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<br />III IIIIIIIII'llllll <br />Mathews, Dan <br />From: Mathews, Dan <br />Sent: Wednesday, November 14, 2001 10:30 AM <br />To: Burnell, Jim <br />Cc: Brown, Sandy; Berry, David <br />Subject: Follow-up to Powderhorn AHR issue <br />Hey Jim. Recall that in your review memo of 8/6/01 for the Roadside 2000 AHR, you made the following observation: <br />"One additional note should be made. It was noted that the hydrochemistry of the outfalls reported in the AHR are based <br />on 'total' values, not dissolved values. Hence, even a small amount of sediment within the sample makes interpretation of <br />the water chemistry impossible, since the quoted analyses include the chemistry of the sediment carried in the water. This <br />hadn't been noted last year but there was a large change in the apparent chemistry of the water from Discharge 01 this <br />year, but this is likely due to the presence of sediment in the water and not the chemistry of the water itself." <br />That piqued my curiosity for a couple reasons. There were some pretty dramatic differences in water chemistry (for <br />example SAR increasing from 0.57 in August 1999 to 21.1 in August 2000), but TSS was reported as "less than 5 mg/I" <br />both years, and there was a change in the source of water discharged via Site 001, which occurred between the 1999 and <br />2000 samplings. As noted on page 2 of the report, ouffall 001 was historically used to discharge overFlow from the <br />minewater system which supplied water to the wash plant. However, the wash plant shut down in late 1999, and in the <br />spring of 2000, a discharge pipe was installed from the No. 2 South Mains (at the far upper end of the mine workings) to <br />ouffall 001, to supplement the main minewater discharge system (ouffall 002) by routing 75gpm out through 001. I thought <br />there was a good possibility that there was a real difference in water quality, and that the dramatic differences in parameter <br />values was not solely an artifact of "total" rather than "dissolved" values. Values reported for August 2001 were in general <br />pretty consistent with the August 2000 values. <br />So I requested the operator to obtain another discharge 001 sample and have it analyzed for both "total" and "dissolved" <br />values, for selected parameters. I received the results of the requested sample, obtained 10/17/01 yesterday, and I will fax <br />the analyses to you, along with a rough chart I put together comparing selected values for August 1999, August 2000, <br />August 2001, and October 2001. The differences between total and dissolved values are very small in comparison to the <br />differences between values prior to August 2000 and after August 2000. I think the data reflect a real difference in water <br />quality resulting from the changed source of the discharge water. I understand your explanation for why reporting of <br />dissolved constituents might be preferable to total constituents for minewater discharge, but this seems to be at odds with <br />rewmmendations in our Water Quality and Overburden Guidelines and Material Damage Guidelines. <br />So I have a few questions: <br />What do you make of the data now? <br />2. Should I have Powderhorn revise their permit to specify reporting of dissolved constituents for minewater <br />discharge? <br />3. Has DMG policy changed in this regard, such that the guidelines are now outdated in regard to this issue? <br />Thanks Jim. I'll fax the info right away. Now back to the files... <br />