To the salt mines

What does it mean when someone says 'We will send her to the salt mines'?

We will give her a difficult or boring work assignment. (Depending on the situation, this may mean demoting her.) ~rb

The origin being in Imperial and Soviet Russia, in which rebels and dissidents of all kinds were routinely condemned to be sent to Siberia to work in the Siberian salt mines. (VSD)

You are, of course, right about the origins of the phrase, but I seem to remember reading that it was based upon a myth.

Mining salt (like any other sort of mining) was - and still is - highly skilled work and sending prisoners to do it would not have been a tremendously sensible idea.

DFG