Mod PRO: We are listening

Mod PRO: We are listening

Published on October 5, 2019


When we submitted our Plan of Restoration and Operations (PRO) for the Stibnite Gold Project to the U.S. Forest Service in 2016, we submitted what we considered the best plan possible based on information available at the time. We spent tens of millions of dollars and invested thousands of manhours studying the site to develop our plan. However, our work did not stop once we submitted our plan.

In fact, since we submitted the PRO, we’ve developed a deeper understanding of the area. This knowledge allowed us to build upon and improve certain areas of our plan, so, in May, we submitted a modified version of the PRO (known to us as the Mod PRO), to the U.S. Forest Service.

As we worked through the permitting process, we had more opportunities to speak with community members regarding the plan set out in the PRO. We listened to feedback, concerns and suggestions on how we could reduce our impacts on the environment and design an even better project. We took this feedback and used the more detailed feasibility analysis we’d collected at the site to write the Mod PRO. Our team is proud of the changes we’ve made to our original plan. They are a direct reflection of community input and improvements made possible by the scientific process of permitting.

When the U.S. Forest Service releases a draft Environmental Impact Statement (dEIS) on the Stibnite Gold Project, the community will have a chance to weigh in on the changes we’ve made. However, the U.S. Forest Service is reviewing the updates we’ve made and it is possible we and they will make additional improvements before the comment period. We anticipate the Mod PRO will be included as an alternative, along with other alternatives, to our original plan in the dEIS.


The Mod PRO encompasses incremental improvements to many areas of our project site. While this blog does not include a look at every update we’ve made, we wanted to share some of the highlights with you.


Throughout the Stibnite Gold Project, we will produce a lot of development rock – rock we pull from the ground that does not contain any economically recoverable minerals. We estimate we will need to safely store approximately 350 million tons of development rock on our site. In the Mod PRO, we’ve made updates to how we store development rock in order to reduce our impacts to salmon habitat, reduced the distance we are moving rock on site and preserve more areas in the valley for wetland restoration.

We were able to eliminate the need for the West End development rock storage facility by making adjustments to the timing and sequence of mining. By mining the Yellow Pine Pit first and then moving to the West End Pit, instead of trying to mine these areas concurrently, we can reduce our surface impacts in this area and help protect water quality in West End Creek. Another positive impact from this decision is it we will be able to backfill Midnight Pit entirely. Originally, in the PRO, Midnight Pit would have eventually become a pit lake.

As we already know, based on current conditions at site, the rocks at site are generally mineralized and can cause metals to leach into the surface and groundwater. So, after further study, we plan on adding covers to our development rock storage areas to minimize the potential for metal leaching in the future by substantially reducing the ability for water to interact with the development rock.


Water quality at the historical Stibnite Mining District is already degraded both due to mining activity over the last century and because the area is highly mineralized. Today, there are high levels of sediment in the surface water, along with elevated levels of arsenic and antimony. The original PRO we submitted included many measures to improve ground and surface water quality. However, the Mod PRO has taken our plans a step further, allowing us to not only make more improvements to water quality but also help to reduce water temperature and improve aquatic habitat.

Some of our proposed changes are focused on Hennessy Creek. This creek has been diverted for past mining operations and part of it is still buried today. During low flow, it seeps through legacy rock dumps before entering the East Fork of the South Fork of the Salmon River. To prevent this from happening, we now propose creating a temporary water diversion channel that will reroute the creek 800 feet above the Yellow Pine Pit and, using gravity, connect it to Fiddle Creek. Rerouting the creek will prevent it from flowing through the Bradly dumps, an old mine rock storage facility. Once mining at the Yellow Pine Pit is complete, the temporary water diversion would be closed and Hennessy Creek would be able to flow into the restored East Fork of the South Fork of the Salmon River.

Our plans have always included reconstructing the Meadow Creek stream channel to create more sustainable habitat for fish. According to the PRO, we will install a liner under Meadow Creek to minimize the stream losing any water as it travels past the Hangar Flats Pit. This will allow Meadow Creek to be a fully functional stream channel that will provide valuable spawning and rearing habitat during mine operations. However, in the Mod PRO, we now plan to extend the liner more than 1,000 feet past the old pit in order to reduce potential water loss and maintain consistent stream flows.


The issue of public access to the project site is another example of how we listened to and worked with our community partners. During the public scoping process, we consistently heard maintaining access through our site to Thunder Mountain Road for recreationalists during construction and operations was key. Originally, we did not plan to have a public access through the site because of safety concerns. However, we realized this was an important issue for the community, and our team worked together to identify a potential solution that still prioritized safety. As a result, in the Mod PRO we’ve proposed maintaining access through the site by routing traffic on a road through or near the Yellow Pine Pit.

If you have questions about our plan on the Mod PRO, we encourage you to reach out to us. You can stop by our monthly office hours in Donnelly on the first Friday of the month from 11 a.m. to 3 p.m. or email us at [email protected].

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