A process for the extraction and recovery of bitumen from oil sands and a process for the treatment of tailings are disclosed. Bitumen is recovered in a process comprising contacting a polysilicate microgel with an ore sand oil to produce a froth comprising bitumen and a tailings stream comprising water, sand and clay fines. Preferably the tailings stream is dewatered and recovered water may be recycled to the extraction process. Polysilicate microgel may be carried through to a dewatering step and enhances flocculation in dewatering said tailings.