Below is a picture of the plans for pebble mine supperimposed on the city of Seattle. I would use it as a place based earth science lesson as “hook”. The class can then discuss what they know about pebble mine and what they think about it. I would take great care to avoid adding my own personal opinions to the discussion. As a further note, I would data check this before I presented it. It is possible the image is an exaggeration.