How can I find out how much coal I have on my property?
Do you own the mineral rights?
In Kentucky, ownership of property may be separated into surface rights, timber rights, mineral rights, etc. If you do not own coal mineral rights, then you do not own the coal on your property. On the other hand, you may have mineral rights to coal on someone else's property. You should know the type of ownership you have before you proceed any further.
Where is your property?
Next, you must determine whether or not your property is within one of the two coal fields. The coal fields are composed of Pennsylvanian-age rocks. If your property is not situated on coal-bearing rocks, you are not going to have coal on your property. Go to the Online geologic map service of Kentucky to see if your county is in one of the coal fields. You can zoom into your county using the zoom tool, or you can go to the tools bar, and use “zoom to a location or area” and use one of the options (county, 7.5-minute quadrangle, etc.) to zoom to or close to your property. You can also use the paper 7.5-minute topographic and geologic maps to locate your property.. The geologic quadrangle maps (also called GQs) are at the same scale as the topographic maps. The geologic map will indicate whether your property is on Pennsylvanian rocks or not.
What coal beds do you have on your property?
The online geologic map service and 7.5-minute geologic quadrangle maps will give some indication about the major coal beds that cropped out at the surface on your property (at the time the map was made), although not all of them will be mapped. Deep coal beds will not be indicated on the GQs. To determine if coal beds beneath the surface which are not mapped on the GQs, or occur beneath the level of surface drainages subsurface coring records are needed. The locations of publically-available borehole records are shown on the online geologic map service or can be searched for under coal data.
Calculate coal reserves for each coal bed
This is the complicated part; most people would hire a registered consulting geologist or registered mining engineer for this. The process is explained here, in simplified terms. Each step is done separately for each of the coal beds under consideration. The first step is to gather as much coal thickness information as possible for the target coal bed. Information may be obtained from the Kentucky Geological Survey’s coal thickness database, KGS borehole database, files of local coal companies, and neighbors and by examining outcrops, digging out the coal, and possibly drilling boreholes (drilling can be paid for by interested companies). After coal-thickness data are gathered, a map showing coal-thickness trends (isopach map) is constructed for the target bed. Property lines and the outcrop lines for the target coal bed are added to the map. Next, the area for each thickness class must be measured (generally in acres). This process is called planimetry. Planimetry measures the area of the property. With the area and thickness known, a volume of coal can be calculated, and from this volume, a total tonnage can be derived. Planimetry can be done by hand using several methods, but the most accurate is with a mechanical device called a planimeter. Planimetry can also be done accurately by a computer using special software. From the calculated areas and the projected thickness trends, a gross reserve estimate can be calculated.
The gross reserve estimate is a volume calculation based on a conversion factor for bituminous coal: 1,800 tons for every acre for every foot of coal. To estimate the tons of bituminous coal on a property, the formula is:
Acres × Coal thickness × 1,800 tons/acre-foot = Tons of coal on your property
Acres = the number of acres underlain by a coal bed
Coal thickness = the average coal thickness in decimal feet for that area underlain by coal.
For example. if you have 4 acres of property underlain by a coal bed, and the coal bed thickness is 5.2 feet, then, 4 × 5.2 × 1,800 = 37,440 tons of coal.
More about this calculation: How it is derived from coal density (specific gravity) and area
Many other factors must also be examined to determine what the coal is worth: quality, mineability, transportation, available market, etc.