Wegener also noted that the continents move up and down to maintain equilibrium in a process called isostasy. As an example he cited the sinking of Northern Hemisphere lands under the weight of continental ice sheets in the last ice age, and their rise since the ice melted some 10,000 years ago.
Drill that is fitted with a Pipe provides effective connection to the rig surface equipment or application with the bit and the bottom hole assembly for the purpose of pumping the Drill fluid to the bit.
Drill bits used with the impact function of these drills are dedicated masonry or concrete bits with flattened, tungsten carbide tips. An impact drill may be used to drill into a variety of hard, aggregate materials such as brickwork, cement, and concrete.