WO2008146954A1

WO2008146954A1 - New non-electric 'pulkkot' parallel firing system

Info

Publication number: WO2008146954A1
Application number: PCT/KP2008/000016
Authority: WO
Inventors: In Mu Ryu; Nam Sok Ryu
Original assignee: Im, Chol Hun
Priority date: 2007-05-03
Filing date: 2008-05-03
Publication date: 2008-12-04

Abstract

Non-electric 'Pulkkot' parallel firing system is the shock tube firing system connected in the parallel way which affords the detonation both in a forward and a reverse direction. It comprises 'Pulkkot' tube detonating fuse, Parallel connector without a detonator, MS-delay socket, Detonator No.10 and Booster. The non-electric 'Pulkkot' parallel firing system can be used in a hole-to-hole delay blasting method that generates no excessive explosive sound and massive blasting gas exhaustion.

Description

New non-electric "PULKKOT" parallel firing system

Field of the Invention

The present invention relates to the new non-electric "Putkkof parallel firing system that provides high firing reliability and safety, but also saves cost.

Background of the Invention

At present from the world perspective, the non-electric firing system includes the DETONATING FUSE FIRING SYSTEM and the NONEL FIRING SYSTEM.

Detonating fuse firing system has the disadvantage of requiring a high cost and exhausting great quantities of explosive gas, but its circuit is connected in a parallel way that affords a high firing reliability.

Because of its high firing reliability, the detonating fuse firing system has been widely used till now in the massive open-pit bench and underground mining blasting. Safety and reliability is very important to the blasting system, so the efficient detonation of the circuit is regarded as an important factor.

The inventor mathematically calculated the firing reliabilities of the detonating fuse firing system and the Nonel firing system.

The circuit of the detonating fuse firing system is connected in the parallel way which makes the circuit detonated in a forward and a reverse direction. The mathematical modeling on the firing reliability of the circuit of the detonating fuse firing system is as follows :

Double line: p = (2r-r²)[2-(2r-r²)] Single line: p=(2r-r²) P: firing reliability of the circuit

R: firing reliability of the connector Nitro Nobei developed the "Nonel" firing system in 1970s. It has the advantage of low cost, but the firing reliability of the serial connection of the circuit is lower than the one of the parallel connection. Researches have been made to increase the firing reliability of such a serial connector. There are many patents in this regard including GB 214037, US 4722279, US 5771935, US 5398611 , US 5423263, US 5499581 , US 5703319, US 5594196, AU 18221/97A, US 5792975, US 6305287, US 6349648, WO 085818, WO 023314, 15,16, EP 1390324, US 200972, WO 111534, etc. The patents mentioned above are aimed at improving the firing reliability and are based on the design of the former serial connector that transmits detonating energy to the shock tube by the detonation of the detonator.

The circuit of the non-electric Nonel firing system is connected in the serial (event) way that affords a unidirectional detonation. The mathematical modeling on the firing reliability of the circuit of the Nonel firing system is as follows.

Single line: p = [r] ^{n + 1}

R: firing reliability of the connector n :number of connectors In the user's manual of the None! system, each blasting borehole comprises two connectors so as to enhance the firing reliability of the circuit. Its mathematical modeling is shown below.

Double line: p=[2r- r² ]ⁿ⁺¹

If the firing reliability of the Nonel connector increases by 10 times or 100 times, the firing reliability of the circuit is as follows respectively.

- firing reliability of the circuit of the Nonel firing system When original... r=0.99, n=35 P(single)=0.99~0.70, p(mean)=0.85 When 10 times... r=0.999, n=35 P(single)=0.999~0.970, p(mean)=0.985 When 100 times r=0.9999,n=35 P(single)=0.9999~0.9970 p(mean)-0.9985 - firing reliability of the circuit of the detonating fuse firing system. r=0.99, P(single)=0.9999 In the Nonel, Excel, Dynashock and CИHB firing systems, although the firing reliability of the serial connector increases by 1 time or 10 times or 100 times, the circuit may be misfired 1500 times, 150 times or 15 times respectively among 10000 times. The circuit of the detonating fuse firing system may be misfired 1 time among 10000 times, supposing that the firing reliability is the same as the original (1 time), so the firing reliability of the detonating fuse parallel circuit is 1500 times or 150 times or 15 times higher than the one of the Nonel serial circuit. Therefore in practices of open-pit bench blasting and underground mining blasting the detonating fuse firing system with high firing reliability of the circuit has been widely applied to the massive mining blasting till now, despite the fact that it has the disadvantage of high output of big fragments of rock because of losses of explosive energy due to the massive exhaustion of blasting gas.

As a way to increase the firing reliability of a blasting circuit in the massive open pit blasting, the user's manual of the Nonel system recommends to apply the Nonel system to each blasting borehole and the detonating fuse system to the circuit.

Description of the invention

The object of the invention is to provide a new non-electric parallel firing system that costs lower than Nonel system and has a high firing reliability of the circuit even with the shock tube.

The non-electric "Pulkkot" parallel firing system provides the high utilization coefficient of the explosive energy by applying the borehole bottom detonation and the hole-to-hole delay blasting, and comprises the configuration of parallel circuit that affords the high firing reliability.

The non-eJectric "Pulkkot" parallel firing system shown in Fig 1 has the multi-ringed circuit, which is being used in a new hole-to-hole delay blasting method developed by the inventor that generates no excessive explosive sound and massive gas exhaustion. The figures shown here represent the delay time of the circuit on earth surface and the delay time of the shock tube detonator placed in the blasting hole.

The circuit of the non-electric "Pulkkot" parallel firing system is connected in the parallel way which makes the circuit detonated in a forward and reverse direction and the mathematical modeling on firing reliability of this circuit is as follows.

Double line: p=(2r-r²)[2-(2r-r²)]+{1-[(2r-r²)(2-(2r-r²))](2r-r²)} Single line: p=(2r-r²)(1-r)+r The non-electric "Pulkkot" firing system comprises the "Pulkkot" shock tube, the connector without a detonator or a explosive charge, the MS delay socket, the detonator and the booster.

The MS delay socket and the booster can be optionally applied to the blasting according to the blasting situation. ① "Pulkkot" shock tube

"Pulkkot" shock tube is a low-energy detonating fuse that is used in transmitting Shockwaves. "Pulkkot" detonating tube transmits the blasting signal from one position to the other and provides the precise delay time control or timing. "Pulkkot" shock tube is made of the resin tube, in which the priming explosive charge is distributed along the length of the tube so as to maintain and transmit the Shockwave.

The priming explosive charge which takes the form of common powder or fine powder is adhered inside the tube. The priming explosive charge material comprises the oxidant such as perchlorate, permanganate or hydrogen peroxide and the secondary high energy explosive such as PETN, RDX, HMX, or TNT, and the metallic or non-metallic fine powder mixture such as aluminum or silicon.

One preferred priming explosive charge material is the mixture of hexogen (RDX) and Al or Si. The most common proportion of the composition is around 70-85% of hexogen and 15-30% of Al or Si.

The resin tube can be a single tube or two or three layered tube, which comprises the inner layer and the outer layers. The single resin tube can be made by injecting only polyethylene resin or the mixture of 2 - 5 different resins. The two or three layered resin tube comprises the inner tube, the most inside one, the resin of which has a high adherence to the priming explosive charge and the outer tubes, the resin of which has a high tensile strength or a high mechanical strength. The outer diameter of the resin tube is 0.12 - 0.165 in. and the thickness of it is 0.6-1.2 mm.

②Parallel connector without a detonator/explosive charge

Figure 5 is a schematic diagram showing the parallel connector of the non-electric "Pulkkot" firing system. The parallel connector separates and transmits Shockwaves coming ϊn from any direction. It links 3 or 7 rows or more of the shock tubes, so that the detonation of any one of the shock tubes fires the remaining 2 or 6 rows or all the other remaining shock tubes. It also fixes those shock tubes in their correct positions. This parallel connector comprises the resin box having a certain thickness and the linking portions to link the shock tubes together. A detonator or the explosive charge is not included inside the connector. Therefore the detonation way of the shock tubes using the parallel connector without the detonator/ explosive charge doesn't rely on the design of the Nonel connector that transmits the detonation energy from the priming explosive charge to the shock tube. The connectors developed so far have a detonator or the priming explosive charge in them, so the strict regulations for the handling of detonators should be obeyed when handling, maintaining and utilizing those connectors. The parallel connector without detonator provides high safety in the handling, maintenance and utilization of the connector.

"Pulkkot" shock tube connected to the parallel connector may be detonated both in a forward and reverse direction. The parallel connector in a linking state, when it is initiated, doesn't explode nor propagate Shockwaves, but burns.

The parallel connector connected with the shock tube of certain length provides delay with the high time accuracy (deviation is ± 0.5ms) up to 0.1 ms delay intervals within the range of from 0.2ms to 5ms. So it is the blasting means with the highest accuracy within the given range of time.

The parallel connector connected with the shock tube can provide the precise delay time which can not be obtained with any other blasting means, but the range of delay time is limited, so it can be now applied to the row-to-row each borehole delay blasting and to the instantaneous blasting as the high precision blasting component. ③MS delay socket Fig6 shows the principle of MS delay socket.

MS delay socket is the connection means between rows of the circuit or the earth surface that provides the delay of between 20ms-100ms. MS delay socket is the row-to row connector comprising a metallic tube casing in which the delay material and a small amount (20% by the common amount of priming explosive charge) of the priming explosive charge are packed and the shock tubes are connected to the both ends of the tube casing! MS delay socket is used when detonators with the same delay time are disposed in the blasting holes, and is not used when detonators with different delay times between the respective rows are disposed in the blasting holes.

MS delay socket transmits Shockwaves coming in from a forward direction by delaying the detonation for the delay time specified in the delay socket, and instantaneously transmits the Shockwaves coming in from a reverse direction. Time accuracy of the MS delay socket is over

95%.

④ shock Tube detonator

Fig 7 shows the principle of the shock tube detonator Tube detonator is the device to detonate a booster or the explosive charge disposed in a blasting borehole.

The tube body of the tube detonator is made of zinc, iron or aluminum and is 7.5mm in outer diameter. It corresponds to the detonator No 10 by the amount of the explosive charge. The blasting is instantaneous but according to the demand of the customer or the kind and scale of the blasting, the delay material with delay time of from 25ms to 500 ms may be placed in the tube detonator.

The instantaneous or delay detonators for detonation connected with the shock tube of a certain length (2-17m) detonate by shock waves (detonation spark) and the sealed ends of the connected shock tube afford a good water resistance.

In order to lower the detonation sensitivity in case the detonator remains in the misfired blast hole, the inventor inserts the rubber sleeve for protection around the priming explosive charge of the detonator so that the sensitivity of it is lowered by less than 1.5 times of the blasting sensitivity of TNT-hexogen fused detonating agent.

⑤Booster

The booster can be detonated by the shock tube detonator. The booster is the explosive having an ointment state and plasticity, which securely provides the detonation of explosive charges for the open-pit blasting in the humid holes or holes containing water.

The present invention has the following advantages. ① The connector with a detonator of the former Nonel system that has been used for 37 years up to now in the Nonel firing system developed in 1970s is newly replaced with a connector without a detonator/explosive charge and the disadvantage of unidirectional detonation of the Nonet shock tube is removed. The invention allows the detonation of the shock tube to be detonated both in a forward and a reverse direction and therefore provides a new firing system with the highest firing reliability.

②The parallel connector of the present invention has no detonator in it ,so that it's safe in blasting work and also in the maintenance and handling of the system components, and the cost of the firing system is lower than the Nonel system.

The following embodiments describe the non-electric "Pulkkof firing system and its use. These are for the purpose of the more detailed description and not of limitation.

Description of the drawings

Fig 1 shows the delay time of the open-pit bench hole-to-hole delay blasting and the multi-ringed circuit of the non-electric "Pulkkof parallel firing system. 1. "Pulkkof shock tube, 2. Connector without a detonator,

3. MS delay socket, 4. Detonator (disposed in the blast hole), 5. Booster (disposed in the blast hole). Fig 2 shows the delay time of the open-pit bench hole-to-hole delay blasting and the single circuit of the non-electric "Pulkkot" parallel firing system. Fig2 uses the same reference numeral for the same elements to

Fig 1.

Fig 3 shows the delay time of the V-cut open-pit bench hole-to-hole delay blasting and the single circuit of the non-electric "Pulkkof parallel firing system. Fig3 uses the same reference numeral for the same elements to fig1.

Fig 4 shows the circuit of non-electric "Pulkkot" parafiei firing system for use in the smoothing or regulated blasting.

1-"Pulkkot" shock tube, 2-connector without a detonator, 4-detonator (disposed in a blasting hole), 5-booster (arranged in a blasting hole), 6- explosive charge for the smoothing and regulated blasting.

Fig 5 is a schematic diagram showing the parallel connector of the non-electric "Pulkkof firing system. Fig 6 is a schematic diagram showing the MS delay socket of the non-electric "Pulkkot" firing system.

Fig 7 is a schematic diagram showing the shock tube detonator of the non-electric "Pulkkot" firing system.

1 -rubber sleeve for protection, 2-detonation explosive, 3-metal tube casing

Fig 8 shows the photographs of the open-pit bench hole-to-hole delay blasting using the non-electric "Pulkkot" firing system (on the left) and the open pit bench row-to-row delay blasting using the detonating fuse firing system (on the right). Embodiment: Open-pit bench hole-to-hole delay blasting using the non-electric "Pulkkot" firing system which generates no excessive explosive sound and no massive gas exhaustion.

The photographs (on the left) of the open-pit bench hole-to-hole delay blasting using the non-eiectric "Pulkkot" firing system and the photographs (on the right) of the open-pit bench row-to-row delay blasting using the detonating fuse firing system are presented in Fig 8.

The blasting components for the open-pit bench hole-to-hole delay blasting are the "Pulkkot" shock tube, the parallel connector, MS delay socket and the detonator which are the components of the non-electric "Pulkkot" firing system. The blasting circuit is shown in Fig 1.

First, one or more blasting boreholes are drilled according to the blasting situation and the blasting pattern. One row generally comprises 5-20 boreholes and these boreholes are adjacent to each other. 1 or 3 shock tube detonators or detonators of the booster are arranged at the bottom of the column of explosive charge in each borehole. Each shock tube embedded in the shock tube detonator is extended to the earth surface, on which it is linked to the parallel connector. The number of the parallel connectors within a row corresponds to the number of the blasting boreholes.

The parallel connectors connected with the shock tubes from each blasting borehole are linked with Pulkkot" shock tube for the circuit. MS delay sockets are connected between the rows as shown in Fig 1 to form the multi-ringed circuit.

When using the shock tube detonators with different delay times, only the parallel connector is used and MS delay socket is not used. The quantity of the explosive charge, the length of the filler and the position of the booster are the same as those used in the previous row-to-row delay blasting.

The blasting boreholes in a row detonate sequentially by the detonator placed in the column of the explosive charge.

In other words, the blasting boreholes in a row detonate sequentially with the delay time interval chosen in such a manner that when the incident stress fields generated by the detonation of the explosive charge in the 1^st blasting borehole propagate through its disruptive area and reach the disruptive area and explosive charge column of the 2^nd blasting borehole in the same row and then its reflective stress fields also overlap those areas, the second column detonates. The detonation in a row progresses sequentially with such delay time intervals and the detonation between rows progresses sequentially with the delay time intervals of 42ms or over 25ms.

As you can see in Fig 8, the hole-to-hole delay blasting using "Pulkkot" firing system generates no blasting gas exhaustion even though the rock of the top and the slope side of the bench is disrupted and blown off over 20 m (the left in Fig 8), but the open-pit bench row-to-row delay blasting using the detonating fuse firing system generates massive gas exhaustion even though the rock of the top and the slope side of the bench isn't blown off.

The technical and economical efficiency is shown In Fig 1.

Table 1: The technical and economical efficiency according to the blasting pattern.

Industrial applicability The non-electric "Pulkkot" firing system can be used in the hole-to-hole delay blasting method which significantly improves the disruptive quality by eliminating the energy loss due to the massive gas exhaustion and the excessive explosive sound. It can also be widely used in all kinds of blasting using this blasting method such as the underground mining blasting, the drifting blasting, the regulated and trimming blasting and the digging blasting.

Claims

Claims:

1. The non-electric "Pulkkot" parallel firing system is characterized in that it is the shock tube detonating system with the multi ringed circuit connected in parallel which detonates both in a forward and a reverse direction and it comprises "Pulkkot" shock tube, parallel connector without a detonator, shock tube detonator, MS delay socket and the booster. MS delay socket and the booster can be applied optionally according to the blasting situation.

2. The parallel connector according to the claim 1, to which 3 or more shock tubes can be linked, and generally 3 or 7 shock tubes favorable for the connection of the blasting circuit are connected with it.

3. The parallel connector according to the claim 1 and 2, characterized in that it contains no detonator or explosive charge.

4. The parallel connector according to the claims 2 and 3, characterized in that the detonation of any one of the shock tubes connected with the parallel connector detonates all the other remaining shock tubes, and all the shock tubes connected with the parallel connector can be either the input or the output.

5. MS delay socket according to the claim 1, characterized in that it comprises the metal tube casing, the delay material and the explosive charge, and the delay material and the explosive charge are packed in the metal tube casing.

6. MS delay socket according to the claim 1 , characterized in that it is the row-to row connector which delays when detonating in a forward direction in a circuit and which instantaneously detonates when detonating in a reverse direction.

7. The shock tube detonator according to the claim 1 , characterized in that it can be used in the instantaneous blasting and it can contain the delay material of up to 500 ms time delay and the rubber sleeve is inserted around the explosive charge to lower the blasting sensitivity.

8. The non-electric "Pulkkot" parellel firing system according to claim 1 , characterized in that the circuit has no delay in a row by the delay material.