  We use extensive classical molecular dynamics simulations to calculate the
thermal conductivity of a model silica glass. Apart from the potential
parameters, this is done with no other adjustable quantity and the standard
equations of heat transport are used directly in the simulation box. The
calculations have been done between 10 and 1000 Kelvin and the results are in
good agreement with the experimental data at temperatures above 20K. The
plateau observed around 10K can be accounted for by correcting our results
taking into account finite size effects in a phenomenological way.
