Gunnison Copper Project
What is in-situ extraction and how does it work?
The term in situ means “in place” or in the natural or original position. This recovery method uses basic principles of chemistry and hydrology to extract copper from the ore body in the ground while preserving the land surface and quality of the surrounding groundwater. Gravity pressure is used to deliver a weak acid solution to the deposit. The acid dissolves the copper, creating a solution that is then pumped to the surface for processing.
Why is in-situ recovery the right approach for the Gunnison Copper Project?
In-situ recovery is a proven extraction method that has been effectively used around the world. Because of the economic and environmental benefits of in-situ recovery, this extraction method is the preferred way to extract minerals. However, copper oxide deposits that sit below the water table are very rare with most of the known deposits occurring in Arizona. A combination of geologic features are required in order to make in-situ extraction possible, including the presence of soluble copper oxide mineralization, extensively fractured host rock, and aquifer conditions that allow for both copper recovery and groundwater protection. All of these conditions exist at the Gunnison Copper Project.
How can you ensure the local groundwater is not affected?
Before extraction operations can even begin, Gunnison Copper must be able to demonstrate that the project will have no adverse effects on the quality of water. Protecting the water involves establishing appropriate hydraulic control – a process used in a variety of fields to control or contain solutions. Gunnison Copper will use hydraulic control to ensure acid solution does not migrate outside of the mine area. The process is highly regulated with stringent state and federal permits required before extraction can commence.
Some local geologic features add another layer of protection. In particular, the deposit is surrounded by rocks that are natural acid consumers.
The physical construction of the wells also is vital to protecting water. With multiple layers of well casings, including acid-resistant cement, the wells are fully insulated. The wells are pressure tested before extraction can commence, and follow up pressure tests are conducted at regular intervals during the life of mine. Each well also is fitted with an electronic real-time leak detector.
Once extraction is underway, Gunnison Copper will build an on-site water treatment facility. Water used in the extraction process will be cleaned using reverse osmosis, acid neutralization and micro-filtration, and then returned to the aquifer.
Will the surrounding community be affected by the project?
Gunnison Copper is expected to create about 108 local positions once the mine is fully operational. The project also is projected to generate US$756.8 million in economic activity in Cochise Country alone.
While Gunnison Copper will result in significant economic benefits for the region and the state, the project will have little to no impact on the daily or long-term quality of life for residents of Dragoon or other nearby communities. An in-situ operation produces very little noise, dust or light pollution. The Gunnison Copper Project will not contaminate any existing water wells.
Will you use a lot of water and/or dry up local wells?
Compared to conventional extraction, an in-situ operation uses very little water. Gunnison Copper’s projected annual water use will make it one of the most water efficient copper mines in the state and a low water use operation in general. Regional hydrological studies will be conducted to ensure that local water supplies are not affected.
What safety measures and regulations are in place?
Safety is our highest priority. In fact, our focus on health and safety extends to our employees and contractors, residents and businesses, and the environment. Safety measures developed for the operation of the Gunnison Copper Project adhere to all local, state and federal regulations. This involves implementing best practices in the planning, design and execution of our activities, such as those described above in the construction of our wells. From exploration to closure, Gunnison Copper will meet all regulatory requirements.
How many people will you employ?
Gunnison Copper will provide a significant economic boost locally and for the state. The W.P. Carey School of Business, Arizona State University, completed an Economic Impact Study in 2014 that projects an average of 819 jobs will be created statewide. Of those 800-plus jobs, 108 people will be employed directly at Gunnison Copper, working in professional, technical and administrative roles. The balance of the jobs includes vendors, suppliers and other local business opportunities.
Will any of these jobs be available to local people?
Gunnison Copper already employs contractors and people from Benson, Willcox, Dragoon, Bisbee and Tucson, and plans to continue to access the local talent pool. The final decision on all hiring will be based on qualifications and previous experience. Nonetheless, priority consideration will be given to qualified applicants, contractors and consultants from the local area. Gunnison Copper also hopes to provide necessary job skills training for local residents, and assist local companies in identifying and preparing for contract opportunities.
When will you start?
Work at the Gunnison Copper Project site actually dates back to the 1960s and 1970s. The most recent efforts to study and develop an in-situ copper recovery operation began in 2007. Since then, Gunnison Copper has conducted extensive drilling, metallurgic studies, hydraulic analysis, and a comprehensive prefeasibility study was released in January 2014 and updated in 2016. The project has now entered what is known as the bankable feasibility and permitting stage. Commercial production is scheduled to commence in 2018, subject to regulatory approvals and requirements.
How can I learn more about ISR?
One of the best resources in the country for learning about in-situ recovery happens to be located not far from the Gunnison Copper Project site. The Mining and Geological Engineering Department at the University of Arizona has for more than 100 years been providing education, research, and outreach focusing on the sustainable development of mineral resources.
Gunnison Copper is also happy to communicate with anyone about the project. Please send inquiries to: email@example.com
How does in-situ differ from open pit mining or fracking?
In addition to not leaving a permanent scar on the landscape, one of the most important advantages of in-situ extraction is that the process cannot create any acid mine drainage. In a conventional extraction scenario, such as an open pit, the digging process exposes rocks sitting underground for millions of years. These exposed rocks, which line the shell of the open pit, and are piled up in waste dumps and tailings piles, react with the atmosphere and the chemical result is the creation of acid. The acid drains into the groundwater that naturally flows through the pit. This is a serious problem. In fact, acid mine drainage is the reason for many of the super fund sites that exist in the United States today. Because in-situ does not disturb the host rock at all, and because hydraulic controls are in place during extraction, there is no possibility for acid mine drainage to occur at the Gunnison Copper Project.
Fracking involves drilling holes deep underground and then injecting solutions under very high pressure in order to release natural gas by breaking-up the surrounding rocks. One of the characteristics required to mine via in-situ recovery is that the host rock are naturally highly fractured. No fracking is involved with an in-situ operation and permit conditions require the project to operate under pressures low enough to prevent any fracking. The Gunnison Copper deposit has the natural geologic characteristic of existing fractured host rock. No further fracking of the rocks is required.