Quite simply because there is no easy way to do it. Working at depth brings with it problems that current technology can't address easily.
water power,mineral and deposits
Mineral deposits.
They are called mineral deposits or precipitated minerals.
internal piping has mineral deposits
These minerals are dissolved in the water while it moves through the earth.
One of the most common issues with mineral deposits people experience is the build up of calcium deposits in the body. One alternative healing method for removing the mineral deposits is to drink a mixture of honey, apple cider vinegar, and water until the deposits are removed from the body. The mixture helps to breakdown the excess calcium.
They are called mineral deposits or precipitated minerals.
Nearby water supplies dry up
Mineral deposits from use of hard water.
Ground water, mineral deposits, and stalactites
Stalagtites are formed by mineral deposits by water.
Mineral deposits are formed when ground water that contains dissolved minerals are cooled or has evaporated. Some of these mineral deposits are iron ions, magnesium, and calcium.