Legal Definitions - ad coelum doctrine

The ad coelum doctrine is a common-law rule that states a landowner has ownership of everything above and below their land, from the sky to the earth's core, including all minerals. This rule applies to "hard" minerals like coal but not "fugacious" minerals like oil and gas. It is also known as the rule of vertical ownership.

If a landowner discovers a coal deposit beneath their property, they have the right to extract and sell it. Similarly, if a landowner wants to build a tall structure on their land, they have the right to do so without interference from neighboring property owners.

However, if a neighboring landowner drills for oil and gas beneath their property, they may be able to extract it even if it lies beneath the first landowner's property. This is because oil and gas are considered fugacious minerals and are subject to the rule of capture, which allows a landowner to extract them as long as they can capture them.

These examples illustrate how the ad coelum doctrine applies to ownership of minerals and structures above and below the land. It is an important principle in property law that helps define the rights and responsibilities of landowners.