Question: Enigma key - Stage 1 -

ED-5 Grade 1 fragments ... Are they elusive?

Mined for an hour - nothing -
Hunted 200 punies - nothing -

Am I missing something, do I need to hunt bigger mobs to get them or am I stupid ?

Usually you get them after few loot events. But sometimes it takes a lot more - happened to me too. Eventually you will get your fragment but you can also abandon current fragment mission and retry in an hour.