Defined by international telecommunications union (ITU), the spectrum in the band between 30 and 300 Hz are named as super low frequency (SLF). In this band, the electromagnetic waves are rarely shielded by strata of lower resistivity and can spread strongly. Therefore, it can be used on the earth’s surface to detect goaves underground. The equipment, which use the natural SLF electromagnetic s...

By a Computational Fluid Dynamics software named Fluent, the influence that the permeability, gas emission intensity of goaf and turbulent parameters in working face have on the numerical simulation was studied. The results show that: the permeability and gas emission intensity of goaf have great influence on the migration law of gas and goaf air leakage, causing great impact on the gas concent...

Multiresolution analyses based on wavelets and support vector machine were combined to establish a wavelet transform-based support vector machine (WT-SVM) model for the prediction of residual settlement in an old goaf. The stochastic volatility of the residual settlement in an old goaf is considered, and the test data of 3 monitoring point in an old goaf in Yanzhou are used. The results are com...

fundamental understanding of the goaf gas distribution in a gassy coal mine is necessary for developing effective goaf gas drainage strategies in the longwall coal mine. the goaf gas was subjected to the surface and body forces that were classified depending upon whether they acted on the surface area or the volume of the gas element. of these forces, the body forces were more predominant in di...

Fundamental understanding of the goaf gas distribution in a gassy coal mine is necessary for developing effective goaf gas drainage strategies in the longwall coal mine. The goaf gas was subjected to the surface and body forces that were classified depending upon whether they acted on the surface area or the volume of the gas element. Of these forces, the body forces were more predominant in di...

Effective gas management is vital to the success of the longwall mining in the Bulli seam, in the Southern Coalfield, Sydney Basin, NSW, Australia. The evolution of gas drainage methods and practices are discussed with respect to gas type, gas drainage lead time and prevailing geological conditions. Both underground to inseam drilling and surface to inseam drilling techniques are described at b...

The shape measurement of goaf is an important job in mine project. With the rapid development of the measuring equipment, 3D laser scanner, which makes the efficiency of traditional work being improved, is widely used in goaf. The final result of 3D laser scan is a huge collection of points. Although different measuring intervals will lead different point cloud density, it also needs a large st...

It is necessary to obtain a fundamental understanding of the goaf gas flow patterns in longwall mine in order to develop optimum goaf gas drainage and spontaneous combustion (sponcom) management strategies. The best ventilation layout for a longwall underground mine should assist in goaf gas drainage and further reduce the risk of sponcom in the goaf. Further, in the longwall panel, regulators ...

Local features are usually used to describe pedestrian appearance. While most of existing pedestrian detection methods don’t make full use of context cues, such as associated relationships between local different locations. This paper proposes two novel kinds of local associated features, gradient orientation associated feature (GOAF) and local difference of ACF (ACF-LD), to exploit context inf...

Goaf restoration is an important part of urban space management. With mining coal resources, appearance goaf and subsidence areas causes serious geological disasters environmental ecological problems, which significantly affect safety, development, construction. Therefore, repair goafs crucial. In this study, the Jingmen Garden Expo Park was taken as example. Through acquisition engineering con...