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CHAPTERFOUR <br />Environmental Consequences <br />and precipitate nahcolite thus sealing potential migration pathways a short distance from the <br />mine cavity. ~ ~ '~ <br />'~ ,~.. e. <br />Leakage from the evaporation ponds at the Piceance Site could also result in degradation of the ~~, ~ y ' <br />quality of water, particulazly in alluvial aquifers if present neaz the ponds. Although the ponds d~~•~ ?`, ~''} <br />will be lined, a liner failure could result in the migration ofelevated-TT)S water from the surface ws%•' <br />to alluvial aquifers. Quantification of this type of impact is not possible because flow rates and Q' ty~. h <br />fluid concentrations cannot be readily predicted, but the planned leak detection monitoring and tr ~ e-~a, _ <br />recovery/pump-back system would help minimize releases to groundwater. tnb~3 t~` 6~ fi't` <br />Other direct impacts aze related to the degradation of water quality in the Lower Aquifer ~- l~^ ~'S V~~ w: ' '' <br />(Parachute Creek Member) from potential rel es of production fluids. The Lower Aquifer .r -V•' ' <br />TT)S values that range from 600 mg/1 to 4 , 00 mg/1; therefore, the Lower Aquifer groundwater ^`"'' <br />does have TT)S concentrations within dnnking water standazds in azeas of the Piceance Basin. <br />Data obtained from the White River Nahcolite (1997) operation (located approximately 2 miles <br />west of the proposed mine site) indicate that the water quality in the upper part of the Lower pp <br />Aquifer is 1,080 mg/1 TDS. This indicates that the Lower Aquifer may have water quality that is Jt ~ <br />usable for stock watering or crop irrigation. However, data collected by American Soda in the ~., ~ tom'. <br />vicinity of the experimental mine site indicates that TT)S values aze in excess of 60,000 mg/l and ~x-`t~•~'y <br />levels of fluoride and several other constiruents aze above Colorado drinking water and irrigation ~~ /~ ~ <br />t <br />standazds. v N~ i+~r <br />k <br />Releases of production fluids via casing leaks or mining cavity fluid excursions could elevate th o„e ~ r •' - _ <br />5 concentrations in either of these aquifers and be detrimental to the ttsefiriness of either aquifer.~A ~-~y~' <br />release of the production fluid wotild not change the water type of either aquife since the fluid ~ -''~ <br />~h has a similazcation-anion balance to the groundwater. These impacts would b the s2..t~ rl'M. 1,r~` <br />~- <br />both action alternatives. ~~ u~1b a a „sr_r <br />'` The potential for impacts to Piceance Creek exists from the possible intro uc ton o groundwater -/~ `~~.` ~' <br />,r ` with elevated TT)S d' chazging into the creek. Currently, the creek interacts with the aquifers r~ '` ~ a <br />r` cya <br />y that underlie i ~by wing r gaining groundwater as it flows past the aquifers. Should the LFr"~,Sk. ,,. <br />r dt eren ead between the tree c an the aquifers create a positive flow into the creek, water ~ d ; ~ryr <br />that may have been impacted by operations would enter the creek. This could result in ~'~ „>•~ <br />groundwater with elevated TT)S concentrations entering the creek. ._ ~'~°[ <br />Potenti or m rect impacts to the groundwater quantity and cjuality may result from ' <br />subsidence. Subsidence in the Project Area could potentially fracttue rocks both vertically and <br />horizontally and result in increased hydraulic conductivity. Of significance is the potential <br />fiacturing of the semi-confining Mahogany Zone, which separates the Upper and Lower <br />Aquifers. The increased hydraulic conductivity cotild potentially allow for the migration of <br />higher TT)S groundwater from the Lower to the Upper Aquifer or for migration of lower TDS ti <br />groundwater from the Upper Aquifer to the Lower Aquifer. The increased hydraulic ,4 ~ t'~ <br />conductivity would result in an increase in the rate of recovery for groundwater pumped from ~ ~ <br />wells in the area. <br />Groundwater 4-15 <br />