Overnight accommodation is available in Imperial College's plush new Halls of Residence at Princes Gardens (Eastside Hall) or Beit Hall. Both halls are within 5 minutes walk from the Royal School of Mines. Accommodation is best booked through the College's own reservation system (which will enable you to get the best prices at the time of booking).
Book through: http://www.imperial.ac.uk/visit/summer-accommodation/ and click on the pink 'Book now' button
Alternatively: Make a Booking
You should select either Princes Gardens (Eastside Hall) or Beit Hall, both are described as being 'Hyde Park'.
Alternatively, there is a good choice of hotels both in and around London