Stooping Low Safety Factor Pillars At Goedehoop Colliery

Makusha, Gift
Organization: International Conference on Ground Control in Mining
Pages: 6
Publication Date: Jan 1, 2003
The Witbank Coalfield in South Africa contains up to five economically viable coal seams. These seams have been mined continuously for over 100 years and the reserve in now becoming depleted. The normal mining method has been bord and pillar with examples of stooping. The situation now occurs where the formed pillars, left to maintain stability, have a higher quality than the coal that is left in the unmined reserves. Where the reserves are less than 70m deep and continuous over several kilometers, opencast mining is being successfully applied. After several years of investigation, Anglo Coal has identified blocks of coal that warrant investigation with regard to pillar extraction by underground methods The proposed method is pillar extraction using Mobile Roof Supports (MRS) It is proposed to mine three panels at a depth of 120m, by keeping the panels narrow and sub-critical. The sub-critical layout does not allow caving to surface and more stress is thrown onto the barrier pillar rather than the face pillars. The sub-critical span is anticipated to be 100m. The paper describes the full geotechnical investigation, including numerical modelling, instrumentation and drawing on the local South African experience of shortwall mining. The project will be unique in that pillars were not designed for pillar extraction and have low factors of safety (l.4 - 1.8) and width to height ratios of less than 4. The mining height will be approximately 4-4 5m, and this represents "new" operating heights for Mining Roof Supports. The required equipment was ordered in late 2002 and pillar extraction is anticipated to begin in June 2003.
Full Article Download:
(1561 kb)


Additional chapters/articles from the SME-ICGCM book 22nd International Conference on Ground Control in Mining (ICGCM) 22nd

Pillar Design and Roof Support for Controlling Longwall Head
Stress Analysis and Support Design for Longwall Mine-Through
The Utilisation of Numerical Modelling to Predict Water and
Longwall Roof Fall Prediction and Shield Support Recommendat
Comparison Of Multiple And Single Entry Roadways For Highly
Numerical Modeling Of Longwalls In Deep Coal Mines
The Characteristics Of Mining-Induced Fractures In Overlying
Design And Experience Of Total Extraction Room And Pillar Op
Using Site Case Histories Of Multiple Seam Coal Mining To Ad
Mining Method For Extracting An Eight Metre Coal Horizon Con
Stooping Low Safety Factor Pillars At Goedehoop Colliery
Modelling Of Pillar Stability In Room And Pillar Mines
Pillar Optimization For Initial Design And Retreat Recovery
Application Of RMT's Remote Reading Telltale System To
Rock Mechanics Study Of Lateral Destressing For The Advance-
New Tools For Roof Support Evaluation And Design
Considerations For Using Roof Monitors In Underground Limest
Mine Roof Geology Information System (MRGIS)
Imaging Ahead Of Mining With Radio Imaging Method (RIM-IV) I
Geophysics For The Detection Of Abandoned Mine Workings
Investigation Of Seam Thickness And Seam Splitting Within A
Determination Of Rock Strength Properties Using Geophysical
RQD from the Barrel to the Box: Weatherability May be a Bett
A probabilistic approach to ground support design in undergr
The Requirements of a Database to Store Geotechnical Data to
Variation of Horizontal Stresses and Strains in Mines in Bed
Geotechnical Planning Basis for the Optimization of Workings
Tensile roof failure arising from horizontal compressive str
Study of load transfer capacity of bolts using short encapsu
Intersection Stability and Tensioned Bolting
Premature Rock Bolt Failure Through Stress Corrosion Crackin
Short-encapsulation Pull Tests for Roof Bolt Evaluation at a
Field Test with Strain-gauged Friction Bolts at the Gold Hun
Directional Rock Bolt Pullout Tests as Index Tests for Estim
Eclipse Bolting System
The Application of Pre-tensioned Grouted Tendons at Harworth
Investigation into the Extent and Mechanisms of Gloving and
Developments in Improving the Standard of Installation and B
Development of Geotechnical Procedures for the Analysis of M
Recent Developments in the Use of Seismic Tomography in Long
Pumpable Roof Supports: Developing Design Criteria by Measur
Design Considerations of the Secondary Roof Support for Long
The Effect of Standing Support Stiffness on Primary and Seco
Numerical Modeling of the U1A Complex at the Nevada Test Sit
Rock Mechanics and the Analysis of Underground Mine Stabilit
A Study of Potential Fault Reactivation and Water Intrusion
The Elimination of Rock-fall Fatalities in Ontario Hardrock
Root Causes of Groundfall Related Incidents in U.S. Mining I
Analysis on the Dynamics of Mining Subsidence in Range of a
Mitigating Subsidence Influences on Residential Structures C
Influences of Longwall Subsidence on a Guyed Steel Tower - A
Surface Movement of Super-wide Longwall Panels Using Top-coa
New Approach to Evaluate the Stability of Yield Pillars
Experimental Study of Acoustic Emission Characteristics for