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DEM analysis in a mobile crushing plant: a success story

The mobile crushing plant concept is not new to mining professionals. However, its use has only become more widespread in recent years, due to advances in related areas of engineering. When compared to stationary systems that rely on off-highway truck transportation, mobile crushers have significant advantages, the main ones being:

  • Cost reduction
  • Reduction of manpower required for the operation
  • Decreased fuel consumption
  • Decreased levels of CO2 emissions

Aiming at competitive ore production, coupled with the most sustainable, modern solutions and without the use of off-road trucks for transporting materials, one of KOT Engineering‘s client wished to upgrade the nominal and design capacities of one of its mobile crushing units from 9,500 to 10,500 and 11,500 to 12,600 tons per hour respectively. This system can be seen in the image below.

Overview of the mobile crushing system.
Overview of the mobile crushing system.

With the change in production capacities, both nominal and design, the variation in the mass flow rate and the speed of operation of the machines’ conveyors directly impact the material’s behaviour in the receiving and unloading chutes of the mining machines. In this blog post, we will discuss the verification of the receiving feeder and an intermediate ore transfer chute of the plant by means of discrete element method (DEM) and Rocky DEM simulations.

3D modeling

The first development stage for the discrete element analysis was the preparation of three-dimensional models of the feeder and the intermediate material transfer chute. As these are models of material flow surfaces, details such as inspection doors and windows and other auxiliary devices were not modeled. Such components are generally not considered in the analysis because they do not influence the material flow in the structure significantly. Images below show some of the models developed.

Three-dimensional model of the feeder.
Three-dimensional model of the feeder.
Three-dimensional model of the intermediate chute.
Three-dimensional model of the intermediate chute.

Analysis of material and feeder

KOT engineers received characterization tests of the material that is transported and performed the calibration of the material model from its characteristics. The characterization has the objective of raising material properties that are input parameters for the simulations in Rocky DEM (particle-particle and particle-wall interaction properties of the chute). The tests also help in understanding the flow of the ore stream.

Feeder DEM model.
Feeder DEM model.

The DEM analysis of the feeder indicated the operating speeds of the equipment for some of the various material conditions that are processed by the equipment, and an appropriate type of operation was indicated for each variation of material handled. Thus, the values obtained are in accordance with the proposed re-powering of the mobile crushing unit and serve as a reference for the operation of the equipment.

Overview on the left and center plane on the right of the DEM model of the feeder.
Overview on the left and center plane on the right of the DEM model of the feeder.

Intermediate chute analysis

The simulations with the re-powered design showed that the chute did not support the increased capacity of the conveyors for the operating conditions, since problems related to clogging were identified. Thus, a redesign of the component was indicated. Regarding the impact table loads, it was verified that the rollers in this region are able to operate under the new capacity. In addition, the analysis indicated that the plate identified as a deflector does not receive impacts from the material flow.

Clogging analysis of the mobile crushing unit's intermediate chute.
Clogging analysis of the mobile crushing unit’s intermediate chute.

Simulations versus real conditions

Computer simulations can be both supplemented with information collected in the field during operation, and endorsed against real conditions that exhibit great similarities. The capillarization of computational techniques has provided both the refinement of methodologies for their execution and the acceptance of the results obtained through them. The video below shows the comparison of footage of the operation of the feeder of the mobile crushing plant in question with the result of its DEM analysis.

Comparison between the operating conditions and the DEM simulation result of the feeder.

This blog post was originally published by KOT Engineering.

KOT Engineering

With over 28 years of history and various services provided with excellence in the international market, KOT promotes the integrity of its clients’ assets and collaborates in solutions to engineering challenges. For this integrity, it uses tools for calculation, inspection, instrumentation and monitoring of structures and equipment.

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