# Coal Tonnage Calculator Online from Area, Thickness and Specific Gravity (Estimating Coal Tonnage)

You can calculate the "total coal tonnage in a property" using the online calculator included in this page. The equations used for the calculation of coal tonnage are explained in details. This calculator report "IN PLACE COAL TONS" without applying any mining recovery factor or plant loss. This online coal tonnage calculator also gives you the "in-place coal tons per acre foot" values from the specific gravity of the coal seam. For bituminous coal 1800 tons per acre-ft is commonly used. However, if you have laboratory data for the specific gravity of the coal seam, you can derive a better number for the coal tonnage per acre-feet.

Required Parameters that you must know:
• Area - Usually in square feet or in acres.
• Coal seam height - usually in feet or in meters
• Specific gravity of coal seam - unit-less, usually from lab analysis. (specific gravity - The ratio of the weight of an object in air to the weight of an equal volume of water. The specific gravity1 of bituminous coal ranges between 1.1 5 and 1.5 depending on rank, moisture content, and ash content, and averages 1.32.)
1. Equation for the determination of Tons per acre-foot is as below:
Coal tons per acre feet= (62.4 lbs/cubic feet x 43,560 ft3 natural resource/acre x Specific Gravity)/2000 lbs/ton

2. Equation for the determination of Coal Tons is as below:
Coal tons = Acres * Coal thickness* (coal tons per acre feet)

Conversion factors:
• Specific gravity of bituminous coal = 1.32
• 1 ft3 of water = 62.6 lbs
• 1 acre = 43,560 ft2
• 1 ton = 2,000 lbs
Input the required parameters:
Area in acres:                           Note: If you have area in square feet, divide it by 43,560 to convert into acres (1 acre = 43,560 square feet)
Thickness of coal seam in feet: Note: If you have thickness in meters, multiply by 3.2808 to convert into feet (1 m = 3.2808 feet)
Specific Gravity of coal seam   unitless, enter average value from lab data.
Because specific gravity varies with rank, different ranks of coal have different conversion factors.
• Anthracite: specific gravity = 1.47, so the conversion factor is 2,000 tons/acre foot
• Bituminous: specific gravity = 1.32, which is 1,800 tons/acre foot
• Subbituminous: specific gravity = 1.30, which is 1,770 tons/acre foot
• Lignite: specific gravity = 1.29, which is 1,750 tons/acre foot
Similar calculations for other mined minerals yield the following results:
• Limestone = 3600 acre-lt.
• Sandstone = 3300 acre-ft.
• ClayIShale = 3250 acre-ft.
• Sand~Gravel = 2400 acre-ft.
• Salt = 2950 acre-fi.
More resources: http://www.uky.edu/KGS/coal/estimatingTons.htm