Ore genesis accumulation of hematite gravels called "pisolites" which form channel-iron deposits. These are preferred because they are cheap to mine. Lead-zinc deposits are generally accompanied by silver, hosted within the lead sulfide mineral galena or within the zinc sulfide mineral sphalerite. Lead and zinc deposits are formed by discharge of deep sedimentary brine onto the sea floor (termed "sedimentary exhalative" or SEDEX), or by replacement of limestone, in skarn deposits, some associated with submarine volcanoes (called volcanogenic massive sulfide ore deposits or VMS), or in the aureole of subvolcanic intrusions of granite. The vast majority of SEDEX lead and zinc deposits
Mineral industry of Paraguay shown interest in the country, which could support continued economic growth and foreign direct investment (FDI) in new technologies well into the next decade. In 2006, Paraguay produced mostly cement, clays, iron ore, natural gas, pig iron, and steel. Paraguay's mineral reserves and resources were unidentified. The mineral industry of Paraguay mostly consists of Paraguayan state-owned firms. The structure of the country's mineral industry would, however, change, particularly in the natural gas sector, to a privately and/or joint-venture owned, government-regulated regime from one that was only government owned (Banco Central del Paraguay, 2007). FDI inflows to Mercosur increased to $25.1