Leach process

Abstract

A leach process ( 70 ) comprising the following steps: i) Passing a metal containing waste material ( 72 ) from a mineral processing operation ( 96 ) to a biological leach step ( 74 ) in which a proportion of the metal is extracted into a pregnant leach solution ( 76 ); and ii) Passing the pregnant leach solution ( 76 ) from step i) to downstream metal recovery.

1 . A leach process comprising the following steps:
 i) Passing a metal containing waste material from a mineral processing operation to a biological leach step in which a proportion of the metal is extracted into a pregnant leach solution (PLS); and   ii) Passing the PLS from step i) to downstream metal recovery.   
     
     
         2 . A leach process according to  claim 1 , wherein the leach process further comprises a step in which the PLS from step i) is passed to an iron removal step iii) in which a significant proportion of the iron is removed from the PLS. 
     
     
         3 . A leach process according to  claim 2 , wherein the leach process still further comprises a step in which the PLS from the iron removal step iii) is passed to a solid liquid separation step prior to being passed to downstream metal recovery. 
     
     
         4 . A leach process according to  claim 1 , wherein the metal containing waste material is a product of a concentration step. 
     
     
         5 . A leach process according to  claim 4 , wherein the concentration step is a froth flotation step. 
     
     
         6 . A leach process according to  claim 4 , wherein the concentration step is fed with a ground or milled metal containing material. 
     
     
         7 . A leach process according to  claim 3 , wherein an underflow from the solid liquid separation step is passed to waste. 
     
     
         8 . A leach process according to  claim 3 , wherein a proportion of the underflow of the solid separation step is directed as seed to the iron removal step. 
     
     
         9 . A leach process according to  claim 1 , wherein the metal containing waste material is the waste product of a concentration step producing a concentrate for downstream processing, whereby metal is recovered from both the concentrate and the waste from the concentration step. 
     
     
         10 . A leach process according to  claim 1 , wherein the metal containing waste material is sourced from a tailings storage facility. 
     
     
         11 . A leach process according to  claim 10 , wherein the tailings storage facility is a dump or dam. 
     
     
         12 . A leach process according to  claim 1 , wherein the metal containing waste material is passed to a size reduction step or steps before being passed to the biological leach step. 
     
     
         13 . A leach process according to  claim 1 , wherein a biological heap leach process is combined therewith such that leach solutions are able to be fed therebetween. 
     
     
         14 . A leach process according to  claim 13 , wherein a portion of the PLS from step i) is passed to the biological heap leach process. 
     
     
         15 . A leach process according to  claim 13 , wherein at least a portion of a PLS produced in the biological heap leach process is returned to the leach process for downstream metal recovery. 
     
     
         16 . A leach process according to  claim 14 , wherein the portion of PLS passed to the biological heap leach is passed prior to any iron removal and/or solid liquid separation steps. 
     
     
         17 . A leach process according to  claim 14 , wherein the portion of PLS passed to the biological heap leach is post any iron removal and/or solid liquid separation steps. 
     
     
         18 . A leach process according to  claim 17 , wherein the portion of the PLS produced in the biological heap leach process that is returned to the leach process for downstream metal recovery is returned prior to any iron removal and/or solid liquid separation steps. 
     
     
         19 . (canceled)