I still haven't found the good places by myself. I found a stray dog, old mining roads and dead deer carcasses. Here is what findingrocksinar.com says: "Several abandoned lead mines may be reached by Arkansas Highway 43 north out of Ponca. Approximately 2.5 mines from Ponca and near the crest of the hill a dirt trail to the west is passable for a short distance downhill to near the mines."

Update 3/20/2011: Found the place this time with some other people.  There may be other tailing piles, but we visited a couple that included one with banded calcite and another near the mine entrance with galena in the dumps.  One old mine road can be found just after a guardrail going north out of Ponca on 43.  This mine road goes sort of downhill slightly and then uphill slighly after a few hundred yards.  One tailing pile with banded calcite is before the road zags back the other direction down the hill.  From the guardrail go straight down the hill and to the right and you'll find the mine entrance.  Use a metal detector to find galena.