IT WAS a deal struck with a childhood handshake more than 30 years ago - a promise to strike it rich and solve Australia's greatest outback mystery.
And next week, Jeff Harris and three mates are due to set off on a boys' own adventure - in search of Lasseter's Reef, the legendary gold deposit.
One tool sets their expedition apart - Google Earth, cross-matched with sketches in Harold Lasseter's diary which they believe has led them to the reef.
''Once I'd figured out I could decipher the diary [using Google Earth] I was over the moon. I was staying up 24 hours a day working on it,'' Mr Harris, 41, a handyman of Tamworth, in New South Wales, said.
It has been more than 80 years since Lasseter died alone in the outback, searching for a quartz reef containing gold ''as thick as plums in a pudding''. He claimed to have stumbled across it three decades earlier while lost in the desert.
Mr Harris and his best mate, Brendan Elliott, learned of the legend as 10-year-olds in Wollongong. With a handshake, they pledged to find it. Over the next 30 years they pored over maps, searched archives and travelled into the outback. The breakthrough came five years ago, the night Mr Harris' son, Darcy, was born.
''I was sitting down celebrating the fact that I was a dad, and I happened to have the diary open, and Google Earth on the computer,'' he said. ''I connected Google Earth with a spot in the diary and matched it with the direction Lasseter was going.''
Open-access satellite imagery is closing the gap between large mining companies and lone prospectors, said Geoscience Australia minerals expert Richard Blewett. Software such as Google Earth and NASA World Wind can be overlaid with free, publicly available data, such as the recently released ASTER maps, which show mineral groups and compositions, and other data showing magnetics and gravity.
''You could have it on your laptop, with a GPS, you can drive along the tracks in real time and flick these different data sets on and off,'' Dr Blewett said. ''When you see things that are a bit anomalous, you might … do a bit of exploration.''
Entrepreneur Dick Smith, who is making a documentary about Lasseter's Reef, encouraged people to keep searching.
Bob Lasseter, 88, Harold's son, said age stopped him from continuing the search, but he hoped ''somebody will find it before I kick the bucket''.
Mr Harris and his mates plan to take soil samples from near the border of Western Australia and the Northern Territory.
''What I can prove is Lasseter was a great explorer, and he did find this place. For us, to prove that he was fair dinkum is good enough for me,'' he said.