Relation between specific consumption/advance, in underground mining operations MAPE, study case Ecuador

Abstract

In Ecuador, Artisanal and Small-Scale Mining, MAPE, is an activity of national relevance. Historically there are three provinces with great potential and mining tradition, which are: El Oro, Zamora Chinchipe and Azuay. In this sense, in the province of El Oro, a large percentage of the economically active population depends directly or indirectly on the exploitation of highly profitable minerals. The key aspects for the development of underground operations of the MAPE regime are the drilling and blasting activities, where there is a great opportunity for improvement, efficiently managing the design of the grid, the execution of the drilling, the amount of explosive and the way it is charged, which are the factors that define the result of the blasting; same that is valued in function of the depth of cut or advance and of the uniformity of the structure of the section. For the development of this research, the baseline survey was carried out through technical visits to the study sector (Zaruma - Portovelo mining district), where traditional work procedures were observed, and then, based on the experimental method, technical variations were made in regarding the firing diagram, specific charge, specific perforation and type of explosive. These traditional (empirical) procedures, based on the driller's field experience, cause, among other things, the inefficiency of the advance, problems to maintain the dimensions of the section, over breaking of the working fronts, and one of the most relevant factors, the insecurity of the personnel who in many cases remain inside the mine for more than 10 hours.The main results show that the best tests were those that used the emulsion/ANFO (Amonium Nitrate Fuel Oil) combination, obtaining an advance percentage of approximately 95%, considered optimal within the operation. It was also evidenced that the Ammonium Nitrate commonly used in ASM needs a specific charge of greater power to meet the objective of the blasting.