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Mr. ,4frcr'iret Boulry/,b9s. Swa • Drtnsa'.n of A9merab mzf Gm/ogy Sep~iln 29, 1999 Page 9 SCC believes that sufficient documentation has been provided to allow the Division to make a fording that material damage is not an issue in these instances. SCC respectfully suggests that these responses provide sufficient and adequate information for the Division to approve the Yoast Mine PROl so that Seneca can proceed with timely development of the area prior to acrual mining of the Wadge coal seam. 4.05.6 and 4.05.9 Sedimentation Ponds and Impotmdments Comment 36 (Origtnal ConrrertJ SCC u proposing m ccrutruct thrte Harm salnnartaticrr pxeds (Ponds 012, 013, and 014). The designs subrrrittal for rlxse proposal ponds do not rnditde r{x gerota-lnucal analyses mqunul for such fentcsms by Rule 4.05.6(I1JGJ. Plr~tse pnnnde the rafrairal gmtcdaticnl mwfjres for ead~ pore! 71,e relttaal gaxalaiical analyses mast .show a mirtnrum: static safety factor of 1. s and a setsruc safety factor of 1.2 for ponds loofa! velxre failure venrtld he exp~tsl to cicu~e loss of life or serious property dmr~. Pond 014 may lr &alt rn dose proxrirtiry to an existirrgdzca4»tg/property orcrea: We also note that aU the sat~ter>r ponds evil! store venter; arul that tlx venter storage-will likely !x to a vertir~rl lxiglit greater thmz 10 feet, mtd suds sroragr rvi/l le lrlivrd a ctrtsnza7af enlzaebnart Far this reason, tle pat~isicns of Rule 4.OS.9(3J apply to these ponds, aryl t{x»efom the p/ovisiai of CR.S 37-87-1OS must be referatml Our recierv of CR.S 37-87-105 vtdiraies that tle aal matntg ngulatiats ai 4.05.6 and 4.OS.9 adaluately address tl~ prauisicrt ofCR.S 37-87-105, wdh one exmptun CR.S. 37-87-105 te~uires all pwed< m /x avrshuctel to a safety factor or 1.5. Please pnrr~ide the geatefz»ur/ arutlyyses requi~al by rule 4.OS.6(11 JGJtar e~uh paxL Due m tfx size of the ponds and tlx associataf amount of enter storage, tle gmta'rn:ica! analyses should fx des:gnel to mgt the regtrirerrtatts of Rule 4.05.6(1 ]JGJ. This gaxa!»raral analyse veould ensure omplimt~ venth Rules 4.OS.6(1 ]JGJ, 4.05.9(3), and CR. S. 37-87- ]OS. (Response submitted 07/15/99) The updated design and stability analysis documentation for the construction of Pond 012 was previously submitted in TR-11 as Exhibit 13-12.2, Proposed Pond 012 Design (6/28/99), and Attachment 13-13, Sedimentation Pond 012 Stability Analysis (5/26/99). The updated design and documentation for the construction of Ponds 013 and 014 are included in this PR-Ol for insertion into the PAP. Comment 36 (September 8, 1999) SCCprwidal stability analyses forpxrtds 013 and 014. T)xanalysis ntdirates that the anfzat,6rtau of pond 013 ve~ill hate a minirrnan static safety factor in exmss of 1. s. 7lx Diriuiort has no fun{xr tprKen7-s rcgmdmg the designs for pond 013. We vecwld like to rertnul SCC that tl~ er~vxmrrrrg npams disacsral rn thx Ramsnerlatiazs"sfeticru of rlx stability analyses slnuld Er submittal to tlx- Diuision wirli the as-built m~tifuadan far tlx ponds, if oat More. if mrtdiitau dtJferent thmt tlxue asswnel in d~ analyses are enmtma~ral dsnmg mnrMrctiat, ve s:~ggest tint SCC contact the Diu+ion aroreGately to dtsczus submqueru plmrs mtd ctrtsCrruYAaL The stability analysis for pond 014 »nGrntes a minvrnart static safety of 1.4. As discussal rn the Diviaats' onginal curnr~t, Rsde 4.OS.9(3J(aJ ra~cires a mv7nrttmr static safety faetrn of 1.5 for nrr(xxox7Srrarts venth art&mkmatts in exmss of ten fit. Phase refer to tlx original mraneu H36 and pnnade mt analysis or molifial arc<tnnritn plmu zPhid~ msrlt at a mv+nracn static safety factrn of 1. s. (Response to September 8, 1999 Comment) The stability analysis for sedimentation pond 014 has been revised and a factor of safety of 1.5 has been achieved. As stated in the recommendations section of the report, prior to construction of the pond, SOC will collect and test soil samples from the base and borrow areas to verify the subgrade and borrow material strength parameters used in association with the stability report.