The spirit veins rooted above the earth veins might also slowly disintegrate and vanish due to the scarcity of geographical advantages, failing to meet the conditions for their existence.
Therefore, although earth veins are lengthy and profound, an excessive depletion can ruin an entire region.
Although it could recover in the future, that period would be counted in tens of thousands of years.
It was akin to mortgaging the future.
Of course, given the depth of the earth, even an Earth Immortal formation fully extracting from the earth veins each for more than a hundred years, would still struggle to deplete them entirely.
This sustainability is still quite reliable.
This is also why many formations choose earth veins as their energy supply.
The second type, the energy of spirit veins, is the purest and can maximize the power of the formations.
