Gold was discovered in 1864 in Lyman New Hampshire which did create a bit of a gold rush buzz.
If you drive along the Wild Ammonoosuc River in Bath you will see Gold Prospectors all over the river looking for gold. From what I understand there is gold in the river and people have found signs of gold there but just little specs, nothing worth any money. Although a gold nugget was found in the 1980's but nothing significant ever since.
Just take a ride down Rt. 112 sometime and im sure you will find someone looking for gold in the river.
Not sure about any gold in Andover NH or at Ruggles mine in Grafton. But I think they may have done a little gold panning for the kids there at one point, maybe they still do but I think it was just for fun and educational purposes.