  A detailed investigation of hadronic interactions is performed using
$\pi^-$-mesons with energies in the range 2--10 GeV incident on a high
granularity silicon-tungsten electromagnetic calorimeter. The data were
recorded at FNAL in 2008. The region in which the $\pi^-$-mesons interact with
the detector material and the produced secondary particles are characterised
using a novel track-finding algorithm that reconstructs tracks within hadronic
showers in a calorimeter in the absence of a magnetic field. The principle of
carrying out detector monitoring and calibration using secondary tracks is also
demonstrated.
