Orebodies right under your nose

The information was contained in “A Survey of Known Mineral Deposits in Canada that are not Being Mined,” that I co-authored with Richard Annis and Marcel Vallee, first published in 1976 by Energy, Mines and Resources. The present David Bell mine at Hemlo was listed in this publication under the name “Lake Superior deposit,” latitude 48 degrees 41%31%%, longitude 85 degrees 54%33%%. It was then believed to contain 89,000 tons of mineralization averaging 0.27 troy ounces of gold per ton.

The presence in that publication of profitable leads such as Hemlo is not unique. Many other Canadian mines now in production (or being prepared for production) appeared in this publication, which was based on the Federal government’s Sector’s National Mineral Inventory files, long before they were recognized to be mineable orebodies.

In fact, a significant number of them, including most of the Hemlo gold deposit, were on open ground, available for staking. Although the mining claims that covered the Lake Superior deposit were in good standing when the publication appeared in 1976, they became available for re-staking when they lapsed in 1980.

EMR’s National Mineral Inventory file has information for some 20,000 mineral occurrences, unmined mineral deposits, and present and former mines. These cover industrial minerals as well as metals. The National Mineral Inventory is a tool that is too seldom used for mineral exploration.

NMI mineral occurrence records contain: location; metals or minerals in the deposit; history of exploration and development; history of production (if any); summary of the geology and a list of the reference publications from which the information was obtained. This information is available to the public on 2-sided 8 1/2×11 inch file cards at 25 cents each, or custom computer reports keyed for specific exploration targets or deposit characteristics of particular interest to a customer. The complete data base index material is available in computer-processible form.

When I was EMR’s commodity specialist for gold, I was visited in early 1980 by an “explorationist” who wanted to know where to look for gold. I told him in considerable detail about “Deposits Not Being Mined,” and about NMI. I also told him that in the area in which he was interested, I was certain that occurrences and abandoned former mines described in the National Mineral Inventory records offered significant opportunities for discovery of new orebodies. This prophecy has since been abundantly fulfilled. His answer was “those occurrences are all old stuff.” I wonder how many others are still making the same mistake?

When I was exploring for uranium. I had a standing order for all National Mineral Inventory cards relevant to uranium. I plotted these on photomosaic maps that I made from satellite photos. A relationship, which had not been evident on the geological maps, between faults visible on the satellite photos and uranium occurrences became obvious. This led to new showings that warranted drilling. Imaginative exploration geologists can no doubt think of many other profitable uses for National Mineral Inventory information.

Some companies order sets of all National Mineral Inventory cards for particular commodities or areas. Others have complete sets of all 20,000 cards: at about $6,000, this is a cheap exploratio particular commodities or areas. Others have complete sets of all 20,000 cards: at about $6,000, this is a cheap exploration tool.

Now, I will make you another offer. Andy Sozanski, who heads national Mineral Inventory, will be at Booth “C” at the Prospectors and Developers Association annual convention in Toronto on March 5-8. He will have information about the National Mineral Inventory and copies of publications that you can obtain in English or French: (1) the most recent update of “Canadian Mineral Deposits Not being Mined”; (2) “Base Metal Deposits and Occurrences in Canada, February 1989”; and (3) “Gold Deposits and Occurrences in Canada”.

There’s probably another Hemlo or two in there.003 Donald Cranstone is with the economic and financial policy branch, mineral policy sector of Energy, Mines and Resources Canada.

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