2013-09-19_PERMIT FILE - M2012052 (3)

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Owner Information Providence Mine Providence Mining, LLC 100 Bennett Avenue Cripple Creek, Colorado 80813 Phone: 719 - 689 -2605 17 Storm Water Runoff ACTIV rTY o• t19 9.3 ACRES , 5 0 7 O rn ® 0 aa _ (� j Cn ci ROAD SURFACE CONSISTS OF POORLY GRADED MIXTURE OF ROCK UP TO 3 IN 0 N t_3 C= w M STRUCTURES,AND ROADS. DESCRIPTION OF NONDISTURBED VEGETATION AREAS O POTENTIAL POLLUTION SOURCES TO STORMWATER ORE (SOMETIME IN FUTURE), FUEL AND LUBRICANTS Exhibit X — Storm Water Runoff ACTIV rTY braun BRAUN ENVIRONMENTAL, INC. 355 South Teller Street Ste 200 Lakewood, COLORADO 80228 PHONE (303) 988 -7697 Murphy Mining & Exploration Creek Project Cripple Creek, CO Cripple � pp 9.3 ACRES August 27, 2013 Drawn by: Staff Date Rev: 9/13/13 Checked by: C.A. Braun SCS RUNOFF CURVE VALUES (CN) UNDISTURBED AREAS 42 DISTURBED AREAS 60 CONCRETE -ROOF 100 DISCRIPTION OF DISTURBED AREAS ROAD SURFACE CONSISTS OF POORLY GRADED MIXTURE OF ROCK UP TO 3 IN ENGINEER'S CERTIFICATION This report was prepared by the Engineer who's signature appears below or the engineer's direct su rvision). SIGNATURE: f ' No. 22601 q / DATE: / O 9875 9.870 9865 9860 9855 9850 9845 9895 9890 9885 9870 9865 9860 Total Surface Flow in Channel at Office - (Section B) 0.018 0.016 0.014 - I \ C 0.012 0.010 Flow 0.008 (CFS) Total Flow at Office 0.006 0.004 Note:Run -off on disturbed area exhibits I typ i ca I curve, whereas flow become steady once grassy areas becomes aturated. 0.002 0.000 f 5 10 15 20 25 -0.002 Time (hours) FLOW CURVE 1 — CALCULATED FLOW VOLUME OF CHANNEL FOR UP— GRADIENT DIVERSION — (SECTION B) — USCS METHOD Flow Rate Over Time - Section C 0.018 0.016 0.014 0.012 0.010 Flow Rate (cfs) 0.008 -Flow at Outfall 0.006 0.004 0.002 0.000 0 5 10 15 20 25 30 Time (firs) FLOW CURVE 2 — CALCULATED FLOW VOLUME OF SOUTH CHANNEL DIVERSION AT OUTFALL — (SECTION C) SCS METHOD _ Run —off — 100 Year Event 0.99ft Free Board Depth= 0.02ft IWldth =1.5ft Ground Surface , \ ,I/ � 0 5 10 Q= 0.006CFS Scale In Feet S= 0.04 NOTE: Roughness coefficient refllects shallow n= .04 flow conditions resulting tin nonlaminar flow SECTION C — ACROSS SOUTH RUN —(ON DIVERSION 0.85ft Free Board Run —off — 100 Year Event Depth= 0.05ft Width =0.5ft Road Surface, Q= 0.02CFS 0 5 10 S= 0.04 n= .04 i NOTE: Roughness coefficient reflects shallow Scale In Feet flow conditions resulting In nonlaminar flow SECTION B — ACROSS UPPER ROAD ANDI RUN —ON DIVERSION Stormwat\ Storage Depth (4 ") for 10 —year storm r Free BoardBoard�/�d 0 10 20 Scale In Feet SECTION A — ACROSS DUMP TOP AND STORMWATER STORAGE AREA GENERAL NOTES: RUNOFF FOR ALL AREA WEST OF RUN —ON DIVERSION IS ASSUMED TO FLOW ONTO WORK AREA AND IS INCLUDED IN CALCULATIONS IMPLIMENTATION OF DESIGN WILL OCCUR FOLLOWING FINAL APPROVAL BY DRMS ENGINEERING AND DESIGN NOTES: SITE DESCRIPTION PROVIDENCE MINE, TELLER COUNTY, COLORADO ACTIV rTY UNDERGROUND MINE TOTAL MINE PERMIT AREA 9.3 ACRES TOTAL DISTURBED A REP, HISTORICAL DISTURBANCE - 3 ACRES NEW DISTURBANCE- LESS THAN 0.25 ACRES SCS RUNOFF CURVE VALUES (CN) UNDISTURBED AREAS 42 DISTURBED AREAS 60 CONCRETE -ROOF 100 DISCRIPTION OF DISTURBED AREAS ROAD SURFACE CONSISTS OF POORLY GRADED MIXTURE OF ROCK UP TO 3 IN DIA. HISTORIC MINING HAS DISTURBED THE SURFACE IN THE AREA WITH DISTURBANCES INCLUDING WASTE ROCK PILES, LEVELED AREAS FOR STRUCTURES,AND ROADS. DESCRIPTION OF NONDISTURBED VEGETATION AREAS GRASSES AND SHRUBS, WITH SCATTERED TREES. POTENTIAL POLLUTION SOURCES TO STORMWATER ORE (SOMETIME IN FUTURE), FUEL AND LUBRICANTS LOCATION OF NON- STORMWATER DISCHARGE NO SOURCES KNOWN NAMEAND LOCATION OF RECEIV ING WATERS DISCHARGE TO NORTH - TRENDING UNNAMED GULCH THAT CONNECTS TO CRIPPLE CREEK: AN INTERMITTENT STREAM LOCATED 3,500 FEET DISTANT TO THE SOUTHWEST. RESULTS OF CALCULATIONS MAXIMUM SURFACE FLOWS - 2 -HR 100 -YR EVENT MEASURED AT STORMWATER DIV ERSION CONTROL POINT NEAR OFFICE RUN -ON EXCLUSION FROM UNDISTURBED AREA (NORTH 1.1 ACRES GRASS) MAXIMUM FLOW AND VELOCITY IN NORTH DIVERSION Q = 0.02 CPS V = LESS THAN 3.9 FPS GRADE= 4% CHANNEL CALCULATED AT OFFICE LOCATION - SECTION B) RUN -ON EXCLUSION FROM UNDISTURBED AREA (SOUTH 0.4 ACRES GRASS) MAXIMUM FLOW AND VELOCITY IN SOUTH DIV ERSION Q = 0.006 CPS V = LESS THAN 1.0 FPS GRADE= 4% CHANNEL CALCULATED AT END OF DIVERSION - SECTION C) RUN-ON EXCLUSION FROM DISTURBED AREA (HISTORIC 0.12 ACRES ROA DIWORK A REA ) NEW PRECIPITATION WATER GENERATED BY OPERATION 2.48 INCHES PRECIPITATION PRODUCES 444 CU FT FOR 10 -YEAR EVENT (NEW DISTURBANCE) (CN= 100) (BUILDINGS AND CONCRETE SURFACES ASSOC WITH CURRENT OPERATION - 2150 SO FT TOTAL) VOLUME GENERATED ON OLD DUMP SURFACE- OLD 2.48 INCHES PRECIPITATION PRODUCES 170 CU FT FOR 10 -YEAR EVENT DISTURBANCE (CURRENT WORK AREA) (CN= 60) TOTAL AREA - 12,000 SQ FT TOTAL CALCULATED STORMWATER GENERATED WITHIN 615 CU FT (SUM OF BUILDING RUNOFF PLUS HISTORIC GROUND SURFACE) CURRENT WORK AREA (10- YEAR STORM) RUN -OFF STORAGE AREA CAPACITY 2,050 CU FTATA DEPTH OF 9 IN ANTICIPATED DEPTH OF FILL OF 4 INCH FOR 10 -YEAR EVENT FACTOR OF SAFETY OF 3 INCLUDES VOLUME FOR NEW RUNOFF ASSOCIATED WITH PERMITTED OPERATION A ND HISTORIC RUNOFF THAT OCCURRED PRIOR TO OPERATION DESIGN DETAILS 1. WHILE THE SITE IS STILL IN EXPLORATION STAGE, THE LOCATION OF A HYPOTHETICAL TEMPORARY ORE STORAGE PAD IS SHOWN AND IS INCLUDED WITHIN THE STORMWATER CONTAINMENT AREA. THE STORMWATER CONTAINMENT AREA CONSISTS OF A DEPRESSED AREA LOCATED ON THE WORKING SURFACE THE STORAGE IS A NON- BERMED GENTLY SLOPING DEPRESSION WITHIN THE WORKING AREA DESIGNED TO CONTAIN 3 TIMES THE CALCULATED VOLUME GENERATED BY THE 10 -YEAR EVENT. THE DESIGN OF THE RETENTION AREA BOTTOM AND SIDES IS SUCH THAT IT IS ANTICIPATED THAT STORMWATER RELEASE WILL BE VIA INFILTRATION. PER THE DESIGN, A FREE BOARD OF 0.4 FEET IS MAINTAINED ALONG THE WESTERN EDGE A sAFETY BERM BERM DESIGNED TO MSHA SPECIFICATIONS IS LOCATED BEYOND, HAVING A HEIGHT OF 1.5 FEErANDA WIDTH OF NO LESS THAN 0.4 FEET ATA DISTANCE OF 1.5 FEET BELOW THE BASE THE BERM IS LOADER PLACED, WITH SIDES AT ANGLE OF REPOSE, AND IS TO BE MADE UP OF POORLY SORTED NATIVE MTERIALS SIZED FROM CLAY TO MINUS 4 INCHES IN THE LONGEST DIMENSION. THE BERMED IS TO BE MAINTAINED PER MSHA REGULATIONS. 2. DUETO THE SMALL SIZE OF THE SITE, ONLY ONE DESIGNED DIVERSION IS NECESSARY BUTA SECOND IS INCLUDED IN THE DESIGN PER DRMS REVIEW. THIS NORTH DIVERSION WILL DIVERT UP- GRADIENT WATER AWAY FROM THE WORKING AREA ALONG THE NORTH ACCESS ROAD. SEDIMENT RETENTION WILL BE GAINED ALONG THEACCESS ROAD WHERE THE SLOPE OF ITS SURFACE DECREASES. THE SOUTH DIVERSION WILL DIVERT UP- GRADIENT WATER AWAY FROM THE WORKING AREA TO AN EXISTING GULLEY LOCATED TO THE SOUTH. NO RETENTION PONDS, LINED OR UNLINED CHANNELS, RUN-ON AND RUN -OFF CONTROLS, OR OUTLET CHANNELS ARE NECESSARY FOR THIS SITE AS COLLECTED SURFACE WATERS ASSOCIATED WITH THE NEW DISTURBANCE WITHIN THE WORK AREA CAN BE DISSIPATmVIA INFILTRATION. UPPER DIVERSION ON SOUTH WILL REQUIRE MINOR UPGRADE, BUT CONSTRUCTION WILL BE PERFORMED IN SUCHA MANNER AS TO MINIMIZEANY INCREASE DISTUBANCE FOOTPRINT. 3. PERMANENT ORTE TEMPORARY SOIL STABILIZATION MEASURES SHALL BE APPLIED TO NEWLY DISTURBED AREAS NO LONGER IN USE WITHIN 30- DAYS AFTER USE HAS CEASED. IT IS RECOMMENDED THAT ANY PERM NENT SEED MIX BE APPLIED NO EARLIER THAN NOVEMBER AND NO LATER THAN MAY TO MAXIMIZE GERNINATION OF SEED. A DRMS APPROVED SEED MIX SHALL BE APPLIED AT RATES RECOMMENDED BY THE ENGINEER AND SEED VENDORS. 4 SEDIMENT TRENCHES ARE LOCATED DOWNGRADIENT OF THE DUMPAND WORK SURFACEAND HAVE BEEN INSTALLED AS A SAFETY BACKUP FOR SEDIMENT CONTROL THE DESIGN DEPTH OF THE TRENCH IS 1.5 -FEET. TRENCHES, AS ALL OTHER CONTROLS, A RE TO BE MAINTAINED DURING THE LIFE OF THE PROJECT. 5. AREAS WHERE FINE GRAINED SOILS ARE SUBJECT TO EROSION SHALL BE PROTECTED USING SILT FENCE PLANTED GRASSES, CRIMPED MULCH, OR OTHER SUITABLE MEANS.