Tatlock Quarry

Tatlock Quarry Mine, Ontario Canada

  • Type: Man Made Structure
  • Diameter: 850 X 529 metres
  • Formed 1.255 Billion years
  • Location: South of Algonquin Park, Ontario, Canada N 45° 05.8’ W 76° 29.7’
  • Calcium carbonate mine* in the Grenville Province

*Calcium carbonate, or CaCO3, comprises more than 4% of the earth’s crust and is found throughout the world. Its most common natural forms are chalk, limestone, and marble, produced by the sedimentation of the shells of small fossilized snails, shellfish, and coral over millions of years.

Aerial view of the Tatlock Quarry from my bird GOZooM.

Tatlock Quarry is the largest calcium carbonate mine in Canada and is said to produce the purest calcium carbonate in the world. The marble is white, medium crystalline calcite.  A number of north trending calcite zones with varying silica content are present on the property. The silica content of the main quarry belt is less that 3.0%. Minor amounts of amphilbolite, phlogopite and diopside are noted. The marble dips approximately 55° east and the low silica zone has a true thickness of 85 metres. The low silica zone is bounded on the east by calcite that has a silica content ranging from 3.0 to 11% and on the west by dolomite. (Kelly, 1996)

OMYA mines and crushes the calcium carbonate at the Tatlock quarry and processes the product at its plant west of Perth Ontario along Highway 7.

The high calcium crystalline limestone is thought to be approximately 1.255 Billion years old. Broken shell material was deposited in warm shallow seas and then subjected to high temperatures and pressures from volcanic activity.

Tatlock Quarry


R.I. Kelly High-Purity Calcite and Dolomite Resources of Ontario , 1996