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TECHNICAL MEMORANDUM <br />AmerAlia, Inc. <br />October 19, 1999 <br />Page 6 <br />Waters in the dissolution zone are of a sodium bicarbonate type. In this water-bearing zone the pH is <br />alkaline, with a median value of 9.0. Two wells completed in the dissolution zone show a large variation <br />in concentrations. Concentrations of TDS in well DS-2 (47,000 mg/I) are approximately one order of <br />magnitude higher than concentrations in well IRI-7 (4,500 mgll). Similar order of magnitude differences <br />between both wells exist for boron, chloride, fluoride, magnesium, potassium, sodium, and sulfate. <br />Agricultural standards are exceeded by third quartile concentrations of boron, fluoride, TDS, and pH. <br />Conductivity and TDS in the Dissolution Surface zone show a defined increase since begin of monitoring <br />in both wells. However, pH, seems fairly constant around 9.0. Graphs for conductivity, pH, and TDS <br />measurements and graphs and tables For monthly averages are contained in Appendix C. <br />' 2.4 Water Levels <br /> <br />i , <br />Water levels have been measured in Wells TH 75-7A and 7B since 1975 (Appendix D). The water level <br />in TH 75-7B (lower aquifer) indicates a slow rise by about 20 feet since 1975, whereas water levels in <br />TH 75-7A seem fairly constant since 1975. The data does not show any seasonal variations in water <br />level. Water levels in Well GS-S24 ranged from 5.1 to 15 feet below surface in the period from 1975 to <br />1980. The water level data are presented in Appendix C. Ground water levels from other nearby <br />projects were not used in this analysis because they are not available or the data have been impacted <br />from mining operations and do not reflect baseline data at the Project site. <br />3.0 SPRINGS AND SEEPS <br />Only one spring was historically monitored in the general Project area. This spring is located in Corral <br />Gulch drainage, upstream from the confluence with Yellow Creek, and is designated as Spring #14 <br />(S000109830CAAD) in the C-a Tract Monitoring Plan. Limited monitoring data for this spring are <br />available from September 1975 to September ]984 (Table 2). Discharge from Spring #14 varies from <br />2 to 193 gpm, with particularly high flows in 1984. The water of Spring #14 is of a mixed magnesium <br />sodium sulfate bicarbonate type. The pH is consistently near neutral, temperature ranges frotn 3 to 22°C, <br />and electric conductivity from 1,600 to 3,000 µS/cm (Table 2). Water type Corral Gulch is presented in <br />a Piper Diagram in Appendix B. The spring water exceeds agricultural water quality standards for TDS. <br />During the September 1999 survey, Corral Gulch was flowing at the location of Spring #14 and no spring <br />area was observed. The flow in Corral Gulch at this location was approximately 0.1 cfs. <br />2ndFinalTechnical Memo doc 10/19/99 TRC HYDRO-GEO CONSULTANTS <br />