Annual Report,2009 - Directorate General of Mines Safety

DGMS Annual Report, 2009
During the scrutiny of those circulars in this Directorate while recording, it
was found that there were certain typographical errors and mistakes which
have been rectified and corrected.
The corrected Circulars have now been issued with the same Circulars
Numbers, therefore the Circulars issued earlier (Circular No. 9 of 2008 issued
on 02.12.2008 and Circular No. 1 of 2009 issued on 16.01.2009) may kindly
be replaced with these issued on 18 th February 2009.
Inconvenience caused is deeply regretted.
No. DGMS (Tech)/Circular No./ 06 of 2009 Dhanbad, Dated – 12/03/2009
To,
Owner/Agent/Manager of all coal Mines.
Sub:- Use of Local Methane Detector (LMD) in underground Coal Mines.
Firedamp or Methane is the most important of the mine gases and has caused
more loss of life in mines than any other gas. Methane or firedamp are synonymous to
each other. Firedamp is a mixture of inflammable gases emitted from strata and
besides methane, which is the principal constituent of mixture, contains higher
hydrocarbons, carbon dioxide, nitrogen and water vapour. Methane mixed with air in
certain proportions forms explosive mixtures. The approximate lower and upper limits
of flammability of methane air mixtures are 5 and 14.8% of CH 4 . Firedamp
explosions have been responsible for deaths of many miners throughout the history of
mining. Statistical figure indicated that during the period 1901 to 2007 there had been
37 cases of explosion (major accidents/disaster) resulting in death of 1258 persons.
Lots of emphasis were given since then in detection and measurement of CH 4
concentration in mine atmosphere. Methane emission at a face is affected by factors
such as type of work going on at the face and machinery used, the time of observation
in relation to the cycle of work at face, the rate of coal output and face advance,
barometric pressure change, variation in air velocity., method of mining and roof
control and geological factors. Sudden emission of methane may occur as
instantaneous coal and gas outburst, sudden emission from roof or floor strata, as gas
blower from the coal seam or adjacent strata. Thus, every mine having potential
hazard on methane emission should have methane monitoring system installed and
maintained.
that –
(i)
(ii)
In this connection Regulation 145(1)(e) of Coal Mines Regulation 1957 says
If the determination of inflammable gas in any ventilating district shows the
percentage of inflammable gas to exceed 1.25 percent, the supply of electric
energy shall be cut-off immediately from all cables and apparatus working in
the district.
Again, Rule 126(4)(d) of Indian Electricity Rules, 1956 says that in any coal
seam of second or third degree gassiness or in the danger zone of oil mines :-
167