Gordon Parry, 48, a property developer, from Westerham, Kent, was jailed for 10 years; Brian Perry, 53, a mini-cab firm owner, from Biggin Hill, Kent, was given nine years; Patrick Clark, 53, a former nightclub owner, of Chingford, north-east London, received a six-year sentence and Jean Savage, 48, a tobacconist, of West Kingsdown, Kent was given a five-year jail term.
The four laundered more than pounds 14m after bullion, stolen in the 1983 raid on a vault near Heathrow, was melted down and sold to unsuspecting buyers, including Johnson Matthey, who owned it. All had denied charges of handling and conspiracy to handle proceeds from the raid during the eight-month trial.
Judge Henry Pownall, sentencing them, said: 'You must have known you were playing for very high stakes indeed. There can hardly have been a more serious case of handling than this.'
A fifth defendant, Patrick Clark's son Stephen, 26, was acquitted at the weekend of taking part in the plot to launder profits from the November 1983 raid.
Despite the latest convictions, detectives believe gold worth pounds 10m is still missing. They named two men they still want to question. They are Savage's former lover, John Lloyd, and Geoffrey Greenlees, a former solicitor's clerk. Mr Lloyd, suspected of being part of the original robbery team, is known to have travelled to the United States. Mr Greenlees was last heard of in Jakarta, Indonesia, police said.
A total of pounds 15m cash and pounds 5m in property - proceeds from the robbery - has been traced by investigators.
The jury, which received round-the-clock police protection throughout the eight-month trial, was the second to be sworn to try the five defendants. A jury-nobbling scare halted the original trial last year after five months and an estimated cost of pounds 2.5m. A new trial started in January and cost an estimated pounds 3.5m.
A squad of 72 officers shadowed the jury of seven men and five women. Defence lawyers opposed the use of Scotland Yard detectives and wanted officers independent from the prosecution involved.
Detective Inspector David Shipperlee, of Scotland Yard, said officers were instructed not to socialise with jurors and to avoid striking up any relationship.
Jurors were followed 'at a discreet distance' wherever they went, but conversations were forbidden 'save to discover daily plans, or if there has been any untoward incident'. A telephone tap was ordered for any juror requesting it, Mr Shipperlee said.
A letter to the judge halted proceedings for nearly a month while police investigated. The letter, purporting to come from a juror's spouse, contained unspecified allegations. Jurors were questioned and later the judge said he was satisfied the letter probably came from an unknown mischief-maker.
He then discharged one of the women jurors, assuring her he did not think she had done or said anything wrong - but offered no further explanation.
The jury was reduced to 10 on Saturday when a woman juror was discharged after the court was told that her son had been badly injured in a cliff fall.