The limestone industry has long been active in the Thames River Valley.
Early on, to loosen the rock, blasting was done with black powder and a light-and-run method. Black powder was replaced with rack-a-rock, which was a form of mining explosive patented in the 1870s. Rack-a-rock consisted of an oxidizing agent (potassium chlorate) and a combustible liquid (nitrobenzene) that were combined at the job site. It arrived as sticks packed into a small box. Each stick was about a foot long and was wrapped in cotton. A fuse and cap would be attached.

One historian wrote that:
“The men treated these potent firecrackers with the utmost nonchalance. One man made a practice of clamping on the nitroglycerine caps with his teeth, and another broke the sticks over his knee when only a half cartridge was required.”
Today, blasting is taken on with much more care and precision.
Watch as a blast takes place in a contemporary quarry pit.

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