I just used 10% for the ease of explaining the math, the tax...

I just used 10% for the ease of explaining the math, the tax break Canadians get is irrelevant to your investment unless you are Canadian.

Using @greenhart numbers from his link above.

Mountie invests $1000 in flow through shares on the mining side. After tax breaks, his net cost is $375
Mountie then gifts those shares to a charity for say an additional 10% tax break off the original cost i.e. $100. Total after tax cost is $275.
Mountie has now helped a mining company and a charity get funds worth $1100 from the government at his personal cost of $275. Instead of getting taxed on $1000 income, he only gets taxed on $275, and he gets to feel good about himself.

The biggest and most important issue for an investor to look for with flow-through shares is this:
Is there a block trade involved?

No - shares will need to be held for two years and hence support the SP closer to the CAD/AUD equivalent price paid.
Yes - brokers just got cheaper shares to offload for an instant profit.

And if your MD and BoD don't put this info front and centre of the headline announcement, then beware.