Tungsten concentrates derive from the mining of tungsten ore. Many locations throughout the world have tungsten ore reserves. There are mines on every continent but Antarctica.
Tungsten ore comes in several forms. See our previous post to learn about the main types. In underground mines, explosives dislodge material from the walls or floor of the mine in small areas. Open pit mines often use larger blasts before scooping up the ore. Underground mines usually have 1% or more tungsten oxide content. Open pit mines can have lower grades.
Producing Tungsten Concentrates
Cone crushers and ball mills reduce the size of the ore to under 2mm in size. Water carries the ore over shaker tables to concentrate it. It works like panning for gold in a river. The ore particles with lower density flow off as tailings while the higher density tungsten concentrate remains.
In small artisinal mines they do not have this equipment. The miners extract ore directly from rich veins. The weight of a fixed volume of the ore finds the density and value of the material. This material often needs more crushing. It needs to be smaller to have enough surface area for chemical processing.
A lab will find the amount of tungsten oxide in the tungsten concentrates. First grade material will have at least 65% tungsten oxide. Some impurities can be difficult to remove or are costly to dispose of. High levels of things like arsenic or uranium are not desireable. A full assay will help determine the value of the ore.
Buffalo Tungsten purchases tungsten concentrates regularly. We have recently updated our purchasing specifications. This shows the grade of material that we are looking to buy. We process the material at Niagara Refining. It is in our factory, so it gives us a secure source of material.