nitro nobel electric initiation

Electric Initiation Users manual Standard Operation Procedure

for use of electric detonators in demining operations.

TRIO ul.Glavna 18a/L30, 11080 ZEMU, S&MN

1

Electric Initiation Users manual Standard Operation Procedure

for use of electric detonators in demining operations.

This users manual is intended as a guide for all persons using electric initiation when de-stroying mines and unexploded ordnance (UXO). It gives knowledge about the range of possibilities that a well designed and developed ini-tiation system can provide and also points out the risks that may be present when using electric initiation. This manual only describes products and systems from TRIO. The detonators presented in this manual are solely intended for initiation of explosives. In case the detonator is placed free on ground it must be well covered with sand or similar material. The detonators described in this manual must not be used in gassy environments such as in coalmines and other work sites where explosive gasses may occur.

Content Page 1 Detonator description 3 Group 1 detonator (A/S/NT) 5 Group 1a detonator (U) 5 Group 2 detonator (VA) 5 Group 3 detonator (HU/XS) 6 2 Electric resistance and characteristic for the different detona-

tors groups 6

3 Technical data for electric detonators from Dyno Nobel 6 4 Colour coding of electric detonators 7 5 Marking on the detonators shell 8 6 Joining detonators in a round 8 7 MS and HS detonators 9 8 Testing and firing the round 9 9 Testing electric circuits 10 10 Resistance meter Beetohm 11 11 Blasting machine CB 20 VA and CB 400 NT 12 12 Blasting machine Beethoven MK 22/3 16 13 Faultfinding 19 14 Firing cable and connecting wire 20 15 Hazards in connection with electric initiation 21 16 Destruction of detonators 24 17 Misfire procedure 25 18 Certificates 26

2

Questions: trioPost-box 1401 Smedeland 7 DK-2600 Glostrup Denmark

Tel. ++381 11 316 72 84Telefax++381 11 307 68 97

E-mail [email protected]

Dyno Nobel Danmark A/S, 1/2004

3

1. Detonator description The principle of operation of an electric detonator is that, when a high enough electric current is passed through the leg wires, a bridge wire is heated in the fuse head, which then deflagrates and initiates the de-lay element which in turn initiates the explosive in bottom of the detonator after a time determined by the length and content of the delay element. Dyno Nobels electric detonators have a strength rat-ing of No. 8 (according to Prior test 10) for the safe initiation of cap sensitive explosives and primers. They are known as NPED*-detonators (Non Primary Explosive Detonator), this means they do not contain any primary explosive (e.g. lead azide). NPED-detonators are considerably less sensitive to impact and rough handling than detonators that contain pri-mary explosive. The sensitive lead azide in a conventional detonator is replaced by an I-element in which PETN is enclosed in a steel tube. In the I-element a deflagration turns into a detonation, which in turn initiates the base charge. The detonator shell, which is made of aluminum, con-tains, in addition to the secondary explosive in the I-element, a base charge of RDX (also a secondary ex-plosive) which initiates the explosive in contact with the detonator. The total amount of explosives in the detonator is approx. 1 g. In the delay element the detonation is delayed pyrotechnically for a predeter-mined time after the firing impulse has reached the detonator. The delay times vary in steps between 25 ms (0.025 sec.) and 5000 ms (5 sec.). Enclosing the fuse head is an electrostatic protective sleeve that decreases the risk of unintentional initiation due to static discharge. The detonator is fitted with a sealing plug to make it water resistant.

Electric detonators are manufactured with two types of delay, millisecond delay (MS) and half-second delay (HS). In the MS-detonators the delay time increases in increments of 25 ms between each period number while the increment is 500 ms in the HS-detonators Elec-tric. HS-detonators are designed for use in underground operations. HS-detonators should be used in surface operations as the delay times are too long and can cause fly rock, which can damage explosives charges placed near to. HS-detonators should only be used for de-struction of UXO buried in stacks. HS-detonators can be replaced by non-electric initiation systems such as NONEL LP, which reduce the risk of unintentional initiation. Electric MS-detonators are used in surface operations and mostly for single shot or in smaller operations. When placed on the surface only detonators with one delay number should be used. * US patent No. 4.727.808


4

The delay time of an electric detonator is the sum of the delays in the delay element, the intermediate composition, used for fine-tuning of the accurate delay time, and the I-element. For safe and successful blasting with electric detonators the following is needed:

1. A blasting machine capable of firing the size of the round with the type of detona-tors being used.

2. Knowledge of electric hazards at the worksite and ensuring they are eliminated. 3. That each series in series/parallel blasts are of the same size. Careful connection of

lead wires and scrupulous testing of the different parts of the round. The design of the firing pattern depends on the number of detonators in the round and the type of blasting machine that is used. Generally rounds with less than 50 detonators can be connected in one series. Larger rounds can be divided into several series which are then connected together in parallel. The appropriate authority in the country where it is used must approve the source of en-ergy that is used for the initiation of an electric blast. A capacitor-blasting machine, which is capable of firing the number of detonators in the round, is the most reliable means of initiation. Knowledge of the hazards at the worksite that could cause unintentional initiation of one or several electric detonators is absolutely necessary in order to be able to eliminate them. See page 23 for the risks that may occur and recommendations for their elimination. It is important to take extreme care when firing with electric detonators. Lack of attention to detail can result in damage to property and injury to people. All electrical connections must be well made and all joints well insulated. Bare electric wires must not come into contact with earth. The resistance of all series must be checked and must tally with the cal-culated values. Each series in a round connected in series/parallel should have the same resistance and only approved connecting wire and firing cable must be used. For a successful simultaneous initiation of a great number of detonators, sufficient electri-cal power must be delivered to all detonators within a few milliseconds. The time required to heat up the bridge wire until the fuse head deflagrates is a function of the voltage and the current. It is important that all detonators in a firing circuit are initiated instantaneously. If one detonator in the round fires before any other the circuit breaks and one or several detona-tors will not get the firing impulse and misfires will occur. Therefore, Dyno Nobels instantaneous detonators have a very short delay time, which is obtained by a pyrotechnical batch, which is pressed directly into the detonator. Due to the very short delay time, there is no risk that the firing current breaks the circuit too early in a circuit with several detonators connected in series. Therefore, instantaneous detonators should not be connected in series. Different types of detonators have different firing properties and must not be used in the same round. The same is true for detonators from different manufacturers.


5

Electric detonators are classified in 4 Groups or 4 Classes depending on their electric prop-erties. The denomination Group is the traditional Nordic conception with the subdivisions 1, 1A, 2 and 3. In the proposed new European Standard (prEN 13763-1) the denomination is Class with subdivisions 1, 2, 3, 4. In this manual the denomination Group will be used.

Nordic denomination Older denomination European denomination Group 1 Type A/S/NT Class 1 Group 1a Type U Class 2 Group 2 Type VA Class 3 Group 3 Type HU/XS Class 4

Group 1 detonator (type A/S/NT) Group 1 detonator (called NT-detonator by Dyno Nobel) is a conventional electric detona-tor. In NATO countries a group 1 detonator is named L1A2 electric detonator. Electric detonator type A and L1A2 are slightly more sensitive than the type NT. The no fire current is < 0.25 A. A minimum of 0.6 A firing current is required to initiate one Group 1 detonator and a minimum of 1.0 A is required to reliably initiate a series of Group 1 detonators. Group 1A detonator (type U) Group 1A detonators are somewhat safer in hazardous situations than Group 1 detonators. The no fire current is < 0.45 A. A minimum of 1.0 A firing current is required to fire one Group 1A detonator and a mini-mum of 1.5 A is required to initiate a series of Group 1A detonators. Group 2 detonator (type VA) Group 2 detonators are detonators with a high degree of safety. Even though VA detona-tors are much safer in the presence of electrical hazards than Group 1 detonators, safety precautions must still be taken close to strong radio transmitters, radar, power lines over 70 kV and during thunderstorms. No fire current is < 1.2 A. A minimum of 2.2 A is required to fire one VA detonator and a minimum of 3.5 A is re-quired to fire a series of VA detonators. The resistance of VA detonators is independent of leg wire length and is 3.6 + 0.3 at + 20 C. Note that the resistance depends on the temperature and decreases when the temperature falls. The leg wires can be of different material (iron, brass or copper) depending on leg wire length. Therefore the temperature dependence is different for different leg wire lengths.


6

Group 3 detonator (type HU/XS) The HU/XS detonator is a detonator with a very high degree of safety against electric haz-ards. No fire current is < 4.0 A. A minimum of 6.0 A is required to fire one Group 3 detonator and a minimum of 25 A is required to fire a series of Group 3 detonators. Dyno Nobels Group 3 detonators are not included in the CE certification according to di-rective 93/15/EEG and may therefore not be sold within EU without special per-mission. These products are included in this manual only for information and for markets outside EU as well as for customers with requisite permits. 2. Electric resistance and characteristic for the different detona-tors groups

Type Characteristic A, S

L1A2 NT

(Group 1) F, U

(Group 1a) VA

(Group 2) HU, XS

(Group 3) Fuse head resis-tance R in (Ohm)

0,9-1,4

0,9-1,4

0,4-0,9

0,15-0,25

0,04-0,09

Resistance incl. wire R in (Ohm)

1-5

1-5

0,6-3,5

3,3-3,9 *

0,5-1,0

Firing pulse Ktu in mJ/ Kt in mJ/

0,8 3

2,5 5,5

8,0 16

80 140

1100 2500

Firing current Itu in A Ik in A

0,18 0,8

0,28 1,1

0,45 1,5

1,3 3,5

4 25

Firing voltage Utu in Volt

0,2

0,3

0,3

4,3

2,0

* The resistance does not depend on the length of the wire for this type of detonator. Ktu Firing impulse, lower limit, corresponding to 0.01 % firing frequency (mJ/) Kt Firing impulse, upper limit, corresponding to 99.99 % firing frequency (mJ/) Itu Firing current, lower limit, corresponding to 0.01 % firing frequency (A) Ik Series firing current, corresponding to 99.99 % firing frequency (A) Utu Firing voltage, lower limit, following Ohms Law Utu = R Itu

3. Technical data for electric detonators from Dyno Nobel. Recommended working temperature: -25 C - + 50C Recommended storage conditions: Normal room temperature, occasionally max + 50C

at max. RH 50 %. The magazines should be well ventilated as well.

Maximum hydrostatic water pressure: 3 bar during 7 days Tensile strength, single wire: 4 kg max + 50C Tensile strength, joint detonator/leg wires: 4 kg during 2 minutes up to + 50C The electric detonators are packed in plastic bags. Dyno Nobel guarantees the function in 3 years from date of manufacture if package is unopened. Date of manufacture is given on box as well on a tag on every single detonator (year/month).


7

4. Color coding of electric detonators. Electric detonators are color coded by dif-ferent colors on the leg wires. Common for all groups is that one of MS-(millisecond) detonators leg wires is green and one of the HS-(half second) detonators leg wires is red. The instanta-neous detonator has one white leg wire.

Group 1 NT-instantaneous NT-MS NT-HS* Group 1A U-instantaneous U-MS U-HS* Group 2 VA-instantaneous VA-MS VA-HS* Group 3* XS/HU-instantaneous XS/HU-MS XS/HU-HS

Leg wire colors Yellow/white Yellow/green

Yellow/red

Red/white Red/green

Red/red

Grey/white Grey/green

Grey/red

Blue/white Blue/green

Blue/red

* NOTE that Dyno Nobels HS-detonators and Group 3 detonators are not certified under EU directive 93/15/EEG. The above color code is the code used by Dyno Nobel Europe and based on interna-tional practice. That does not mean that all manufacturers follow this practice.

NEVER USE DETONATORS FROM DIFFERENT GROUPS

IN THE SAME ROUND. IT WILL MOST PROBABLY CAUSE MISFIRES AS THE DIFFERENT GROUPS HAVE

DIFFERENT ELECTRICAL PROPERTIES. FOR THE SAME REASON DETONATORS FROM DIFFERENT MANUFAC-

TURERS MUST NOT BE USED IN THE SAME ROUND.


8

5. Marking on the detonators shell. Dyno Nobels detonators are marked with the delay time. Therefore it is possible to deduce which period number a detonator has even though the identification tape has disappeared during the charging op-eration. For example, the marking 500 ms shows that it is an MS detonator No. 20. If it states 25 ms is it a MS detonator No.1

6. Joining detonators in a round. When connecting a round, it is important that bare leg wires or joints do not come into contact with earth or with each other. In contact with earth, the initiation current may leak into the earth and only a part of the round may fire. If joints come in con-tact with each other the initiation current may take a shortcut with the same conse-quences. For this reason all detonators manufac-tured by Dyno Nobel are fitted with a connecting sleeve fixed to one of the leg wires. For transport the other leg wire is loosely inserted into the connecting sleeve. When connecting the circuit the end of the wire with no insulation from one detonator is inserted into the connect-ing sleeve of the next. The connecting sleeve is twisted 5 - 6 turns and a good connection is obtained. For electric detonators that are not sup-plied with connecting sleeves there are available grease filled connecting sleeves are available. These connecting sleeves are especially useful in wet operations. All detonators manufactured by Dyno Nobel Europe are fitted with connecting sleeves as standard.


9

7. MS and HS detonators. Dyno Nobel manufactures three series of electric detonators:

- MS-series - Extended MS-series - HS-series

MS series detonators are intended use in bench and trench blasting and are suitable for demining and bulk demolition of UXO as well. The extended MS-series detonators are used in underground operations and bench blasting with large burdens (8 - 10 m). HS-series detonators are intended only for underground blasting or for bulk demolition of UXO.

Delay times: MS-series: No. 0 Instantaneous No. 1 25 ms HS-series: No. 0 25 ms No. 2 1000 ms (1 second) No. 4 2000 ms (2 second) No. 6 3000 ms (3 second) No. 8 4000 ms (4 second) No. 10 5000 ms (5 second)

8. Testing and firing the round. The measuring instruments and blasting machines that are used for the testing and firing of electric rounds must in some countries be approved before use.

The use of batteries or power from mains is strictly prohibited. Capacitor blasting machines have proved to be very reliable even under severe working conditions. The introduction of Group 2 and Group 3 detonators with high in-built safety increased the demand for blasting machines with high capacity. The blasting machines typ TRIO are CE certified in accordance with EMC and LVD directives.


10

9. Testing electric circuits. Electric detonator rounds may be connected in series, in parallel or in a combination of series and parallel connections. Which method of connection is used depends on the size of the rounds and the blasting ma-chine available. When a firing circuit is connected in series the measuring procedure is simple. Just multiply the number of detonators by the resistance of one detonator. The measured value should be the same as the theoretical calculation. When the firing circuit is connected in se-ries/parallel the connection procedure is somewhat more complicated.

Connection in series.

Each series in the round must be of the same size and the resistance of each series must not vary by more than 5% between highest and lowest value. It is best if all series contain the same number of detonators. When the series are connected in parallel the resistance becomes lower as the area through which the firing current is to go through increases. If we have two series the area is doubled and the resis-tance is half of that of one series. With 3 series connected in parallel the resistance will be one third and so on.

Connection in series/parallel

Resistance after connection in parallel = SERIESOFNUMBER

RESISTANCE

In the top example there are 18 VA detonators connected in one series. The resistance is then 18 x 3.6 = 65 .

In the lower example there are 30 VA detonators connected in 2 series. The resistance in each series is 15 x 3.6 = 54 . The resistance of the round connected in parallel is then 54/2 = 27 . Note that the resistance of the firing cable is added on to these values when connected.


11

10. Resistance meter Beetohm. dodati trio sliku

Test instruments used to check electric rounds. The use of electricians resistance meter is strictly forbidden, as the measuring current is far too high. Beetohm is an in-strument for measurement of the resistance in individual detonator and detonators con-nected in series and rounds connected in series/parallel. The test instrument Beetohm is digital and starts and selects measuring range automati-cally, the blaster only needs to connect the round (or part of the round) to the terminals of the instrument and read the result.

The displayed value is automatically rounded off to the accuracy needed in prac-tical blasting work. Beetohm has an in-built resistor for the self-test function. Pressing the black button tests Beetohm. The instrument is powered by a 9V battery and displays when it is time for a replace-ment battery to be fitted. When blasting with heavy covering material it is good practice to test the circuit after the placement of each mat. In that way discon-tinuities in the circuit are discovered quickly and can be corrected.

Technical data for Beetohm

Range of resistance (R-measurement): 0-1.999,9 Measuring current: 1 mA Working temperature: -10 C to + 50 C Size (l x w x h) 147 x 85 x 38,5 mm Weight: 0,5 kg Battery: 1 p.c. 9 V battery 6F22

Measuring with Beetohm Connect the shot firing cables to the two terminals. Press the switch button to see the cir-cuit resistance displayed. An open circuit or resistance above 1.999,9 is displayed as a 1on the left hand side of the display. When the battery requires replacement, a battery symbol will appear on the display. To replace the battery, remove the case screws and lid, this will allow access to the battery compartment.


12

11. Blasting machine CB 20 VA and CB 400 NT. dodati trio sliku

The CB is a capacitor-blasting machine de-signed for initiation of up to 20 VA detona-tors connected in one series with a firing cable that has a maximum resistance of 5. The blasting machine is battery powered and requires a two handed operation to avoid unintended initiation of the round. CB is delivered with rechargeable batteries that are located in the handle. The batteries are charged by connecting the terminals of the blasting machine to a DC source of 12 or 14 V, i.e. the cigarette lighter outlet in a car or to a battery charger.

In case of emergency ordinary batteries can replace the rechargeable batteries. (Do not try to recharge ordinary batteries). The control panel of the blasting machine has three lamps that indicate:

1. If the batteries are sufficiently charged.

2. That the resistance in one series is within the capacity of the blasting machine.

3. That the capacitor is charged and ready for initiation.

Technical data for CB

Capacity, max number of detonators: Se table on next page Max. resistance of the round, group 2 (type VA) 77 Max. resistance of the round, group 1 (type NT) 430 Charging time: Approx. 15 sec. Capacitance: 200F Firing current: 540 V Working temperature: -25 C to + 55 C Weight: 0,65 kg Size (l x w x h) 245 x 65 x 75 mm


13

Operating instructions for blasting machines CB 20 VA and CB400NT The CB 20 VA is adapted to Group 2 detonators and the CB 400 NT is adapted to Group 1 and 1a detonators. General CB 20 VA and CB 400 NT is a capacitor-blasting machine designed for the initiation of 20 Group2 (type VA) detonators in one series alternatively 120 Group la detonators in 3 series with a firing cables resistance of 5 . The firing machine requires a two handed operation to avoid unintended initiation of the round. With in-built test functions the charge level of the batteries may be checked as well as if the resistance of the round is within the blasting machines capacity. The blasting machine must not be used as circuit tester for the round. Built-in batteries power the blasting machine. As standard CB 20 VA and CB 400 NT are delivered with rechargeable Ni-Cad batteries. The capacity of CB 20 VA and CB 400 NT for different types of detonators. For the types of detonators that have different resistance among them, also the total permit-ted resistance is stated. Group 1 (type A/S/NT)

Number of parallel

series

1 2 3 4

Number of detonators per series

170 140 120 100

Totalnumber ofdetonators

170280360400

Maximumresistance

per series,

425350300250

Group 1, A/S/NT detonators. CB can initiate up to 170 detonators in one series and 400 in 4 parallel series. In the table on the left the following data has been used: Firing current < 1 A, firing impulse < 5 mWs/. The resistance of each detonator is as-sumed to be 2.5 and the firing cable resistance to be 5 . The resistance of Group 1 detonators depends on the leg wire length.

Group 1a (type U)

Number of parallel

series

1 2 3


70 50 40


70100120

Maximumresistance

per series,

245175140

Group 1A, U detonators. When calculating the firing capacity of CB the following data has been used: Firing current < 1.5 A, firing impulse < 16 mWs/. The resistance of each detonator is as-sumed to be 3.5 and the firing cable resistance to be 5 . The resistance of Group 1A detonators depends on the leg wire length.

Group 2 (type VA)

Number of parallel

series

1


20


20

Maximumresistance

per series,

72

Group 2, VA detonators. CB can initiate up to 20 detonators. In the table on the left the following data has been used: Firing current < 3.5 A, firing impulse < 140 mWs/. The resistance of each detonator is as-sumed to be 3.5 and the firing cable resistance to be 5 . The resistance of Group 2 detonators is independent of leg wire length.


14

Group 3 (type HU/XS) Number

of parallel series

1 1 1


3 2 1

Leg wire length, m

4 6

10

Maximumresistance

per series,

1.81.81.8

Group 3, HU/XS detonators CB can initiate up to 3 HU/XS detona-tors In the table on the left, the follow-ing data have been used: Firing current < 25 A, firing impulse < 2500 mWs/. The resistance of each detonator is assumed to 0.6 and the firing cable resistance 5 . HU/XS detonators are connected only in a sin-gle series circuit. The resistance of Group 3 detonators depends on the leg wire length.

The electric detonators in the round must all be of the same type and the lowest period number must be No.1 Instantaneous detonators must not be used in rounds connected in series as they may break the firing circuit too early. Repair Any repair to the blasting machine must be made by a person who has knowledge and ex-perience of the electrical, mechanical and safety requirements (standards) that applies to the machine. If the machine has been opened up it is of utmost importance that the sealing is made cor-rectly when re-assembling. Battery testing Press the RED button TESTING. The lamp BATT shall light up. If the lamp does not light up, the batteries must be recharged at the earliest opportunity, or if dry cell batteries are used they should be replaced. NOTE! If the lamp BATT does not light up or if it goes out during the charging operation, the machine can be used only if the lamp CHARGE lights up within 30 sec after the green button CHARGING being pressed. The normal charging time to reach firing voltage is approx. 15 sec. If the lamp CHARGE does not light up within 30 sec after the green button CHARGING being pressed, the batteries must be recharged (or replaced) before the machine is used. Charging the batteries The batteries are charged by connecting the blasting machine to 12 -14 V DC, e.g. a car battery. Observe the polarity according to the marking on the terminals of the blasting ma-chine. The green lamp BATT lights up to indicate that the batteries are being charged. The charg-ing time for depleted batteries is approx. 14 hours. Replacement of batteries Unscrewing the battery cover on the handle of the blasting machine makes battery pack or battery holder replacement of batteries. When changing rechargeable Ni-MH, 4.8 V and 12 mAh, battery pack or to holder for dry cell the connecting cables must be detached from the old battery pack and soldered to the new pack or battery holder. If dry cells are used instead of rechargeable Ni-Cad batteries they must be of Alkaline type and placed in the battery holder according to instruction in the holder. Note! Do not recharge dry cell batteries.


15

Instruction DANGEROUS VOLTAGE! Do not touch the terminals and firing cable when firing. Max. voltage 550 V. Firing 1. First step: Evacuate the danger zone. 2. Connect the firing cable to the terminals by introducing the cables both ends into the

holes on top of the blasting machine at the same time, as the terminals buttons are kept depressed.

3. Press the red button TESTING The lamp ROUND shall light up and remain lit as long as the button is depressed. Also the lamp BATT lights up.

4. If the lamp ROUND lights up when the button is depressed and thereafter goes out, the resistance of the round is too high and no firing should be attempted as a misfire most probably will follow.

5. If the round test is satisfactory: release the button TESTING. Press the green button CHARGING and keep it pressed until the lamp CHARGE lights up. Charging time is approx. 15 sec.

6. FIRE the round by pressing the RED button FIRING while the green charging button is kept depressed.

7. Disconnect the firing cable.


16

13. Blasting machine Beethoven MK 22/3

The Beethoven MK 22/3 is a capacitor-blasting machine designed for initiation of electric detonators in above ground shot fir-ing applications especially where insensi-tive detonators are being used. All types of dc electric detonators can be initiated with consideration given to the output power generated by the MK 22/3.

The dc voltage required to initiate the deto-nators is supplied by a hand-operated gen-erator, which charges a capacitor to 950 V. The control panel on top of the blasting ma-chine has a lamp that indicates if the capaci-tor is sufficiently charged.

Technical data for Beethoven MK 22/3

Capacity, max number of detonators: Se table on next page Max. resistance of the round, group 2 (type VA) 65 Max. resistance of the round, group 1 (type NT) 255 Charging time: Approx. 7 sec. Capacitance: 28,5F Firing current: 950 V Working temperature: -25 C to + 55 C Weight: 4,5 kg Size (l x w x h) 275 x 94 x 217 mm


17

Operating instructions for blasting machines Beethoven MK 22/3 The Beethoven MK 22/3 is adapted to Group 2 detonators as well as Group 1 and 1a detonators. General Beethoven MK 22/3 is a capacitor-blasting machine designed for the initiation of 15 Group 2 (type VA) detonators in one series alternatively 80 Group la detonators in 2 series with a firing cables resistance of 5 . Firing is achieved by a two handed operation to avoid unintended initiation of the round. With in-built test functions the charge level of the capacitor may be checked. The capacity of Beethoven MK 22/3 for different types of detonators. For the types of detonators that have different resistance among them, also the total permit-ted resistance is stated. Group 1 (type A/S/NT)

Number of parallel

series

1 2 3 4


100 80 72 64


100160216256

Maximumresistance

per series,

250200180160

Group 1, A/S/NT detonators. In the table on the left the following data has been used: Firing current < 1 A, firing impulse < 5 mWs/. The resistance of each detonator is as-sumed to be 2.5 and the firing cable resistance to be 5 . The resistance of Group 1 detonators depends on the leg wire length.

Group 1a (type U)

Number of parallel

series

1 2


51 40


5180

Maximumresistance

per series,

180140

Group 1A, U detonators. When calculating the firing capacity the following data has been used: Firing current < 1.5 A, firing impulse < 16 mWs/. The resistance of each detonator is as-sumed to be 3.5 and the firing cable resistance to be 5 . The resistance of Group 1A detonators depends on the leg wire length.

Group 2 (type VA)

Number of parallel

series

1


15


15

Maximumresistance

per series,

60

Group 2, VA detonators. In the table on the left the following data has been used: Firing current < 3.5 A, firing impulse < 140 mWs/. The resistance of each detonator is as-sumed to be 3.5 and the firing cable resistance to be 5 . The resistance of Group 2 detonators is independent of leg wire length.


18

Group 3 (type HU/XS) Number

of parallel series

1 1


3 1

Leg wire length, m

4 6

Maximumresistance

per series,

1.81.8

Group 3, HU/XS detonators In the table on the left, the following data have been used: Firing current < 25 A, firing impulse < 2500 mWs/. The resistance of each detonator is assumed to 0.6 and the firing cable resistance 5 . HU/XS detonators are connected only in a sin-gle series circuit. The resistance of Group 3 detonators depends on the leg wire length.

The electric detonators in the round must all be of the same type and the lowest period number must be No.1 Instantaneous detonators must not be used in rounds connected in series as they may break the firing circuit too early. Repair Any repair to the blasting machine must be made by a person who has knowledge and ex-perience of the electrical, mechanical and safety requirements (standards) that applies to the machine. If the machine has been opened up it is of utmost importance that the sealing is made cor-rectly when re-assembling. Instruction DANGEROUS VOLTAGE! Do not touch the terminals and firing cable when firing. Max. voltage 950 V. Firing 1. First step: Evacuate the danger zone. 2. Connect the firing cable to the terminals by introducing the cables both ends into the

holes on front of the blasting machine. 3. Depress the Green button CHARGING and keep it pressed whilst turning the genera-

tor handle. 4. When the neon indicator lights pressing the RED button FIRING while the green

charging button is kept depressed fires the exploder. 5. Disconnect the firing cable. The exploder becomes automatically safe if the Green charge button CHARGING is re-leased at any time.


19

13. Faultfinding. Discontinuities After the round has been charged and connected it may occur that the resistance meter shows infinite resistance (it shows nothing), which means there is a break in the circuit. This can happen due to carelessly made joint, or a broken wire, or that a detonator is dam-aged or faulty. (If the detonator is damaged it must be replaced. Therefore it is a good prac-tice to check the circuit before adding the stemming. When measuring connected series it is important that the measured reading is the same as the calculated value. If the reading is higher than expected it is an indication that one or several series are not correctly connected or there is a break in one or several circuits. A lower resistance in a round or a series than the calculated value indicates that all detonators are not connected or that the measuring current has short circuited If wires become damaged when using blast mats the damaged wires could short circuit giving rise to earth faults where the measur-ing or firing current could bypass some detonators. To identify breaks in a circuit a resistance me-ter is used. The circuit is divided in two and each circuit is measured. The part that now is faulty is divided in two and the procedure re-peated until the fault is identified and then it may be corrected.

Earth faults Earth faults are leakage currents that go to earth allowing the firing current to miss out part of the circuit. This may happen when a leg wire of a detonator has been damaged during charging work, if not insulated joints are in contact with electrically conducting rocks or when connections lay under water. Special care should be observed when using heavy covering as damaged insulation on the leg wires may come in contact with the wires in the blasting mat and cause earth faults. When blasting with heavy covering it is im-portant to measure the blasting circuit after each mat is placed. If earth fault is discovered, the search for the fault is made in the same way as search for discontinuities.

When searching for earth faults a special meter must be used.


20

14. Firing cable and connecting wire

The firing cable is used to connect the electric round to the blasting machine. Resistance in the firing cable should be as low as possible as high firing cable resistance will decrease the ca-pacity of the blasting machine. The color of the firing cable should be such that it may not be mixed up with other cables on the work site. Competent persons may only repair the fir-ing cable.

Connecting wire is used to connect series that shall be con-nected in parallel and to connect the round to the firing cable. The connecting wire is a single, well insu-lated, wire with low resistance. If the resis-tance is too high it may affect the capacity of the blasting machine, reducing the num-bers of detonators that may be connected in the circuit. The connecting wire should be used only once. Used connecting wire may cause misfires.

Technical data for firing cable

Technical data for connecting wire

Type Wire

area mm

Insula-tion

thickness mm

Resis-tance per

100 m

Type Wire area mm

Insula-tion

thickness mm

Resis-tance per

100 m

REXV 2 x 1,50 0,8 + 1,3 2,5 ELUB 0,64 0,60 5,6


21

15. Hazards in connection with electric initiation Safety distance to lightning. Thunderstorms are with no doubt the greatest risk in blasting due to its unpre-dictable nature and the high amount of en-ergy released. A lightning strike may have a voltage of over 1.000.000 V and a cur-rent of over 100.000 A. A direct lightning strike in a worksite using electric detona-tors will initiate one or several detonators in the round, but even a distant lightning strike constitutes a risk due to the high current flow. When a thunderstorm is ap-proaching, the worksite using explosives must be evacuated and guarded in the same way as when a blasting is to take place. Group 1

(type A/S/NT)

Group 1a (type U)

Group 2 (type VA)

Group 3 (type

HU/XS) 1000 m 800 m 200 m 150 m Safety distance in meter to thunderstorm

Safety blasting should be combined with a lightning warning system.

Safety distance to power lines Close to power lines and electric cables, it is always hazardous to do blasting with electric detonators. Power lines may cause unintentional initiation by flash-over, in-duced currents and through capacitive dis-charge. The risk may be reduced by: Placing the firing cable on dry ground. Not extending the firing cable parallel

to the power line or in loops. Avoiding that firing cable, connecting

wires or leg wires coming into contact with the earth.

When extending the firing cable from the round to the firing point, the cable ends should be short-circuited.

When connecting to the blasting machine, the cable must be insulated from any con-ductive object.


22

Safety distance to overhead power lines Voltage on

the wire (kV):

Group 1 (type A/S/NT)

Group 1a (type U)

Group 2 (type VA)

and Group 3

(type HU/XS) 0,4 - 6

7 - 12 13 - 24 25 - 52

53 - 72,5 72,6 - 123 124 - 245 > 245

20 50 70 100 200 200 200 200

5 22 40 40 70 85 110 180

5 5 5 6 6 10 12 16

Safety distance to buried electric power lines

Voltage on the wire

(kV):

Group 1 (type A/S/NT)

Group 1a (type U)

Group 2 (type VA)

and Group 3

(type HU/XS) 0,4 - 6

7 - 12 13 - 24 25 - 52

53 - 72,5 72,6 - 123 124 - 245 > 245

2 3 6 16 16 16 16 16

2 3 10 10 16 16 16 16

2 2 2 3 3 10 16 16

Safety distance to overhead power line is the horizontal distance

and to underground power line is the total distance. The safety distances are different in different countries due to national restrictions. The recommendation above is according to Swedish regulation AFS 1986:14 Sprngarbete and to Danish regulation BAR Bygge- og Anlg, BVL Sikkerhed ved sprngningsarbej-der. Stray currents may occur close to electric welding operations and a safety distance of 30 m should be considered. Close to operating power stations, stray currents occur and a non-electric firing method should be used.


23

Safety distance to radio-frequency radiation Radio transmitters or radar may accidentally initiate electric detonators during the charging operation. It is mainly stationary radio transmitters that constitute a problem and then mainly the large medium wave and long wave transmitters.

Safety distance in meter to radio-frequency radiation when blasting on the surface Effect Frequency Group 1

(Type A/S/NT)

Group 1a (Type U)

Group 2 (Type VA)

Group 3 (Type

HU/XS) 1 < 0.1 W 3 1 0 0.3 1 < 1 W 10 3 0 1 1 < 5 W 20 7 0 2 5 5 110 W (100 W) < 26 MHz 100 30 10 10 6 110 W 500 W < 26 MHz 100 100 W 1 kW 300 100 30 7 500 W 2.5 kW < 26 MHz 100 1 10 kW 1000 300 90 8 2.5 10 kW < 26 MHz 170 10 100 kW 3000 1000 300 100 400 kW 6000 2000 (800) *) 600 400 1000 kW 9000 3000 900 1 3 MW 15000 5000 (1700) *) 1500 2 5 110 W > 26 MHz 0.5 3 110 500 W > 26 MHz 10 4 > 500 W > 26 MHz 30

Safety distance in accordance with 4th Draft Technical "Report Preventation of inadvertent initiation of bridge wire electro-explosive devices by Radio frequency radiation" (GEL/602/-/1, CLCTC31 (sec) 317 August 1997) and the Swedish Board of Labours Sprngarbete (AFS 1986:14 of 20th August 1996). * Short, mid and long wave transmitters in Denmark. 1. Hand carried radio transmitters (e.g. GSM pocket mobile phone, wireless communication

to machinery). 2. Radio transmitter in cars e.g. police, taxi, GSM/UMTS mobile phone and mobile amateur

radio transmitters. 3. Stationery amateur radio transmitter and local radio transmitters. 4. Stationery civilian FM- or TV transmitter and transmitters for GSM/UMTS. 5. Stationery amateur radio transmitter, transmitters on vessels, radio beacon. 6. Stationery amateur radio transmitter, transmitters on vessels, radio beacon. 7. Transmitters on vessels. 8. Coast radio transmitters. In cars with radio-frequency radiation may electrical detonators be transported when they are placed in a way that radio transmission cannot initiate the detonators. Mobile phones cannot inadvertent initiate electrical detonators group 1a, group 2 and group 3 when they are in the original packaging from the manufacture. Special safety distances apply for blasting underground.


24

With regard to radar installations, contact should be taken with the owner for information about the danger zone. Static electricity can be built up during sand and snowstorms causing unintentional initia-tion. Static electricity can also build up during covering work with heavy mats under dry condi-tions. A person charged up with static electricity can constitute a risk to safety, especially when using Group 1 (type A/S/NT) detonators.

If safety distances cannot be obtained use non electrical firing systems.

16. Destruction of detonators. Detonators that are damaged or too old should not be used but must be destroyed. Small quantities of undamaged detonators may be disposed of by dropping them into a blasthole with explosive to be blasted. Cut the leg wires off and place the detonators into the blasthole one by one.

Taping them to or inserting them into an explosives cartridge that is to be fired may also destroy detonators. If the explosives cartridge is fired in open air, there is a risk of shrapnel being emitted along with a high air pressure wave.

If larger amounts are to be destroyed or if the detonators are damaged, contact Dyno Nobel or its representative.


25

17. Misfire procedure In the case of undetonated detonators being discovered after the blast, the following procedure can be used.

NOTE: Safety regulations in force must be followed.


26

18. Certificates Latest issue of declarations, certificates, safety data sheets etc. is available on request.

www.dynonobel.dk

nitro nobel electric initiation

Documents