Silver-lead veins may or may not contain minor amounts of sphalerite. Silver-copper veins can also contain minor chalcopyrite, pyrite, and galena as well as trace amounts of other sulfosalts.

The Coeur Mine mineralization generally resembles that of the Galena Mine, in containing a complex vein set controlled largely by the pattern of faults, and the rheology of the Revett quartzitic and argillitic units. Mineralization at Coeur is entirely in tetrahedrite-dominated veins, with no galena-dominated veins.

The tetrahedrite of the Coeur Mine has a lower silver:copper ratio than that in the Galena Mine, about 20 ounces of silver per percent of copper.

The primary mining method at the Coeur mine is conventional cut and fill stopes.

The Coeur mine and shaft is currently on care and maintenance. The Coeur shaft is used for ventilation purposes and provides an alternative means of egress.

The Coeur shaft is a three-compartment shaft, 4,100 feet deep, which is used for exhaust ventilation and when needed for hoisting of silver-lead ore from the Galena Mine and silvercopper ore from the Coeur Mine. The two mines are connected on the Coeur 3400/Galena 3700 Level.

The 450 tonne-per-day capacity Coeur mill is currently on care-and-maintenance since April 2016.

The majority of the mine production over the past few years has been silver-copper ores. This ore is treated in the Galena mill to produce a copper concentrate. Silver-lead ores are also produced, which are currently being treated in the Coeur mill.

The mill flow sheet for the Coeur mill is similar to the Galena mill.

The Galena processing plant follows a conventional flowsheet:

* Crushing and Screening
* Grinding and Cycloning
* Flotation Concentration
* Concentrate Dewatering
* Tailings Pumping for Sand Fill
* Tailings Pumping for Osburn Tailings Storage Facility

Ore from the mine is hauled in 5-ton cars and directly tipped into a 400-ton coarse ore bin located adjacent to the plant. A Pioneer pan feeder feeds material to a 2-foot by 3-foot Kue Ken jaw crusher. The secondary crushing circuit consists of a 3 foot standard cone crusher in closed circuit with a 4-foot by 12-foot vibrating single deck horizontal screen. Minus 5/8” product is conveyed to a 300-ton fine ore bin.

Ore is fed to a 9-foot by 12-foot ball mill, after passing over a weightometer. Grab samples are taken from the conveyor to determine daily moisture content. Ball mill discharge passes over a 3-foot by 6-foot vibrating screen prior to cyclone classification. Cyclone underflow returns to the ball mill while overflow goes to a bank of four 100 cubic foot Denver flotation cells for rougher flotation.

Rougher tails continue to a scavenger circuit of four 100 cubic foot Denver flotation cells. Scavenger tails go to either the tailings facility or are used for underground backfill. Scavenger concentrate is returned to the rougher bank.

Rougher concentrate is cleaned in two stages using Denver Sub-A flotation cells. Cleaner concentrate is sampled and pumped to a 10 foot high by 20 foot diameter concentrate thickener. Thickened concentrate is pumped to parallel drum filters. Filter cake is regularly loaded onto trucks for shipment to the smelter.