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Blue Tent, California
Blue Tent is a historic 19th century gold mining community located about six miles northeast of Nevada City, California. Its approximate location is at the intersection of N. Bloomfield Road and Blue Tent School Road. It was part of Nevada Township. Early history The community Blue Tent lies on a gold-bearing channel of an ancient river bed. The channel runs from the San Juan Ridge through Scotts Flat, California, Hunt's Hill, California, and You Bet, California to Dutch Flat, California and Placer County. Blue Tent was established in 1850 and named after its first dwelling, a tent made of blue denim. The community thrived, becoming a center for hydraulic mining. Before long, it had its own store, dance hall, blacksmith shop, boarding house and other buildings. A non-denominational Union Church was erected in 1861. Blue Tent also served as a supply base for the more remote mines in that part of Nevada County. The firm of Lindsay & Dick distributed supplies from Blue Tent by pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold Mining
Gold mining is the extraction of gold resources by mining. Historically, mining gold from alluvial deposits used manual separation processes, such as gold panning. However, with the expansion of gold mining to ores that are not on the surface, has led to more complex extraction processes such as pit mining and gold cyanidation. In the 20th and 21st centuries, most volume of mining was done by large corporations, however the value of gold has led to millions of small, artisanal miners in many parts of the Global South. Like all mining, human rights and environmental issues are common issues in the gold mining industry. In smaller mines with less regulation, health and safety risks are much higher. History The exact date that humans first began to mine gold is unknown, but some of the oldest known gold artifacts were found in the Varna Necropolis in Bulgaria. The graves of the necropolis were built between 4700 and 4200 BC, indicating that gold mining could be at least 700 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lime Kiln
A lime kiln is a kiln used for the calcination of limestone (calcium carbonate) to produce the form of lime (material), lime called quicklime (calcium oxide). The chemical equation for this chemical reaction, reaction is :Calcium carbonate, CaCO3 + heat → Calcium oxide, CaO + Carbon dioxide, CO2 This reaction can take place at anywhere above 840 °C (1544 °F), but is generally considered to occur at 900 °C(1655 °F) (at which temperature the partial pressure of CO2 is 1 atmosphere (unit), atmosphere), but a temperature around 1000 °C (1832 °F) (at which temperature the partial pressure of CO2 is 3.8 atmospheres) is usually used to make the reaction proceed quickly.Parkes, G.D. and Mellor, J.W. (1939). ''Mellor's Modern Inorganic Chemistry'' London: Longmans, Green and Co. Excessive temperature is avoided because it produces unreactive, "dead-burned" lime. Slaked lime (calcium hydroxide) can be formed by mixing quicklime with water. Early li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stamp Mill
A stamp mill (or stamp battery or stamping mill) is a type of mill machine that crushes material by pounding rather than grinding, either for further processing or for extraction of metallic ores. Breaking material down is a type of unit operation. Description A stamp mill consists of a set of heavy steel (iron-shod wood in some cases) stamps, loosely held vertically in a frame, in which the stamps can slide up and down. They are lifted by cams on a horizontal rotating shaft. As the cam moves from under the stamp, the stamp falls onto the ore below, crushing the rock, and the lifting process is repeated at the next pass of the cam. Each one frame and stamp set is sometimes called a "battery" or, confusingly, a "stamp" and mills are sometimes categorised by how many stamps they have, i.e. a "10 stamp mill" has 10 sets. They usually are arranged linearly, but when a mill is enlarged, a new line of them may be constructed rather than extending the line. Abandoned mill sites (as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Bloomfield Mining And Gravel Company
The North Bloomfield Mining and Gravel Company of North Bloomfield, California, was established in 1866 and operated a hydraulic gold-mining operation at the Malakoff Mine subsequent to the California Gold Rush. In its day, no other company's operations matched North Bloomfield Mining and Gravel Company in size or expense. The company operated until 1910. In the years prior, its profits and procedures had been reduced due to the landmark ruling of ''Woodruff v. North Bloomfield Gravel Mining Company.'' The mine is located within Malakoff Diggins State Historic Park, east of Highway 49 on Tyler Foote's Crossing Road, and north of Nevada City, California. The company office is still standing. History The North Bloomfield Mining and Gravel Company was owned by 30 investors from San Francisco, led by railroad baron Lester I. Robinson, and William Ralston, a silver miner from Sun Mountain in Nevada. The company's water rights were the same watershed as Summit Water and Irrigation C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flume
A flume is a human-made channel for water, in the form of an open declined gravity chute whose walls are raised above the surrounding terrain, in contrast to a trench or ditch. Flumes are not to be confused with aqueducts, which are built to transport water, rather than transporting materials using flowing water as a flume does. Flumes route water from a diversion dam or weir to a desired materiel collection location. Flumes are usually made up of wood, metal or concrete. Many flumes took the form of wooden troughs elevated on trestles, often following the natural contours of the land. Originating as a part of a mill race, they were later used in the transportation of logs in the logging industry, known as a log flume. They were also extensively used in hydraulic mining and working placer deposits for gold, tin and other heavy minerals. Etymology The term ''flume'' comes from the Old French word ''flum'', from the Latin ''flumen'', meaning a river. It was formerly used for a st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Yuba River
The U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed March 10, 2011 South Yuba River is a left-entering tributary of the Yuba River originating in the northern Sierra Nevada at Lake Angela in Nevada County about three quarters of a mile north of Donner Pass, about three miles east of the town of Soda Springs. After passing through Lake Van Norden with Upper Castle Creek (longer than the Lake Angela stem) entering from the right, it gathers numerous snow-fed tributaries running west through a marshy, lake-filled valley, criss-crossing Interstate 80. The river briefly enters Placer County, then flows into Lake Spaulding, then plunges westward into a steep-sided valley. Canyon Creek enters from the right, then Poorman Creek also from the right near the town of Washington. The river continues west into the foothills, crossing under State Route 49. Its mouth is on the east shore of upper Englebright Lake, formed by a dam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mortar (masonry)
Mortar is a workable paste which hardens to bind building blocks such as stones, bricks, and concrete masonry units, to fill and seal the irregular gaps between them, spread the weight of them evenly, and sometimes to add decorative colors or patterns to masonry walls. In its broadest sense, mortar includes pitch, asphalt, and soft mud or clay, as those used between mud bricks, as well as cement mortar. The word "mortar" comes from Old French ''mortier'', "builder's mortar, plaster; bowl for mixing." (13c.). Cement mortar becomes hard when it cures, resulting in a rigid aggregate structure; however, the mortar functions as a weaker component than the building blocks and serves as the sacrificial element in the masonry, because mortar is easier and less expensive to repair than the building blocks. Bricklayers typically make mortars using a mixture of sand, a binder, and water. The most common binder since the early 20th century is Portland cement, but the ancient binder lim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Cutting
Ice cutting is a winter task of collecting surface ice from lakes and rivers for storage in ice houses and use or sale as a cooling method. Rare today, it was common (see ice trade) before the era of widespread mechanical refrigeration and air conditioning technology. The work was done as a winter chore by many farmers and as a winter occupation by icemen. Kept insulated, the ice was preserved for cold food storage during warm weather, either on the farm or for delivery to residential and commercial customers with ice boxes. A large ice trade existed in the 19th and early 20th centuries, until mechanical refrigeration displaced it. Ice harvesting generally involved waiting until approximately a foot of ice had built up on the water surface in the winter. The ice would then be cut with either a handsaw or a powered saw blade into long continuous strips and then cut into large individual blocks for transport by wagon back to the ice house. Because snow on top of the ice slows fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charcoal
Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, called charcoal burning, often by forming a charcoal kiln, the heat is supplied by burning part of the starting material itself, with a limited supply of oxygen. The material can also be heated in a closed retort. Modern "charcoal" briquettes used for outdoor cooking may contain many other additives, e.g. coal. This process happens naturally when combustion is incomplete, and is sometimes used in radiocarbon dating. It also happens inadvertently while burning wood, as in a fireplace or wood stove. The visible flame in these is due to combustion of the volatile gases exuded as the wood turns into charcoal. The soot and smoke commonly given off by wood fires result from incomplete combustion of those volatiles. Charcoal burns at a higher temper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sawmill
A sawmill (saw mill, saw-mill) or lumber mill is a facility where logs are cut into lumber. Modern sawmills use a motorized saw to cut logs lengthwise to make long pieces, and crosswise to length depending on standard or custom sizes (dimensional lumber). The "portable" sawmill is of simple operation. The log lies flat on a steel bed, and the motorized saw cuts the log horizontally along the length of the bed, by the operator manually pushing the saw. The most basic kind of sawmill consists of a chainsaw and a customized jig ("Alaskan sawmill"), with similar horizontal operation. Before the invention of the sawmill, boards were made in various manual ways, either rived (split) and planed, hewn, or more often hand sawn by two men with a whipsaw, one above and another in a saw pit below. The earliest known mechanical mill is the Hierapolis sawmill, a Roman water-powered stone mill at Hierapolis, Asia Minor dating back to the 3rd century AD. Other water-powered mills followe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Powder
Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate (saltpeter). The sulfur and carbon act as fuels while the saltpeter is an oxidizer. Gunpowder has been widely used as a propellant in firearms, artillery, rocketry, and pyrotechnics, including use as a blasting agent for explosives in quarrying, mining, building pipelines and road building. Gunpowder is classified as a low explosive because of its relatively slow decomposition rate and consequently low brisance. Low explosives deflagrate (i.e., burn at subsonic speeds), whereas high explosives detonate, producing a supersonic shockwave. Ignition of gunpowder packed behind a projectile generates enough pressure to force the shot from the muzzle at high speed, but usually not enough force to rupture the gun barrel. It thus makes a good propellant but is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drift Mining
Drift mining is either the mining of an ore deposit by underground methods, or the working of coal seams accessed by adits driven into the surface outcrop of the coal bed. A drift mine is an underground mine in which the entry or access is above water level and generally on the slope of a hill, driven horizontally into the ore seam. Random House dictionary says the origin of the term "drift mine" is an Americanism, circa 1885–1890. Drift is a more general mining term, meaning a near-horizontal passageway in a mine, following the bed (of coal, for instance) or vein of ore. A drift may or may not intersect the ground surface. A drift follows the vein, as distinguished from a crosscut that intersects it, or a level or gallery, which may do either. All horizontal or subhorizontal development openings made in a mine have the generic name of drift. These are simply tunnels made in the rock, with a size and shape depending on their use—for example, haulage, ventilation, or exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
