2010-12-17_REVISION - C1981019 ‎(116)‎

• Permit No: C1981019
• IBM Index Class Name: Revision
• Doc Date: 12/17/2010
• Doc Name: Exhibit 6 Item 8 Addendum to Pre-Feasibility Report
• Type & Sequence: PR3
• Media Type: D
• Archive: No

Addendum to the Collom Area Geology Pre - Feasibility Report
9 5.0 Coal Reserve and Reserve Estimates
5.1 Resource and Reserve Parameters
HGC estimated in -situ coal tonnage across the Collom Mine Area using the
geological resource model. Within this report, all estimates of coal tonnage
represent in -situ coal tonnage with coal quality estimates performed on an as-
received moisture basis Table 5.1 lists key resource and reserve parameters
applied to tonnage estimates.
The distances used to report measured, indicated and inferred coal resources
as well as proven and probable coal reserves reflect the distances used in the
"2005 Year -End Resource and Reserve Report for the Colowyo Mine ".
HGC relied upon the 2003 Edition, "Australian Guidelines for Estimating and
Reporting of Inventory Coal, Coal Resources and Coal Reserves" to define
terminology used to classify and report coal tonnages. These guidelines were
written in support of the JORC code for resource reporting. HGC uses the
following terms for reporting coal tonnage: Inventory Coal, Coal Resources
• and Coal Reserves.
September 2006 Page 13 of 25
Table 5.1
Key Resource
and Reserve Parameters
Parameter
Resource Value
Reserve Value
Measured /Proved Radius of Influence
500 feet (1,000)
500 feet (1,000)
(effective DH spacing)
Indicated /Probable Radius of Influence
1,000 feet (2,000)
1,000 feet (2,000)
(effective DH spacing)
• Inferred Radius of Influence
2,000 feet (4,000)
n/a
(effective DH spacing)
Default Coal Density
Modeled Parameter
Modeled Parameter
Min. Surf Mineable Seam Thick
2 feet
2 feet
Product Moisture Factor
Total moisture + 0.75
Total moisture + 0.75
Product Ash Factor
As -Rec. Ash + 0.75
As -Rec. Ash + 0.75
Product Btu Factor
As -Rec. Btu - 160
As -Rec. Btu - 160
The distances used to report measured, indicated and inferred coal resources
as well as proven and probable coal reserves reflect the distances used in the
"2005 Year -End Resource and Reserve Report for the Colowyo Mine ".
HGC relied upon the 2003 Edition, "Australian Guidelines for Estimating and
Reporting of Inventory Coal, Coal Resources and Coal Reserves" to define
terminology used to classify and report coal tonnages. These guidelines were
written in support of the JORC code for resource reporting. HGC uses the
following terms for reporting coal tonnage: Inventory Coal, Coal Resources
• and Coal Reserves.
September 2006 Page 13 of 25