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Impact of longwall mining on slope stability – A case study Cover

Impact of longwall mining on slope stability – A case study

Open Access
|Nov 2022

Figures & Tables

Figure 1

Location of the Cao Son open pit coal mine [37].

Figure 2

Exploitation plan in the region of Cao Son and Khe Cham II–IV in the North–South cross section (A–A′).

Figure 3

Fragmental lithology and distribution of rock mass at the site study.

Figure 4

Simplified 2D model geometry.

Figure 5

Calculation variants due to pit slope stages and monitoring points on the slope surface.

Figure 6

Pit slope in 2025: (a) scheduled geometry, (b) FoS contours and slope failure surfaces.

Figure 7

Pit slope in 2030: (a) scheduled geometry, (b) FoS contours and slope failure surfaces.

Figure 8

Failure zone induced by UG operation by 2025: (a) scenario I, (b) scenario II, (c) scenario III

Figure 9

FoS values for defferent scenarios of UG operation by 2025: (a) scenario I, (b) scenario II, (c) scenario III.

Figure 10

Failure zone induced by UG operation by 2030: (a) scenario IV, (b) scenario V.

Change of FoS value and size of the slope failure surface with different scenarios of UG operation by 2025_

Slope in 2025FoS valueSize of the slope failure surface

Before UGAfter UG

Scenario IScenario IIScenario III
Left slope wall1.75–2.01.75–2.0Increased1.5–1.75Increased1.75–2.0-
Right slope wall>2.5>2.5->2.5-2.0–2.25Increased

Mechanical properties of rock mass in the studied region [33]_

Type of rock massBulk modulus K (GPa)Shear modulus G (GPa)Cohesion c (MPa)Fiction angle φ (°)Tensile strength σt (MPa)Density ρ (kg/m3)
Mudstone2.311.541.87301.342620
Claystone2.231.342.05261.142600
Anthracite2.171.362.14271.221500
Conglomerate4.763.573.23282.272510
Sandstone3.912.463.56281.962600

Strength parameters of the fault in the studied region [33]_

Strength parametersFriction angle (°)Cohesion (kPa)Tensile strength (kPa)
Value12–203.4–4.40

Hypotheses for calculating thickness of the caved zone_

Author, yearThickness of caved zone
Peng and Chiang, 1984 [38](2–10)t
Bai et al., 1995 [39]100t/(c1g+c2)
Mazurkiewicz et al., 1997 [40]t/(kr−1)
Heasley, 2004 [41](10–18)t
Biliński, 2005 (simplified) [42](nkst)/(0.05Rc0.5+0.02)
Wang et al., 2017 [43](3–4)t
DOI: https://doi.org/10.2478/sgem-2022-0019 | Journal eISSN: 2083-831X | Journal ISSN: 0137-6365
Language: English
Page range: 282 - 295
Submitted on: Oct 28, 2020
Accepted on: Aug 30, 2022
Published on: Nov 27, 2022
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year

© 2022 Phu Minh Vuong Nguyen, published by Wroclaw University of Science and Technology
This work is licensed under the Creative Commons Attribution 4.0 License.