  I describe a new scheme for selectively isolating high density low
longitudinal emittance beam particles in a storage ring from the rest of the
beam without emittance dilution. I discuss the general principle of the method,
called longitudinal momentum mining, beam dynamics simulations and results of
beam experiments. Multi-particle beam dynamics simulations applied to the
Fermilab 8 GeV Recycler (a storage ring) convincingly validate the concepts and
feasibility of the method, which I have demonstrated with beam experiments in
the Recycler. The method presented here is the first of its kind.
