산업안전지도사 2차 기출풀이 | 제16회 8번 - 발파 불발 시 원인·대책 (발파 표준안전작업지침 제34조·별표3)

📝 Solutions to Past Questions from the 16th Industrial Safety Instructor 2nd Round Exam Q. Answer the following questions regarding cases where unexploded explosives occur after blasting operations, in accordance with the Standard Safety Work Guidelines for Blasting. 1) In electric blasting, list three causes and three countermeasures for the case where only one detonator out of the total detonators is ignited. 2) In non-electric blasting, list two causes and one countermeasure for the case where a signal tube is damaged and the blast fails. 3) In electromagnetic blasting, list three causes for the case where the blasting circuit fails sporadically. ━━━━━━━━━━━━━━━━━━━━━━ ⏱️ Timeline 00:00 Intro 00:25 Problem Presentation 01:08 [8-1] Detonation of only one electric blast (Sub-question Intro) 01:29 [8-1] 3 Causes (Wire stripping/breakage / Detonator wire detachment / Individual wire damage) 02:00 [8-1] 3 Countermeasures (Prevention of individual wire damage / Inspection of blasting mainline before connection / Measurement/repair of blasting mainline with a resistance meter) 02:46 [8-2] Damage to non-electric blasting signal tube (Sub-question Intro) 03:05 [8-2] 2 Causes (Delayed blasting bunch connector fragments / Bench blasting fragment damage) 03:31 [8-2] 1 Countermeasure (Maintaining parallel distance + Preventing scattering of cloth/vinyl) 03:50 [8-3] Sporadic Electro-blasting Failures (Sub-question Intro) 04:07 [8-3] 3 Causes (Exceeding Standard Capacity / Mixing with Detonators from Other Companies / Stripped/Broken Wires) 04:40 Legal Basis 05:23 Key Summary 06:15 Expected Questions 07:06 Wrap-up ━━━━━━━━━━━━━━━━━━━━━ 📌 Answer Summary [8-1) Electric Blasting — Only 1 Detonator Out of Total Detonators] 〈3 Causes〉 ① Stripped or broken wires in the connection section ② Disconnection of wires from a failed detonator ③ Damage to individual wires during charging of the detonator 〈3 Countermeasures〉 (Original text in the Countermeasures column of Appendix 3) ④ Ensure that individual wires are not damaged during charging of the detonator. ⑤ Check for any broken or damaged wires on the main wire before connecting the main wire to the detonator circuit. ⑥ Measure both ends of the blasting busbar with a resistance meter to verify that the specified resistance is present. If infinite resistance is not observed when the busbar is disconnected, investigate the cause of the defect, such as damage, insulation failure, or breakage, and repair the busbar before use. [8-2) Non-electric Blasting — Signal Tube Damage] 〈2 Causes〉 ① Signal tube damage caused by fragments from a bunch connector that detonated first during horizontal or delayed blasting. ② Signal tube of a non-electric detonator being severed or damaged by fragments during bench blasting. 〈1 Countermeasure〉 ③ Maintain a sufficient parallel distance between the bunch connector/surface-connected detonator and the signal tube, and take measures to prevent fragments from scattering by covering them with cloth or vinyl. [8-3) Electronic Blasting — Sporadic Blasting Circuit Misfires] 〈3 Causes〉 ① When blasting exceeds the specified capacity of the blaster. ② When mixing with detonators from other companies. ③ Stripping or disconnection of the connection points. ※ Selected as 3 representative items out of 4 items in the original text of Appendix 3 (Electronic Blasting). 📖 Basis: Article 34 (Measures for Misfires) of the Standard Safety Work Guidelines for Blasting and [Appendix 3] Causes and Countermeasures for Misfires Related: Ministry of Employment and Labor Notice No. 2023-34 (Effective July 1, 2023) ━━━━━━━━━━━━━━━━━━━━━━ 🔮 Related Expected Questions • [High Likelihood of Question] Article 34 of the Standard Safety Work Guidelines for Blasting: General Handling Procedures for Unexploded/Unexploded - Waiting time before verification and handling procedures by type of blasting (electric, fuse, detonating cord, non-electric/electronic) • [High Likelihood of Question] Safety distance and access restriction time (5 minutes for electric blasting, 15 minutes for fuse blasting, etc.) during unexploded hole handling, and prohibition of re-drilling in locations adjacent to unexploded holes • [Medium Likelihood of Question] Safety measures before blasting and ignition - Deployment of lookouts, establishment of evacuation and access restriction zones, blasting signal (warning, ignition, release) system • [Medium Likelihood of Question] Compliance requirements during charging, stemming, and wiring - Filling with stemming material, organizing individual wires, wiring insulation, etc. 📢 Jeong's Safety Classroom Past Exam Question Solutions Series for the Industrial Safety Instructor 2nd Round Exam Tags: Industrial Safety Instructor, Past Exam Questions, Blasting Operation, Standard Safety Work Guidelines for Blasting, Unexploded, Electric Blasting, Non-Electric Blasting, Electronic Blasting, 2nd Round Exam, 16th Round #Indus...