Ores with particles in the size range of between about 10 and 25 mm can be treated. Depending on the ore massdensity distribution and copper density distribution, between about 20 to more than 40% of the low density ore could potentially be rejected prior to wet grinding with little loss of valuable copper.
The maximum permissible current density of copper in open air is approximately 3.1×10 6 A/m 2 of cross sectional area, above which it begins to heat excessively. Copper is one of a few metallic elements with a natural color other than gray or silver. Pure copper is orange red and acquires a reddish tarnish when exposed to air.