Misplaced Pages

#365634

141-561: Wet Earth Colliery was a coal mine located on the Manchester Coalfield , in Clifton , Greater Manchester . The colliery site is now the location of Clifton Country Park . The colliery has a unique place in British coal mining history; apart from being one of the earliest pits in the country, it is the place where engineer James Brindley made water run uphill. The colliery is situated in

282-450: A partial vacuum ; for siphons in vacuum he concluded: "The gravitational force on the column of liquid in the downtake tube less the gravitational force in the uptake tube causes the liquid to move. The liquid is therefore in tension and sustains a longitudinal strain which, in the absence of disturbing factors, is insufficient to break the column of liquid". But for siphons of small uptake height working at atmospheric pressure, he wrote: "...

423-697: A 70% increase over the 20 years since 1999. In 2018, the world production of brown coal (lignite) was 803.2 Mt, with Germany the world's largest producer at 166.3 Mt. China is most likely the second largest producer and consumer of lignite globally although specific lignite production data is not made available. Coal production has grown fastest in Asia, while Europe has declined. Since 2011, world coal production has been stable, with decreases in Europe and US offset by increases from China, Indonesia and Australia. The top coal mining nations are: Energy production from coal mining

564-473: A blockage of air, following which an explosion occurred in which he was badly burnt. William and John Ivill (father and son) came to his aid, but during the descent of the shaft were overcome by blackdamp and fell 300 feet from the cage to their deaths. A serious fire continued for several days. The area around Wet Earth Colliery was abandoned, leaving much of the Gal Pit and surrounding buildings intact. Over

705-407: A chain hanging over a pulley, with one end of the chain piled on a higher surface than the other. Since the length of chain on the shorter side is lighter than the length of chain on the taller side, the heavier chain on the taller side will move down and pull up the chain on the lighter side. Similar to a siphon, the chain model is obviously just powered by gravity acting on the heavier side, and there

846-426: A chain, which has significant tensile strength, liquids usually have little tensile strength under typical siphon conditions, and therefore the liquid on the rising side cannot be pulled up in the way the chain is pulled up on the rising side. An occasional misunderstanding of siphons is that they rely on the tensile strength of the liquid to pull the liquid up and over the rise. While water has been found to have

987-467: A coal seam occurring near the top of a ridge or hill, the entire top is removed in a series of parallel cuts. Overburden is deposited in nearby valleys and hollows. This method usually leaves the ridge and hilltops as flattened plateaus. The process is highly controversial for the drastic changes in topography, the practice of creating head-of-hollow-fills , or filling in valleys with mining debris, and for covering streams and disrupting ecosystems. Spoil

1128-417: A constant trickle of clean water being fed to the cistern by a slightly open valve. While if both ends of a siphon are at atmospheric pressure, liquid flows from high to low, if the bottom end of a siphon is pressurized, liquid can flow from low to high. If pressure is removed from the bottom end, the liquid flow will reverse, illustrating that it is pressure driving the siphon. An everyday illustration of this

1269-496: A deeper place outside a connection is built, using a tube or some pipes. They are filled with water through an intake valve (at the highest end of the construction). When the ends are opened, the water flows through the pipe into the sewer or the river. Siphoning is common in irrigated fields to transfer a controlled amount of water from a ditch, over the ditch wall, into furrows. Large siphons may be used in municipal waterworks and industry. Their size requires control via valves at

1410-446: A downcast shaft to the Doe mine and equipped it with a steam-powered winding engine. The original single shaft Gal Pit had given problems with access, ventilation and getting coal out of the mine. The second shaft gave the pit a new lease of life and production increased. The old gin winding mechanism on the Gal Pit was abandoned when the second shaft was opened. On the death of Ellis in 1834,

1551-580: A few hundred yards to the north of the Wet Earth Colliery shows evidence of early bell pit working and small ladder pits. The first deeper working was by the owner of the Clifton Estate, John Heathcote of Glossop in Derbyshire in the 1740s. Heathcote sank two shafts, which were about 50 feet (15 m) deep to the Doe mine . This seam was 9 ft 7½ in thick and dipped at a gradient of 1 in 3½ to

SECTION 10

#1732851914366

1692-405: A fourth of the world's energy. Coal extraction methods vary depending on whether the mine is an underground mine or a surface (also called an open cast) mine. Additionally, coal seam thickness and geology are factors in the selection of a mining method. The most economical method of coal extraction for surface mines is the electric shovel or drag line. The most economical form of underground mining

1833-403: A greater proportion of the coal deposit than underground methods, as more of the coal seams in the strata may be exploited. This equipment can include the following: Draglines which operate by removing the overburden, power shovels, large trucks in which transport overburden and coal, bucket wheel excavators, and conveyors. In this mining method, explosives are first used in order to break through

1974-440: A land use condition is not equal to the original use. Existing land uses (such as livestock grazing, crop and timber production) are temporarily eliminated in mining areas. High-value, intensive-land-use areas like urban and transportation systems are not usually affected by mining operations. If mineral values are sufficient, these improvements may be removed to an adjacent area. Strip mining eliminates existing vegetation, destroys

2115-476: A large bend in the river as far as Giant's Seat. By this point the river had crossed the Pendleton Fault, where it curved 180 degrees to flow northwest, and had begun to curve back to resume its southeasterly course past Wet Earth Colliery. At Giant's Seat, Brindley drove two shafts into the sandstone, one each north and south of the river. An adit was also driven from the northern shaft to the river bank allowing

2256-440: A large dining-room table, but with hydraulic jacks for legs. After the large pillars of coal have been mined away, the mobile roof support's legs shorten and it is withdrawn to a safe area. The mine roof typically collapses once the mobile roof supports leave an area. There are six principal methods of underground mining: Coal is mined commercially in over 50 countries. 7,921 million metric tons (Mt) of coal were produced in 2019,

2397-414: A long-term method to limit leakage hazard in the retaining wall. Siphon drainage is also used in draining unstable slopes, and siphon roof-water drainage systems have been in use since the 1960s. A siphon spillway in a dam is usually not technically a siphon, as it is generally used to drain elevated water levels. However, a siphon spillway operates as an actual siphon if it raises the flow higher than

2538-447: A method that currently accounts for about 60 percent of world coal production. In deep mining, the room and pillar or bord and pillar method progresses along the seam, while pillars and timber are left standing to support the mine roof. Once room and pillar mines have been developed to a stopping point limited by geology, ventilation, or economics, a supplementary version of room and pillar mining, termed second mining or retreat mining ,

2679-402: A more functional siphon that does not require constant re-priming and restarting. In this respect, where the requirement is to match a flow into a container with a flow out of said container (to maintain a constant level in a pond fed by a stream, for example) it would be preferable to utilize two or three smaller separate parallel pipes that can be started as required rather than attempting to use

2820-415: A much larger weight of liquid in it, and yet the lighter volume of liquid in the down tube can pull liquid up the fatter up tube, and the siphon can function normally. Another difference is that under most practical circumstances, dissolved gases, vapor pressure, and (sometimes) lack of adhesion with tube walls, conspire to render the tensile strength within the liquid ineffective for siphoning. Thus, unlike

2961-406: A new coal mine. Siphon#Inverted siphon There are two leading theories about how siphons cause liquid to flow uphill, against gravity, without being pumped, and powered only by gravity. The traditional theory for centuries was that gravity pulling the liquid down on the exit side of the siphon resulted in reduced pressure at the top of the siphon. Then atmospheric pressure was able to push

SECTION 20

#1732851914366

3102-475: A pressure differential within the siphon tube and the tensile strength of the liquid are required for a siphon to operate. A researcher at Humboldt State University , A. McGuire, examined flow in siphons in 2012. Using the advanced general-purpose multiphysics simulation software package LS-DYNA he examined pressure initialisation, flow, and pressure propagation within a siphon. He concluded: "Pressure, gravity and molecular cohesion can all be driving forces in

3243-490: A pressure differential, writing: "As the fluid initially primed on the long leg of the siphon rushes down due to gravity, it leaves behind a partial vacuum that allows pressure on the entrance point of the higher container to push fluid up the leg on that side". The research team of Boatwright, Puttick, and Licence, all at the University of Nottingham , succeeded in running a siphon in high vacuum , also in 2011. They wrote: "It

3384-756: A relative of John Heathcote, was an engineer whose feats included the Bridgewater Canal , the Trent and Mersey Canal and later the Chester Canal , as well as the Harecastle Tunnel . He initially suggested a scheme whereby a Newcomen atmospheric pumping engine could be used to dewater the mine but the Newcomen engine had been plagued with problems in dewatering deep mines. His revised scheme relied on water power. It had to overcome several obstacles, not least that there

3525-574: A result of occupational exposures is coined occupational hearing loss . To protect miners' hearing, the US Mine Safety and Health Administration 's (MSHA) guidelines for noise place a Permissible Exposure Limit (PEL) for noise at 90 dBA time-weighted over 8 hours. A lower cutoff, 85 dBA, is set for a worker to fall into the MSHA Action Level which dictates that workers be placed into hearing conservation programs. Noise exposures vary depending on

3666-493: A short tunnel. Entering the pumping chamber next to the pit head, the water turned a 23-foot (7 m) diameter overshot waterwheel that powered a nodding donkey or pumpjack . The water pumped out of the mine then exited along with the tail race through another tunnel back into the Irwell. Construction started in 1752 and the scheme was completed by 1756. It was so successful that the basic components remained in use for 170 years;

3807-442: A significant tensile strength in some experiments (such as with the z-tube ), and siphons in vacuum rely on such cohesion, common siphons can easily be demonstrated to need no liquid tensile strength at all to function. Furthermore, since common siphons operate at positive pressures throughout the siphon, there is no contribution from liquid tensile strength, because the molecules are actually repelling each other in order to resist

3948-404: A single large pipe and attempting to throttle it. Siphons are sometimes employed as automatic machines, in situations where it is desirable to turn a continuous trickling flow or an irregular small surge flow into a large surge volume. A common example of this is a public restroom with urinals regularly flushed by an automatic siphon in a small water tank overhead. When the container is filled, all

4089-422: A siphon. Their conclusion was: "It follows from the above analysis that there must be a direct cohesive connection between water molecules flowing in and out of a siphon. This is true at all atmospheric pressures in which the pressure in the apex of the siphon is above the vapour pressure of water, an exception being ionic liquids". A plain tube can be used as a siphon. An external pump has to be applied to start

4230-510: A tunnel was driven to connect to the Plodder Mine, which gave the mine a further lease of life until the river found a crack in the fault and flooded it and it was abandoned. Other seams were starting to be work out and, coupled with a miners' strike in 1921, the colliery was run down and closed in 1928. There were at least 38 deaths at the colliery. There were many other injuries and incidents, one being on 17 May 1874. Thomas Entwistle discovered

4371-413: A vacuum"), which dates to Aristotle , and which Galileo restated as resintenza del vacuo , but this was subsequently disproved by later workers, notably Evangelista Torricelli and Blaise Pascal  – see barometer: history . A practical siphon, operating at typical atmospheric pressures and tube heights, works because gravity pulling down on the taller column of liquid leaves reduced pressure at

Wet Earth Colliery - Misplaced Pages Continue

4512-575: Is accomplished by drilling holes into the overburden, filling the holes with explosives, and detonating the explosive. The overburden is then removed, using large earth-moving equipment, such as draglines , shovel and trucks, excavator and trucks, or bucket-wheels and conveyors. This overburden is put into the previously mined (and now empty) strip. When all the overburden is removed, the underlying coal seam will be exposed (a 'block' of coal). This block of coal may be drilled and blasted (if hard) or otherwise loaded onto trucks or conveyors for transport to

4653-401: Is being lifted), while the pressure at the top of the tube from the bottom reservoir is lower (since more water is being lifted), and since liquids move from high pressure to low pressure, the liquid flows across the horizontal tube from the top basin to the bottom basin. The liquid is under positive pressure (compression) throughout the tube, not tension. Bernoulli's equation is considered in

4794-424: Is clearly no violation of conservation of energy, because the chain is ultimately just moving from a higher to a lower location, as the liquid does in a siphon. There are a number of problems with the chain model of a siphon, and understanding these differences helps to explain the actual workings of siphons. First, unlike in the chain model of the siphon, it is not actually the weight on the taller side compared to

4935-427: Is commonly started. Miners remove the coal in the pillars, thereby recovering as much coal from the coal seam as possible. A work area involved in pillar extraction is called a pillar section. Modern pillar sections use remote-controlled equipment, including large hydraulic mobile roof-supports, which can prevent cave-ins until the miners and their equipment have left a work area. The mobile roof supports are similar to

5076-418: Is dedicated to mining activities until it can be reshaped and reclaimed. If mining is allowed, resident human populations must be resettled off the mine site; economic activities, such as agriculture or hunting and gathering food and medicinal plants are interrupted. What becomes of the land surface after mining is determined by the manner in which the mining is conducted. Usually reclamation of disturbed lands to

5217-406: Is different from the common demonstration self-starting siphons in that there are ways the siphon can fail to function which require manual intervention to return to normal surge flow operation. A video demonstration of a self-starting siphon can be found here , courtesy of The Curiosity Show . The most common failure is for the liquid to dribble out slowly, matching the rate that the container

5358-430: Is filling, and the siphon enters an undesired steady-state condition. Preventing dribbling typically involves pneumatic principles to trap one or more large air bubbles in various pipes, which are sealed by water traps. This method can fail if it cannot start working intermittently without water already present in parts of the mechanism, and which will not be filled if the mechanism starts from a dry state. A second problem

5499-516: Is highly concentrated in certain jurisdictions, which also concentrates much of the social and economic impacts of the industry to these regions. The industry directly employs over seven million workers worldwide, which, in turn, creates millions of indirect jobs. In several parts of the world, producers have reached peak coal as some economies shift away from fossil fuels to address climate change. A 2020 study found that renewables jobs could feasibly be created in these geographies to replace many of

5640-399: Is lower because the tube is longer (there is more water pushing down), and requires that the lower reservoir is lower than the upper reservoir, or more generally that the discharge outlet simply be lower than the surface of the upper reservoir. Considering now the horizontal tube connecting them, one sees that the pressure at the top of the tube from the top reservoir is higher (since less water

5781-479: Is mostly used to generate electricity, and 75% of annual coal production is exported, mostly to eastern Asia. In 2007, 428 million tonnes of coal was mined in Australia. In 2007, coal provided about 85% of Australia's electricity production. In the fiscal year 2008/09, 487 million tonnes of coal was mined, and 261 million tonnes was exported. In the fiscal year 2013/14, 430.9 million tonnes of coal

Wet Earth Colliery - Misplaced Pages Continue

5922-435: Is not much larger than necessary. Using piping of too great a diameter and then throttling the flow using valves or constrictive piping appears to increase the effect of previously cited concerns over gases or vapor collecting in the crest which serve to break the vacuum. If the vacuum is reduced too much, the siphon effect can be lost. Reducing the size of pipe used closer to requirements appears to reduce this effect and creates

6063-402: Is not required for the operation of a siphon, but: "The basic explanation of siphon action is that, once the tube is filled, the flow is initiated by the greater pull of gravity on the fluid on the longer side compared with that on the short side. This creates a pressure drop throughout the siphon tube, in the same sense that 'sucking' on a straw reduces the pressure along its length all the way to

6204-417: Is partially economically recoverable. Coal refuse is distinct from the byproducts of burning coal, such as fly ash . Piles of coal refuse can have significant negative environmental consequences, including the leaching of iron, manganese, and aluminum residues into waterways and acid mine drainage . The runoff can create both surface and groundwater contamination. The piles also create a fire hazard, with

6345-593: Is placed at the head of a narrow, steep-sided valley or hollow. In preparation for filling this area, vegetation and soil are removed and a rock drain constructed down the middle of the area to be filled, where a natural drainage course previously existed. When the fill is completed, this underdrain will form a continuous water runoff system from the upper end of the valley to the lower end of the fill. Typical head-of-hollow fills are graded and terraced to create permanently stable slopes. Most coal seams are too deep underground for opencast mining and require underground mining,

6486-436: Is referred to as 'overburden' and is removed in long strips. The overburden from the first strip is deposited in an area outside the planned mining area and referred to as out-of-pit dumping. Overburden from subsequent strips is deposited in the void left from mining the coal and overburden from the previous strip. This is referred to as in-pit dumping. It is often necessary to fragment the overburden by use of explosives. This

6627-515: Is removed and overburden dumped to the side. Dust, vibration, and diesel exhaust odors are created (affecting sight, sound, and smell). Residents of local communities often find such impacts disturbing or unpleasant. In case of mountaintop removal , tops are removed from mountains or hills to expose thick coal seams underneath. The soil and rock removed is deposited in nearby valleys, hollows and depressions, resulting in blocked (and contaminated) waterways. Removal of soil and rock overburden covering

6768-701: Is still common, with 4,000 new cases of black lung every year in the US (4 percent of workers annually) and 10,000 new cases every year in China (0.2 percent of workers). The use of water sprays in mining equipment reduces the risk to miners' lungs. Build-ups of a hazardous gas are known as damps, possibly from the German word Dampf which means steam or vapor: Noise is also a contributing factor to potential adverse effects on coal miners' health. Exposure to excessive noise can lead to noise-induced hearing loss . Hearing loss developed as

6909-418: Is that the trapped air pockets will shrink over time if the siphon is not operating due to no inflow. The air in pockets is absorbed by the liquid, which pulls liquid up into the piping until the air pocket disappears, and can cause activation of water flow outside the normal range of operating when the storage tank is not full, leading to loss of the liquid seal in lower parts of the mechanism. A third problem

7050-464: Is the long wall, which involves using two spinning drums with carbide bits that runs along sections of the coal seam. Many coals extracted from both surface and underground mines require washing in a coal preparation plant . Technical and economic feasibility are evaluated based on the following: regional geological conditions; overburden characteristics; coal seam continuity, thickness, structure, quality, and depth; strength of materials above and below

7191-435: Is used for both thermal and metallurgical coals . In New South Wales open casting for steam coal and anthracite is practiced. Surface mining accounts for around 80 percent of production in Australia, while in the US it is used for about 67 percent of production. Globally, about 40 percent of coal production involves surface mining. Strip mining exposes coal by removing earth above each coal seam. This earth to be removed

SECTION 50

#1732851914366

7332-404: Is used to automatically empty the gauge. It is often simply called a "siphon gauge" and is not to be confused with a siphon pressure gauge. A siphon drainage method is being implemented in several expressways as of 2022. Recent studies found that it can reduce groundwater level behind expressway retaining walls, and there was no indication of clogging. This new drainage system is being pioneered as

7473-439: Is where the lower end of the liquid seal is simply a U-trap bend in an outflow pipe. During vigorous emptying, the kinetic motion of the liquid out the outflow can propel too much liquid out, causing a loss of the sealing volume in the outflow trap and loss of the trapped air bubble to maintain intermittent operation. A fourth problem involves seep holes in the mechanism, intended to slowly refill these various sealing chambers when

7614-510: Is widely believed that the siphon is principally driven by the force of atmospheric pressure. An experiment is described that shows that a siphon can function even under high-vacuum conditions. Molecular cohesion and gravity are shown to be contributing factors in the operation of a siphon; the presence of a positive atmospheric pressure is not required". Writing in Physics Today in 2011, J. Dooley from Millersville University stated that both

7755-482: The Industrial Revolution , and coal provided the main source of primary energy for industry and transportation in industrial areas from the 18th century to the 1950s. Coal remains an important energy source. Coal is also mined today on a large scale by open pit methods wherever the coal strata strike the surface or are relatively shallow. Britain developed the main techniques of underground coal mining from

7896-414: The surface of the source reservoir, as sometimes is the case when used in irrigation. In operation, a siphon spillway is considered to be "pipe flow" or "closed-duct flow". A normal spillway flow is pressurized by the height of the reservoir above the spillway, whereas a siphon flow rate is governed by the difference in height of the inlet and outlet. Some designs make use of an automatic system that uses

8037-618: The valley of the River Irwell which flows north to south along the Pendleton Fault . Many other coal mines were situated on this major fault which threw up the underlying Carboniferous coal measures by some 1,100 yards making them accessible for mining from early times. To the east of the fault is the red Triassic sandstone, to the west are the coal measures, which in places outcrop at surface. The area around Nob End in Kearsley ,

8178-557: The 1880s has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United Kingdom and South Africa , a coal mine and its structures are a colliery , a coal mine is called a "pit", and above-ground mining structures are referred to as a " pit head ". In Australia , "colliery" generally refers to an underground coal mine. Coal mining has had many developments in recent years, from

8319-588: The Doe coal seam. A memorial tablet was placed on a cottage at the site showing that Fletcher was responsible for sinking the shaft. The tablet has been lost but a photograph of it is stored in Swinton Library. By late 1790, a surface canal connected Wet Earth Colliery to Botany Bay Colliery. This opened fully in 1791. Fletcher linked this canal to the Manchester, Bolton and Bury Canal enabling him to get coal from mine to

8460-577: The Fletchers lost all interest and sold the mines to the Pilkington brothers, who founded the Pilkington Tile Company on a site close to the Gal Pit. In 1838 the Manchester and Bolton Railway opened, and Dixon Fold railway station was built just to the south of Wet Earth Colliery. The Pilkingtons undertook the final phase of expansion at the pit. The surface equipment was replaced and the coal

8601-787: The U.S., Examples include the Sago Mine disaster of 2006, and the 2007 mine accident in Utah 's Crandall Canyon Mine , where nine miners were killed and six entombed. In the decade 2005–2014, US coal mining fatalities averaged 28 per year. The most fatalities during the 2005–2014 decade were 48 in 2010, the year of the Upper Big Branch Mine disaster in West Virginia, which killed 29 miners. Chronic lung diseases, such as pneumoconiosis (black lung) were once common in miners, leading to reduced life expectancy . In some mining countries black lung

SECTION 60

#1732851914366

8742-608: The US Department of Labor's Mine Safety and Health Administration (MSHA) show that between 1990 and 2004, the industry cut the rate of injuries by more than half and fatalities by two-thirds. But according to the Bureau of Labor Statistics , even in 2006, mining remained the second most dangerous occupation in America, when measured by fatality rate . These numbers, however, include all mining activities, and oil and gas mining contribute to

8883-660: The United States and proposed mines under development. The coal mining industry employs almost 2.7 million workers. The History of coal mining goes back thousands of years, with early mines documented in ancient China, the Roman Empire and other early historical economies. It became important in the Industrial Revolution of the 19th and 20th centuries, when it was primarily used to power steam engines, heat buildings and generate electricity. Coal mining continues as an important economic activity today, but has begun to decline due to

9024-459: The accidental swallowing of gasoline, or aspirating it into the lungs, which can cause death or lung damage. ) If the tube is flooded with liquid before part of the tube is raised over the intermediate high point and care is taken to keep the tube flooded while it is being raised, no pump is required. Devices sold as siphons often come with a siphon pump to start the siphon process. In some applications it can be helpful to use siphon tubing that

9165-418: The air bubble down and out of the tube. The apparatus will then continue to operate as a normal siphon. As there is no contact between the liquid on either side of the siphon at the beginning of this experiment, there can be no cohesion between the liquid molecules to pull the liquid over the rise. It has been suggested by advocates of the liquid tensile strength theory, that the air start siphon only demonstrates

9306-887: The basic mechanism of a siphon does not depend upon atmospheric pressure." Gravity , pressure and molecular cohesion were the focus of work in 2010 by Hughes at the Queensland University of Technology . He used siphons at air pressure and his conclusion was: "The flow of water out of the bottom of a siphon depends on the difference in height between the inflow and outflow, and therefore cannot be dependent on atmospheric pressure…" Hughes did further work on siphons at air pressure in 2011 and concluded: "The experiments described above demonstrate that ordinary siphons at atmospheric pressure operate through gravity and not atmospheric pressure". The father and son researchers Ramette and Ramette successfully siphoned carbon dioxide under air pressure in 2011 and concluded that molecular cohesion

9447-407: The bottom ( dregs ) or the top ( foam and floaties) from being transferred out of one container into a new container. Siphoning is thus useful in the fermentation of wine and beer for this reason, since it can keep unwanted impurities out of the new container. Self-constructed siphons, made of pipes or tubes, can be used to evacuate water from cellars after floodings. Between the flooded cellar and

9588-403: The bubble out. Another common misconception about siphons is that because the atmospheric pressure is virtually identical at the entrance and exit, the atmospheric pressure cancels, and therefore atmospheric pressure cannot be pushing the liquid up the siphon. But equal and opposite forces may not completely cancel if there is an intervening force that counters some or all of one of the forces. In

9729-418: The bubbles to move against the liquid flow; though other designs call for a shallow slope in the outlet leg as well to allow the bubbles to be carried out of the siphon. At the crest the gas can be trapped in a chamber above the crest. The chamber needs to be occasionally primed again with liquid to remove the gas. A siphon rain gauge is a rain gauge that can record rainfall over an extended period. A siphon

9870-407: The chain model can be instructive. Further, in other settings water transport does occur due to tension, most significantly in transpirational pull in the xylem of vascular plants . Water and other liquids may seem to have no tensile strength because when a handful is scooped up and pulled on, the liquids narrow and pull apart effortlessly. But liquid tensile strength in a siphon is possible when

10011-581: The coal mining jobs as part of a just transition ; however, renewable energy was not suitable in some of the geographies with high concentrations of miners, such as in China, which is far and away the leading coal-mining nation. Coal refuse (also described as coal waste, rock, slag, coal tailings, waste material, rock bank, culm, boney, or gob ) is the material left over from coal mining, usually as tailings piles or spoil tips . For every tonne of hard coal generated by mining, 400 kg (880 lb) of waste material remains, which includes some lost coal that

10152-497: The coal preparation (or wash) plant. Once this strip is empty of coal, the process is repeated with a new strip being created next to it. This method is most suitable for areas with flat terrain. Equipment to be used depends on geological conditions. For example, to remove overburden that is loose or unconsolidated, a bucket wheel excavator might be the most productive. The life of some area mines may be more than 50 years. The contour mining method consists of removing overburden from

10293-857: The coal resource may cause burial and loss of topsoil, exposes parent material, and creates large infertile wastelands. Soil disturbance and associated compaction result in conditions conducive to erosion. Soil removal from the area to be surface-mined alters or destroys many natural soil characteristics, and reduces its biodiversity and productivity for agriculture. Soil structure may be disturbed by pulverization or aggregate breakdown. Top 10 hard and brown coal producers in 2012 were (in million metric tons): China 3,621, United States 922, India 629, Australia 432, Indonesia 410, Russia 351, South Africa 261, Germany 196, Poland 144, and Kazakhstan 122. Coal has been mined in every state of Australia, but mainly in Queensland, New South Wales and Victoria. It

10434-467: The coal wharfs in Manchester some 6 miles (10 km) away. Although started in 1791, the canal was not linked and navigable until 1800. At the same time, a small canal was cut to connect to a basin constructed inside the mine next to the shaft to enable coal to be loaded directly onto barges and then to Manchester. This 1½ mile section of canal became known as Fletcher's Canal . In January 1804 Matthew Fletcher's nephew, Ellis Fletcher (1765–1834), sank

10575-399: The crest and if enough accumulates to break the flow of liquid, the siphon stops working. The siphon itself will exacerbate the problem because as the liquid is raised through the siphon, the pressure drops, causing dissolved gases within the liquid to come out of solution. Higher temperature accelerates the release of gas from liquids so maintaining a constant, low temperature helps. The longer

10716-444: The crest of the siphon to start the flow of water which then completely empties the contents of the cistern into the toilet bowl. The advantage of this system was that no water would leak from the cistern excepting when flushed. These were mandatory in the UK until 2011. Early urinals incorporated a siphon in the cistern which would flush automatically on a regular cycle because there was

10857-429: The developed world. Modern coal mining in the US has an average 23 deaths per year due to mine accidents (2001–2020). However, in lesser developed countries and some developing countries, many miners continue to die annually, either through direct accidents in coal mines or through adverse health consequences from working under poor conditions. China , in particular, has the highest number of coal mining related deaths in

10998-455: The disruptive activities of blasting, ripping, and excavating coal. Stripping of overburden eliminates and destroys archeological and historic features, unless they are removed beforehand. The removal of vegetative cover and activities associated with the construction of haul roads, stockpiling of topsoil, displacement of overburden and hauling of soil and coal increase the quantity of dust around mining operations. Dust degrades air quality in

11139-408: The double-concentric siphon. Siphons were studied further in the 17th century, in the context of suction pumps (and the recently developed vacuum pumps ), particularly with an eye to understanding the maximum height of pumps (and siphons) and the apparent vacuum at the top of early barometers . This was initially explained by Galileo Galilei via the theory of horror vacui ("nature abhors

11280-424: The early days of men tunneling, digging, and manually extracting the coal on carts to large open-cut and longwall mines. Mining at this scale requires the use of draglines , trucks, conveyors , hydraulic jacks , and shearers. The coal mining industry has a long history of significant negative environmental impacts on local ecosystems, health impacts on local communities and workers, and contributes heavily to

11421-414: The effect as the siphon starts, but that the situation changes after the bubble is swept out and the siphon achieves steady flow. But a similar effect can be seen in the flying-droplet siphon (see above). The flying-droplet siphon works continuously without liquid tensile strength pulling the liquid up. The siphon in the video demonstration operated steadily for more than 28 minutes until the upper reservoir

11562-503: The example of two carts being pushed up opposite sides of a hill. As shown in the diagram, even though the person on the left seems to have his push canceled entirely by the equal and opposite push from the person on the right, the person on the left's seemingly canceled push is still the source of the force to push the left cart up. In some situations siphons do function in the absence of atmospheric pressure and due to tensile strength – see vacuum siphons  – and in these situations

11703-571: The fatalities occurring in the first half of the 20th century. 3,242 died in 1907, the worst year ever; in 2020 there were five. Open cut hazards are principally mine wall failures and vehicle collisions; underground mining hazards include suffocation, gas poisoning, roof collapse, rock burst , outbursts , and gas explosions. Firedamp explosions can trigger the far more dangerous coal dust explosions, which can engulf an entire mine. Most of these risks are greatly reduced in modern mines, and multiple fatality incidents are now rare in most parts of

11844-406: The flow of water in a spiral vortex to remove the air above to prime the siphon. Such a design includes the volute siphon. Flush toilets often have some siphon effect as the bowl empties. Some toilets also use the siphon principle to obtain the actual flush from the cistern . The flush is triggered by a lever or handle that operates a simple diaphragm-like piston pump that lifts enough water to

11985-421: The flying droplet siphon, where gases do not exert significant pulling forces, and liquids not in contact cannot exert a cohesive tension force. All known published theories in modern times recognize Bernoulli’s equation as a decent approximation to idealized, friction-free siphon operation. Egyptian reliefs from 1500 BC depict siphons used to extract liquids from large storage jars. Physical evidence for

12126-457: The genetic soil profile, displaces or destroys wildlife and habitat, alters current land uses, and to some extent permanently changes the general topography of the area mined. Adverse impacts on geological features of human interest may occur in a coal strip mine. Geomorphic and geophysical features and outstanding scenic resources may be sacrificed by indiscriminate mining. Paleontological, cultural, and other historic values may be endangered due to

12267-399: The global environmental crises, such as poor air quality and climate change . For these reasons, coal has been one of the first fossil fuels to be phased out of various parts of the global energy economy . The major coal producing countries, though, such as China , Indonesia, India and Australia , have not reached peak production, with production increases replacing falls in Europe and

12408-450: The immediate area, has an adverse impact on vegetative life, and constitutes health and safety hazards for mine workers and nearby residents. Surface mining disrupts virtually all aesthetic elements of the landscape. Alteration of land forms often imposes unfamiliar and discontinuous configurations. New linear patterns appear as material is extracted and waste piles are developed. Different colors and textures are exposed as vegetative cover

12549-407: The intake point. The ambient atmospheric pressure at the intake point responds to the reduced pressure by forcing the fluid upwards, sustaining the flow, just as in a steadily sucked straw in a milkshake." Again in 2011, Richert and Binder (at the University of Hawaii ) examined the siphon and concluded that molecular cohesion is not required for the operation of a siphon but relies upon gravity and

12690-404: The intake, outlet and crest of the siphon. The siphon may be primed by closing the intake and outlets and filling the siphon at the crest. If intakes and outlets are submerged, a vacuum pump may be applied at the crest to prime the siphon. Alternatively the siphon may be primed by a pump at either the intake or outlet. Gas in the liquid is a concern in large siphons. The gas tends to accumulate at

12831-460: The late 18th century onward, with further progress being driven by 19th-century and early 20th-century progress. However, oil and gas were increasingly used as alternatives from the 1860s onward. By the late 20th century, coal was, for the most part, replaced in domestic as well as industrial and transportation usage by oil , natural gas or electricity produced from oil, gas, nuclear power or renewable energy sources. By 2010, coal produced over

12972-402: The level falls below the intake, allowing air or other surrounding gas to break the siphon, or until the outlet of the siphon equals the level of the reservoir, whichever comes first. In addition to atmospheric pressure , the density of the liquid, and gravity , the maximal height of the crest in practical siphons is limited by the vapour pressure of the liquid. When the pressure within

13113-411: The liquid adheres to the tube walls and thereby resists narrowing. Any contamination on the tube walls, such as grease or air bubbles, or other minor influences such as turbulence or vibration, can cause the liquid to detach from the walls and lose all tensile strength. In more detail, one can look at how the hydrostatic pressure varies through a static siphon, considering in turn the vertical tube from

13254-453: The liquid drops to below the liquid's vapor pressure, tiny vapor bubbles can begin to form at the high point, and the siphon effect will end. This effect depends on how efficiently the liquid can nucleate bubbles; in the absence of impurities or rough surfaces to act as easy nucleation sites for bubbles, siphons can temporarily exceed their standard maximal height during the extended time it takes bubbles to nucleate. One siphon of degassed water

13395-409: The liquid flowing and prime the siphon (in home use this is often done by a person inhaling through the tube until enough of it has filled with liquid; this may pose danger to the user, depending on the liquid that is being siphoned). This is sometimes done with any leak-free hose to siphon gasoline from a motor vehicle's gasoline tank to an external tank. (Siphoning gasoline by mouth often results in

13536-409: The liquid from the upper reservoir, up into the reduced pressure at the top of the siphon, like in a barometer or drinking straw , and then over. However, it has been demonstrated that siphons can operate in a vacuum and to heights exceeding the barometric height of the liquid. Consequently, the cohesion tension theory of siphon operation has been advocated, where the liquid is pulled over

13677-413: The liquid is in the siphon, the more gas is released, so a shorter siphon overall helps. Local high points will trap gas so the intake and outlet legs should have continuous slopes without intermediate high points. The flow of the liquid moves bubbles thus the intake leg can have a shallow slope as the flow will push the gas bubbles to the crest. Conversely, the outlet leg needs to have a steep slope to allow

13818-436: The lower-pressure zone at the top of the siphon, over the top, and then, with the help of gravity and a taller column of liquid, down to the higher-pressure zone at the exit. The chain model is a useful but not completely accurate conceptual model of a siphon. The chain model helps to understand how a siphon can cause liquid to flow uphill, powered only by the downward force of gravity. A siphon can sometimes be thought of like

13959-404: The majority of fatalities. Coal mining resulted in 47 fatalities that year. One study, though, has suggested that hazards of modern mining are now more accretive with workers facing long-term health impacts, such as sleep deprivation, that build up over time. Strip mining severely alters the landscape, which reduces the value of the natural environment in the surrounding land. The land surface

14100-461: The method of extraction. For example, a study has found that among surface coal mine operations, dragline equipment produced the loudest sound at a range of 88–112 dBA. Within longwall sections, stageloaders used to transport coal from the mining face and shearers used for extraction represent some of the highest noise exposures. Auxiliary fans (up to 120 dBA), continuous mining machines (up to 109 dBA), and roof bolters (up to 103 dBA) represent some of

14241-465: The mining workforce. in 2015 US coal mines had 65,971 employees, the lowest figure since EIA began collecting data in 1978. However, a 2016 study reported that a relatively minor investment would allow most coal workers to retrain for the solar energy industry. Coal mining has been a very dangerous activity and the list of historical coal mining disasters is long. In the U.S., 104,895 coal miners were killed in mine accidents since 1900, 90 percent of

14382-469: The noisiest equipment within continuous mining sections. Exposures to noise exceeding 90 dBA can lead to adverse effects on workers' hearing. The use of administrative controls and engineering controls can be used to reduce noise exposures. Improvements in mining methods (e.g. longwall mining), hazardous gas monitoring (such as safety-lamps or more modern electronic gas monitors), gas drainage, electrical equipment , and ventilation have reduced many of

14523-403: The old penstock and turbine house and some restoration has been completed. Notes Footnotes Bibliography Further reading 53°31′59″N 2°20′32″W  /  53.53306°N 2.34222°W  / 53.53306; -2.34222 Coal mine Coal mining is the process of extracting coal from the ground or from a mine. Coal is valued for its energy content and since

14664-585: The open pit methods, due to thickness of the seam 20–25 metres (60–90 feet). Coals occurring below 90 m (300 ft) are usually deep mined. However, there are open pit mining operations working on coal seams up to 300–460 metres (1,000–1,500 feet) below ground level, for instance Tagebau Hambach in Germany. When coal seams are near the surface, it may be economical to extract the coal using open-cut , also referred to as open-cast, open-pit, mountaintop removal or strip, mining methods. Opencast coal mining recovers

14805-596: The operation of siphons". In 2014, Hughes and Gurung (at the Queensland University of Technology) ran a water siphon under varying air pressures ranging from sea level to 11.9 km ( 39 000  ft ) altitude. They noted: "Flow remained more or less constant during ascension indicating that siphon flow is independent of ambient barometric pressure ". They used Bernoulli's equation and the Poiseuille equation to examine pressure differentials and fluid flow within

14946-421: The operation reaches a predetermined stripping ratio (tons of overburden/tons of coal), it is not profitable to continue. Depending on the equipment available, it may not be technically feasible to exceed a certain height of highwall. At this point, it is possible to produce more coal with the augering method in which spiral drills bore tunnels into a highwall laterally from the bench to extract coal without removing

15087-488: The original waterwheel was replaced by a water turbine in 1867. At some point between the 1750 pit closure and the 1756 reopening, John Heathcote signed over ownership of Wet Earth Colliery to Matthew Fletcher. After the reopening, Fletcher sank a new 159-foot (48 m) deep 13-foot (4.0 m) diameter shaft at Wet Earth, known as Gal Pit from the Galloway ponies traditionally used as pit ponies . Gal Pit reached as far as

15228-408: The overburden. Mountaintop coal mining is a surface mining practice involving removal of mountaintops to expose coal seams, and disposing of associated mining overburden in adjacent "valley fills." Valley fills occur in steep terrain where there are limited disposal alternatives. Mountaintop removal mining combines area and contour strip mining methods. In areas with rolling or steep terrain with

15369-407: The pit was taken over by his sons Ellis Jnr and John. In 1835, a year after his father John died, Ellis Jnr lost interest, barely keeping the pit going until his own death in 1854. The pit then passed to Charlotte Anne Fletcher. A succession of family, cousins, uncles and sons of these relatives variously owned or worked the mines for the next few years. By 1880, the seams had been almost worked out and

15510-425: The potential to spontaneously ignite. Because most coal refuse harbors toxic components, it is not easily reclaimed by replanting with plants like beach grasses. The use of sophisticated sensing equipment to monitor air quality is common and has replaced the use of small animals such as canaries, often referred to as " miner's canaries ". In the United States, the increase in technology has significantly decreased

15651-423: The pressure, rather than pulling on each other. To demonstrate, the longer lower leg of a common siphon can be plugged at the bottom and filled almost to the crest with liquid as in the figure, leaving the top and the shorter upper leg completely dry and containing only air. When the plug is removed and the liquid in the longer lower leg is allowed to fall, the liquid in the upper reservoir will then typically sweep

15792-399: The risks of rock falls, explosions, and unhealthy air quality. Gases released during the mining process can be recovered to generate electricity and improve worker safety with gas engines . Another innovation in recent years is the use of closed circuit escape respirators , respirators that contain oxygen for situations where mine ventilation is compromised. Statistical analyses performed by

15933-452: The same principle. The ratio of heights (about 13.6) equals the ratio of densities of water and mercury (at a given temperature), since the column of water (resp. mercury) is balancing with the column of air yielding atmospheric pressure, and indeed maximal height is (neglecting vapor pressure and velocity of liquid) inversely proportional to density of liquid. In 1948, Malcolm Nokes investigated siphons working in both air pressure and in

16074-408: The scientific literature to be a fair approximation to the operation of the siphon. In non-ideal fluids, compressibility, tensile strength and other characteristics of the working fluid (or multiple fluids) complicate Bernoulli's equation. Once started, a siphon requires no additional energy to keep the liquid flowing up and out of the reservoir. The siphon will draw liquid out of the reservoir until

16215-418: The seam for roof and floor conditions; topography, especially altitude and slope; climate; land ownership as it affects the availability of land for mining and access; surface drainage patterns; groundwater conditions; availability of labor and materials; coal purchaser requirements in terms of tonnage, quality, and destination; and capital investment requirements. Surface mining and deep underground mining are

16356-565: The seam in a pattern following the contours along a ridge or around the hillside. This method is most commonly used in areas with rolling to steep terrain. It was once common to deposit the spoil on the downslope side of the bench thus created, but this method of spoil disposal consumed much additional land and created severe landslide and erosion problems. To alleviate these problems, a variety of methods were devised to use freshly cut overburden to refill mined-out areas. These haul-back or lateral movement methods generally consist of an initial cut with

16497-401: The shorter side that matters. Rather it is the difference in height from the reservoir surfaces to the top of the siphon, that determines the balance of pressure . For example, if the tube from the upper reservoir to the top of the siphon has a much larger diameter than the taller section of tube from the lower reservoir to the top of the siphon, the shorter upper section of the siphon may have

16638-494: The siphon in a way similar to the chain fountain . It need not be one theory or the other that is correct, but rather both theories may be correct in different circumstances of ambient pressure. The atmospheric pressure with gravity theory cannot explain siphons in vacuum, where there is no significant atmospheric pressure. But the cohesion tension with gravity theory cannot explain CO 2 gas siphons, siphons working despite bubbles, and

16779-500: The siphon is dry. The seep holes can be plugged by debris and corrosion, requiring manual cleaning and intervention. To prevent this, the siphon may be restricted to pure liquid sources, free of solids or precipitate. Many automatic siphons have been invented going back to at least the 1850s, for automatic siphon mechanisms that attempt to overcome these problems using various pneumatic and hydrodynamic principles. When certain liquids needs to be purified, siphoning can help prevent either

16920-421: The siphon pushing down (until one reaches the maximal height of a barometer/siphon, at which point the liquid cannot be pushed higher) – the hydrostatic pressure at the top of the tube is then lower than atmospheric pressure by an amount proportional to the height of the tube. Doing the same analysis on the tube rising from the lower reservoir yields the pressure at the top of that (vertical) tube; this pressure

17061-446: The siphon, the atmospheric pressure at the entrance and exit are both lessened by the force of gravity pulling down the liquid in each tube, but the pressure on the down side is lessened more by the taller column of liquid on the down side. In effect, the atmospheric pressure coming up the down side does not entirely "make it" to the top to cancel all of the atmospheric pressure pushing up the up side. This effect can be seen more easily in

17202-461: The south-west and outcrops in the river valley. Wet Earth Colliery was begun in 1751 when Heathcote sank a deep shaft to the seam about half a mile to the south-east but he ran into technical difficulties and had to call on the help of Matthew Fletcher. Jacob Fletcher, a mine owner from Bolton , had several mines in Harwood , Breightmet , Bolton and Atherton . He had two sons, John and Matthew . John

17343-432: The spoil deposited downslope or at some other site and spoil from the second cut refilling the first. A ridge of undisturbed natural material 15 to 20 ft (5 to 6 m) wide is often intentionally left at the outer edge of the mined area. This barrier adds stability to the reclaimed slope by preventing spoil from slumping or sliding downhill. The limitations of contour strip mining are both economic and technical. When

17484-490: The stored liquid is released, emerging as a large surge volume that then resets and fills again. One way to do this intermittent action involves complex machinery such as floats, chains, levers, and valves, but these can corrode, wear out, or jam over time. An alternate method is with rigid pipes and chambers, using only the water itself in a siphon as the operating mechanism. A siphon used in an automatic unattended device needs to be able to function reliably without failure. This

17625-556: The strong contribution coal plays in global warming and environmental issues, which result in decreasing demand and in some geographies, peak coal . Compared to wood fuels , coal yields a higher amount of energy per unit mass, specific energy or massic energy, and can often be obtained in areas where wood is not readily available. Though it was used historically as a domestic fuel, coal is now used mostly in industry, especially in smelting and alloy production, as well as electricity generation . Large-scale coal mining developed during

17766-476: The surface or overburden, of the mining area. The overburden is then removed by draglines or by shovel and truck. Once the coal seam is exposed, it is drilled, fractured and thoroughly mined in strips. The coal is then loaded onto large trucks or conveyors for transport to either the coal preparation plant or directly to where it will be used. Most open cast mines in the United States extract bituminous coal . In Canada, Australia, and South Africa, open cast mining

17907-403: The tension of the liquid column is neutralized and reversed by the compressive effect of the atmosphere on the opposite ends of the liquid column." Potter and Barnes at the University of Edinburgh revisited siphons in 1971. They re-examined the theories of the siphon and ran experiments on siphons in air pressure. They concluded: "By now it should be clear that, despite a wealth of tradition,

18048-410: The top of the siphon (formally, hydrostatic pressure when the liquid is not moving). This reduced pressure at the top means gravity pulling down on the shorter column of liquid is not sufficient to keep the liquid stationary against the atmospheric pressure pushing it up into the reduced-pressure zone at the top of the siphon. So the liquid flows from the higher-pressure area of the upper reservoir up to

18189-417: The top reservoir, the vertical tube from the bottom reservoir, and the horizontal tube connecting them (assuming a U-shape). At liquid level in the top reservoir, the liquid is under atmospheric pressure, and as one goes up the siphon, the hydrostatic pressure decreases (under vertical pressure variation ), since the weight of atmospheric pressure pushing the water up is counterbalanced by the column of water in

18330-408: The tunnel to be flushed when needed. Brindley connected the shafts with a 73-yard (67 m) tunnel under the river, forming an inverted syphon . At the top of the southern shaft, an open leat or head race was dug southeast along the west bank of the Irwell. This small feeder canal flowed 235 yards (215 m) until just past the Wet Earth Colliery and then sharply west to enter the mine through

18471-524: The two basic methods of mining. The choice of mining method depends primarily on depth, density, overburden, and thickness of the coal seam; seams relatively close to the surface, at depths less than approximately 55 m (180 ft), are usually surface mined. Coal that occurs at depths of 55 to 90 m (180 to 300 ft) are usually deep mined, but in some cases surface mining techniques can be used. For example, some western U.S. coal that occur at depths in excess of 60 m (200 ft) are mined by

18612-549: The use of siphons by Greeks are the Justice cup of Pythagoras in Samos in the 6th century BC and usage by Greek engineers in the 3rd century BC at Pergamon . Hero of Alexandria wrote extensively about siphons in the treatise Pneumatica . The Banu Musa brothers of 9th-century Baghdad invented a double-concentric siphon, which they described in their Book of Ingenious Devices . The edition edited by Hill includes an analysis of

18753-441: The world, with official statistics claiming that 6,027 deaths occurred in 2004. To compare, 28 deaths were reported in the U.S. in the same year. Coal production in China is twice that in the US, while the number of coal miners is around 50 times that of the US, making deaths in coal mines in China 4 times as common per worker (108 times as common per unit output) as in the US. Mine disasters have still occurred in recent years in

18894-514: The years, most of the material has been removed but there remains an area where the original workings can be seen. Salford City Council has designated the area part of the Clifton Country Park and made efforts to restore what is left and laid out a trail to guide visitors along Fletcher's Canal, past the river valley workings connected with Brindley's inverted siphon to the now capped Gal Pit. Wet Earth Colliery Exploration Group has excavated

19035-411: Was 3' 7" thick. The workings were plagued with water, which entered from the River Irwell via the Pendleton Fault . Heathcote asked Matthew Fletcher to advise him on how to solve the flooding, but it seems he was unsuccessful. John Heathcote closed the pit in 1750. Heathcote and Fletcher were at a loss as how to remove the water from the pit until it came to the attention of James Brindley . Brindley,

19176-411: Was demonstrated to 24  m (79 feet ) for an extended period of time and other controlled experiments to 10  m (33 feet ). For water at standard atmospheric pressure , the maximal siphon height is approximately 10 m (33 feet); for mercury it is 76 cm (30 inches ), which is the definition of standard pressure. This equals the maximal height of a suction pump , which operates by

19317-414: Was empty. Another simple demonstration that liquid tensile strength is not needed in the siphon is to simply introduce a bubble into the siphon during operation. The bubble can be large enough to entirely disconnect the liquids in the tube before and after the bubble, defeating any liquid tensile strength, and yet if the bubble is not too big, the siphon will continue to operate with little change as it sweeps

19458-559: Was loaded and shipped without washing to save time and money. Output under the Pilkingtons doubled and the Clifton and Kersley Coal Company was formed. The brothers deepened the shaft sunk by Ellis Fletcher, to reach the Trencherbone mine at a depth of 607 feet (185 m). During this period, further seams were worked including the Cannel, Victoria, Crumbouke and Five Quarters mines. In 1910,

19599-531: Was mined, and 375.1 million tonnes was exported. In 2013/14, coal provided about 69% of Australia's electricity production. In 2013, Australia was the world's fifth-largest coal producer, after China, the United States, India, and Indonesia. However, in terms of proportion of production exported, Australia is the world's second largest coal exporter, as it exports roughly 73% of its coal production. Indonesia exports about 87% of its coal production. A court in Australia has cited climate change in ruling against

19740-498: Was no flowing water on the site to power a pump and that the pithead was 23 feet (7 m) above the level of the River Irwell. The problem of water level was solved by building a weir upstream on the Irwell as it flowed southeast at Ringley Fold to create a head of water higher than the pithead. Drawing water from the east side of the Irwell, Brindley then drove a tunnel 800 yards (732 m) long through shale and sandstone across

19881-584: Was responsible for sinking a pit in Atherton whilst Matthew took up mining engineering. John Heathcote was having problems with the pit and called on Matthew Fletcher to help sink a new shaft. The new shaft was sunk 262 feet (80 m) to the seam at a point which became the central focus of the Wet Earth complex. The shaft was deepened to 328 feet (100 m) to connect with the Five Quarters mine which at this point

#365634