Ore Deposits

While there is certainly an element of luck in the discovery of an orebody, locating one is usually more than just the result of fortuitous circumstances. The formation of an orebody calls for special conditions which need to be understood by the mine finder.

Looking at the history of mining around the world, it is the areas of Precambrian shield rock, along with the much younger organic (mountain) belts of western North and South America that have yielded most of the world’s mines.

The Canadian Shield, occupying almost the entire central and northeastern portions of Canada, is one of the most prolific mining areas of the world – from the iron mines of Labrador to the gold and base metal mines of Val d’Or, Quebec, and Timmins, Ontario., all the way northwest to the gold mines of Yellowknife, NWT.

The Canadian Shield is composed of rocks formed during the Precambrian are (from 4.6 billion to 570 million years ago) and is one of the Earth’s original land masses. Many of these rocks have since been highly metamorphosed. This region, as well as the Precambrian shields on every continent, have proven to be rife with metal ore bodies, mostly because the mountain-building and other tectonic activity that leads to the formation of orebodies was widespread and intense in these early days of the planet’s life.

Hundreds of millions of years ago of erosion have since worn the old shield mountains down to their roots, bringing their ore nearer the surface.

The Cordillera, a band of relatively young and unstable rocks, covers an area that stretches from Alaska to British Columbia and the Pacific states down to Mexico and Central America and the Andes. It features complex rock structures favorable for metallic ore deposits, hosting some of the largest base metal and richest gold deposits found in this century.

More than half a billion years after much of the tectonic activity in the Earth’s shield ceased, the Cordilleran region became as active as the shields once were, leading to the formation of some of the world’s biggest ore deposits in places like British Columbia, Nevada and Chile.