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<br /> <br />Ridge Area has been completed and until certain stipulations relating to the <br />proposed backfilling plan for the Moffat Area have been satisfied. These <br />stipulations are set forth in Section XVII of this findings document. <br />The operation is in compliance with the requirements of this section. <br />XVI. Explosives - Rules 2.05.3(6) and 4.08 <br />Info-mation pertaining to the use of explosives at the Edna Mine is presented <br />in Volume 6, Section 3.2 of the original permit with updated maps submitted <br />with the permit renewal application. <br />The only substantive modification made to the blasting plan during the <br />previous permit term was to change the time periods when explosives would be <br />detonated. In response to changes made to Rule 4.08.3(2)(b)(ii), a minor <br />revision submitted by Pittsburg and Midway was approved by the Division on <br />May 20, 1986. The revised blasting plan specified that detonation of <br />explosives would occur only during the hours from sunrise to sunset. <br />The operation is in compliance with the requirements of this section. <br />XVII. Backfilling and Grading - Rules 2.05.3(b). 2.05.3 <br />The backfilling and grading plan for the Edna Mine is described in Volume 7, <br />Section 3.4 of the original permit and in Volume 2, Section 3.4 of the permit <br />renewal application. Pre~nining and postanining contours are shown on <br />Exhibits 3.3-5 and 3.4-1, respectively. <br />Backfilling and grading operations may be described as the active pits, and <br />other disturbed areas. When overburden is removed from a pit by dragline or <br />back hoe, backfilling is accomplished by casting material into the adjacent, <br />previously mined pit. Handling of the box-cut material and final cut <br />represent special-handling situations. In the Moffat Area the box-cut <br />material will be spoiled down-hill towards Trout Creek where there is <br />sufficient area, and up-hill away from Trout Creek where the mining operation <br />is close to Trout Creek itself. This will create an increase in the ground <br />elevation in the area of the box-cut of up to 45 feet, and the slope towards <br />the stream will be increased and lengthened, but will not exceed lv:3h <br />(Exhibits 3.3-3 and 3.3-4 ). Rule 4.14.1(2)(d) prohibits the permanent <br />disposal of box-cut spoil outside of the mined area unless the material is not <br />required to achieve approximate original contour. In addition, box-cut <br />material which is not placed within the mined area is considered excess spoil <br />and specific design and construction criteria are required by Rule 4.09.1 of <br />the Colorado Permanent Regulatory Program. Pittsburg and Midway has prepared <br />and submitted a stability analysis and hydrologic assessment concerning the <br />deposition of excess spoil outside the mined area of the Moffat Area which <br />partially satisfies the identified regulatory concerns. To fully resolve the <br />excess spoil stability concerns, Pittsburg and Midway has committed to five <br />(5) demonstrations prior to initiating placement of permanent excess spoil <br />outside the mined areas in the Moffat Area. Pittsburg and Midway has <br />committed to providing to the Division the following: <br />-38- <br />January 13, 1988 <br />