Legal Definitions - subjacent support

Subjacent Support refers to the legal right of an owner of surface land to have that land naturally supported by the earth, minerals, or other materials lying beneath it. This right ensures that any activities conducted underground, such as mining or excavation, must be performed in a way that does not cause the surface land to subside, collapse, or otherwise be damaged. It is a fundamental property right that protects the integrity of the surface estate from actions taken below.

Here are some examples to illustrate this concept:

• Underground Mining Operations: Imagine a large mining company that owns the mineral rights beneath a rancher's property. The rancher owns the surface land, which includes pastures and a farmhouse. As the mining company extracts coal or other minerals from deep underground, they must ensure their operations do not compromise the stability of the land above.

  This illustrates subjacent support because if the mining activities cause the ground on the rancher's property to sink, crack, or collapse, leading to damage to the farmhouse or pastures, the mining company would have violated the rancher's right to subjacent support. The rancher's surface land has a legal right to be supported by the earth and minerals beneath it, and the mining company is obligated to prevent subsidence.

• Construction of a Deep Underground Tunnel: Consider a city planning to build a new subway tunnel that will run directly beneath a row of historic commercial buildings. The tunnel requires extensive excavation several stories below the surface.

  This illustrates subjacent support because the owners of the commercial buildings have a right to subjacent support. The city, in excavating for and constructing the tunnel, must implement engineering measures to ensure that their activities do not weaken the ground beneath the buildings. If the construction causes the buildings' foundations to crack, walls to shift, or the structures to settle unevenly, the city would be liable for infringing upon the property owners' right to subjacent support.

• Excavation for a Neighbor's Basement: A homeowner decides to build a new house with a very deep basement on a lot adjacent to an existing, older home. The excavation for the new basement extends significantly below the foundation level of the neighboring house.

  This illustrates subjacent support because the owner of the older home has a right to subjacent support from the land beneath their property. The new homeowner, while excavating for their basement, must take necessary precautions (such as installing shoring or underpinning) to prevent the soil beneath the neighboring house from shifting, eroding, or collapsing into the new excavation. If the excavation causes the adjacent home's foundation to crack or its walls to settle, the new homeowner would be responsible for violating the neighbor's right to subjacent support.