sentences:  MVT and Irish type deposits are commonly associated with a 'dolomite front' alteration, which manifests as a yellow-cream wash of dolomite (calcium-magnesium carbonate) within calcite-aragonite assemblages of unaltered carbonate formations.Most ore bodies are quite sulfidic, and most are very low-iron, with pyrite-marcasite contents typically below 30% of the mass of sulfides.This makes MVT lead-zinc deposits particularly easy to treat from a metallurgical view.