A striking feature of the Galena Complex mineralization is that two entirely distinct types of utterly different ore mineralogy occur within the mineralized envelope. These are: 1) silver-copper veins and disseminations, dominated by tetrahedrite, and 2) silver-lead veins and disseminations, dominated by galena.

Mineralization at the Galena Mine is typified by structurally controlled veins that can extend for a few thousand feet of depth and hundreds of feet of strike. The general strike is N 50 W, with steep dips to the south, but there are many local variations. Due to the complex threedimensional arrangement of the numerous veins, which include NW, NE and N-S trends, a two-dimensional graphic presentation is difficult.

The veins principally contain silver, lead, copper and zinc in relatively simple mineralogy. Silver is the primary economic metal at the Galena Mine. Historically, the “silver-copper” veins, containing argentiferous tetrahedrite have been the focus of production at the Galena. The silver-copper ratio averages 30 to 35 ounces per percent copper. Typically, the silver-lead ratio of silver-lead ore at the Galena Mine is about 0.9 opt silver per 1.0 percent of lead.

The mineralized veins at the Galena Mine occur along four major fracture systems and three major faults (South Argentine, Argentine, and Polaris). The veins generally strike east-west to northeast-southwest, and dip vertically to steeply to the south. Thickness ranges from a few inches to over fifteen feet.

The vein fillings are a gangue of siderite with variable amounts of pyrite and quartz as blebs and stringers. The ore bearing sulfides are predominately galena, tetrahedrite and chalcopyrite, with pyrite.

Wall rocks for the vein mineralization are not significantly mineralized except, where cut by narrow unnamed veins or stringers.

The Silver Vein at the Galena Mine is one of the widest and most productive veins in the history of the mine. The vein cuts through quartzites and siltites of the Revett Formation for over 3,600 vertical feet with an average strike length of 1,000 feet. It can be as narrow as 1.0 foot and as wide as 15.0 feet but typically averages about 4 feet wide. The Silver Vein consists of massive siderite with pods of quartz and chalcopyrite and scattered blebs and stringers of tetrahedrite.

The 185 Vein in the Galena Mine strikes east-west within a hard quartzite unit and consists of zones strongly enriched in silver bearing galena. Common accessory minerals are pyrite, ankerite, barite, and quartz. Only trace amounts of tetrahedrite are typically found within the vein.

The fault-bounded veins are found within three major structures that cross through the Galena Mine. These veins include the 31, 72, 133, and 164 Veins hosted by the Polaris fault, the 117 Vein hosted by the South Argentine fault, and the 123 Vein hosted by the Argentine fault. The wall rocks encompassing these fault-controlled “veins” vary throughout the mine from soft siltite argillites to very hard quartzite.

The Polaris fault is a major fault and strikes west-northwest to east-southeast and cuts through the middle of the Galena Mine, and south of the Coeur Mine. The Argentine and South Argentine faults are smaller east-west striking faults that lie north of the Polaris fault.

The 72 Vein is a silver-enriched narrow vein bounded by the Polaris fault. It strikes at approximately N 75 degrees W and dips to the SW at -70 degrees. The genesis of the 72 Vein ore body is hypothesized to be the result of left lateral oblique movement along the Polaris fault that produced dilation zones in brittle quartzite units creating openings for silver concentrations from metal rich metamorphic fluids. The ore-bearing quartzites are bounded by more ductile siltite units that according to drill data cut off the mineralization along strike and up-dip. At the current drill limits the 72 Vein exhibits an ore grade strike length of 1,200 feet and a down-dip length of 900 feet. However, drill data between the 5500 and 5800 elevations reveals that the 72 Vein ore body is open down dip, showing increasing Ag grades within a thickening quartzite package.

Mineralogically the 72 Vein is composed primarily of massive siderite veins that contain variable amounts of tetrahedrite, chalcopyrite, pyrite, and trace galena. These siderite veins and stringers are commonly found as brecciated angular to sub-rounded clasts set in a fault gouge matrix. Tetrahedrite is not always visible and can appear as black powder.

The 117 Vein is hosted by the South Argentine fault. It is a strong siderite vein with small tetrahedrite blebs and parallel stringers. Hard quartzite in the hanging wall and siltite and argillite in the footwall bound the vein. Silver bearing tetrahedrite mineralization appears to rake flatly up dip to the northwest at about 40 degrees. The vein varies in width from 2 to 12 feet. In certain areas of the mine the vein will pinch out and only a black mineralized fault is present.

The 123 Vein is a narrow siderite vein with small parallel tetrahedrite stringers. The vein is found within the Argentine fault, north of the Polaris fault and the 117 Vein. The hanging wall of the 123 Vein is a barren soft argillite while the footwall is a mineralized siltite-quartzite. The vein averages 2 to 4 feet wide and during mining the soft argillites in the hanging wall are found to be not competent which can cause dilution.

The Coeur Mine, northwest of the Galena Mine, contains a Mineral Resource which is dominantly within the 425 Vein, the 400 Vein and the 356 Vein with Measured, Indicated and Inferred Resources on 12 other veins. The Coeur Mine had been idle since 1997 until Americas Silver rehabilitated the mine and resumed production in the second half of 2012 in the 425 Vein. Production ceased in 2014 due to low prices and the focus changed to silverlead mineralization.

The Coeur Mine mineralization generally resembles the Galena Mine, in containing a complex vein set controlled largely by the pattern of faults, and the geology of the Revett quarzitic and argillitic units. Pre-1997 workings at Coeur attained a depth of 4,225 feet below surface (3900 Level), and were mostly in the 356, 400, and 483 Veins.

It has been noted that the tetrahedrite of the Coeur Mine has a lower silver/copper ratio than that in the Galena Mine, about 15-20 ounces of silver per percent of copper.

The disseminated mineralization consists of small stringers and disseminations of galena in wall rock sediments. This style of mineralization is locally termed "blue rock".

Disseminated galena mineralization mainly occurs in thicker bedded, relatively more siliceous stratigraphic intervals. The disseminated mineralization ranges from narrow, weak zones less than a foot thick, to strongly mineralized zones which are several tens of feet thick. Disseminations vary from mottling and streaking to completely pervasive. Disseminated galena commonly follows lamination, where present, in siliceous rock. Galena grains in “blue rock” are usually quite fine, but variable. Blebs and pods of galena up to about ½ inch comprise a minor part of the disseminated mineralization. Pyrite is often present in minor amounts.

Disseminated mineralization is usually strong (greater than 6% Pb) around major lead veins. Major lead veins are mainly on the southwest (stratigraphically lower), side of the Caladay Zone. These veins, typically about 2 feet thick, may carry more than 40% Pb and relatively high pyrite (greater than 20%). The stronger intervals of “blue rock” in general contain galena-bearing stringers and pods. Stringers up to about 0.2 foot or 0.3 foot in width average roughly one per two to four feet in the strongest “blue rock”. These stringers consist of quartz, galena, pyrite, and siderite. Very high-grade stringers carrying more than 40% Pb are present.

The #3 Shaft is currently the primary mine access shaft and has been developed to a depth of 5,850 feet. It is a three-compartment shaft, equipped with a 1,750 hp Nordberg, 12 ft. dia. double drum hoist, which raises 8-ton skips in balance. Lateral development, off of the #3 and Galena shafts, includes work on 12 levels. For several years prior to 2010, the #3 Shaft hoisted all of the silver-copper ore produced in the Galena Mine, as well as all men and materials entering the mine. The #3 hoist drive and control system were upgraded in April 2012.

The Galena Shaft was repaired and updated in 2009-2012, and was placed in service again in early 2011. The Galena Shaft currently serves as the primary shaft for moving personnel, equipment and supplies into and out of the mine. It is 5,540 feet deep, with a threecompartment timber shaft equipped with a 900 hp Nordberg hoist. Although additional work in the Galena shaft is still on-going for pocket installations, the completed repairs have allowed hoisting in this shaft to resume between the 5200 Level and surface.

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.

Lateral development from the shafts is generally spaced about 300 feet apart, vertically. Level development historically has been conducted by track drifting and rail haulage. Since 1999, the Galena Mine has developed seven areas with rubber-tired diesel equipment. Lateral track drifts extend for thousands of feet out from the shafts in an east-west direction. The levels provide access to over 100 veins that are currently producing, or have produced in the past.

Currently, most ore production is coming from mechanized cut and fill stopes. However, over the years, the Galena Mine has utilized three mining methods to extract ore from underground veins. These are:

• Conventional “overhand” cut and fill stoping, using hydraulically-placed mill tailings for backfill. Typically, the backfill for overhand stoping does not include cement for added strength.

• Mechanized “overhand” cut and fill stoping, using hydraulically-placed mill tailings for backfill. Typically, the backfill for overhand stoping does not include cement for added strength.

• Mechanized “underhand” cut and fill stoping, using hydraulically-placed mill tailings for backfill. Typically, the backfill for overhand stoping includes cement for added strength.

In the conventional overhand stoping, the veins are accessed by crosscuts developed from drifts that are driven along the vein structure. Final development of the vein is accomplished by driving vertical, timbered, three compartment raises along the vein from one level to the level above. A typical stope extends 100 to 200 feet along the vein, on either side of the raise. A typical cut, 9 feet in height, over the length of the stope, is mined, using jackleg drills and pneumatic/electric slushers, which move the broken ore to the ore passes at the stope access raise. After all of the broken ore has been removed from the stope, the void is filled with slurry of mill tailings. After the sand fill process is complete, the cut above is mined in the same sequence. Some advantages to this method are its ability to extract narrow (less than 5 feet wide structures) without causing excessive dilution, and that all development subsequent to the initial crosscutting is in ore material.

In mechanized overhand cut and fill stoping, all drilling, and ore loading is performed with rubber-tired, diesel equipment. Drilling utilizes one boom electric-hydraulic jumbos, and ore loading is performed using 1-cubic yard and 2.5-cubic yard LHDs. Access to these veins is in the same manner as in the conventional cut and fill stopes, via track haulage development. Final development of the stopes is accomplished by driving a 10 foot by 10 foot (+15%) inclined ramp in the hanging wall of the structure. The vein is then accessed from the main ramp by running temporary attack ramps. A typical stope extends 200 to 400 feet along the vein on either side of the main ramp/stope intersection. A cut of ore, 10 feet in height, is mined over the entire length of the stope with the trackless equipment. After muck removal, the stope is backfilled as in the conventional stopes, and the sequence proceeds upward.

In mechanized underhand cut and fill stoping, crosscuts and drifts also initially access the veins. Final development of the vein is accomplished by driving a 10 by 10-foot (-15%) declined main ramp, approximately 100 feet in the hanging-wall of the structure, and then finally accessing the vein by running temporary attack ramps from the main decline to the vein. A typical stope extends 200 to 400 feet along the vein on either side of the attack ramp entry point to the stope. A cut of ore, 10 feet in height, is mined over the length of the stope with the use of electric jumbo drills and diesel LHDs. After all the broken ore is removed from the stope, the void is filled with a slurry of mill tailings, cement and water. After these cemented tailings harden, typically 7 days, the cut directly below is mined in the same sequence. The two main advantages with this method are its ability to extract ore from levels below the current shaft bottom (avoiding some capital development), and its proven ability to minimize hazards associated with rock bursting.

The Galena Complex consists of two processing plants, Galena and Coeur. The Coeur plant has been on care and maintenance since April 2016. 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 

The Galena mill has an installed milling capacity of 630 tonnes-per day but operates below capacity.  The 450 tonne-per-day capacity Coeur mill is currently on care-and-maintenance.

Mine production over the past few years has been from both silver-copper and silver-lead ores, with recent production coming mostly from silver-lead ores. Currently, ore is treated in the Galena plant to produce a lead concentrate.

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.