DBPapers

ASSESSMENT OF MOISTURE EFFECT ON ROOF ROCK BEHAVIOUR IN EAST ALBORZ COAL MINES

AUTHOR/S: M. JAVANSHIR, M. ATAEI, S. R. TORABI
Sunday 1 August 2010 by Libadmin2008

8th International Scientific Conference - SGEM2008, www.sgem.org, SGEM2008 Conference Proceedings/ ISBN: 954-918181-2, June 16-20, 2008, Vol. 1, 377-384 pp

ABSTRACT

Roof falls continue to be one of the greatest hazards faced by underground coal miners.
For preventing unpredictable hazards and losses due to roof falls, assessment of roof
rock behaviour in coal mines plays an assential role in ground control issue. However,
based on the intensive reserches in this area, various parameters influence the roof rock
behaviour of the stratified rock mass. One of them, which is extremely important to coal
mine ground control, is moisture sensitivity. Many coal seams have immediate roofs
with moisture sensitivite and weak shale compositions. presence of moisture sensitivite
mudrocks can cause ground control problems. They can severly damage the roof by
reducing rock strength, and generating swelling pressures. Therfore, in roof rock
assessment, moisture sensitivity is the factor, which must be assessed carfully and with
high accuracy. Although slake durability test (SDT) has been widely used to evaluate
moisture sensitivity of mudrocks, this method is a labratory test and is a time consuming
method. Furthermore in this method, rock samples must be carefully wrapped to
maintain in situ moisture content. Therfore, determination of an index that can easily
measure this parameter in situ and with high accuracy has great importance. Immersion
test is A simple method which can easily determine this index. In this research, to
compare the slake durability and immersion test and establish the relationship between
the two tests, rock samples were collected from various mines of East Alborz coalfield.
These samples tested with two methods. According to these analyses, a high correlation
was found between the two tests.

Keywords: coal mine, roof rock, ground control, moisture sensitivity, slake durability test, immersion test.