Silver is the whitest of all metals. This property, and its high reflectivity, was responsible for its Latin name argentum (white and shining), from which the chemical symbol for silver, Ag, is derived. Because it does not readily oxidize, silver can be found in the native state - in metallic form rather than as a compound - and can therefore be assumed to be one of the first metals discovered. It has been found in tombs dating from 4000 BC.
Silver reflects 95 per cent of the light that strikes it, making it the most lustrous (shiny) of the metals. Silver conducts heat and electricity better than any other metal does. It is second only to gold in ductility (the ability to be drawn out into fine wires) and malleability (the ability to be hammered into various shapes). Silver, like gold, does not react chemically with most substances. However, the presence of sulfur compounds causes silver to develop a black or gray coating of silver sulfide called tarnish. Because polluted air contains these compounds, silver tarnishing is a greater problem today than in the past.
The chief silver-mining areas of Canada are located in New Brunswick and Ontario. Silver occurs in deposits of native metal and as silver ores. Native silver mines provide only a small amount of the world's silver. Silver often occurs along with such metals as copper, gold, lead and zinc. Miners obtain about 80 per cent of the world's silver as a by-product of mining and processing these metals.
Silver combines the highest thermal conductivity of any metal with the highest electrical conductivity.
Solid silver, as used for cutlery and ornaments, is never completely pure because it would be too soft - it is usually mixed with 5 per cent copper to form the alloy known as sterling silver. In jewelry the copper content can be as high as 20 per cent. Base metals can be electroplated with silver, as in EPNS (electroplated nickel silver) ware, in which an alloy of copper and nickel called nickel silver is plated with a thin layer of silver. Before the advent of the electroplating technique in 1840, an alternative method of plating was used in which a copper block was heated and pressed between two silver plates so that two pressure welds were formed. The complete sandwich could then be rolled down to any thickness, the product being known as Sheffield plate.
Another application, which utilizes the high reflectivity of silver, is in the coating of mirrors. The surface to be treated is immersed in a mixed solution of silver nitrate, and ammonium hydroxide and the silver is precipitated out onto the glass by adding a suitable reducing agent.
Dentists' amalgam used for filling teeth consists of an alloy of silver (70 per cent) and tin with small amounts of copper and zinc which is dissolved in mercury (with approximately equal proportions of mercury alloy). When mixed it is plastic but shortly after mixing - when the filling is in place - a reaction occurs to give a hard silver- tin-mercury compound which should last for may years.
The most important user of silver compounds is the photographic industry, which consumes thousands of tons annually as chloride and bromide salts, AgCl and AgBr respectively. A photographic image is made up of myriads of minute crystals of silver. These are precipitated from the halide salt during development dependending on the amount of light to which the salt has been previously exposed in the camera. After development the image must be fixed by removing the excess silver bromide which was not activated by light during exposure.
Uses for Silver:
- Bactericides and anticeptics
- Batteries Brazing alloys and solders
- Calalysts - for chemical processes
- Capacitors - silvered mica
- Coating Wires - which carry High-Frequency Currents
- Coins
- Cutlery
- Dentistry - filling for teeth
- Electric Conductivity
- Electroplating
- Flatware
- Glass
- Jewelry
- Mirrors
- Ornaments
- Silver Nitrate - medical uses including staining cells and tissues
- Photography
- Thermal Conductivity
Silver Islet Mine
Ontario's first silver mine, Silver Islet Mine is found on a small island south of the Sibley Peninsula near Thunder Bay. The successful mining of the copper deposits of the Keeweenaw Peninsula, in northern Michigan encouraged mineral exploration around Lake Superior. As part of this activity, an exploration license for five miles of frontage by two miles deep, at the southern end of Sibley Peninsula, was granted to John Woods. Because of royalties on metals, and the remoteness of the location, exploration was only cursory. John Woods then sold or transferred the land to the Montreal Mining Company.
In 1868 the Montreal Mining Company was surveying the Wood's Location, because the government was about to levy a tax of two cents an acre on the property. While breaking rocks to install a location stake on an island 80' by 80' they found the first vein of silver. A barrel full of samples shipped to Montreal was valued at between $10,000 and $12,000.
The first winter a crew blasted the vein with black powder and fished up pieces with long tools from under the stormy ice and water of Lake Superior. They then shipped $300,000 worth of silver ore to Wales for processing the following spring.
The small island was enlarged using wooden cribs to fit the contour of the island. The cribs were filled with rock, this enlarged the island to ten times the original, allowing a shaft to be dug and dormitories and mine buildings to be built. The cribs were washed away three times during the life of the mine.
The ore at Silver Islet consisted of native silver and argentite in quartz-calcite-dolomite veins. These veins were found along a northwest trending fault at a point where the fault cut and displaced a diabase dike. Sometimes native silver wires as thick as a man's arm were seen sticking out of the pink and white vein material in the mine.
The ore was moved to the mainland where a stamp mill was set up near the community of Silver Islet Landing. The silver vein ran out at a depth of 1,200 feet after 15 years. $3,250,000 [1880 dollars] worth of silver was extracted during that period. Two further attempts were made to reopen the mine, in 1919 when the price of silver soared on world markets and again in the 1970s, but this was not economically viable. The island is covered with trees today and the miner's cottages at Silver Islet Landing are used as summer cottages, some are still owned by family members of the miners.
Cobalt
Ore deposits were known within a few kilometres of Cobalt, Ontario over 280 years ago. An Indian guide showed voyageur The Chevalier de Troyes a mine which was a source of lead for musket balls. The voyageur and one hundred coureurs de bois were a raiding party passing through the Lake Temiskaming area on the way to the English trading post at Moose Factory.
A map entitled Carte des Lacs du Canada published in 1744 showed a spot called Ance a la Mine on the east side of Lake Timiskaming. This was the site of a silver rich galena deposit. Over 150 years later William Logan, mapping for the Geological Survey of Canada was next person to discover a vein of cobalt ore on the shore of Lake Timiskaming, about two kilometres south of Haileybury. In 1904 this became the Agaunico Mine.
Rich silver deposits were found everywhere at Cobalt in those early days. Those who made discoveries settled down and worked their ground. It did not need a large vein to make a man rich.
James McKinley and Ernest Darragh, railway tie contractors are given credit for noticing the first metallic flakes at the south end of Lake Timiskaming. On August 5, 1903 they staked a claim. One assayer reported the silver content to be 4 000 ounces per ton. This claim was sold to backers from Rochester, New York. The McKinley-Darragh Mine's final production exceeded 21 million ounces of silver.
Dr. Willet G. Miller, professor of geology from Queen's University, Kingston, and part-time provincial geologist mapped the geology of the Cobalt area. In June 1904 he took the liberty of nailing up a sign near the railway station of the new camp that proudly stated "Cobalt Station, T. and N.O. Ry." When he visited the Haileybury Hotel a few days later he found workers from the new mining camp had registered as residents of Cobalt. Soon afterwards the railway commissioners met and confirmed the new name.
The peak year of mining at Cobalt was 1911 when about 35 million ounces of silver was produced at 35 cents per ounce.