O'Connell, the former boss of Eglinton Oil, is listing his Great Western Mining firm on London's OFEX market later this week.

The Dublin-headquartered company holds 21 gold, silver and uranium lode claims in the Little Huntoon Valley in Nevada. This area is thought to contain the so-called "lost Mexican gold mine". Prospectors and panhandlers have been searching for the motherlode for more than 130 years. The mystery began in 1868 at the end of the US Civil War, when saddlebags full of gold ore were found beside the bodies of a band ofMexican bank robbers.

Chased by two posses, the banditos had hidden out close to the Esmeralda and Excelsior mountain ranges in south central Nevada. However, they starved in the bitter winter. But when the bodies were found in spring, their saddlebags were full of gold coins and crushed gold-filled quartz ore. It sparked a gold rush and prospectors have been searching for the source of that gold ever since.

But in the mid-Eighties O'Connell's Eglinton Oil was in the area searching for its own fortune. Drilling around Carson City, company executives met up with an old-time prospector, called Dan Bracken, who told them about the "lost Mexican mine".

With a geologist's report suggesting that significant veins of ore lay in the Ming Troy area, O'Connell and his adventurers will be hoping this shaggy-dog tale has more than a nugget of truth.