Deep enough .

Contrary to popular belief ,few hardrock mines in the West totally "played out" . Mines like the ones that tapped "the Lead" find a problem common to all mining : the further the mining gets from the surface ,the harder it is to turn a profit .Since the metals market has been in the toilet for two decades it will be a very long time before metals mining makes a comeback ,if ever .The last profitable mining technique is "leaching" where low grade ore is washed with cyanide ,which removes the gold . There are a couple of such operations in Northern Nevada .Also contrary to popular belief ,copper mining was always the biggest and most profitable of the Western mining operations . The Morenci-Clifton area in Southeastern Arizona has been an active mining district for 130 years .It was served by four narrow gauge railroads as late as 1937 . Unfortunately solid-state electronics has sharply reduced the need for copper ,and nearly all of the great copper operations are closed in the states as well as Northern Mexico . Incidentally ,Clifton Arizona is almost a perfect ghost town ,with at least three blocks of abandoned storefronts . Also a 20" gauge Porter on display across the street from Clifton's beautiful depot . Don't miss it if you visit Arizona this winter !