Verma, H.K. (2006) Delay precision in permitted copper delay detonators. Journal of Mines, Metals & Fuels, 54 (10&112). pp. 226-230. ISSN 0022-2755

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Blasting off-the-solid is the most commonly used method during development of galleries in bord and pillar method of underground coal mining. In this method, only P5 explosives are used with permitted delay detonators in accordance with the safety requirements stipulated by the regulatory bodies. Delay detonators made with pyrotechnic delay compositions have inherent scattering in their delay timings. It is desirable to use precise detonators to achieve better fragmentation, less vibration and noise. Overlapping of delay period is undesirable form production as well as safety point of view. In order to assess delay accuracy of permitted detonators of a domestic manufacturer, randomly selected fifty nos. of detonators from the same batch of detonators which was found suitable for use in underground coal miens in respect of their incendivity, handling and electrical safety, performance and water resistance characteristics were evaluated. Overlapping possibilities amongst delay periods were evaluated by calculating Winzer index and graphical methods. The findings reveal that significant scattering exist in all the delay periods. Scattering increases with higher delay periods. Overlapping possibilities between delay period 5 and 6 is found to be significantly high. Winzer index for the pair of delay period 5 and 6 is found to be very close to the threshold value for overlapping.

Item Type: Article
Subjects: Blasting
Depositing User: Dr. Satyendra Kumar Singh
Date Deposited: 20 Dec 2011 10:30
Last Modified: 20 Dec 2011 10:30

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