Hot answers tagged

31

Probably a bit over 4 km, in this South African mine: https://en.wikipedia.org/wiki/Mponeng_Gold_Mine But as the link mentions, the mine operators go to considerable lengths to reduce the mine temperature to endurable levels from the 66°C/151°F of the surrounding rock. Note: This answer is for the original question, where the OP asked for the deepest ...


26

Yep, mining can trigger earthquakes. According to a Scientific American article: We've been monitoring [The Geysers] since 1975. All the earthquakes we see there are [human] induced. When they move production into a new area, earthquakes start there, and when they stop production, the earthquakes stop. This is talking about geothermal power. They create ...


19

Since you termed it based on sea level, the gold mines in South Africa are not the deepest, they begin at an elevation of ~1500 m, meaning their 4 km depth is only 2.5 km below sea level. The Kidd mine in Canada is 2.9 km deep and is located at an elevation of only ~250 m above sea level making it's depth 2.65 km below sea level. https://en.wikipedia.org/...


19

Sound-like waves are routinely used to image the subsurface, but mostly well below the ultra-sound band. Several methods involve sound-like vibrations: Reflection seismic — the most important subsurface remote sensing tool we have Refraction seismic — important, but niche, and has a lot in common with reflection Acoustic logging — uses ultrasound, which ...


17

The Short Answer is Yes. The consensus is that humans can prematurely trigger earthquakes, and this paper in 1986's EPSL annual reviews seems to be in full support. There is also this paper which suggests that mining induced earthquakes are quite common. A third paper published in Science last year also suggests that hydraulic fracking can cause earthquakes. ...


14

why would India have so much thorium on it's beaches...? Because monazite. Monazite is a rare earth element phosphate, with the formula CePO4 (where Ce stands not only for cerium, but all of the are earth elements and yttrium as well). It is one of the main ore minerals for the rare earths. It's a very common mineral in granites and similar rocks, and it's ...


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 ...


10

The East Midlands region of the UK is currently experiencing small earthquakes that are believed to be related to mining activities. The British Geological Survey has a page about these events: New Ollerton Earthquake Activity.


7

The main hard rock sources of diamonds are either kimberlites or lamproites. Many kimberlite and lamproite deposits occur as: carrot-shaped, vertical intrusions termed 'pipes' As the term "carrot-shaped" suggests, the general shape of the pipes is conical and when viewed in horizontal cross-sections they are generally quasi-circular. When such ...


7

As stated in the caption for the picture this is an inside view of a potash mine. Mining professionals regard potash, like most coal, to be a soft rock; unlike hard rock such as most metal sulfides. With hard rock mining, the rock is mined by drilling holes and using explosives to break up the rock. The rock is then loaded and transported out of the mine. ...


6

The answer to your question will depend on the type of material and the depth. I will restrict this answer to groundwater withdrawal to focus the discussion. Of course there can be effects from other extractive industries. Groundwater pumping can lead to large scale subsidence, with the Central Valley of California being one of the best described examples....


6

Getting figures on the amount of limestone available is difficult. Apparently "limestone makes up at least 10% of the total volume of all sedimentary rocks". One way to answer your question is by inference. Cement is manufactured from limestone. Current global production of cement is in excess of 3.27 Gt/a and by 2030 it is forecast to be approximately 4....


5

Your last question was easy to answer, this one is more difficult. You could look at correlation and dependence, but you'd be better off looking at variography. That's the easier part of this question dealt with. Most resource geologists do not deal with correlation & dependence, they do variography studies. If you are dealing with a small data set to ...


4

The short answer is, bauxite requires a particular alumina-rich source rock and a specific set of conditions and processes to concentrate the aluminum in a specific order. From the Encyclopedia of Arkansas: The Arkansas bauxite region covers about 275 square miles in the northern part of the West Gulf Coastal Plain and is divided into two mining ...


4

You may want to check this out ESRI open data http://opendata.arcgis.com/ if this is what you were looking for. One another thing is that you might want to contact BLM's Nevada State Office. http://www.blm.gov/nv/st/en/prog/minerals/mining.html They may have the data if they are on the Public lands. I am not sure about the private lands for that.


4

The term "reserves" doesn't mean what most people think it does. A mineral deposit is simply a concentration of a mineral; a reserve is a deposit that is both known and economical to extract. As an example, oil shale and tar sands have both been known for decades, but only recently became oil reserves as improving technology and rising prices made it ...


4

Of course it happens elsewhere! However, I'm not sure there's a specific term, generally. Even in the "montaintop removal" country of Appalachia, there is no more prosaic term for the practice other than MTR. Too bad! It surely deserves a better term! And...despite the complete excising of an entire mountain within the Oquirh mountains, even the Salt Lake ...


4

Your issue is an issue for all types of mining near residential or built up areas, not just manganese mining. The distance that mines should be from built up areas depends on the competency of the ground whether the ground is hard or soft the type of explosive used - more particularly the energy released by the explosives used. This influences the blast ...


3

From the red stain in the water & the rocks in the lower left of the picture it looks like iron ore. Also, the red stain in the water appears to be a colloidal suspension, consistent with minor erosion of a bank rather than an aqueous stain caused by water reacting with sulfide minerals in the bank. The Iron Range occurs in north eastern Minnesota.


3

Start by reading my answer on a different website: https://chemistry.stackexchange.com/a/96630/8083 This is a quick explainer on what "reserves" actually are. Lithium is mined from two main sources: a type of granitic rock called "pegmatite", and brine pools. Pegmatites are rare rocks, and lithium-rich pegmatites are even rarer and you don't find them in ...


3

All coal deposits are different. Coal chemist is highly varied, and the amounts of sulfur and heavy metals with the coal seams varies with each deposit & within seams. This is due to the conditions prevalent when the coal seams were formed. Consequently, the amount of sulfur dioxide emitted when coal is burned, whether in a power station or a mine fire ...


3

Try: Federal Contaminated Sites Inventory as well as Crown Contaminated Sites Database (British Columbia) Orphaned/Abandoned Mine Site Rehabilitation (Manitoba) Abandoned Mines Information System-AMIS (Ontario)


3

Yes. In addition to triggering natural earthquakes, (as pointed out by @hichris123) Mines can also be sources of artificial seismic activities due to mine collapses and/or explosives. Miners will generally try their best to keep their mine shaft stable, but their methods aren't 100% accurate. Sometimes mining in an unstable area or with the lack of support ...


3

Yes, there is much more than enough limestone, by several orders of magnitude, to neutralize the acidity that we are creating - so much so that I am not even going to bother with the back of an envelope calculation. Given enough time (many millennia and possibly several million years) this will happen naturally. However,the process of re-equilibration with ...


3

You should start with the GERM Reservoir Database. Not the easiest to use website, but the most comprehensive. You can look up elemental concentrations in all kinds of "reservoirs", including meteorites. For example, look up CI Chondrites to see the elemental values that are commonly used for REE-diagram normalisation. You can look up by specific meteorites, ...


3

Here is a thermal profile of the borehole: (Source: Fig 5 in Yuri A. Popov, Sergei L. Pevzner, Vyacheslav P. Pimenov, Raisa A. Romushkevich, New geothermal data from the Kola superdeep well SG-3, Tectonophysics, Volume 306, Issues 3–4, 1999, Pages 345-366, ISSN 0040-1951, https://doi.org/10.1016/S0040-1951(99)00065-7.) This borehole is (almost) vertical ...


3

Unfortunately, you intuition about subterranean ground temperatures is incorrect. Basements and cellars do provide cooler conditions to store perishable items because the near surface rock insulates against surface heat. Go deeper however and temperature increases. Near the Earth's surface, within the crust, and away from tectonic boundaries, the rate of ...


2

Table 2 of this paper lists concentrations in CI chondrites of all elements in ppm with variances. This is for one 14kg meteorite that fell in Orgeuil, France in 1868. Check out pages 8-10 for the table and data.


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