NOVELTY - A feed stream comprising at least 30 mole% of carbon dioxide is cooled. The carbon dioxide in the feed stream is liquefied by indirect heat exchange of feed stream and liquid column bottoms stream. A portion of the liquid column bottoms stream is vaporized. Then, a portion of feed stream and stripping gas stream are introduced into a liquid-vapor contact column. Counter-current vapor liquid mass transfer is initiated in the liquid-vapor contact column. Finally, light component (A) is separated from stripping gas stream. Thus, separation of light components is carried out.    USE - Separation of light components used for recovering helium from carbon dioxide rich streams used for oil recoveries. The crude helium stream is stored and processed for further applications.    ADVANTAGE - The separation method effectively separates lighter components from gaseous mixture comprising high carbon dioxide content.    DETAILED DESCRIPTION - A feed stream containing gaseous mixture comprising at least 30 mole% of carbon dioxide is cooled. At least a portion of carbon dioxide in the feed stream is liquefied by indirect heat exchange of feed stream and liquid column bottoms stream. At least a portion of the liquid column bottoms stream is vaporized to form a vaporized liquid column bottoms stream. The liquid column bottoms stream is expanded before indirect heat exchange. Then, a portion of feed stream and stripping gas stream are introduced into a liquid-vapor contact column. Counter-current vapor liquid mass transfer is initiated in the liquid-vapor contact column, and a gaseous column overhead stream and liquid column bottoms stream are produced. Finally, light component (A) is separated from stripping gas stream. Thus, separation of light components is carried out. The stripping gas stream contains light component (B) having boiling point of lower than carbon dioxide and higher than the light component (A). The light component (A) is helium, hydrogen or neon. The light component (B) is methane, ethane, propane, nitrogen, argon or oxygen.