- Coal
- How coal is mined
- Specification
|
| Coal is a fossil fuel, like oil and natural gas, formed from plant remains from millions of years ago. As plants died layers of sand and mud covered their remains, forming a soggy, sponge-like material called peat. Over several thousand years, the sand and mud compact the peat beneath the earth's surface where increased pressure, heat and chemical alteration turned the peat into coal. Coal deposits can be traced to different time periods, but most deposits are from more than 300 million years ago |
How Coal Is Mined
Coal is mined either in open pit mines (on the surface of the earth) or in underground mines.
Once coal seams are found, mining teams work to estimate the quantity, quality and depth of coal in the area. In open pit mines, the topsoil is first carefully removed and stored where it can be used to restore previously mined areas into thriving ecosystems.
Blasting is then used to break through rocks and other overburden. The rubble and overburden is removed from the mine by large machines called draglines or shovels. Additional blasting is used to free the coal, which is then loaded onto haul trucks and transported to coal handling facilities where it is sized, blended and loaded into trains according to customer specifications. Finally, the coal is taken to power plants, mills or sold in international trade.
Once an area has been mined, the land is reclaimed and restored using topsoil taken from the original site, or from a nearby mine
Types OF Coal
Coal classification is based on the amount of carbon in the coal and how it responds to increasing heat and pressure beneath the earth's surface. Coal is classified into four categories:
Lignite
Subbituminous
Bituminous
Anthracite
Clean Coal Technology
For coal to remain a valuable long-term energy source, coal producers and users need to minimise the impact of burning coal and reduce the amount of carbon dioxide emissions from power plants.
Technology breakthroughs are required to find new ways of using coal that will supplement existing efficiency improvements. These initiatives range from improving the performance of existing boilers, to promoting the adoption of more efficient, advanced boiler designs, to coal gasification and, eventually, to carbon capture and sequestration. |
| Australia Coal Test |
| Bases |
As |
Air |
Dry |
Dry Ash |
| |
Received |
Dried |
|
Free |
| |
|
|
|
|
| Parameter |
|
|
|
|
| Total Moisture |
11.0 |
|
|
|
| Inherent Moisture |
3.0 |
3.0 |
|
|
| Ash |
14.7 |
16.0 |
16.5 |
|
| Volatile Matter |
28.4 |
31 |
32 |
38.3 |
| Fixed Carbon |
45.9 |
50 |
51.5 |
61.7 |
| Total Sulphur |
0.6 |
0.65 |
0.67 |
|
| Phosporus |
0.03 |
0.03 |
0.03 |
|
| Carbon |
|
|
70.58 |
84.5 |
| Hydrogen |
|
|
4.42 |
5.29 |
| Nitrogen |
|
|
1.64 |
1.97 |
| Oxygen |
|
|
6.19 |
7.4 |
| Chlorine(ppm) |
|
300 |
|
|
| Flourine(ppm) |
|
90 |
|
|
|
| |
| Calorific Value |
| Gross (kcal/kg) |
5982 |
| Nett( kcal/kg) |
5692 |
| Ash Fusion Temperature Degrees C |
|
| Initial Deformation |
1350 |
| Spherical |
>1600 |
| Hemishherical |
>1600 |
| Flow |
>1600 |
| H.G.I |
50 |
| Abrasion Index |
13 |
| Sizing: |
|
| Less than 500mm |
100% |
| Less than 2mm |
30% |
|
| |
| ASH ANNYSIS (Typical) |
| Silicon as SiO2 % |
64.1 |
| Aluminium as Al2O3 % |
26.1 |
| Iron as Fe2O3 % |
5.06 |
| Calcium as CaO % |
0.81 |
| Magnesium as MgO % |
0.48 |
| Sodium as Na2O % |
0.22 |
| Potassium as K2O3 % |
0.68 |
| Titanium as TiO2 % |
1.44 |
| Manganese as Mn3O4 % |
0.05 |
| Sulphur as SO3 % |
0.28 |
| Phosphorus as P2O5 % |
0.59 |
| Total |
99.8 |
|
| |
| Indonesia Steam Coal Typical Specification |
| Total Moisture (ARB) |
14% Rejection Above 16% |
| Inherent Mositure (ADB) |
9.00% |
| Ash Content (ADB) |
16% Rejection Above 17% |
| Volatile Matter (ADB) |
42.00% |
| Fixed Carbon (ADB) |
By Differences |
| Total Sulphur (ADB) |
1% Rejection Above 1% |
| HGI |
45.00% |
| GCV |
6300Kcal/kg Rejection Below
6200Kcal/kg |
| Size Ratio |
< 0-50mm - 90% |
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