  The radial motion of massive particles in the equatorial plane of the Kerr
black hole is considered. Screening of the Hawking radiation and shielding of
the Penrose process are examined (both insides and outside the ergosphere) and
their effects on the evaporation of the black hole is studied. In particular,
the locus and width of a classically forbidden region and their dependence on
the particle's angular momentum and energy is analysed. Tunneling of particles
between the boundaries of this region is considered and the transmission
coefficient is determined.
