Available data on location and control condition of fuel-containing materials (FCM) being in Central Hall (CH) of оbject "Ukryttya" were analyzed. The characteristics of research holes drilled towards CH of оbject "Ukryttya" are adduced. The methods of inclination measurement of holes and structure of their route are proposed. New data on parameters of the holes drilled from room 515/3 towards CH floor are adduced. The recommendations on application of these holes to control nuclear-physical parameters of FCM accumulations in CH of оbject "Ukryttya" are given.