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III IIIIIIIIIIIII III STATE OF Lv~yty-~~O DIVISION OF MINERALS AND GEOLOGY Dl'pdrlmenl °I Naluml Res°urces I l1 ]Sherman SL, Room 21 S Iry~ Drnv°r, Colorodo 80203 II Phont•'. UOSI 966-356: FA% IS0319.1?-91 Ufi DEPARTMENT OF NATURAL INTERNAL MEMO iiESOURCEs Roy Rnmer TO: David Berry 26 March 1998 c°ver°°` lames 5. Lochhead ~ Execmive DireUOr FROM: Jim Burnell ~"'` Mgnae~ 9. Lo°6 o~v~s~m, olrecsor SUBJ: Mountain oal Water Report Several main points were made in the Mayo report to Mountain Coa] Company and in the Mayo presentation to the CDMG on 21 January 1998 as evidence that water issuing from the spring at the Edwards Portal is not the same water that was Bumped upgradient from the spring by Mountain Coal Company. In the verbal presentation, it appeazed to me that Dr Mayo's main lines of evidence involved the major element chemistry of the waters, particularly the sodium ion content of the two waters, and the carbon isotope composition of Edwazds Portal spring vs sttmped waters. We conclude that these lines of evidence do not show that the spring water is not related to the sump water. Sodium Concentrations The water in the NW panels sump was derived from mine inflow from several faults intersected during mining operations. One of the lines of argument used to show that the Edwazds Portal spring water is not the same water as Bumped water, is the differences in the Na-ion content of the waters from the spring and those from the various faults. The contention is that water emanating from the Edwards Portal contains significantly less Na` than the fault waters and a mechanism to reduce that Na could not have operated to affect the water between the time and location of the two points of analysis. (1) There really isn't much difference in the sodium contents. It is the Division's contention that the Na-content of the Edwards Portal Spring water is not considerably less than that of the fault waters. Individual analyses of "in-mine fault samples" yield values of Na that range from 717 mg/L to 1 175 mg/L. (The range can be expressed in millequivalents as 31.2 to S l .l meq/L.) That compares to a single analysis from the Edwards portal spring of 755 mg/L (32.8 meq/L), a value at the low end, but still within the range represented in the fault waters. The sodium content of portal spring water agrees completely with B East Mains fault water. So the Frst rebuttal of the sodium argument is simply that the sodium content isn't different.