Drilling 9½ Miles Into The Earth’s Core

Press, Volume CVI, Issue 31081, 9 June 1966, Page 5

Drilling 9½ Miles Into The Earth’s Core

(N.Z.P.A.-Reuter) MOSCOW. Soviet scientists and engineers are planning to start work later this year on drilling a 9] miles hole down towards the earth’s core. They hope by this means to learn some of its longkept secrets.

Working from dry land on the Kola peninsula, adjoining northern Norway, inside the Arctic Circle, the drillers expect to penetrate well into the earth’s basaltic layer in five or six years.

The Kola Hole, part of the International Geophysical year, is seen as complementary to the United States Mohole project, which is attempting to reach the edge of the earth’s innermost mantle from a sea-based centre near Hawaii. The Mohole is so named because it is aimed at penetrating the Moho, or Mohorovichich, layer which separates the basalt from the mantle. Drilling from close to the Equator, the United States scientists have to sink the drill about 3 miles to the sea bed before they can start penetrating into the basalt.

But the Soviet drill will have to drive through nearly 5 miles of granite before it reaches the Conrad layer, which separates the top-laying granite from the basalt. The Kola Hole will be considerably deeper than the Mohole. From Hawaii, the Moho layer is only about 6 miles down. Solving Problems Beginning from the earth’s far north, the Soviet drillers will have to penetrate much further to reach the mantle, which forms the centre of the planet like the yolk of an egg, even if they touch it at all. Dr. N. Khlebodarov, an

engineer working on the project wrote recently that many of the problems of the earth and the neighbouring planets would remain unsolved until the areas, beneath the Conrad layer and the even more mysterious Moho layer give up their secrets. Writing in the weekly magazine, “Nedelya,” he said that the Soviet Union is planning a whole series of 9-mile holes. The one at Kola is the first.

Another project is the Soviet Union's own sea-based Mohole, in the Pacific Ocean. The Kola peninsula was chosen for the first hole, Dr. Khlebodarov explained, because drilling could start direct into the granite layer, which outcrops above ground on Kola.

Elswhere, the granite layer, which lies immediately below the earth’s surface on dry land, is topped by sedimentary rocks, the hardness of which, according to Dr. Khlebodarov, would have pre-

sented a insurmountable barrier to even the most modern drilling equipment. Methods Used

The Soviet engineers have chosen a turbine method of drilling, with a hydraulic motor turning the drill ait the drilling face. Aluminium and titon were chosen as the best metals for the drilling tubes, because steel tubing of such a length would have broken under its own weight, Dr. Khlebodarov wrote.

However, he added, the greatest problem which the drillers face is how to lower and raise the worn-out drills. Using normal methods, the 9-mile hole would take 10 years to complete. In normal drilling, the pipes have to be raised not only to the surface but to the same height above it to be dismantled on a drilling tower one by one, laid down, and then reassembled when the new drill is being lowered.

Dr. Khlebodarov said that this problem has been solved by telescoping several operations and make the whole process an uninterrupted one. This will cut down the time for the project by four to five years.

Ordinary mining equipment will be used to drill as deeply as possible. After Chat the specialised gear will take over.

By late 1971, Soviet scientists hope to be analysing the first samples extracted from nine miles down inside the earth.