Laserfiche WebLink
• second issue involves upward migration of salts. Clearly it appears that OSM <br />intended a four foot thickness of cover soil as sufficient to protect against the <br />upward migration of salts. While this standard made sense at the time, <br />subsequent findings involving upward migration of sags refute this premise. <br />Specficaly the data of Merrill et. al. (1980) and (1983a) clearly document, <br />that greater thicknesses of respread topsoil promote upward migration of <br />salts rather than retard it. Subsequent data collected by Barth and Martin <br />(1982) and Barth (1984) on sodic mine spoil in the Northern Great Plains and <br />Redente and Cook (1984) on retorted oil shales cleary validate the findings <br />of Merrill. These studies all document that under conditions conducive of <br />upward salt migration substantially more upward salt migration is associated <br />with thicker layers of respread topsoil than for thinner depths. <br />Upon carefully examining the properties of the Southfield Mine refuse <br />materials it becomes clear that the refuse cannot be considered to be toxic <br />or acid forming material and that its limiting potential cannot be documented. <br />Considering all of the suitability criteria R appears that the refuse materials are <br />superior to the native soil materials as a plant growth medium. However, as <br />presented earlier in this report, in order to assure maximum reclamation <br />potential is provided for this site, and to comply with topsoil removal and <br />replacement requirements at Rule 4.06.2 and 4.14.3(1)(8), 16 inches of <br />topsoil should be replaced. <br />• <br />• <br />46 <br />