Overburden Drilling System

Sysbohr design and manufacture first-class drilling systems, tools, and accessories for the construction and geothermal industries. Manufactured in Fulda by Sysbohr, products are distributed worldwide through an excellent supply network. In-house specialists and consultants ensure that the requirements of the customer are fully met. Flexibility within the design and manufacture of products is one of the most important features.

Overburden Drilling Systems

The name “Overburden Drilling” results from the composition of the earth‘s crust. The bedrock is difficult to reach due to loose layers of earth consisting of sand, gravel, boulders combined with loose ground and other deposits. All these formations s under the umbrella term “Overburden”, which overlies the bedrock.

Certain drilling processes make it necessary to support a borehole wall with tubes. Based on the requirements and circumstances at hand, different drilling variants are useable. Including pure rotary drilling with a rotary head or rotary percussion with a hydraulic drifter or with a double head drilling unit rotary / rotary or rotary/rotary/ rotary-percussion. Please see below the different variants in detail.

D 114.3 - D 244.5 With Rotary Head

The system shown here has two rotary units that can rotate opposite to each other. The rods counter-rotate independently. Flush air or water down the center of the inner drill string to the end of the drill hole. It discharges the cuttings in the annuls between both rods through the flushing holes above. The slide of the rotary drives allows the inner rod to move ahead the outer rod and is retractable. The pilot effect of the inner rod gives better alignment. So, these systems are especially suitable for horizontal drilling, e.g. injection drilling for tunneling and exploratory drilling.

Depending on the ground conditions, the drilling can be made either with rotary drill bits or DTH-hammers. Another possible way to discharge the cuttings is to use auger drill rods, especially, if flushing with air or water is not possible with this system to drill the whole drill string in together, the drilling is made separately. First the outer casing, followed by the inner string.

Overburden Drilling With Double Head Drilling Unit
skizze modal of a drilling system underground
illustration of a Rotary Head DTH hammer underground

D 88.9 - D 152.4 With Hydraulic Drifter

Certain drilling processes make it necessary to support the wall with tubes. The system shown here gets power by a hydraulic hammer, which turns and strikes the whole drill string from above, consisting of an outer and inner rod. Flush air or water down the center of the inner drill string to the end of the drill hole. It discharges the cuttings in the ring space between both rods through the flushing holes above. This drilling system is for relatively shallow depths.

Overburden-Drilling with Hydraulic Drifter
modal of a rotary drill
illustration of a Rotary Head DTH hammer underground
skizze modal of a drilling system underground

D 114.3-D 219.1 With Double Head Drilling Unit (Rotary/Rotary)

Certain drilling processes make it necessary to support the wall with tubes. The system shown here has two rotation units which can be moved opposite to one another. The rods are counter-rotating independently. Air or water is flushed down the center of the inner drill string to the end of the drill hole. It discharges the boring in the ring space between both rods through the flushing holes above. The slide of the rotary drives allows the inner rod to move up and down relative to the outer casing. 

The pilot effect of the inner rod gives better alignment. So, these systems are especially suitable for horizontal drilling, e.g. injection drilling for tunneling and exploratory drilling. Depending on the ground conditions, the drilling is made either with rotary drill bits or DTH-hammers. Another possible way to discharge the boring is to use auger drill rods, which are especially suitable for deep drilling with eccentric drill bits. This system is also convenient, if flushing with air or water is not allowed for construction or environmental reasons.

Overburden drilling system
illustration of a Rotary Head DTH hammer under ground
illustration of a Rotary Head DTH hammer underground
Auger Drilling illustration

D 114.3 - D 177.8 With Double Head Drilling Unit (Rotary/Rotary-Percussion)

Certain drilling processes make it necessary to support the wall with tubes. The system shown here has two heads which can be moved opposite to one another, rotary (outer rods) and rotary-percussion (inner rod). The rods are counter-rotating independently. 

Air or water can be flushed down the center of the inner drill string to the end of the drill hole. It discharges the cuttings in the annulus between both rods through the flushing holes above. The slide of the rotary drives allows the inner rod to move up and down relative to the outer casing. The pilot effect of the inner rod gives better alignment. So, these systems are especially suitable for horizontal drilling, e.g. injection drilling for tunneling and exploratory drilling.

Overburden drilling system
illustration of a Rotary Head DTH hammer under ground
illustration of a Rotary Head DTH hammer underground