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16

The most important source of natural gas is natural gas. This is why it is called natural. It is not "made" from oil or coal. Natural gas forms by decomposition of organic material. Whether the organic material decomposes to coal, oil, or gas depends on the composition of the original material, time, pressure, and temperature. In theory, oil (=long chains ...


12

The efficiency of coal as a source of electricity is very low: typically of the order of 30%. So losses are of the order of 70%. But losses due to energy expended in the extraction of the coal itself only form a very small proportion of this. Estimates for extractive losses tend to be of the order of 0.5-5%. That's a huge relative range, because the energy ...


8

Craters actually can be identified by formation of high-pressure materials such as diamonds or stishovites and coesites (varieties of shocked quartz). A good example of this is the Popigai crater in Russia. Pressures and temperatures at subduction zones are usually too low to form big diamonds but microdiamonds (10-80 microns) were discovered within ...


8

Coal, oil and gas can be found anywhere on Earth: on land and on sea. The Japanese once mined coal from beneath the sea floor, using Hashima Island as the base of operations. The island is only 6.3 ha in size. The British also mined coal from under the sea, in the north east of England. As for oil, the following picture from USGS shows the current oil-...


7

There isn't a risk to putting it out other than the attempt failing, it is just impractical to do so once a large coal vein catches fire. You can read more about the Centralia, PA coal fire on wikipedia which sits on top of anthracite coal veins that have been burning for a little over 50 years and are likely to continue to do so for a few hundred years. ...


6

I'm not sure why you are including shale in your question, unless you are referring to carbonaceous shale, which in not coal, but shale with carbon throughout the matrix of the shale. Shale is an argillaceous rock, and argillaceous rocks are "detrital sedimentary rocks" [1]. They are composed of clays and the bedding plane within the shales is "due to the ...


5

A significant part of the natural gas used around the world today comes from oil fields. On top of the oil is a layer of natural gas, and in the crude oil is dissolved natural gas. This will be released when the pressure drops during the extraction of the crude oil so the natural gas will be separated from the oil during the extraction process. Earlier ...


4

Reference [6] under that Wikipedia article on spontaneous combustion gives you some answers: "The Fire Below: Spontaneous Combustion In Coal". DOE/EH-0320, Issue No. 93-4. US Department of Energy. May 1993 How Coal Self-Ignites The coal's temperature begins to climb above ambient. At about 150-300 degrees F, it begins to give off minute, but ...


4

Sulphur/sulphides in coal may be one of the causes of self combustion. A slight diversion - in some metal sulphide mines, such as copper, at high level of sulphides in the ore, the sulphides can oxidize thus creating sulphide fires. If a lot of dry dust is produced during stope blasts, during the mining process, sometimes the sulphide dust can cause a ...


4

I'm assuming you mean underground fires within coal seams whether they are caused naturally or through human neglect or error. Regarding the possibility of them "triggering volcanic eruptions by affecting the flow of magma or by some other means", the answer is no. Underground coal seam fires are mostly smoldering type fires rather than raging fires, due ...


4

For the US, there are several sources: Mineral Resources Data System (MRDS) MRDS is a collection of reports describing metallic and nonmetallic mineral resources throughout the world. Included are deposit name, location, commodity, deposit description, geologic characteristics, production, reserves, resources, and references. It subsumes the original MRDS ...


3

Coal and other organics like wood and straw decompose when exposed to oxygen, that decomposition is an exothermic oxidation reaction so it heats the material around it which accelerates the decomposition. This can be reasonably harmless if there's enough airflow to cool the pile and carry away the small volumes of flammable volatile gases formed by what is ...


3

Nice idea but the practicalities are impossible. There are parts of Indonesia which have out-of-control peat and coal fires which have been raging for years, and even decades, despite those areas receiving well in excess of two metres of rain a year. See for example: Whitehouse AE and Mulyana AAS, (2004) Coal Fires in Indonesia. International Journal of ...


2

Rocks are not necessarily made out of minerals. Yes, most of them are but it's not a requirement. Also, not every collection of minerals is a rock. For instance, sand is not a rock. This is not limited to rocks of biogenic origin. Take for example obsidian, or volcanic glass. In some cases there is not a single mineral in the rock, yet it is a rock. My own ...


2

The most important factor for petroleum becoming gas isn't a substance, it's temperature and pressure. Most reservoirs have varying degrees of both; the T&P dictates how much of each will form. Knowing the type of field tells you what you should expect, be it a natural reservoir (black gold), or peat bogs (oil sands). Geologists often refer to the ...


2

Coal, which is essentially pure carbon, slowly oxidizes, it is the same reaction as it burning just much slower. This is the major source of heat for self-heating of coal. Many things that will burn will also slowly oxidize under normal temperatures, it is just not a sustained chain reaction that a fire is. Since this is weak slow process there is a large ...


2

Prior to the carboniferous period, and until the human industrial era, the majority of carbon dioxide in the atmosphere was due to volcanoes. For billions of years, geological processes like volcanic eruptions controlled the carbon concentration in the atmosphere, as volcanism is the major way that carbon rises from the mantle into the atmosphere. Most ...


1

Short answer, its not well studied. It is most likely a diagenic process just because that is the source of most fractures in rock. https://www.sciencedirect.com/science/article/abs/pii/S0166516297000128 https://www.sciencedirect.com/science/article/pii/S1674775514000341


1

About 900 grammes of CO2 for each 1kWh of electricity. There is some variation: very modern super-critical coal plants can be lower. But 900g is a reasonable central estimate. Note that that's just CO2 from combustion. It can be higher, when we include CO2 and CH4 emissions from the rest of the coal supply chain too.


1

There's no significant difference in distribution beneath land and sea. Recovery is all about accessibility. There's plenty of coal under the sea, but we just can't get at it - fortunately! To avoid carbon-driven disaster we have to leave most of the coal and oil where it is, under land or sea.


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