| 摘要 |
An electric firing mechanism with a 0.5 s time lag, comprising a firing unit in the form of a firing head that is durably connected with shot-firing cables, and a blasting-cap unit with a metal case with a blasting explosive and an initiating agent and a metal sleeve in it that contains a retarding mixture comprising potassium permanganate and antimony, the latter functioning as the reducer and having grain size in the range from 15 to 50 micrometers and the grain surface area in the range from 100 to 600 m<2>/kg, wherein the retarding mixture contains a ferrosilicon additive in the amount of 0.5 to 1.5% by weight of the mixture.
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