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Permit M77-424 Amendment 1 <br />EXHIBIT D <br />MINING PLAN <br />A) Mining Methods. <br />Exhibit D <br />Page 1 of 6 <br />A description of mining methods to be employed at the mine are discussed in Exhibit D <br />of the original mine permit M77-424. This amendment is being submitted to address <br />construction activities associated with the water transmission pipeline and evaporation <br />pond. The construction of these facilities was implemented in 1984. Because records of <br />those activities are limited, this exhibit will present a summary of assumed activities <br />undertaken at the time of the construction of the water transmission pipeline and the <br />evaporation pond. <br />The evaporation pond, also referred to as Pond A, and associated water transmission <br />pipeline were constructed in 1984 as a solution to manage and treat mine drainage from <br />the underground oil shale retorts at Logan Wash Mine. These facilities were constructed <br />after it was determined that previous treatment methods were less cost effective in <br />treating the discharge water from the retorts. <br />The original mining plan as shown in Sheets 2 and 3 of Exhibit D indicate that 3 <br />evaporation ponds were considered for construction with the intention of building the <br />ponds successively, as needed. Pond A, including the initial settling pond, was the only <br />evaporation pond constructed. <br />B) Earthmoving. <br />It is assumed that conventional earthmoving techniques and equipment were used in the <br />construction of the water transmission pipeline and evaporation pond. Excavators, <br />bulldozers, loaders, scrapers, motor graders and dump trucks, are equipment expected to <br />have been used for construction. It is not likely that soil was exported from the site or <br />imported to the site, however, aggregate fill was imported to construct the leak <br />detection/capture system. <br />C) Water Diversions and Impoundments. <br />The facilities described in this amendment as additions to the mine permit are considered <br />water diversion and impoundment structures. The original mine permit M77-424 <br />describes the design of other water diversion and impoundment structures associated with <br />the mine site (see Exhibit D in rho mine permit). The following information provides a <br />review of past construction activities relevant to the retort pipeline and evaporation pond. <br />The sealed L-1 Portal, the main portal at Logan Wash mine, dischazges two water types, <br />retort water and "mine water". These waters are captured in the mine and discharged at <br />locations on the surface. Mine water is water that enters the mine through natural <br />