APPCOR12291 - Laserfiche WebLink

Home Browse Search

MR. MIQ3AEI, SAVAGE Page 2 January 7, 1981 3) The diesel storage area no longer serves this function and has not been in use since approximately September of 1980. Also, a berm surrounding the diesel storage area is in place which serves both to confine water which falls into the area and divert water away from the area. Therefore, it appears adequate sediment control of this area exists at the present time. An inspection of the area will confirm this statement. 4) Bob Liddle's ca~anents from a mr~un of December 8, 1980. 1. The two ditches in question have been redesigned after each of the drainage areas were extended to take into account the extension areas at the end of the ditches. However, the areas were replanimetered and the drainage areas of each are smaller than put forth in flue armnflrtnnt. They are: ditch 22-D4 - 25.05 acres; ditch 22-D6 - 73.7 acres. There- fore, both of these ditches will have been designed in a very conservative fashion. F~checlced Design Ditch: 22-D4 Description: Diversion above pit Area Drained: 25 acres Grade: 4 percent Peak Discharge: (32(1.19)(1.22) = 46 cfs Ditch: 22-D6 Description: Diversion above pit Area Drained: 99 - 100 acres Grade: 7 percent Peak Discharge: 138 cfs As can be seen, the peak discharge used in the original design are much greater than for the recalculated ones, therefore no change in design is put forth by TBM for these two ditches. 2. Sandstone riprap will be placed at the terminus of ditch 22-D6 to reduce the outgoing velocity. The rock will be obtained from the sandstone unit encountered during mining and will be approximately 2-4" in diameter. 3. The clay strata present at the mine will be used to create a liner underneath the rock lined outlet of Ditch 22-D4. The material will be hauled to the site, dumped and graded over the hillside. A dozer will be used to spread and grade the material and provide the cranpaction necessary to "seal" the material.