This Battle for Azeroth Mining leveling guide will show you the fastest way how to level your BfA Mining skill up from 1 to 175.
Mining serves three professions: Blacksmithing, Engineering, and Jewelcrafting, so it's really good combined with any of these. Check out my BfA Engineering leveling guide, BfA Jewelcrafting leveling guide, or my BfA Blacksmithing leveling guide if you want to level any of these professions.
Learning BfA Mining
The new BfA Mining skill is named differently for the two factions, but the name is the only difference between them.
[Kul Tiran Mining] is the Alliance version and [Zandalari Mining] is the Horde version.
Mining Trainers:
- Horde: You can find Secott the Goldsmith in Dazar'alor at the Terrace of Crafters.
- Alliance: Myra Cabot is in Boralus at the Tradewinds Market.
You can walk up to a guard in Dazar'alor or Boralus and then ask where the Mining trainer is. Asking the guard will place a red marker on your map at the trainer's location.
How to speed up leveling
The Battle for Azeroth expansion introduces three new items that you can use to speed up farming ores. You should use these if you can find them cheap at the Auction House, or craft it yourself if you can.
[Monel-Hardened Stirrups] - You can gather while mounted.
[Monel-Hardened Hoofplates] - Increase mount speed by 20%.
[Coarse Leather Barding] - Prevents you from being dazed. (mobs won't dismount you)
Every mob scales to your level in Battle for Azeroth, so it will be a lot harder to avoid the mobs attacking you while you try to farm ores. The combination of these three will make farming ores a lot easier, but the one I would recommend the most is [Monel-Hardened Stirrups], which lets you mine ores while mounted.
You should also enchant your gloves with 
[Enchant Gloves - Zandalari Mining] or [Enchant Gloves - Kul Tiran Mining].
Leveling BfA Mining (1-150)
You can level Mining to 150 in any of these zones below. Check out my Monelite Ore farming guide if you are looking for alternative maps.
Nazmir
Water walking mount or any water walking ability will make you farm in this zone a lot faster. If you notice that you farm too quickly, and the nodes are not respawning, you can take a bigger loop in the area and follow the red route, but the respawn rate should be fast enough on the yellow path.
Dustvar
If you notice that you farm too quickly, and the nodes are not respawning, you can take a bigger loop in the zone and follow the red route, but the respawn rate should be fast enough on the yellow route.
Zuldazar
This one goes through the central horde city, so I don't recommend it for Alliance players.
Stormsong Valley
Pretty easy to follow the route. There are a couple of ores underground around the middle of the map, but it's not always worth to go down there to get them.
150-175 in Nazjatar
You can still level in the old zones but the skill gains will slow down a lot at around 150 so I recommend switching to Nazjatar.
Don't forget to learn the rank 1 Osmenite Ore from your trainer 
Rolm / 
Instructor Ulooaka at Nazjatar. (You have to finish the first few intro quest at Nazjatar before you can see these NPCs.)
I got the most Osmenite ore following this route. Don't forget to check the caves marked with red X, sometimes the ores are deep inside the cave and you can't see them on your map until you go inside.
I hope you liked this BfA Mining leveling guide, congratulations on reaching 175!