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Anthracite is the most metamorphosed type of coal, but still represents low-grade metamorphism, [a] in which the carbon content is between 86% and 97%. [1] [5] [6] The term is applied to those varieties of coal which do not give off tarry or other hydrocarbon vapours when heated below their point of ignition. [7]
Smokeless fuels generally have a high calorific value, with that of anthracite being greater than dry wood for example, and many smokeless briquettes are made from this type of coal. Thus anthracite has a calorific value of 32.5 MJ/kg compared with that of dry wood of about 21 MJ/kg.
Lignite (derived from Latin lignum meaning 'wood'), often referred to as brown coal, [1] is a soft, brown, combustible sedimentary rock formed from naturally compressed peat.It has a carbon content around 25–35% [1] [2] and is considered the lowest rank of coal due to its relatively low heat content.
The 300-foot-wide, 75-foot-long (91 m × 23 m) pit was made up of a 50-foot-deep (15 m) strip mine that had been cleared by Edward Whitney [clarification needed] in 1935, and came very close to the northeast corner of Odd Fellows Cemetery. There were eight illegal dumps spread about Centralia, and the council's intention in creating the ...
Subsidence can occur above tunnels, causing damage to infrastructure or cropland. Coal mining can also cause long lasting fires, and it has been estimated that thousands of coal seam fires are burning at any given time. [150] For example, Brennender Berg has been burning since 1668, and is still burning in the 21st century. [151]
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[5] [11] Ultimately, exposure of arsenic over a long period of time can cause mortality. [5] Furthermore, low levels of arsenic exposure can cause irregular heartbeats, nausea, diarrhea, vomiting, peripheral neuropathy and vision impairment. [9] [5] Mercury: Chronic exposure of mercury from coal ash can cause harm to the nervous system. [5]
The FDA has a guide for how long you can safely store food in the freezer, and it’s not as long as you’d think. Most raw and cooked ingredients only stay good for a few months at most.