  We set a preliminary 95% C.L. exclusion on the oscillation frequency of B0s -
B0s-bar mixing using a sample of 400,000 hadronic Z0 decays collected by the
SLD experiment at the SLC between 1996 and 1998. The analyses determine the
b-hadron flavor at production by exploiting the large forward-backward
asymmetry of polarized Z0 -> b b-bar decays as well as information from the
hemisphere opposite that of the reconstructed B decay. In one analysis, B decay
vertices are reconstructed inclusively with a topological technique,and
separation between B0s and B0s-bar decays exploits the B0s -> Ds- cascade
charge structure. In the other analysis, semileptonic decays are selected and
the B decay point is reconstructed by intersecting a lepton track with the
trajectory of a topologically reconstructed D meson. The two analyses are
combined with a third analysis described elsewhere to exclude the following
values of the B0s - B0s-bar mixing oscillation frequency: Delta m_s < 7.6 ps-1
and 11.8 < Delta m_s < 14.8 ps-1 at the 95% confidence level.
