Relationship between Two Consecutive Slope Failures at Elbistan Open Cast Mine


Unver B., Hindistan M. A.

16th International Symposium on Environmental Issues and Waste Management in Energy and Mineral Production (SWEMP) / International Symposium on Computer Applications (CAMI), İstanbul, Turkey, 5 - 07 October 2016 identifier

  • Publication Type: Conference Paper / Full Text
  • City: İstanbul
  • Country: Turkey
  • Keywords: Elbistan, Collolar, gyttja, slope failure, open cast
  • Hacettepe University Affiliated: Yes

Abstract

Two consecutive slope failure disasters took place at Elbistan Collolar open cast mine in 2011. The box cut had been excavated for 3 years during the time of slope failures. Signs of slope instability such as tension cracks and considerable upward movement at the toe have been realized at the permanent South-West slope after 2 years of operation in January 2010. By means of dumping at the toe and decreasing the weight of the block initiating sliding at the slope top, movement on the slope was controlled and stopped for about during summer season. Displacements on the slope started once again in January 2011 and could not be controlled leading to slope failure on the permanent SW slope on February 6th 2011. There was one fatality in this failure. Stress release on the bottom of the pit totally changed the stress regime. The difference between major and minor principal stresses was increased. The material at the pit bottom was sandwiched by stresses exerted by both counter facing slopes. Once the slope failure at the SW slope has taken place, there was a stress relief at the toe of SW slope. This phenomenon has changed the stress state at the pit bottom. The bottom was stress by NE slope, however, after failure at SW slope the counter stress was almost lost. Consequently, there must have been significant horizontal movement at NE slope toe region in the form of a creep movement. As a result of the horizontal movement at the pit bottom, NE slope lost its integrity and a sudden slope failure much bigger than the first one took place on February 10th 2010 about 4.5 days later than the first slope failure. There were 10 fatalities in the second slope failure. This paper mainly focuses on the relationship between the failures.