Heavy mineral sands
are a class of ore
deposit which is an important source of zirconium
, rare earth elements
, the industrial minerals diamond
, and occasionally precious metals or gemstones
Heavy mineral sands are placer deposits
formed most usually in beach
environments by concentration due to the specific gravity
of the mineral grains. It is equally likely that some concentrations of heavy minerals (aside from the usual gold
placers) exist within streambeds
, but most are of a low grade and are relatively small.
Grade and tonnage distribution
|}The grade of a typical heavy mineral sand ore deposit is usually low. Within the 21st century, the lowest cut-off grades of heavy minerals, as a total heavy mineral (THM) concentrate from the bulk sand, in most ore deposits of this type is around 1% heavy minerals, although several are higher grade.
Of this total heavy mineral concentrate (THM), the components are typically
- Zircon, from 1% of THM to upwards of 50% of THM,
- Ilmenite, generally of 10% to 60% of THM
- Rutile, from 5% to 25% of THM
- Leucoxene, from 1% to 10% of THM
- Trash minerals, typically quartz, magnetite, garnet, chromite and kyanite, which usually account for the remaining bulk of the THM content
- Slimes, typically minerals as above and heavy clay minerals, too fine to be economically extracted.
Generally, as zircon is the most valuable component and a critical ore component, high-zircon sands are the most... Read More