There are two parts to the riddle;

1 The intrinsics about tthe ore body. Iron content, foreign metal content and the capital and cash cost of extraction.

2. The assumered market price.  The going price was $190 not so long ago and then the price plummeted by more than 50% last August to as low as $88.  In recent months the price had been around $118.

Clearly, if the cash cost plus handling plus freight to China is over $100 and the market price is $118, then the iron ore is worth little but at $160 it could be very valuable.

If cash costs and freight to the coast are $60 or less then in a $160 iron ore market the iron ore deposit is very valuable.

The freight cost to Asia should be $15 lower than the Labrador Trough cost

With or without iron ore, the deposit is large, economical to mine and in a perfect location