This is a link to the "Historic American Buildings Survey" done in the late 70s. Most the the structure is still standing but all the mechanical equipment has been removed pending restoration -- at least that was the plan. Note that this relates to the second mill after the first was destroyed by a flood in the 1890s.

http://memory.loc.gov/pnp/habshaer/ok/ok0000/ok0010/data/ok0010data.pdf