SME incident in Singareni on 2nd June 2020
SME
incident in Singareni on 2nd June 2020
: Dr. Manoj Kumar Patel :
It
is often believed by manufacturers and users that SME (Site Mixed Emulsion) can remotely go wrong.
But one has to always keep it in mind that SME, SMS, ANFO, and HANFO are bulk in nature. So when something goes
wrong the consequences are disastrous.
Explosions
in SME in the July, 2009 in Singrauli, Madhya Pradesh is painfully remembered
as a black day in the history of SME manufacturing and use.
In
the parlance of explosives manufacturing we tell that the explosive demands
utmost humility and respect during interactions with it during manufacture,
storage, transport and use. A small slip her and a small inattention there
spell disaster.
“In a gruesome incident, as many as four Singareni Collieries Company Limited
(SCCL) workers were killed and two coal workers were injured on Tuesday, while
undertaking blasting operations at the SCCL open cast mine in Godavarikhani,
under Ramagundam region -3 area of OCP-1. This is one of the biggest accidents
in an open cast mine, as usually such major accidents occurred in underground
mines” – reported The Indian Express dated 2nd June 2020 based
on the accident that took place in SCCL.
More information was found in another
source that has reported: the
mishap took place around 11 am today morning at the OpenCast-1 mine in
Ramagundem. The workers first placed non-electric detonators attached to
boosters and filled with slurry (SME) into 32 holes at a depth of about 4
meters. When 33rd hole was being filled, the slurry suddenly exploded killing
them. SCCL sources said that all the victims were hired by a private contractor
for the work and not SCCL employees. Before taking up mining, earth has
to be removed and when some boulders are found, they are drilled and filled
with explosives and blasted from a distance. Unfortunately, it blasted much
before expected though usually everyone is asked to vacate the area. The
explosion happened even as the explosives were being filled in rocks today”.
What could have gone
wrong? Is the accident an outcome of reason or combination of reasons related to:
Charging practices in the Mines.
Quality Parameters and Sensitivity of
SME.
Static charges in the Shock tube.
Static charges in the Cast Booster
Cell.
Temperature in the blast hole.
Chemicals used in the nonel shock tube.
Whether the charging of SME was DTH
or poured from the top. The presence or absence of water in the blast holes
specially in the region of booster some time makes a difference on the spontaneous
initiations of the booster through nonel detonator.
SME
is assumed to be safe which in reality is not. It may be safer compared to
primary explosives but it is still hazardous. SME as the name suggests is a non
explosive material manufactured by mixing of two phases namely aqueous and oil.
SME is water-in-oil emulsion.
Matrix
density is usually in the range of 1.37 to 1.42 g/cc. Same matrix when brought
down to the density of “1.18 and less” becomes a booster sensitive explosive.
That means energy from the initiation of a detonator and booster can make SME
at density “1.18 and less” explode. Factors that may fasten the time of density
reduction are (a) high temperature of the SME, (b) use of higher percentages of
density reducing ingredients, (c) high temperature inside the blast holes, and (d)
top charging. The rate of gassing or “density fall test” is recommended to be
carried out before charging SME into blast holes.
Percentages
of inorganic nitrates, water, fuels and emulsifiers make a SME to change its
sensitivity towards detonator and booster. Inadequate percentages of nitrates
and water do change the sensitivity and strength of SME. It is a recommended
practice to check the SME for its chemical constituents like nitrates and water
contents before use in the field.
In India, compositions
of SME are approved by the PESO. The approval process emphasizes on
safety parameters that PESO follows in its Departmental Testing Section in
Gondkhairi. It is a good practice by the mines to ensure that SME manufactured,
purchased and used by them are in line with the PESO recommended formulations.
It
is often believed by manufacturers and users that SME can remotely go wrong.
But one has to always keep it in mind that SME, SMS, ANFO, and HANFO are bulk in nature. So when something goes
wrong the consequences are disastrous.
Explosions in SME in
the July, 2009 in Singrauli, Madhya Pradesh is painfully remembered as a black
day in the history of SME manufacturing and use.
SME
needs to be checked with respect to physico-chemical parameters like, density,
viscosity, rate of density drop, percentage of gassing agent, antistatic hose
pipes, antistatic material in boosters and shock tubes, temperature of blast
hole, presence of water inside the blast holes, sleeping period (time gap
between charging and blasting), flow smoothness, safety gadgets in the BMD
vehicles, etc.
Safety
characteristics and MSDS of the other accessories like (a) Booster and (b)
Nonel shock tubes must be understood. Users of these materials have to be under
the direct supervision of a competent person with respect to manufacturer, and user
mines. These cannot be left to casual labourers who maybe unaware of the
hazards arising from their inadvertent misuses.
Accidents
do not happen, they are caused.
==============================================
After read this article, came to know a lot of technical things about explosives, like The hidden hazards during manufacturing, transporting and handling and their prevention.
ReplyDeleteAll the points you wrote in this paper are true. From my point of view the main reasons of this accident are may be;
(1) Lack of supervision
(2) Untrained workmen and
(3) Overcofidence
Today in our Reliance Open Cast Mine, had been called a meeting and discussed about this accident. As we are from safety department, we had screened a report of this accident in front of all.
Nice to read your comments.
DeleteTry to implement SPOs in your place.
One more thing came in my mind that,
DeleteMay be there are drilling explosive charging work was going on simultaneously. Due to drilling heat was developed in the previous charged hole and the charged material also had self heat. Due to which the accident was happen.
This is what I am thinking only.
Your point is correct dear Ajit. But we need to have information about the specific activities taking place at the site during that fateful hour.
DeleteAfter reading you analysis i got clarity about the influence of handling, at application level over the explosive reaction.....
ReplyDelete1. While filling bore hole with slurry explosives after placing the booster along with nonel detonator ....it may generate static .
2. At user level
One has to check for density parameter...
Decrease in density .....increase chances for explosion even though operating at safe limits
3. Safety handling instructions for workers quick enough to understand and execute....
Should be Short and depth...