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.
17 &mgr;m pixel 640 x 480 microbolometer FPA development at BAE Systems
BAE Systems has developed an advanced 640 x 480 focal plane array (FPA) with a 17 &mgr;m pixel pitch. Sensitivity of ≤ 50 mK was demonstrated and the FPAs were used in imaging demonstrations. Successful scaling of BAE Systems' patented single contact per pixel, single-level microbolometer process to 17 &mgr;m pitch provides a path toward next generation microbolometer imaging systems.