Reactivity of Pyrite-Bearing Ores with Ammonium Nitrate Based Explosives: Risk Control
Sulfide ores, particularly those containing pyrites subject to weathering process, can react with explosives under certain conditions, generating a highly exothermic autocatalyzed chemical reaction. This phenomenon can have effects ranging from toxic gas emanations to premature detonation of the explosive charge.The phenomenon occurs due to a reaction of the ammonium nitrate present in the explosive, with the hydrated ferrous sulfate generated as a result of the natural weathering of the pyrite. This kind of orebodys are mentioned in the mining industry as reactive ground.Countless such cases have been described in technical literature. From gold underground mines in Canada to hot rock iron mines in Hamersley Province, Western Australia, and copper mines such as Chuquicamata in Chile.Enaex S. A. was in charge of investigating a serious incident of premature detonation and deflagration which occurred in Chuquicamata in December 1988. On that occasion, the procedure recommended by the U. S. Bureau of Mines was adopted, the phenomenon occurred in the mine was reproduced to laboratory scale①, the risk conditions causing the incident were determined, and recommendations were given in order to minimize the probability of future occurrences.This paper presents a set of recommendations to reduce risks, based on actual experience and laboratory tests. Several cases have been analyzed in the last few years, including premature non controlled deflagration and a spontanepus detonation of a 5-month-old misfired explosive charge.The USBM procedure was lighttly modified, to adapt it to local conditions and new instrumentation, and was established as Enaexs rule to investigate possible reactivity situations in pyrite-bearing rocks or, in general, potentially reactive rocks.
pyrite reactive ground explosives ammonium nitrate
Carlos P. Orlandi
Technical Development Manager, Enaex S. A., Santiago, Chile
国际会议
The Asian-Pacific Symposium on Blasting Techniques(亚洲太平洋地区爆破技术研讨会)
昆明
英文
351-356
2007-05-08（万方平台首次上网日期，不代表论文的发表时间）