Soil, quarry waste rock and overburden. Some colonial governments eventually had to create legislation prohibiting the jettisoning of ballast into the major shipping harbors. There were also many passengers, slaves and goods being shipped to the Americas from Europe, Africa and the Caribbean, adding significant weight to the inbound ships. Plentiful amounts of hematite were obtained from iron ore producing mines and quarries. I live just a few miles from an iron furnace and ore mines from 1727. Much of the ore was hematite.