When it comes to the environment, Rosemont has been thought through in ways that might surprise you.

The permitting and public review process was exceptionally thorough, lasting 12 years and involving 17 governmental agencies, more than 1,000 studies and a public comment period that generated more than 43,000 comments.

The result is over 5,000 inspections, surveys, sample events, reports or actions required by the Mine Plan of Operations, the 404 Permit, the Biological Opinion, the Historic Properties Treatment Plan, the Memorandum of Agreement, and more than 10 other state or locally-issued permits/certifications/requirements.

In the sections below, we share some of the steps and actions that Rosemont will take to comply with its permitting requirements and ensure adherence to world-class standards of environmental stewardship.

Air Quality – Breathe Easy

  • Rosemont is committed to minimizing potential impacts on air quality by using the best technology available. This will be reflected in to the selection of everything from the engines used in our large mining trucks to the dust collectors on process equipment. Air quality monitoring will be conducted in accordance with an air quality control permit issued by the Arizona Department of Environmental Quality (ADEQ). These are some of the steps we’ll take to comply with Rosemont’s permitting requirements.
  • Rosemont will use a wide range of innovative approaches to ensure no dust leaves the site during construction and operation. Processing equipment will feature cartridge-style dust collectors. Conveyors will be covered and water sprays situated along the conveyors will further minimize dust emissions.
  • Road watering and road binders will be used as required to cut down on dust generated by mine traffic.
  • Rosemont will use natural gas-powered buses to transport employees to and from the mine site, which will help reduce emissions and traffic along State Route 83, the operation’s primary access road.
  • In addition, Rosemont’s dry-stack (filtered) tailings facility will be designed to minimize dust generation, producing far less dust than a conventional tailings storage facility.
  • All haul trucks, and other equipment as available, will be equipped with environmentally efficient Tier 4 engines. Tier 4 diesel engines have the highest EPA emissions standards for off-highway vehicles, delivering a 90% reduction in particulate matter and 50% reduction in nitrogen oxide emissions.

Reclamation – We Believe in Returning a Site Back to Nature, as Soon as Possible

Rosemont’s design philosophy is “begin with the end in mind.” Reclamation on site will begin early in the project and continue throughout the mine’s operating life. Outer slopes, created by earth and rock placement, will be graded, topped with soil and seeded with native grasses and other plants. Reclamation in this manner will not only allow Rosemont to return the site to its natural state as early and efficiently as possible; it will also allow the operation, together with the US Forest Service, to monitor and adjust reclamation practices as needed to ensure success. Key hallmarks of Rosemont’s reclamation program will include:

  • Parts of the site will be left in their natural state. As we reclaim the site, we will compare our reclamation efforts against these untouched areas, which will tell us how well we’re implementing effective reclamation.
  • Ecologists from the University of Arizona have helped identify the seed mix and reclamation practices that will be used to reclaim disturbed areas. The university developed and monitored test plots on site to make sure we get the reclamation right.
  • Invasive plant species, including those that occur naturally, can crowd out native species. On the Rosemont site, these species will be monitored and managed.
  • Slopes, banks and similar landforms will be designed and constructed to minimize erosion and allow for the use of agricultural or other seeding equipment.
  • Stormwater controls will also be constructed on the outer slopes to prevent erosion and direct run-off.
  • Rosemont will set aside funds to guarantee that reclamation and closure activities occur as promised. These funds will be reviewed and updated every three years, and they are in addition to the financial assurance required by state regulators to make sites safe and stable on private lands.


Conservation at Sonoita Creek Ranch

Keeping Dark Skies Dark

Arizona has long been a favourite spot for amateur and professional astronomers. To balance local interest in astronomy while ensuring employee safety, Rosemont will implement a technologically advanced lighting system.

  • Our lighting plan was developed in consultation with an International Dark Sky Association board member and includes filtered LED fixtures, colour rendering to avoid blue-spectrum lights, and shielding/beam control on non-fixed lights to reduce direct uplight.
  • During operations, light emissions will be monitored by Western Research Companies, an organization dedicated to understanding the effects of maintaining dark skies on astronomy and the environment.
  • Rosemont will also provide $218,000 to establish the Smithsonian Institution sky brightness monitoring system at the Fred Lawrence Whipple Observatory on Mount Hopkins and an additional $100,000 per year for the life of the monitoring plan.

Solar Energy Proving Ground

Rosemont has partnered with the University of Arizona’s Research Institute for Solar Energy and awarded five $100,000 grants to renewable energy companies to install solar systems for testing at Rosemont’s Hidden Valley site. The output of each system is being measured to provide information on the efficiency and cost-effectiveness of the systems. Testing and energy production at this solar test site will continue throughout Rosemont’s operating life and be used to offset power consumption at the project’s administration building.