ROKA KOANG, Cambodia Some 45 kilometers, or 28 miles, up the Mekong River from Phnom Penh, Voi Thy sat and watched as 12 boats pumped sand from the riverbed. Another 11 boats, weighed low by their quarry of freshly mined sand, were making the glacial journey past her home in Roka Koang commune, Kandal […]