  The proposed magnetized Iron CALorimeter detector (ICAL) to be built in the
India-based Neutrino Observatory (INO) laboratory aims to study atmospheric
neutrinos and its properties such as precision measurements of oscillation
parameters and the neutrino mass hierarchy. High energy charged current (CC)
interactions of atmospheric neutrinos with the rock surrounding the detector
produce so-called "rock muons" along with hadrons. While the hadron component
of these events are absorbed in the rock itself, the rock muons traverse the
rock and are detected in the detector. These rock muon events can be
distinguished from cosmic muons only in the upward direction and can provide an
independent measurement of the oscillation parameters. A simulation study of
these events at the ICAL detector shows that, although reduced in significance
compared to muons produced in direct CC neutrino interactions with the
detector, these events are indeed sensitive to the oscillation parameters,
achieving a possible $1\sigma$ precision of 10\% and 27\% in determining
$\Delta m_{32}^2$ and $\sin^2\theta_{23}$, respectively. Hence a combination of
the standard atmospheric neutrino analysis which is the main goal of ICAL, with
these rock muon events, will improve the precision reach of ICAL for these
parameters.
