Acid Mine drAinAge ( AMd ) MAnAgeMent 285 Acid Mine drAinAge ( AMd ) MAnAgeMent
AMd is recognized as one of the most serious environmental problem in the mining industry. the problem of acid mine drainage (AMd) has been present since mining activity began thousands of years ago. Mining activity has disrupted the hydrology of mining areas so badly that it is extremely difficult to predict where water would eventually re-emerge. its causes, treatment have become the focus of number of researchers. this paper describes Acid Mine drainage (AMd) generation and its associated pollution. Jr. of Industrial Pollution Control 23 (2)(2007) pp 285-297
Modification of acid mine drainage in a freshwater wetland
Tub 'Run Bog, a freshwater wetland in the Appalachian Mountains of West Virginia, is bounded along its eastern edge by an abandoned surface mine. Through the weathering of the exposed pyrite‐ bearing overburden rocks, acid mine drainage is formed and flows into the wetland irk overland and subsurface flow. lie present three lines of evidence to suggest that Tub Run Bog is effectively ameliorating the quality of the acid mine drainage as it percolates through the wetland. First, interstitial water from‐tube lysimeters across‐70 m long transects from the surface mine edge into the wetland shows a general decline in the, concentrations of hydrogen and sulfate ions with increasing distance from the surface mine. Second, hydrogen sulfide determinations in interstitial water indicate that biological sulfate reduction is occurring at Tub Run Bog. Third, the chemistry of stream water draining; Tub Run Bog is similar to the chemistry of stream water draining other nearby watersheds and shows little influence of acid mine drainage. We suggest that biological sulfate reduction and the subsequent precipitation of insoluble iron sulfides and/or the evolution of reduced sulfur gases from the wetland soil may be the important processes in modifying the acid mine drainage.
Numerical tools applied to power reactor noise analysis
In order to be able to calculate the space- and frequency-dependent neutron noise in real inhomogeneous systems in two-group theory, a code was developed for the calculation of the Green's function (dynamic transfer function) of such systems. This paper reports on the development as well as the test and application of the numerical tools employed. The code that was developed yields the space-dependence of the fluctuations of the neutron flux induced by fluctuating properties of the medium in the two-group diffusion approximation and in a two-dimensional representation of heterogeneous systems, for both critical systems and non-critical systems with an external source. Some applications of these tools to power reactor noise analysis are then described, including the unfolding of the parameters of the noise source from the induced neutron noise, measured at a few discrete locations throughout the core. Other concrete applications concern the study of the space-dependence of the Decay Ratio in Boiling Water Reactors, the noise-based estimation of the Moderator Temperature Coefficient of reactivity in Pressurized Water Reactors, the modeling of the beam- and shell-mode core-barrel vibrations in Pressurized Water Reactors, and the investigation of the validity of the point-kinetic approximation in subcritical systems driven by an external source. In most of these applications, calculations performed using the code are compared with at-power plant measurements. Power reactor noise analysis applications of the above type, i.e. core monitoring without disturbing plant operation, is of particular interest in the framework of the extensive program of power uprates worldwide.