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May 17th, 2006 was a sad day in
Kimberly, British Columbia. Four bodies were recovered from a
water sampling shed, which included an employee, a consultant
contracted by the mine owner, Teck Cominco, and two first
responders. What happened to cause this tragedy and what can
we learn to prevent future deaths?
Confined Space was a Water Sampling Sump
The confined space involved was a water sampling sump, 1.5
meters deep with a small shed over it. Water from a waste rock
dump was channeled through a pipe and could be accessed
through the shed to test for chemicals leaching from the rock
tailings. The chemical reaction between the sulphide bearing
rocks, water and oxygen consumes oxygen and produces carbon
dioxide and sulphuric acid. This had caused no previous
problems but, in 2005, the waste rock dump had been covered
with a layer of soil in order to slow the oxidation process.
This channeled more of the carbon dioxide through the pipe and
into the sampling sump.
Oxygen Poor Atmosphere Determined as Cause of Death
The direct cause of the deaths was an oxygen poor atmosphere.
Testing after the fact revealed oxygen levels as low as 2% in
the sump. Anyone in that atmosphere likely became disoriented
within a few breaths, lost consciousness within a minute and
died of asphyxiation in just a few minutes more. The
investigation that followed had a surprising finding. No
atmospheric testing had ever been performed despite the
fact that the sump qualified as a confined space. Testing,
especially in the beginning of the sampling program, would
have revealed low oxygen levels and prompted some simple
precautions before the O2 levels became dangerously low.
Actions of Rescuers also
Contributed to Deaths
A contributing cause of these fatalities was the actions of
the rescuers themselves. After finding the first victim at the
bottom of the sump, the Teck Cominco employee immediately
called emergency services and climbed down into the sump
without any protection. The ambulance crew that responded to
the emergency compounded the tragedy and both descended into
the sump, one after the other, to recover the previous victim.
To enter a confined space, especially one which has been
proven to be hazardous because of the presence of a casualty,
without testing the atmosphere and either ventilating the
space or wearing breathing apparatus is a recipe for disaster!
Unfortunately, the incident at the Sullivan Mine is a classic
example of a confined space incident where a possible hazard
is overlooked because no testing is done. Additionally,
rescuers enter the space without testing and taking
precautions. Let this be a lesson learned to all of us so
these types of incidents never happen again.
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