Human nature is motivated primarily by base emotions (greed, envy, arrogance and self-indulgence) and to some extent, by rationality.
Our biggest problem is to make rationality a more important component of human decisions. We have come a long way towards this goal in the past few hundred years but there remains much to do.
The proposed Ajax mine provides a good example. Most people are motivated by their immediate self-interest.
Those who think the main effect of the mine on their immediate self-interest is to increase their income are in favour and those who think it is to decrease their quality of life are opposed.
Few think of the effect on anyone but themselves.
The taxes that the mine would produce are in the immediate self-interest of our politicians, so they are generally in favour, although they often hide their belief to avoid giving offense to any member of the electorate.
If a rational decision is to be made, the mining company will be left with the decision about where to locate its operations.
But our politicians must make it clear that the mine will be held responsible for any external costs of its operation (to be determined in a court of law).
The mine should know that if it imposes external costs on the community, it will be held responsible.