In the week following its star-studded 20th birthday celebration, iron ore giant Fortescue has seen three high-profile resignations. Fortescue’s founder Andrew Forrest has cited differences in vision for the company, but neither CEO Fiona Hick, CFO Christine Morris nor director Guy Debelle have spoken publicly about the reason for their resignations. One thing we do know is that shareholders are uncomfortable. Are these resignations really down to employees not sharing Fortescue’s ‘green vision’? Or does the company have a governance problem? Guardian Australia’s senior business reporter Jonathan Barrett speaks to Jane Lee