Chile's copper mining companies have been offering assurances that their power supplies in the northern part of the country are far from the center of the magnitude 8.8 earthquake, but Mineweb correspondent Dorothy Kosich is warning that "shaky, blackout-prone energy supplies could impact many medium-sized mines in Chile and reinforce world market concerns about supply disruptions in a country that mines one-third of the world's copper." [right, Candelaria mine. Credit, Freeport McMoRan Copper & Gold]That would have big impacts for Arizona which produces 65% of copper used in the U.S.