Session: 10-09-01: Industrial Flows

Paper Number: 142512

142512 - Development and Application of a Mathematical Model for the Quantification of Induced Air and Its Extraction in Bulk Material Transfers Points 

One of the most utilized methods to prevent and mitigate fugitive dust in bulk material transfers is air extraction, whose flow is determined by the calculation of induced air.

The motivation behind this study stems from the limitations identified in theoretical-empirical formulations proposed in previous studies to determine the air required to be extracted. These existing calculation methodologies are not designed for unconfined spaces, do not consider the trajectory of the material, and were developed for flows rate of low magnitude.

This study develops a mathematical model aimed at quantifying the volume of induced air during the dynamic process of bulk material transfer and performing an analysis of various configurations in unconfined spaces, extending its applicability to confined scenarios to determine the polluted air to be extracted or the fugitive air that will be released into the atmosphere.

The underlying premise of the model is based on the principle that, during the material's free fall, which occurs in a defined period, all the material's natural interstices are occupied by the surrounding air, leading to a difference between the material's initial and final volume due to expansion. This, in turn, determines the volume of induced air per unit of time that has been incorporated after the fall.

To address this dynamic, the study employs a mathematical analysis that precisely models the material's real trajectory in unconfined conditions and examines the variations in induced air behavior when introducing different configurations and geometries of confinement, such as fixed or cushioned dead boxes and curved chutes.

In confined spaces, the analysis explores how a fraction of the induced air recirculates within the system or control volume analyzed, while another portion (which drags volatile material out of the area) is considered a contaminant emission and it must be extracted to prevent its release into the environment. Through measurements realized in an operating mining plant, the study empirically determines the percentage of recirculated induced air and, accordingly, the air that must be extracted in different transfer configurations, evaluating the benefit of passive dust control in operations like transfer from a conveyor belt to a storage hopper, transfer from a feeder or from one conveyor belt to another, transfer from a feeder to a crusher, and unloading from a truck or front loader (LHD) to a hopper.

The proposed model represents a contribution to the field of engineering in bulk material handling, particularly to the design of transfers, offering an additional tool for Computational Fluid Dynamics (CFD) simulations to represent induced air more accurately in transfers and a contribution to the integration with Discrete Element Method (DEM) simulations for efficient transfer design.

Presenting Author: Gonzalo Bozo Proconm

Presenting Author Biography: Gonzalo Felipe Bozo Nalli is a Mechanical Civil Engineer specializing in material handling and dust control in the mining industry. He has contributed to over ten mining plants, working with major companies like BHP, Antofagasta Minerals (AMSA), and Codelco. His expertise includes optimizing material transport systems, implementing dust control measures, and conducting particulate matter assessments. Bozo's technical skills have been instrumental in projects such as enhancing the dust mitigation system at BHP’s Spence Mine and improving transport systems at Codelco’s El Teniente.

Bozo has also presented his work at industry conferences, including "Granulacion del MP10 = Calidad de vida" at the RyP5 Congress in Viña del Mar in 2023, and he will present "Control del Polvo y Posibilidad de Erradicar la Silicosis en Minería Subterránea con Transporte Mecanizado" at the IV International Symposium on Mine Ventilation in Ouro Preto, Brazil, in September 2024.

Authors:

Efrain Bozo Proconm
Gonzalo Bozo Proconm