Eremenko, AA, Serakov, VM, Filatov, AP, Eremenko, VA & Serakov, AV 2007, 'Estimate of the Rock Mass Stress State in the Course of Underground Mining of the Kimberlite Deposit', in Y Potvin (ed.), Deep Mining 2007: Proceedings of the Fourth International Seminar on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 493-498, https://doi.org/10.36487/ACG_repo/711_36 (https://papers.acg.uwa.edu.au/p/711_36_Eremenko/) Abstract: The paper presents a study into the geomechanical state of rock masses in the area where the kimberlite pipe “Udachnaya” is being developed, Yakutsky diamondiferous region. The unique feature of mining operations here is the division of the orebody into two pipes at a depth of 250 m, from where the pipes are mined separately. Of particular interest is the analysis of stress fields in the most characteristic phases of mining: on completion of quarrying for a depth of 600 m, and during the first and second stage mining of the reserves subjacent to the quarry bottom for a depth of 600 m. For each stage of mining, we have determined the zones of compressive and tensile stresses, dynamics of change in geometry of the zones and in the stress values within the zones when mining is carried out with application of various winning techniques for the quarry subbottom reserves. Assessment of the stability of the quarry walls is performed, and the values of safety factor are obtained for potential slip lines when under further development of open pit and underground mining. The grounds have been given for the efficient and safe alternative methods that are recommended for the use in the course of underground mining at a kimberlite deposit.