REV10610

• Permit No: M1976027
• IBM Index Class Name: Revision
• Doc Date: 11/21/2000
• Doc Name: CRAIG PIT PN M 1976-027 TR 002 3RD ADEQUACY REVIEW
• From: DMG
• To: NIELSONS INC
• Type & Sequence: TR2
• Media Type: D
• Archive: No

• iii iiniiiiiiiii iii •
~ IATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman St., Raom 215 EwEp
Denver, Colorado 80?0) REC
Phone: [phone]-]567
FAX. (703) 8J2~8106 r~t~
" q~ 1 2opp
N0
November 15, 2000 1Miperalsvod~eologY
~~
DIVISION OF
MINERALS
GEOLOGY
R E C L A M A T I O N
MI NING•SAFETY
Divlalon n , ~
Mr. Chris Nofsinger ' -''
//~ R~II Owens
Nielsons, Inc. ~ ~ e_~_ Iq ~ / Governor
I : -,
P. Q. BOX 1660 - ~ ~ ' Greg E. 1Valcher
i': -" 4 ~ Esecwrve Dkeclor
Cortez, Colorado 81321 _ ~ ;', ~ C~i~_„~,_ ~~~ 2
"~ Michael B. Long
Re: Craig Pit, Permit No. M-1976-027, Technical Revision No. 2 Third Adequacy Review Divsn~n Director
Dear Mr. Nofsinger
The Division has reviewed Nielsons Inc.'s November 13, 2000 response to DMG's second adequacy review
letter for your Technical Revision No. 2 (TR-002) application to the Craig Pit permit. A couple of items
remain to be adequately addressed before the Division can approve the TR-002 application.
Nielsons, Inc. must respond to this letter, by noon of November 17, 2000. Failure to respond adequately,
or submit a written request for extension of the decision due date, by noon of November 17, 2000 may
result in denial of this application.
Adeauacv Comments
The east highwall is shown, on Exhibit C-2 Phase 2, to be maintained at a 1 /2:1 slope though the
reclamation cost estimate calculates grade reduction costs for this highwall based on reducing a vertical
highwall to a 2:1 slope. Please revise either the map or the cost estimate so they are consistent.
The heights for the north, east and west highwalls are shown, on the application maps, to be in excess
of 50 feet and as high as 100 feet, though the reclamation plan states a depth of gravel up to 50 feet
and the reclamation cost estimate uses heights of 50 feet or less to calculate material volumes for
highwall reduction tasks. Please see the enclosed copy of the reclamation cost exhibit with penciled in
corrections for average highwall heights and material volumes that correspond to those tasks. The
penciled in calculations also include a reduced figure for volumes required if all highwalls are maintained
at a grade of 1 /2:1 instead of vertical. Please revise the mining and reclamation plans to specify the
highwall geometry that is consistent with the maps and specifies whether the highwalls will be mined
vertical, or ai 1 /2:1. Also, revise the reclamation cost exhibit to be consistent with the revised plans
and/or revised maps.
The volume of material needed to fill the center deep pit, the north highwall and the south highwall is
significantly more than the volume of overburden material that is available on site. The volume of
material necessary to fill the center pit, as shown on Exhibit C-1 is calculated at approximately 50,000
c.y. The volume of material necessary to fill 450 feet of vertical north highwall, shown to be an
average of 80 feet in height, reducing it to a 2:1 grade, is calculated at 106,666 c.y. The volume of
material necessary to fill 350 feet of vertical south highwall, shown to be an average of 90 feet in
height, reducing it to a 2:1 grade, is calculated at 105,000 c.y. This results in a requirement of
261,666 c.y. of material needed for the proposed backfilling tasks. With an estimated 72,000 c.y. in
the southeast overburden stockpile, and an estimated 62,222 c.y. of in place overburden (average 10.5
foot depth) in the unaffected areas of Phase 2, there appears to be 134,222 c.y. of overburden
available for backfilling. This results in a shortfall of approximately 127,444 c.y. of fill material. When
the fill volume calculations are based on an assumption that all highwalls are maintained at a 1 /2:1