The use of routine mineralogical characterisation of targeted process streams can have significant value for an operation. This is especially true where complex ore types or high variability in material characteristics occurs. When establishing the requirements for operational mineralogy it is important to consider all aspects of the process, from target stream identification, sampling and mineralogical analysis to data reporting and most importantly, how that data will be used to increase productivity of the operation.
General considerations in setting up a process mineralogy workflow:
Some key questions must be asked around what the goals of the analysis are before establishing the program, some examples for areas of focus include:
Each of these core goals requires a different level of analysis detail and different sampling regimes within the plant. Although it would be ideal to build a program that addresses each of these areas routinely, for large operations the scale of analysis required is prohibitive and a structured program that prioritises key areas for the operation is required.
A consideration in any operational mineralogy program is identifying the minerals or mineral characteristics to track. This will vary based on the desired goals and will not only relate to the ore minerals for the operation. Generally, ore minerals, deleterious elements and minerals and minerals with potential environmental impact should be monitored. For specific applications things like mineral texture and particle shape can also be monitored.
The routine analysis of samples should be undertaken at intervals relevant to the target metric but sufficiently spaced to allow a manageable volume of data. There is no point measuring metrics at close intervals if the data adds no value to the operation.
Generally, things like analysis of mineral deportment in tailings streams may be done at daily or even shift based intervals, while monitoring process units may be done on composites at the weekly or monthly level. The precise interval for each measurement should be determined based on measured variability of the feed material. If a geometallurgical model is available the intervals should be based on that.
In addition, analysis of composites from high interval analysis points should be undertaken routinely at a higher level of detail. For example, basic analysis of the tailings stream may be undertaken daily for copper mineral deportment but on a monthly basis a composite of those samples may be evaluated for gold deportment.
The core goals of the program should be used to determine where the samples are taken from. These areas should be assessed to define where existing sampling points exist or whether dedicated sampling points need to be installed.
An operational mineralogy program will only be successful if the operations team takes ownership. This will require sampling operators to understand where and why they are taking additional samples. Importantly operators and plant metallurgists should be trained in the use of mineralogical data to identify and diagnoses process problems. Supporting the operations team a metallurgist should be assigned as owner of the program, responsible for reporting of results and integration of the data into the operations and continuous improvement programs.
A requirement for operational mineralogy programs is to ensure that the appropriate data is reported and valid metrics are established, allowing that data to be used in evaluation of process health. This gives a basis to use the data generated and provides a benchmark of performance that can be built on. The metrics must be measurable in terms of reporting and demonstrated impact on process performance.
The operational mineralogy program needs to be structured in a manner that is readily integrated and embedded within existing operating practice. A program that is too data heavy or has too complex a reporting structure will experience poor uptake and the full benefits of the routine process mineralogy analysis will not be realised.
For more information on setting up an operational mineralogy program for yourself please contact us.