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~• <br />Page 2, <br />E. Edwin Hogle <br />~• <br />July 12, 1999 <br />miles north of the American Soda site (Weeks and Welder, 1 E>74; Welder <br />and Saulnier, 1978; and Saulnier, 1978). <br />Despite the early expressed concerns of Rio Blanco County fir complete <br />and unbiased descriptions of the basin hydrology, anomalously large <br />concentrations of dissolved solids and other selected constituents, as <br />compared with basin wide data, consistently reoccurred in permitting <br />documents such as the SOB, the draft ElS distributed by the lJ. S. Bureau <br />of Land Management (BLM), and in documents submitted to other <br />regulatory agencies. Because of the project size, potential impacts, and <br />unusual nature of the permittee's data, it would seem appropriate to <br />involve a disinterested third party for data verification. These unusual data <br />may have resulted from: <br />a. Improperly completed wells at or near the sampling sites. Poor well <br />construction may allow inbore circulation between aquifers <br />(construction diagram for well 20-1 shows that circulation between <br />the A and B groves is probable within the annulus). <br />b. Improper collection of well samples (grab samples, inadequate <br />pumping of well bore volume). <br />c. Collection of samples from wells that contain active inbore <br />dissolution of exposed salt deposits. <br />d. Inadequate or low sensitivity laboratory analysis. <br />e. Contamination of the aquifers from previous activities or from the <br />introduction of different waters to the aquifer systems from ongoing <br />work in the area. <br />3. A review of the basin wide data and using the EPA criteria for USDW as <br />presented in the SOB suggest that most all of the upper aquifer and much <br />of the lower aquifer in the basin might qualify as a USDW (based on water <br />quantity and dissolved solids concentrations less than 10,000 mg/I). <br />4. The last paragraph on page 7 of the SOB is self-contradictory. The <br />Mahogany Zone (MZ) is first described as an "effective barrier" and later <br />as a zone that "may permit some vertical exchange of water". In addition, <br />American Soda has repeatedly assured involved agencies and .the general <br />public that the 150 feet of the overlying saline zone rock above i:he mining <br />zone will contain most, if not all, injection water used for mining. The <br />second sentence in the paragraph, however, infers that injection waters <br />will move into the lower aquifer where the MZ will provide the effective <br />barrier to their upward movement. <br />r <br />