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ABSTRACT
The use of non-explosive demolition compounds has been extended within recent years to mining of building materials, as well as for the demolition of buildings and concrete structures in urban conditions. This environmentally friendly method has not been used in action for underground mining. The paper presents the outcomes of the research aimed at the elaboration of a new technology for underground mining of hard ores based on the use of demolition method as an alternative to the explosive one. A new compound of a non-explosive demolition agent, ensuring the pressure of 120-130 MPa on tunnel walls, has been devised. Technological properties of a new agent have been selected by taking into account specific conditions of their application in underground openings. Flow charts of mechanized mining of hard ores with the use of a non-explosive agent have been developed and tested.
Keywords: Non-explosion demolition agent, hard ore, underground mining
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INTRODUCTION
The non-explosive demolition compound is a powder chemical compound with expansion ability. It is non-flammable and is absolutely safe. Demolition compound solution is placed into a bore-hole; within a fixed duration the solution hardens, becomes expanded and produces pressure on bore-hole walls thus causing the demolition of rocks. Nowadays a non-explosive demolition material of various compositions and type are well known. This non-explosive demolition method is successfully employed in opencast mining of the deposits, as well as for demolition of buildings and concrete structure in urban conditions.
According to the data published by production companies, the pressure developed by various demolition materials ranges from 60 to 120 MPa (Bristar, Dexpan, CRACK.AG, Kayati, NRV-80 and etc.). Studies on the influence of demolition materials on the surrounding space have been conducted to establish rational technological parameters of demolition of concrete and various types of rocks [1,2].
This environment-friendly method of rock demolition remains unused in underground mining of deposits. It is natural that the method fails to compete with blast demolition. However it is now possible to identify a group of technological operations the implementation of which is justified both from economic and technical points of view with a non-explosive method, e.g. building of horizontal or ascending tunnels, widening of tunnels and shaping of their contours, breaking of small rock...