Talon Metals Nickel Sulfide Proposed Mine, Kettle River Watershed
Wild Rivers Conservancy acknowledges that the world must address climate change, with the understanding that new sources of raw materials such as nickel and copper are needed.
However, any mining venture in an area of the St. Croix Watershed that is primarily composed of wetland/peat/lake surface features must require strong measures to prevent irreparable harm to the surface or groundwater. Nickel Sulfide mining is incompatible with this region and ecology.
This position document addresses an emerging threat to the St Croix watershed due to the ongoing permit process by Talon Metals for a Nickel Sulfide mine to be located at Tamarack, MN. The initial permit is for a small portion of the identified ore body, but, as is typical with mining operations, once the initial permit is exhausted, Talon has the ability to expand operations without filing a new permit. The initial permit location is located within the Mississippi watershed, but the mining operations will extend into the St Croix watershed as the mine expands to cover the entire ore deposit.
Talon has submitted an Environmental Assessment Worksheet (6/2023) covering the proposed underground mining project. This will culminate in a Scoping Document which will have a 30 day comment period and later an Environmental Impact Statement with a further 30 day comment period, both prior to possible approval by the governing bodies.
Nickel Sulfide mining poses a significant threat to aquifers and surface waters. In the ore body, the metal atoms are bound to the sulfide rock. Metal sulfide ore is stable when underground prior to mining. The problem occurs when the ore deposit is broken into smaller pieces causing increased surface area which enables new chemistry to occur. In the presence of oxygen and water, sulfides reduce to sulfuric acid, which can then leach heavy metals from the ores. Water with acid and dissolved heavy metals can then enter the aquifers and surface water. Acid and heavy metals are detrimental to fish and aquatic life. Acidification and heavy metal poisoning are common by-products of Nickel Sulfide mining, even under the best of conditions.
The Talon mine is located in an especially troublesome area. Tamarack, MN is covered with wetlands, peat bogs, and lakes - water features account for approximately 90% of the area where the ore body is located. The surface water is in direct contact with aquifers that deliver clean water to much of the region.
Mining can also damage surface waters due to the need to keep the mine dry. Fissures in the rock cause surface water to drain into the mine. Talon has estimated that for the initial mine (447 acres or 0.7 square miles), it will be necessary to pump 2.3 million gallons of water per day. An example of the impact from mine pumping on surface water features has been observed at the existing Eagle Mine in the Upper Peninsula of Michigan, which requires only ~5% of the mine pumping volume that is projected for Tamarack. The Eagle mine is located in an area that has less surface water than Tamarack and has required much less mine pumping, but the lakes and wetlands near the mine have decreased in water height by approximately 1.7 feet.
The ore deposit is much larger than the original 447 acres that is covered by the current permitting process at Tamarack. Talon has been mapping the viable portions of the deposit, and it is currently demonstrated to be approximately 11 miles long - spanning from Tamarack to the South and East. More than half of the high value ore deposit is located in an area that is in the St Croix watershed but is not covered in the initial mine permit.
If the mine proceeds, it is expected that the result will be:
- Water pollution to aquifers and surface water via acidification and heavy metal contamination
- Significant negative impacts on fisheries and other aquatic life
- Impairment of Wild Rice harvest affecting multiple tribes/treaties
- Regional lowering of the water table resulting in decreased lake elevations and drying of swamp and peat lands