Abstract
Involvement of deep deposits in mining predetermined the trend of development of open pit mining towards increasing the depth of open pits. The main limitation imposed on drilling and blasting in the near-contour zone of an open pit is the need to protect the pit walls and engineering structures on the walls from seismic effects of huge blasts. As practice shows, the most effective and proven method of protecting pit walls is the use of blasting by presplitting method, creation of a shielding gap and a shielding layer of blasted rock mass, i.e. pre-splitting of the pit walls, preceding the huge blast. Therefore, the study of stress-strain state of the near-contour rock mass, determination of the parameters of blastholes for edge pre-splitting (preliminary shielding gap formation) in open pits is an urgent task. The analysis of the pit wall design and stress-strain state of rock mass at Kokpatas deposit exploited by Navoi Mining and Metallurgical Combine allowed to determine the model, as well as the method for calculating stress-strain state of the rock mass. When assessing stability of the pit walls, an approach known as the displacement method was used. Applying the boundary integral equations method allowed to develop an algorithm for calculating stresses in the rock mass for the conditions of Kokpatas deposit. A technique has been developed for experimental studies of blasting contour blasthole charges (blasting by pre-splitting method) using models, allowing to study fracturing on volumetric models and wave interaction by the method of high-speed video recording of the blasting process in transparent models, as well as to determine the parameters of stress waves during blasting in samples of real rocks. A method for formation of stable pit wall slopes, an excavator method for bench pre-splitting on ultimate envelope (contour) of a pit, and a method for initiating blasthole charges in the near contour zone of a pit have been developed and implemented in the industry.
Highlights
Анализ данных по деформации горных пород за контуром массива при производстве массовых взрывов позволил сделать вывод о том, что при подходе к предельному контуру карьера необходимо менять технологию производства буровзрывных работ (БВР) [12,13,14,15]
П. Выбор и обоснование параметров процессов буровзрывных работ для повышения эффективности горно-транспортного оборудования глубоких карьеров: Дис
Summary
При оценке устойчивости бортов карьера использован подход, известный как метод перемещений. Рассмотрим метод граничных интегральных уравнений и алгоритм вычисления напряжений в массиве для условий месторождения Кокпатас. S у составляющие фиктивных нагрузок внутри области S; rx, rу, ‒ x, у компоненты радиуса вектора, проведенного от точки на S к точке в S: Рис. 1. Расчетная схема конструкции бортов и вычисления напряжений в массиве горных пород карьера Кокпатас: n1, n2, ..., nj – нормали к границе области S; S1, S2, ..., Si – длина отрезка границы S; Pвн, Pвн2, ..., Pвнi – внешние нагрузки от отвалов и оборудования, приложенные на длине Lt на расстоянии Lab от края уступа; Fy1, Fy2, ..., Fyi – составляющие силы тяжести в i-й точке области S ν. N j 1 j i b1rx3ij nxi b2rxij b3rx2ijryijnxi ryijnxi b2ry3ij nxi b1rx2ij ryij n yi b2rx3ijnyi b2ry3ijnyi b1rxijry2ijn
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