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• The mine waste material shall be put in place in lifts that optimally should be <br />between 12-18 inches and in no case shall exceed 24 inches. The density of <br />each lift should meet state regulations, which require that waste material be <br />compacted to at least 90% of the maximum dry density. <br />A Proctor Tesl was run on soil samples from the existing waste pile to <br />determine the maximum dry density and the optimum moisture content of that <br />material. The tests conformed to the required AASHTO T99-74 standard <br />procedure. The maximum dry density was 91.0 pcf and the optimum moisture <br />content was12%. <br />Ongoing Density Measurements: <br />As construction of the pile progresses, periodic density measurements of the <br />compacted fill material shall be performed. The following guidelines should be <br />used. <br />1. The density of all waste material placed on the pile shall be at least 90% of <br /> the maximum dry density. <br />2. A Standard Proctor Test (AASHTO T99-74) shall be performed near the <br /> beginning of construction to establish baseline parameters. Subsequent test <br /> can be performed using a nuclear density gage. <br />3. A random test shall be performed during each of the first five years of <br /> construction and at least every other year after that. <br />4. If at any point during the construction of the waste pile, the consistency of the <br /> waste material changes, another Standard Proctor Test shall be performed to <br /> verify the validity of the current baseline parameters. <br />5. If the results of a random density test fail to meet the required 90% <br /> compaction one or more follow up tests shall be performed until the site <br /> engineer is confident that compaction standards are being met. <br />6. The site engineer shall determine the number of measurements and location <br /> of tests. Both of these will vary as the waste pile increases in size. <br />Topsoil and Fill Cover Material: <br />Final reclamation of the waste pile requires that there be 3.5 feet of cover and <br />6 inches of topsoil on top of the waste pile. The fill material may consist of <br />naturally occurring soil and rock removed from the site and stockpiled in <br />preparation of placement of waste fill. All vegetative material should be removed <br />prior to stockpiling the cover material. Material appropriate for topsoil should be <br />kept in a separate pile. Cover material stockpiles should be located near the five, <br />ten and fifteen year estimated elevations of the waste pile (or at other logical <br />intervals which will reduce the transport cost during fill placement). <br />The unit weight and composition (percent topsoil, rock, other soil etc.) of <br />• cover material should be periodically estimated during the clearing process. This <br />January 1998 <br />