There are working salt mines beneath the wheat fields of central Kansas.

In a series of rooms, 650 feet below the earth's surface, a company maintains more than a million cardboard boxes of records for 15,000 individuals and business firms. The rooms are in an abandoned mine.Why store materials here? Geophysical computers are generating more data and more room is required to store it. One firm, Phillips Petroleum, has 144,000 seismic tapes in one mine and another 190,000 in Oklahoma, which together would make a stack more than 5 miles high.