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What is Non Acid Generating rock (NAG)?

Non Acid Generating rock (NAG)  is rock that in surface weathering/oxidizing conditions produces no acid. Our current test results show that most of the excess rock resulting from mining at Black Butte is non-acid generating. This is good news as this rock contains sufficient carbonate minerals to neutralize any potential acid generation from mineralized material.

What elements of concern are in the rock that we will need to treat?

Based on extensive testing of the surface and groundwater of the area, which naturally leach metals from the surrounding rock, and the results of humidity cell tests on waste rock and cemented tailings, the most persistent elements exceeding groundwater and surface water standards are arsenic (As), selenium (Se), thallium (Tl), and strontium (Sr). Other elements, including copper (Cu), lead (Pb), nickel (Ni), mercury (Hg), cadmium (Cd), and zinc (Zn), could be of concern if waste rock were not properly managed. Fortunately, responsible management minimizes the amount of leaching of these elements into site water during the operation, and reverse osmosis water treatment removes all of them.

How will water be protected?

We take protecting all the water resources seriously. Tintina’s professionals chose the tunnel entry location specifically because it is almost 200 feet above the water level. In order to keep water from leaving the mine and mixing with creek water, all planned openings or entry points to the mine (including air ventilation and escape routes) are located far above the water table. Tintina’s professionals chose the tunnel entry location specifically because it is almost 200 feet above the water level.

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What elements of concern are in the rock that we will need to treat?

Based on extensive testing of the surface and groundwater of the area, which naturally leach metals from the surrounding rock, and the results of humidity cell tests on waste rock and cemented tailings, the most persistent elements exceeding groundwater and surface water standards are arsenic (As), selenium (Se), thallium (Tl), and strontium (Sr). Other elements, including copper (Cu), lead (Pb), nickel (Ni), mercury (Hg), cadmium (Cd), and zinc (Zn), could be of concern if waste rock were not properly managed. Fortunately, responsible management minimizes the amount of leaching of these elements into site water during the operation, and reverse osmosis water treatment removes all of them.

What water tributaries are in the immediate area?

The principal stream near the mine is Sheep Creek—to protect Sheep Creek, the mill facility and cemented tailings impoundment are one mile south of Sheep Creek. A tiny streamlet, Raccoon Creek, lies between the facility and Sheep Creek. A branch of Little Sheep Creek lies east of the surface facility but in a different sub-tributary drainage. Our top priority is protecting all water sources.

How far is the Smith River from the Project?

The Smith River is 19 stream miles from the confluence of Sheep Creek and the Smith River. To protect all water resources, the cemented tailings facility will be located one mile off Sheep Creek, and all facilities including the tunnel opening will be located out of the valley, in a saddle of Sawmill Hill. Tintina purposely chose this distant location to ensure a superior job of environmental management for the mine site and for protection of all local waterways.

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Do we monitor water and why?

Yes, water monitoring is important and accomplishes two things. First, it allows us to establish a baseline understanding of water quality and quantity under conditions prior to mining. Second, after mining is underway, monitoring allows us to detect any changes in water quality or quantity. Montana has very stringent water quality laws that protect the environment by stipulating that if we are not meeting all standards, we will be shut down immediately until resolution that protects the environment is completed.

How will tailings be managed on surface?

To protect our valuable water resources and the environment, Tintina has designed a Cemented Tailings Facility (CTF) that improves on established practices by allowing for a solid, dust free facility. After filtering and squeezing out most of the water, tailings mixed with cement will be permanently stored in a 100 mil High Density Polyethylene (HDPE) double lined facility in a non-flowable state. There will be a pump back system placed in the bottom of the facility so that the small amount of water squeezed from the tailings as it sets up as well as any precipitation occurring on the facility is pumped into a double lined process water pond.

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What method of mining will be used underground?

The mining method contemplated in the PEA is called both “cut and fill” or “drift and fill”, which means that part of the deposit will be mined out (cut) and paste backfill non-mineralized rock will be placed in that opening (fill). This greatly reduces the amount of tailings that are stored at surface level as approximately half of the tailings will be placed back underground as paste backfill. Tintina is evaluating various scenarios to minimize the amount of tailings to be stored at surface.

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What are mine tailings?

Once the mined rock is taken from a mine, it is ground to a fine powder in a mill located onsite. There, the copper mineral (chalcopyrite) is separated from the remainder of the rock into a concentrate for shipping. The remaining rock is called tailings.