Blasting-Circulars-PPT Blasting-Circulars-PPT.pdf

Blasting

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2. BLASTING REGULATIONS OF MMR
1961 & DGMS CIRCULARS ON THEM

3. MMR 153
Type of Explosives to be used in mines
No explosive shall be used in a mine except
that provided by the owner, agent or manager.
Shall be of good quality & good condition

4. CIRCULARS ON MMR 153
Circular 2 of 1947
Only dry gunpowder should be issued
Circular 4 of 1980
Danger associated with use of ANFO in pyrite
bearing ores- At elevated temperatures, AN-FO
reacts exothermally with pyrite and the reaction
becomes self-sustained at 120 ± 10°C. you may
take appropriate action.
Circular 5 of 1985
Quality and condition of explosives provided for use
in mines
Circular1 of 1981
Storage of explosives beyond its shelf life

5. MMR 154
Storage of explosives
No owner / agent / manager shall store or allow to
store any explosive within the premises of a mine .
Explosives shall not be taken into or kept in any
building except a magazine duly approved by the
License Authority under the IE Act, 1884
Every license or a true copy thereof, shall be kept
at the office of the mine.


Circulars On MMR 154
Circular 65 of 1965
Temporary storage of explosives near the entrance of
a mine

6. MMR-155
Cartridges
No explosive, other than a fuse or a detonator, shall
be issued for use in mine, or taken into or used in
any part of a mine, unless it is in the form of a
cartridge. Cartridges shall be used only in the form
in which they are received.
The preparation of cartridges from loose
gunpowder, the drying of gunpowder an the
reconstruction of damp cartridges shall be carried
out by a competent person and only in a place
approved by the Licensing Authority

7. MMR 156
Magazines, stores and premises to
store explosives

Every magazine, or store or premises, shall be in charge
of a competent person.
Explosives shall not be issued unless they are required
for immediate use. If any explosives are returned, they
shall be reissue before fresh stock is used.
Explosives shall be issued only to competent persons
upon written requisition signed by the blaster or by a
official authorized and only against their signature or
thumb impression. Such requisition shall be preserved
by In-charge of the magazine or store or premises.
The person in charge of the magazine or store or
premises shall maintain, record of explosives issued to
each competent person and a similar record of
explosives returned to the magazine or store or
premises.

8. 1. Pilferage of explosive MMR 156
Circular 2 , 1940 & 4 , 1949
Employment of trustworthy persons & checks

1. Only such persons should be appointed as
magazine in charges, Blasters and explosive carriers,
who have been found to be entirely trustworthy.
2. The number of Blasters and explosive carriers
should be kept to a minimum.
3. Managers should frequently have surprise
checks on the amount of Explosives.

9. 3. Pilferage of explosive MMR156
Circular 13 , 1956 & 9, 1957
Pilferage of explosives through authorized
persons

Managements are requested to furnish DGMS with a list of
the Blasters in service at their respective mines on 1st
January every year with the following details:
1. Name in full
2. Father’s name
3. Residential address
4. Home address
5. Number and kind of certificate he holds for firing shots.
A copy of the list should be sent to the Superintendent of
Police having jurisdiction in the area in which the mine is
situated.

10. 3. Pilferage of explosive MMR 156
Circular 44 , 1963
The quantity of explosives actually used by the Blasters
should be checked by a senior officer of the rank of an
Assistant Manager. The magazine in charge should be
asked to maintain a proper account of the quantity of
explosives issued from the magazine and the number of
shots fired.

11. 4. Pilferage of explosive MMR 156
Circular 33, 1964


A scheme for prevention of pilferage of explosives
Explosives are not handled by undesirable persons.
Cases & Containers – The lid of the box shall be Self locking ,
All boxes shall be colored & numbered.
Explosive Issue and Return Voucher shall be used.
Check in the Magazine - Explosive and detonators shall be
counted by the Magazine Clerk and entered in the transit slip
put the slip inside the box, close the box and hand over to
Blaster.
Return of unused Explosive to Magazine – The blaster shall
return the boxes to the magazine, and deposit key of the box
with the magazine clerk.
Conti…….

12. 4. Pilferage of explosive MMR 156
Circular 33, 1964

Final Checks - The manager or an assistant manager or
any other competent person specially authorized by the
manager for the purpose shall countersign every Transit
Slip
Stock Checking in the Magazine - The manager or an
assistant in every week.
Any overwriting of entries in the Transit Slip shall be
countersigned by the person making the same.
All the statutory explosive record books including the
book maintained under Reg. 169(b) & Regulation 156(4) of
the MMR shall be checked by the manager or an assistant
manager.

13. 5. Pilferage of explosive MMR 156
Circular 3, 1992

All explosive magazines in the mine area should be well
illuminated and well guarded.
Strict check should be kept on mining foreman and
blasters in mines to ensure that there is no pilferage of
explosives.
The proper maintenance of records pertaining to stock,
issue and return, use etc. of explosives should be strictly
monitored regularly by the manager and counter
checked by officer senior to manager

14. MMR 157
Cases and containers for carrying
explosives.
No explosive shall be issued except in a case or container of
substantial construction and securely locked. Cases or
containers made of iron or steel shall be heavily galvanized;
and no case or container provided for carrying detonators
shall be constructed of metal or other conductive material.
No detonator shall be kept in a case of container which
contains other explosives and 2 or more types of detonators
shall not be kept in the same case of container.
No case or container shall contain more than 5 kg and no
person shall have in his possession at one time in any place
more than one such case. Provided that the C.I. may permit
the carrying of a larger quantity in one case.
Every case or container shall be numbered; the same case or
container shall be issue to the same blaster. The key of every
case or container shall be retained by the blaster in his shift.

15. MMR 158
Transport of explosives
For U/G Mine
Precautions against
lowering / raising explosive
and carrying of explosives
on ladders

MMR 159
Reserve Stations
For U/G mine
No case container containing explosives shall be
left or kept below ground

16. MMR 160
Blasters
The preparation of
charges , charging &
stemming of holes shall be carried out by Blaster.
Blaster should have Manager’s, Foreman’s Mate’s
or Blaster’s certificate.
If 30 or more persons under the charge of a
competent person such person shall not perform
the duties of a blaster.
No person whose wages depend on the amount
of mineral, rock or debris obtained by firing shots,
shall be appointed to perform the duties of a
blaster
Conti….

17. MMR 160
Blasters
The manger shall fix the maximum number of
shots that a blaster may fire in any one shift and
such number shall not exceed 80 in case they are
fired electrically or an igniter cord and 50 in
other cases, and shall be based upon-The time
require to prepare , fire a shot and move between
places where shots are fired. Any other duty
assign to him and assistant.
Provided that the Regional Inspector may, by an
order in writing he may specify, permit the
manager to fix the maximum number of shots to
be fired by a blaster differently from the limits

18. MMR 161
Shot firing tools
Every blaster on duty shall be provided with
1.A suitable electric lamp or torch
2.A tool, made entirely of wood, suitable for
charging and stemming shot holes
3.A scraper made of brass or wood suitable
for cleaning out shot holes
4.A knife for cutting off fuses & a pair of
suitable crimpers for crimping detonators
No tool or appliance other than that
provided as above shall be used by a blaster.

19. MMR 162
Drilling, charging, stemming and firing of shot holes
A clearance of at least 0.3 cm over the diameter of the
cartridge of explosive & Hole
No detonator shall be inserted into a priming cartridge until
immediately used. Detonators once inserted into a priming
cartridge shall not be taken out.
The charge in any shot hole shall consist of one or more
complete cartridges of the same diameter and the same type
of explosive.
The blaster shall ensure that no charge in a shot hole is over-
charged of under-charged.
No shot hole shall be fired by a fuse less than 1.2 m in
length.
Every shot hole shall be stemmed with suitable non-
inflammable stemming. Only sand or soft clay lightly pressed
but not hard mixture of sand and clay or water shall be used
as stemming.
Conti…..

20. MMR 162
Drilling, charging, stemming and firing of shot holes
In charging or stemming , no metallic tool, scraper or
rod shall be used and no explosive shall be forcibly
pressed into a hole.
A shot shall be fired by the same blaster who charged
it.
In any mine in which explosives other than gun
powder are used, every shot shall, if so required by
the Regional Inspector, be fired electrically.
No more than 10 holes shall be fired in one round
unless they are fired electrically or by means of an
igniter cord.
No person shall remove any stemming otherwise
than by means of water or an approved device.
Where a large number of shots has to be fired, a shot
firing shall be carried out between shifts.

21. MMR 162
Circular 49 of 1959
Drilling, charging, stemming and firing of shot holes

Stemming material
The stemming material should be compact but
not hard. The use of mixture containing 70%
fine sand, 30% clay and a small percentage of
calcium chloride to keep it in a plastic condition
is recommended for the purpose

22. MMR 162
Circular 45 of 1963
Drilling, charging, stemming and firing of shot holes


Length of fuse outside the cartridge in fuse
firing
For the sake of safety of persons engaged on the
dangerous occupation of handling explosives, it is
necessary that not less than 1.2 m of fuse is kept
outside a cartridge.

23. MMR 162
Circular 01 of 1975
Drilling, charging, stemming and firing of shot holes


Forcing down of explosive cartridges
It is required that at no stage should attempts
be made to push any cartridge down when it
gets stuck up either because of insufficient
diameter, obstruction in the shot-hole or any
other reason.

24. MMR 162
Circular 05 of 1999
Drilling, charging, stemming and firing of shot holes

Charging and firing of explosives in a
crack, i.e. in an improperly drilled,
charged and stemmed shot hole

25. MMR 163
Electric Shot firing
Shot shall be fired by a suitable shot firing apparatus. The no. of
shots fired at any one time by the apparatus shall not exceed the
number for which it is designed.
Every electrical shot firing apparatus
1.Operated by a removable handle or plug, Handle or plug shall not
be placed in position until a shot is about to be fired and shall be
removed as soon as a shot has been fired.
2.No apparatus shall be used which is defective and every apparatus
shall once at least in every 3 months, be cleaned an thoroughly
overhauled by a competent person.
3.If the apparatus fails to fire, the blaster shall return the apparatus
to the manger or AM and it shall not be use again unless it has
been tested and found to be in safe working order
4.The result of every overhaul test or repair shall be recorded in a
bound paged book kept signed and dated by the person making
the overhaul, test or repair. Conti……

26. MMR 163
Electric Shot firing
No current from a signaling, lighting or power circuit shall be
used for firing shots.
The blaster shall
1.Retain the key of the firing apparatus in his possession
throughout his shift.
2.Use a well- insulated cable of not less than 20 m in length.
3.Before coupling the cable to the firing apparatus, couple up
the cable himself to the detonator leads.
4.Take care to prevent the cable from coming into contact
with any power or lighting cable or other electrical
apparatus
5.Himself couple the cable to the firing apparatus and before
doing so, see that all persons in the vicinity have taken
proper shelter.
6.After firing the shots and before entering the place of
firing, disconnect the cable from the firing apparatus.
Conti…..

27. MMR 163
Electric Shot firing

Where more than one shot are to be
fire at the same time
1.Care shall be taken that all connections are
properly made
2.All shots if fired belowground shall be
connected in series
3.The circuit shall be tested either for
electrical resistance or for continuity
before connecting it to the firing apparatus.
4.The cable to the shot firing apparatus shall
be connected last

28. 1. Blasting Cable MMR 163
Circular 23 Of 1960 & 70 of 1966
Cable for single shot firing
Two core cable, each core at least four
copper wires of not less than 0.018 inch in
diameter. For protection against
mechanical wear and damage P.V.C. 0.025
inch in thickness. The two cores twisted,
wormed and covered with a sheath of
cotton braid, tough rubber or P.V.C.
Cable for multi shot firing
Single-core cable, consisting of a
conductor of at least three copper wires
of not less than 0.036 inch in diameter,
insulated to withstand at least 250 volts,
and further protected against mechanical
wear and damage.

29. 2. Blasting Cable MMR 163
Circular 25 of 1974

Approval for the shot-firing cables
to be used in mine to several
manufacturers based on specification
No. 115 issued by the National Coal
Board, U.K. has been issued. As
Indian Standard Institution has now
published necessary specification for
the shot-firing Cables vide IS: 5950
of 1971, it shall be ensured that
while ordering shot-firing cables,
after 30th September, 1974, that
they are covered by a fresh approval
from this Directorate and in
compliance with IS : 5950 of 1971.

30. MMR 163 Exploder
Circular 4 of 1965, 05 of 1975 & 03 of 1987
Maintenance and repair of exploders
The agencies where repair work of various types of exploders
can be carried out are indicated below
Type of Exploder Agency for repair work
Schaffler—350 IDL Chemicals Ltd. Hyderabad
'Rihno' brand exploders M/s Electronic Equipment
Manufacturing Co. Calcutta
ME-6 (Six shot exploder) Jivon & Co. P Ltd, IEL Calcutta
ME—12(12 shot exploders) IEL ltd. Calcutta
25 Shot Sanjoy exploder M/s Sanjoy Industries Dhanbad
'Star' brand exploders M/s Electrical Equipment
Corporation New Delhi
25 Shot exploder of
M/s Swastik
M/s Swastik Mining Industries
Dhanbad

31. MMR 163 Exploder
Circular 43 of 1972

Servicing and repair of exploder
After any repair or replacement involving essential
parts such as condensers, resistances etc. in addition to
the tests at repairer's workshop the repaired exploder
shall be check-tested at the CMRS, Dhanbad only for
the following:
1. Duration of current impulse
2.Output Voltage
3.Residual current,
and a copy of the report of such check test shall be
furnished to the management and also forwarded to
the DGMS. A Usability Certificate shall also be given
with the exploder. Conti….

32. MMR 163 Exploder
Circular 43 of 1972

In case the check tests indicate
1.Duration of current impulse more than 4
millisecond,
2.Output voltage variation more than +1% of
rated voltage, or
3.Any residual current
the repaired exploder shall not be put into use
till the defects are fully rectified and rechecked
In case the defective micro switch/micro switches
are replaced by those identical with the original
micro switches and imported from makers of the
same

33. MMR 163
Circular 03 of 1973

Circuit Testers
Only one Circuit Tester namely 'GYRO' Ohm
Meter manufactured by M/s Gyro Laboratories
Pvt. Ltd., Bombay, has been approved by this
Directorate for the purpose of testing blasting
circuits in a safe manner in a mine.

34. MMR 163
Circular 07 of 1992
Use of circuit continuity tester during electric shot
firing in mines – FOR U/G

MMR 163
Circular 01 of 2000
Danger due to explosives during testing of
electric detonator
Managements are requested to comply with
provisions of the safety laws and safe
practices in usage of explosives to prevent
recurrence of such accident in future.

35. MMR 164
Taking shelter
Blaster shall not charge or fire a shot
1.Unless sufficient warning, by efficient signals is given over
the entire area falling within a radius of 300 m (danger
zone) an also he has ensured that all persons within such
area have taken proper shelter.
2.Where any part of a public road or railway lies within the
danger zone, two persons are posted, one in either
direction at the two extreme points of such road or
railway who have, by an efficient system of telephonic
communication or hooter clearance of traffic to the
blaster and have also warned the passers.
3.Provided that if blasting is done in such a manner approved
in writing, by the Chief Inspector or Regional Inspector ,
that the flying fragments from blasting cannot project
beyond a distance of 10 m from the place of firing, the
provisions of 1 & 2 need not be complied with.

Conti…..

36. MMR 164
Taking shelter
In the case of an opencast working, where any permanent
building or structure of permanent nature, not belonging
to the owner, lies within the danger zone, the aggregate
maximum charge in all the holes fired at one time shall not
exceed 2 Kg unless permitted in writing by the Chief
Inspector of the Regional Inspector.

Provided that if blasting is done with delay detonators or
other means an that there is a delay of at least half a
second between successive shots fired, a maximum charge
of 2 Kg can be used in each hole.

Provided further that if the shortest distance from the
place of firing to any part of such building or structure is
less than 50 m irrespective of the amount of the charge,
no blasting shall be done except with the permission in
writing of the Chief Inspector or the Regional Inspector.

37. MMR 164 Taking Shelter
Circular 08 of 1982
Danger from blasting operations in o/c
workings
Accidents due to human failure
Accidents owing to failure of certain types
of structures to provide adequate shelter
within the danger zone
From the above it may appear that there is a case
for revising the limit of danger zone from 300 m
to at least 500 m and for prescribing that all
those who must remain within the danger zone at
the time of blasting should take shelter in
'substantially built' shelters.

38. MMR 164 Taking Shelter
Circular 11 of 1961
Hours of blasting in opencast mines
It is highly desirable that all blasting operations
(including carrying of explosives into the working
area, preparation of priming cartridges including
soaking LOX cartridges, charging of shot holes,
stemming of shot holes and firing) in opencast
workings should be restricted to periods when
the workings are generally clear of other work
persons, i.e. the period between two consecutive
shifts or at beginning or end of a working shift.
Where blasting is carried on in adjacent blocks or
areas, the minimum distance between such blocks
should not be less than 300 m.

39. MMR 164 Taking Shelter
Circular 01 of 1967

Simultaneous blasting with fuse in opencast
workings
where a number of blasters are employed in
proximity to each other (i.e., 300 m) only one
blaster at time may fire shots, and the interval
between two blasters firing shots should not be
less than 30 minutes.

40. MMR 164 Taking Shelter
Circular 08 of 1976

Blasting in quarries beyond day light hours
Blasting Operation shall not be carried out
beyond day lights
If shot fired after day hours, should be muffled
so that flying fragments from blasting cannot
project beyond a distance of 10 m from the
place of blasting.

41. MMR 164 Taking Shelter
Circular 15 of 1982
In order to avoid accidents following
precautions may be taken
1.Boreholes drilled for exploration or tapping water
etc. shall be shown on ― the plan or tracing of the
workings provided to supervisory officials.
2.The approach to the end of borehole shall be
fenced off before blasting to prevent any person
coming in direct line of the borehole.
3.No shot hole shall be drilled within 0.6 m of any
borehole.
4.The supervisory official viz. Asstt. Manager/Foreman
shall, where applicable personally brief the Mate and
Blasters on the necessity of taking precautions at 2
and 3 above.

42. Circular on
Ground Vibration MMR 164
Damage of structures due to blast induced
ground vibrations in the mining areas
As only 20-30% of energy of commercial explosives
used in mines is utilized for fragmenting the rock,
the rest of the energy is transmitted through the
earth in the form of ground vibrations resulting in
damage to the surrounding structures.

43. Damage criteria MMR 164

S. No. Category Description of damage
1 No appreciable
damage
No formation of noticeable cracks.
2 Threshold damage Formation of fine cracks, fall of
plaster, opening & lengthening of old
cracks, loosening of joints, dis-lodging
of loose objects etc.
3 Minor damage Superficial not affecting the strength
of structure(s). Hair line cracks in
masonary around openings near
partition, broken windows. Fall of
loose mortar etc.
4 Major damage Formation of several large cracks,
serious weakening of structures,
shifting of foundation, fall of masonary,
ruptures of opening vaults etc.

44. Measurement of blast induced ground
vibrations
Tri axial transducers for recording blast vibration shall
have a linear frequency up to 500 Hz. and capable of
recording particle velocity up to 100mm/s.
A minimum of 15 points of observations corresponding
to a minimum of 10 blasts shall be made for better
prediction with a high index of determination.
The square root scale distance shall be used for analysis
and interpretation of data when blasting is done on
surface and measurements are taken on the surface

45. Permissible Peak Particle Velocity (ppv) at
the foundation level of structures in Mining
Areas in mm/s ( Circular 7 of 1997)
Type of structure Dominant excitation frequency, Hz.

<8 Hz. 8-25 Hz. >25 Hz.
(A) Buildings/structures not belonging to the owner
(i) Domestic houses/structures
(Kuccha, Brick & cement)
5 10 15
(ii) Industrial Buildings (R.C.C. &
Framed structures)
10 20 25
(iii) Objects of historical importance -
& sensitive structures
2 5 10
(B) Buildings belonging to owner with limited span of life
(i) Domestic houses/structures
(Kuccha, Brick & cement)
10 15 25
(ii) Industrial Buildings (R.C.C. &
Framed Structures)
15 25 50

46. MMR 166
Inspections after shot firing
After a shot has been fired, no person other than the
blaster or any other competent person holding a
Manger’s or Foreman’s Certificate appointed for the
purpose by the Manager shall enter, or allow any
other person to enter, the place until the area is free
from dust, smoke or fumes.
In opencast workings, after shots have been fired, an
all clear signal shall be given except in the case of a
misfire.
After shots have been fired, all persons engaged in
clearing mineral, shall look for unexploded cartridges
and detonators. If such a cartridge and detonator is
found, it shall be removed and shall as soon as
possible be handed over to a blaster or other official.

47. MMR 167
Misfires
The number of shots which explode shall, unless
shots are fired electrically or by igniter cord, be
counted by the blaster and another competent
person authorized for the purpose and unless it is
certain that all the shots have been exploded, no
person shall re-enter or be permitted to re-enter
the place until 30 min., where shots are fired
electrically 5 min.
In the event of a misfire, the entrance or entrances
to the working place shall be barricaded or fenced.
In opencast workings, it shall be sufficient to
mark the place of the misfire with a red flag.

48. MMR 167
Misfires
In the event of a misfire, the tamping may be
sludge out with compressed air or water under
pressure The hole shall there after be
reprimand and fired.
If the misfire contains a detonator, the leads or
fuse thereof shall be attached by a string to the
shot firing cable or some distinctive marker.
A relieving hole drilled in such a direction that
at no point shall it be nearer than 30 cm from
the misfired hole.

49. MMR 167
Misfires
After a relieving shot has been fired, a careful
search for cartridges and detonators, if any, shall
be made in the presence of the blaster.
When a misfired shot is not found, or when a
misfired shot is not relieved or re blasted, the
blaster shall, before leaving the mine, give
information of the failure to such official as may
relieve or take over charge from him. also
record, in a bound paged book.
The blaster of the next shifts shall locate an
re blast the misfired hole.

50. MMR 168
Precaution in as of sockets etc.
Before the commencement of drilling in any
working place, the competent person in
charge of the place shall see that all looser
rock is removed from the face and the area
lying within a radius of 2 m of the proposed
Shot hole is thoroughly cleaned or washed
down with water and carefully examined for
the presence of misfires or sockets.
If any socket is found, it shall be dealt with in
the manner prescribed in R 167.

51. Circular on MMR 168
Circular 22 of 1973
Precautions in case of sockets
boulders should be thoroughly cleaned or
washed down with water and a careful
examination made by a competent person for
the presence of misfires or sockets.
Circular 22 of 1973
Socket to be plugged
During Drilling keep the misfired hole or the
socket plugged by a wooden plug

52. MMR 169
Duties of blaster at the end of his shift
Immediately after the end of his shift, the
blaster –
(a) shall return all unused explosive to the
magazine
(b) shall record, in a bound paged book kept
for the purpose, the quantity or explosive
taken, used an returned, the places where
shots were fired and the number of shots
fired by him, and misfires, if any. Every such
entry shall be signed and dated by him.

53. MMR 170
General precautions regarding explosives
No person, whilst handling explosives or engaged
or assisting in the preparation of charges or in
the charging of holes, shall smoke or carry or use
a light other than an enclosed light, electric torch
or lamp.
No person shall take any light other than an
enclosed light, electric torch or lamp into any
explosive magazine or store or premises.
Any person finding any explosives in or about a
mine shall deposit the same in the magazine.
Every such occurrence shall be brought to the
notice of the manager in writing.