A steam supply system includes a steam generator disposed to produce wet steam for introduction into a steam separator. The steam separator includes a saturated condensate outlet. A superheater receives dry saturated steam from the steam separator and produces superheated steam. An evaporator with an evaporator vessel having a saturated condensate inlet, a soluble solids slurry outlet and a dry steam outlet is in fluid communication with the saturated condensate outlet of the steam separator. Disposed within the evaporator vessel is a superheated steam heat exchanger having a superheated steam outlet and a superheated steam inlet which superheated steam inlet is in fluid communication with the superheater to receive superheated steam. The dry steam outlet of the evaporator is in fluid communication with a steam mixing vessel where the dry steam is mixed with superheated steam from the superheated steam outlet of the heat exchanger.