In view of the deformation and instability law hard roof without side filling retaining roadway, based on systematic construction analysis force bearing model roadway structure, this article proposes control mechanical calculation method retaining, which takes anchor beam key block above to form cantilever together, with solid coal as foundation support. The research practice show that under co...

This paper presents a collaborative control scheme involving “unloading-solidifying” to prevent rock bursts during narrow pillar recovery at large mining depths. In this study, the stress distribution rule of coal mass excavation and process is studied, energy accumulation characteristics overlying hard thick roof structure are investigated. way, burst inducing mechanism working face under comp...

To study the deformation and failure mechanisms of soft rock mining roadways, 1506 return airway Anyang Coal Mine is taken as engineering background. Based on limit analysis theory, a model based rigid slider system constructed to assess surrounding roadway. The formulas for calculating self-weight power in velocity discontinuity line roadway, work pressure, energy dissipation rate are derived,...

Mine roof fall characteristics of 250 falls in 5 different room-and-pillar coal mines, located in Pike, Martin, and Floyd counties, Kentucky, were investigated to determine the relationship of selected parameters associated with roof failure and the assumed condition of the mine roof before failure. The selected parameters used in the study included: presence of cracks and water before the occu...

Gob-side entry retaining formed by roof fracturing (GERRF) is a popular non-pillar mining method. The method uses crushed rocks in gob side to support and control the movements of roof. These will deform under pressure generate desirable lateral stress on structures gangue rib. In this study, deformation behavior mudstones with different particle sizes incremental loading was investigated an in...

This paper presents the analytical solution of groundwater response to tidal fluctuation in a coastal multilayer aquifer system consisting of a leaky confined aquifer, a semipermeable layer, and an unconfined aquifer. The semipermeable layer, or the roof of the leaky confined aquifer, extends under the sea. Comparisons are made with solutions derived previously, which considered only a single a...

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...

The roof plate is an organizing center in the dorsal CNS that controls specification and differentiation of adjacent neurons through secretion of the BMP and WNT signaling molecules. Lmx1a, a member of the LIM-homeodomain (LIM-HD) transcription factor family, is expressed in the roof plate and its progenitors at all axial levels of the CNS and is necessary and sufficient for roof plate formatio...

The paper describes a novel approach for the generation of 3D building models from airborne laserscanner data, which is based on the detection of straight lines in specific 2D projections of the data. First, the main roof ridge directions of a building are determined. Based on these ridge directions, hypotheses on the roof orientation are generated. The whole point cloud is rotated by the roof ...

Photovoltaic (PV) panels get hot in the sun. This decreases the operating efficiency through various means. Several approaches have been proven effective at cooling panels. Green Roofs are thermally cool, outperforming even white roofs over their life. On a hot summer day, a green roof can be 30◦C cooler than a typical roof, potentially improving the efficiency of a photovoltaic (PV) panel by a...