Field Investigation in the Detonation Behavior of Emulsion Explosive Column Induced With Air Gaps

Abstract

In blasting of soft to medium hard rock, the problem of high density resulting in excessive utilization of emulsion explosive is well known. The authors have conducted some experimental blasts to delve into the detonation behavior of conventional blasting and various other explosive consumption reduction techniques which induce air gaps using plastic tubes, plastic bottles or plastic balls in the explosive column. Resistance wire technique is used for gauging in-hole continuous velocity of detonation. The VOD varies from 5321.6 m/s to 4544.2 m/s and from 5123.4 m/s to 4274.2 m/s in conventional site mixed emulsion column and distributed spherical air gap column respectively. The detonation behavior is stable and similar in both these cases. While using plastic bottles or plastic tubes as air gaps, the VOD is fluctuating from 4636.3 m/s to 3268.4 m/s and from 4935.9 m/s to 3362.8 m/s respectively with a collapse of about 12 % from the average VOD of conventional SME column. The VOD falls abruptly when the detonation wave encounters large air gaps but it is successfully travelling through the air gaps making the detonation behavior more capricious.

Emulsion Explosives: A Tutorial Review and Highlight of Recent Progress

“…An interesting approach to optimising the performance of EEs in softer rocks is to employ air gaps within the explosive column loaded into the boreholes. It has been shown that with careful choice of the dimensions and distribution of such air gaps, the velocity of detonation is only slightly reduced, while allowing a noticeable reduction in the amount of EE loaded into the borehole [ 39 ]. That said, no information was presented as to whether the amount of mechanical work (i.e., volume of rock mined and the degree of fragmentation in the mined rock) has been adversely affected by the introduction of those air gaps and, if so, what the magnitude of the decline of the performance is.…”

“…Among those, the emission of carbon monoxide and nitrogen oxides is seen as problematic, particularly in the case of underground blasting operations, due to the toxicity of those gases. The composition of post-detonation gases is a function of both the composition of the EE (as the oxidising agent to fuel ratio influences the carbon monoxide to carbon dioxide and nitrogen to nitrogen oxides ratios) as well as external circumstances (as cracks in the walls of the borehole or the presence of water within can lead to the occurrence of incomplete detonation) [ 39 ].…”

Factors Affecting the Detonation Velocity of an Explosive Charge

“…Соот ветственно, в отсутствие привязки параметров БВР к на турным измерениям СД качество подготовки горной мас сы к выемке может быть значительно хуже относительно БВР с предварительным производством измерений СД [8]. Проведенные исследования подтверждают расхождение номинальных (указанных заводом изготовителем) значе ний СД со значениями, полученными инструментальны ми методами в полевых условиях [9,10,11]. На рис.…”

Implementation and Verification of Effectiveness of Bulk Emulsion Explosive with Improved Energetic Parameters in an Underground Mine Environment

“…It should, however, be noted that, apart from a number of manufacturing parameters which influence the working capacity [6,7], the results of blasting are affected by many different technological parameters. They are only observed in real mining conditions and cannot be evaluated under laboratory conditions [8,9]. The most important factors from the adopted technology point of view are the diameter of the blastholes, method of initiation or time between charging of explosives, and firing.…”