REV10759

• Permit No: C1982056
• IBM Index Class Name: Revision
• Doc Date: 8/25/2006
• Doc Name: Adequacy Review Letter
• From: DRMS
• To: Twentymile Coal Company
• Type & Sequence: TR54
• Media Type: D
• Archive: No

Jerry M Nettleton
Twentymile Coal Company
Page 2 of 3 pages
August 25, 2006
accordance with the requirements of this rule [Rule 4.03.1(1)(e)]. An option would be
to reduce the grades to result in no more than 300 feet of road with pitch grades in excess
of 10 percent within a 1000-foot reach.
Item 4. Rule 4.03.1(3)(d)(i). The specification for cut slopes are 2 horizontal to 1 vertical
in text on proposed page 2.05-70, but shown as I.5 horizontal to 1 vertical on Map EX49
I-1. A recommendation of 2 horizontal to 1 vertical is in the geotechnical report (page 2).
Please correct the drawing.
Item 5. Rule 4.03.1(3)(e)(i). There may be a requirement to widen the existing road in the
vicinity of the switchback (line 17, page 2.05-70). This conflicts with the statement made
on line 8 that there was no topsoil to salvage. Please reconcile the statements. Please
indicate that topsoil will be salvaged (as may be appropriate, perhaps stored in SF-6,
see Map 29).
Item 6. Rule 4.03.1(3)(e)(ii). Please include, in the detailed design of Map EX49 I-1 or
elsewhere, the recommendation contained in the geotechnical report (page 2) to bench
or key embankment fdls in the natural hillsides or existing embankment fills.
Item 7. Rules 4.03.1(3)(e)(iv) and 4.03.1(5)(6). Please add a statement, perhaps as a
note on Map EX49 I-], in the typical cut/fill cross-section, that the road structure
materials are to be free of acid- and toxic- forming materials.
Item 8. Rules 4.03.1(4) and 4.05.3(7). Acut-slope ditch cross-section is shown on Map
EX49 I-1, and the Haul Road C-1 ditch is shown on Map 24, Sheet 1 of 3, of the
application. However, no information (see Exhibit 8) was located on the design flows or
required dimensions of the ditch. Please identify the location of, or supplement the
application with, this information. Please include design of those measures taken to
prevent down-cutting of the ditch thalweg (concern of erosion in those portions of the
ditch with grades over 3%).
Item 9. Rule 4.03.1(4)(c). Please revise the design to discharge cut-slope ditch flows
prior to the switchback in conformance with this rule.
Item 10. Rule 4.03.1(4)(d). Please incorporate an adequate crown to meet the
requirements of this rule in the modification (perhaps a note on the cross-section on Map
EX49 I-1).
Item 11. Rules 4.03.1(7)(a)(iv), 4.03.1(7)(a)(v), 4.03.1(7)(a)(vi), and 4.03.1(7)(a)(ix).
Please identify the location of, or supplement the application with, the information
appropriate to these rules regarding reclamation of Haul Road C-l.