Leystone Deposit

To learn Rank 1 you first need to loot [item=124489] from leystone deposits and turn the provided quest in to Mama Diggs in Dalaran.

Rank 3 increases the amount of Leystone Ore you get per regular Leystone Deposit from 2-4 (at rank 1 and 2) to 3-5.

Okay for those who cannot seem to get the Rank 1 quest item I have a theory. Here is what happened to me and what I did.

1. 
   
2. Learned Mining and mined a Seam First (this is important).
3. 
   
4. Proceeded to mine a Basilisk.
5. 
   
6. Mined veins to no luck (around 20).
7. 
   
8. Unlearned/Relearned Mining.
9. 
   
10. Mined a Leystone Vein (First this time).
11. 
    
12. Got the quest item for Rank 1 and Legion Mining on the first go.
13. 
    

It is my theory: You have to mine from a vein first before anything else in order to get the quest item, without Mining bugging out.