We spoke with Molycop engineer Javier Jofre about how Molycop Tools can be used by plant metallurgists to optimise milling operations.
Molycop engineer Javier Jofre has played a key role in establishing Molycop Tools, a suite of tools that support plant metallurgists to optimise milling operations.
Molycop Tools incorporates a full set of digital simulators for conventional and semi-autogenous grinding applications with the corresponding mass balance and parameter estimation routines.
We spoke with Javier about how Molycop Tools can be used and the training program he put in place for plant metallurgists to use them.
Molycop Tools has a series of parameter estimators and simulators for conventional and semi-autogenous grinding using models known and accepted by the mining world.
Sampling data from the associated processes is required. With this data parameters are estimated, the simulators are tuned and then other scenarios are simulated in search of the optimum.
Figure 1: The virtuous circle of optimisation, which is the path proposed with the use of Molycop Tools to approach the operational optimum.
The part related to the conventional milling and classification processes partially goes back to the Center for Mining and Metallurgical Research, CIMM, specifically to the Mineralogy Division (pilot plant) where there were some programs for parameter estimation and simulation in Fortran language, which had been developed by Jaime Sepúlveda.
Later, in the early 2000s, Jaime developed version 1.0 that was launched at the Puyehue Hot Springs at the IX Symposium on Mineral Processing in 2001.
In my case I have developed various applications, from simple flow diagrams to some very complex ones such as the one in Figure 2, which require parameter estimators and ‘ad-hoc’ simulators. Also in version 3.0 launched at the XII Symposium on Mineral Processing, organised by Molycop Chile S.A., in 2012, it was my responsibility to develop the parameter estimator and simulator for bar grinding, based on the model of G. Grandy and D. Fuerstenau.The course ‘Process Simulation via Molycop Tools’ aims to train students in the use of the Molycop Tools software through real examples of industry application, complemented by the development and discussion of the associated theoretical concepts.
In the world of physical realities, it is not possible to see the net effect produced by modifying a variable, because reality is very rich in events. Therefore, it is only possible to observe superimposed effects of various situations – many of them unknown – that are occurring in unison. On the contrary, the simulator allows us to observe the net effect and the correct tendency of it, as a product of ‘moving’ a variable and, therefore, leaves open the possibility of prioritising the level of impact of the various operating and design variables associated with a given process.
In the context defined in the previous paragraph, the objective of the course is to promote among students the reflection on the causal relationships between the operating and design variables and the milling-classification processes. The establishment of the aforementioned relationships will be verified through the use of simulators of these processes.The students' training sessions are complemented by tasks that begin in class and end at home, being able to communicate with each other to clarify doubts and with the teacher through email.
We have also established as a complementary activity to invite two students per class to lunch, with the purpose of talking about their future plans and, especially, to guide them in pursuing their profession.
In the course taught in the first semester at the Catolic of Nort University, 11 students attended. The May class was one of several during the semester.
The students learned to use the Molycop Tools software, especially to relate the causes to the net effects, in order to visualise the effect or effects of moving an operational variable or design in the operation and, at the same time, to prioritise these variables according to their level of impact on the process. The above is supported by a theoretical framework that, among other aspects, includes the mathematical modelling of the grinding circuits – classification and SAG grinding, among others.
They were also challenged to modify a Molycop Tools spreadsheet according to certain conditions defined in class and, therefore, to create an ‘ad-hoc’ spreadsheet for a specific purpose.
Students learn to approach the operational optimum, defining a gap that ensures that the stress of the plant does not turn against the operation.
At the level of university students, the course Process Simulation via ‘Molycop Tools’ is taught in the case of the Catolic of Nort University. Twice a year, one course per semester, which has an elective character in the curricular condition. In addition, an intensive course is taught once a year, which is aimed at graduates and students of the last year. On this occasion, an intensive course will also be taught at the Catolic of Valparaíso University, among other courses for engineers and operators in process plants.
Regarding Molycop Tools courses that are not taught biannually at universities, the dates are agreed with the corresponding engineering directors, or with colleagues from the plants that make the request for the industrial training.