  We use the average E(B-V) and ZnII column densities of a sample of z~1 CaII
(3935, 3970) absorption line systems selected from the Sloan Digital Sky Survey
(SDSS DR4) to show that on average, with conservative assumptions regarding
metallicities and dust-to-gas ratios, they contain column densities of neutral
hydrogen greater than the damped Lyman-alpha (DLA) limit. We propose that
selection by CaII absorption is an effective way of identifying high column
densities of neutral hydrogen, and thus large samples of DLAs at z<1.3 from the
SDSS. The number density of strong CaII absorbers (with rest-frame equivalent
width W_3935>0.5AA), is ~20-30% that of DLAs, after correcting for the
significant bias against their detection due to obscuration of the background
quasars by dust. On average these absorbers have E(B-V)>0.1mag; the dustiest
absorbers show depletions of refractory elements at a level of the largest
depletions seen in DLAs. For the first time we can measure the dust-to-metals
ratio in a sample of absorption selected galaxies, and find values close to, or
even larger than, those observed locally. All of these properties suggest that
a substantial fraction of the CaII absorbers are more chemically evolved than
typical DLAs. From consideration of the E(B-V) distribution in our sample, and
assuming CaII absorbers represent a subset of DLAs, we calculate that dust
obscuration causes an underestimation in the number density of DLAs by at least
8-12% at these redshifts. Finally, the removal of Broad Absorption Line (BAL)
quasars from the SDSS quasar sample increases the sensitivity of the detection
of reddening by intervening absorbers. To this end, we describe a new,
automated, principal component analysis (PCA) method for identifying BAL
quasars. [abridged]
