The story I heard was it was stolen in the 70's and was found at a dump or something crazy like that
http://www.nospam49.com/rugbyleaguehistory/the-story-of-the-lost-rugby-league-world-cup-trophy/
The Original Rugby League World Cup trophy was stolen from a Bradford hotel whilst on open display in 1970. From there it took an amazing journey before it found its way back home to the RFL headquarters where it resides today.
The trophy was last held aloft by Australian Rugby League legend Johnny Raper after Australia’s 20-2 win over France at the Sydney Cricket Ground on the 10th of June in 1968 to claim the forth World Cup title.
The trophy was then brought to England prior to the 1970 World Cup and took pride of place in the Midland Hotel in Bradford, the headquarters of the visiting Australian Rugby League team.
It was stolen on the night of Sunday, November 1st, 1970. It was a shock to the games administrators and an embarrassment to the Australian Rugby League who had been responsible for its safe keeping.
Oddly enough, it was not the trophy to be used for the Final the following Saturday at Headingley. With the commencement of sponsorship, administrators decided to play for a more meaningless sponsored trophy and keep the original safe and on display at the Midland Hotel.
Twenty years passed, the Original World Cup was forgotten and life went on….until one day fate would see the Original World Cup fall into the hands of a man that was determined to find its original owner.
In 1990 the Original Rugby League World Cup was found. It was discovered in a ditch used for illegal tipping only a few miles from where it disappeared.