A more thorough explanation:

Subsurface interest refers to a landowner's right to the minerals and water that are located below their property. This means that the landowner has the legal right to access and use these resources as they see fit.

For example, if a landowner discovers oil or gas beneath their property, they have the right to extract and sell these resources for profit. Similarly, if there is a natural spring or aquifer beneath the land, the landowner has the right to use the water for their own purposes.

It's important to note that subsurface interest can also be granted or sold to another party. For instance, a landowner may choose to sell the mineral rights to a mining company, allowing them to extract resources from the land in exchange for payment.

Overall, subsurface interest is an important aspect of property ownership, as it allows landowners to benefit from the valuable resources that lie beneath their land.