We present Li abundances for 73 stars in the metallicity range -3.5 < [ Fe/H ] < -1.0 using improved IRFM temperatures ( Casagrande et al .
2010 ) with precise E ( B-V ) values obtained mostly from interstellar NaI D lines , and high-quality equivalent widths ( \sigma _ { EW } \sim 3 \% ) .
At all metallicities we uncover a fine-structure in the Li abundances of Spite plateau stars , which we trace to Li depletion that depends on both metallicity and mass .
Models including atomic diffusion and turbulent mixing seem to reproduce the observed Li depletion assuming a primordial Li abundance A _ { Li } = 2.64 dex ( MARCS models ) or 2.72 ( Kurucz overshooting models ) , in good agreement with current predictions ( A _ { Li } = 2.72 ) from standard BBN .
We are currently expanding our sample to have a better coverage of different evolutionary stages at the high and low metallicity ends , in order to verify our findings .