2023-04-19_PERMIT FILE - C1981010A ‎(38)‎

• Permit No: C1981010A
• IBM Index Class Name: Permit File
• Doc Date: 4/19/2023
• Section_Exhibit Name: 1.0 Introduction
• Media Type: D
• Archive: Yes

1.4.1.2 Roadway Regrading

For purposes of estimating reclamation cost, three types of roads have been identified at
Trapper Mine, which include access, haulage, and dragline walk roads. These roadways
are designed and constructed to minimize amounts of cuts and fills, which minimizes the
amount of backfilling and grading that would be necessary to return them to a satisfactory

contour. Caterpillar D10R dozers were selected as the most cost-efficient equipment, given
the average distances calculated. These push distances and volume calculations for the
roadways are based upon typical cross-sectional areas. These areas were applied to
projected road lengths during the worst-case year of 2023 as shown on Map M9. From
these values, regrade times, as shown in Table A-6, were calculated. Costs were also
included for ripping haulroads using a material seismic velocity of 5000 fps.

Trapper is careful not to introduce materials on roads that will require removal at a later
date. That is specifically why the use of ash on haul roads has not been pursued. Roads
are constructed of earthen fill and sub-base material with gravel on top. Scoria may also be
used if available. These inert materials are easily graded during reclamation, covered with
topsoil, and do not adversely affect the growth of vegetation. Post mining land use
requirements are not compromised.

Drainages affected by road fills include Far East Buzzard, Coyote, No-Name, Johnson, West
Pyeatt, Middle Pyeatt, East Pyeatt, Grouse, Sage, Oak, Flume and Deal.

1.4.1.3 Impoundment Regrading

Calculation of regrade times for existing and future impoundments is shown in Table A-7.
Impoundment volume calculations are shown in Table A-7 (1-2) of Appendix A. Many of the
impoundments were approved as permanent structures by the Division. As a result, they
will be left in place. Impoundments requiring reclamation include Far East Buzzard; Coyote;
Middle Pyeatt 1, 2, and 3; Sage, West Horse, Deal 1 and 2; Jeffway 1 and 2; and Deacon 1
and 2.

The earthen impoundments would be graded with dozers, filling back the areas from which
the material had been previously removed. Caterpillar D10T dozers equipped with a semi-U
blade were used to develop cost data and productivity. This regrading would establish the
approximate original contours in the affected areas.

1.4.2 Topsoiling

After regrading, topsoil from previously established stockpiles would be placed on all
disturbed areas, except for such minor disturbances as light duty access roads, where
topsoil was never removed. Topsoil replacement costs are summarized in Table A-9.
Productivity and cost values are for Caterpillar 637G scrapers, and a Caterpillar 5130
excavator with Caterpillar 777F trucks. These equipment types, and particular models, were
selected as a cost-efficient means of loading, transporting, and uniformly spreading the
topsoil. TALPAC software was used to determine scraper and truck/Excavator production
per hour. The areas requiring topsoil replacement would include all active, inactive, and
abandoned pits, and their associated roadways, impoundments, and the industrial complex
area.

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