2018-04-02_REVISION - C1982056 - Laserfiche WebLink

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Response: - The NMD Power Borehole was permitted under TR00-37 in 2000. Review of the revision submittal materials does not identify a specified borehole depth, however, the reclamation cost estimate indicates 157 cy of grout to seal the borehole, which is 24" in diameter. Using these two figures, a rough depth of 1,350 feet is indicated. The referenced page has been revised to reflect this estimated borehole depth and copies of the revised page accompany these responses for replacement in the PAP. 35. Section 2.05.3(5) of the Permit regarding topsoil handling at the site refers to Section 2.05.4 of the Permit to address the requirements of Section 2.05.3(5) and then provides details about topsoil salvaging at some of sites throughout the Permit Area. Section 2.05.4 of the Permit does not discuss the specific methods used to strip topsoil. In accordance with Rule 2.05.3(5), please update this section of the permit to discuss topsoil stripping methods. Response: - The referenced sections address the applicable regulatory requirements for information on the areas and amounts of soil material recovered and stockpiled (2.05.3(5)), and subsequently removed from stockpile and replaced (2.05.4). Review of these sections indicates that the only thing possibly lacking is a description of the mechanics of soil salvage, stockpiling, removal from stockpile, and replacement. A brief description addressing the mechanics/methods has been added to Section 2.05.3(5) and copies of the revised text pages accompany these responses for replacement in the PAP. 36. Rule 2.05.3(5) requires the permit narrative to specify the depth of material to be salvaged from all disturbed areas. This section of the Permit only specifies the depth of soil removal from some of the disturbed areas but not all of them. At this point, for the current disturbed area, the topsoil is already stripped and placed in topsoil stockpiles listed on Table 49A of the Permit and depicted on Map 29 so the depth stripped is irrelevant. Map 17 shows the pre -mine topsoil thickness for the permit area based on the soil mapping unit. This map should be consulted to ascertain the average topsoil depth to be stripped from fitture disturbed areas. Please update Section 2.05.3(5) of the permit to discuss how the depth of topsoil to be stripped at a site is determined based on the soils information provided in Rule 2.04.9. Response: - The soils mapping and soil unit characteristics provided by Map 17 and the Section 2.04.9 provide a general reference relative to soil depths. Soil depths, however, can be highly variable dependent on topography, aspect, and other factors, and as a practical matter, surface disturbances may impact multiple soil units, depending on their location. TC's normal practice is to salvage all reasonably available topsoil materials, based on the visual soil characteristics observed during stripping operations. The criteria for soil recovery normally include observed color, texture, and plant rooting depth. When permitting information is provided to the CDRMS for any new disturbance, soil recovery estimates are typically based on the soils mapping, unit descriptions, and our previous (if any) field experience in the general vicinity of the proposed disturbance area. The additional text description referenced in the previous response includes information on determination of soil recovery depths. Rule: 2.05.3 (4)(a) -(d) 37. In Section 2.05-76.1 through 2.05-84, there seems to be duplicate information and outdated pages. Please address the following.• a. Please clarify Exhibit 8C (1). Was this structure ever built? b. In the narrative (Section 2.05-76.1 through 2.05-84) for the following ponds, please insert the Exhibit member and information as to the design precipitation event (for example: l0yr/24 hr or 25yr/24hr): i. Pond B ii. Pond C iii. Pond D iv. Pond E V. Pond F vi. Pond G vii. Pond T viii. FCB Treatment Facility