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(2) There is no thermodynamic support to the contention that Na would not be removed <br />from solution. <br />The second refutation is a simple thermodynamic observation. On page 5 of the report, several <br />possible reactions involving Na' are discussed as potential mechanisms for reducing Na-content <br />of water. These ion exchange reactions aze <br />2NaA(SiZ06•HZO+CaZ =Ca(A(SiZ06)Z•HZO+2Na' <br />2NaAlSiZ06•HZO+MgZ =Mg(AlSiZ06)•HZO+2Na <br />Mgt +Na-Clay=2Na= +Mg-Clay <br />CaZ +Na -clay =2Na ' +Ca -clay <br />The statement is made that the Edwazds Portal spring water could not be "in-mine fault water" <br />because no plausible mechanism exists for reducing the Na content of water between the in-mine <br />faults and the Edwazds Portal spring because the loss in Na would require reverse ion exchange. <br />That ignores the equilibrium constant of the reaction, mathematically described by the Gibbs <br />Free Energy G in the following equation: <br />OG~s•=-RTInKa <br />where the (G~ is a function of temperature and the equilibrium constant K, of the reaction. <br />Using the 4th mineral reaction listed above, in which Na is exchanged for Ca in a clay, <br />CaZ +Na-clay=2Na'+Ca-clay <br />the equilibrium constant is the activity of the reaction products divided by that of the reactants. <br />Symbolically, <br />KQ =(aNa)~(aMgcla~l (aMg)(aNarluy) <br />The activity (a) is essentially the concentration of each of those reaction constituents (Na, Ca, <br />Na-clay and Ca-clay). The K, term is a constant for the temperature, so the proportions of <br />each participant in the reaction adjust to maintain equilibrium concentrations at the temperature <br />at which the reaction is occurring. That is, if the Na-concentration of the system in which the <br />reaction is going on is very high, the reaction is effectively "driven" to the lefr, taking Na from <br />solution and replacing Ca on the clay, thus removing Na ions from the water in place of calcium. <br />