A major incident at Mir,
Alrosa’s longest-operated mine, saw 151 miners trapped on August 4 when about
300,000 cubic meters of water flooded into the underground mine shaft from the
open-pit mine above it. While 143 miners were brought to safety within the
first two days of the incident, eight were declared dead after three weeks of
being trapped 210 to 310 meters below the surface.
In those first weeks, a
320-person rescue operation continued around the clock in an effort to clear
the eastern Siberian mine of the underground water. The operation included
staff from the Emergency Ministry’s mine rescue and mine diver teams, and 19
units of equipment, with three emergency pumps working at a rate of 3,750 cubic
meters per hour.
Nonetheless, on August 15, the
level of flooding rendered rescue efforts at 310 meters below the surface
unsafe. Deputy Prime Minister Yuri Trutnev, who is also the presidential envoy
to the Russian Far East, had flown to the site the day before, and said the
rescue mission would remain a number-one priority as long as it was technically
possible.
What could have been done
differently?
“There are two questions we
must find an answer to,” Trutnev said. “Could this incident have been avoided,
and could it have been predicted in time to halt the works and move all the
staff to safety?”
In an exclusive interview with
Rapaport Magazine, Nikolay Pokhilenko — head of the Institute of Geology and
Mineralogy at the Russian Academy of Sciences, and an expert with over 35 years
of diamond-exploration experience in Russia and other countries — answered
these questions.
“The subsoil conditions around
the Mir mine are unique in that they contain abundant aggressive mineralized
underground waters capable of melting permafrost ice at subzero temperatures,”
said Pokhilenko. “One possibility here is that the rock separating the mine’s
crater from the underground operation could have contained a body of ice, which
normally makes the rock even stronger, yet it could have been eroded by these
aggressive waters, creating a weak spot that allowed the breakthrough.”
This is the only place in the
world where diamonds are mined in such extreme conditions, he explained. “There
is no known methodology that could have allowed [experts] to diagnose and
predict a situation like this,” he continued, adding that the Mir mine accident
called for thorough research and development of such methodology.
As of press time, Alrosa said
it was planning to bring in an auditor with experience in underground
diamond-mining facilities that had similar hydrogeological conditions.
Despite the flood, Alrosa
expects to reach its production goal of 39.2 million carats for 2017. The
company plans to increase production at its other mines, especially the Jubilee
pipe, to compensate for the decline in output from Mir, which yielded around 2
million carats in the first half of the year — 11% of Alrosa’s total output.
The Mir mine is one of the
richest diamond deposits on Alrosa’s roster, producing an average of 3.7 carats
per tonne
In 2016, the Mir
underground mine produced a total of3.19 million carats
The Mir mine has 74.5
million carats of measured reserves according to the JORC Code assessment of
July 1, 2016, which is enough to keep production active until 2052
In the first six months of
2017, Alrosa’s total production went up 14% year on year to 19.3 million carats
Article from the Rapaport Magazine - September 2017. To subscribe click here.