Environment Friendly Techniques Of Rock Breaking PDF Download

"The method of drilling and blasting with explosives is widely used in the mining industry for mine development and ore production. However, the use of explosives is associated with rigorous safety and environmental constraints as blasting creates toxic fumes, ground vibrations and dust. The following study is conducted on Soundless, Explosive-Free Chemical Demolition Agents (SCDAs), a more environmentally friendly method for the fragmentation of rock as a potential replacement of explosives. SCDAs are powdery materials similar to Portland cement, which when mixed as a slurry and poured into blind drilled holes, an expansive pressure is produced upon curing and eventually breaks the material apart. Given that SCDAs are commercially available, there is proof of workability in civil engineering applications for the breakage of concrete foundations. SCDAs are commonly used in the demolition of concrete foundations as well as in stone quarries where the use of explosives is either restricted or prohibited. An interest is drawn towards SCDAs due to its environmental advantages which mitigate the risk of explosives. This study is a step in investigating its workability in hard rock mine development and production where the rock is subjected to high in-situ confinement pressure which would make rock breakage cumbersome. A drawback of the SCDAs is that the time needed to develop the full expansive pressure is too long for practical mine development applications. The primary goal of the study is to accelerate the expansion rate of SCDAs as one of the steps towards development of a feasible method of rock breakage in underground mines. The SCDA used in this investigation is Betonamit, a commercially available expansive cement. The experimental investigation was conducted in the Rockbolting Lab of the Mine Design Laboratory. This study is an extension of the work previously conducted by Musunnuri & Mitri (2009) and Dessouki & Mitri (2011) in the Mine Design Laboratory of McGill University.The factors investigated are: the expansive pressure, expansive pressure rate, and fractural growth on concrete blocks. The effect of chemical additives on expansive pressure is investigated with the goal to reduce the time of expansion. Common concrete accelerators including calcium chloride, sodium chloride, calcium formate, and sodium were investigated." --