From The Supply Post Archives: What A Blast!

Jul 8, 2021 - 4 years ago

Pitt River Quarries Ltd., a wholly owned subsidiary of Columbia Bitulithic Ltd., operates this granite quarry in the Pot Polder area of Pitt Meadows, B.C., on the outskirts of Vancouver.

From The Supply Post Archives - What A Blast!

Shown here is the primary means of reducing the extremely hard granite to a size which can then be handled by conventional jaw and cone crushers. This blast in July took 21 metric tonnes of explosives, loaded into 386 holes each 38 feet in depth, to fragment well in excess of 50,000 metric tonnes of rock.

As can be seen in the picture, each hole is triggered in sequence, starting in the centre of the exposed face and progressing over the next 1.1 seconds to the back corners of the drilled area. Quarry Superintendent Tom Sidney explains that this method not only produces a well fragmented product small enough to be fed to the Baxter 40” x 50” Primary jaw crusher, but also leaves the material in a clean pile that can easily be handled by the 988 Cat loader used to feed the crusher.

Pitt River Quarries blasts rock here several times a year to keep up with the demand for their aggregates. This blast was a bit larger than normal and could be accommodated, as it coincided with a move of crushing and related equipment to a lower bench on the site.

The quarry was first opened up in the late 1940’s to produce rock to rebuild the dykes following the Fraser River floods of 1948. Since that time, and up until it was purchased by Columbia Bitulithic, most of the rock taken out has been used for that same purpose on dykes and breakwaters around local coastal waters. It is also a favourite haunt of local stonemasons and other landscape architects looking for one of the several shades of unique decorative granite rock found in the quarry.

Most of the rock today is used by Columbia Bitulithic for making a high grade asphalt for use on various paving contracts around the lower mainland. The extreme hardness of the rock improves the wear quality of the final product which makes for longer lasting road surfaces. The crushing plant itself is fairly flexible, allowing for production of several specially sized aggregates for various unique orders obtained in recent years.

Shipping of the majority of the rock is by barge through the on-site loading facilities on the Pitt River, for transportation to various Columbia Bitulithic’s depots in the area. Smaller shipments are handled in the more common method of truck, or truck & trailer.

At the present rate of use, the reserves in this quarry will be fulfilling the needs of roadbuilders and stonemasons well into the next century.

This article first appeared in Supply Post, September 1993.