Introduction to Blasting Technology

Welcome to the first lecture of the Drilling and Blasting Technology.

In last class, we have discussed about the drilling and the introduction to drilling

is already discussed to you. You have understood the overview of drilling what is the present status in the world, what

is the history of drilling in the drilling in the world as well as the national status

also. You have understood the learning objective why you should read drilling part and what

is the objective of this course; and if you carry on this course what you can do in your

professional life related to drilling. So, that was the retrospect of the last class.

And last class we have also mentioned properly that this drilling technology is limited to

the drilling in the rock for excavation purpose this is the drilling in the rock for excavation

purpose. Other drilling requirements though it was shown in the last class, but it is not the

within the per few of this course. So, this drilling is for the rock excavation and the drilling is carried out only to place

the explosive inside the rock so that the explosive can be exploded for rock excavation.

So, basically that is why this course is drilling and blasting and now let us see; the overview

of explosive. So, you can see the moment we talk about explosive you understand that something has to be exploded.

So, in this video you can see we are exploding a Military ammunition, then we are exploding

a building intentionally this building is being exploded because it is damaged it has

to be exploded it has to be demolished. Similarly, you can see in this video we are going for the excavation of the rocks for

civil construction purpose. You see this rock is being excavated so that a newly road can be constructed in the Hilly

terrain. So, this rock excavation is carrying out for civil construction purpose.

So, this you can see this is a mining case where the excavation is being carried out

for the mining purpose. And this is a very good video you must observed this with a little bit patience.

And I must tell that this is one of the very very good quality of blast.

If anyone ever ask you can see and you can tell them that this is a very very good quality

blasts carried out in this case. You can see so many explosive is being blasted, so many explosive is being blasted and the

rocks are being fragmented. So, what is happened here, the drills are creating the holes in that hole explosives

are given and the explosive when it is exploded the rocks are fragmented.

And such a beautiful fragmented rock you can see the moment this gas will be goes out. You will find out how the explosion occurred and how the rocks are moving this is in a

not in a real time this is a slow pace time. This is showing in a very very slower mode and how fantastic fragmentation occurred.

So, that is why I told earlier this is a very very good quality blasting.

This is the explosive explosion in the underground case.

You can see the holes are there and it is now initiated the connections are being blasted

now, and after this blasting of this connection you will find out the rock will be broken

by the explosion of the explosive.

So, you understand that explosive is a chemical if it comes in the contact with the flame

or something stimuli then it explodes. And we commonly know this we know the explosive also which comes into the contact of heat

or flame and exploded. And what is happened when we intended to do this when we want the there must be some explosion

created by the explosive that is called blasting. If it is accidently occurs that means, if the chemical is exploded but not as at our

intention, but accidently that is called explosion. So, often you have heard that is may be some oil tanker is going on the street and it is

exploded because, of some stimuli or some fire comes into the contact of the oil it

is exploded that is unintentional that is why it is called explosion. If intentionally it is being done then this is called blasting.

So, basically, explosive the moment we utter this term we find that this is this causes

the people they are very very sensitive by hearing this term explosive.

The reason is explosive is a small chemical and huge quantity of energy is stored in this.

And the most problematic is the moment this energy is released it is released almost instantaneously.

So, these instantaneous release of the energy from a small source make it so dangers, that

is why people are afraid of this. People do not like to touch it, do not like to come in close to this and the moment some

explosive is recovered from some place the total area has been asked vacated.

So, because of this enormous storage of energy explosive is so many, so dangers.

So, that is why this explosive handling is very careful and explosive must be taken care

by the authorized person who knows the details of the explosive.

In fact, this course is such so that after going through this course a person should

be considered about the expert in explosive and blasting, and he can be considered as

a competent person who can handle explosive for any case.

It may be during the rock excavation case, it may be during the handling of explosive case, it may be during the manufacturing of the explosive case.

So, that is why attending this lectures in this course is very important to know the

details of the explosive and blasting of this.

So, let us see the history of the explosive first.

What was happened in the ancient china first explosive was discovered and no one knows

who has discovered it, but the explosive still which we are using in our crackers etc., that

explosive was developed in the ancient china and they develop that for their amusements.

And that is the first discovery of explosive and that was the only explosive since the

middle age, later on those formula were stolen by the European people. And then, those formula were used in the Europe for a long time and the further development

related to explosive were occurred in the Europe, USA, Australia etc.

And this explosive history is very interesting and you will find out most of the time the

new explosives are developed from some accidents. So, explosive basically a chemical which is storing huge quantity of energy, people are

afraid of that and it is essential that we should know how this energy should be released

from that small chemical and how that can be in the controlled manner will be utilized

for as far our intention. Basically a rock excavation is also one type of that.

We utilize this huge energy for some good of the civilization where we break the rock

for the development of the civilization. But as you have seen the video there we have found the first video was shown to you that

one navy ship was releasing one missile which is carrying the explosive.

So, this is basically the use of explosive for the war or terrorism.

And see this is very very unwanted use of the explosive, probably the scientist who

discovers those explosive never thought of this type of utilization but anyway this is

not within our hand. But we classify this type of use of explosive as the military blasting so that this is completely

unwanted for us. We are morely interested in the use of explosive for the blasting of our commercial requirement,

one requirement is the building demolition; one building demolition video is already shown

to you. This photograph I am showing to you where n number of chimneys are there which are being

blasted for demolishing so that the economically the structure will be demolished.

And another requirement is the excavation of the rock material some of the excavation

of the rock material videos are shown to you this is one similar type of use of explosive.

And this type of use of explosives are called commercial explosive.

But this is not the limitation of the use of the explosive, apart from this there are

other use of explosive. Say one very good use of explosive is being carried out by the geological exploration

people where they explore the explosive inside the earth crust to generate the seismic waves

which they utilize for their seismic exploration of the earth crust.

In fact, say oil are being explored of that type of cases, exploding some explosive inside

the earth crust seismic waves generates the reflected seismic waves are measured and the

resources of the oils are identified like that way. So, there are n number of such type of utilization of the explosives are there which are commercial

use, but not for the military purpose not for the excavation purpose, but for other

purposes we are using.

This present course is limited to the commercial blasting of the rock excavation only and the

objective of this blast is to fragment the rockmass in a desirable size distribution.

This is very very important. This is not that we are fragmenting the rock mass in some few number of very large species

and few number or huge quantity of dashes that is totally unwanted, we want that the

fragment size should be there that means, the rock mass will be fragmented in such a

manner different size of fragment should be generated. So, this generation of different size of fragmented rock is called fragment size distribution.

So, we want the explosive should be used in such a way, so that the rock mass will be

fragmented and fragmented to a desirable fragment size distribution.

So, that is the main objective of use of explosive for the rock excavation.

There are other purposes also of using explosive in the rock excavation, but the primary purpose

is that we want to fragment the rock to our desirable size distribution.

So, this is our essential requirement that we must use explosive, place those explosive

in our drill holes such manner so that the explosives explode, the explosive energy will

be utilized for fragmenting the rock.

We want to throw the rock also. So, that it is fragmented and it is dislodged or moved a little bit but we do not want that

it should move a lot. We want that fragmented rock should move a little bit so that some loading machine, some

gathering machine should come and take out the next processing or next handling of the

fragmented rock. So, this throw of fragmented rock is wanted and it is wanted judiciously and if you look

into the present day scenario. In India only for rock fragmentation purpose we are using few million tons of explosive

every year. So, let me give you some account of rock excavation what we are carrying out in India, not the

world scenario, in Indian scenario. In Indian scenario we are excavating more than 2 billion tons of material that means

2000 million tons of material we are excavating every year from more than 4000 mines.

And we are utilizing few million tons of explosive for excavating those rocks, this is for the

mining purpose only. Apart from that huge quantity of explosives are also required for the civil excavation

purpose, in the tunnels, in the road ways, in the trenches in the metros all those places

we need to excavate the rock using the explosives only.

But there are some problems of using explosive as a source of energy for the excavation purpose.

The first problem is that explosive is chemical source of energy, we utilize that in blasting

for releasing the energy utilize that for fragmenting the rock. But what is happened this release of energy from chemical to the mechanical shock energy

or to the heat energy which is being carried out in the explosive is very very uncontrolled.

That means, the release of energy from explosive is very very uncontrolled and that is why

a knowledgeous person, a technically competent person is essentially required to design these

explosions. Unless and until this explosion are designed to be termed as blasting these explosions

can go to anyway, it may lead to a positive way or to the negative way.

So, that is why we do not want that should be any injury, we do not want there should be any fatalities while the blast is being carried out, while the explosive is being

handled. And that is why this course is very very important for generate the competent man power, to generate

the competent man power in the field of drilling and blasting technology.

So, rock is fragmented by blasting utilizing the shock energy, releases from the explosive

and; remember this release of energy is instantaneously.

If you look into the intension of the releasing of energy from explosive, it is almost less

than a millisecond. So, that is why this release of energy can be considered as the instantaneous release

of energy and this is very very high. Often the pressure which is generated by this release of energy exceeds 2,50,000 bar, so

that means, this is very very high this is more than 250 kilo bar pressures are generated

by the explosions which if something comes in front of that explosion it will devastate

that one. And this biggest problem of uncontrolled energy release demands very very careful and judicial

handling of the explosive. Therefore, it is very strongly recommended that a person must go through the basic courses

of drilling and blasting prior to be considered as a competent person as the blaster or as

a blasting technologist who can give 100 percent safety during the use of the blasting.

In fact, use of explosive or handling of explosive by in competent persons are strictly banned

as per the law of the country. Nowhere throughout the world, it is allowed to handle hold, use of explosive by any incompetent

person. So, this course is designed to achieve the objectives, first again as we are using explosive

to fragment the rock here the rock is the medium. So, first we need to understand the rock as a blasting medium which would be fragmented

properly, so that means, we have to place the explosive inside the rock.

How it will be placed? It should be distributed inside the rock mass.

How it will be distributed? It will be specially distributed that means, it will be distributed in space.

If you think imaginary that to achieve the best fragmentation what we want?

That, we want that every small cube of rock should have a very small element of explosive,

so that it can be fragmented properly and that explosive must be placed at the center

point of the block. But practically this is not possible we have to drill as per our desired drilling pattern.

So, that we can distribute the explosive spatially inside the rock mass and this spatial distribution

this spatial distribution will give us good distribution which can give us the better

fragmentation which can give us the desired fragmentation of the rock mass on exploration

of this explosive. We want this course one of the objective of this course again that the student should

understand the different explosives and the accessories.

Say explosive is the requirement is the storage of energy which is the requirement to release

the energy for the blasting but explosive need some accessories also.

These accessories are essentially required to provide the safety of the people who are

handling these. Not only that this will also provide the tool to the user where he will control the release

of energy from one position to another position; That means, this accessory is the tool these

accessories are the tools for the blast designer blast engineer where he will control the release

of the energy inside the rock mass apart from that he is achieving his own safety using

these accessories. So, these accessories are very very important in the explosive and its use in the commercial

blasting. Blasting always associated with some special terminologies say I am giving one example

say burden. Burden means if you are coming to the literally term burden, burden means something which

is dumped on to you are unable to withstand the load of that that is called burden you

may tells us that is giving more burden to us more that means, I am giving more task to you.

So, this burden, but if you are using a burden term in the blasting then the burden term

is different, because here burden is the, a specified length of rock mass which is intent

to be blasted by one group of explosive. So that means, the terminology is little bit different in the blasting and a blasting technologist

a blasting engineer must know the use of this terminologies. So, one objective is to understand these terminologies.

Then next which is very very important and personally I believe without this knowledge,

an explosive engineer should not be considered as an explosive engineer that is the understanding

of the explosive rock interaction. That means, the moment explosive is generating the seismic waves, explosive is generating

the mechanical wave, how that mechanical wave is interacting with the rock, how that is

propagating, how that is fragmenting the rock mass, how the fragmented rockmass are dispersed

from the place or moved from the place. If explosive engineers are unable to understand this then they cannot be considered as the

competent person. So, this is very very important objective of this course, I want each and every student

must understand the explosive and rock interaction. And this explosive rock interaction will lead you to the understanding of the theory of

rock blasting, how the rocks are being blasted in different conditions, different spatial

distributions, how the rocks will be blasted that is the theory of the rock blasting.

This is one of the main objective of this course.

This based on this blast theory one has to know the blast design criteria.

Then if the matter is like this a blasting engineer should be given task a blasting is

engineer should be given task that you have to address you have to address this solution

that means, you have to address this fragment size distribution with this quantity of throw

and with limitation or with the constant of these are the other environmental parameters.

So, this is the constraints which you need to address this is the target which you need

to address and for that you have to design a blast. So, understanding of the blast design criteria is very very important.

The next point is to design a blast round considering the criteria, one person has to

design the blast round. Again it is for surfaces excavation that means, the second one is underground excavation that

means, whatever is the excavation whether it is in the surface or it is in the underground

the laid down target is there desired fragment size distribution, desired control breaking,

desired throw. All these targets are there. Constraints are there fume characteristics constraints are there, vibration constraints

are there, throw of the rock, fly rocks etc. all those constants are there one has to address

those constant, one has to address those target and considering that he has to design the

blast. Apart from that specific requirement one has to understand which leads to the, which is

required in the blasting in the explosive environment. That means, if you are considering the case of the underground coal mines where because

of the occurrence of the methane etcetera it is the environment itself is the explosive

environment still the blasting has to be carried out for excavating the rock. So, the special requirements are there and the blasting engineers should understand those

requirements. Then the next objective is to measure and calculate the performance of a blast.

I strongly believe if the performance is not measured, performance is not calculated then

the technology cannot be approved, their technology cannot be accepted. So, the moment a blasting engineer is designing some blast he must able to measure or calculate

the performance of this, he must able to calculate the financial appraisal of the blast.

So, that whether that blast is economically acceptable or not that can be addressed.

And not only the end of that performance, but also essential it is required that the

student must able to understand and assess the environmental impact of the blasting.

So, that is very very important the blasting should not create any nuisance to the environment.

There are some special blasting methods required that has to be one of the objectives student

should learn. And the last, but very very important the safety precaution requirement in the blasting,

and in the explosive handling; This is essentially required because the explosive is the huge

source of energy and that immature release of that may lead to any type of fatality.

So, what is the expectation? My expectation that if a student is appearing in this course studying it well he must able

to design a blast round for rock excavation, irrespective of the geo mining condition.

It may be strong rock, it may be weak rock, it may be in the underground case, it may

be the surface case, it may be a surface case where the inhabitance are very close we do

not want that rock should fly to his house. It may be the surface case where some sensitive structure is there historical structure is

there. It may be the case where explosive environment is there like underground coal mines, but

we need to blast it. So, in this all type of cases rock has to be excavate because it is the need of the

civilization and our student must address by designing those rock excavation by blasting

after going through this course. I must want that a student also should evaluate the performance of the blast what he has designed.

He has designed a blast if is enable to evaluate its performance, evaluate its economics, evaluate

its safety precautions then it is very difficult. So, that is why the students should know how to evaluate the performance and they must

evaluate the performance in economic term, in safety term in environmental term.

They must estimate or evaluate the environmental impact of the blasting; they must evaluate

the economics of the blasting. They must know how to optimize the performance of a blast in case of surface and underground

mines. Say this is very very very important part say always having the highest profit may not

give you the optimized one say highest profit may be may be achieved in the blasting unit

operation only but that may lead to loss in other unit operations So, optimization is very very important where all the unit operations will be considered

and the overall costing will be minimized. So, optimized performance by a blast design for both surface and underground excavation

is very very important and I want my student must know how to do this one.

And this must lead to two SOP (standard operating procedure), our student who are attending

this course should able to design the standard operating procedure for the rock blasting.

Because everyone in the vicinity of the blasting area everyone associated with the blasting

practices should know this standard operating procedure, because there may be a small mistake

by a person that may lead to the fatality of 20-30 people. So, that is totally unwanted we do not want any ignorance should go for that one that

is why standard operating procedure must be developed and must be followed for every blasting

practice. And not only in the blasting practice, but also it is essentially required for the explosive

handling. That means, the moment you are releasing you are issuing the explosive from the magazine

from that moment till the explosives are being used in the mines for the blasting.

And the excess explosives are return back to the magazine again for their storing purpose

till then the magazine, the explosive everything has to be handled with the standard operating

procedure. There should not be any deviation allowed in the standard operating procedure, and I

want the people who are attending this course should know how to design this sops.

Now, let us consider the textbook and reference books.

So, these are the books students must follow during this course.

These books are very good; these books are available in the internet, available in the most of the libraries.

There are some reference books also which are available very commonly available to the

libraries and the internet resources. Apart from this lectures videos that could be helpful for the students for their using

this in this course. Thank you.