### Question
Can you define what coal seam means?


### Answer
**Coal seam** is defined as the following in *42 U.S.C. § 13368*:

> any stratum of coal 20 inches or more in thickness, unless a stratum of less thickness is being commercially worked, or can in the judgment of the Secretary of the Interior forseeably [3](#13368_3_target) be commercially worked and will require protection if wells are being drilled through it

#### Citation:
  - *42 U.S.C. § 13368*
  - Heading: **CHAPTER 134-ENERGY POLICY > SUBCHAPTER VI-COAL > Part C-Other Coal Provisions**

