It appears to me that the investigation into the Burns Lake mill explosion has been fruitless due to the lengthy amount of time for a report. If the cause of this explosion was determined earlier, the Lakeland Mills explosion would not have occurred.
The Lakeland Mills explosion glaringly points to sawdust as the culprit. One just has to investigate videos on YouTube to realize this. If there is doubt as to the seriousness and danger of dust in mills, then bring in the knowledgeable experts from the United States.
I have worked in the planer mill next door to Lakeland Mills for many years. Machinery operators in the mill regularly used air hoses at high pressure to clean their work area, creating such a huge mass of fine particles throughout the mill that I could not breath without a face mask. I never used an air hose to clean and urged people to use a broom and dust pan instead, or a vacuum cleaner. It is no use to measure the dust in the mill during normal operation when nobody is using an air hose to blow dust around.
The dust that was blown around settled inches deep on the wide electrical conduits, clogged the exhaust fans and clogged the radiators of the heating fans to such an extent than we did not want to turn them on. The dust also settled on all overhead surfaces in the mill and stuck to walls and ceilings and electrical equipment. The dust would get into electrical switching equipment, inside electric motors and stick to surfaces due to the static electricity in the dust. It is my opinion that anything that moves creates static electricity and this allows it to adhere to all non-moving surfaces.
Imagine this scenario: It is lunchtime. The mill is idle. This is the time maintenance people are working. Someone is using an air hose to clean their area. They are blowing off electrical equipment that is shut down in order to repair it, or they are blowing down a piece of machinery that is seized and that seizure is caused by a red hot shaft bearing. Electrical switches make a spark when activated and red hot bearings can ignite dust. The small area of dust ignites and a small explosion occurs. That small explosion shakes more dust loose.
That in turn causes a substantial explosion. The whole mill shakes, loosening all the dust in the mill. Then there is a gigantic explosion that consumes all the loose dust in the mill. The rest is consumed in the resulting fire.
This is my opinion as to what has occurred. Dry logs are definitely a factor as is the type of wood. But all sawdust can become dry and explosive over years collecting in a mill that has a roof overhead and walls with no opening windows. Opening windows are too expensive to install in the new mills that are giant contained boxes. Older mills had just a roof overhead and no walls. A gusty day could remove all the loose dust.
I am sure there have been a lot of studies in the United States on dust explosions and information on how to prevent them. If something is not done quickly and soon, there may be another mill in Canada with the same old scenario, ready to explode.
