Results 81 to 90 of about 16,961 (284)

Research of cumulative energy blasting technology with deep and shallow hole combined in hard roof

矿业科学学报, 2020
To solve the problems of low crack rate and large overhanging roof after directional presplitting cumulative blasting technology is implemented under the condition of hard roof, through theoretical analysis, numerical simulation and field monitoring, the
Li Minzu, Ma Zimin, Xue Dingliang, Yuan Yunhai   +3 more
doaj   +1 more source

Analysis of coal pillar rock burst appearance in multi-seam mining with thick and hard roof

, 2022
The existing research only analyzes the rock burst appearance characteristics under specific conditions, lacks research on the rock burst appearance induced by coal pillar under the condition of thick and hard roof. In order to solve this problem, taking
ZHOU Chao, ZHONG Taoping, LI Zhenlei, LI Hongping, LAN Shirui, SONG Dazhao, YANG Wei, ZHANG Chuanjiu   +7 more
core   +1 more source

Re‐evaluation of a soft crested Edmontosaurin, with implications for hadrosaurid life appearance and diversity

The Anatomical Record, EarlyView.
Abstract Hadrosaurid dinosaurs are generally regarded as “crested” or “non‐crested” depending on the presence or absence of a bony cranial crest. At least one supposedly “non‐crested” hadrosaur is known to have possessed a soft tissue cranial crest (or comb), based on an exceptionally preserved “mummified” specimen. Here we redescribe this specimen and
Henry S. Sharpe, Phil R. Bell, Ian Baylatry, Robin Sissons, Corwin Sullivan   +4 more
wiley   +1 more source

Study on pre-splitting blasting technology of hard roof face

IOP Conference Series: Earth and Environmental Science, 2019
Abstract In order to solve the problems of hard roof caving and overhanging area in 220116 working face of Xinji No.2 Coal Mine, deep-hole pre-splitting blasting overburden technology is adopted to destroy the integrity of roof in advance so as to make it collapse as soon as possible, reduce the apparent strength of rock pressure of ...
Huaifu Liu, Zunyu Xu
openaire   +1 more source

The cranial, mandibular, and hyoid anatomy of softshell turtles (Trionychidae): A revised character list for phylogenetic analysis

The Anatomical Record, EarlyView.
Abstract Softshell turtles (Pan‐Trionychidae) are an early branching clade of hidden‐necked turtles (Cryptodira) with a rich fossil record extending back to the Early Cretaceous. The evolutionary history of softshell turtles is still unresolved because of their conservative morphology combined with high levels of polymorphism related to morphological ...
Léa C. Girard, Walter G. Joyce
wiley   +1 more source

Deformation and Fracture Mechanisms of Thick Hard Roofs in Upward Mining Coalfaces: A Mechanical Model and Its Validation

Applied Sciences
The safety and efficiency of underground coal mining are threatened by thick hard roofs characterized by large overhang areas, problematic spontaneous caving, and high dynamic load upon their breakage.
Wei Zhang, Linchao Cao, Dongsheng Zhang, Yang Hu, Jingyu Chang, Zhenying Zhang   +5 more
doaj   +1 more source

Research on the bearing characteristics of brackets in thick hard roof mining sites and the effect of blasting on roof control

Geomechanics and Geophysics for Geo-Energy and Geo-Resources
AbstractDeep mining stress increase and thick hard rock layer endowment drive rock body fissure expansion, leading to sudden fracture of the roof plate accidents. The roof slab of 11,129 working face in Zhangji Mine is a 16 m thick sandstone composite roof slab, whose compressive strength reaches 89.8 MPa.
Jiaxin Dang, Min Tu, Xiangyang Zhang, Qingwei Bu   +3 more
openaire   +2 more sources

Numerical Investigation of Gob-Side Entry Retaining through Precut Overhanging Hard Roof to Control Rockburst

, 2018
Gob-side entry retaining through precut overhanging hard roof (GERPOHR) method is one of the commonly used methods for nonpillar mining. However, feasibility studies of controlling rockburst by this method are few.
Miao Chengyu, Song Peng, He Manchao, Li Gan, Xiaoming Sun, Tang Jianquan, Zhao Chengwei   +6 more
core   +1 more source

Cranial anatomy of a Late Cretaceous aspidorhynchid fish (Neopterygii: Aspidorhynchiformes) from Alberta, Canada

The Anatomical Record, EarlyView.
Abstract Belonostomus longirostrisis was named for an isolated jaw fragment from freshwater Upper Cretaceous (Campanian) sediments of the Dinosaur Park Formation of Alberta, Canada. Following the description of the Albertan species, numerous isolated cranial and postcranial elements have been collected from the Dinosaur Park Formation and assigned to B.
Mondo Miyazato, Luke E. Nelson, Joshua A. Doyon, Donald B. Brinkman, Alison M. Murray   +4 more
wiley   +1 more source

Thick-hard strata movement law and multi-dynamic load mechanism in longwall face with ultra-large cutting height

Meitan xuebao
Large mining height technology is characterized by high yield, high efficiency, and high recovery rate. It has become the preferred technology for mining thick coal seams in Yushen mining area.
Jiachen WANG, Zhaohui WANG, Wenchao SUN, Meng LI, Xin ZHANG, Jialong LI, Dongxin HOU   +6 more
doaj   +1 more source