Environmental Considerations

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Cumo Project - Access


Cumo Project - Old Tailings

Contaminated Tailings in Grimes Creek, 15 miles down stream from CUMO Project

Cumo Project - Old Tailings

Close up of Contaminated Tailings with Grimes Creek meandering through the flat valley, 17 miles down stream from CUMO. Very difficult for any sediment or toxic spills to travel through this area.
Given the staggering economics and the resulting benefits to the local community of a project like CUMO, the potential impacts to the environment and methods of mitigating them require discussion.

It is Mosquito's professional opinion that a potential mine at CUMO could be designed and built in such a manner to keep environmental impact to a minimum and to mitigate any potential impacts through best management practices to ensure state of the art environmental protection and stewardship. Using a proven and highly successful model developed by the nearby Thompson Creek Mine, Mosquito intends to use an interagency task force to establish full co-operation with state and federal regulatory agencies. This model and the resulting work have been recognized for its excellence by many agencies and environmental groups. In addition, through a series on-going consultation processes, local residents and various qualified environmental groups will be expected to participate and contribute to the development of the project, thereby ensuring the success of the project.

CUMO would be an open pit MOLYBDENUM-COPPER mine producing two separate metal concentrates; Molybdenum and Copper. These would be shipped by truck to smelter and roasting sites located elsewhere. Only 5 to 6 trucks per day are required to ship the concentrate off site. The milling and processing facilities for such a mine consist of simple flotation - no large amounts of toxic chemicals are used in the process. The operation would use the same process as the nearby Thompson Creek Mine, which has operated in close proximity to the Salmon river (wild scenic river) for many years.

With today's standards, modern mines have an excellent record of environmental responsibility and there are numerous examples of fully reclaimed mine sites.

The main environmental considerations for Open Pit mines such as CUMO are: water quality, waste dumps, tailings ponds, and transportation corridors.

Water Quality

Probably the biggest issue in the area of CUMO, as far as environmental groups are concerned, is water quality, with the specific concern being the quality of water in the Boise River. CUMO is located over 50 miles from where Mores Creek runs into Lucky Peak Reservoir (created by damming the Boise River). The Lucky peak dam is located approximately 11 miles upstream of Boise.

Due to its location, the CUMO Mine can have no effect on the Boise River. The distances involved are just too great. The fact that the existing contamination in the Grimes Creek Valley has never reached the Boise River in the past hundred years is excellent proof. This contamination has been caused by historic placer and hard rock mining, human habitation, and logging. The following points provide additional support:

1. The CUMO Project is located on Grimes Creek, which flows 32 miles from the CUMO project to its junction with Mores Creek. Over that distance, Grimes creek flows through many miles of flat meandering sections which have been extensively placer-mined over the years. The resulting tailings gravel piles and the flat slope result in a natural filtration system that would prevent any spills or sediment from reaching Mores Creek, and thus the Boise River. If such a spill was to occur the mines on site monitoring team would have ample time to clean up any possible contamination or spills.

2. Within the mine site itself, Grimes Creek itself would be protected by a 500 foot wide riparian zone (3 times larger than legally required), resulting in no changes within this zone.

3. Waste dumps would be located a couple of miles up side valleys, which contain non-fish bearing intermittent creeks. Sediment runoff from the dumps is easily controlled through a series of settling ponds located on each valley below the base of the dumps. This would ensure no sediment or silt occurs in the water discharge as a result of waste dump development.

4. Tailings ponds would be located in similar creek valleys with settling ponds capturing any runoff and recycling of water back to the Mill site.

5. Detailed studies completed to date indicate that waste material is benign, non-acid generating, and is the same material that has been weathering for millions of years, depositing its sediment in Grimes Creek. In fact, due to the presence of old historic mines located downstream from CUMO, some of the water and sediment analyses completed on Grimes creek lower down have significantly higher values than the CUMO waste. More studies will be completed before the mine is even considered for construction.

6. Tailings material tested to date (~ 3/4 ton of material) indicates it is non-acid generating and contains no harmful quantities of toxic elements.

7. Molybdenum is a natural fertilizer. For example, several studies have shown that adding 0.5 to 1 lb of molybdenum to an acre increases crop yields by 30%. CUMO's tailings could be a low-cost natural fertilizer. This will be examined in upcoming studies.

8. All mine waste discharges, settling ponds, and drainage at today's mines are monitored on a regular basis as part of a state-of-the-art environmental management system. This ensures that water quality is protected and in fact, for most modern mines the water quality being discharged is actually better than the quality of water in the existing creeks.

The end result is that a potential mine operation at CUMO would have no detrimental effects on the water quality. In fact, Mosquito suggests that the water quality would actually be improved by the mine development due to the following:

1. Historic gold mine waste dumps would have to be examined and cleaned up. These currently are leaching metals into Grimes Creek.

2. The heavily contaminated areas of the Placer tailings would also have to be cleaned up, especially given the extensive usage of mercury.

3. As a result of the continuous water quality monitoring program, leaking septic fields would be easily identified and cleaned up.

Overall the result is a cleaner quality of water than what exists in the drainage today.


Open Pit During Mining


Same Open pit after reclamation

Open Pit

The open pit is a large hole in the ground, which at the end of mine life is reclaimed either by back filling waste material into the pit or creating a lake. Given the benign nature of the rock that surrounds the CUMO Mine, the open pit when finished, can easily be converted into a recreation area and stocked with a variety of local fish. It should be noted that detailed studies to date completed by independent engineering companies indicate that CUMO does not have the same problem as Thomson Creek with its pit water. Thompson Creek's pyrite content in the rock is several times higher than CUMO resulting in pit waters being acidic and thus requiring special treatment. CUMO with its low pyrite content does not create acid generating rock. If future studies show this to be incorrect then the proven special treatment used at Thompson Creek will be required. The pictures above show an excellent example of the before and after appearance of a reclaimed open pit site.


Reclaimed Waste Dump

Waste dumps

As already mentioned, waste dumps would be located in areas such that any runoff would be controlled through a series of settling ponds. As the mine progresses, ongoing reclamation would be completed, which would result in reclaimed areas with new growth of vegetation and trees. It has been recent experience at several modern mines that these reclaimed areas attract wildlife to the area to feed on the rich new growth. Once the mine is complete, full reclamation of the waste dumps can be completed and after 10 years there will be very little sign of them.


Old Copper Mine Tailings Site during Operation(Nevada)


Same tailings site Reclaimed (7 years after mine closure)



Another Reclaimed Tailings Site Supporting herds of Cattle and Bison.

Tailings Pond

Currently, as a result of an independent metallurgical study on a ¾ ton sample from the main core of the deposit, the tailings created by simple flotation process have been shown to be non-acid generating and contain no harmful toxic elements. As mentioned above, the natural fertilizer capability of Molybdenum makes it ideal for reclamation. As the mine develops, the tailings dam area can be reclaimed. At mine closure, all tailings can be reclaimed in such away as to ensure a healthy population of wildlife. For example, the Figures above show a picture of a reclaimed molybdenum--copper tailings ponds in Nevada and British Columbia. Growth rates are extremely fast, and a healthy population of bison and/or cattle now feed on the vegetations. All sorts of crops are capable of being grown on these reclaimed tailings ponds. As tailings disposal proceeds, water squeezed from the tailings is collected and recycled back for use in the mill. Using proven practices from desert environments, where water is as precious as gold, 95% of the waste water is recycled with the remaining 5% being lost through evaporation. As the tailings solidify and pack, they become stable and thus strengthen against any possible failure. Rainfall and incoming water is controlled and diverted around the pond into the settling ponds where it is recycled back to the mill.

Transportation Corridors

Preliminary examination of the current transportation routes indicate that materials, products and personnel can all be moved along transportation corridors away from major rivers or settlements. With minor upgrades, existing roads can be used. Major county-maintained roads exist in the area of Centerville (see figures above). Transportation in and out of the area is accomplished by connecting to State Highway 55 (an existing major transportation hub), located to the west. Connecting to the 4-lane highway to the south, Horseshoe Bend would avoid the Payette river and the town of Horseshoe Bend. The corridor is an existing transportation route for the small number of people that live in the area.

A secondary access route connects Centerville with Hwy 21 and then on to Boise. This route is not preferred, as it winds through narrow canyons and involves transportation along the Boise river corridor. Even though Hwy 21 is a major transportation hub, the Horseshoe Bend route is significantly better. As with all developments, a transportation plan will form part of the feasibility study. The plan would address concerns of local residents, especially avoiding existing school bus routes and any environmentally sensitive areas.

Overall, with proper planning and modern state-of-the-art environmental protection and stewardship, the CUMO project should prove to be a net benefit to the environment, by cleaning up existing contamination and pollution, discharging cleaner water, and possibly supplying a natural fertilizer that could replace existing non-environmentally friendly fertilizers. Funding for the ongoing monitoring and reclamation work is provided by the Mine and also guaranteed by a bond that is in place prior to the construction of the mine. No development can occur on public land without having a suitable bond in place to cover reclamation costs.

Finally, the molybdenum product that the CUMO project will produce is used in numerous applications to improve the environment in which we live. Molybdenum steel is used in oil and gas pipelines, oil tankers, nuclear reactor shielding, desalination plants for fresh water and wind turbine blades. The strength of molybdenum-bearing steels is being used to help prevent dangerous and toxic spills worldwide and as a catalyst molybdenum cleans the diesel fuel we use everyday.