Blast-free Mining
Abhinay Hatewar elaborates on a new technology introduced to replace rock blasting in mining.
Rock blasting is the controlled use of explosives to excavate, break down or remove rock. It is practised most often in mining, quarrying and civil engineering such as dam or road construction. Except in mining, the result of rock blasting is often known as a rock cut.
Blasting methods can cause damage to environment, habitation, safety of workers and also quality of product due to mixing of overburden (OB) and excavated rock. There are various issues and hazards associated with blasting.
Environmental issues: The rock blasting leads to a number of impacts on the environment. Open cast mining near the residential areas has become inevitable and therefore environmental impacts are required to be mitigated. Ground vibrations, noise and fly rock are the important environmental impacts as they may damage the properties. A proper blast design ensures effective utilisation of the energy of the explosives and is therefore the answer to the problem of mitigation of the environmental impacts.
Safety issues: Blasting near habitat, roads or establishment is out of the safety bond. Danger of fatality by fly rock is prominent.
Selective mining: Loss of precious raw material mixed/ sandwiched in ore body. Due to excess use of explosive mixing of ore body with gangue can take place causing increase in time and work load for the excavation.
Explosive loss/safety: Handling the explosives is a dangerous and responsible job. Loss of explosives can be used for destructive forces. Also, if the rock is fractured, energy loss is obvious. The amount of explosives to be used can be controlled but destruction can be out of human limitations.
Secondary blasting: When the rock is fractured or loosely compacted, there is formation of boulders. These boulders are blasted to break, in which damage by fly rock is possible. Fly rocks are considered to be the most undesirable movement of rocks during the blasting activities. Damage by a fly rock cannot be refuted; the evidence is usually present and visible. Fly rocks can be a result of overcharge, too small burden, or basic loose rocks on the crest of the bench.
Considering the above-mentioned primary issues regarding blast mining, some alternative is needed. To fulfill the need, mines are expanding, simultaneously people are becoming aware of exploitation of natural recourses; which may cause frequent stoppage of mining/excavation. Also companies are putting strict control over usage of explosives. All these situations are making the blast mining slow and low on production. So for the blast-free mining, some machinery is used for progressive and sustainable development and for continuation in production.
Terminator impact hammer
This is the ideal solution for extraction/primary breaking in a variety of rock formations without drilling/blasting. Terminator hammers are arguably the world?s most powerful rock extraction tools.
Operation principle: The hammer works on drop-ball method. The dead weight inside the frame is lifted up with the help of hydraulic power employed from hydraulic excavator. The lifted weight is allowed to fall freely with gravitation. This weight when falls at striker pin, it generates impact energy. This impact energy is used to drive striker pin into the rock mass. With every hit, the pin progresses into rock mass breaking it apart. Terminator?s incredible impact power of 90,000-182,000 Joules (equals to 18~22 g of explosives) can be used in extraction of the most compact and the toughest rock mass. During this process, hydraulic excavator is used to provide hydraulic energy, to hold and operate terminator and to extract rocks when dislodged from the mass.
Extraction process: Terminator hammers break and extract rocks/compact material by shock, not vibration. With every impact, the pin (chisel) develops micro-cracking into the rock mass, compact mass and concrete, shattering the material by about 2 cu m around and beneath the impact penetration area of the point. The pin entering by about 1.5 m shall completely shatter and crack. Further progression of this on rock mass make easier to extract. One hit for DX1800 is equivalent to about 18~22 g of plastic explosive.
Product range and specifications: Currently two models, with the energy levels varying from 90,000-182,000 Joules are manufactured.
The author is Director - Business Development, Houtec Engineering & Services Pvt Ltd.
Rock blasting is the controlled use of explosives to excavate, break down or remove rock. It is practised most often in mining, quarrying and civil engineering such as dam or road construction. Except in mining, the result of rock blasting is often known as a rock cut.
Blasting methods can cause damage to environment, habitation, safety of workers and also quality of product due to mixing of overburden (OB) and excavated rock. There are various issues and hazards associated with blasting.
Environmental issues: The rock blasting leads to a number of impacts on the environment. Open cast mining near the residential areas has become inevitable and therefore environmental impacts are required to be mitigated. Ground vibrations, noise and fly rock are the important environmental impacts as they may damage the properties. A proper blast design ensures effective utilisation of the energy of the explosives and is therefore the answer to the problem of mitigation of the environmental impacts.
Safety issues: Blasting near habitat, roads or establishment is out of the safety bond. Danger of fatality by fly rock is prominent.
Selective mining: Loss of precious raw material mixed/ sandwiched in ore body. Due to excess use of explosive mixing of ore body with gangue can take place causing increase in time and work load for the excavation.
Explosive loss/safety: Handling the explosives is a dangerous and responsible job. Loss of explosives can be used for destructive forces. Also, if the rock is fractured, energy loss is obvious. The amount of explosives to be used can be controlled but destruction can be out of human limitations.
Secondary blasting: When the rock is fractured or loosely compacted, there is formation of boulders. These boulders are blasted to break, in which damage by fly rock is possible. Fly rocks are considered to be the most undesirable movement of rocks during the blasting activities. Damage by a fly rock cannot be refuted; the evidence is usually present and visible. Fly rocks can be a result of overcharge, too small burden, or basic loose rocks on the crest of the bench.
Considering the above-mentioned primary issues regarding blast mining, some alternative is needed. To fulfill the need, mines are expanding, simultaneously people are becoming aware of exploitation of natural recourses; which may cause frequent stoppage of mining/excavation. Also companies are putting strict control over usage of explosives. All these situations are making the blast mining slow and low on production. So for the blast-free mining, some machinery is used for progressive and sustainable development and for continuation in production.
Terminator impact hammer
This is the ideal solution for extraction/primary breaking in a variety of rock formations without drilling/blasting. Terminator hammers are arguably the world?s most powerful rock extraction tools.
Operation principle: The hammer works on drop-ball method. The dead weight inside the frame is lifted up with the help of hydraulic power employed from hydraulic excavator. The lifted weight is allowed to fall freely with gravitation. This weight when falls at striker pin, it generates impact energy. This impact energy is used to drive striker pin into the rock mass. With every hit, the pin progresses into rock mass breaking it apart. Terminator?s incredible impact power of 90,000-182,000 Joules (equals to 18~22 g of explosives) can be used in extraction of the most compact and the toughest rock mass. During this process, hydraulic excavator is used to provide hydraulic energy, to hold and operate terminator and to extract rocks when dislodged from the mass.
Extraction process: Terminator hammers break and extract rocks/compact material by shock, not vibration. With every impact, the pin (chisel) develops micro-cracking into the rock mass, compact mass and concrete, shattering the material by about 2 cu m around and beneath the impact penetration area of the point. The pin entering by about 1.5 m shall completely shatter and crack. Further progression of this on rock mass make easier to extract. One hit for DX1800 is equivalent to about 18~22 g of plastic explosive.
Product range and specifications: Currently two models, with the energy levels varying from 90,000-182,000 Joules are manufactured.
The author is Director - Business Development, Houtec Engineering & Services Pvt Ltd.
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