Methods of excavation

The two main types of mining operations are surface mining and underground mining. Sur­face mining as the name indi­cates is about locating coal at the surface! Obvious you would say! Well, actually even this has two categories, one being the stripping or open cast mining and the second being hill slope boring

Open cast Mining

Stripping or open cast mining

• Open cast mining or stripping is well suited for areas where coal seam lies at or near the surface not more than 60m deep.
• The seam should be more or less hori­zontal with the prerequisite of a thin and soft overlying strata, very much like a crumbly black current pie.
• This is the easiest way to mine, as it hardly disturbs the under­lying stratas, although large tracts of agricultural land may be devastated.
• Modern conser­vation techniques have now re­stored areas of open cast min­ing, especially in the Appala­chian areas and Australia.

Hill Slope Boring

• Giant sized augers (boring in­struments) are used to dig out coal on hill slopes. These augers can reach as far as 105m below the ground.

Underground Mining

Drift or Adit Mining

• A tunnel called drift or adit is cut into the coal bearing stratum.
• This type of mining operation is undertaken in hilly areas with a slightly inclined or hori­zontal coal seam with a thick over burden.

Slope Mining

• This is practised in areas with steeply tilted coal seams or where coal is below a thick overburden.
• An inclined tunnel known as slope is constructed and a con­veyor belt or a cable car is used for bringing out coal through the tunnel.

Shaft Mining

• This method of mining is used for reaching deep -seated seams (305m to 1525m below the surface).
• Vertical shafts are sunk to reach the coal bed, and a net­work of galleries is dug under­ground. Lifts or box like cages are used to access the mine.
• Often explosives are set in the coal face for loosening coal into lumps.
• Shaft mining is the most ex­pensive of the mining meth­ods because of the overhead costs of ventillation, lighting, water supply and underground haulage.
• The safety in the mines has to be ensured by providing proper ventilation so that the fire accidents don't occur, which would also help reducing the health hazards miners face.
• They should be aided by better geological in­formation pertaining to the seasonal movement of the wa­ter tables in order to equip them against the danger posed by the crushing in-flow of wa­ter.
• There should be efficient pumping stations to pump the water out of the mines.
• The mining company must take precautions against such possibilities as gas poisoning, explosions, floods and the collapse of tunnel roofs.

Distribution

USA

• Coal occupied a very significant role in the development of heavy industrial centres in the USA like Pittsburgh, Detroit, Chicago etc.
• Largely, the coal-producing regions are concentrated in the eastern part of the country and comprise the states of Pennsylvania, Virginia, Kentucky and Ohio.
• Important coalfields of this region include the Appalachian coalfield especially the regions like Pittsburgh, Alabama, Tennessee, the Allegheny plateau, and Grand Kanawha. Pennsylvania produces half the world's anthracite (from the Lehigh, Schuylkill and Susquehanna valleys) while the Appalachian field is the centre of bituminous coal.
• In the central, western and south part of the US the coalfields are scattered as opposed to the eastern part.
• Important collieries of the central regions are situated in Illinois. Missouri, Ouachita Mountains of Arkansas and Oklahoma.
• In the western US the Rocky Mountain region has the largest coal reserve of the US but it is not fully exploited.
• Important coal reserves are located in Utah, Montana, Colorado, Dakota etc. In the southern US, coal deposits alongwith the oilfields are situated mainly in Texas.
• Interestingly all the coal mines in the US are privately owned.

Russia

• Before the break up of the USSR in 1991, the Donetz basin or the Donbas situated near the Black Sea in Ukraine was the most important coalfield of USSR.
• However, in the present day Russia important coalfields include the Tula coalfields near Moscow, which mainly produces lignite and the Kuzbas or Kuznetsk coalfield near the Ural Mountains.
• In the Siberian region of Russia lie large but untapped reserves of coal, especially in the Tungus and Lena basins.
• Other coalfields include the Pechora, Vorkuta in the northern region, Cheremkhovo in Siberia and Sakhalin islands in the eastern most part.

UK

• UK was the birthplace of the coal based industrial revolution occupying the leading position as the producer as well as the exporter of coal in the world in the 8th and 9'h centuries.
• Though, unlike the U.S the coal mining in the U.K is nationalised, nevertheless coal has been the major source of energy for the ship building industry in Glasgow, cotton textile industry of Lancashire, iron and steel industry of Midland and South Wales and automobile industry at Coventry.
• However, coal mining in U.K is being discouraged because of the high costs involved in it.
• This is so because unlike the wider and expanded coalfields of the U.S, those of the U.K are limited in extent and have a faulted topographical formation, which escalates the mining and maintenance cost of coal

Europe

• Europe's richest coalfield is the Ruhr-Westphalia region in the Rhine basin.
• The second important coalfield is the Saar coalfield.
• In addition there are Saxony coalfields, and lignite deposits at Cologne and Bavaria.
• The Ruhr—Westphalia coal complex is the industrial base of Germany.
• The coal and iron ore reserves located in close proximity to each other has aided the establishment of basic industries of iron and steel as well as other heavy industries.
• The industrial towns that grew up around Ruhr coal-field are Essen, Solingen , Remscheid, Wuppertal, Cologne and Dusseldorf.
• There are smaller coal fields at Aachen and Lignite fields at Bavaria and Cologne.
• Apart from Germany other important producers of coal in Europe are France, Belgium and Poland.