Skip to main content
Log in

Coal Mine Roadway Stability in Soft Rock: A Case Study

  • Original Paper
  • Published:
Rock Mechanics and Rock Engineering Aims and scope Submit manuscript

Abstract

Roadway instability has always been a major concern in deep underground coal mines where the surrounding rock strata and coal seams are weak and the in situ stresses are high. Under the high overburden and tectonic stresses, roadways could collapse or experience excessive deformation, which not only endangers mining personnel but could also reduce the functionality of the roadway and halt production. This paper describes a case study on the stability of roadways in an underground coal mine in Shanxi Province, China. The mine was using a longwall method to extract coal at a depth of approximately 350 m. Both the coal seam and surrounding rock strata were extremely weak and vulnerable to weathering. Large roadway deformation and severe roadway instabilities had been experienced in the past, hence, an investigation of the roadway failure mechanism and new support designs were needed. This study started with an in situ stress measurement programme to determine the stress orientation and magnitude in the mine. It was found that the major horizontal stress was more than twice the vertical stress in the East–West direction, perpendicular to the gateroads of the longwall panel. The high horizontal stresses and low strength of coal and surrounding rock strata were the main causes of roadway instabilities. Detailed numerical modeling was conducted to evaluate the roadway stability and deformation under different roof support scenarios. Based on the modeling results, a new roadway support design was proposed, which included an optimal cable/bolt arrangement, full length grouting, and high pre-tensioning of bolts and cables. It was expected the new design could reduce the roadway deformation by 50 %. A field experiment using the new support design was carried out by the mine in a 100 m long roadway section. Detailed extensometry and stress monitorings were conducted in the experimental roadway section as well as sections using the old support design. The experimental section produced a much better roadway profile than the previous roadway sections. The monitoring data indicated that the roadway deformation in the experimental section was at least 40–50 % less than the previous sections. This case study demonstrated that through careful investigation and optimal support design, roadway stability in soft rock conditions can be significantly improved.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15

Similar content being viewed by others

References

  • Bauer ER, Dolinar DR (2000) Skin failure of roof and rib and support techniques in underground coal mines. In: New technology for coal mine roof support. NIOSH information circular, pp 99–109

  • Chase F, Mark C, Heasley K (2002) Deep cover pillar extraction in the US coalfields. In: 21st International conference on ground control in mining, Morgantown, 6–8 August, pp 68–75

  • Chen J, Mishra M, Zahl E, Dunford J, Thompson R (2002) Longwall mining-induced abutment loads and their impacts on pillar and entry stability. In: 21st International conference on ground control in mining, Morgantown, 6–8 August, pp 11–17

  • Dolinar DR, Mucho TP, Oyler DC, Pablic J (2000) Utilising the ‘‘advanced and relieve’’ method to reduce horizontal stress effects on the mine roof, a case study. In: 19th International conference on ground control in mining, Morgantown, 8–10 August, pp 137–48

  • Heidarieh-Zadeh AM, Smith SF (1985) Stability behaviour of deep level coal mining tunnels. Min Sci Technol 2(3):171–179

    Article  Google Scholar 

  • Hudewentz DFC, Lucker AHF (1983) Modern tunneling technology in deep German coal mines under difficult ground conditions. In: Proceedings of 6th Rapid Excavation and Tunneling Conference, Chicago, 12–16 June 1983. AIME, New York, pp 910–924

  • Itasca (2004) UDEC—universal distinct element code. Itasca Consulting Group Inc., Minneapolis

    Google Scholar 

  • Oggeri C (2000) Design methods and monitoring in ornamental stone underground quarrying. GeoEng 2:151

    Google Scholar 

  • Seedsman R (2001) The stress and failure paths followed by coal mine roofs during longwall extraction and implications to tailgate support. In: 20th International conference on ground control in mining, Morgantown, pp 42–49

  • Shen B, King A, Guo H (2008) Displacement, stress and seismicity in roadway roofs during mining induced failure. Int J Rock Mech Min Sci 45:672–688

    Article  Google Scholar 

  • Shepherd J, Lewandowski T (1993) Instrumentation of roof support for colliery pillar extraction. In: Szwedzicki T (ed) Geotechnical instrumentation and monitoring in open pit and underground mining, pp 409–516

  • Tadolini SC, Kraus PW, Worbois A (2000) High capacity tensioned cable bolts for tailgates support. In: 19th International conference on ground control in mining, Morgantown, 8–10 August, pp 59–66

  • Tiandi Science and Technology Ltd. (2005) Mining method investigation and design for Zijin Mine of Fenxi Group. Report by Department of Mining Engineering, Tiandi Science and Technology Ltd, December 2005 (in Chinese)

  • van der Merwe JN, van Vuuren JJ, Butcher R, Canbulat I (2001) Causes of falls of roof in South African collieries. Safety in mines research advisory committee (SIMRAC). Final project report, report no. COL613

  • Whittaker BN, Singh RN (1981) Stability of longwall mining gate roadways in relation to rib pillar size. Int J Rock Mech Min Sci Geomech Abstr 18:331–334

    Article  Google Scholar 

  • Wu L, Cui C, Geng N, Wang J (2000) Remote sensing rock mechanics (RSRM) and associated experimental studies. Int J Rock Mech Min Sci 37:879–888

    Article  Google Scholar 

  • Zahl E, Dunford J, Larson M, Brady T, Chen J (2002) Stress measurements for safety decisions in longwall coal mines. In: 21st International conference on ground control in mining, Morgantown, 6–8 August, pp 45–52

  • Zhang Y, Peng S (2002) Design considerations for tensioned bolts. In: 21st International conference on ground control in mining, Morgantown, 6–8 August, pp 131–140

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Baotang Shen.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Shen, B. Coal Mine Roadway Stability in Soft Rock: A Case Study. Rock Mech Rock Eng 47, 2225–2238 (2014). https://doi.org/10.1007/s00603-013-0528-y

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00603-013-0528-y

Keywords

Navigation