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Holkham Bay
Holkham Bay (also known as Sumdum Bay) is a bay in the U.S. state of Alaska. It connects Tracy Arm and Endicott Arm on its east to Stephens Passage on its west. Etymology Holkham Bay was named for Holkham, a community in Norfolk, England by George Vancouver. The Tlingit knew the bay as Sum Dum, reportedly referring to the sound of ice falling off glaciers into the water. This led to the alternate name of Sumdum Bay in use today. Some mines in the area borrow both names. History The land surrounding Holkham Bay was inhabited by Tlingit people, along with much of the rest of Southeast Alaska. European discovery and its modern name came in 1794 after Joseph Whidbey, exploring as part of the Vancouver Expedition, reported the bay upon his return to George Vancouver. Whidbey reported several hostile encounters with the Tlingit on his journey. Holkham Bay served as one of the operational bases for Canadians working to define the border with Canada to resolve the Alaska boundary dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chuck River Wilderness
Chuck River Wilderness is a wilderness area located within the Tongass National Forest in the U.S. state of Alaska. It was designated by the United States Congress The United States Congress is the legislature of the federal government of the United States. It is bicameral, composed of a lower body, the House of Representatives, and an upper body, the Senate. It meets in the U.S. Capitol in Washi ... in 1990. Located at the head of Windham Bay, Chuck River Wilderness is adjacent to the Tracy Arm-Fords Terror Wilderness. The Chuck River flows northward from its headwaters near Port Houghton through dense forest with thick vegetation before emptying into Windham Bay where the historic Chuck Mining Camp operated until the 1920s. There is private land in the lower river and in portions of the bay where there was once a small settlement. References External links Chuck River Wilderness- Tongass National Forest Chuck River Wilderness- Wilderness.net Prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vancouver Expedition
The Vancouver Expedition (1791–1795) was a four-and-a-half-year voyage of exploration and diplomacy, commanded by Captain George Vancouver of the Royal Navy. The British expedition circumnavigated the globe and made contact with five continents. The expedition at various times included between two and four vessels, and up to 153 men, all but 6 of whom returned home safely. Origin Several previous voyages of exploration including those of Ferdinand Magellan and James Cook, and the Spanish Manila-Acapulco galleons trade route active since 1565, had established the strategic and commercial value of exploring and claiming the Pacific Ocean access, both for its wealth in whales and furs and as a trade route to the " Orient". Britain was especially interested in improving its knowledge of the Southern Pacific whale fisheries, and in particular the location of the strategically positioned Australia, New Zealand, the legendary ''Isla Grande'', and the Northwest Passage. A new ship w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicious
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as a synthetic product. Notable examples include fused quartz, fumed silica, silica gel, opal and aerogels. It is used in structural materials, microelectronics (as an electrical insulator), and as components in the food and pharmaceutical industries. Structure In the majority of silicates, the silicon atom shows tetrahedral coordination, with four oxygen atoms surrounding a central Si atomsee 3-D Unit Cell. Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. In contrast, CO2 is a linear molecule. The starkly different structures of the dioxide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wharf
A wharf, quay (, also ), staith, or staithe is a structure on the shore of a harbour or on the bank of a river or canal where ships may dock to load and unload cargo or passengers. Such a structure includes one or more Berth (moorings), berths (Mooring (watercraft), mooring locations), and may also include piers, warehouses, or other facilities necessary for handling the ships. Wharves are often considered to be a series of docks at which boats are stationed. Overview A wharf commonly comprises a fixed platform, often on deep foundation, pilings. Commercial ports may have warehouses that serve as interim storage: where it is sufficient a single wharf with a single berth constructed along the land adjacent to the water is normally used; where there is a need for more capacity multiple wharves, or perhaps a single large wharf with multiple berths, will instead be constructed, sometimes projecting over the water. A pier, raised over the water rather than within it, is commonly use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tramway (industrial)
Tramways are lightly laid railways, sometimes with the wagons or carriages moved without locomotives. Because individual tramway infrastructure is not intended to carry the weight of typical standard-gauge railway equipment, the tramways over which they operate may be built from less substantial materials. Tramways can exist in many forms; sometimes just tracks temporarily placed on the ground to transport materials around a factory, mine or quarry. Many, if not most, use narrow-gauge railway technology. The trains can be manually pushed by hand, pulled by animals (especially horses and mules), cable hauled by a stationary engine, or use small, light locomotives. The term is not in use in North America but in common use in the United Kingdom, and elsewhere, where British Railway terminology and practices had large influences on management practices, terminology, and railway cultures such as Australia, New Zealand, and those parts of Asia that consulted with British experts whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelton Wheel
The Pelton wheel or Pelton Turbine is an Impulse (physics), impulse-type water turbine invented by American inventor Lester Allan Pelton in the 1870s. The Pelton wheel extracts energy from the impulse of moving water, as opposed to water's dead weight like the traditional overshot water wheel. Many earlier variations of impulse turbines existed, but they were less Energy conversion efficiency, efficient than Pelton's design. Water leaving those wheels typically still had high speed, carrying away much of the dynamic energy brought to the wheels. Pelton's paddle geometry was designed so that when the rim ran at half the speed of the water jet, the water left the wheel with very little speed; thus his design extracted almost all of the water's impulse energywhich made for a very efficient turbine. History file:Pelton wheel (patent).png, Figure from Lester Allan Pelton's original October 1880 patent Lester Allan Pelton was born in Vermillion, Ohio in 1829. In 1850, he traveled ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frue Vanner
Vanning is a type of ore dressing by which ores are washed on a shovel. Typically, a powdered sample of orestuff is swirled with water on the blade of a shovel and then given a series of upward flicking motions. The heavier ore is tossed up through the water and appears as a crescent shaped patch at the top of the charge with the lighter gangue below. Developed in western England, this process was still in use at a major tin mine and a mine waste collection firm in Cornwall until 1985. Frue Vanner In the 19th century the process was automated and used for the separation of ore on an industrial scale. The Frue vanner was one such machine that was widely adopted. It was invented in 1874, by W. B. Frue, Superintendent of the Silver Islet Mine, Ontario, Canada, who spent two years developing the system.E. Henry Davies, Machinery for Metalliferous Mines, London: C. Lockwood & Son 1894. p.320 (on Google Books) In the Frue vanner a continuous rubber belt 4 feet wide and 27½ feet lon ... [...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 (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outcrop
An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial deposits are covered by soil and vegetation and cannot be seen or examined closely. However, in places where the overlying cover is removed through erosion or tectonic uplift, the rock may be exposed, or ''crop out''. Such exposure will happen most frequently in areas where erosion is rapid and exceeds the weathering rate such as on steep hillsides, mountain ridges and tops, river banks, and tectonically active areas. In Finland, glacial erosion during the last glacial maximum (ca. 11000 BC), followed by scouring by sea waves, followed by isostatic uplift has produced many smooth coastal and littoral outcrops. Bedrock and superficial deposits may also be exposed at the Earth's surface due to human excavations such as quarrying and bui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ridge
A ridge or a mountain ridge is a geographical feature consisting of a chain of mountains or hills that form a continuous elevated crest for an extended distance. The sides of the ridge slope away from the narrow top on either side. The lines along the crest formed by the highest points, with the terrain dropping down on either side, are called the ridgelines. Ridges are usually termed hills or mountains as well, depending on size. Smaller ridges, especially those leaving a larger ridge, are often referred to as spurs. Types There are several main types of ridges: ;Dendritic ridge: In typical dissected plateau terrain, the stream drainage valleys will leave intervening ridges. These are by far the most common ridges. These ridges usually represent slightly more erosion resistant rock, but not always – they often remain because there were more joints where the valleys formed or other chance occurrences. This type of ridge is generally somewhat random in orientation, oft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slate
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. It is the finest grained foliated metamorphic rock. Foliation may not correspond to the original sedimentary layering, but instead is in planes perpendicular to the direction of metamorphic compression. The foliation in slate is called " slaty cleavage". It is caused by strong compression causing fine grained clay flakes to regrow in planes perpendicular to the compression. When expertly "cut" by striking parallel to the foliation, with a specialized tool in the quarry, many slates will display a property called fissility, forming smooth flat sheets of stone which have long been used for roofing, floor tiles, and other purposes. Slate is frequently grey in color, especially when seen, en masse, covering roofs. However, slate occurs in a variety of colors even from a single locality; f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graphite
Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large scale (300 kton/year, in 1989) for uses in pencils, lubricants, and electrodes. Under high pressures and temperatures it converts to diamond. It is a weak conductor of heat and electricity. Types and varieties Natural graphite The principal types of natural graphite, each occurring in different types of ore deposits, are * Crystalline small flakes of graphite (or flake graphite) occurs as isolated, flat, plate-like particles with hexagonal edges if unbroken. When broken the edges can be irregular or angular; * Amorphous graphite: very fine flake graphite is sometimes called amorphous; * Lump graphite (or vein graphite) occurs in fissure veins or fractures and appears as massive platy intergrowths of fibrous or acicular cry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
