The Effect of Immediate Strata on Pillar Behavior in Retreat Pillaring-- A Case Study

A. W. Khair,
Organization: International Conference on Ground Control in Mining
Pages: 21
Publication Date: Jan 1, 1986
This paper deals with the analysis of pillar failure in a room and pillar mining operation of a deep underground coal mine. The incident here involved the failure of more than 100 pillars. The mechanism of pillar failure (bump/squeeze) has been studied in detail. The analysis consists of inmine eyewitness observations, laboratory experiments and analytical study of the pillar failure area using finite element technique. Results indicated that the mechanical properties of coal, roof and floor, geologic condition, and the method of operation have affected the mode of pillar failure. Hard roof and floor prevented roof caving and floor heaving in the gob area creating an inhomgeneous stress field on the pillar. This condition developed a yield zone and a core zone in the pillar. Progressive increase of vertical stress further increased the yield zone of the pillar and reduced the core pillar leading to a total squeeze of the pillar. However, the analysis indicated that the pillars were liable to bump provided any sudden shift of load occurred on the core pillar due to some dynamic shock imparted by a local failure of the immediate roof (slickenslided area) or during splitting.
Full Article Download:
(3881 kb)

Additional chapters/articles from the SME-ICGCM book Proceeding of the Fifth Conference on Ground Control in Mining (ICGCM)

Expanded Cement: New Solutions for Age-Old Problems
Determination of Effective Column Lengths for Resin-Grouted
How to Design an Efficient Roof Bolting Plan Based on Simple
Donut Cribbing--A Hew Heavy-Duty Roof Support Concept
Development of A Yielding Steel Post
Design Procedure for Arch Canopies for Rehabilitation of Hig
Investigation of Some Alternatives to Timber Posts and Cribs
Design and Field Testing of a Mobile Roof Support for Retrea
Change in Primary Roof Support System at Quarto Mining Compa
Remote Mining Using Water for Ground Support
New Type of Load Cell for Monitoring of Roof Bolt Tension
Field Measurements of Chain Pillar Response to Longwall Abut
Integrated Instrumentation Method of Stress State, Material
A Study of Roof Caving in the Eastern U.S. Coalfields
A Simple Tool to Measure Stress in Mine Backfill
Optimization of the Stress Control Method to Improve Product
Effect of High Horizontal Stress on Coal Mine Entry Intersec
Analysis of Small-Scale Thrust Faults and Their Effect on Co
A Case History of Computer-Aided Lineament Analysis for Grou
Designing for Upper Seam Stability in Multiple Seam Mining
Behavioral Aspects of Roof/Rib Injuries--Implications for Tr
Engineering Classification of Shales
Empirical Approach to Calculate Rock Loads in Coal Mine Road
Assessment of the Rockburst Proneness in Hard Rock Coal Mine
Outburst Control in Underground Coal Mines,
The Effect of Immediate Strata on Pillar Behavior in Retreat
Roof Control Problems on Development and Longwall Gateroads
A Case Study of Longwall Roof-Supports Interaction
Tailgate Support Evaluation at Plateau Mining Company
Methods of Controlling Hard Roof in a Longwall Face