Abstract

STEENKAMP, N.C.. Open-pit post-blast dust cloud lightning. J. S. Afr. Inst. Min. Metall. [online]. 2024, vol.124, n.4, pp.209-212. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2071/2024.

Lightning has been observed in dust clouds following open-pit blasting. It is proposed that the occurrence of this phenomenon is related to the physical composition and characterization of the mineral fines that comprise the bulk of the dust cloud. Silicate minerals, which are susceptible to fine fracturing during blasting, generate the initial charge. This is further enhanced by collisions and friction during the turbulent upcast in the post-blast dust cloud. Varying size fractions result in different rates at which these particles drop out of suspension and create a secondary temperature gradient. This results in the creation of two charged zones and increases the potential of developing a discharge in the form of lightning. The ideal prevailing meteorological conditions need to be windless to minimize the effect of particle dissipation and have sufficient moisture to enhance the potential of generating lightning.

Keywords : open pit; blast; dust; cloud; lightning.

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