A snowplow is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces those serving transportation purposes. Although this term is used to refer to vehicles mounting such devices, more they are known as winter service vehicles in areas that receive large amounts of snow every year, or in specific environments such as airfields. In other cases, pickup trucks and front end loaders are outfitted with attachments to fulfill this purpose; some regions that do not see snow may use graders to remove compacted snow and ice off the streets. Snowplows can be mounted on rail cars or locomotives to clear railway tracks. A snowplow works by using a blade to push snow to the side to clear it from a surface. Modern plows may include technology to make it easier to stay on the road; these include head-up displays and infrared cameras. Large custom snowplows are used at major airports in North America; these plows have oversized blades and additional equipment like a rotating sweeper broom and blowers at the rear of the plow.
For sidewalks and narrow lanes small tractor plows are used within Canada and the United States. When snowfall accumulates above a certain height, snowplow operators may be seen clearing the main arteries first, in some cases for the exclusive use of emergency vehicles. Underbody scrapers are sometimes mounted on vehicles in residential and urban settings, operating on principles similar to a road grader, but allowing greater weights and speed along with the carriage of a road treatment applicator. Newer technology has allowed the use of articulated plow systems which can clear multiple divided highway lanes simultaneously; the first snow plows were horse-drawn wedge-plows made of wood. With the advent of the automobile, a number of inventors set about to improve existing snow plows. In the US, the "snow-clearer" is said to have been patented as early for railways; the first snow plow built for use with motor equipment was in 1913. It was manufactured by Good Roads Machinery in Kennett Square, PA. and was designed to meet the exacting requirements outlined by engineers of the New York City Street Cleaning Bureau.
Good Roads is therefore unofficially credited as the originator of the modern snow plow, though their horse drawn steel blade road graders were used to clear roads of snow as early as the company's founding in 1878 under their original name American Road Machinery. Good Roads patented the first four-wheel grader in 1889 thus making it the first pull grading apparatus patented in the United States. Unlike most early snow plow manufacturers, Good Roads continues to manufacture snow removal equipment today under the name Good Roads Godwin, now located in Dunn, North Carolina. In the early 1920s Good Roads advertised in The American City magazine that "...three out of every four snow plows in use throughout the whole United States are Good Roads Champions." By the mid-1920s Good Roads was manufacturing snow plows of various shapes and sizes for use on a wide variety of motorized equipment. Other snow plow manufactures began to follow suit as motorized plows were proven more efficient than other methods of snow removal.
In 1923, the brothers Hans and Even Øveraasen of Norway constructed an early snowplow for use on cars. This proved to be the start of a tradition in snow-clearing equipment for roads and airports, as well as the foundation of the company Øveraasen Snow Removal Systems. Carl Frink of Clayton, New York, USA was an early manufacturer of automobile-mounted snowplows, his company, Frink Snowplows, now Frink-America, was founded by some accounts as early as 1920. Today snow plows are produced by numerous companies around the world and available for different kinds of vehicles such as service trucks, pickup trucks, SUVs and ATVs, they are installed using model specific or universal hardware and mount to the frame of the vehicle to ensure durable connection. There are manual and hydraulic operating snow plows. All necessary mounting hardware comes in set with a plow. Snow plow blades are available in various sizes depending on a vehicle type. Service trucks use a blade sized 96 in and more. Common blade size for pickup trucks and full size SUVs is 78–96 in.
Smaller ATV snow plow blades are 48–78 in wide. In many countries, railway locomotives have small snowplows permanently attached to their bogies, which serve as pilots. With others, the snowplow forms part of the obstacle deflector below the bufferbeam. Bolt-on versions exist, these attach to the bufferbeam or front coupler. However, larger snowplows exist, which tend to be conversions rather than purpose-built vehicles. Steam locomotive tenders, large diesel locomotive bogies and various freight vehicles have been used, with the snowplow body mounted on the original frames, they are one-ended, with conventional coupling equipment on the inner end. In Canada purpose built snowplow cars are in use in areas where there is a significant snow fall during winter periods; these cars were influenced by the Russell Plow from the United States
Bucket (machine part)
A bucket is a specialized container attached to a machine, as compared to a bucket adapted for manual use by a human being. It is a bulk material handling component; the bucket has an inner volume as compared to other types of machine attachments like blades or shovels. The bucket could be attached to the lifting hook of a crane, at the end of the arm of an excavating machine, to the wires of a dragline excavator, to the arms of a power shovel or a tractor equipped with a backhoe loader or to a loader, or to a dredge; the name "bucket" may have been coined from buckets used in water wheels, or used in water turbines or in similar-looking devices. Buckets in mechanical engineering can have a distinct quality from the traditional bucket whose purpose is to contain things. Larger versions of this type of bucket equip bucket trucks to contain human beings, buckets in water-hauling systems in mines or, for instance, in helicopter buckets to hold water to combat fires. Two other types of mechanical buckets can be distinguished according to the final destination of the device they equip: energy-consumer systems like excavators or energy-capturer systems like water bucket wheels or turbines.
Buckets exist in a variety of shapes. They can be quite large like those equipping Hulett cranes, used to discharge ore out of cargo ships in harbours or small such as those used by deep-sea exploration vehicles; the shape of the bucket can vary from the truncated conical shape of an actual bucket to more scoop-like or spoon-like shapes akin to water turbines. The cross section can be square; this is the same shape of a domestic form, the one-piece-standing single element, but with an augmented size. In early developments of mining, a large simple bucket allowed easy insertion of both miners and construction materials such as pit props, extraction of miners and ore. Common terms used in various parts of the world include: Bowk. Latterly they have been called sinking buckets, as they are now only used when sinking new mine shafts before insertion of the cage, or for emergency rescue. Concrete buckets help deliver concrete on a specific site of a building by the means of a tower crane, they have a bottom opening to allow concrete to flow out of the bucket.
See tremie. They are placed at the end of an excavator-like arm and have to be made from a material that provides isolation from electricity, like fiber glass, to help the workers protect themselves. There may be a door on the side of the bucket. Excavator buckets are made of solid steel and present teeth protruding from the cutting edge, to disrupt hard material and avoid wear-and-tear of the bucket. Subsets of the excavator bucket are: the ditching bucket, trenching bucket, A ditching bucket is a wider bucket with no teeth, 5–6 feet used for excavating larger excavations and grading stone. A trenching excavator bucket is 6 to 24 in wide and with protruding teeth; the clamshell bucket is a more sophisticated articulated several-piece device, including two elementary buckets associated on a hinged structure forming a claws-like appendage with an internal volume. The design is used in bucket-wheel excavators; the buckets in the wheel have to be made of solid material to withstand the resistance of the material it cuts through.
The bucket wheel design is used to capture the water energy in water-wheels or water turbines like Pelton wheels. The buckets have to be made of solid material to withstand the force of the water flow, their shape is optimized according to their purpose. Other designs include. In this case, the buckets have to be made of a light material; the buckets-ladders are used in bucket elevators or in the dredge design of some dredgers
Mining is the extraction of valuable minerals or other geological materials from the earth from an ore body, vein, reef or placer deposit. These deposits form a mineralized package, of economic interest to the miner. Ores recovered by mining include metals, oil shale, limestone, dimension stone, rock salt, potash and clay. Mining is required to obtain any material that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or water. Mining of stones and metal has been a human activity since pre-historic times. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, final reclamation of the land after the mine is closed. De Re Metallica, Georgius Agricola, 1550, Book I, Para. 1Mining operations create a negative environmental impact, both during the mining activity and after the mine has closed.
Hence, most of the world's nations have passed regulations to decrease the impact. Work safety has long been a concern as well, modern practices have improved safety in mines. Levels of metals recycling are low. Unless future end-of-life recycling rates are stepped up, some rare metals may become unavailable for use in a variety of consumer products. Due to the low recycling rates, some landfills now contain higher concentrations of metal than mines themselves. Since the beginning of civilization, people have used stone and metals found close to the Earth's surface; these were used to make early weapons. Flint mines have been found in chalk areas where seams of the stone were followed underground by shafts and galleries; the mines at Grimes Graves and Krzemionki are famous, like most other flint mines, are Neolithic in origin. Other hard rocks mined or collected for axes included the greenstone of the Langdale axe industry based in the English Lake District; the oldest-known mine on archaeological record is the Ngwenya Mine in Swaziland, which radiocarbon dating shows to be about 43,000 years old.
At this site Paleolithic humans mined hematite to make the red pigment ochre. Mines of a similar age in Hungary are believed to be sites where Neanderthals may have mined flint for weapons and tools. Ancient Egyptians mined malachite at Maadi. At first, Egyptians used the bright green malachite stones for ornamentations and pottery. Between 2613 and 2494 BC, large building projects required expeditions abroad to the area of Wadi Maghareh in order to secure minerals and other resources not available in Egypt itself. Quarries for turquoise and copper were found at Wadi Hammamat, Tura and various other Nubian sites on the Sinai Peninsula and at Timna. Mining in Egypt occurred in the earliest dynasties; the gold mines of Nubia were among the largest and most extensive of any in Ancient Egypt. These mines are described by the Greek author Diodorus Siculus, who mentions fire-setting as one method used to break down the hard rock holding the gold. One of the complexes is shown in one of the earliest known maps.
The miners crushed the ore and ground it to a fine powder before washing the powder for the gold dust. Mining in Europe has a long history. Examples include the silver mines of Laurium. Although they had over 20,000 slaves working them, their technology was identical to their Bronze Age predecessors. At other mines, such as on the island of Thassos, marble was quarried by the Parians after they arrived in the 7th century BC; the marble was shipped away and was found by archaeologists to have been used in buildings including the tomb of Amphipolis. Philip II of Macedon, the father of Alexander the Great, captured the gold mines of Mount Pangeo in 357 BC to fund his military campaigns, he captured gold mines in Thrace for minting coinage producing 26 tons per year. However, it was the Romans who developed large scale mining methods the use of large volumes of water brought to the minehead by numerous aqueducts; the water was used for a variety of purposes, including removing overburden and rock debris, called hydraulic mining, as well as washing comminuted, or crushed and driving simple machinery.
The Romans used hydraulic mining methods on a large scale to prospect for the veins of ore a now-obsolete form of mining known as hushing. They built numerous aqueducts to supply water to the minehead. There, the water stored in large tanks; when a full tank was opened, the flood of water sluiced away the overburden to expose the bedrock underneath and any gold veins. The rock was worked upon by fire-setting to heat the rock, which would be quenched with a stream of water; the resulting thermal shock cracked the rock, enabling it to be removed by further streams of water from the overhead tanks. The Roman miners used similar methods to work cassiterite deposits in Cornwall and lead ore in the Pennines; the methods had been developed by the Romans in Spain in 25 AD to exploit large alluvial gold deposits, the largest site being at Las Medulas, where seven long aqueducts tapped local rivers and sluiced the deposits. Spain was one of the most important mining regions, but all regions of the Roman Empire were exploited.
In Great Britain the natives had mined minerals for millennia, but after the Roman conquest, the scale of the operations increased as the Romans needed Britannia's resources gold, silver
A river is a natural flowing watercourse freshwater, flowing towards an ocean, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, brook and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location. Sometimes a river is defined as being larger than a creek, but not always: the language is vague. Rivers are part of the hydrological cycle. Potamology is the scientific study of rivers, while limnology is the study of inland waters in general. Most of the major cities of the world are situated on the banks of rivers, as they are, or were, used as a source of water, for obtaining food, for transport, as borders, as a defensive measure, as a source of hydropower to drive machinery, for bathing, as a means of disposing of waste.
A river begins at a source, follows a path called a course, ends at a mouth or mouths. The water in a river is confined to a channel, made up of a stream bed between banks. In larger rivers there is also a wider floodplain shaped by flood-waters over-topping the channel. Floodplains may be wide in relation to the size of the river channel; this distinction between river channel and floodplain can be blurred in urban areas where the floodplain of a river channel can become developed by housing and industry. Rivers can flow down mountains, through valleys or along plains, can create canyons or gorges; the term upriver refers to the direction towards the source of the river, i.e. against the direction of flow. The term downriver describes the direction towards the mouth of the river, in which the current flows; the term left bank refers to the left bank in the direction of right bank to the right. The river channel contains a single stream of water, but some rivers flow as several interconnecting streams of water, producing a braided river.
Extensive braided rivers are now found in only a few regions worldwide, such as the South Island of New Zealand. They occur on peneplains and some of the larger river deltas. Anastamosing rivers are quite rare, they have multiple sinuous channels carrying large volumes of sediment. There are rare cases of river bifurcation in which a river divides and the resultant flows ending in different seas. An example is the bifurcation of Nerodime River in Kosovo. A river flowing in its channel is a source of energy which acts on the river channel to change its shape and form. In 1757, the German hydrologist Albert Brahms empirically observed that the submerged weight of objects that may be carried away by a river is proportional to the sixth power of the river flow speed; this formulation is sometimes called Airy's law. Thus, if the speed of flow is doubled, the flow would dislodge objects with 64 times as much submerged weight. In mountainous torrential zones this can be seen as erosion channels through hard rocks and the creation of sands and gravels from the destruction of larger rocks.
A river valley, created from a U-shaped glaciated valley, can easily be identified by the V-shaped channel that it has carved. In the middle reaches where a river flows over flatter land, meanders may form through erosion of the river banks and deposition on the inside of bends. Sometimes the river will cut off a loop, shortening the channel and forming an oxbow lake or billabong. Rivers that carry large amounts of sediment may develop conspicuous deltas at their mouths. Rivers whose mouths are in saline tidal waters may form estuaries. Throughout the course of the river, the total volume of water transported downstream will be a combination of the free water flow together with a substantial volume flowing through sub-surface rocks and gravels that underlie the river and its floodplain. For many rivers in large valleys, this unseen component of flow may exceed the visible flow. Most but not all rivers flow on the surface. Subterranean rivers flow underground in caverns; such rivers are found in regions with limestone geologic formations.
Subglacial streams are the braided rivers that flow at the beds of glaciers and ice sheets, permitting meltwater to be discharged at the front of the glacier. Because of the gradient in pressure due to the overlying weight of the glacier, such streams can flow uphill. An intermittent river only flows and can be dry for several years at a time; these rivers are found in regions with limited or variable rainfall, or can occur because of geologic conditions such as a permeable river bed. Some ephemeral rivers flow during the summer months but not in the winter; such rivers are fed from chalk aquifers which recharge from winter rainfall. In England these rivers are called bournes and give their name to places such as Bournemouth and Eastbourne. In humid regions, the location where flow begins in the smallest tributary streams moves upstream in response to precipitation and downstream in its absence or when active summer vegetation diverts water for evapotrans
A steam shovel is a large steam-powered excavating machine designed for lifting and moving material such as rock and soil. It is the earliest type of power excavator. Steam shovels played a major role in public works in the 19th and early 20th century, being key to the construction of railroads and the Panama Canal; the development of simpler, cheaper diesel-powered shovels caused steam shovels to fall out of favor in the 1930s. Grimshaw of Boulton & Watt devised the first steam-powered excavator in 1796. In 1833 William Brunton patented another steam-powered excavator which he provided further details on in 1836; the steam shovel was invented by William Otis, who received a patent for his design in 1839. The first machines were known as'partial-swing', since the boom could not rotate through 360 degrees, they were built on a railway chassis, on which the movement engines were mounted. The shovel arm and driving engines were mounted at one end of the chassis, which accounts for the limited swing.
Bogies with flanged wheels were fitted, power was taken to the wheels by a chain drive to the axles. Temporary rail tracks were laid by workers where the shovel was expected to work, repositioned as required. Steam shovels became more popular in the latter half of the nineteenth century. Configured with chain hoists, the advent of steel cable in the 1870s allowed for easier rigging to the winches. Machines were supplied with caterpillar tracks, obviating the need for rails; the full-swing, 360° revolving shovel was developed in England in 1884, became the preferred format for these machines. Expanding railway networks fostered a demand for steam shovels; the extensive mileage of railways, corresponding volume of material to be moved, forced the technological leap. As a result, steam shovels became commonplace. American manufacturers included the Marion Steam Shovel Company, founded in 1884, Erie and Bucyrus-Erie Shovel Companies; the booming cities in North America used shovels to dig foundations and basements for the early skyscrapers.
The most famous application of steam shovels is the digging of the Panama Canal across the Isthmus of Panama. One hundred and two shovels worked in that decade-long dig. Of these, seventy-seven were built by Bucyrus; these machines'moved mountains' in their labours. The shovel crews would race to see. Steam shovels assisted mining operations: the iron mines of Minnesota, the copper mines of Chile and Montana, placer mines of the Klondike – all had earth-moving equipment, but it was with the burgeoning open-pit mines – first in Bingham Canyon, Utah – that shovels came into their own. The shovels systematically removed hillsides; as a result, steam shovels were used around the world from Australia to Russia to coal mines in China. Shovels were used for construction and quarry work. Steam shovels came into their own in the 1920s with the publicly funded road building programs around North America. Thousands of miles of State Highways were built in this time period, together with new factories, such as Henry Ford's River Rouge Plant, many docks, ports and grain elevators.
During the 1930s steam shovels lost out to the simpler, cheaper diesel-powered excavating shovels that were the forerunners of those still in use today. Open-pit mines were electrified at this time. Only after the Second World War, with the advent of robust high-pressure hydraulic hoses, did the more versatile hydraulic excavators take pre-eminence over the cable-hoisting winch shovels. Many steam shovels remained at work on the railways of developing nations until diesel engines supplanted them. Most have since been scrapped. Large, multi-ton mining shovels still use the cable-lift shovel arrangement. In the 1950s and 1960s Marion Shovel built massive stripping shovels for coal operations in the Eastern US. Shovels of note were the Marion 360, the Marion 5900, the largest shovel built, Marion 6360 The Captain – with a 180-cubic-yard bucket – while Bucyrus constructed one of the most famous monsters: the Big Brutus, the largest still in existence; the GEM of Egypt, which operated from 1967 to 1988, was of comparable size.
Although these big machines are still called steam shovels, they are more known as power shovels since they use electricity to wind their winches. A steam shovel consists of: a bucket with a toothed edge, to dig into the earth a "dipper" or "dipper stick" connecting the bucket to the boom a "boom" mounted on the rotating platform, supporting the dipper and its control wires a boiler a water tank and coal bunker steam engines and winches operator's controls a rotating platform on a truck, on which everything is mounted wheels a house to contain and protect'the works'The shovel has several individual operations: it can raise or luff the boom, rotate the house, or extend the dipper stick with the boom or crowd engine, raise or lower the dipper stick; when digging at a rock face, the operator raises and extends the dipper stick to fill the bucket with material. When the bucket is full, the shovel is rotated to load a railway motor truck; the locking pin on the bucket flap is released and the load drops away.
The operator lowers the dipper stick, the bucket mouth self-closes, the pin relocks automatically and the process repeats. Steam shovels had a three-man crew: engineer and ground man. There was much jockeying to do to move shovels: rails and timber blocks to move.
Dredging is the operation of removing material from one part of the water environment and relocating it to another. In all but a few situations the excavation is undertaken by a specialist floating plant, known as a dredger. Dredging is carried out in many different locations and for many different purposes, but the main objectives are to recover material that has some value or use, or to create a greater depth of water. Dredging is the form of excavation carried out underwater or underwater, in shallow waters or ocean waters, it keeps waterways and ports navigable, assists coastal protection, land reclamation and coastal redevelopment, by gathering up bottom sediments and transporting it elsewhere. Dredging can be done to recover materials of commercial value. Dredging is a four-part process: loosening the material, bringing the material to the surface and disposal; the material can be brought to the surface by mechanical means. The extract can be disposed of locally or transported by barge or in a liquid suspension in kilometre long pipelines.
Disposal can be to infill sites, or the material can be used constructively to replenish eroded sand, lost to coastal erosion, or constructively create sea-walls, building land or whole new landforms such as viable islands in coral atolls. Ancient authors refer to habour dredging; the seven arms of the Nile were channelled and wharfs built at the time of the pyramids, there was extensive harbour building in the eastern Mediterranean from 1000 BC and the disturbed sediment layers gives evidence of dredging. At Marseille, dredging phases are recorded from the third century BC onwards, the most extensive during the first century AD; the remains of three dredging boats have been unearthed. Dredging machines were used during the construction of the Suez Canal. During the renaissance da Vinci drew a design for a drag dredger. Maintenance: dredging to deepen or maintain navigable waterways or channels which are threatened to become silted with the passage of time, due to sedimented sand and mud making them too shallow for navigation.
This is carried out with a trailing suction hopper dredge. Most dredging is for this purpose, it may be done to maintain the holding capacity of reservoirs or lakes. Land reclamation: dredging to mine sand, clay or rock from the seabed and using it to construct new land elsewhere; this is performed by a cutter-suction dredge or trailing suction hopper dredge. The material may be used for flood or erosion control. Capital dredging: dredging carried out to create a new harbour, berth or waterway, or to deepen existing facilities in order to allow larger ships access; because capital works involve hard material or high-volume works, the work is done using a cutter suction dredge or large trailing suction hopper dredge. Preparatory: dredging work and excavation for future bridges, piers or docksor wharves, This is to build the foundations. Winning construction materials: dredging sand and gravels from offshore licensed areas for use in construction industry, principally for use in concrete; this specialist industry is focused in NW Europe, it uses specialized trailing suction hopper dredgers self discharging the dry cargo ashore.
Contaminant remediation: to reclaim areas affected by chemical spills, storm water surges, other soil contaminations, including silt from sewage sludge and from decayed matter, like wilted plants. Disposal becomes a proportionally large factor in these operations. Flood prevention: dredging increases the channel depth and therefore increase a channel's capacity for carrying water. Fishing dredging is a technique for catching certain species of edible crabs. In Louisiana and other American states, with salt water estuaries that can sustain bottom oyster beds, oysters are raised and harvested. A heavy rectangular metal scoop is towed astern of a moving boat with a chain bridle attached to a cable; this drags along the bottom scooping up oysters. It is periodically winched aboard and the catch is sorted and bagged for shipment. Harvesting materials: dredging sediment for elements like gold, diamonds or other valuable trace substances. Hobbyists examine their dredged matter to pick out items of potential value, similar to the hobby of metal detecting.
Beach nourishment: this is mining sand offshore and placing on a beach to replace sand eroded by storms or wave action. This enhances the recreational and protective function of the beach, which are eroded by human activity; this is performed by a cutter-suction dredge or trailing suction hopper dredge. Peat extraction: dredging poles or dredge hauls were used on the back of small boats to manually dredge the beds of peat-moor waterways; the extracted peat was used as a fuel. This tradition is now less obsolete; the tools are now changed. Removing rubbish and debris: done in combination with maintenance dredging, this process removes non-natural matter from the bottoms of rivers and canals and harbours. Law enforcement agencies sometimes need to use a'drag' to recover evidence or corpses from beneath the water. Anti-eutrophication: A kind of contaminant remediation, dredging is an expensive option for the remediation of eutrophied water bodies. However, as artificially elevated phosphorus levels in the sediment aggravate the eutrophication process, controlled sed