I've been digging for the past two hours over 15 locations and haven't received a +1 skill up over 930/950 skill
I've already assembled several pristine and all of the rare artifacts
the fragments are green quality now, meaning less chance of giving skill up
but instead of a steady pace, with some slowing down as skill increases, the skill up process has come to an almost full halt
trying to complete it for an achievement now but it has just become frustrating with the RNG involved, and would be no problem if fragments got changed to yellow all the way up to max skill, since there is no real benefit to the player if the skill is higher, like with other professions
I'm at the same point now. You fly around, do a full digside and nothing happens. Other professions are easy to raise, look at cocking. Even from 149 to 150 you only need 1 button click.
You can get to 950. its just a major pita, but I managed it despite only having green skillups to work with.