Dwarves

One of my personal favorite races in Middle-earth is the dwarvish race. The dwarves are very sturdy creatures who don't take orders from anyone (except from Gandalf). It is interesting to me how these underground dwellers are not evil. They spend most of their lives in caves and mines but unlike goblins which do do similar things, are not evil creatures but are generally good creatures. Tolkien, as far as I'm aware, was not the first person to create a dwarf but the concept still fascinates me. Tolkien in general liked to keep with themes for his creatures. The elves who are supposed to be the mightiest, are the most connected to nature and their own abilities. Them being connected to nature unlike their counter part, the orcs shows that the elves are good for using nature instead of the 'evil' machines the orcs use. Dwarves mine in middle earth and I would assume they have developed tools to help them mine efficiently over the ages. They however are not evil. Despite Being from underground, being stout and borderline fierce, the dwarves are not an evil race which interests me. With all the 'evil' characteristics, why did Tolkien not make the dwarves evil?