  We describe deep (40 orbits) HST/STIS observations of the BALQSO PG 0946+301
and make them available to the community. These observations are the major part
of a multi-wavelength campaign on this object aimed at determining the
ionization equilibrium and abundances (IEA) in broad absorption line (BAL)
QSOs. We present simple template fits to the entire data set, which yield firm
identifications for more than two dozen BALs from 18 ions and give lower limits
for the ionic column densities. We find that the outflow's metalicity is
consistent with being solar, while the abundance ratio of phosphorus to other
metals is at least ten times solar. These findings are based on diagnostics
that are not sensitive to saturation and partial covering effects in the BALs,
which considerably weakened previous claims for enhanced metalicity. Ample
evidence for these effects is seen in the spectrum. We also discuss several
options for extracting tighter IEA constraints in future analyses, and present
the significant temporal changes which are detected between these spectra and
those taken by the HST/FOS in 1992.
