GEOTECHNICAL ENGINEERING LTD.doc

GEOTECHNICAL ENGINEERING LTD.

Equipments and sampling methods

Augerboring;with 65 mm, 110 mm diameter;Auger-bit: soft to medium stiff deposits.

Hollow Stem Auger - HSA boring;with 258/168 mm and 200/90 mm outer/inner diameter;

Casing and sampling in one technology, this is up to date geotechnical and environmental sampling method.

The HSA works as a casing, suitable for disturb or undisturbed sampling, and water sampling even in noncohesive soil conditions.

At environmental projects there is no possibility for soil samples to contact with upper layers. Combined with Split Tube Barrel soil samples do not contaminated by underground water.

Simple wall, dry core barrels;

Thin Wall Sampler - Shelby type;Core diameter: 72 mm.

This sampler, often reffered to as a Shelby tube sampler, is the simplest and most widely used of the in situ quality samplers. We combined it with HSA technology, in soft, plastic soil conditions. The length of the sample between 0,2 - 0,5 m.

Split Tube Barrel;Core diameter: 60 mm.

All-purpose sampler used for visual classification, contamination content and moisture determination. The split barrel permits removal of the sample as it is taken from the ground in a plastic tube. In noncohesive soils the sampler is used with a flap valve, light duty or heavy duty basket trip. We use it with HSA technology in medium stiff to stiff soils, length of the sample between 0,2 - 0,5 m.

Simple wall, dry core barrels in 101/95 mm and 114/100 mm large diameter;It takes large diameter core samples in medium stiff to stiff soils, in 0,4 m to 1,0 m length. We installed it for the URB 2A2 RC drilling rig because of the higher bottom pressure, pulling force and even for higher torque.

Rotary wash drilling;

In the case of rotary wash drilling we use polimer contributions (GS PREMIX 550; LUBTUBE).

Full face drilling;between 65 mm and 260 mm for waterwell construction, geophysical logging purposes;

Continuous core drilling with T6 double wall barrel;This technology takes large diameter (101 mm) core samples in 1,5 m length pieces.

We use this for geological and raw material research projects, for visual classification and description of strata with exact layer borders.

Continuous Wire Line core drilling with triple wall core barrels;

Mazier automatic core barrel;This technology takes large diameter (101 mm) core samples in 1,5 m length pieces.

Using triple wall core barrel permits removal of the sample as it is taken from the ground, guaranteed the 'in situ condition of the core. Thats why these samples in addition good for large diameter geotechical laboratory tests beyond geological purposes.

The third, inner tube made of plastic and

continuously cover the sample.

The Wire Line system allows that only the core barrel (second and third tubes) have pulled out to the surface after 1,5 m core drilling, while the outer tube (the first) works as a casing.

GEOBOR S - the ultimate sampling system;Continuous Wire Line large diameter (146/102 mm) core drilling with triple tube core barrel, takes 1,5 m length samples.

The GEOBOR sampling system was developed for complex geological, geotechnical, hydrogeological investigations, according to the core barrel and the core bit type consist of VII methods in accordance with soil properties and the purpose of investigation.

Method I in medium to hard formations;Most suitable for domestic soil conditions, all types of core bits can be used depending on the formation.

Method II in soft formation;For coring in soft to very soft formations, only TC-set bits are used and the bit consist of two parts (pilot and reamer).

Method III in very soft formations;For coring in very soft or loose formations. Only TC-set bits are used, the bit is in two parts as in method II but the core lifter is extended to run 25 mm in front of the bit.

Method IV in soft varying formations;For coring in very soft, loose formations with varying layers. The springloaded inner tube assembly is extended to run in front of the bit, but is retractable for optimized adaptation to the hardness of the ground.

Method V "Shelby" sampling;A Shelby type sampling tube replaces the standard inner tube and a soil sample can be obtained in front of the bit.

Method VI full hole drilling;A full hole drilling assembly replaces the standard inner tube assembly for non coring purposes.

Main page; Company review; Geotechnical drilling rigs; Field instuments, tests on the site; Planning operations; Selected project list; Press matter;

GEOVIL LTD. Š; October 2005