ProductsOverburden Drilling Eccentric Type Balanced Type

Eccentric Overburden Drilling System
The Gamma DTH hammers are produced from the latest technology and highest quality materials under strict quality control.

When drilling in soft and loose ground with scattered boulders, the soil and clay are caved in. This creates drilling difficulty to withdraw the DTH drilling equipment and lowers the drilling speed. To overcome this problem, MAXA manufactures the "Eccentric Type" (EC) Overburden Drill System to enable drilling and lowering the casing simultaneously. This prevents the soil from collapsing into the drilled hole.

The systems are designed to drill the hole diameters bigger than the casing diameter. When reaching the required drilled depth, the DTH hammer and EC Overburden Drill System can be withdrawn from the hole. If the bed-rock level is reached and further drilling is needed, you can simply change the bit to a conventional DTH bit and drill.

We developed the "Eccentric Type" (EC) overburden systems for driving small casings up to 273mm (10.75") O.D. casings. Each system consists of a driver, reamer bit, and locking system. The reamer bits are closed by rotating the system in reverse direction to allow withdrawal of the EC system and DTH drill string when reaching the required depth. The reamer bits can be replaced separately when they are worn out.

Download Datasheet
Eccentric Type Overburden Drilling System Specifications
System Bit Size Outer Diameter of Bit (mm) Applicable Casing (mm) Hammer Shank
Expanded Retracted Outer Diameter Max Wall Thickness
EC115 155 115 139.7 6.3 DHD340A, QL40, SD4, XL4, MACH 44
EC140 190 140 168.3 6.3 DHD350R, QL50, SD5, MACH 50
EC165 219 165 193.7 6.3 DHD360, QL60, SD6, XL6, MACH 60
EC180 240 180 219.1 10 DHD360, QL60, SD6, XL6, MACH 60
EC190 240 190 219.1 6.3 DHD360, QL60, SD6, XL6, MACH 60
EC215 272 215 254 6.3 DHD380, QL80, SD8, MACH 80
EC230 303 230 273 12.5 DHD380, DHD380S, QL80, SD8, MACH 80
EC240 303 240 273 6.3 DHD380, DHD380S, QL80, SD8, MACH 80

Casing Specifications are required upon placement of order. Other sizes can be ordered upon request.

Specifications are subject to change without notice.