AU2021103394A4 - Electronic Trunk Line Delay for Explosives - Google Patents

Abstract

A system for initiating blasting comprising a bus wire connected to an electronic blast machine and extending to a series of electronic trunkline delay detonators on the surface, each detonator located outside of a blast hole and used with an existing non-electric and detonating cord downline system inside the blast hole. 5/6 Electronic Trunk Line Delay Brief description of the drawings Figure 1 presents the basic diagram for the method Fi Figure 1.

Description

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Electronic Trunk Line Delay

Brief description of the drawings Figure 1 presents the basic diagram for the method

Fi

Figure 1.

Electronic Trunk Line Delay

An improved more accurate safer reliable blasting initiation system.

Field of the invention

The present invention relates to a method of initiating of a blasting system using a combination of standard non-electric detonators and electronic detonators. The method allows for the high precision timing of electronic detonators and the robustness of non-electric detonators.

This invention combines the use of two detonators, which use different methods of ignition, to improve the initiation and accuracy of every single blast hole during blasting operations.

Definitions

Electronic Trunk Line Delay (E-TLD): Refers to the authors invention of a programmable electronic surface delay detonator.

Non-Electric Trunkline Surface Delay: Standard shock tube type non-electric surface delays used for interconnecting of blast holes in a blast.

Electronic detonator: Programmable Electronic detonator used for down hole initiation of an explosive column.

Non-electric detonator: Down hole detonator or trunkline delay detonator initiated via shock tube.

Trunk line: Main Surface firing line. (Generally referred to with Detonating Cord or electricfiring line)

Bus Wire: Main electric firing line connected to individual electronic detonators.

Scatter: Varying inaccurate timing delay.

Detonator wire lead: Electric wire (normally plastic insulated copper or copper coated steel) attached to the detonator and available with varying lengths.

Detonator tube lead: Plastic shock tube attached to the detonatorfilled with initiating powder used to initiate the detonator and available with varying lengths.

Blast Pattern: Distance between holes and rows of holes in a blast.

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Electronic Trunk Line Delay

Background of the invention

The recent introduction and use of electronic down hole detonators in blasting is well known. It is also known that sometimes due to rock properties, detonators sequence of ignition, etc. they fail to initiate. In most of these cases the shock wave produced by neighbouring blastholes collapse the electronic detonator casing, where the electronic circuit is located, which ultimately causes a failure in the detonator.

It is also well known non-electric detonators, which use non-electric downhole detonators in conjunction with non-electric trunkline surface delays and use a non-electric signal for its ignition, is a robust system used to initiate blasting and tends to be more reliable. Non-electric downhole detonators are also used in conjunction with detonating cord and non-electric cord delays but still however, lack the accuracy in timing of electronic detonators and do not provide the same control and checking ability as the electronic system.

In some blasting operations, companies wanting to take advantage of the accuracy of electronic detonators, and to prevent a possible misfire of blast holes, add an additional detonator to the blast hole - this detonator is of the non-electric type, so if the electronic detonator fails to detonate, the non-electric detonator will detonate the charge. The blasthole may detonate out of time or sequence, but operators prefer this result instead of having to deal with a misfire.

Another issue of concern with the use of electronic detonators is, recovery of the detonator if it fails to log at the time of loading. As logging is usually performed after the blast hole is loaded and stemmed, the faulty detonator cannot be removed prior to firing and the blast hole usually fails. The use of an 'Electronic Trunkline Surface Delay' allows for easy removal and replacement of a faulty detonator prior to the firing of the blast as it is located on the surface.

The role of the introduction of the 'Electronic Trunkline Surface Delay' is to increase accuracy and to eliminate or reduce scatter in delay timing when used in conjunction with an instant or a delay down hole non- electric detonator.

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Electronic Trunk Line Delay

Summary of the Invention

Current Technical problems:

Shrink wrapping: Shrink wrapping of electronic detonators can occur when blast holes are to close in proximity to each other. Electronic detonators can be adversely effected by shock waves from other blast holes during the blasting process. This produces a failure of the detonators which is called shrink wrapping.

Low accuracy of non-electric detonators: Due to manufacturing processes, accuracy of timing of non-electric detonators is limited and cannot be further improved. This produces an undesirable dispersion of timing for the detonators that should have identical initiation times or sequences.

Electronic Detonator Logging Failure: As logging is usually performed after the blast hole is loaded and stemmed, if a faulty electronic detonator is detected, it cannot be removed prior to firing and the blast hole usually fails.

Waste produced: The use of two different types of technologies requires the use of two different methods for transmitting an initiation signal. The transmission is conducted through either a non electric shock tube or electric wires. Both these technologies produce waste materials once the blasting is finalised. Both the electric wire and shock tube that is not consumed in the main blast becomes waste material.

Limited packaging quantities: Current Non-electric Trunkline Surface Delay detonators are supplied in varying lengths from a nominal 3.Omts upwards to provide for interconnecting of blast holes. Each case of detonators is limited to a single nominated length for all leads in each case. (e.g. 6.0 mts x 120 units per case) The number of these detonators packed in each case is based on the length of the detonator tube lead which will affects case size, weight etc. As leads become longer the quantity per case is reduced which increases freight, storage & handling costs.

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Electronic Trunk Line Delay

Solution to technical problems Shrink wrapping:

The first aspect of the invention is the use of an electronic detonator and a traditional non-electric detonator. The traditional non-electric detonator is used in the blast hole and the electronic detonator is now used outside of the blast hole on the surface to prevent current 'Shrink wrapping' issues.

Low accuracy of non-electric detonators:

The second aspect of this invention relates to a method of initiation where two detonators are used as with standard non-electric blasting systems currently in uses, but it improves timing accuracy over current systems. The nonelectric detonator, with a selected instantaneous, or delay time as used in standard blasting techniques, is placed into the blast hole as is traditionally done. The end of the non-electric shock tube at the top of the blasthole is connected to a 'Programmable electronic trunkline surface delay detonator' (E-TLD the invention) with variable programing delay times.

Electronic Detonator Logging Failure:

The third aspect of this invention relates to the use of an 'Electronic Trunkline Surface Delay' with a traditional non-electric detonator or detonating cord, which allows for the easy removal and replacement of a faulty electronic detonator prior to the firing of the blast, as it is situated on the surface of the blast.

Waste produced:

The fourth aspect of this invention is the use of the reduced length E-TLD, this allows for a reduction of shock tube waste associated with the use of non-electric shock tube type trunkline delay detonators. Due to the shorter lead lengths required for the E-TLD, an increase in the number of units can be packed in cases and additional waste can be reduced on packing materials.

Costs:

The fifth aspect of this invention is, as the E-TLD (the invention) replaces the non-electric (Shock tube type) trunkline delay, a large reduction in costs can be achieved. The present invention eliminates the requirement for multiple varying trunkline delays as currently exists, and provides for a single line item. As all E-TLD units are identical and programmed at the blast site, substantial costs can be reduced on packaging, manufacturing, storage, inventory, transport and handling costs.

Flexibility:

The sixth aspect of this invention is the E-TLD detonator is programmed and connected via surface bus wires, tested and fired with standard existing electronic systems. A combination of signal transmissions (Electric and Non-electric) is used with the blast instigated by an electronic firing system. This invention allows for ongoing use of current firing systems and manufacturing processes and requires only minimal changes in manufacturing processes in the manufacture of the Electronic Trunkline Surface Delay Detonator - E-TLD "The Invention".

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Electronic Trunk Line Delay

Invention Additional Details: Blast hole timing will have an ignition time dependant on the time programmed for the electronic trunkline delay detonator, (E-TLD) which is located on the surface at the top of the blast hole. This will prevent shrink wrapping in the electronic detonator as it is now located outside of the blast hole.

If zero (Oms) delay timing is used for the non-electric down hole detonator, the detonator will detonate as per the accuracy of programmed electronic trunkline delay detonator timing.

E-TLD - Electronic trunkline delay detonators will not require packaging in individual delay packages as with the Non-electric type as programming of delays for E-TLD's occurs at time of loading at the blast site.

Claims (5)

1. Electronic Trunk Line Delay

   Claims: 1. A method to initiate blasting wherein an electronic trunkline delay detonator located outside of the blast hole can be used with existing non-electric and detonating cord downline systems inside a blast hole to improve accuracy and safer more reliable blasting.
2. 2. A method to initiate blasting according to claim 1, where the electronic trunkline delay detonators can be used with non-electric LP and MS Delay downhole products to improve timing accuracy.
3. 3. A method to initiate blasting according to claim 1, where the electronic trunkline delay detonators are located on the surface providing for easy removal and replacement if faulty detonators are detected, and providing for safer blasting and reduction in misfires.
4. 4. A method to initiate blasting according to claim 1, where the electronic trunkline delay detonators are able to be used with current existing electronic programming and firing systems eliminating new system entry costs.
5. 5. A method to initiate blasting according to claim 1, where the electronic trunkline delay detonators are not required to be packed in individual delay and detonator lead wire length cases, as with current non-electric surface delay detonators, thereby substantially reducing inventory, packaging, transport and storage costs.

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