A minor amount is recovered from the mineral wulfenite.    From Wordnik.com.  [Molybdenum] Reference

Molybdenum is also found in the mineral wulfenite (Pb (MoO4), lead molybdate).    From Wordnik.com.  [Molybdenum] Reference

Deposits of wulfenite have been worked on a small scale in Arizona.    From Wordnik.com.  [The Economic Aspect of Geology] Reference

There were other mines that were quite productive though including a few gold mines along with uranium, asbestos, vanadinite and wulfenite mines.    From Wordnik.com.  [Desert News] Reference