Granite Blasting

The granite of the Canadian Shield fascinates me. This is the most primitive rock type formed by the cooling the planet's molten crust. These cross sections of granite show the diagonal seams of white, pink, grey, and black colour that is a feast for the eyes. The broad verticals, also shown on the surface, are the 'barrel' drill holes that enabled the granite to be blast apart.

Brent quarries provides a brief description of the blasting process:

Drilling and Blasting is done with large air operated or hydraulic drills that drill vertical holes of 3" to 6" in diameter and from 4' to 63' in depth. The holes are loaded with various types of explosives, detonators and time delayers then blasted to produce "Shot Rock" approximately 24" and smaller. The volume produced by each blast or "shot" is about 25,000 YD c¯ (cubic yards) depending on inventory requirements.

The close up picture (below) shows the half-tube which remains after the coordinated detonation of each barrel charge.

There are so many opportunites to shoot (what I consider) interesting photos of the surface of blast rock.

Missing from the Brent description is a very important element of the blast - the tire blanket that covers the blast surface. The tire blanket (shown below, looking like a sinister blob monster), is made up of hundreds of cut car tires bound by heavy metal wire. It prevents most, but not all, of the blast debris from showering the neighbouring area.

Granite blasting to widen the 400 highway occurring less than a mile from my mom's house would routinely send large rocks onto her driveway and into the forest. A neighbour had the top of a huge pine tree sliced off by a passing rock. That was fifty feet from his house. Nowhere is safe when they blast.

A close up of the tire blanket (below) makes for an interesting pattern and photo subject.