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• (Page 21 • MINE ID q OR PROSPECTING ID tl M-1999-058 INSPECTION DATE 8/23/00 INSPECTOR'S INITIALS RCO OBSERVATIONS This inspection was performed by the Division as part of its monitoring of Construction Materials 110 permits. The operator was contacted about the inspection time and date. Due to a late date schedule change on the part of this inspector, the operator could not be present at the rescheduled time. The Division inspectors were accompanied throughout the inspection by the operator's onsite representative (named on page onel. The permit ID sign was posted on the gate at the base of the ramp road which extends up to the portal from the public parking area. Several permit boundary markers were observed in the area of the portal and dump slope. There is significant pre-existing disturbance at this site, from historic marble quarrying and from the recent operations of the previous operator (Colorado Yule Marble Co.l. The permit boundaries of the present operation do not include the ramp road below the portal nor the most unstable part of the existing waste dump. The operator uses and maintains the access ramp road, but it is not within the permit nor is it required to be reclaimed after mining ceases. The most unstable part of the dump slope is outside the permit boundary, and is not being disturbed by this operator. It lies adjacent to the permitted portion of the dump, which the operator has only minimally affected to-date. The site is active: mine personnel were observed leaving the site for the day, the generator was running, and a marble product sale occurred during this inspection. Most activity occurs underground, including actual quarrying of blocks, sawing of slabs and smaller dimension product, equipment storage, process water sump locations, limited waste material storage, and tube/fluid storage location. The marble block removal is creating a couple large galleries at or below the floor elevation elsewhere in the quarry, and proceeding toward the south. No mining is occurring from the upper, south portal area at this time. All access and haulage occurs through the floor level portal on the north. The diesel storage tank is outside the north quarry portal, within a geomembrane-lined berm. The liner appear to be competent in that it is presently impounding water, however it should be maintained: the operator should empty the water from it and pull up the north end of the liner where it has slumped, exposing the earthen berm. The diesel generator is located in asemi-trailer parked near the fuel tank. It does not exhibit any leakage, there is no hydrocarbon-stained soil evident. The sediment pond down the waste slope is still in the same condition it was in last year at the time of current permit issuance: containing numerous large marble blocks from the previous operator's activities. Its capacity is therefore reduced, but it is not known if its integrity is compromised. The operator has not affected the dump slopes above this pond structure, not discharged water here either, but the pond should be improved and maintained to ensure its future functioning, including its ability to control sediment from storm-related runoff. The upper dump slope, on the south end of the permit area, is still unaffected by mining operations. The surface discharge pipe for dewatering underground sumps was observed extending out of the south portal and toward the east (where it empties into Yule Creek, according to the operator's discharge permit with CDPHE/WOCDI• The roads used by the mining onsite are steep and constructed from existing dump rubble. A siginifcant fraction of this rubble is composed of marble fines, which are distributed throughout the dump. During storm events the marble fines appear to easily saturate and flow. Areas of the road exhibited gullying up to 6 inches deep. There is a low sediment and stormwater control berm extending across the width of the pad near the north portal, which was designed to direct all runoff and transported sediment into the portal and to an underground sump. The berm's location is at the extreme downstream end of the operations pad and onsite road. The capacity for sediment catchment is reduced, since much sediment has been deposited behind the berm. This control structure should be cleaned out, and perhaps given even more freeboard, to ensure that it continues to function properly. The operator may consider constructing additional berm-type structures at locations farther up the road, to the south. (These items were discussed in the 613/99 inspection by the Division.) The sediment berm itself did not exhibit breaching or erosion at the time of this inspection.