  The Iron Calorimeter (ICAL) detector at the India based Neutrino Observatory
(INO) is planned to be set up in an underground cavern with a rock overburden
of more than 1 km. This overburden reduces the cosmic muon flux by a factor of
10$^{6}$ with respect to that at sea level. In this paper, we examine the
possibility of a 100 m shallow depth ICAL (SICAL) detector. The cosmic muons
would have to be detected in a veto detector surrounding ICAL with an
efficiency of 99.99 % in order to have the same level of muon background
leaking undetected through the veto detector as at the 1 km depth underground
site. However, an additional background arises from interactions of cosmic
muons with the rock. Since the neutral particles produced in such interactions
can pass through the veto detector without any interaction, they can possibly
mimic neutrino events in ICAL. In this paper, the results of a GEANT4 based
simulation study to estimate the background signals due to muon induced
interactions with the rock for SICAL are presented.
