Four of Mawsons head office staff recently made a trip to the Pyramid Hill Quarry to view first hand a 'blast' into the granite shelf. The blast process can be very dramatic and our newer employees, Sandra and Tyler were suitably impressed.
Part of the trip included a tour of the quarry, highlighting our resident Peregrine Falcons nesting box.
Rock blasting is a fascinating part of our quarrying process - this information from Wikipedia gives a little insight into the use of explosives in the mining industry......
"The use of explosives in mining goes back to the year 1627, when gunpowder was first used in place of mechanical tools in the Hungarian (now Slovakian) town of Banská Štiavnica. The innovation spread quickly throughout Europe and the Americas.
Rock blasting currently utilizes many different varieties of explosives with different compositions and performance properties. Higher velocity explosives are used for relatively hard rock in order to shatter and break the rock, while low velocity explosives are used in soft rocks to generate more gas pressure and a greater heaving effect. The most commonly used explosives in mining today are ANFO based blends due to lower cost than dynamite.
In 1990, 2.1 million tonnes (2.32 million short tons) of commercial explosives were consumed in the USA, representing an estimated expenditure of 3.5 to 4 billion 1993 dollars on blasting. Australia had the highest explosives consumption that year at 500 million tonnes (551 million short tons), with Scandinavian countries another leader in rock blasting (Persson et al. 1994:1)."
Sandra, Tyler, Casey and Val wish to thank Alan for his hospitality at the Pyramid Hill Quarry. Another fascinating day on the job!