This paper describes the development and modelling of ventilation and gas management strategies to be employed in the re-entry of the Pike River Mine Drift together with results of nitrogen injection to date. The purpose of re-entry is for forensic examination, possible recovery of bodies and to bring, at least some, degree of closure to the families of the 29 miners who were killed in the Pike River mine explosion on
19th November 2010. Following the initial and subsequent explosions at the mine, it was finally sealed in 2011.
A review of the situation in 2017 led to the establishment of the Pike River Recovery Agency (PRRA) in January 2018. The PRRA is charged with the task of developing and implementing a plan to re-enter the 2.2 km access drift if deemed technically feasible and safe to do so. At the time of commencing this re-entry planning work, the mine was effectively sealed and inert by virtue of methane concentrations being in excess of 95%. A series of design reviews and risk assessments have led to a force ventilation system being selected combined with application of nitrogen to control atmospheres in the drift and coal mine workings during various re-entry phases. The recovery plans developed by PRRA involve initial purging with nitrogen followed by re ventilating the drift in stone with fresh air whilst simultaneously maintaining an inert (<5% oxygen) nitrogen methane atmosphere in the coal mine workings. the current plan is then to re-enter the drift from the portal under force ventilation with forensic examination, involving members of the new zealand police force if significant forensic evidence is discovered. the first phase of nitrogen injection to the drift commenced on 18th december 2018 and was successful. infrastructure for the next phases of re-entry are currently being installed and tested. based on monitoring data available so far, it is anticipated that the identified plan will progress to the next phases of re ventilation then re-entry during the first half of 2019. citation:hughes, r, moreby, r, poborowski, b and rowland, j, 2019. ventilation and gas management strategies for re-entry to pike river mine drift, in proceedings australian mine ventilation conference 2019, pp 308318 (the australasian institute of mining and metallurgy: melbourne).>