The disclosed invention provides a process for enhanced recovery of one or
more metal values from heap and/or dump leaching of ores containing the
metal values, the process comprising: (a) providing a high grade leach
solution obtained by heap or dump leaching of fresh high grade ore
containing a first metal value; (b) subjecting the high grade leach
solution to a first solvent extraction of the first metal value and
applying the resulting first aqueous raffinate to leach fresh high grade
ore; (c) providing a low grade leach solution obtained by heap or dump
leaching of partially leached ore or fresh low grade ore of the first
metal value; and (d) subjecting the low grade leach solution to a second
solvent extraction of the first metal value, separate from the first
solvent extraction of the first metal value, and applying the resulting
separate, second aqueous to leach partially leached ore or fresh low
grade ore, wherein the first and second aqueous raffinates are not
intermixed prior to being applied to their respective ores for leaching.
Alternatively, the first and second raffinates may be intermixed prior to
being applied to their respective ores for leaching, providing that the
aqueous raffinate applied to fresh high grade ore comprises at least 60%
by volume of the first aqueous raffinate and the aqueous raffinate
applied to partially leached ore or fresh low grade ore comprises at
least 60% by volume of the second aqueous raffinate.