38 rosemont copper - a bridge to a sustainable future

Traffic

ReportTITLE: AZ 83 Roadway Assessment RELEASE DATE: July 2009PREPARED BY: Tetra TechBrief Summary: Arizona State Route 83 (SR-83) will

be a main transport corridor for the Rosemont Copper project, thus the current roadway geometry and safety conditions along SR-83 between Interstate 10 (I-10) and State Route 82 (SR-82) were analyzed. Final report results summarize four key areas: 1) an introduction and site description; 2) a SR-83 roadway assessment, 3) a comprehensive accident analysis of SR-83 and an accident database of State Route 77, and 4) potential roadway improvements to AZ-83.

TITLE: Traffic Analysis Report – Rosemont Copper Project

RELEASE DATE: April 2009PREPARED BY: Tetra TechBrief Summary: Tetra Tech completed a traffic analysis

to examine the existing traffic conditions along State Route 83 (SR-83), which will serve as the project’s major access route, and to assess potential future traffic associated with the operations and the surrounding area. The study found that existing and forecasted conditions have Level of Service values at or above acceptable levels for up to approximately 20 years. Two potential mitigation methods were discussed to alleviate traffic: 1) carpool management and staged truck deliveries, and 2) modifications to SR-83.

Technical MemorandaTITLE: Rosemont “T” Intersection Analysis –

Acceleration Lane RELEASE DATE: June 2009PREPARED BY: Tetra TechBrief Summary: This technical memorandum prepared

by Tetra Tech presents advantages and disadvantages of one of four design alternatives for the proposed

Traffic studies looked at existing traffic conditions in and around the Rosemont project and proposed alternatives .

Traffic

38 rosemont copper - a bridge to a sustainable future

rosemont copper - a bridge to a sustainable future 39

Primary Access Road “T” intersection that is associated with the Rosemont Copper project. The design alternatives included: 1) a three-way stop sign, 2) a speed limit reduction, 3) an acceleration lane with both 55 and 35 mph speed limits, and 4) a bypass lane. The acceleration lane with both 55 and 35 mph speed limits is the focus of this analysis. For both speed options, recommendations were made for the construction of an additional northbound lane and overall widening of the “T” intersection; appropriate signage and their breakaway capabilities; and roadside clearing of trees.

TITLE: Rosemont “T” Intersection Analysis – Bypass LaneRELEASE DATE: June 2009PREPARED BY: Tetra TechBrief Summary: This technical memorandum prepared

by Tetra Tech presents one of four design alternatives for the proposed Primary Access Road “T” intersection that is associated with the Rosemont Copper project. The design alternatives include: 1) a three-way stop sign; 2) a speed limit reduction; 3) an acceleration lane with both 55 and 35 mph speed limits; and 4) a bypass lane. A bypass lane alternative to the Mine Plan of Operations design is the focus of this analysis. In addition to adding a northbound dedicated acceleration lane along SR-83, the design would also include a two-foot buffer between the acceleration lane and the through traffic lane. The intersection would be widened to keep traffic from crossing over into the acceleration lane, creating a clean and efficient traffic separation.

TITLE: Rosemont Traffic Study – Additional ScenariosRELEASE DATE: February 2010PREPARED BY: Tetra TechBrief Summary: Three additional scenarios were analyzed

by Tetra Teach as a supplement to the Rosemont Traffic Study of April 2009 and their impact on SR-83 for Operations Year 5 and Operations Year 20: No carpool; 50 percent carpool; and 50 percent carpool with no Copper Concentrate Truck traffic. Level of Service (LOS) analysis of intersections and roadway segments followed the same methodologies presented in the April 2009 study. LOS analysis of intersections showed acceptable LOS for all scenarios under all analysis years.

TITLE: State Route (SR) 83 Scenic Road Evaluation for Rosemont

RELEASE DATE: May 2009PREPARED BY: Tetra Tech

Brief Summary: The Patagonia-Sonoita Road, which extends along State Route 83 (SR-83) and State Route 82 (SR-82), is designated as a scenic road. Local community members are considering the possibility of applying for a national designation. Based on the requirements for the state Scenic Road designation, the roadway was evaluated for possible effects of the Rosemont Copper project on this designation. In a technical memorandum, Tetra Tech concluded that the development of the Rosemont Copper project should not affect the current designation.

TITLE: State Route (SR) 83 School Bus Stop Improvements

RELEASE DATE: June 2009PREPARED BY: Tetra TechBrief Summary: A total of seven school bus stops

were identified along State Route 83 (SR-83), which is the primary access and transportation route for the proposed Rosemont Copper project. In this technical memorandum, Tetra Tech proposed turnouts that met all three national requirements, conforming to the Arizona Department of Transportation Roadway Design Guidelines section on pullouts (Section 105-4). Advantages and disadvantages of each were evaluated.

TITLE: State Route (SR) 83 School Bus Turnout Improvements

RELEASE DATE: June 2009PREPARED BY: Tetra TechBrief Summary: In a Tetra Tech technical memorandum,

potential improvements to the current school bus turnouts along State Route 83 were assessed and recommendations were made. The Vail School District is open to improvements and recommendations.

TITLE: Rosemont “T” Intersection Analysis – Stop Sign and Speed Reduction

RELEASE DATE: June 2009PREPARED BY: Tetra TechBrief Summary: Tetra Tech conducted an analysis to

assess potential traffic flow issues and to recommend designs that would allow traffic to safely merge from the Primary Access Road onto SR-83. The alternatives analyzed in this report were to add a three-way stop or have a speed limit reduction.

TITLE: Wide Load Truck Turnouts for State Route (SR) 83RELEASE DATE: June 2009PREPARED BY: Tetra Tech

Brief Summary: In a technical memorandum, Tetra Tech presented two potential locations for wide load truck turnouts along State Route 83 (SR-83) — one at milepost 55.4 near Sahuarita Road and another at milepost 47.2, just north of the proposed Primary Access Road. Recommendations focused on turnout width and length, clearing that conforms to established guidelines, and the need for appropriate signage.