scholarly journals Evaluation of CAVIJET cavitating jets for deep-hole rock cutting

1981 ◽  
Author(s):  
A.F. Conn ◽  
V.E. Jr. Johnson ◽  
H.L. Liu ◽  
G.S. Frederick
1984 ◽  
Author(s):  
V.E. Jr. Johnson ◽  
W.T. Lindenmuth ◽  
G.L. Chahine ◽  
A.F. Conn ◽  
G.S. Frederick

1982 ◽  
Author(s):  
Virgil E. Johnson ◽  
Georges L. Chahine ◽  
William T. Lindenmuth ◽  
Andrew F. Conn ◽  
Gary S. Frederick ◽  
...  
Keyword(s):  

2019 ◽  
Vol 88 (6) ◽  
pp. 485-488
Author(s):  
Shinji KAWAI ◽  
Takuya NAGAI ◽  
Shigetaka OKANO

1993 ◽  
Vol 63 (2) ◽  
pp. 191-193 ◽  
Author(s):  
K. Ando ◽  
Y. Kawaguchi ◽  
T. Ohno ◽  
A. Ohki ◽  
S. Zembutsu

2021 ◽  
Vol 11 (9) ◽  
pp. 4125
Author(s):  
Zhe Xiang ◽  
Nong Zhang ◽  
Zhengzheng Xie ◽  
Feng Guo ◽  
Chenghao Zhang

The higher strength of a hard roof leads to higher coal pressure during coal mining, especially under extra-thick coal seam conditions. This study addresses the hard roof control problem for extra-thick coal seams using the air return roadway 4106 (AR 4106) of the Wenjiapo Coal Mine as a case study. A new surrounding rock control strategy is proposed, which mainly includes 44 m deep-hole pre-splitting blasting for stress releasing and flexible 4-m-long bolt for roof supporting. Based on the new support scheme, field tests were performed. The results show that roadway support failure in traditional scenarios is caused by insufficient bolt length and extensive rotary subsidence of the long cantilever beam of the hard roof. In the new proposed scheme, flexible 4-m-long bolts are shown to effectively restrain the initial expansion deformation of the top coal. The deflection of the rock beam anchored by the roof foundation are improved. Deep-hole pre-splitting blasting effectively reduces the cantilever distance of the “block B” of the voussoir beam structure. The stress environment of the roadway surrounding rock is optimized and anchorage structure damage is inhibited. The results provide insights regarding the safe control of roadway roofs under extra-thick coal seam conditions.


2021 ◽  
Vol 7 ◽  
pp. 4172-4183
Author(s):  
Shubin Liu ◽  
Hongjian Ni ◽  
Heng Zhang ◽  
Yong Wang ◽  
Ning Li ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 239
Author(s):  
Dmitrij Morozow ◽  
Marek Barlak ◽  
Zbigniew Werner ◽  
Marcin Pisarek ◽  
Piotr Konarski ◽  
...  

The paper is dedicated to the lifetime prolongation of the tools designed for deep-hole drilling. Among available methods, an ion implantation process was used to improve the durability of tungsten carbide (WC)-Co guide pads. Nitrogen fluencies of 3 × 1017 cm−2, 4 × 1017 cm−2 and 5 × 1017 cm−2 were applied, and scanning electron microscope (SEM) observations, energy dispersive spectroscopy (EDS) analyses, X-ray photoelectron spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS) measurements were performed for both nonimplanted and implanted tools. The durability tests of nonimplanted and the modified tools were performed in industrial conditions. The durability of implanted guide pads was above 2.5 times more than nonimplanted ones in the best case, presumably due to the presence of a carbon-rich layer and extremely hard tungsten nitrides. The achieved effect may be attributed to the dissociation of tungsten carbide phase and to the lubrication effect. The latter was due to the presence of pure carbon layer with a thickness of a few dozen nanometers. Notably, this layer was formed at a temperature of 200 °C, much smaller than in previously reported research, which makes the findings even more valuable from economic and environmental perspectives.


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