BEIJING, Oct. 1 (Xinhua) -- Beijing is to close down at least 1,000 small coal mines before the end of next year's Olympic Games.     A circular jointly released last week by the Beijing municipal bureau of land and resources and the public security bureau ordered all unlicensed coal mines to cease operation immediately, dismantle their equipment, sack miners and hand in explosives within 15 days.     Owners who turn in themselves to police can have their punishment lessened or exempted, said the circular.     Illegal coal mine owners may face imprisonment with those exploiting more than 50,000 tons of coal looking at sentences of at least 10 years.     People who provide clues for the police can receive a reward of 1,000 yuan to 10,000 yuan (132 U.S. dollars to 1,320 U.S. dollars).     Beijing is believed to have more than 1,000 small coal mines in its western Fangshan and Mentougou districts.     Small coal mines account for two thirds of the deaths resulting from coal mine accidents in China. In 2006, accidents in small coal mines claimed 3,431 lives.