Mining stars is a very AFK mining training method. Join the star miners discord to configure a plugin for the best experience. With that plugin setup, you can easily see where the stars are on what worlds:
Mining stars produces stardust which can be exchanged for gem bags in Falador, an easy way to get dragon stones and other uncut gems in quantities that are a viable way to train crafting.
Celestial ring
The celestial ring costs 2000 stardust at the same store, adds an invisible +4 boost to mining, and can be charged with the stardust (to store it) and that makes the ring give a chance to mine an extra resource.