The third of the big three mountain resort operators went public last week, trucking snow into the New York Stock Exchange for the occassion. The American Skiing Company offered 14,750,000 shares of common stock Nov. 6. The stock opened at $18 per share but closed the day at 16 15/16. ASC owns seven mountain resorts, including the recently purchased Steamboat in Colorado and Heavenly Resort on the California-Nevada border. Proceeds from the public offering, which had an opening value of $265,500,000, will be used to finance the Steamboat and Heavenly purchases. ASC’s two major rivals, Intrawest and Vail Resorts, are both public companies. Vail stock has been trading at about $27 and Intrawest in the $18 (U.S.) range.