Presentation Outline
Introduction
CASE STUDY: recent flammable
Purpose of Accident Investigations
gas explosions in South African
Case Studies Conclusions, Recommendations
hard rock mines
Brief Analysis of case studies
Relevant outcomes of GAP 504
IOHA 2005  South Africa
Guidelines on Explosion Prevention
Vijay Nundlall
Criteria for the Declaration of hazardous
Department of Minerals and Energy
Locations
Introduction Introduction
Components of a
The significance of Flammable Gas
Flammable Gas
Explosions:
Explosion:
Oxygen  part of mine
The loss of Life
air
Fuel  is the methane in Breach of Legislation  Systems failures
an explosive range
Loss of Production, Material and
Ignition source
Equipment
NB: All three
components must be
Duty of Care by employer not fulfilled
present for the
explosion to occur!
Purpose of Accident Investigations Case Studies
To establish the underlying causes of an The last three major
flammable gas
accident that results in a fatality.
explosions - in terms of
Following the investigation a written report -
the conclusions of the
in terms of Section 64(1) & (2) of the MHS Act
investigation and inquiry
must be prepared of the findings, and any
reports and the
remedial steps that may be required
recommendations
To establish system failures that has led to
and/or remedial actions
the disaster and to purposely steer away from
that were suggested.
the apportioning of blame.
1
Mponeng 1999 Mponeng 1999-conclusions
99 Level RAW 106m
West The investigation concluded that the
No. 8 No.7
No. 9 No. 6
99 Level
explosion that occurred was as the
Haulage West
result of an ignition of the flammable
Diamond drill hole site
gas released into the general
196m
290m
atmosphere by the drilling of a cover
99-46 Crosscut S
99-44 Crosscut S
99-42 Crosscut
hole and dispersed in the section by the
S
ventilation system.
99-44 Raise
This event resulted in the death of 19 mine workers
Mponeng 1999-conclusions Mponeng 1999-conclusions
With respect to the detection of flammable
The gas emission could not be controlled
gas at this site-the mine s system governing
since the drilling equipment was not designed
the issuing of FGMI s was not effective.
to shut off gas emissions.
The reaction and the apparent lack of
The re-circulating semi-series ventilation
response by the workforce indicate
system in use at the time generated
shortcomings in emergency evacuation
progressive contamination of ends in the
training.
section.
The baseline risk assessment done for this
A number of deviations from procedures
section was not comprehensive and some of
regarding ventilation standards its recommendations were not implemented
Mponeng 1999-recommendations
Mponeng 1999-recommendations
Training programmes to be revised with
respect to : Evacuation procedures ,
All rigs used for cover drilling should be
elevating the awareness of all employees on
capable of immediately shutting off an inflow
the dangers of flammable gas explosions,
of water and/or gas  New technology exists
flammable gas testing procedures
to address this issue.
Appropriate issue-based risk assessments
Local re-circulation of air should be avoided
should be structured for all development ends
at all times.
highlighting aspects regarding use of
Stricter shift control systems must be put into
specialised mining equipment, air flow,
place to ensure that all designated users are
contamination, detection, dilution,
issued with instrumentation (FGMIs), prior to
precautionary measures, communication and
proceeding underground
safe evacuation practices.
2
Mponeng 1999-recommendations Beatrix 2000
Section view of the 15B27 winze
Any deviations from the ventilation layouts should be
discussed with and approved by the mine s appointed
ventilation officials Their task should also include
Plan of the 16A27 Stope
monitoring of the progress and standard of work
One of the most disturbing aspects uncovered during
this investigation was a long standing and pervasive
lack of discipline.
Discipline and self-discipline must be such that an
effective safety culture is developed throughout the
organization.
This event resulted in the death of 7 mine workers
Beatrix 2000-Conclusions Beatrix 2000-Conclusions
The explosion was due to the ignition of
The hazards relating to: a)persons working
flammable gas.
without FGMI s b)accumulation of water and
The accumulation of gas occurred when
its effect on airflow and the build up of
water in a water trap prevented the flow of
flammable gas c)use of compressed air
ventilating air from diluting emissions of
equipment and the risk of static electricity,
flammable gas.
were not adequately recognised and dealt
The FGMI of the now-deceased miner was
with.
found after the accident to have been left at
Hazardous Locations were not demarcated
the bottom of the travelling way in fresh air at
a position of some 160m away.
Beatrix 2000-recommendations Beatrix 2000-Recommendations
Hazard identification. Geological anomalies
The employer to institute a system of
to be projected on both strike and dip to
monitoring flammable gas emissions by
warn development crews.
means of strategically placed detector heads.
Declaration of hazardous locations. The
The employer must ensure that every gang
HIRA process must be applied to all workings
has at least two FGMIs.
to determine the assessed flammable gas
Every working place is inspected by officers
risk of such workings.
of the Ventilation Department and by
A system must be installed to give ample
members of an in-house audit team as part of
warning to all persons who may be affected,
of any breakdown in the ventilating system. the employer s Risk Management System.
3
Beatrix 2001 Beatrix 2001-Conclusions
10mł/s to
10mł/s to
11mł /s to RAW System
11mł /s to RAW System
12mł /s to RAW System 1 and 2
12mł /s to RAW System 1 and 2
The apparent ignorance with regard to the
RAW System 1 1 and 2
RAW System 1 1 and 2
12mł /s to
12mł /s to
Gas Mixing Point
Gas Mixing Point
RAW System 2
RAW System 2
potential hazard led to a plug of flammable
gas being introduced into the G Drive where
D
D
A
A
16
16
48 10 3 37
48 10 3 37
B 21
B 21
non-explosion protected electrical equipment
C
C
48
48
E
E
Tendency
Tendency
10
10 was installed and used.
10
10 A spark was created presumably when the
4
4
electricians attended to the electrical
8
8
switchgear, which resulted in an explosion.
VENTILATION ARRANGEMENTS
VENTILATION ARRANGEMENTS
ON 16 LEVEL, BEATRIX MINE
ON 16 LEVEL, BEATRIX MINE
All figures shown represent mł/s of air
All figures shown represent mł/s of air
This accident resulted in the death of thirteen mine workers
Beatrix 2001-Recommendations
Evaluate all fans installed in parallel and
Beatrix 2001-Recommendations
ensure that they are equipped with non-
An assessment must be made of all
return flaps.
underground workings to establish all
All electrically-driven underground fans must
flammable gas sources, the emission rate and
be evaluated to ensure that they will not
the concentrations
restart automatically after a power
Install effective ventilation controls to ensure
interruption or failure.
that no accumulations of flammable gas occur
All electrical equipment and switchgear must
and prevent the contamination of other
be properly labelled to establish exactly from
workings.
where such equipment is fed and controlled.
Only explosion-protected equipment must be
Ventilation layouts must be designed to fail to
used in declared hazardous locations.
safety
Beatrix 2001-Recommendations Brief Analysis of Accidents
 There are three main reasons leading to
flammable gas accidents: changes to
Mine management must address
ventilation, not testing for gas, and
shortcomings in the systems of supervision,
contraband including tampering with
control and co-ordination in order to ensure
caplamps to make ignitors. The ventilation
that health and safety concerns are
conditions are not necessarily non-standard
integrated into daily activities.
or poor ventilation, but are also cases where,
for example, the ventilation had recently been
All recommendations made after the previous
changed, or a fan had not been operating.
flammable gas explosion (15 May 2000) must
This has allowed a build up of gas, which is
be adhered to
then moved by the ventilation being restored.
 Gap 504
4
16G23ST
/
16G23ST
/
1 G2
HXC
1 G2
HXC
6
1ST
/
6
1ST
/
HXC
HXC
1 XC
H
1 XC
H
6
/ ST
6
/ ST
1 G2
THXC
1 G2
THXC
1 G2
THXC
1 G2
THXC
1 G2
THXC
1 G2
THXC
6
9N
/
6
9N
/
6
7N
/
6
7N
/
6
5N
/
6
5N
/
Brief Analysis of Accidents Relevant outcomes of GAP 504
10mł/s to
10mł/s to
11mł/s to RAW System
11mł/s to RAW System Gas concentration variation in 16GW Drive as a function of time and airflow The figure below shows the number of gas reports to the DME
12mł/s to
12mł/s to
RAW System 1 and 2
RAW System 1 and 2
RAW System 1 1 and 2
RAW System 1 1 and 2
25,0 45,0
12mł/s to
12mł/s to over the ten year period, compared with the numbers of injuries
Gas Mixing Point
Gas Mixing Point
RAW System 2
RAW System 2 40,0
20,0
35,0
and fatalities. Short term declines in flammable gas reporting
30,0
D
D 15,0
A
A 25,0
have twice preceded increased fatalities and injuries due to
16
16
48 10 3 37 21
48 10 3 37 21 20,0
B
B
C
C 10,0
15,0
accidents  (Reporting will continue into SAMRASS @ DME)
48
48
E
E 10,0
5,0
Tendency
Tendency
10
10 R e p o r t e d i n c i d e n t s , f a t a l i t i e s a n d i n j u r ie s .
5,0
F l a m m a b l e g a s 1 9 8 4 - 1 9 9 7
0,0 0,0
3 5 0 0 . 0 3 5
R e p o r t R a t e
10
10
Time [Minutes]
In j u r y R a t e
3 0 0 0 . 0 3
48 mł/s 22mł/s 17,5mł/s Fl. Gas [17,5] Fl. Gas [22] Fl Gas [48]
4
4 F a ta l it y R a t e
2 5 0 0 . 0 2 5
8
8
Once the plug has been
Once the plug has been
2 0 0 0 . 0 2
dislodged it remains as a
dislodged it remains as a 1 5 0 0 . 0 1 5
VENTILATION ARRANGEMENTS
VENTILATION ARRANGEMENTS
ON 16 LEVEL, BEATRIX MINE
ON 16 LEVEL, BEATRIX MINE
1 0 0 0 . 0 1
All figures shown represent mł/s of air
All figures shown represent mł/s of air
plug and does not easily
plug and does not easily
5 0 0 . 0 0 5
disperse.
disperse.
0 0
1 9 8 4 1 9 8 5 1 9 8 6 1 9 8 7 1 9 8 8 1 9 8 9 1 9 9 0 1 9 9 1 1 9 9 2 1 9 9 3 1 9 9 4 1 9 9 5 1 9 9 6 1 9 9 7
Y e a r
Guideline on Explosion Prevention-
Relevant outcomes of GAP 504 Mines other than Coal
Regi CH4 CH4 C H C2 H C H C3H C4 H C H H2 H2 He N2 LEL UEL
2 3 4
Objective:
on aver aver aver aver aver aver aver aver
6 6 8 8 10 10
age age aver aver aver aver aver aver age age age age age age
(rang (rang age age age age age (rang (rang (rang (rang (rang (rang
age
e) e) (rang (rang (rang (rang (rang (rang e) e) e) e) e) e) To assist the employer
e) e) e) e) e)
% % e) % % % % com
Air- Com % % % % % % Air- Com Air- Air- com busti
of every mine other
free busti Air- Com Air- Com Air- Com free busti free free busti bles
bles free busti free busti free busti bles bles in air
than coal to compile a
bles bles bles in air
COP which, if properly
Wits 47 65 4,5 5 1 1,5 0 0 22 31 25 1 4,5 22
compiled and
(15- (18- (0 -9) (0-9) (0 -2) (1-5) (0- (0 - (0- (0 - (0 - (0-8) (4 -5) (15-
70) 100) 0,1) 0,1) 60) 80) 60) 40)
implemented, will
FS 88 100 0,1 0,2 0 0 0 0 0 0 2 13 5 15
considerably reduce the
risk of an ignition of
(84- (100) (0 - (0- (0) (0) (0) (0) (0) (0) (0 -5) (9- (5) (15)
95) 0,6) 0,8) 20)
flammable gas.
Bv 57 99 1 2 0,1 0,2 0 0 0 0 1 45 5 15
(24- (96- (0,6- (1-3) (0 - (0- (0) (0) (0) (0) (0 -3) (37- (4,9- (14,9
64) 100) 2) 0,5) 0,5) 73) 5) -15)
Summary of gas analysis from the various mining regions
Classification of Hazardous
Locations Criteria for Hazardous Locations
FIRES AND EXPLOSIONS - REGULATIONS
A hazardous location is any area where,
Report to Employer
under normal operating conditions, there is a
continuous presence of flammable gas
5.1(1) The employer must ensure that a competent person
concentration equal to or greater than 0.5%
reports to the employer at appropriate intervals determined in
in the general body of the air.
accordance with the mine s health risk assessment:
(a) The effectiveness of precautionary measures taken to  General body of the air is any point in the
prevent or suppress explosions of coal dust or flammable gas;
environment more than 500 mm from a
and
known flammable gas source.
(b) The adequacy of measures in place to prevent, detect and
- there are also specific areas of coal mines that need to be
combat the start and spread of mine fires.
declared as hazardous locations
5
1 6 G 23 S T H X/
1 6 G 23 S T H XC
1 6 G 21 S T H X/
1 6 G 21 S T H XC
16 X/ C ST H
16 X/ C ST H
/
C
/
C
16 G 29 N TH X/ C
16 G 29 N TH X/ C
16 G 27 N TH X/ C
16 G 27 N TH X/ C
16 G 25 N TH X/ C
16 G 25 N TH X/ C
i
[
[ % ]
O xygen C on cent r at o n % ]
l
i
F a m m abl e Gas C on cent r at o n
0
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
4 5
5 0
5 5
6 0
i
re p orte d
l
u
t
N m be r of inc ide n s
to fa mm ab le g as ,
p er 1 00 0 e mp loy ee s
F a tality an d n jury rate du e
Flammable Gas Fatalities and Injuries
1988 to 2001 In Conclusion & .
After carefully studying the conclusions and
40
recommendations from the three investigation
35
30 reports, the congruence in the findings of
25 GAP 504 can be clearly seen i.e. the three
Injuries
20
primary causes of flammable gas explosions
Fatals
15
are the changes to the ventilation system
10
(changes without the consent of the
5
ventilation officer, blockages etc), the poor
0
detection of the presence of flammable gas
and the use of contraband.
In Conclusion & . References/Acknowledgments
Statistics on Mine Accidents (Methane) 01/01/1998 to
It is hoped that the experience and
31/08/2001  SAMRASS database, Department of Minerals and
Energy (DME)
knowledge gained through this case
Investigation Reports (Motaung, Dow and Kritzinger)  DME
study and projects like GAP 504 would
(Mine Health and Safety Inspectorate) and Chamber of Mines
Information website (COMINFO)
equip all of us to ensure that there
(http://196.26.82.197/ohs/ohs.htm)
Safety in Mines Research Advisory Committee (SIMRAC)
would not be another flammable gas
research reports GAP 504, Cook et al.
explosion
Guidelines for a Mandatory C.O.P  approved on 12/10/2001 by
the MHSC
Mr. Marco Biffi  CSIR (Miningtek )
Mr. Doug Rowe  Department of Minerals and Energy
6
1988
1990
1992
1994
1996
1998
2000