1996-08-06_INSPECTION - M1977378

Home Browse Search

(Page 2) MINE ID # OR PROSPECTING ID # M-77-378 INSPECTION DATE 7/16/96 INSPECTOR'S INITIALS WHE OBSERVATIONS This inspection was conducted by Wally Erickson from the DMG field office in Durango, 484Turner Drive, Building F, Suite 101, Durango, CO 81301,phone (970)247-5193. The purpose of this inspection was to conduct a routine inspection of the Sunnyside Mine and to familiarize DMG staff with the Mine Remediation Projects resulting from the Consent Decree and Order with SGC and WQCD. Mr. Larry Perino, SGC, accompanied the DMG inspector through out this inspection. American Tunnel -Water Treatment Facility was operating. Trucks were observed, hauling sludge from the treatment ponds to the Mayflower Tailings Pond 4. Treatment ponds at the American Tunnel facility appeared to be functioning appropriately and well maintained. American Tunnel bulkhead valves were open, drainage from American Tunnel was entering water treatment facility. Discharge from the water treatment facility to Cement Creek is monitored per the requirements of COPS Permit No. CO-0027529. American Tunnel-Mine Waste Dump-mine waste from the American Tunnel operation had been previously stockpiled over historic tailings from pre-law lead carbonate mill at Gladstone. Mine waste had been removed and underlying tailings have been hauled to Mayflower Tailings Pond 4 for disposal. According to Mr.Perino, native ground underlying the removed tailings consisted of glacial deposit of materials containing iron pyrite. Grading appeared complete. Graded slopes blend with natural topography, ranged from 2H:1 V to 3H:1 V (overall 3H:1 V) and appeared stable, no evidence of slumping, settling or excessive erosion was located. Four seeps were observed along the base of the graded slope. Area of removed pre-law tailings from the lead carbonate mill was graded generally flat with drainage directed to the South Fork Cement Creek through several rip rap lined channels. Rip rap lined channels appeared stable. Straw bales have been installed at several locations within the drainage channels to treat drainage for sediment. Mulch material was evident through out the dump area. Clumps of sedges and willows have been transplanted in the north half of the area, transplanted vegetation showed high survival rate. Reclamation of the pre-law tailings pond from the lead carbonate mill, located on the south bank of South Fork Cement Creek, appeared complete. The area has been graded to blend with natural topography, vegetation was well established. Revegetation efforts included transplanting of approximately 24 spruce trees and 50 willow bushes. Transplanted spruce trees were salvaged from the Cement Creek diversion project and ranged from 2' to 10' tall. American Tunnel - Cement Creek Channel - waste rock material has been pulled back from the east bank of Cement Creek and regraded to approximately 2.5H:1 V slope. Regraded slope showed evidence of seeding, mulch and willow transplants. Lower 5' of 2.5H:1 V slope has been armored with appropriate rip rap lining to stabilize bank from high flows within Cement Creek. Regraded slopes and rip rap lining appeared stable and well constructed. Cement Creek channel did not appear to have been affected by regrading and rip rap installation activities. American Tunnel -Cement Creek Diversion, approved under TRA 9,was near completion. Pipe line cut and fill bench/access road was approximately 20' wide. Cut slopes appeared to be as high as 12' at 0.5H:1 V slope and stable. Drainage ditch had been constructed at the base of the cut slopes, underdrains installed at appropriate locations to ensure drainage for the road cut. Cut and fill material did not appear to have impacted the channel of Cement Creek. Black corrugated plastic pipe, approximately 15" diameter,had been installed to divert waters from Cement Creek to the existing water treatment facility. Two access locations have been constructed to allow inspection and maintenance of the buried diversion culvert. Sediment sump and debris screen were intact at the diversion culvert inlet. Operator indicated that de-icing equipment may be installed at culvert inlet to ensure culvert inlet remains open during winter season. Concrete foundation for diversion head gate was installed, diversion boards were not present. Channel of Cement Creek has not been reduced or constricted by construction of diversion head gate. Disturbance to Cement Creek by construction of the diversion head gate,appeared minimal. Approximately 20%of flow of Cement Creek was observed entering the inlet of the diversion culvert. Flow rate entering the diversion culvert was visually estimated at 50 gpm. Diverted flow was discharged at the diversion overflow outlet. Discharge from the diversion overflow outlet appeared equivalent to the inlet flow. Diversion overflow outlet was well armored with appropriate rip rap lining. Evidence of erosion was not found at the outlet of the diversion overflow. American Tunnel -Borrow Source Area reclamation appeared complete. Slopes have been graded to blend with natural topography and appeared to range from 1.5H:1 V to 3H:1 V. Graded slopes were well vegetated and appeared stable, no evidence of slope movement or excessive erosion was observed. Terry Tunnel - Primary Location of Alkaline Injection - Two water treatment ponds appeared well maintained and functioning appropriately, ponds were not discharging during the time of this inspection. Sludge from the ponds is trucked to Mayflower Tailings Pond 4. Historic mine waste was dumped off of the portal bench, resulting in steep slope conditions along Eureka Gulch. Operator indicated that historic mine waste may include timbers, mining equipment and garbage which may impede regrading of the pre-law