Vertical/Horizontal/Inclined Core Drilling
A common drilling method is telescopic dry core drilling in granular soil. This method usually uses a single tube core barrel. During each cored section, the entire drill rod is removed and reinstalled to extract the drill core. These near-surface boreholes are drilled with the help of casings that interlock to support the borehole wall. Depending on the geological situation and the drilling equipment, sections of approximately 10 to 25 meters can be drilled per pipe section. The casings are removed once drilling is completed.
This method enables dry core drilling with an initial diameter of 419 millimeters. With the telescopic casings commonly used at Stump-BTE Bautechnik AG and a depth of approximately 10 to 25 meters per pipe section, filter wells can be constructed with the corresponding diameters and depths.
Wire Line Core Drilling
Core drilling by using the wire line core method is one of the specialties of Stump-BTE Bautechnik AG. This drilling method is mainly applied to explore deeper underground. Wire line core systems are similar in structure to double-tube core barrels. Here, however, the inner system can be hoisted separately from the outer system using a cable winch. With double- or triple-tube core barrel systems, the mechanical impact on the core is lower than with a single-tube core barrel. The core is protected against the mechanical impact of the circulating flush by the inner tube of the core barrel. The flush is channeled through an existing annular space between the inner and the outer system. Flushing additives make it possible to maintain the core in its original condition. Wire line core systems must be driven with a special rod in order to enable the core in the inner system to be recovered via the cable. Usually, after the core is extracted, the inner tube is reinserted into the rod string by gravity. Pumpable systems are available for inclined drilling.