Ubobtainium was an element that featured in the movie The Core.
This element was a substance that was manufactured by a crystal lattice forged in a tungsten matrix creating a material capable of withstanding great deals of damage to its surface. The greater the pressure or energy enforced onto the element, the metal uses this energy to reinforce the Ubobtainium substance. Theoretically it would be able to withstand pressure underground.
It was perfectly capable of withstanding a new sonic drill technology that was capable of drilling all the way into the Earth's core.