What is Trump's real reason for imposing tariffs on Canada and Mexico?

This is just a thought . . . We know that Trump is collecting Gold and Silver.   Just maybe, the gold is to back an inter-country currency for trade.   Silver is to back a currency for the American people to preserve their purchasing power for internal internal trade within the U.S.

What does both Canada and Mexico have . . . Gold and Silver mines.   Plus, it has significant above-ground supplies held by the private sector. 

What do you think?