Hellewell, who recently stepped down as executive chairman to become MD, will remain with the company in a part-time executive capacity, pending the appointment of a replacement.
Fellow founding Capricorn director Peter Langworthy has also resigned.
Lawyer Geoff Rogers and former Kalamazoo Resources MD Peter Benjamin have been appointed to the Capricorn board.
Terry Streeter has resigned as chairman of Alto Metals to pursue other business commitments.
Streeter, who had only been chairman of Alto since March, was appointed as a director of Emu this week, while another company he chairs, Moho Resources, listed on the ASX on Wednesday.
Existing Alto director and largest shareholder, Terry Wheeler, has been elected...