It's Our Future: The Effects of Resolution Copper's Mine on Oak Flat

March 18th, 2022. By Ethan Tam '22

This article was developed off of the Inside SI article from the same author.

During X-Period on Tuesday, October 19, SI students and faculty gathered in Orradre Chapel to listen to those leading “The Fight For Oak Flat”-- a movement advocating for both indigenous and ecological preservation in Arizona.

Currently, Resolution Copper, one of the biggest mining companies in the world, threatens Oak Flat, the Apache tribe’s native land. In addition to religious liberty concerns, the company’s plan to utilize nearly as much water as the population of Tempe (160,000 people) is a significant environmental issue. Professor Wells, a Registered Geologist at the University of Washington, points out that the mine would exacerbate the current water shortage in Arizona. The state already has limited groundwater for its communities due to moisture deficits for the past 100 years. In its 26th year of a long-term drought, Arizona would have even less water because of the unusual amount of resources the mine requires.

Figure 1. Relative volumes of copper, tailings and material above ore deposit that would be disturbed due to block caving at the Resolution Mine. US Capitol is shown for scale.

Figure 2. USDA 100-year moisture index, showing much of Arizona has a moisture deficit, even when averaged over 100 years. Source, USDA, 2012, Forest Health Monitoring: National Status, Trends and Analysis.

Resolution Copper’s choice to lessen costs through block caving (a method that allows an ore body to collapse on its own weight by undercutting a large section of rock) would use about 775,000 acre feet of water over the course of years, which is far more than the typical mine. Professor Wells is most concerned about the company’s failure to evaluate future implications on water supplies, which has been an issue for many years. Based on projected models, there simply is not enough water for everyone.

Another concern is the plan to store nearly 1.5 billion tons of mine tailings (ore waste) in Dripping Springs Valley. Officials would transform the area into a dam, also known as the Skunk Camp Alternative. Toxins such as cadmium, iron, lead, zinc, and arsenic could leak out of the wastes of copper mines and into the environment, threatening the flourishing biodiversity of Oak Flat. Once toxins enter the food pyramid of an ecosystem, they threaten all species; also known as biomagnification, the concentration of toxins amplifies as organisms consume the other.

Figure 3. Visual of biomagnification in marine organisms with an example of mercury as a toxin.

Toxins accumulate from one organism to another, so those at the top of the food chain are most affected. Top predators in Oak Flat such as bears and foxes would die early from these toxins, causing an imbalance in the fragile ecosystem. This process can also be individually mapped through the biomagnification factor:


BMF - biomagnification factor

CB - chemical concentration in organism

CD - chemical concentration in organism’s diet

1. If BMF > 1, then substance/compound has biomagnified.

2. If BMF < 1, then substance/compound has not biomagnified.

Oak Flat would likely see BMF values approach 1 in species if toxins leak.

The high usage of groundwater and effects of biomagnification are only some of the many environmental concerns for the Apache tribe’s religious land. Both natives and other Arizona residents deserve a clean place to live, but Resolution Copper’s mine is a major obstacle to that.

Please sign and share this petition to protect Oak Flat:

Text “Sign PKBVKY” to number 50409 to help to send letters to elected representatives in support of the Apache tribe.

The dreams of the world lie within today’s choices to protect the Earth; advocating for Oak Flat is a crucial step for the rights of natives and the future of the human race.


Arizona State. “Arizona Drought.” Arizona State Climate Office, 29 Sept. 2021,

K.G. Drouillard, in Encyclopedia of Ecology, 2008

Oguche, Agape. “Biomagnification Definition and Examples.” Jotscroll, 4 Nov. 2021,

Rzymski, Piotr et al. “The chemistry and toxicity of discharge waters from copper mine tailing impoundment in the valley of the Apuseni Mountains in Romania.” Environmental science and pollution research international vol. 24,26 (2017): 21445-21458. doi:10.1007/s11356-017-9782-y

U.S. Congress. House Natural Resources Subcommittee. “Indigenous Peoples of the United States Hearing on the Save Oak Flat Act.” (Date: April 13, 2021). Text from: Federal Document Clearing House Congressional Testimony. Available from: Natural Resources; Accessed 11/6/21