Between a Rock.../Quick guide

The Dwarven Scholar
If you haven't yet completed The Giant Dwarf quest, you will need to talk to the dwarven boatman to visit Keldagrim for the first time, after which you can take the mine carts from Grand Exchange to the city; the boatman is at the entrance upon first crossing the water.
 * Talk to Dondakan in the Keldagrim south-west mine and offer him your help.
 * Go to the library situated just north of the consortium and speak with the librarian.
 * Inside of the consortium, talk to the dwarven engineer.

Arzinian Avatar

 * Talk to Rolad (Fastest way is to teleport to the Falador lodestone and run north-east).
 * Go down the ladder to enter the dwarven mine.
 * Kill scorpions to get the first page.
 * Search the mine carts for the second page.
 * Mine the rocks in the mine to find the last page (Adamant rocks don't work, neither do the rocks in the dungeon connected to the mine).
 * Return to Rolad and read the book.

Yellow Stones

 * Head back to Dondakan talk to him, then use a gold bar on him.
 * Use a gold bar on a furnace with an ammo mould in your inventory/toolbelt and make a golden cannonball.
 * Go back to Dondakan and use the golden cannonball on him.

Cannon Ergonomics

 * Read the dwarven lore book to find the base schematics.
 * Talk to the dwarven engineer for another part of the schematics. Make your gold helmet on the anvils in the same room as the engineer while you are here.
 * Head under the White Wolf Mountain (Entrance north of the Taverley lodestone).
 * Go to the pub inside the tunnels and talk to Khorvak. No need to get him a beer, as he will still give you the final schematics.
 * Click assemble on any of the pieces.
 * Manipulate the schematics to get the desired result.

Striking Gold

 * Grab some gear to fight a level 72-80 enemy, along with your gold helmet.
 * Make sure to keep 6 to 15 free inventory spaces for collecting ore.
 * Head back to Dondakan and ask him to shoot you into the rock.
 * Mine the ores there. Get between 6 and 15 ores and head to the center room. More ores will lead to an easier fight.
 * Right click on the next ring of fire and select talk.
 * Kill the Arzinian Avatar.
 * Speak to Dondakan.
 * Quest complete!