Kazakhmys Corporation, Zhezkazgan, Republic of Kazakhstan:

A. B. Makarov, Geomechanics Expert, Professor, Doctor of Engineering Sciences, abm51@mail.ru
D. V. Mosyakin, Chief Geomechanics Engineer for Zhezkazgan Region

Eastern Mining and Metallurgical Research Institute for Non-Ferrous Metals – VNIITsvetmet, Ust-Kamenogorsk, Republic of Kazakhstan:

A. I. Ananin, Deputy Director, Candidate of Engineering Sciences

The article discusses the current issues of subsidence, weakening and sinking of ground surface above underground mining of blind ore bodies using caving. The simplest geometrical relations based on the analysis of the practical mining experience are used to estimate conditions of backfill of voids and strata subsidence up to the ground surface and to estimate the depth of the resultant sink. It is proved that the key parameter for evaluation of a geomechanical process mechanism is the coefficient of rock weakening under failure. Based on the in-situ measurements and the work-back calculation, the authors obtain regular patterns of weakening coefficient distribution in terms of Ridder–Sokol and Zhezkazgan deposits. It is suggested to introduce the described criteria of caving in the new edition of Guidelines for Protection of Structures from Harmful Effects of Mining.

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