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The chlorination of the water supply helped stop the epidemic and as a precaution, the chlorination was continued until 1911 when a new water supply was instituted. [125] Manual Control Chlorinator for the liquefaction of chlorine for water purification, early 20th century. From Chlorination of Water by Joseph Race, 1918.
The bottom part was adapted to hold a gas burner, a high pressure oil or an ordinary wood or coal fire. Superior models could have a drawing-off tap, and a steam-escape pipe that led into the flue. [1] An invoice for a free-standing Kesselofen. It was used for domestic laundry. Linen and cotton were placed in the copper and were boiled to
Combining copper with tin and/or arsenic in the right proportions produces bronze, an alloy that is significantly harder than copper. The first copper/arsenic bronzes date from 4200 BC from Asia Minor. The Inca bronze alloys were also of this type. Arsenic is often an impurity in copper ores, so the discovery could have been made by accident.
It seems that the copper was not used for the miners' tools. However copper chisels and discarded axes could be utilized as wedges. [16] Other evidence: The presence of coal and charcoal, crucial for the firing (fire-setting) and furnace (fuel), is habitual. Leather sacks (at Ai Bunar) and shoulder baskets (at Copa Hill) were used to transport ...
A Bronze Age fire-set pit. Fire-setting is a method of traditional mining used most commonly from prehistoric times up to the Middle Ages. Fires were set against a rock face to heat the stone, which was then doused with liquid, causing the stone to fracture by thermal shock. Rapid heating causes thermal shock by itself—without subsequent ...
ARCO closed the Berkeley Pit and shut off the deep pumps in 1982, allowing the pit and mines to fill with water. The Continental Pit, the last active Anaconda mining property in Butte, was closed in 1982, but resumed mining in the early 2000's. Six years after ARCO acquired rights to the "Richest Hill on Earth", Butte's mines were completely idle.
Thousands of copper mining pits have been found along the shores of Lake Superior, and Isle Royale. These pits may have been in use as far back as 8,000 years ago. This copper was mined and then made into objects such as heavy spear points and tools of all kinds.
This fact, correlated with the dramatic decrease in copper production, may indicate a possible displacement of copper and bronze artifacts by iron ones (Forbes 1957, 64; Bayley et al. 2008, 50). By the end of the 9th century, economic, and social conditions dictated a greater need for metal for agriculture, arms, stirrups , and decoration.