Sequential Leaching

Sequential or diagnostic leaching (DL) is an important procedure used as a diagnostic tool to establish the exact location of copper minerals. This multi-step ambient leaching procedure is a crucial tool when dealing with variability in deposits with complex copper mineralogy.

Sequential leaching is a well-established testing procedure, which has been in use since the 1980s. Sequential leaching is a complex procedure. Staff conducting these tests require a high level of mineralogical expertise and strictly controlled laboratory quality control if the test results are to be accurate and reproducible. SGS is backed by a global network of mineralogists, chemists and engineers. Our independent third-party test results are readily accepted by financers worldwide.

SGS strictly controls time, temperature, chemistry and other parameters during sequential leaching. Following an initial mineralogy assessment, SGS experts subject the ore to a sequence of steps:

1. A 20°C (or heated) sulfuric acid digestion for one hour
2. A 20°C (or heated) cyanide digestion for 30 minutes
3. Digestion with aqua regia or standard four-acid digestion

We then calculate the sum of copper digested during these three digestions and compare the calculated copper to a total copper assay. The data gathered during this testing is important for flowsheet development and pilot plant design.

SGS sequential leaching is a reliable solution to complex copper mineralogy in gold orebodies. Sequential leaching is one of several pressure and ambient leaching treatments that we provide. Contact us early in your planning and proposal stage to determine which leaching procedure will optimize your pay metal recovery and improve your bottom line.