Governor Katie Hobbs should withdraw the State Land Department’s April 29 auction of 160 acres of State Trust Land requested by Toronto-based Hudbay Minerals to be used as for a mine tailings waste dump for the Copper World mine in the Santa Rita Mountains south of Tucson.
1. Selling this property facilitates the development of a mine that could drain more than 520,000 acre-feet of water from the aquifer beneath Sahuarita and Green Valley, portions of which are already in a state-classified subsidence zone.
A table in a 2022 Hudbay technical report indicates Copper World will pump 9,409 AF/year in Phase 1 of the project that lasts 20 years and 14,100 AF/year during Phase II of the project that will last 24 years. (An acre-foot is equal 325,851 gallons.)
2. Hudbay has no ability to replenish even a fraction of the groundwater it will pump in the immediate area with CAP water. Hudbay, and its predecessor Rosemont Copper, have stored 47,810 AF of CAP water since 2007. Nearly all of it, 46,127 AF, has been stored in Lower Santa Cruz Recharge Project in Marana, 45-miles north of where it will be withdrawn. Only 1,683 AF has been stored at the Pima Mine Road Recharge Project north of Sahuarita.
Hudbay is in its fifth year of a 10-year agreement to purchase 1,124 AF a year of low-priority (Non-Indian Agricultural) CAP water. But Hudbay only received the full allocation in 2022, no water in 2023 and only 843 AF in 2024 and 2025. The Colorado River crisis is reducing future CAP allocations and whether Hudbay will receive a future allocation and for how much is unknown.
3. Depleting the groundwater in this area will negatively impact that value of thousands of acres of nearby State Trust Land. The ASLD has not yet determined the financial impact of Hudbay’ groundwater pumping will have on the value of State Trust Land. (See Map 1 below.)
4. The mine threatens to destroy two Outstanding Arizona Waters on the east side of the Santa Rita Mountains where Hudbay plans to construct the massive Rosemont Pit. The pit will require dewatering wells that will draw down the regional aquifer. Davidson Canyon and Cienega Creek are protected by state law from any degradation. Together, they provide a renewable source of drinking water for Tucson. Heavy metals are already showing up in the water, possibly from ground disturbance caused by Copper World, according to water quality studies by the University of Arizona and the Pima County Flood Control District.
5. It’s too early to auction this property. Hudbay states in its 2023 Pre-Feasibility Study it has sufficient tailings capacity at two other dump sites for at least the first 15 years of mining.[1] (See Map 2 below.)
6. Hudbay says the 160 acres may not be needed. Hudbay claims it wants to purchase the State Trust Land to allow it to shift a third tailings facility that it may begin using in the 15th year of mining to the south, away from the Corona De Tucson community.
Hudbay, however, states it the Pre-Feasibility Study that it considers the third waste site as “optional”. “Hudbay believes that a preferable alternative location for tailings storage can be secured by that time.”[2]
If the third dump site is not needed, then there is no need for Hudbay to acquire the 160 acres.
7. Hudbay provides conflicting information.
The company hedges on whether the third dump site is optional by also stating in the Pre-Feasibility Study that even if it used all currently available dump sites, including the third site, it still wouldn’t have enough land to dump tailings from all the ore it expects to mine in the first 20 years of operations.
Hudbay states if it could obtain additional land for tailings disposal it could process another 41 million tons of copper ore into raw copper concentrate. “This material…remains an upside opportunity should Hudbay secure additional surface rights for tailings disposal.” [3]
The 160 acres could allow Hubay to process 41 million tons of ore, which would generate hundreds of millions of dollars in additional revenue.
8. The state-approved appraisal grossly undervalues the 160 acres at $993,000. The appraisal classifies the land as rural residential rather than as industrial land suitable for mine tailings. Acquiring the State Trust Land for less than $1 million would be a windfall for Hudbay because it would allow it to process additional copper ore worth hundreds of millions of dollars while shortchanging the State Land Trust.
9. Hudbay is for sale. The company has been for sale since 2023. Obtaining the 160 acres would “derisk” the mining project and increase the company’s overall value because it could potentially process additional copper ore. The state must not put the financial interests of foreign mining companies ahead of Arizona’s public schools, which are the primary beneficiary of land sales.
Conclusion:
The state must act in the best interest of the State Land Trust. Holding the land until it is needed and appraising the property as industrial land suitable for mine tailings would ensure the state obtains maximum value of the property. Conversely, if Hudbay never uses the northern tailings dump then the 160 acres could become valuable conservation land as a buffer between the Coronado National Forest and mining operations.
Hudbay plans to install three groundwater extraction wells at its SanRita West site and one groundwater well at SanRita South. Each well has a state Department of Water Resources permit for up to 1,500 AF/year, but that amount can by adjusted upward upon request. The state has conducted no analysis of the impact Hudbay’s pumping will have on the value of State Trust Land.
[1] Copper World Pre-Feasibility Study, July 1, 2023, Pg. 18-5.
[2] Ibid.
[3] Copper World Pre-Feasibility Study, July 1, 2023, Pg. 1-10
Maps:
Map 1
Hudbay’s groundwater wellfields are adjacent to State Trust Land
Hudbay’s groundwater production wells at SanRita West and SanRita South are adjacent to thousands of acres of State Trust Land in blue. Each square contains 640 acres. This is prime residential development land that will be impacted by Hudbay’s groundwater pumping. The northern half of the Santa Rita Experimental Range is in rose.
Hudbay plans to install three groundwater extraction wells at its SanRita West site and one groundwater well at SanRita South. Each well has a state Department of Water Resources permit for up to 1,500 AF/year, but that amount can by adjusted upward upon request. The state has conducted no analysis of the impact Hudbay’s pumping will have on the value of State Trust Land.
Map 2
Copper World won’t need the 160 acres for 15 years
The 160 acres would link Hudbay’s primary waste dump at the “F” parcel (Tailings Storage #1)), with Tailings Storage North that abuts Corona de Tucson. Hudbay states it has enough room to dump tailings for 15 years at Tailings Storage sites #1 and #2 and that it considers the north facility to be “optional” because it expects to find a better location for tailings in the future.
At the same time Hudbay states in technical reports that the northern site is “optional”, Hudbay is telling ASLD it plans to shift the north tailings waste dump south, away from Corona de Tucson if it acquires the 160 acres. However, it is under no legal obligation to do so.
Map 3
The 160 acres could help Hudbay generate a financial windfall
Hudbay’s 2023 Pre-Feasibility Study states the company could process an additional 41 million tons of copper ore worth hundreds of millions of dollars if it could acquire additional land to dump mine tailings. The 160 acres would allow Hudbay to process the additional ore, but doing so would prevent it from moving the TSF-N tailings dump away from Corona de Tucson.
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