Dolomite stability investigations are required for all land classified as dolomitic land. Dolomitic land is considered land underlain by dolomite or limestone residuum or bedrock typically at depths of no more than:
- 60 m in areas where no de-watering has taken place and the local authority has jurisdiction, is monitoring and has control over the groundwater levels in the areas under consideration; or
- 100 m in areas where de-watering has taken place or where the local authority has no jurisdiction or control over groundwater levels.
The Feasibility-Level investigation (otherwise known as Phase I dolomite stability investigation) shall be carried out by a competent person for all developments on dolomitic land to form the basis of development planning and broadly delineate the site into inherent hazard zones which are guiding the allowable land usage.
The report of a Feasibility-Level dolomite stability investigation shall cover at least the following as per SANS1936-2:2012 document:
- Description of the site and define its extent and boundaries
- Describe the investigation carried out and present the results thereof in detail
- Establish the geotechnical model for the site
- Establish the nature, fluctuations and compartmentalisation of groundwater, and original groundwater levels from geohydrological data
- Assesses the effect of changes to the groundwater level
- Determine the inherent hazard class of the site or of the various portions thereof
- Determines the dolomite area designation and appropriateness of proposed land usage in accordance with the requirements of SANS1936-1:2012
- Provides the information needed for identification of the precautionary measures required in accordance with SANS 1936-3:2012
- Provides the information needed for risk management strategies in accordance with SANS 1936-4:2012
- Identify any outstanding information to be determined or confirmatory investigation to be undertaken during the Design-Level investigation, particularly in respect of verifying or refining the inherent hazard class of the site or parts thereof
The investigation methodology, evaluation and reporting should be in accordance with SANS1936:2012 and the latest NHBRC manual.