Journal of Mining Engineering and Research. 2 (1): 28-35. June, 2020 www.j-miner.com doi:10.35624/jminer2020.01.04 1. INTRODUCTION Nowadays, undercut levels and footprint in caving methods are determined by Diering (2000, 2010) proposal. To apply this methodology for project economical assessment the necessary inputs are the deposit block model (including the economic valuation of each block commonly based on the estimated mineral grades), mining and processing costs and revenue factors used as mineral price coefficients, accounting for dilution with a vertical mixing model integrated based on the Laubscher model (1994). Each elevation is evaluated independently, generating vertical columns based on the block locations. The best height of draw (BHOD) for each column is calculated as the height that yields the maximum economic benefit, limited by a defined maximum height of draw. A discounted economic value is obtained for each column independently by adding the economic values of each block starting from the selected undercut, discounted by a vertical mining rate usually expressed as meters per year, up to the determined BHOD. Additionally, development costs can be included to account for the opening of each column. The columns with a positive economic value are included in the mining footprint at the current elevation. The value and ore tonnage of each potential undercut is calculated as the summation of the economic values and ore tonnages of all the columns included within the footprint, respectively. These economic value and ore tonnage are used as the main criteria to select the optimal level to start the extraction. The main reason to use the Diering methodology is the easy and fast evaluation of multiple levels for a selection of the best Impact of draw velocity profile on footprint definition for primary rock J. Contreras, Y. Marulanda, J. Valdivieso Universidad del Desarrollo, Ingeniería Civil en Minería, Santiago, Chile. ABSTRACT: In block/panel caving mines the footprint geometry and the undercut level height are key planning elements that have a bearing on the project final value. Selection of these parameters obviously depends on the economic objective, but it is also strongly influenced by rock mass characteristics that define column extraction capacity from draw points. This paper presents a simple methodology that allows defining the footprint and the best height of draw (BHOD) based on column extraction velocities, which are defined with the aim of controlling mass rock dynamic response while caving is propagated. The proposed methodology can be used by industry because of the ease of application. A study case is presented for a block model which is evaluated by both the proposed methodology and nominal profit estimation. RESUMEN: En minas explotadas por el método de block/panel caving, la cota del nivel de hundimiento y la geometría del footprint son elementos claves de planificación que definen el valor futuro de un proyecto. La elección de dicha cota y su geometría dependerá por supuesto del resultado económico esperado, pero también está fuertemente influenciada por las características del macizo rocoso en términos de la recuperación del mineral desde los puntos de extracción. El siguiente artículo presenta una metodología simple, y en línea con los requerimientos de la industria, que permite la determinación del footprint y la mejor altura de hundimiento considerando las velocidades de extracción de columna requeridas para controlar la respuesta sísmica del macizo al momento de generar la propagación del caving. Se presenta un caso de estudio sobre un modelo de bloques valorizado por la metodología propuesta y también con una valorización nominal. KEYWORDS: Draw height, footprint, steady-state caving, underground mine planning.