This basic method is applied to evaluate plant performance and to improve results. It is a systematic approach to problem solving in an operating plant and therefore, the preferred method used by the Consulting Group.

Step 1: Plant auditing, surveys and data analysis

In this step the following tasks are performed:

• Summation of the metallurgical data, reagent consumptions, observations from the log books of the operation and the geological records.
• Plant surveys of all circuits, including grinding, classification, flotation, dewatering, etc. The surveys are performed several times.
• Cell-to-cell sampling of the rougher and cleaner circuits to calculate flotation rates.
• Preliminary laboratory tests on actual mill feed.

The collected data will be analyzed using the SMB Consulting "paremetric model", specifically developed for performance evaluations in operating plants. The result of this evaluation will point out specific problems and will indicate possible solutions.

Step 2: Laboratory development tests on mill feed and plant pulp.

The design of the testwork program is generated in Step 1. In addition to the work on mill feed, tests are performed on plant pulp for confirmation. If test results suggest that no additional equipment is needed to overcome the problems, no further laboratory work is required. If capital spending is involved the changes should be piloted with actual plant pulp. From this work the operating conditions can be developed for transfer to the plant.

Step 3: Implementation of proposed changes.

Changes identified as beneficial to the plant operation, such as reagent scheme, flowsheet modification and additional equipment, will be transferred to the plant and commissioned together with the operators. Participation of the plant metallurgical staff in the execution of all three steps is important.