On the north side of the bridge that crosses the Ortega River in Jacksonville, Florida, a curved concrete wall hides 23,000 square feet of narrow corridors and floor-to-ceiling bookshelves that make up the Chamblin Bookmine. This treasure trove of printed material is mined daily by loyal customers Monday through Saturday. The Bookmine has also served as the flagship bookstore in the region over the last three decades. Inside, a maze of narrow corridors allows patrons to mine for books in roughly organized sections marked by hand-written signs. From hard and…