The movement process and length optimization of deep-hole blasting stemming structure

Author(s):  
Ming Chen ◽  
Zhiwei Ye ◽  
Dong Wei ◽  
Wenbo Lu ◽  
Peng Yan
2020 ◽  
Vol 4 (4) ◽  
Author(s):  
Nurwan Nurwan ◽  
Ali Hadara ◽  
La Batia

ABSTRAK: Inti pokok masalah dalam penelitian ini meliputi latar belakang gerakan sosial masyarakat Kampung Labaluba Desa Kontumere Kecamatan Kabawo Kabupaten Muna, Faktor-faktor yang mendorong gerakan sosial masyarakat Kampung Labaluba Desa Kontumere Kecamatan Kabawo Kabupaten Muna, proses gerakan sosial masyarakat Kampung Labaluba Desa Kontumere Kecamatan Kabawo Kabupaten Muna dan akibat gerakan sosial masyarakat Labaluba Desa Kontumere Kecamatan Kabawo Kabupaten Muna? Latar belakang gerakan sosial masyarakat Kampung Labaluba yaitu keadaan kampungnya yang hanya terdiri dari beberapa kepala keluarga tiap kampung dan jarak yang jauh masing-masing kampung membuat keadaan masyarakatnya sulit untuk berkomnikasi dan tiap kampung hanya terdiri dari lima sampai dengan tujuh kepala keluarga saja. Kampung ini letaknya paling timur pulau Muna terbentang dari ujung kota Raha sekarang sampai kampung Wakuru yang saat ini. Kondisi ini juga yang menjadi salah satu faktor penyebab kampung ini kurang berkembang baik dibidang ekonomi, sosial politik, pendidikan maupun di bidang kebudayaan. Keadaan ini diperparah lagi dengan sifat dan karakter penduduknya yang masih sangat primitif. Faktor yang mendorong adanya gerakan sosial masyarakat Kampung Labaluba Desa Kontumere Kecamatan Kabawo Kabupaten Muna adalah adanya ketidaksesuaian antara keinginan pemerintah setempat dan masyarakat yang mendiami Kampung Labaluba pada waktu itu. Sedangkan proses gerakan sosial masyarakat Kampung Labaluba Desa Kontumere Kecamatan Kabawo Kabupaten Muna bermula ketika pemerintah seolah memaksakan kehendaknya kepada rakyat yang menyebabkan rakyat tidak setuju dengan kebijakan tersebut. Akibat yang ditimbulkan dari adanya gerakan sosial masyarakat Kampung Labaluba Desa Kontumere Kecamatan Kabawo Kabupaten Muna terbagi dua yaitu akibat positif dan akibat negatif.Kata Kunci: Gerakan Sosial, Factor dan Dampaknya ABSTRACT: The main issues in this study include the background of the social movement of Labaluba Village, Kontumere Village, Kabawo Sub-District, Muna District, Factors that encourage social movements of Labaluba Kampung Sub-village, Kontumere Village, Kabawo Sub-District, Muna District, the social movement process of Labaluba Village, Kontumere Village, Kabawo Sub-District Muna Regency and due to Labaluba community social movements Kontumere Village Kabawo District Muna Regency? The background of the Labaluba Kampung community social movement is that the condition of the village consists of only a few heads of households per village and the distance of each village makes it difficult for the community to communicate and each village only consists of five to seven households. This village is located east of the island of Muna stretching from the edge of the city of Raha now to the current village of Wakuru. This condition is also one of the factors causing the village to be less developed in the economic, social political, educational and cultural fields. This situation is made worse by the very primitive nature and character of the population. The factor that motivated the existence of the social movement of Labaluba Village in Kontumere Village, Kabawo Subdistrict, Muna Regency was the mismatch between the wishes of the local government and the people who inhabited Labaluba Village at that time. While the process of social movements in Labaluba Village, Kontumere Village, Kabawo District, Muna Regency began when the government seemed to impose its will on the people, causing the people to disagree with the policy. The consequences arising from the existence of social movements in Labaluba Village, Kontumere Village, Kabawo District, Muna Regency are divided into two, namely positive and negative effects. Keywords: Social Movements, Factors and their Impacts


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.


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.


2020 ◽  
Vol 87 (12) ◽  
pp. 757-767
Author(s):  
Robert Wegert ◽  
Vinzenz Guski ◽  
Hans-Christian Möhring ◽  
Siegfried Schmauder

AbstractThe surface quality and the subsurface properties such as hardness, residual stresses and grain size of a drill hole are dependent on the cutting parameters of the single lip deep hole drilling process and therefore on the thermomechanical as-is state in the cutting zone and in the contact zone between the guide pads and the drill hole surface. In this contribution, the main objectives are the in-process measurement of the thermal as-is state in the subsurface of a drilling hole by means of thermocouples as well as the feed force and drilling torque evaluation. FE simulation results to verify the investigations and to predict the thermomechanical conditions in the cutting zone are presented as well. The work is part of an interdisciplinary research project in the framework of the priority program “Surface Conditioning in Machining Processes” (SPP 2086) of the German Research Foundation (DFG).This contribution provides an overview of the effects of cutting parameters, cooling lubrication and including wear on the thermal conditions in the subsurface and mechanical loads during this machining process. At first, a test set up for the in-process temperature measurement will be presented with the execution as well as the analysis of the resulting temperature, feed force and drilling torque during drilling a 42CrMo4 steel. Furthermore, the results of process simulations and the validation of this applied FE approach with measured quantities are presented.


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