Which is the correct sentence structure in the sentence New Mexico has many ghost towns that were abandoned when their silver mines were depleted and these towns are popular tourist attractions?

The correct sentence structure is to separate the two independent clauses with a conjunction or punctuation. For clarity, it can be rewritten as: "New Mexico has many ghost towns that were abandoned when their silver mines were depleted, and these towns are popular tourist attractions." Alternatively, a semicolon could be used: "New Mexico has many ghost towns that were abandoned when their silver mines were depleted; these towns are popular tourist attractions."