Galena where is it mined

It strikes at approximately N 75 degrees W and dips to the SW at 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, feet and a down-dip length of feet. However, drill data between the and 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 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 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 Vein. The hanging wall of the 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 had been idle since until Americas Silver rehabilitated the mine and resumed production in the second half of in the Vein. Production ceased in 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 workings at Coeur attained a depth of 4, feet below surface Level , and were mostly in the , , and Veins.

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. Pyrite is often present in minor amounts. Major lead veins are mainly on the southwest stratigraphically lower , side of the Caladay Zone. Stringers up to about 0. These stringers consist of quartz, galena, pyrite, and siderite. The Galena Complex property covers 8, acres over an approximate area of 9 miles long east-west and 2 to 3 miles wide north-south.

The Complex contains four shafts, all connected by deep underground workings. The Galena and 3 shafts are near the center of the property, while the Coeur shaft is approximately 1. The Caladay shaft and workings are currently used as ventilation exhaust for the Galena workings.

The current mining methods used at the Galena Complex are conventional cut and fill and mechanized cut and fill. Mechanized cut and fill is done using both overhand and underhand methods. In the case of the overhand method, sand fill is used as backfill, typically without the addition of cement.

For the underhand method, cement is typically added to the sand fill in order to provide the required strength to work underneath the placed backfill. Ore is hauled to either the Galena or 3 shafts via tracked locomotives and rail cars. Waste associated with primary and secondary development is typically kept underground and placed as fill in old headings and open stopes.

As needed, it can be hauled to the shaft, skipped to surface and placed on the existing surface waste rock storage facility. Ore is currently skipped to surface from several levels of the mine using either the 3 hoist. 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. Ore from the mine is hauled in 5-ton cars and directly tipped into a 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. Galena is a lead sulfide mineral with a chemical composition of PbS. It is the world's primary ore of lead and is mined from a large number of deposits in many countries.

It is found in igneous and metamorphic rocks in medium- to low-temperature hydrothermal veins. In sedimentary rocks it occurs as veins, breccia cements, isolated grains, and as replacements of limestone and dolostone. Galena is very easy to identify. Freshly broken pieces exhibit perfect cleavage in three directions that intersect at 90 degrees. It has a distinct silver color and a bright metallic luster. Galena tarnishes to a dull gray.

Because lead is a primary element in galena, the mineral has a high specific gravity 7. Galena is soft with a Mohs hardness of 2. Crystals are common and they usually are cubes, octahedrons, or modifications. Structure of galena: Galena has a chemical composition of PbS. That means it contains an equal number of lead and sulfide ions. The ions are arranged in a cubic pattern that repeats in all directions. This structure is what causes crystals of galena to have a cubic form and causes galena to break in three directions at right angles.

Argentiferous galena: Argentiferous galena from Coeur d'Alene, Idaho. Argentiferous galena has a silver content that is often high enough for the galena to be mined as an ore of silver. Some galena mines receive more revenue from their silver than from their lead production.

The typical specimen of galena is about However, some specimens of galena contain up to a few percent silver by weight. They are called "argentiferous galena" because of their silver content. In these specimens, silver can substitute for lead in the atomic structure of the galena, or it can occur in tiny grains of silver minerals included in the galena. Silver within the galena disrupts the crystal structure, which often causes the galena to have curved cleavage faces. This tiny bit of knowledge can be a powerful prospecting tool.

In addition to silver, galena can contain minor amounts of antimony, arsenic, bismuth, cadmium, copper , and zinc. Sometimes selenium substitutes for sulfur in galena. Cleavage fragments of galena: One of the most diagnostic properties of galena is its ability to break by cleavage in three directions that intersect at right angles.

This forms cleavage fragments that are cubic and rectangular in shape. This photo shows pieces of crushed galena that clearly exhibit the right angle cleavage.

This characteristic cleavage is caused by the mineral's cubic internal structure as shown above. Galena value: Some mines produce more revenue from the silver content of their galena than from the lead content. The small amount of silver has a huge impact on revenue because at the prices assumed, silver is times more valuable than an equal weight of lead.

It is easy to understand why mining companies get excited by argentiferous galena! Even though galena is the ore being removed and lead makes up the bulk of the product, these mines are often called "silver mines. Latest Updates. Regional Exploration.

Abra and Jillawarra Abra, and possible extensions to Abra, is the main focus of Galena, but the regional tenement package has excellent potential for Copper-Gold deposits as well as further lead-zinc-silver deposits.

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