Ventilation planning for mining of the Sarvisuo Lode in the Orivesi mine

Orivesi mine is a 720m deep gold mine in Finland. The mine is currently, on August 2005, in a standby mode, to which it was placed in the beginning of 2004, when the steeply dipping ore bodies narrowed with increasing depth and mining was not considered feasible anymore. However, more ore was soon found nearby during an exploration program and a feasibility study concerning the Sarvisuo Lode was started in autumn of 2004. Mining plans for the Sarvisuo Lode consist of establishing access from existing drives that extend from 285 m and 525 m levels from the main Orivesi decline to the vicinity of the lode. As a part of the mine planning, preliminary ventilation study was conducted during the winter 2005. This study addressed the issues of ventilation requirements as well as alternative implementation possibilities for ventilation. In this paper the survey and simulation results for the study are presented and the functionality of suggested different shaft alternatives is evaluated. Possibilities to combine the old infrastructure with new workings were considered essential and thus the subject attracted a lot of attention. During planning two different mining options called 'small project' and 'large project' were investigated. Shaft alternatives were tried out for both. Also a set of different requested detail studies either concerning both or one of the mining options were performed and compared. A decision to continue mining in the Orivesi mine was released on July 2005. Mining of the Sarvisuo Lode is planned to start in spring 2006.