BILLINGS, Mont. (AP) — Conservation groups are asking a Montana court to block a long-disputed copper mine that they say would pollute a tributary of one of the state's most popular recreational rivers. Montana Trout Unlimited and other groups filed a lawsuit Thursday alleging state officials did not thoroughly study the environmental harm that could result from the Black Butte copper mine in central Montana. The Montana Department of Environmental Protection and Tintina Montana Resources were named as defendants in the complaint filed in state district court in Meagher County. State officials say the mine would have to abide by some of the most stringent conditions ever issued for a hardrock mine in Montana.