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'"t <br />E~~A <br />Coal Company <br />Seneca Coal Compa <br />April 26, 2007 <br />Mr. Daniel Mathews <br />Division of Reclamation, Mining and Safety <br />101 South 3~d, Suite 301 <br />Grand Junction, CO 81501 <br />RE: Seneca II-W Mine (PemutNo. G82-057) <br />Technical Revision No. 58 (TR-58) <br />Hydrology Monitoring Program Changes <br />RECEIVED <br />MAY 0 8 2001 <br />Division of Reclamation, <br />Mining and Safety <br />Dear Mr. Mathews: <br />Enclosed are two (2) copies of an application for a technical revision to the Seneca II-W Mine Permit <br />(G82-057). A third copy has been sent to the Division's Denver Clffice also addressed to you. TR-58 <br />requests changes to the hydrology monitoring program as described below <br />Due to the closing of the Seneca IIW Mine, SCC has requested a reduction in monitoring frequencies <br />of streams, springs and wells. These reduced monitoring frequencies will be continued until a year or <br />two before final bond release, at which time monitoring frequencies will be increased Table 1, Laurent <br />Hydrologic Monitoring Program (pages 15-3a-4 to 6), has been revised to reflect these changes. The <br />details of the changes are provided below. <br />For ground water monitoring wells, the frequency of water level measurements has been changed from <br />tri-annual to semi-annual (May/June and September/October). Water qualitysampling of alluvial well <br />GW-S2W-21A (Sage Creel{) will be changed from triannual to semi-annual. Water quaGtysampling of <br />all other alluvial wells mill remain unchanged (semi-annual, or in some cases, triannual). Water quality <br />sampling of bedrock v,~:lls will change from semi-annual to annual (May/June), since the bedrock wells <br />are subject to less change in water qualitythan the alluvium. <br />Water quaGtysampling will be discontinued at wells GW-S2W-160V and 16W. This set of wells exists <br />between the A/B and C%D pit areas in the north area. Well 160V ofren does not have enough water <br />in it to sample. Well 16W ofren does not have enough water in it to sample, or is dry. Better monitor <br />wells exists below the A/B pit (# 17 series) and C/D pit (# 14 series). <br />For stream sites, monitoring at SW-S2W-SG5 (DryCreep, SW-S2W-FGl (lower Hubbeaon Gulch) <br />and SW-S2W-FG4 (Sage Creek) have been changed from monthlyto tri-annual (spring runoff, post- <br />runoff and baseflow). Fur springs and spoil springs, monitoring has been changed from semi-annual to <br />annual (May to July}. <br />All monitoring at Spring 5-23 will be discontinued. 'This spring is located in a stream channel in an <br />undisturbed area above Pond 006. It has an average flow of 1.15 gpm and a mucirntun flow of 10.3 <br />gpm. Electrical conductivity and TDS values at this spring exhibit a stable trend. <br />All monitoring at Spring 5-48 will be dscontinued. This spring is located in an undisturbed area above <br />Pond 009. It has an average flow of 2.66 gpm and a maxurrurrt flow of 6 gpm Electrical conductivity <br />values at this spring exhibit a stable trend. <br />Seneca Coal Company a P,O. Box 670 a Hayden, Colorado 81639 <br />Telephone (970) 276-3707 a FAX (970) 276-3014 <br />