CHRIS UHLMANN, PRESENTER: At a memorial service on Friday, we said goodbye to our much-loved colleague Paul Lockyer who died in a chopper accident at Lake Eyre. Also lost were cameraman John Bean, who was farewelled today in Brisbane, and pilot Gary Ticehurst, who will be given a send off tomorrow.

Part of Paul's contribution in the last decade was to bring stories of rural and outback life to Australians everywhere, and fittingly, his final story for 7.30 was about a journey to remote Australia. It was also about gold and the hopes of one man to discover a fabled El Dorado in the outback.

Paul wanted his work to be seen, so here is his last story for 7.30.

BOB LASSATER, GOLD EXPLORER: I've eliminated a lot of area, a lot of country. But it's a terribly big place, I'm afraid.

PAUL LOCKYER, REPORTER: Bob Lasseter has made more than 30 trips through Central Australia trying to find a fabled reef of gold that his father Harold Lasseter claimed to have discovered.

BOB LASSATER: I need to keep searching. I made my mind up to accept that what me father said was correct. It's no good looking for something if you're half-hearted about it.

PAUL LOCKYER: Now 87, Bob Lasseter has devoted a big part of his life attempting to prove his father was right.

His wife Elsie has been his strongest supporter.

You've been out there with Bob yourself.

ELSIE LASSATER, WIFE: Yes, yes.

PAUL LOCKYER: You're convinced the reef is out there?

ELSIE LASSATER: Oh, I think it is and, I mean, I only married into it. Yes, I can't see that it's not.

PAUL LOCKYER: You're still convinced it's out there somewhere west of Alice Springs?

BOB LASSATER: Yes, I think so. Yes.

PAUL LOCKYER: When he was travelling through remote Central Australia in the early 1900s, Harold Lasseter claimed to have come across a reef of gold running up to 15 kilometres long.

BOB LASSATER: He noticed this rocks as though they had been laid out for road-making, picked up a piece and broke it and he examined it and could first see fine specks of gold in it.

PAUL LOCKYER: But it was much later, at the height of the Great Depression in 1930, that Harold Lasseter decided to return to his find. He convinced a group of Sydney business men that there was a bonanza waiting in the Outback and they formed the Central Australian Gold Exploration Company to undertake a search. Harold Lasseter, wearing the hat, suddenly found himself at the centre of a remarkable expedition.

This was a family portrait taken in Sydney four years earlier when Bob was a toddler. He was five when his father left for the Outback.

BOB LASSATER: I can remember writing a letter to him. I asked him to bring me back an emu and I had ideas of riding the emu around the paddocks of Ramsgate.

PAUL LOCKYER: The expedition headed out from Alice Springs, through some of the most desolate and unforgiving country in the continent, towards Western Australia. It made big news.

Gold fever, which had swept across Australia often enough since the 1850s, was again taking hold.

No expense was spared on the expedition, but there were many problems. The trucks broke down and the supply plane crashed, but still the party pressed on.

So this is one of the camps, was it? One of the early camps here?

BOB LASSATER: That was the main base camp, yes. Everything went from there. Made a trip out here to Mount Marjorie and back to there.

PAUL LOCKYER: But the expedition leader, Fred Blakeley, began to doubt that Lasseter had ever been to Central Australia or that a reef of gold existed.

BOB LASSATER: My father had definite ideas about where he wanted to go and the leader had other ideas and it led to arguments. And, yeah, I'm afraid that's - that was downfall of the expedition.

PAUL LOCKYER: Amid much dispute and acrimony, the mission was abandoned.

Lasseter was left to carry on into the desert with just one man and five camels. But as they trekked to the far west of the Northern Territory, Lasseter's last companion lost faith too and pulled out. Lasseter went on alone.

BOB LASSATER: And some people are saying that he created the whole thing just to create work for himself.

PAUL LOCKYER: Lasseter's search was to end in tragedy. His last two camels fled, carrying off most of his supplies. He sought protection in a cave from the searing heat, documenting his last days in a diary he buried there. A Northern Territory stockman, Bob Buck, was sent out in search of Lasseter, finding his body and the diary, which detailed his harrowing end, starving to death.

ELSIE LASSATER: And in his diary at the end, it's heartbreaking. It says, you know, "I can't understand why nobody's turned up." And yet, you know, he was made to be a ratbag.

PAUL LOCKYER: In his diary, Harold Lasseter claimed to have rediscovered the reef of gold and to have pegged it out again, just across the Northern Territory border inside Western Australia.

It rekindled interest, prompting the Australian Gold Exploration Company to launch another big expedition.

Again, it ended fruitlessly, fuelling further criticism of Lasseter, which rebounded heavily on the family.

BOB LASSATER: The negativity increased after that. That was sort of very early in the negative stage, yes. But as the years went on, it gradually got more so.

PAUL LOCKYER: How tough was it for Bob, living with those negative stories about his father?

ELSIE LASSATER: Oh, well, I think it was very hard, because he's not a vindictive type of angry person and some of the stuff was vitriolic.

PAUL LOCKYER: And you've retraced most of your father's steps in this area?

ELSIE LASSATER: Yes, yeah, most of it. Several times I found what I thought were landmarks, but I couldn't get them to tie up with one another.

PAUL LOCKYER: Bob Lasseter plans to resume his search for the fabled bonanza soon, embarking on another chapter in one of the greatest outback mysteries. He won't rest until he clear his father's name.

BOB LASSATER: I think if I can keep it up long enough, you know, I must find it.

ELSIE LASSATER: This is something that's really sort of had a cloud hanging over it. So, it would be nice.

BOB LASSATER: I'd get some satisfaction out of knowing that the people that have been comin' out with all these stories, you know, they were wrong.

CHRIS UHLMANN: The late Paul Lockyer. He, John and Gary will all be missed.