Alternatives Shared with Cooperating Agencies

Proposed Action

Rosemont Copper Company (Rosemont Copper)

NA

Fully described in the 2007 Mine Plan of Operations and supporting documents

No Action

Council on Environmental Quality Regulations

NA

Baseline for effects

Rosemont Copper’s Alternative Responsive to Public Comments Includes:

• Modifying stormwater management around the tailings facility and placing additional drains through the waste and tails (instead of the Central Drain); increasing the number and size of stormwater retention ponds; realigning the pit diversion for water management in area of upper pit elevation
• Reconfiguring key plant facilities to better contain contaminants in the event of failure and enhancing facility stability
• Tailing storage staging to consolidate water management system
• Reorienting haul roads (may only be mitigation)

Rosemont Copper (July 2008)

Air
Heritage
Recreation
Water

• Changing access road alignment
• Phasing the placement of tailings
• Realigning west service road and utility corridor to maintain recreation access
• Modifying toe of the waste rock and tailings facilities to avoid some heritage resource sites

Tailings facility located in Sycamore Canyon. Tailings would be conveyed via a slurry line and then dewatered at a filtering facility in the canyon. Rock to create the buttress around the tailings would be quarried in the vicinity. Recovered water would be piped back over the ridge. Waste and heap leach facility located in Upper Barrel and Upper McCleary canyons.

Public Interdisciplinary Team (IDT)

Heritage Recreation
Riparian Visual

Tailings facility in Scholefield Canyon, with waste rock and heap leach facility in McCleary Canyon

Public & Cooperators

Heritage Recreation Riparian Visual

Tailings and waste rock facilities only in Barrel Canyon, leaving McCleary Canyon open.

Riparian
Visual

One right-of-way for utilities and roads

IDT

Land Use

Conveyor belt transport of tails

Public &

Air?

Compensatory land designation

Cooperators

Recreation Riparian Vegetation Wildlife and Habitat

Dam in Barrel Canyon

Public & IDT

This will eliminate water being released into barrel drainage and provides no operational value. However, Arizona Department of Water Resources has never given the U.S. Forest Service surface water rights; reservoir could harbor invasive species.

Hydrological conveyance of wet ore to west side

Public

Transportation

Expand size of tailings filter plant

Rosemont Copper

May not be an alternative element

Realign East Access Road to facilitate overlook of project site

Rosemont Copper

Relocate raffinate pond to use gravity flow

Rosemont Copper

Relocate thickeners to minimize potential for differential settling

Rosemont Copper

Noise

Sequenced blasting

Rosemont Copper

Likely to be mitigation

Submerge fill for fuel tanks

Rosemont Copper

Air

Likely to be mitigation

Place tails and waste in a horseshoe shape around Barrel Drainage

Interdisciplinary Team (IDT)

IDT

In order for there to be sufficient volume, the piles would need to extend to State Route (SR) 83. If all of the high land is eliminated as a water source, the riparian area in Barrel Canyon would become starved and die. The impacts of this alternative would likely be more than the Proposed Action (IDT meeting).

Relocate tails and waste to west side of ridge

Public & IDT

Rosemont Copper
IDT

Not financially feasible to haul waste rock over the ridge. Furthermore, Rosemont does not control enough claim area on the western slope of the Santa Rita Mountains to accommodate the volume of both waste rock and tailings.

Create a dome around project

IDT

IDT
Rosemont Copper

Technologically infeasible. This would require the construction of a structure that would be more than 1 mile in diameter. No such structure has been engineered (IDT Meeting).

Electric/trolley system or rail out of area

IDT

Rosemont Copper

Would require right-of-way access for private and state lands from the Coronado National Forest boundary to near Interstate 10 (I-10). The line would result in impacts above and beyond what is currently proposed (IDT Meeting).

Government/U.S. Forest Service (Forest Service) purchases the mine for U.S. future consumption

IDT

IDT

Does not meet the Purpose and Need and outside Forest Supervisor authority. This would likely require an act of Congress (IDT Meeting & Rosemont response table dated 4-22-09).

Mining through the ridge

IDT

IDT
Rosemont Copper

Would likely result in greater impacts to all issues of concern. Rosemont believes this to be Infeasible because of the additional requirements to blast, haul, and dump substantially more waste rock (Rosemont response table dated 4-22-09).

Remove ridge behind the pit

IDT

IDT
Rosemont Copper

Would result in greater waste rock to dispose of and a larger footprint and would be visible from Sahuarita and Green Valley (IDT). Furthermore, Rosemont believes this is not economically feasible because the mineralization does not extend west of the pit (Rosemont response table dated 4-22-09).

Keep all waste rock and tailings out of canyon bottoms

IDT

IDT

Would result in placing waste rock next to SR 83

Move electric underground

IDT

Rosemont Copper

This would result in greater impacts as a result of increased ground disturbance. Furthermore, the line would need to be cooled by oil and would pose a greater potential for environmental damage (Rosemont response table dated 4-22-09).

Relocate SR 83 or portions of it

IDT

Rosemont Copper

Outside the jurisdiction of the Forest Service and Rosemont. Arizona Department of Transportation has scheduled changes not associated with this project (Rosemont response table dated 4-22-09).

Shorten operation

IDT

Rosemont Copper

Not financially feasible. The cost to Rosemont would increase $500+ million for equipment such as shovels, haul trucks, milling equipment, additional infrastructure, etc. This would also result in the need for an increased footprint for the plant facilities (IDT meeting).

Use Central Arizona Project (CAP) water with groundwater backup

IDT

Rosemont Copper

Rosemont does not have water rights associated with CAP and can only purchase excess water allocations. Furthermore, Rosemont has already acquired legal water rights to their well field (Rosemont response table dated 4-22-09).

Use Old Sonoita Hwy

IDT

IDT

Would not alleviate use of the SR 83/I-10 interchange and much of SR 83 from the proposed mine to I-10. Furthermore, the character of Old Sonoita Highway is more of a rural arterial that serves rural homes (IDT Meeting and Rosemont response table dated 4-22-09).

Wet tailings

IDT

IDT

Would increase impacts to all significant issues identified during scoping, especially water resources. Furthermore, wet tailings would require substantially more area for the tailings facility (IDT Meeting).

Alternate mine site or ore bodies/ mine in a different area

Public

IDT
Rosemont Copper

Rosemont has a legal right to access the minerals associated with their claims. Therefore, this alternative does not meet the Purpose and Need. Furthermore, the Forest Service is required to consider all proposals for mining that meet the requirements under 36 CFR 228(a) (IDT Meeting & Rosemont response table dated 4-22-09).

Alternative processing technologies

Public

IDT

This alternative is too vague to address in detail. However, Rosemont has proposed to use contemporary mining technologies such as dry stack tailings (Rosemont response table dated 4-22-09).

Alternative uses of public lands

Public

IDT

Rosemont possesses legal mining claims where the project is proposed. Therefore, the Forest Service lacks the authority to deny a legally permittable mine with reasonable mitigation (IDT Meeting and Rosemont response table dated 4-22-09).

Create a lake with CAP water on west side of Santa Rita Mountains for recreation and process water

Public

Rosemont Copper

Excess CAP allocations have already been purchased for ground water recharge, and lakes would not create recharge—they would create a surface area for evaporation (Rosemont response table dated 4-22-09).

Create completely separate road access

Public

IDT

Rosemont is proposing to construct a separate access road from SR 83 (IDT Meeting).

Extend mine project to 40 to 50 years/modified timetable

Public

IDT

Rosemont Copper

This would increase the duration of most impacts rather than mitigate them. Furthermore, this is considered financially infeasible because the life span of most mining equipment is approximately 20 years. Therefore, this would result in the need to buy new trucks and processing equipment halfway through the life of the project (IDT Meeting).

In situ mining

Public

Rosemont Copper

This is technically infeasible because it will not work on a sulfide ore body. Furthermore, this technique has never been commercially proven (Rosemont response table dated 4-22-09).

Limited project—limit to fee simple and patented mining claims

Public

Rosemont Copper

The largest contiguous parcel of land consists of a combination of both patented land and Bureau of Land Management land and is located north and west of the pit area. After evaluating storage volume of this area, it would fit, at the most, 852 million cubic yards. This is insufficient for this operation (Rosemont letter dated 5-29-09 with figures in support of statement).

Mechanical conveyance of ore to rail head/rail or trolley transport of ore, spoils, and tailings out of area

Public
IDT

Rosemont Copper

Technically infeasible because no existing conveyor technology exists for the size conveyor that would be needed. Furthermore, Rosemont does not control right-of-way or land from the proposed project site to the nearest rail head in southern Tucson. Financially infeasible; may not be possible to get approval for pipeline to connect at current port, cost prohibitive to acquire the right-of-way (IDT Meeting).

Mine in a different location

Public

IDT

Rosemont has a legal right to access the minerals associated with their claims. Furthermore, the Forest Service is required to consider all proposals for mining that meet the requirements under 36 CFR 228.

On-site high-pressure high-temperature leaching technology

Public

Rosemont Copper

This is technically infeasible because it will not work on a sulfide ore body. Furthermore, this technique has never been commercially proven (Rosemont response table dated 4-22-09).

Reclamation—create a lake out of pit

Public

IDT

A lake created in the pit during reclamation would not be safe for recreational boaters. Therefore, it would serve no purpose (Rosemont response table dated 4-22-09).

Reclamation with solar farm

Public

Rosemont Copper

Rosemont willing to explore this idea; however, this alternative element does not create a trade-off between impacts to different resources (Rosemont response table dated 4-22-09).

Relocate tails and overburden to other Green Valley mines and Twin Buttes Mine

Public

Rosemont Copper

Impractical because of distance, increased impact to Santa Rita Experimental Range, energy costs, and lack of existing conveyor technology. Furthermore, these mines are controlled by competing mining companies (Rosemont response table dated 4-22-09).

Remove all tails from public land

Public

Rosemont Copper

Not financially feasible because of the volume of tailings (Rosemont response table dated 4-22-09).

Reopen closed copper mines

Public

Rosemont Copper

Rosemont does not own any of these other operations (Rosemont response table dated 4-22-09).

Ship tailings to Canada

Public

Rosemont Copper

This is not financially feasible

Sublevel caving mining/vertical crater retreat

Public

Rosemont Copper

The type of ore body owned by Rosemont is not conducive to this type of mining (Rosemont response table dated 4-22-09).

Suspend mining during high winds, extreme drought, excellent “seeing conditions,” and/or at night/daytime operations only

Public
IDT

Rosemont Copper

This is technically infeasible because machines cannot be turned off easily/daily. Processes are continuous-flow processes that are not amenable to being shut down daily. Furthermore, because of large capital costs, it is financially infeasible not to operate the mine 24 hours a day. This is the standard practice for large, open pit mines (Rosemont response table dated 4-22-09).

Switch proposed primary and secondary access roads/loop road circulation system/in from SR 83 out through Santa Rita Road/expand and use secondary access

Public
IDT

IDT
Rosemont Copper

Impacts resulting from the combination of the construction of a road over Gun Site Pass sufficient to support primary access and impacts resulting from additional traffic through the town of Sahuarita would likely create additional impacts on top of what is already proposed. The west access road would have to be completely upgraded to handle loaded traffic in either direction. The overall impact of this would be greater than the proposal (IDT Meeting and Rosemont response table dated 4-22-09).

Tunnel through the Santa Rita Mountains

Public

Rosemont Copper

While some utilities could be located in a tunnel through the upper portion of the Santa Rita Mountains, it would be cost prohibitive to mine the ore body via a tunnel (IDT Meeting & Rosemont response table dated 4-22-09).

Underground mine

Public

Rosemont Copper

Ore grades are not high enough to sustain economic viable underground operation. This would also not significantly reduce the amount of tails or waste (Rosemont response table dated 4-22-09).

Use Box Canyon road

Public

IDT

Construction of a road in Box Canyon, suitable for large trucks, would likely disproportionately increase impacts to popular recreation areas, sensitive riparian areas and animal species, and population centers such as Green Valley (IDT Meeting).

Use CAP water

Public

Rosemont Copper

CAP is not a reliable source. Outside the jurisdiction of the Forest Service to require this of Rosemont. Furthermore, Rosemont has already acquired legal water rights to their well field (IDT Meeting and Rosemont response table dated 4-22-09).

Use Helvetia Mine road

Public

IDT

Impacts resulting from the combination of the construction of a road over Gun Site Pass sufficient to support primary access and impacts resulting from additional traffic through the town of Sahuarita would likely create additional impacts beyond what is already proposed (Cooperators and IDT Meeting).

Use high-pressure/high-temperature leaching

Public

Rosemont Copper

Because of low acid generation (pyrite) of the ore, it is not amenable to the high-pressure concentrate leach method (Rosemont response table dated 4-22-09).

Use ocean water for operations

Public

Rosemont Copper

This would require infrastructure that would make the project financially infeasible (Rosemont response table dated 4-22-09).

Use of solar, wind, natural gas, or geothermal energy

Public

Rosemont Copper

Tucson Electric Power is required to use 15% renewable energy by 2015 (?) and Rosemont has proposed solar in the Mine Plan of Operations (Rosemont response table dated 4-22-09).

Use Rosemont Junction road

Public

Rosemont Copper

Use sinking mine shafts to subterranean levels

Public

Rosemont Copper

Not suitable for this type of ore body; the ore is disseminated, rather than in veins or isolated zones (Rosemont response table dated 4-22-09).

Land Exchange

Public & IDT

IDT
Rosemont Copper

Does not meet the Purpose and Need and does not decrease impacts. May also be outside Forest Supervisor signing authority (IDT Meeting and Rosemont response table dated 4-22-09)

Rail transport of ore, spoils, and tailings

Public & IDT

Rosemont Copper

Financially infeasible; may not be possible to get approval for pipeline to connect at current port, cost prohibitive to acquire the right-of-way (IDT Meeting).

Use gray water

Public & IDT

Rosemont Copper

Not able to gain legal access to this water; Sahuarita uses theirs, and Green Valley leased all of theirs to private party for foreseeable future (IDT Meeting).

Use waste rock for industrial uses

Public & IDT

Rosemont Copper

Has been tried at Sacaton, and there has not been enough demand to reduce any impacts (IDT Meeting).

Backfill, continuous backfill, or partial backfill

Public, Cooperators,
IDT, & tribes

IDT
Rosemont Copper

It will take 20 years to excavate the pit, 15 to refill; effects on most resources will increase in duration, result in questionable stability, and increase resource use (fuel); concurrent reclamation would not occur, and effects are likely to be worse than Proposed Action. Furthermore, the configuration of the ore body does not allow for a continuous backfill like a coal bed (IDT Meeting and Rosemont response table dated 4-22-09).

Use Cienega Creek as primary water source

Public

IDT
Rosemont Copper

Rosemont does not have water rights associated with Cienega Creek. Rosemont has already acquired legal water rights to their well field. Furthermore, this would likely impact habitat for the endangered southwestern willow flycatcher and Gila topminnow. Other sensitive species could be impacted as well (IDT Meeting).