The rectangle packing problem often appears in encasement and cutting as well as very large-scale integration design. To solve this problem, many algorithms such as genetic algorithm, simulated annealing and other heuristic algorithms have been proposed. In this paper, a new heuristic algorithm is recommended based on two important concepts, namely, the corner-occupying action and caving degree...

LKAB’s Kiruna Mine, located in northern Sweden, produces about 24 million tons of iron ore yearly using an underground mining method known as sublevel caving. To efficiently run the mills that process the iron ore, the mine must deliver planned quantities of three ore types. We used mixed-integer programming to schedule Kiruna’s operations, specifically, which production blocks to mine and when...

Abstract Mining advances to greater depth, where the control of rock pressure is central for a successful operation. To handle increasing at LKAB’s Kiruna iron ore mine, LKAB and Montanuniversität Leoben develop novel mining method called “raise caving”. Raise caving based on an active stress management approach. De-stressing slots, which are separated by substantial pillars, developed first pr...

Large deformations that accompany longwall mining result in complex spatial and temporal distributions of changes in undrained pore ̄uid pressures around the advancing face. These seemingly anomalous changes are recorded in the rapid water level response of undermined and adjacent wells, and may be explained in the short-term as a undrained poroelastic e€ect. A three-dimensional ®nite element mo...

This paper presents the engineering geological properties and roof control tecnology for a thick coal seam fully-mechanized face mining with hard roof conditions (THC) at the Jinhuagong Coal Mine (JCM), northwest China. The effective support working resistance and appropriate roof control technology are two critical factors for safe and productive mining in the THC. The load-estimate-method (LO...

Psychophysical two-tone suppression was measured in three normal-hcaring young adults using the pulsation-threshold technique. The primary objective was to study the effect of L• on psychophysical twotone suppression for f2/f• > 1.0. Measurements were obtained at low and mid frequencies and for input levels ranging from 40 through 85 dB SPL. For f• --1000 or 2000 Hz, suppression i creased initi...

To study on the characteristics of the vibration signals of coal and stone hitting the armor plate during caving, a hybrid algorithm based on first order forward difference and wavelet transform modulusmaxima method is presented which can be used in the longwall top coal face. First, in order to reduce the noise interference, the pre-processing of the vibration signals is done by the first orde...

Abstract In the process of longwall top coal caving, selection caving interval along advancing direction working face has an important effect on recovery. To explore a realistic face, panel 8202 in Tongxin Coal Mine is used as example, and 30 numerical simulation models are established by using Continuum-based Distinct Element Method software to study recovery with 4.0 m, 8.0 12.0 16.0 20.0 m 2...

The underground space of the Kupol deposit is analyzed as a multicomponent system – rocks, water, microbiota, gases (including mine atmosphere) and supporting structures metal support shotcrete (as an additional type barring) also stowing materials. complex host rocks highly disintegrated due to active tectonic volcanic activity in Cretaceous period. thickness sub-permafrost reaches 250-300 m. ...