A more thorough explanation:

The law of the apex is a principle in mining law that determines who has the right to claim ownership of a tract of mineral land. According to this law, the person who locates the surface covering the outcrop or apex of a mineral deposit has the right to claim ownership of the entire tract of land, along with the defined mining rights.

For example, if a miner discovers a vein of gold that extends from the surface of the ground down into the earth, the miner has the right to claim ownership of the entire tract of land that contains the vein, as well as the right to extract the gold from the vein.

Another example would be if a miner discovers a deposit of coal that extends from the surface of the ground down into the earth. The miner would have the right to claim ownership of the entire tract of land that contains the coal deposit, as well as the right to extract the coal from the deposit.

The law of the apex is important in mining law because it helps to determine who has the right to claim ownership of a mineral deposit. By locating the surface covering the outcrop or apex of a mineral deposit, a miner can claim ownership of the entire tract of land that contains the deposit, along with the right to extract the minerals from the deposit.