Carbonate-hosted lead-zinc ore deposits and pyrite thus form. Commonly MVT deposits form by the combination of hydrocarbon pyrolysis liberating zinc-lead ions and sulfur to form an acidic solution which dissolves the host carbonate formation and replaces it with massive sulfide accumulations. This may also take the morphology of fault-hosted stockworks, massive tabular replacements and so forth. Porous limestones may form disseminated ores, however most MVT deposits are massive sulfides with knife-like margins between carbonate and sulfide mineralogies. Ore minerals in carbonate replacement deposits are typically lead sulfide, galena, and zinc sulfide sphalerite. Weathered equivalents form anglesite, cerussite, smithsonite, hydrozincite and secondary galena and sphalerite
National Mineral Development Corporation National Mineral Development Corporation </nowiki> NMDC Limited, previously known as National Mineral Development Corporation, is an Indian state-controlled mineral producer. It is 72.43% owned by the Government of India, under the administrative control of the Ministry of Steel. It is involved in the exploration of iron ore, copper, rock phosphate, limestone, dolomite, gypsum, bentonite, magnesite, diamond, tin, tungsten, graphite etc. It is India's largest iron ore producer and exporter producing more than 35 million tons of iron ore from 3 fully mechanized mines in Chhattisgarh and Karnataka. It also operates the only mechanized diamond mine in the country at Panna