Prefeasibility Access Road Design-Revised
3
Project Authorization
Rare Element Resources contracted with HDR|Stetson Engineering in July 2012 to
complete updates to the prefeasibility access road design, further the survey and
design of the access road and provide a technical memorandum of pros and cons to
be submitted to the USFS.
II
DESIGN CRITERIA
Maximum Load Requirements
For determining load criteria, specifications from WYDOT, USFS, and Crook County
were considered. The WYDOT 2010 specification is used for the sizing and loading of
the truck. Crook County has adopted WYDOT standards concerning load
requirements. The design vehicle is described in the table below.
Design Vehicle per State, Federal, and County Specifications
Vehicle Type
Tractor + Double Trailer/Train
Maximum Length Combined Axles
81 Ft.
WYDOT Spec.
Gross Design Load
117,000 lbs
Number of Axles
9
Estimated Max. Payload
35 Tons
Federal Spec.
Gross Design Load
117,000 lbs
Number of Axles
9
Estimated Max. Payload
35 Tons
County Spec.
Gross Design Load
Adopted State Regulations
Number of Axles
Adopted State Regulations
The total length of the truck from the first set of driving wheels to the back of the
trailers can not exceed 81’. There is not a maximum total length of the truck
defined. Exhibit H-1 Rev. 1 in Appendix H shows a figure of the design truck
dimensions.
The estimated maximum payload was determined by reviewing tare weights for
trucks that matched the design vehicle. From the sample data, the average empty
truck weight was 46,500 lbs, making the maximum payload approximately 35 tons.
Special permits are available for purchase through the Wyoming Department of
Transportation. The maximum gross weight with a special permit is 150,000 lbs,
which would allow an estimated payload of approximately 50 tons. The design
vehicle loading is calculated assuming no special permits will be acquired.
