The lower the temperature that the char is produced at the more hydrocarbon residue that can stay. Biochemical decomposition such as in a compost pile can cause heat build up until probably the hydrocarbons ignite first, most likely in gas form then igniting the charcoal. There may be some sort of ignition taking place from chemical reactions such as the way linseed oil ignites in oily rags. I can’t help but suspect that nitrogen is involved in there somewhere, know of no evidence to prove this. If anybody can find the exact breakdown sequence of linseed oil this would provide a valuable insight.
Lastly, solar ignition from solar heat buildup in a small hole could possibly reach ignition points. Let me shed some light on another viewpoint. I have done extensive experiments with ignition of genuine black powder. With every case I looked at it was always the sulfur that gasified and then ignited first, before the charcoal. This leads me to believe it is hydrocarbon impurities in the char lowering the ignition point dangerously. The higher temp retort char I have done ignition tests on seems to have a high ignition point. The highest sustained temp during the charring that the whole charge was exposed to, would determine the volatility point of any hydrocarbon present. In other wards say you have part of the charge you are working with only reach F 300. When the char achieves that temp again it will again start to release the hydrocarbon not yet released. The gas being released is the culprit. Pure carbon has a very high ignition temp.
Now a static spark which can be very high temp, can ignite fine charcoal dust. For this reason a bit of moisture is recommended to keep the static charges down. In dry climates this can be the biggest hazard. When I first learned the art of crushing black powder cakes which is the most dangerous part, I would breath on the powder to moisten the air in the mortar and pestle. Then I would not use any procedure producing hot friction points. Fireworks factories use grounded touch pads to dissipate static electricity. They also commonly use controlled humidity to dissipate the same thing.
If one mixes potassium chlorate with sulfur, a scrape in the mortar by the pestle can easily detonate the charge with frightening consequences. A charge the size of your fingernail clipping can be louder than a firecracker. (This is the bang in firecrackers today anyhow. The aluminum powder provides the flash) If you use just charcoal alone with the potassium chlorate, that reaction will not happen. The chlorate is releasing it’s oxygen from the heat of friction, but the ignition temp of the char is too high, even in the presents of pure oxygen.
This again demonstrates how the lack of research into alternative fuels can be a dangerous situation. The info gathered by positively identifying the parameters of the reactions I just discussed would go a long way toward fire safety in general. Why does it take a fatal explosion at a fireworks factory to give the incentive to provide research data? Charcoal is the oldest refined fuel, and yet has some of the most primitive research data surrounding it. It was created first by forest fires. Just use common sense, knowledge of the reactions, and store your char outside, away from anything you wouldn’t store a pile of coal next to, like a chimney.
I have never heard of a truly wet pile of charcoal or coal igniting by accident. In the State of Ohio, USA, both are stored outside, without covers that could trap escaping gas. We handle a large percentage of the nations coal supply. Producing, shipping, coking, and burning all included. Most of the silos I see, are iron or brick and have drying/ventilation systems. Careful and common sense, better than natural gas hu?
One comment. In about 1910 there was a huge mine disaster out east somewhere. Hundreds of coal miners were killed. It was shortly after that that the U.S. Bureau of Mines was formed to look into mine explosions and safety in all the mines overall in the country. Many have said that the BOM stands for Blood of Miners. People had to die by the hundreds before any government body would do anything about it. Then in 1996, Newt Gingrich succeeded in eliminating the U.S. Bureau of Mines completely. It was the only U.S. agency he was able to eliminate in his Republican Revolution. Remember that crap? He was going to shrink the federal government. Total Bureau of Mines budget was only about 150 million bucks at the time…a drop in the federal bucket / trough. Well, I lost my job due to that ignorant bastard. The science was pretty much dead at the Bureau by then, but it did do some useful things. I had hope, but there were too many dolts in charge of the place by the time I got there. Managing the science was more important than the science itself. It was sad but very true.
I’m so sorry to here that. All of that. Several of my Great Grandfathers started out mining coal before pouring iron and working steel. It was considered a step up to move to the mill. That is unless you worked in the coke ovens. That was worse than mining coal. One of them(or maybe it was a cousin) I believe died of black lung. Working on a Blastfurnace tapping crew was more dangerous, but celebrated as skilled, and that was what the Slovaks(like my kin) excelled at. I remember my Grandmas Neighbor telling me about the days when blastfurnaces were run by steam. He repaired blowers and did other routine blacksmith type maintenance. Over the years, he ran Em all. In more recent memory, my late Uncle Bill worked at a company called something like Mine Safety Equipment Co. He used to study new plastics for hardhats and other worker protection. They worked hand in hand with the bureau of mine safety.
As a child I remember seeing funny shaped pieces of plastic scrap from injection molding machines. Uncle Bill used them as landscape sculptures. I believe that the accident was in West Virginia, and there was a gas explosion in a mine. Then a separate indecent where a tailings dam broke, killing many residents of the local town in a flash flood. The news media penetration into the hills also had a lot to do with breaking news coverage of what was going on all along on a smaller scale. We cannot talk mining without discussing union activity. The most catastrophic union strike happened in south central Colorado. The miners left the company town to set up a strike camp out on the plains. The company called in the militia and they slaughtered the whole camp while sleeping in their tents. The death toll was in the hundreds. Women, infants, and children, all included with those miners. All those who labor in unions today, have those earlier pioneers to thank for their good jobs. Miners are like farmers who work harder and often have less to show for their efforts. Where would the world be with out them?
Unions as we know them are outdated in some areas. Some areas of work would probably be in trouble without them. Where the corruption in the Union outweighs the corruption in the company, I’m for trashing them. The only time the common uneducated laborer ever made forward strides in compensation, the Unions were to thank. The supply of unskilled workers is so large that market forces do not do the job. Where skilled workers are concerned the Unions play a helpful role at recognizing safety concerns. These might be over looked in the drive for profit. Non Union jobs pay higher, because of the parallel Union pay scales. In this country, where we can sue over anything, the lawyers and insurance companies over play that safety concern role. This is what happens when the profit motive (for the lawyers) overvalues reasonable safety standards, at the expense of company profit and survival. Even the most die hard Union man, will admit that he wishes the companies would just have done their job, of taking care of their workers in the first place. I believe that the modern role for Unions should be to act as safety and compensation consultants. There is no need for every worker to be in the Union if the company is in partnership with the Union. The industries that escaped Unionism usually didn’t abuse their workers in the first place. Remember that Henry Ford started out non Union but the wages he paid were higher than most competitive jobs offered. Competition from other car companies slowly eroded that advantage. If he had continued to lead pay scales, the Unions would have organized his competition first and held back as long as his wages were competitive. The hidden benefit is getting and retaining better workers.
As they say, you get what you pay for. If you pay comparatively low wages, you get a Union. I think the Electrical workers and firemen’s Unions, do a good job overall, of making dangerous jobs as safe as they can be. Retail workers Unions have no clout because they have little to offer other than slightly higher wages to offset dues. Their is much to be argued on both sides, so the situation must be taken case by case. I have been self employed since I graduated from high school, so I understand fighting for your own agreement. Their are days that I wish the landscape industry could Unionize due to the lack of support for payscales. I’m not sure it would help anything though, so I look for supplemental income outside the low paying industry. People pay for part time landscapers, so that is exactly what they get. If the quality of work was recognized, I’d make double what I do. Instead low bid rules. Everybody thinks this is easy money, till they loose money for a couple of years and break their back, dragging bid prices down as well. They quit after making sub minimum wage and loosing their initial investment. You really have to love this line of work to do it for years. Union or no. Farming is about the same.