When mining ore bodies in Kryvyi Rih iron basin, underground mines apply open stoping or bulk caving systems proportion of 55% to 45%. Most prefer with pillar caving. Yet, rock pressure contributes growth costs for workings maintenance and deterioration extraction indices. Rock mass indices can be enhanced by application a protectve structure the upper part block that will enable additional dec...

Many proposals of pseudorandom sequence generators and stream ciphers employ linear feedback shift registers with dynamic feedback (DLFSR) as the main module to increase the period and linear span of the involved msequences. In this paper, we present a theoretical model that allows the design of longer sequences with higher linear span than in previous DLFSR schemes. The model determines the co...

During the mining process of fully-mechanized caving faces, roof roadway behind working face easily forms an arched-shape hanging structure with pushed forward, which results in potential hazards such as gas accumulation and large-scale collapse. Based on actual situation a at difficult end top coal through borehole exploration, surrounding rock displacement observation, bolt stress monitoring,...

The main goal of this work is to find a spread PG(3,13). By construct complete span which represents applications algebraic geometry in 3-dimensional projective space PG(3,q). We prove that the maximum (Ƙ,b)-span PG(3,13) (170,b)-sp -span, spread.

The perceptual span or region of effective vision during eye fixations in reading was examined as a function of reading speed (fast readers were compared with slow readers), font characteristics (fixed width vs. proportional width), and intraword spacing (normal or reduced). The main findings were that fast readers (reading at about 330 wpm) had a larger perceptual span than did slow readers (r...

We present some fixed point results for a single mapping and a pair of compatible mappings via auxiliary functions which satisfy a generalized weakly contractive condition in partially ordered complete $G$-metric spaces. Some examples are furnished to illustrate the useability of our main results. At the end, an application is presented to the study of exi...

background : the aim of the present study was to assess the auditory working memory span of children with (central) auditory processing disorders (c) apd aged 8 to 10 years and to compare the results with normal ones. methods: twenty five children with (central) auditory processing disorders (8-10 years) and 75 normal children (8-10 years) from both genders participated in this comparative stud...

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...