Acuña, EI & Feliú, A 2014, 'Considering ventilation on demand for the developments of the New Level Mine Project, El Teniente', in M Hudyma & Y Potvin (eds), Deep Mining 2014: Proceedings of the Seventh International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 813-821, https://doi.org/10.36487/ACG_rep/1410_59_Acuna (https://papers.acg.uwa.edu.au/p/1410_59_Acuna/) Abstract: The New Level Mine Project (NLMP) underground expansion represents the future of the El Teniente mines in Rancagua, Chile. With the expansion, the daily production rate is expected to be between 137 ktpd and a maximum of 180 ktpd. This represents an increase of slightly over 30% production for the project. The current plan consists of two multi-year development phases from 2012 to 2014 and from 2015 to 2017, with production planned to start in the end of 2017 or early 2018. The underground development of the NLMP starting from both surface and the current underground workings is already underway. However, the limited availability of airflow for development and energy to increase the mine’s ventilation for the 2012 to 2014 period motivated the study of ventilation mitigation strategies such as ventilation on demand to determine if it is possible to expand the number of working faces available, in an attempt to optimise the use of the current resources of the project such as energy. The ultimate objective is to accelerate daily development rates, which will produce additional savings and an increase of the value of the New Level Mine project. This paper presents the results of a preliminary study to estimate the cost and benefits of implementing ventilation on demand to increase the number of working faces and their energy efficient operation for the 2012 to 2014 development phase. The mine’s current ventilation strategy for the development of the NLMP is presented and used as the baseline to assess ventilation on demand. The results and decision are discussed in terms of the potential additional value generated by implementing the ventilation on demand strategy, considering energy savings, other benefits that are expected and the time required to pay for the initial capital cost.