Heavy Mineral Sands
The weathering over millions of years of igneous and metamorphic rocks, containing minerals such as rutile, ilmenite, zircon and leucoxene, results in sand grains with high densities. The grains are generally accessory minerals in quartz sands. They are concentrated by coastal, alluvial, and eolian processes that carry away the less dense quartz grains, leaving behind the denser heavy mineral sands. Most heavy mineral deposits around the world are found in ancient beach deposits that are now located far from today's oceans.Year of first production in Virginia: 1991
Location of first production in Virginia: Dinwiddie County
Virginia ranked second in the United States in both titanium and zirconium production in 2003 (Gambogi, 2003). Iluka Resources produced approximately 360 thousand tons of heavy mineral concentrate from its Old Hickory operation in Dinwiddie County in 2003. The Old Hickory heavy mineral deposit in Dinwiddie County was formed in beach and dune sands around 3 to 4 million years ago when the Atlantic Ocean was at higher elevations, and the shoreline was near Richmond. Heavy mineral concentrate production has increased by over 50 percent in the past five years. Ilmenite, leucoxene, rutile and zircon make up approximately 80 percent of the heavy mineral concentrate. These minerals are extracted from Pliocene-aged placer beach sands and all have industrial uses. Ilmenite, leucoxene, and rutile contain varying percentages of titanium dioxide which is primarily used for the manufacture of paint pigment. Rutile is also a source of titanium, a non-toxic metal capable of strengthening steel and is used in the aerospace industry, artificial joints and limbs, and heart pacemakers. Zircon is used as a ceramic glaze and in refractory bricks and foundry sand in steel manufacture. Initial processing is done on-site in the company’s concentrator. Gravity spirals are used to separate the denser heavy minerals and electrostatic and magnetic separators separate the individual heavy mineral constituents.
Heavy-mineral sand production in Virginia, 1991-2003.
Selected References:Gambogi, Joseph, 2003, Titanium: U. S. Geological Survey Minerals Yearbook, p. 78.1-78.9.
Gilmer, A. K., Enomoto, C. B., Lovett, J. A., and Spears, D. B., 2005, Mineral and fossil fuel production in Virginia (1999-2003): Virginia Division of Mineral Resources Open-File Report 05-04, 77 p.
Virginia Division of Mineral Resources, 1993, Geologic Map of Virginia: Virginia Division of Mineral Resources, scale 1:500,000.