An inlet bench blasting operation was conducted at site DT-1 on January 11, 2010. Nitroglycerin explosives were used to blast 27 meters of rock. The blasting resulted in controlled fly rock within 20-25 meters and good fragmentation with a pull of nearly 4 feet. Some modifications were recommended, such as using the same delay sequence between connectors and for detached rock blocks.

1. Inlet bench blasting DT-1
RIGHT
ABURTMENT
Dam Axis
DT-1Blasting area

2. Inlet bench blasting DT-1
• Site – DT-1
• Date – 01/11/10
• Time – 01:30PM
• NED consumed:-1/20, 2/20, 3/20,
6 Mtrs
AREA OF DT-1
27Mtrs
• NED consumed:-1/20, 2/20, 3/20,
5/25, 6/20, 7/20, 8/15,
9/10, 10/20, 16/30.
• MS Connector used: 17ms/5, 25ms/5
• ED used: 3/2
• Detonating fuse- 100mtrs
• Explosive consumed: 45 Kg
10.5 Mtrs
5 Mtrs
27Mtrs

3. Explosive per Hole
• Catridge Size:(25X200)mm
• Weight per catridge: 125gm
• Charging: 1 to 3 catridges per hole.
1 catridge /hole in river side row.
3 catridge/hole in hill side row.
2 catridge /hole in other mid rows.
2.9Feet1.1Feet
DrilledHole
HoleLength5Feet
Stemming material
Explosive

4. OBSERVATION
• Here the row alignment was not
done parallel to river side free
face, due to reduce the fly rock.
• Surface was covered with
small broken rock fragments,
which may possiblewhich may possible
for fly rock.
• For precaution surface
should be clean before
blasting.
Delay No-10
TeestaRiver
HillSlopeSide

5. RESULT
• Blast taken at :-17:20 IST
• Fly rock was controlled with radius up to 20 to
25 meters, which was nearly safe.
• The fragmentation was also good and pull was• The fragmentation was also good and pull was
nearly 4 feet.
• This firing pattern should continue till the
same rock type will continue.

6. SOME MODIFICATIONS
• There should be same delay sequence in between the MS-
connectors.
• Same delay should be used for detached rock block present in the
bench.
Initiation
Initiation
Delay 1Delay 1
Delay 2Delay 2
Delay 3Delay 4 Delay 3
Delay 4Delay 4 Delay 3MS Connector
Delay 1Delay 1Delay 1Delay 1
Delay 2Delay 2Delay 2
Delay 3Delay 3Delay 3
Initiation
MS Connector
Hole D Cord
MS Connector
MS Connector
Hole D Cord

7. About Author
M. K. PandaM. K. PandaM. K. PandaM. K. Panda
Senior Research FellowSenior Research FellowSenior Research FellowSenior Research FellowSenior Research FellowSenior Research FellowSenior Research FellowSenior Research Fellow
CSIRCSIRCSIRCSIR----CIMFRCIMFRCIMFRCIMFR
DhanbadDhanbadDhanbadDhanbad
Email:Email:Email:Email: panda.malay4@gmail.companda.malay4@gmail.companda.malay4@gmail.companda.malay4@gmail.com
Other Publications:Other Publications:Other Publications:Other Publications:
http://www.sciencedirect.com/science/article/pii/S001379521http://www.sciencedirect.com/science/article/pii/S001379521http://www.sciencedirect.com/science/article/pii/S001379521http://www.sciencedirect.com/science/article/pii/S001379521
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