The biophysical environment is defined as the physical environment (water, soil etc) as well as the biological activity within it (plants, animals etc.). Services offered include baseline assessments, specialist studies, impact assessments; contamination assessments, as well as the compiling of management measures, either as part of standard authorisation requirements or as independent specialist studies. The following services are offered:
Fauna and Flora Assessments
These assessments determine the overall terrestrial ecology of an area and include the flora community and the associated fauna such as invertebrates, avifauna, mammals, reptiles and amphibians. The baseline ecological conditions are determined and potential negative impacts of development on the ecology are projected and mitigation measures are developed. Assessments are also made as to whether any rare or endangered species or habitat could be affected by a proposed project. The implementation of management measures (e.g. relocation of red data species) is also undertaken.
In order to determine the ecological integrity of the aquatic environment, individual biophysical components of rivers, streams and dams are assessed. These components are studied within rivers and streams through aquatic biomonitoring, monitoring of invertebrates, river integrity (health) assessments and toxicity testing. Accepted standard methodologies (e.g. SASS5 in South Africa) are used where required. Aquatic assessments of dams, pans and other such systems are undertaken and utilise the fish population dynamics as an indicator, biomarker analysis, fish health assessments and telemetry to collect relevant data.
Wetland assessments are conducted to determine the extent of the wetland area, to document its current ecological state as well as the ecological services the wetland provides. Wetland areas are delineated and buffer zones or offset areas are assigned depending on the ecological status, importance and sensitivity of the wetland. Management programmes to upgrade degraded areas are devised.
Biodiversity assessments are conducted to determine the health and functioning of the environment through the study of terrestrial and aquatic ecosystems. The findings from the assessments are then used to develop Biodiversity Action Plans which provide management strategies for the biophysical environment. Biodiversity monitoring is also undertaken. The Biodiversity Action Plans are management plans integrated with GIS into an interactive management tool.
Soil Surveys, Land Capability and Land Use
Prior to land disturbance the agricultural potential, depth and extent of the soil resources are determined to provide soil management advice during development and rehabilitation of a site. Digby Wells is pioneering Predictive Soil Mapping techniques in conjunction with the University of the Free State, which enable significant cost savings when compared to traditional grid surveys for large areas.
The soil mapping forms the basis for assessing the land capability. Current land use is also assessed in conjunction with the social studies and GIS in a project.
The rehabilitation of areas disturbed by mining is required to ensure the sustainability and an acceptable post closure land capability and land use. The rehabilitation planning should start prior to breaking ground as this ensures optimal movement of material for both opencast and underground operations.
The design of the various mine waste deposits that will remain after closure also needs to be done with final rehabilitation in mind.
Air Quality Assessments
Fallout dust is monitored using dust bucket samplers and then analysed to establish baseline conditions before the development of a site. The results are interpreted and management plans are developed for a project. On-going monitoring is also offered by Digby Wells during construction, operation and decommissioning phases.
The impact prediction is conducted at the hand of air quality dispersion models constructed for each site taking into account the relevant topography, climate as well as sources and receptors.
Surface hydrology is assessed in terms of quality and quantity of the current hydrological environment, the likely impacts and the resultant management plans. This includes water quality assessments, flood hydrology and flood lines, storm water management plans.
Specialist skills in relation to the selection of mine water treatment options during the operational and post closure phase is delivered.
Comprehensive monitoring services as well as regular data interpretation and reporting on data collected by the company, or the client, are offered.
The ground water team at Digby Wells has experience in water-provisioning studies, aquifer characterisation, geophysical investigations, mine dewatering, ground water pollution studies and numerical modelling.
The Hydrogeological services offered include groundwater baseline assessments, water provisioning, mine water ingress, quality and quantity monitoring and full numerical modelling of quantity and quality impacts. Field programmes are designed and implemented.
Staff are also seconded to clients for larger projects at favourable rates.
The company has its own geophysical instrumentation and team for Electromagnetic and Magnetic techniques and access to reliable suppliers for Resistivity, Gravity and Airborne geophysical techniques.
Geochemical AssessmentsGeochemical investigations are integral to understanding the risks posed to the environment from mining operations and their associated waste facilities. Digby Wells undertakes a range of investigations varying from initial Acid Base Accounting, mineralogical analyses to full geochemical modelling through its own staff or associates.