Abstract
Soil hydrological and mechanical processes and their effect on the environmental performance of rebuilt landforms
Rebuilding of landforms for mine closure has the intention to create an environment which provides long term safety, stability, sustainable performance and prevents pollution. A range of criteria are required to be met to satisfy this main objective of landform design and a rebuilt landform will have to suffice certain desired (ecosystem) functions. In a natural environment, landforms are a product of geology, climate, time and biological activity. It can be assumed natural landforms are in a kind of steady-state equilibrium with environmental factors in which hydrological and mechanical processes are the dominant drivers for change. Rebuilt landforms are not necessarily in an equilibrium state with their environment and are exposed to processes which may change their initial functional properties.
Water is one of the main factors influencing the performance of landforms as are mechanical and chemical properties of materials and substrates used to construct a landform. Substrates may increase their mechanical stability by age hardening, but the release of confining stresses from rock after mining waste rock and exposure to the elements may have the opposite effect. The risk of surface erosion may decrease with structure formation and increase infiltration of a surface substrate over time, but it may also decrease with transport of salts towards the surface and higher dispersivity of the topsoil. The presentation will explain such hydrological and mechanical processes leading to change in properties, present examples of consequences and provide suggestions to avoid unwanted outcomes in the environmental performance of rebuilt landforms.
Soil hydrological and mechanical processes and their effect on the environmental performance of rebuilt landforms
Rebuilding of landforms for mine closure has the intention to create an environment which provides long term safety, stability, sustainable performance and prevents pollution. A range of criteria are required to be met to satisfy this main objective of landform design and a rebuilt landform will have to suffice certain desired (ecosystem) functions. In a natural environment, landforms are a product of geology, climate, time and biological activity. It can be assumed natural landforms are in a kind of steady-state equilibrium with environmental factors in which hydrological and mechanical processes are the dominant drivers for change. Rebuilt landforms are not necessarily in an equilibrium state with their environment and are exposed to processes which may change their initial functional properties.
Water is one of the main factors influencing the performance of landforms as are mechanical and chemical properties of materials and substrates used to construct a landform. Substrates may increase their mechanical stability by age hardening, but the release of confining stresses from rock after mining waste rock and exposure to the elements may have the opposite effect. The risk of surface erosion may decrease with structure formation and increase infiltration of a surface substrate over time, but it may also decrease with transport of salts towards the surface and higher dispersivity of the topsoil. The presentation will explain such hydrological and mechanical processes leading to change in properties, present examples of consequences and provide suggestions to avoid unwanted outcomes in the environmental performance of rebuilt landforms.
Presentation
Soil hydrological and mechanical processes and their effect on the environmental performance of rebuilt landforms
Presented on 12th April 2018 at the 8th Annual Best Practice Ecological Rehabilitation of Mined Lands Conference (2018)
tf_baumgartl_t_soil_hydrological_and_mechanical_processes.pdf |