Rich Thorium Mining in Burning Steppes (Classic - WoTLK)
Burning Steppes is another one of the high level zones that you're able to farm Rich Thorium in. One of the primary strengths of this zone is that it's so small and the enemies here are not high level. The majority of enemies that you run into throughout the zone will be in their mid to low 50s, drastically decreasing their agro radius.
Along with the Rich Thorium hwere you'll also find Small Thorium as well as many Mithril Deposits scattered throughout the zone. While you're running around and mining here, it's highly recommended that you stop at each of the blue circles on my map above aswell and check for Solid Chests.
There are camps of elite dragons throughout Burning Steppes and at each of these camps there's a rather high chance that a Solid Chest can spawn. Typically the chests don't have much of value in them, but it's a nice boost to your gold per hour for barely any extra work. If you have Skinning then you'll benefit twice as much since the dragons can be skinned for Black Dragonscales, which are the most valuable Dragonscales.
For more information on the Burning Steppes Chest Farming follow the link provided. That will tell you everything else that you need to know that this page doesn't.
In addition to Solid Chests having a chance to spawn at each of the Elite dragon camps, you'll also find them throughout the area marked "Pillar of Ash" on the map. There are a few different locations throughout this area which Solid Chests can spawn, once you learn those locations you can keep checking them as you run by.