Facts:
Zinc, also known as Spelter, is the fourth most common metal produced following Iron, Aluminum and Copper. It is the 23rd most abundant element in the earth's crust, found in air, water and the biosphere (plants, animals and humans). Three-fourths of all Zinc mined is used as a coating to protect iron and steel from corrosion, a process called galvanization. Zinc is also an alloying metal in the production of Brass, Bronze and other metals. It has a melting point of 419°C and a boiling point of 907°C. It is a lustrous blue-white metal, brittle at low temperatures, but malleable from 110 to 150°C. Zinc is a heavier metal than Iron, but a lighter metal than Lead.
Mining:
Australia, Canada, China, Peru and the U.S. are the leading producers of Zinc. Due to the nature of Zinc ore veins, 80% of Zinc mines are underground, 8% are open pit mines and the remainder being a combination of the two. In terms of production volume, open pit mines account for 15%, with underground mines accounting for 64%.
Production:
Before mined ore is pure enough to be used directly by smelters, it needs to be concentrated. Zinc ores, containing 5 to 15% Zinc, are roasted to temperatures nearing 1000°C. This roasting causes the Zinc Sulphide (ZnS), within the ore, to be converted into Zinc Oxide (ZnO). At the same time, Sulphur reacting with Oxygen creates Sulphur Dioxide (SO2), which is subsequently converted to Sulphuric Acid (H2SO4). This roasting eventually creates a vaporous mixture of Zinc and Lead, which is then cooled, but kept in a molten state. The Zinc content, within this molten mass, is then separated from the Lead content and is now ready for shipping to foundries. At this point, Zinc, with a purity of 99.95%, can be used in the galvanization processes or as an alloying agent with Copper, Aluminum or Magnesium.
Deposits:
Broken Hill Type (BHT)
Named for a class of ore deposits located beneath Broken Hill in New South Wales, Australia. Broken Hill is arguably the world's largest, and richest, deposit of Zinc and Lead ores. This type of ore deposit is associated with sedimentary Sandstone and Siltstone terranes. A terrane is a fragment of the earth’s crustal material, that is either, on, or broken off from, one tectonic plate and accreted (sutured) to another plate.
Volcanic Hosted Massive Sulphides (VMS)
Transport of these ores occurs by way of hydrothermal activity. Underground water, heated by a magma chamber, circulates and leeches particles from the host ores. Further heating alters this liquid to steam, which is then expelled via fumaroles or black smokers. Once cooled by ocean waters, these Sulfide minerals, settle onto the ocean floor in layers (stratification). These Sulfide ore deposits are an important source of Copper and Zinc, and often contain significant concentrations of Silver, Gold, Tin, Bismuth or Cadmium.
Intrusion related (vein)
These deposits are typically an intrusive type of deposit found in Carbonate rock (Limestone). They were formed between 65.5 million years ago, and the present, making them Cenozoic in age. A flow of incompatible fluid elements, escaping from a cooling Granite mass below the earth's surface, formed this type of deposit. These concentrations typically contain larger amounts of exceptional grade Silver and low-grade Lead and smaller concentrations of Zinc.
Carbonate hosted (Mississippi Valley and Irish types)
Carbonate deposits are primarily found in Limestone (Calcite) and Dolostone (Dolomite). Zinc and Lead content within these Carbonate deposits range from 5 to 10%. Deposits of Copper, Silver, Calcium Fluorite and Barite are also found within these rocks.
Sediment hosted (Sedex - Sedimentary Exhalative)
This type of ore deposit is also formed by hydrothermal activity. Circulation of water results in the precipitation (leeching), transport and deposition of ore-bearing fluids into a water reservoir, usually an ocean. These deposits are then covered by other sediments such as Shale, Sandstone and Siltstone. Some of the world’s largest accumulations of Zinc, Lead and Silver have been uncovered in these Sedex deposits. The Zinc and Lead content within these deposits can range from 10 to 20%.
Compounds:
Sphalerite (ZnS) (A Carbonate) is the main ore of Zinc. It consists largely of Zinc Sulfide (ZnS) and Iron (Fe). It can be shiny or dull, is typically black, but can be of various other colors. It is used in the making of luminous watch dials, television screens and fluorescent light bulbs.
Calamine (A Silicate) is a mixture of Zinc Oxide (ZnO) with about 0.5% Iron (III) oxide (Fe2O3). It is the main ingredient in Calamine lotion, an anti-itching agent, used to treat poison ivy, chickenpox, insect bites and stings.
Franklinite (An Oxide) is found in the world famous mines around Franklin, New Jersey. This small area of New Jersey is famous for producing many formerly unknown and exotic mineral ores, found nowhere else on earth. Franklinite was named in honor of Benjamin Franklin, the American statesman.
Smithsonite (ZnCO3) (A Carbonate) comes from the weathering (oxidation) of Zinc bearing ore deposits. It is used as fireproofing filler for rubber and plastics, as a pigment in cosmetics and lotions, and in the manufacturing of porcelain and pottery. It is sometimes polished and used as an ornamental stone called Bonamite. Smithsonite was named for James Smithson who proved that Zinc Carbonates were true carbonate minerals, not Zinc Oxides. After his death in 1829, the Smithson Estate was given to the United States to found the Smithsonian Institution.
Willemite (Zn2SiO4) (A Silicate) occurs as a secondary Zinc mineral produced by the weathering of Sphalerite in hydrothermal veins. It contains Manganese, Iron, and Magnesium as a replacement for part of the Zinc ore. Samples of Willemite fluoresce, bright green, when placed under an ultra-violet light source. Some samples will also phosphoresce, making them a “must have” for any serious rock collector. It was originally discovered, in 1830, and named for William I of the Netherlands.
Zincite (ZnO) (Zinc Oxide), although rare worldwide, is the major ore of the mines of Franklin, New Jersey. Ores from here normally contain roughly 80% Zinc by weight and are found in isolated massive formations within Limestone. Zincite crystals also grow within vent pipes of Zinc smelting plants. Formerly known as philosopher's wool, Zincite is used as a white pigment in the production of paint and an ultraviolet light absorber in the prevention of sunburn.
Casting:
In 1873, M.A. Richardson and C.J. Willard perfected a method of casting Zinc, allowing for the mass production of grave markers, hollow statues and other decorations. After a century outdoors, most of these markers are in surprisingly excellent condition. Unlike their stone counterparts that become unreadable and covered in lichens and mosses, these monuments have resisted weathering and plant growth.
Between 1879 and 1914, the Monumental Bronze Company produced castable Zinc statuary. Marketed as “Superior to stone” in terms of durability, their products were referred to as "White Bronze." A process of sandblasting, oiling and pressurized steam spraying gave their monuments an appearance of natural stone. These "White Bronze" memorials included thousands of grave markers, effigies of the dead and statues of Faith, Hope and Charity. Many cities have Monumental Bronze made Civil War memorials rising over the graves and sites of great battles. The company’s original records show that its statues were standing in town squares, courthouse lawns and parks in 31 states.
At the same time, the companies of J.W. Fiske and J.L. Mott Iron Works, created and sold Cast Iron and Cast Zinc statues that were “painted or bronzed.” Their Elk Stag monuments became famous centerpieces for the "Benevolent Order of Elks" rest memorials. Their statuary is found worldwide.
Founded in 1860, the Daprato Statuary Company introduced "copper-plated" statuary, some of which was also painted. Each monument was marked with a brass plaque indicating the Company trademark. As production and sales by other companies waned, Daprato products continued to sell, and were distributed worldwide. The Daprato Statuary Company finally closed its doors in 1932.
Damage:
Common damage to all Zinc statuary includes breakage of the brittle metal from concussion, separation of soldered seams, pitting and from a process called "Creep." Creep occurs when; the weight of the statuary itself causes its lower edges to expand outward, eventually breaking the base of the casting. Creep is the most serious preservation and restoration problem of the multitude of statues, monuments and memorials found throughout the world.
Items required:
A. A GPSr.
B. A printout of this page.
C. A magnet.
Waypoints:
WP #1. N44 28.950 W88 01.634
WP #2. N44 29.408 W88 01.249
WP #3. N44 26.382 W88 03.281
Email your answers to the questions, to me, using the link in my profile only. If your answers are not recieved by me, your log will be deleted. Photos are accepted and appreciated as long as the answers are not pictured. You do not have to wait for confirmation from me before logging this cache as completed. Most of all……learn……and enjoy the view.
At Waypoint #1:
A. Does this statuary display signs of creep, pitting, cracking or other damage?
B. Is the finished surface steam blasted, painted or bronzed?
C. Which of the above mentioned companies created this piece of statuary?
At Waypoint #2:
A. Is the finished surface steam blasted, painted or bronzed?
B. In what year was this statuary dedicated?
C. Which of the above mentioned companies created this piece of statuary?
At Waypoint #3:
A. Does this statuary display signs of creep, pitting, cracking or other damage?
B. Does this statuary attract a magnet?
C. Is the finished surface steam blasted, painted or bronzed?
D. Which of the above mentioned companies created this piece of statuary?
