The company's fortunes and stock price have gone south after it failed to find commercial oil despite ambitious exploratory programmes in Brazil's remote Amazon Solimoes basin and off Namibia.
HRT said independent directors Thomas Ebbern, Peter O'Brien, Joseph Ash, Francois Moreau, Charles Lagana Putz and Oscar Prieto had all handed in resignation letters.
The company did not specify a reason, but the departures announcement followed disclosure over an apparent conflict over board elections.
HRT
