The technical details and performance of the newly developed Sandwich spectrometer for ultra low-level gamma-ray spectrometry are presented. The spectrometer, which consists of two HPGe detectors, an active muon shield and a lead/copper shield with a convenient and rapid opening mechanism, is located in an underground laboratory at a depth of 500 m water equivalent. The data is collected in lis...

“resistance literature” is a new term in iranian literature with subject of their islamic revolution and their sacred defense (related to the war iraq imposed iran from 1980 up to 1988). there are many poets who have being worked in this field and their names are listed in relevant books and encyclopedias. this article is to prove that the late farshidvard was one of the pioneer activists again...

1.INTRODUCTION Some forty years ago, most opening supports and reinforcements were designed using empirical rules defining ground loads acting on the supporting structures. This approach is still popular and interest in it has been renewed by the use of rock mass classification systems (Barton et al. 1974, Bieniawski, 1974,1976,1989). Correlations between rock mass conditions and the type of su...

Production scheduling in underground mines is still a manual process, and achieving a truly optimal result through manual scheduling is impossible due to the complexity of the scheduling problems. Among the underground mining methods, sub-level caving is a common mining method with a high production rate for hard rock mining. There are limited studies about long-term production scheduling...

In this research attempts were made to estimate the in-situ stresses acting on a hydrocarbon reservoir based on routine activities of acid injection in oil reservoir. It was found that the relation between the re-opening pressure of fracture and principal in-situ stresses can be estimated using rock mechanics equations for the circular underground cavities. An appropriate relation between the m...

Interpreting observations of seepage into underground openings is often complicated by evaporative potentials created by the necessity to ventilate the openings. Evaporation removes liquid from the seepage face. By doing so, it reduces both the likelihood of seepage onset and the seepage flux, and thus can enhance the perceived effectiveness of the capillary barrier. We modeled liquid-release t...

The authors propose to solve the problems connected with high pressure gradients using a model of linearly elastic body structural parameter. closed finite difference system equations is formulated for plain strain deformation conditions. problem on rock mass in vicinity an underground opening affected by mixed-type gravity-and-tectonic stress field solved. It demonstrated that addition structu...