In this case an important role is to control the firing process. in a blasting operation was preceded by drilling in the mining that aims to make the hole shot. Bullet hole itself will be filled by the explosive advance in the content of the material or sand, called the Sub-drilling blasting is not intended to make results happen toes or bumps on the floor of the mine that resulted in heavy equipment difficult to move when loading and transportation of blasting.
After condition by a series of explosives such as TNT or ANFO is equipped with nonel, we then filled covering material called stemming function withstand pressure up to the energy produced by the explosive spread of direction and control every aspect of destroying rock beside him.
Thing to consider in the process of blasting the rock properties are important:
- Violence: Prisoners of a smooth surface to abrasion.
- Violence is used to measure the technical properties of the rock material.
- Abrasiveness: Parameters that affect the wear (age) drill bit. Abrasiveness depending on the composition of rocks. Wear and tear on the drill bit is proportional to the composition of these rocks. The content of quartz in rocks is usually considered as a reliable guide to measure the wear of the drill bit (drill bit).
- Texture: grain structure of the rocks and can be classified based on the properties of porosity, density and grain size looseness. Texture also affects the speed of drilling.
- Structure: fractures, faults, schistosity and bedding areas of rock types, dip, strike.
- Breaking characteristic: describe the nature of the rock when hit with a hammer. Each rock type has a specific nature and degree of damage associated with the texture, mineral composition and structure
BLASTING EQUIPMENT
Blasting equipment is an auxiliary device is required to test and turn on a series of explosions so that the tool can be used repeatedly.
Blasting equipment can be grouped into:
1. Equipment directly related to blasting techniques
2. Support equipment blasting
The equipment is directly related to blasting;
* Triggers explosive tools
- In electric blasting (Blasting Machine)
- In nonel blasting (shot gun / short fire)
- Blasting Ohmmeter (BOM)
- Measuring electrical current leakage
- Blasting Multimeter
- Estimator blasting power machine
- Tracking lightning (lightning detector)
- Blasting Machine (DC electrical energy source), and ohm meters (series resistance testers), Rheostat (capacity of blasting machine tester)
- Cramper ( a type of special pliers for blasting and fire axes as clamp connection with ordinary detonators )
- Main wiring ( bus wire , leading wire) cable connecting the blasting machine (exploder) into an electric blasting circuit
Supporters blasting equipment include:
- The main support tools, dealing with aspects of safety and job security, as well as the environment, such as transport equipment and safety devices
- Additional support tools focused on blasting research that is not always used in the blasting routine, such as detonation velocity gauges, measuring gauges vibration and noise.
Blasting Supplies or Blasting Accesories are materials needed to make a series of blasting explosives so the entry can be turned on. Blasting equipment is used only once ignition only. Some blasting equipment that is:
Detonator
Detonator is a device that causes initial trigger initiation in the form of bursts (small explosion) as a form of action to give effect to the shock-sensitive explosive detonator or primer. There are two types of explosive charges in detonators, each distinct functions, namely:
- Primary charge form a powerful explosive that is sensitive (insensitive), its function is to receive the effects of heat very quickly and exploded, causing a shock wave
- Base charge is also called secondary field is a powerful explosive with a VoD high, its function is to receive the shock wave and exploded with a force magnitude depends on the weight of the base field
The types of detonators:
a. Electric detonators (electric blasting caps = EBC) there are two kinds of instantaneous detonators (instantenous EBC) and the detonator delay (delayed EBC)
b. Plain detonators (plain / ordinary detonators) are used with fire axes
c. Electronic detonators (connecting wire)
d. Insulator tape
Axis Blasting
The meaning here is blasting axis axis and the axis of explosive fire. Flame axis is the axis which are connected to a detonator in the normal detonation using ordinary detonators. It could be argued that the axis of the fire was a regular partner detonator, because ordinary detonators can not be used without a fuse. Flame axis function is to channel the fire with a steady speed on ordinary detonators. While the axis is the axis of the explosive core of PETN explosives there. Axis function is to assemble an explosive detonation system without the use of explosive detonators inside the hole. Axis has explosive properties are not sensitive to friction, impact, wild currents, and static electricity.
DESIGN OF EXPLOSION
Certain conditions on the operation will affect the design in detail rather than blasting. Factors considered in designing a detonation, among others:
1. Diameter hole explosive
2. high levels of
3. fragmentation
4. Burden and spacing
5. rock structure
6. The stability of the ladder
7. Impact on environment
8. Type of explosives to be used
1. Diameter hole explosive
2. high levels of
3. fragmentation
4. Burden and spacing
5. rock structure
6. The stability of the ladder
7. Impact on environment
8. Type of explosives to be used
Diameter of drill hole
Selection of explosive hole diameter is influenced by the size of the planned production rate. The larger the diameter of the hole you will get a greater production rate, with terms and conditions of rock drill tool same. Factors that limit the explosive hole diameter is:
- The size of the explosion fragmentation
- Filling the main explosives should be reduced or smaller than the technical calculations for the earth vibration or economic considerations
- Purposes of rock excavation is selectively
Where: d = Diameter of drill hole (mm)
High levels of K = (m)
With a small diameter drill hole, consequently burden too small, fragmentation will give good results with vibration ( groun vibration) is low. It is worth noting, especially when performed close to the housing boom population
Ladder heights and depths of drill holes
High levels closely related to other blasting parameters and geometry determined in advance or sometimes determined later after the parameters as well as other aspects in the know. High levels of max are usually influenced by the ability to drill and cup size (bucket) and the high range of tools and unloading. Commonly used on quarry or open pit mine with a large hole diameter is usually used between 10 - 15 m. Another consideration that must be considered is the stability of the ladder not to collapse, either because the carrying capacity is weak or vibration due to blasting. In practical relations borehole diameter with a height levels can be formulated as follows:
K = 0.1 to 0.5 D
Where: K = High level (m)
D = Diameter of hole (mm)
High levels closely related to other blasting parameters and geometry determined in advance or sometimes determined later after the parameters as well as other aspects in the know. High levels of max are usually influenced by the ability to drill and cup size (bucket) and the high range of tools and unloading. Commonly used on quarry or open pit mine with a large hole diameter is usually used between 10 - 15 m. Another consideration that must be considered is the stability of the ladder not to collapse, either because the carrying capacity is weak or vibration due to blasting. In practical relations borehole diameter with a height levels can be formulated as follows:
K = 0.1 to 0.5 D
Where: K = High level (m)
D = Diameter of hole (mm)
Fragmentation
Fragmentation is a general term to indicate the size of each chunk of rock blasting results. Fragmentation depends on the size of the next process. Some general rules about the relationship with the hole explosive fragmentation:
a) The size of the hole will result in explosive large chunks of fragmentation, then reduced by using more powerful explosives
b) The addition will add to toss explosive
c) rocks with high intensity and amount of explosives combined with a slightly shorter spacing will result in fragmentation of small
Fragmentation is a general term to indicate the size of each chunk of rock blasting results. Fragmentation depends on the size of the next process. Some general rules about the relationship with the hole explosive fragmentation:
a) The size of the hole will result in explosive large chunks of fragmentation, then reduced by using more powerful explosives
b) The addition will add to toss explosive
c) rocks with high intensity and amount of explosives combined with a slightly shorter spacing will result in fragmentation of small
GEOMETRY EXPLOSION
a. Burden
Burden is the most important dimension in determining the success of a blasting job. To determine the amount of burden to know the price of the burden ratio. Things that must be considered in determining the burden is:
· Burden must be a distance of charge (charges) perpendicular to the "free face" nearby, and the direction in which the transfer will occur
· The amount of burden depends on the characteristics of rocks, characteristics of explosives, and so forth.
Burden is the most important dimension in determining the success of a blasting job. To determine the amount of burden to know the price of the burden ratio. Things that must be considered in determining the burden is:
· Burden must be a distance of charge (charges) perpendicular to the "free face" nearby, and the direction in which the transfer will occur
· The amount of burden depends on the characteristics of rocks, characteristics of explosives, and so forth.
b. Spasing
Spasing is the distance between drill holes are arranged in one row (row) and measured parallel to the "pit wall". Spasing usually depends on the burden, the depth of drill holes, location of primary, time delay and direction of the field structure of rocks. For materials (rocks) are homogeneous B = S, while for complex rock structures, such as joint orientation parallel to the ladder then the burden can be sealed and spaces can be thinned to a spacing. When the joint orientation perpendicular ladder then the burden can be thinned to a spacing and spacing somewhat sealed. As for the structure with orientation control every aspect of the rock / rock fracture.
Spasing is the distance between drill holes are arranged in one row (row) and measured parallel to the "pit wall". Spasing usually depends on the burden, the depth of drill holes, location of primary, time delay and direction of the field structure of rocks. For materials (rocks) are homogeneous B = S, while for complex rock structures, such as joint orientation parallel to the ladder then the burden can be sealed and spaces can be thinned to a spacing. When the joint orientation perpendicular ladder then the burden can be thinned to a spacing and spacing somewhat sealed. As for the structure with orientation control every aspect of the rock / rock fracture.
c. Stemming (T)
Stemming also called the collar, this stemming largely determines the price of the stress balance in the drill hole, another function is to confine the gas that arise. To obtain the stress balance stemming price equal burden. In a compact rock, if the comparison between the stemming and the burden is less than one then it will happen cratering or break back, especially on the collar proming. Usually the standard price of pliers used is 0.70 and this is enough to control the blast of water balance and stress.
Stemming also called the collar, this stemming largely determines the price of the stress balance in the drill hole, another function is to confine the gas that arise. To obtain the stress balance stemming price equal burden. In a compact rock, if the comparison between the stemming and the burden is less than one then it will happen cratering or break back, especially on the collar proming. Usually the standard price of pliers used is 0.70 and this is enough to control the blast of water balance and stress.
c. Sub-drilling (SD)
Is part of the explosive column hole located at the base level is meant to avoid a toe on the floor level after blasting
d. High level (H)
e. Drill hole depth should not be smaller than the burden. This is to avoid going or cratering.
Is part of the explosive column hole located at the base level is meant to avoid a toe on the floor level after blasting
d. High level (H)
e. Drill hole depth should not be smaller than the burden. This is to avoid going or cratering.
H = L - SD
Where: L = depth of hole explosive
SD = sub drilling
Where: L = depth of hole explosive
SD = sub drilling
In general, the pattern shows the sequence of detonation or explosion of the number of holes sequential presence of explosive detonation sequence means that there is a lag time of explosion is called the delay time. Several advantages are obtained by applying the time delay in detonation systems are:
1. reduce vibration
2. Reduce over break and stone fly (fly rock)
3. Reducing the unrest caused by air blast and noise (noise)
4. Can direct the fragmentation of rock throwing
5. Can improve the results of explosive rock fragmentation size
1. reduce vibration
2. Reduce over break and stone fly (fly rock)
3. Reducing the unrest caused by air blast and noise (noise)
4. Can direct the fragmentation of rock throwing
5. Can improve the results of explosive rock fragmentation size
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