A few years after coming as a teenager to this Ghanaian town to prospect for gold, Yaw Ngoha had made enough cash to marry his sweetheart and build a house with a porch, to which he would later add a flat-screen TV and satellite dish. So when a town elder invited a doctor to talk to miners about the hazards of wildcat mining, "nobody listened," said the 36-year-old, sitting on a wooden bench on his porch in a lush banana grove.
