A lot of things are overbough in the short term. I have a rule of thumb - after a 300% gain in a short period like a month or so, the risk/reward is no longer positive. NGC has almost done that and has a fair bit of resistance in the .60 - .80 area, so that's where I'd look to sell. I would then consider buying it back on a pull or a breakout. Just how I would do it.

Overall market (gold as well) looks a bit toppy - I expect a decent pull in April/May. The setup is the reverse of a normal year. Summer could be quite positive.