The Properties of Coal

• Different types of coal are recognised by their physical and chemical properties.

• These properties can include things as carbon content and ash, the amount of energy it produces, the amount of water present and the density and hardness of the coal.

• These properties are a result of the amount of change the coal has experienced.

The Characteristics of Coal

• Ash and sulfur are important economic characteristics of coal.

  1. • Ash (inorganic material found in coal): this material can be clay or sand deposited at the same time as the organic matter formed the coal.

       1. • High ash contents are undesirable because it builds up in the combustion chamber and must be removed and disposed of constantly.

     • Sulfur in the coal reacts to forms sulfur dioxide then sulfuric acid which is a significant air pollutants 

       1. • Sulfuric compounds means the processing of coal at the furnace therefore must also limited these dangerous gas emictions.

• Common accessory minerals are;

  1. • Quartz.

     • Kaolinite (bleached white clay - used in masks).

     • Calcite.

     • Siderite.

     • Pyrite. 

Rank and Grade of Coal

• The amount of moisture, inorganic impurities and volatiles present determines the grade of the coal.

  1. • CO2, SO2 and N2O

• The grade also depends on on its origin.

  1. • Swamps near sea water, contain sulfates and often produce coals with higher sulfate content than areas of freshwater deposition.

     • Deltas (mouth of the river) may also contain more sediment than coals deposited in deeper, quieter areas of deposition.

• The degree of which the original organic matter has been altered in a coal is known as the rank of the coal.

• When coal is found in thick seems close surface it can be mined on a large open cut methods. Victoria coals seems are over a 150m thick and their is enough to powerd their electric power energy,

Coal Methane Gas

• Coalbed methane, also known as coal mine methane or coal seam methane, is methane that is trapped within coal deposits. During the formation of coal, some methane becomes trapped within the coal seams. This methane can be extracted from the coal through drilling and used as a fuel source. Coalbed methane can also be released during coal mining operations and pose a safety risk if not properly managed.

• The majority of coal we use today was formed during the carboniferous period (350-300 mya ago). There was abundance of swamps with a large amount of ferns and large leafy trees. The environment was rich in oxygen and the seas will filled with large populations of algae.

• Coal formation still occurs today but in much lesser amounts.

• Coal occurs in all states but in WA our main source comes from Collie in the South West.

• Anthracite is slightly metamorphose therefore considered a metamorphic rock.

Geological Setting

• Has a Significant effect on the organic composition, mineral matter content, grade and rank of coal seams.

• 70% of the world's coal reserves are formed in estuarine settings on coastal plains which are covered in seawater.

  • • Collie coal from he collie basin was formed in well away from the sea and  is a high-quality, low-suflur coal.

• Coal forms in bedding ranging form less than 1mm to many metres thick, which are interbedded with layers of shale, siltstone or sandstone therefore coal is commonly found in cyclic sediments sequences, where the coal seems are terminated by the choking of the vegetation by slits/muds during flooding events or due to repeated high-energy conditions produced by meandering river channels.

Environmental Concerns

• Surface mining - removing mountain tops (scaring the topography).

• Toxic chemicals - mercury can leach from waste rock into nearby water ways.

• Acid mine drainage, acid rain and global warming - depends on grade of coal.