2015-01-26_PERMIT FILE - C1981012 ‎(8)‎

• Permit No: C1981012
• IBM Index Class Name: Permit File
• Doc Date: 1/26/2015
• Section_Exhibit Name: Section 3.0 Performance Bond Requirements
• Media Type: D
• Archive: No

Density Calculation Method Two
Product
Density (Ibs /cubic yard)
clean coal
1,457
washed coal refuse
1,916
topsoil stockpile no. 2
2,055
subsoil
2,132
gravel products
2,396 (averaged)
Other available sources of material densities were researched and reviewed to support
and evaluate the accuracy and validity of our on -site measurements. Many sources are
available on -line and our investigation indicates considerable variation of published
material densities. One source, Harmony Sand and Gravel, listed density values per
cubic yard for the various materials on the low side; coal, 1275 Ibs; topsoil, 1890 Ibs;
subsoil, 2106 Ibs; Another source, Simetric, revealed values on the high side; coal, 1862
Ibs; topsoil, 2105 Ibs; subsoil, 2430 lbs. It was also noted the CIRCES program used by
the Division returns a value for "Earth, loam" at 2100 Ibs /cu.yd. All soils at the New Elk
mine are a "loam" soils.
Based upon our on -site measurements and review of published material density
information, NECC believes that the material densities determined using Density
Calculation Method Two are accurate and representative of the material densities for
the purposes of reclamation cost estimating and these values should be used for current
and future cost estimate purposes at the New Elk mine.
As a result of review during TR -68, Response to Midterm (MT -6), it was determined that
a site -wide swell factor of 21.8% was reasonable and appropriate for topsoil at the New
Elk mine. Topsoil in its natural state is by definition calculated by multiplying area times
thickness and results in bank cubic yards (BCY). Topsoil that has been harvested from
the bank condition is swelled by 21.8% for RCE calculations and if placed in a stockpile, is
also assumed to revert to a volume more closely represented by the original bank cubic
yard volume once resident in the stockpile. Topsoil harvested from either its natural
state or from stockpiles is then swelled by a consistent factor of 21.8% to loose cubic
yards (LCY) for final reclamation purposes. Following this assumption prevents any
duplicity in the swell of the topsoil resource.
Revegetation Failure Rate Including a failure rate within the revegetation tasks of
CIRCES reclamation cost estimates is required at all Colorado coal mining operations.
Absent operator provided information, standard failure rates for the various coal mining
regions within Colorado are taken from a Division staff memo dated 2/9/1995.
According to the memo, NRCS regional offices were queried for their opinion and
estimate of revegetation failure rates. For the Trinidad /Canon City area, the failure
rates were estimated between 35 -65 %. At that time, no significant reclamation had
been done in the vicinity of the New Elk mine operation and certainly no data had been
collected to determine the success of any completed reclamation. Since 1995, a
Section 3.0 TR -68 9/29/2014