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-32- <br />The applicant has not adequately determined the probable hydrologic <br />consequences of the proposed underground mining operations upon springs and <br />seeps in or adjacent to the permit area, or the consequences upon the <br />stream/al]uvial aquifer systems of Apache, Santistevan and Ciruela Canyons. <br />This is due to a deficient inventory of ground water resources. Until the <br />surface and ground water resources are fully inventoried and the probable <br />hydrologic consequences of mining upon these resources is assessed, secondary <br />and retreat mining south of the Purgatoire River and beneath the alluvium of <br />Santistevan Canyon cannot be approved by the Division (See Stipulation Nos. 7, <br />8 and 9 in Section VI, Hydrologic Balance; Ground Water of this findings <br />document). <br />The applicant has provided a discussion of the water quality effects of mine <br />discharge from the Maxwell Mine upon the Purgatoire River stream-alluvial <br />aquifer system. The water discharged from the mine is a sodium-bicarbonate <br />type water with an average pH of 7.9, and an average total dissolved solids <br />level of 1,112 mg/1 (see Exhibit 6, Table 6 of the Maxwell permit <br />application). Under low flow conditions, this discharge would increase the <br />total dissolved solids level in the river by 47 mg/1; under average flow <br />/~ conditions the predicted increase is only 13 mg/1 (Exhibit b, Table 8). <br />/~ {/ The applicant proposes to construct a 6 acre coal refuse pile, West I refuse <br />~v disposal site, at the mouth of Ciruela Canyon. Observations of the disposal <br />v ~ site have found a spring which could come into contact with the pile resulting <br />~~,in a leachate that may degrade water quality. The alluvial ground water <br />quality in.Ciruela Canyon may be impacted by the proposed placement of the <br />disposal pile. <br />The applicant has not provided an analysis of the impacts upon the hydrology <br />that would occur by disposing of the refuse at this site. Also, the <br />significance of al]uvial ground water flows from Cirue]a Canyon to <br />agricultural areas in Picketwire Valley has not been defined. Therefore, an <br />assessment cannot be made and disposal of refuse at the proposed site cannot , <br />be approved. The Division has stipulated, in the Maxwell Mine permit <br />document, that baseline quality and quantity data for alluvial ground water in <br />Ciruela Canyon be gathered as a condition of permit approval. <br />After the cessation of mining operations, the Maxwell Mine water would no <br />longer be discharged. The applicant calculates that 79 years would be <br />required to flood the workings. <br />The recovery of the piezometric surface of the coal aquifer would occur in two <br />stages. The first stage would be a relatively slow increase that would occur <br />as the mine workings are filled by ground water inflows. Once the underground <br />workings have been filled, the piezometric surface would rapidly rise toward <br />its eventual steady state position. A permanent depression in the piezometric <br />surface would exist in the vicinity of the flooded mine workings. The <br />magnitude of the depression would not be large, but it may extend to a <br />distance of 2 to 3 miles from the edge of the mine workings. Because the <br />underground workings lie 400 to 500 feet below the portal areas, the <br />piezometric surface of the mine water would not be expected to rise to a level <br />where it would intersect the ground surf ace, thus discharging through the mine <br />portals or shafts. <br />