Por Redaccion 
José Antonio Sáenz de Santamaría believes that the investigation, which may take many months or years, will determine whether it was preventable or not
«What happened at the Cerredo mine is a very rare event, Grisú explosions are something that happens very few times.» These are the words of geologist José Antonio Sáenz de Santamaría and Benedet, a retired professor from the University of Oviedo and an expert in mining who participated in the investigation of the last Grisú explosion in a mine in the Principality, the Nicolasa shaft in August 1995 with the result of 14 miners deceased.
In statements to Europa Press, Sáenz de Santamaría, who has been the head of geology at Hunosa for more than 20 years, has analyzed what could have happened this Monday at the Cerredo mining operation in Degaña, where five men lost their lives and four others were injured.
He explained that Grisú is undoubtedly the «biggest problem in coal mines» and while it is true that explosions like the one that occurred this Monday were more common in the early 20th century when there was a «very primitive» mining, they are very rare «today with an absolutely modern mining including this Cerredo installation.»
And this geologist wants to make it clear that the mine in Degaña where the tragedy occurred is a modern facility with «a three-kilometer inclined plane where trucks go all the way down.»
Today, what the current owning company was aiming for was to explore the possibility of extracting graphite which, due to the geological circumstances of the Degaña and Cangas de Narcea areas, it is possible that it had formed in the coal layers.» According to this expert, the investigation may reveal whether the deceased and injured workers were in that area of the mine.
Regarding what could have caused the explosion, we will have to wait for the investigation, but the geologist assures that for it to occur, three factors had to come together: first, «for some unknown reason, either because a ventilation was stopped, or even though there was ventilation, there was a bell there and it filled with Grisú, which is 98% methane, for some reason there was a Grisú pocket, meaning an accumulation of Grisú.»
Secondly, that the concentration of Grisú in the air was between 4 and 14%, because as Sáenz de Santamaría explains, if Grisú in the air is less than 4% or more than 14%, it does not explode.
Thirdly, the reaction does not occur if there is no activation energy, and in the case of the mine, this must be a spark «caused by a machine or any other factor like if an iron falls and hits another, and a spark jumps, or a part of a turbine breaks, flies off, hits a panel, and a spark jumps, that is what will be investigated.»
«What is clear is that if these three conditions are not met, first, the gas pocket falls, second, the gas concentration in that location is between 4 and 14, and third, there is a spark, the explosion does not occur. Therefore, if these three conditions must be met, the event is very rare,» explains José Antonio Sáenz de Santamaria.
«COULD IT HAVE BEEN AVOIDED?»
Once the explosion has been explained and in response to the question of whether it could have been avoided, the expert geologist says that this is something that cannot be confirmed or denied and makes a comparison with airplanes that fall due to one circumstance or another.
«Let’s see, it’s like if you ask me if an airplane falling could be avoided. There are 100,000 flights every day, and every now and then one falls, could it have been avoided? I believe that aviation is the safest method of flying. Could this accident have been avoided? It must be said that if a machine or part of the installation caused a spark, that is also very rare because the machinery inside is special. Could it have been avoided? Well, I don’t know, that depends on the investigation,» he added.
In this sense, this geologist, who has over 40 years of experience in oil exploration, coal mining, mentions that today there are Grisú, carbon monoxide, and oxygen sensors, there are «a lot of sensors in the mine,» and for many years, the sensor data has been sent outside.
He also points out that mining activity is the most regulated industrial activity in the country «with five bodies of difference from the next one.» «No industry has such extensive, well-worked, and controlled regulations like mining activity, both by companies and by the government.»
VERY COMPLEX INVESTIGATION
Therefore, we will have to wait for the investigation to determine what really happened. This expert recalls that the investigation of the Nicolasa shaft accident, in which he participated, lasted 18 months, and he speculates that in this case, it will also take «many months or years» to understand what happened, but he is also certain that «it will be known» because there are responsibilities to be addressed.