The instability of extraction structure under the undercut space in block caving stope presents specific characteristics: rib spalling and floor heave ore-loading roadway collapse major apexes. In order to study stress displacement evolution law reveal mechanism structure, numerical simulation model was established using finite difference software FLAC3D. According postundercutting strategy Ton...

The evolution of surface subsidence is an important focus of study above Molycorp, Inc.’s newest block cave at the Questa molybdenum mine near Taos, New Mexico. The case study compares mature glory hole subsidence over the Goathill Orebody and subsidence emerging in its earliest stage over the new D Orebody block cave. Subsidence above the D Orebody was first detected in April 2003, 30 months a...

The three-dimensional cuboids packing is NP-hard and finds many applications in the transportation industry. The problem is to pack a subset of cuboid boxes into a big cuboid container such that the total volume of the packed boxes is maximized. The boxes have no orientation constraints, i.e. they can be rotated by 90◦ in any direction. A new heuristic algorithm is presented that defines a conc...

A fracture expansion criterion of hydraulic fracturing was suggested to deal with the hard and stable roof control in coal mines. An experiment designed for control, reliability model verified. Four different types holes technology were setup room, a fully mechanized caving face implemented.

Determining the caving height in block method requires considering a suitable criterion discussed this study. The comparison between different criteria and choosing appropriate for use rock mass cavability study is main idea of study, which has not been investigated previous studies. In paper, through FEM (Finite Element Method) software, area undercutting stages was calculated using displaceme...

Metal mines mined using the sublevel caving method often exhibit various environmental problems on ground surface. This can affect safety of production process in mining area. A numerical model Universal Distinct Element Code has been established to investigate deformation failure giving rise this underground mining. The calculations are combined with in-situ monitoring data collected over a pe...

Purpose. Determining the actual dimensions of protecting and crown pillars ore bodies by seismic survey assessing possibility rock mass collapse fracturing at lower levels Zhairemskoye field. Methods. An integrated approach is used, which involves analysis complete development during combined mining. To determine geological strength index (GSI) rating (RMR), structure studied, as well executed ...

The valence state of UTe$_2$ was studied by core-level photoelectron spectroscopy. main peak position the U $4f$ spectrum coincides with that UB$_2$, which is an itinerant compound a nearly $5f^3$ configuration. However, broader than and satellite structures are observed in higher binding energy side peak, characteristics mixed-valence uranium compounds. These results suggest 5$f$ mixed dominan...