Simulating Time versus Mass Basis Sampling

Mechanical sampling from conveyors has historically been a staple in the iron ore industry when information related to chemistry, sizing, and moisture is required. In order to optimize automatic sample stations in a changing production environment, BHP Billiton Iron Ore (BHPBIO) developed an ExtendSim model that enables the various combinations of mass–mass, mass– time, time–time and time–mass to be investigated. Their sample station model can utilize actual (variable) feed rates to achieve high resolution and enables the simulation of sample size variation. Cutter speeds and other settings can then be adjusted to better optimize the performance of the sample station with regards to optimal sample size. The model can also assist process engineers in adjusting settings to better optimize the sample station and reduce unwanted events such as blockages. The model can be easily modified to conform to various sample station designs. It is anticipated that the sample station model will be used by process engineers when looking at optimization and trouble shooting. The model is also being used as part of a training package to help new engineers understand the workings of a sample station and the impact minor adjustments to settings can have on sample mass and therefore compliance.