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SGS is the most experienced and trusted organization in the mineral processing industry.


Our core philosophy is to understand the variability of the parameters that affect flotation performance and then design, optimize or forecast based on these parameters. SGS provides laboratory test programs, including locked cycle testing, designed to achieve your objectives quickly and efficiently.

A locked cycle test is a repetitive batch flotation test. Locked cycle tests are conducted for two main reasons:

  • To assess if the flowsheet design and flotation reagent suite is stable
  • To produce a metallurgical projection for the sample tested

Locked cycle testing is the preferred method for arriving at a metallurgical projection from laboratory testing because the final cycles of the test are designed to simulate a continuous, stable flotation circuit.

In the basic locked cycle test procedure, a complete batch test is performed in the first cycle, followed by similar batch tests that have “intermediate” material from the previous cycle added to the appropriate location in the current cycle. These batch tests, or cycles, are continued in this iterative manner. The final concentrate and final tailings from each cycle are filtered and thus removed from further processing. At the end of the test, all the final and intermediate products are dried, weighed and subjected to chemical analysis. The test is balanced and a metallurgical projection is made.

The locked cycle test is very well accepted in the metallurgical industry, however the proper execution and resulting projections require the high level of technical expertise that SGS routinely provides. To confirm the flowsheet and produce a metallurgical projection, it is crucial that steady state is reached. SGS experts have the technical expertise and experience to determine:

  • The number of cycles to perform
  • The best method by which to assess if the test has truly achieved steady state
  • The best method by which to produce a metallurgical projection
  • The validity of the metallurgical projection

With over 70 years experience, SGS has done bench and pilot plant testing on thousands of flotation projects. Partner with us today for confidence in your locked cycle test results.