Open Cut » Environment
One of the major challenges to rehabilitating land that has been disturbed by mining is the re-establishment of a self-sustaining vegetative cover. Restoration of acceptable vegetative cover on reclaimed mine lands can be difficult because post-mining soils often have a less developed soil structure and reduced organic matter and plant-available nutrient contents than the original in situ soils.
Microorganisms are increasingly recognized as being important for successful reclamation because of their vital role in nutrient cycling, plant establishment and growth, geochemical transformations, and soil formation. A primary function of many soil microorganisms during soil restoration is to promote organic matter turnover and nutrient cycling through diverse metabolic functioning.
This study examines four mine sites undergoing rehabilitation using standardized sample treatments and isolation media to distinguish the numbers of bacteria, actinomycetes and fungi (as colony forming units) in soils. Carbon-utilization profiles are used to provide a metabolic profile or fingerprint of the soil bacterial and fungal communities in the same soils. Two sites at Centennial Coal Company's Charbon Colliery, one site at the Xstrata Coal Bulga Coal Mine, and one site at the Xstrata Coal Ravensworth Operations Narama Mine are examined. The microbial population numbers and community functionality at each of these mine sites is related to a reference site which was the original site vegetation (Charbon), a site where revegetation to native status had been successfully undertaken in the past (Bulga), or a site where pasture had been established (Ravensworth).
In the United States there have been positive revegetation results, reduced soil erosion and accelerated pedogenesis on abandoned logging trails through the addition of myco-remediated organic waste. Bioremediation trials undertaken in this project explore the opportunity for the use of in situ fermentation of organic wastes by fungi for soil creation and the stabilization of plant communities on degraded soils. Although there is evidence that the myco-remediation treatment of the rehabilitation sites affected non-filamentous bacterial and fungal numbers and types of organisms in the underlying soil it did not result in bacterial and fungal community structures which were similar to those of the reference soil communities in the time frame of the study. However, since actinomycete and fungal communities, in particular, are deleteriously affected through soil disturbances other avenues of re-introducing them to soils have been identified in this study which may be more appropriate and timely than the myco-remediation approach used in this project.