Mining stats?

So I am looking into what profession gear to use. I looked up what each stat gives but couldnt find info on what increasing flat mining skill does? What do points after 100 do for you when youre mining?

I think it increased the quality of ore that you get. So you will get more rank 3 bismuth instead of rank 1 if you have higher skill.

I’m looking at my mining journal and I have a skill of 288 for bismuth. (100 from my mining level, 28 from my prof equipment and 160 from my skills that I spent knowledge on).

The +skill on your prof tools barely give anything it looks like and they are more important for the perception/finesse that they give.