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iii iiiiiiiiiiiiiiii~ ~.:: ~ ; .:: ~ _ :. , :_• : ~:~' :.::,. ~ : ,:: . <br />..; <br />.. •.~- ,. <br />January,28, 1997.,.' - ~GCEI~.IED <br />14Ir. KenfGorham ~ ~ dAN. 2.9 1997 <br />Colorado Division of.Minerals and Geology <br />1313 Sherman, Room 215 <br />Denver, C0.80203 _ .: ;., .~ ,,.~aerai§ & Geolo9Y <br />Subject: Technical Revision 44,. Modification of the Hydrologic Monitoring Plan, Basin <br />Resources Inc., Golden Eagle'Mine, G-81-013 <br />Dear Mr. Gorham:. . <br />Basin Resources is proposing a modification of the hydrologic monitoring plan (HMP) for. the <br />bond.liabiliry period. This modified plan focuses on the probable hydrologic consequences of a <br />reclaimed underground mine, and minimum statutory requirements at the site. 'The revised HMP <br />reduces: the number of sites, decreases the frequency of monitoring and modifies the parameter <br />list as descrilied below. <br />The operational.HMP had ten surface water monitoring sites, six ponds, four alluvial wells arid <br />eight bedrock wells. The bond•liability period HMP has limited the surface sites to locations <br />upstream and downstream of disturbance on Ciruela Canyon and on the Purgatoire. The original <br />surface monitoring.plan included sites with three objectives which are not longer.applicable to the - <br />.mine: sites"which had bcen established to `provide baseline data for future miniag; sites which <br />were established to provide information on affected areas; or sites which provided data on mine <br />water discharge impacts. The bond.lialiility period HMP has decreased the number.of ponds to' <br />reflect the reclamation that has occurred. "The operational HMP had four alluvial wells and the <br />bond liability plan has three. "PAW-7 was eliminated as it was located halfway between the upper <br />and lower end of disturbance ar the -site; and as such provided inconsequential long=term <br />information. Basin is proposing a reduction in bedrock wells to reflect some physical limitations <br />associated with sampling the wells, and.to acknowledge the addition of some valuable information <br />from the new underground workings sites (the GEM series). <br />The operational monitoring plan had a large number of sites with monttily field parameters to <br />better characterize the impacts.associated with mine water discharges at the mine for the surface <br />and alluvial sites and to provide baseline data for the North Pod permit revision at the bedrock <br />sites. Field parameters have been reduced to a quarterly frequency for the surface and alluvial <br />sites, and semiannually for the confined bedrock sites. <br />The annual parameter list has been modified to eliminate nonessential major cations and anions <br />(chloride and potassium) and to provide supplemental information on the various forms of iron <br />and manganese. Fluoride was dropped for the ground water samples, as there has rarely been an <br />exceedance. Basin is proposing the addition of a short list to be monitored on a quarterly basis <br />at the surface, alluvial, and flooded working sites which would provide information on total <br />dissolved solids, iron, and manganese. The short list would also provide total suspended solids <br />5990 Greenwood Plaza Blvd. Suite 250 Englewood, CO SOlll <br />ranai>;sn_n4an .Farranaiv~i_gv4R <br />