The Asian owners of a billion-dollar Canadian coal mine are in talks to sell a majority stake of the mine for $2, underscoring the impact of slumping coal prices world-wide. Hong Kong-listed Up Energy Development Group Ltd. said Tuesday it has signed a memorandum of understanding to buy Grande Cache Coal by paying $1 each to its two current joint owners. Japanese trading house Marubeni Corp. 8002.TO -3.35% and Hong Kong-listed coal company Winsway Enterprises Holdings Ltd. 1733.HK +4.11%bought the Calgary-based coal miner in 2012 for 1 billion Canadian dollars (US$900 million).