Coal lecture 2 Flashcards
Is coal new?
No, coal has been burning for 1/2 a century, with frequent use from the C12th and since the 16th century in the UK. Coal was mined in the North East eg. Newcastle.
- it drove the industrial revolution
Who was the largest extractor of coal?
UK was by far the largest extractor and user of coal up to the first world war (1914), when the US were ahead for the 1st time.
History of UK coal production?
bell shaped curve in terms of usage, this isn’t because we have run out of coal, we now know about coal in the UK but its not economically extractable, cheaper to export, so the UK coal production system is largely non-economical.
- dips in UK coal production show world wars occurring
What is one of the leading causes of global warming?
- Carbon emissions from burning coal are one of the leading causes of global warming.
- Acid rain, from sulphur emissions is almost entirely due to coal burning.
What forms does coal come from?
1) PEAT (not coal)- partially decayed plant matter in swamps and bogs; low heat content - starts with terrestrial plants being laid down under wet conditions and gradually becomes compressed (peat).
2) Heat and pressure is then applied to create Lignite (brown coal)- it has low heat content; low sulphur content; limited supplies in most areas (lots of water, low carbon content and low heat value).
3) Heat and pressure is applied to create Bituminous (soft coal)- it is extensively used as fuel because of its high heat content and low large supplies; normally has a high sulphur content
4) Heat and pressure is applied to create Anthracite (hard coal) which is highly desirable because of its high heat content and low sulfur content; supplies are limited in most areas. (‘black coal’ high value- used for burning in power stations as its a cleaner coal
What is coal composed of?
Coal is composed of primarily of carbon, along with variable quantities of other elements, chiefly hydrogen, oxygen and nitrogen.
What are the constituents of coal?
made up of moisture, voltatile matter (flames that shoot off when you burn with coal), fixed matter and ash.
- also other contaminents eg. mercury content in coal
- lead, arsenic, cabium in coal so heavy metals that have damaging properties to health.
- get ash when you burn coal so always have waste products.
By mass:
- nitrigogen 1%
- sulphur 1%
- oxygen 5%
- hydrogen 5%
- Carbon 88%
How can you get gas from coal?
if you heat coal with the absence of air then you can separate off components, you can get coal gas which is extremely dirty as it contains impurities but if you clean that up you get ‘town gas’ which is piped into towns and has low pressure containing these gas works ( which are large gas pipes that expand& contract).
When you go through this process of heating up and getting rid of violities, you get a very pure forms of carbon called ‘coke’ which we can use for the metal industry + get useful products as you can seperate sulphur, ammonia is an industrial precuser.
- can get coal tar ‘coal tar soap’ from this process and industrial use eg. light oil fractions.
What is deep mining?
- accounts for 40% of US coal mining
2 ways to get coal out of the ground- dig it up and create spoil heaps, which creates environmental issues
EG. the Welsh village of Aberfan disaster - a spoil heap became distablised so slipped and killed 116 school children and 28 adults.
1966- took 5 mins for coal to slide down mountain and engulf school+ several houses.
Environmental problems of deep mining
- Acid mine drainage from mines and waste piles has polluted thousands of km of streams.
(coal deposits tend to be associated with sulphur present in the minerals Ironforate - if you oxidise that you get sulphur acid. To oxidise you dig it up and expose it to the air. Also leave the mines open to fill up with water and to oxidise, you get sulphuric acid that is problematic as it is toxic and also immobilises aluminium which is toxic to the Eco-system. - land subsidence can occur over mines
- coal fires in underground mines either naturally caused or are deliberately set ( generating coke+ realising gases from coal mines).
What is deep mining?
UK has gone from having lots of coal sources to not exploiting them at all, one reason for this automated process so that to make this work, machine goes along (big stream of coal) collects coal on a conveyebelt and is taken out. A lot of UK coal is in small streams so is not economically viable to do this process.
- impacts on human health- direct contact, explosions, suffocation & long term respiratory diseases.
What is opencast mining?
IMPACTS- environmental controversy is mountain topping, taking the top off mountains to extract coal but as a result there is huge landscape modification.
- associated problems of acid run-off. Once you have exposed the seams, process of sulphate is a natural process but happens much quicker when you modify things by mining.
What is strip mining?
- Technique known as “mountain top removal”
- Strip-mining levels tops of mountains and fills valleys with mining waste
- flood hazard increases as valleys filled with mine waste and toxic waste is stored behind coal waste sludge dams
- also produces voluminous amounts of coal dust
EG. Appalachian Mountain’s of West Virginia
Location of main coal deposits
major deposits found in US, Russia &China
- Australia major resource, very pure types so has a high value. Highest value coal is imported from Australia.
- have to seperate out lignite, brown coal which is less valuable.
How much coal have we got?
Interested in how much we have left eg. PROVEN RESERVES = economically extractable resource
- USA HAS 28.9% of the worlds reserves compared to UK having just 0.02% (Everett et al. 2012).
- China has huge reserves, nearly 1/2 of world production of coal is occurring in China but because of low production rates it gives a small reserve in comparison so becomes a big driver for Chinese energy policy to look for alternatives.
