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Fletchers Lake and Kinsac Quarries
Two historical quarries in the Fall River area of Halifax used “plug and feathers” to extract building stone.
The Fletchers Lake Quarry is shown on a 1909 geological map but there are no production records for it and little is known about the operation. It was on the west side of the lake, dug into a rock bluff. Quarrying took place along the natural cliff face over a distance of 50 metres.
The Kinsac Lake Quarry was about three kilometres west of the Fletchers Lake Quarry. Like the Fletchers Lake operation, its production history is not known but the Kinsac Lake Quarry also appears on the 1909 map, so we know both quarries started prior to that year.
Two openings were made in the outcrop on the eastern shoreline of Kinsac Lake. The northerly opening was ten metres long and dug seven metres into the rock bluff. The second opening was immediately south, a notch about five metres long by five metres wide cut into the outcrop.
“Plug and feathers” is an old way of extracting stone that leaves it in solid, undamaged blocks, perfect for building.
Historical quarries like those at Fletchers Lake and Kinsac Lake drilled holes into the rock face in a straight line. Feathers (metal wedges) were placed in the holes and plugs (long metal pins) were hammered into the holes. As the plugs were forced down by the hammering, they pushed the feathers outward. This put pressure on the rock and caused blocks to break off in a straight line without damaging the stone.
In quarries that provide rock like gypsum for use in wallboard, or aggregate for use in construction, we blast the rock because that is the most efficient way to break it off the quarry’s working face. The rock is then crushed as part of preparing it for manufacturing or construction, so it does not matter that we break the rock in blasting.
Blasting also causes microfractures throughout the rock for some distance from the blast, so it affects not just the specific stone being removed, but also surrounding stone.
That is why blasting is not used to extract building (aka dimension) stone. We need those big, solid blocks to make big, solid buildings!