Lab Session #1 Initiation Systems and Types of Explosives

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2 Lab Session #1 Initiation Systems and Types of Explosives The main goal of this laboratory session is to provide a practical experience in the use of different type of explosives and initiations systems. The students will measure different parameters and will submit a written report within in seven days from the day of the lab session (view preparation of reports section). All these measurements will be previously estimated by several theoretical methods. The type of explosives and initiation systems are specified in the list below: Initiation Systems: Safety Fuse Nonel Shock Tube Electric Detonator Electronic Detonator Type of Explosives: Dynamites: Unimax/Unigel Permissible Emulsion Charge Pre-split Emulsion Charge Emulsion Explosives Blasting Agent: ANFO (Booster Required) Shaped Charge Seven different shots will be done during the lab session in order to show the performance of each explosive and initiation system. The description of each shot is indicated below: SHOT #1: Safety Fuse Brief introductory explanation to safety fuse. A 1 foot long safety fuse is initiated by a pull-wire initiator. The burning rate is measured. Figure 1. Pull-wire initiator (left) and safety fuse (right) - 1 -

3 SHOT #2: Hand Charge Brief introductory explanation to hand charge and fuse detonator. Two 37 inches long safety fuses are initiated by two pull-wires initiators. Two fuse detonators are crimped to both safety fuses and inserted within the main charge. The charge is thrown from the ERL Station no.2. SHOT #3: Shock Tube Figure 2. Hand Charge Brief introductory explanation to shock tube. A 300 feet long shock tube is initiated by a shotgun primer. The shock tube is held by the students so they can actually feel the shock wave traveling throughout the tube. Figure 3. Nonel Shock Tube line (left) and cross view (right) - 2 -

4 SHOT #4 Series Detonation Brief introductory explanation to electric detonators and the series configuration. 3 charges in series with electric detonators. Figure 4. Electric detonator parts (left) and series configuration (right) SHOT #5 Parallel Detonation Brief introductory explanation to parallel configuration. 3 charges in parallel with electric detonators. The total electrical resistance is defined by: Figure 5. Parallel configuration - 3 -

5 SHOT #6 Types of Explosives Six different charges will be initiated by non-electric detonators with a 3 second delay between each of them. Each nonel detonator will be initiated by shock tube. The last one will be a shaped charge pointing at the ground. A steel plate is placed between the charge and the ground and it will perforated by the jet. The students will measure hole diameter and jet depth. Figure 6. Typical non-electric detonator construction Figure 7. Explosive charges distribution - 4 -

6 SHOT #7 Electronic detonators Brief introductory explanation to electronic detonators and developing hands on practice using 3 detonators using of Orica I-Kon system. Figure 8. Electronic detonator parts Configuration and Firing Steps 1. Turn on logger 2. Clip detonator to harness wires 3. Enter delay and confirm choice 4. Add up to 200 detonators 5. Turn off logger 6. Attach harness to logger and use banana plugs to attach blaster 7. Turn on blaster 8. Insert key 9. Follow the blasting instructions on screen 10. Fire using two hands - 5 -

7 List of Materials: Concept Quantity Safety Fuse 5 m Shock Tube 10 m Electric detonator 6 Detonating cord 20 m Nonel detonator 6 Orica I-Kon System - Unimax/Unigel 1 stick Permissible Explosives 1 stick Pre-split charge 1 stick Emulsion Explosives 1 stick ANFO 2 lb Shaped Charge 1 Metal steel plate 1 Shotgun primers 2 Pull-wire initiators 7 Paper tube for standoff distance 1 Tape measure 6 Stopwatch 6 Estimated time distribution Time Action 1:00 pm Arrival and PPE 1:30 pm Shot #1 1:50 pm Shot #2 2:10 pm Shot #3 2:30 pm Shot #4 3:00 pm Shot #5 3:30 pm Shot #6 4:00 pm Shot #7-6 -

8 Preparation of reports The reports will be submitted as groups. It is important that a report maintains the interest of the reader while transmitting all essential information as concisely as possible. Each report should be written to suit the particular exercise under study. Do not present in the report sections that are simply a re-write from manuals or text books. Do not include any of the printed sheets from the laboratory manual in the main text of your report, unless this is a table or a question sheet that you have to fill in. The structure of the report should include: 1. Report Title: Use a title page and include on this your name, group and date of experiment. 2. Table of contents 3. Introduction: This should be brief and should include a short statement of the objectives of the experiment. Basic physical principles should be outlined. 4. Description of Apparatus: A short description of equipment used. 5. Procedure: This section should only briefly outline the procedure with emphasis on the more important steps in the exercise. Draw attention to any part of the procedure, noting any difficulties encountered and how these were overcome. 6. Results: All measurements and derived results should be included in a suitably devised tabular form. Wherever appropriate, include a graph as this always aids in the presentation of the results. 7. Analysis of Results: This is the most important section of the report and hence should be given the most weight during writing. The students must predict the values using different theoretical equations. These values will be later validated using the results recorder during the lab session. Finally, the students must calculate the error between the analytical predictions and the experimental measurements, comment on the sources of error in the experiment and their effects on the results. 8. Conclusions: This section should contain a discussion of the results, including a critical evaluation of the experiment, the equipment used, and the techniques employed. 9. Bibliography: All publications referred to in the report should be listed with full details of author, title, publisher and year of publication. Clearly indicate in the text all references to these authors or reports

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10 Lab Session #1- Work Sheet Initiation Systems and Types of Explosives Name: Date: 1. Safety Fuse Length (cm) Time (s) Burning Rate (cm/s) Misfire Yes No 2. Hand Charge Hand Charge Components Safety Fuse #1 Length (inch) Safety Fuse #2 Length (inch) Misfire Yes No 3. Electric Initiation system Electric Initiation System SERIES PARALLEL Detonator number # Number of detonators Electric detonator resistance (Ω) Detonator delay (msec) Legwire length (cm) Lead wire length (cm) Total measured resistance (Ω) - 9 -

11 4.Shaped Charge Diameter (cm) Standoff (cm) Hole Diameter (cm) Hole Depth (cm) 5.Electronic detonators Delay #1 (ms) Delay #2 (ms) Delay #3 (ms) Pass/Fail Test Blaster Signature PASS FAIL Questions & Calculations Hand Charge: a. Why do we use two safety fuses? b. How many detonators are placed inside the charge? 2. Electric Initiation System: a. Calculate the total resistance of the series circuit. b. Calculate the total resistance of the parallel circuit. c. What is the voltage required?

12 d. How many detonators can the fireset initiate at the same time? e. What is the correct ion factor check? 3. Shock tube initiation system for surface mining: V-Cut Method Trench Line Method Surface Delay: 25 ms Down Hole Delay: 500 ms a. Calculate the delay for the section 4 in the V-cut diagram

13 b. Calculate the total time for the whole blast in the V-cut diagram. c. Calculate the delay for the section 4 in the trench line diagram. d. Calculate the total time for the whole blast in the trench line diagram. e. Which one do you think is a better design? Why? 4. Shock tube initiation system for underground mining: Horseshoe Method Detonator Delay: 500 ms

14 a. Calculate the delay for the section 14 in the horseshoe diagram. b. How long it will take to detonate the full face? 5. Type of Explosives: Explosive Components VOD (m/s) Dynamite Permissible Explosives Pre-slit Explosives Emulsions Explosives ANFO Shaped Charge a. In the table above, which ones are molecular explosives? b. In the table above, which ones are tertiary explosives?

15 c. What are permissible explosives? d. What is the difference between pre-split explosives and emulsions explosives? e. What is the optimum standoff distance when using a shaped charge? 6. Electronic Initiation System: a. What type of connection (series/parallel) is used in electronic detonators? b. What is the main difference between electric and electronic initiation systems? c. What is the main current disadvantage of the electronic initiation system? d. How many detonators are we able to initiate at the same time using one Orica I- Kon System? e. How many hands do we need in order to fire the Orica I-Kon System?