Geotechnics

Mining, Tunnel construction, Inflow sealing, Permeability Reduction, Shaft Sealing

We offer development, testing and modification of injection material for sealing of porous salt and rock areas. Such systems are used in order to fight water and brine inflows into mines, shafts and tunnels. In particular, we hold widespread experiences regarding the adjustment of grouts for application in brines of various compositions.

Examples for grouting materials are:

Supersaturated solutions, which are characterized by directed mineral (Gypsum, CaCO₃, Ca(OH)₂ etc.) precipitation (provoked mineral formation)
Waterglass/sodium silicate
Cement, cement/fly ash/bentonite-mixtures
Gel forming systems (both biopolymers and synthetic polymers)
Polymers like acrylates, urethanes and epoxides
Latex or bitumen emulsions

We are the partner for all stages of the process:

Pre-study

We analyze both available data and samples in order to develop recommendations. We give advice concerning the planning of further pre-tests.

Geological and geotechnical investigations of drill core samples, bulk material etc.
Characterization and selection of drill cores (rock type, color, stratification)
Analysis of maps and further data
Water content, water retention and water permeability
XRD measurements, mineralogical characterization, mechanical properties, particle size distribution
Market analysis concerning existing injection materials including recommendations for the current project

Laboratory investigation

From our experience it is always required to adjust the recipes to the conditions on site, even if the used grout material is well established. Frequently there is no suitable ready-to-use system available. In this case, our laboratory studies can help.

Viscosity, pumpability and injectability
Water content
Mechanical properties and density
Characterization of swelling, shrinkage, and bleeding behavior
Lab testing, adjustment and optimization of injection material
Evaluation of alternative additives (avoidance of toxic and environmentally harmful substances)
Influence of brine composition, in particular for systems developed for aqueous applications
Injection tests using flow cells and columns as well as injection packers
Acceleration or delay of setting time
Resistance to salt solutions, aggressive waters, temperature and pH alterations as well as special environments
Evaluation of injection method and strategy as well as selection of injection material

On-site support

We provide support for the realization of field tests, ideally with personal presence of one of our experts. This enables fast reaction and problem-solving, just in case that there are deviations from the expected behavior despite the comprehensive pre-studies.

Selection and compilation of suitable equipment
Advice and training of staff member regarding the handling of the injection materials
On-site field tests
(Lugeon test, Injection tests in IBC containers, …)
Assumption or support of quality assurance

Documentation and reporting

We offer preparation of final documentation and reports including external reviews. The latter is of course not limited to investigations, which were realized under our supervision.