Dump leaching
Encyclopedia
Dump leaching is an industrial process
to extract precious metal
s and copper
from ore
s.
Dump leaching is similar to heap leaching
, however in the case of dump leaching ore is taken directly from the mine and stacked on the leach pad without crushing where, in the case of gold
and silver
, the dump is irrigated with a dilute cyanide
solution that percolates through the ore to dissolve gold and silver. The solution containing gold and silver exits the base of the dump, is collected and precious metals extracted. The resultant barren solution is recharged with additional cyanide and returned to the dump.
This method of leaching is usually suitable for low grade ores because it is very low cost. However, it operates with slow kinetics and may take up about 1 to 2 years to extract 50% of the desired mineral.
Industrial process
Industrial processes are procedures involving chemical or mechanical steps to aid in the manufacture of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy industry....
to extract precious metal
Precious metal
A precious metal is a rare, naturally occurring metallic chemical element of high economic value.Chemically, the precious metals are less reactive than most elements, have high lustre, are softer or more ductile, and have higher melting points than other metals...
s and copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
from ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
s.
Dump leaching is similar to heap leaching
Heap leaching
Heap leaching is an industrial mining process to extract precious metals, copper, uranium, and other compounds from ore.The process has ancient origins; one of the classical methods for the manufacture of copperas was to heap up iron pyrite and collect the leachate from the heap, which was then...
, however in the case of dump leaching ore is taken directly from the mine and stacked on the leach pad without crushing where, in the case of gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
and silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
, the dump is irrigated with a dilute cyanide
Cyanide
A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....
solution that percolates through the ore to dissolve gold and silver. The solution containing gold and silver exits the base of the dump, is collected and precious metals extracted. The resultant barren solution is recharged with additional cyanide and returned to the dump.
This method of leaching is usually suitable for low grade ores because it is very low cost. However, it operates with slow kinetics and may take up about 1 to 2 years to extract 50% of the desired mineral.