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JUN-16-97 I,ON 11:10 q J HgMMER CO INC ~7UN 16 '97 10~04gh1 DI~iMINERRLSsLG£OLOGY •4 .•~ •~ ~~ (Page 2) T1IN8 ID A Ok PROSPECTING ID C ~ 79-214HIt INSPECY'I017 DATE 21 OBSERVATIONS 6549599 P.08 P,7i11 :~ INSPSC1Vk' S I1PiTilWS ~~ This inspeci.ien vas conducted to determine the status of the storm water and sediment managemeht p; 3n approved by the Division of Minerals and Geology (Division) on February 26, 1997. The O;eretor was represented by Leela Pajasekar of Tuttle Applegate, Inc- The sediment control plan is referenced in Exhibit i of Che February Z7, 1997 agreement between the c:.:lorado !Lined Land Board (Board), the Division, and Rocky Mountain Rock Products (Operator!. Pursuant to the agreemene, the runoff control plan was to have been implemented to the Division's satisfaction by April 15, 1997- The Operator revised this plan on March 28, 1997, the Division issued a list of concerns with the revised plan on April i, 1997 and Che Operator responded to the Division'& issues on April 9, 1997_ In subsequent disctiasions with the Operator and the Operaeor'6 reDresentacive, Tuttle Applegate, 2ac_, the Division verbally approved various elements of the April 9, 1997 plea, A diversion structure near the entrance gate has not b9en approved. On April ie, 1997, the Operator submitted a schematic for this structure, the biviaion needs additional information re9ardin4 da;th and width of the structure which vas not clear from the schematic. with the ex+c~.ption of the entrance gate diversion structure, the revised sediment control plan has beep. implemented in the field. Some of the etruceuree do not, however, meet the design Crite:"ia. TheBe are a9 follows: Uoner B~_~j_ Channel: Ruaoff colleCte in Pond UBi, flows through a Z4" concrete culvert into a cr+:ill rip-rap armored stilling basin, and into Poad DS2. Runoff Prom eub•baeine 8 and B1 end overflow from the Pond U81 emergency spillway is intercepeed in a separate rip-rap lined channel xhich runs into the north side of Pond DB2, In the area where the chancel should Curn southward to enter Pond Q82, the rip-rap is not aligned with the channel. The ,.hannel in this area needs co De adequately ro•routed into Pond [T>!4 and armored with properly aligned rip-Yap. See Problem PB-1 on page 4 of this report. 2. &ntran__. ee Gat~,~edimenC Pond: This pond contained water et the level ~•t the discharge Culvert. The outside of Lhe south pond emban}ment is wet and soft. Si.ce this pond ie fed by a perennial spring, the south embankment x311 need to be buttressed with Coarse mecerial which allows for free drainage. Se0 Problem PB-Z on page 4 of this inepeeCion report. 3, Cy3~[prt !,+ e[ers: The Drainage Basin tfap received on April 14, 1997 called for discharg0 culvert diametero ae listed below, The culvert diameters measured in the field are listed ::or comparison. POND ID DISCHARG& CULVERT DIAMETER FI&LD MEASUR$D lin) (in) (iB1 2a 24 Dal 24 ie i'ID1 24 22 LBl 24 22 i,gj 2s 22 Except E+~r Pond DBl, the culvert diameters measured in Chv held are snu.llor than called For an t1.e deoiyn. Required corrsceiva setiene will be to either install the eppi'epriats sieed cttverta or demonstrate chat the exieeing ones will bo adequate. The adequacy o£ Che exiating C~+l~erte een be demonstrated by modelling Che design 10 year•Z4 hear hydroy:sph ehrough the ponds using culvert diameters measured in the field. Properly aired culverts muse be inscnlled aB aeon ae possible or a new zunoiP model which demonet~:atee that the exlating culverts ors adequate must be eubmiCtef and approved by the Div.aion as soon as possible. See Posaibis Violation Pv-1 on page 4 of this report. $Ipq~a~-, •, Hnillvave; The emergency cpillray arose seccionB wars field +:hseked with 100' -~- --,.,.._.._ <__ .w. .,,~ Le11. r.nt and LBl ware found tv be