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Types of Mining

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  1. [1]
    الصورة الرمزية احمد عباس الخطيب
    احمد عباس الخطيب
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    Types of Mining

    Types of Mining

    Placer

    Placer mining involves any type of mining
    where raw minerals are depostied in sand or gravel or on the surface and are picked up without having to drive, use dynamite or any other signifigant means. The word placer means "sand bank" in Spanish. Specific types of placer mining are panning, dredging, sluicing, using a Rocker, or just picking up what lies on the ground.

    Hydraulic
    Hydraulic mining involves high pressure water.
    The water is


    Operating hydraulic mining elevator and impounding works at North Bloomfield Mine
    sprayed at an area of rock and/or gravel and the water breaks the rock up, dislodging ore and placer deposits. The water/ore





    Hydraulic mining in Alder Gulch. Madison County, Montana.
    mixtue is then milled. This is a very destructive way to mine and has been outlawed in most areas.
    Hardrock
    Hardrock mining entails diging into solid rock to fine minerals usually in their ore form (the metal plus oxygen). To do this,
    miners used picks and shovels, rock drills,

    dynamite and more. Miners dug either shafts that went straight down to follow ore bodies and veins, or tunnels which went somewhat horizontal into rock faces. Shafts usually had some sort of headframe (pictured left) standing above them to support the hoists. Shafts and tunnels were often supported with large timbers to prevent cave-ins. Most shaft or tunnel mines would eventually flood as they hit the water table and water would have to be continually pumped out. Sometimes there was so much water they had to abandon the mines.
    Open Pit




    Open pit
    mines involve digging large open holes in the ground as opposed to a small shaft in hard rock mining. This method of mining is most often used with minerals like copper and molybdenum. Open pit mines are very large and devistate the surrounding landscape as can be seen in this picture of the Bingham Canyon Mine near Tooele, Utah. Mining operations of this scale were not done too often in the 19th century.

  2. [2]
    احمد عباس الخطيب
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    الصورة الرمزية احمد عباس الخطيب


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    Types of Hard Rock Mines

    Tunnels
    Hard rock mines usually fall into one of two categories, tunnels or shafts. Each involves digging and blasting deep into the bowels of the earth. Tunnel hard rock mines begin at the earth's surface


    Tunnel Mine
    and continue horizontally into the rock. Tunnels can extend for miles as they follow the ore. Most tunnels have many side tunnels, or even shafts that are sunk far back in the tunnel. These shafts are called winzes. Exploring Tunnel mines is very dangerous as it its dark and very difficult to see winzes. Many tunnels go back so far into the earth they tap into some of the earth's geothermal resources filling with gas that is toxic to humans. There is also the danger of cave-ins in old shafts that are no longer supported by the rotting wood timbers.
    Shafts
    A shaft is a whole in the earth that is dug relatively straight down. Shafts usually have some sort of headframe or large wooden or metal structure at the top of the shaft to support a hoist. Hoists are used to lower men and machinery into the mine and to haul


    Looking down a Shaft
    ore out. Many shafts have tunnels dug at different depths throughout the shaft. Getting too close to the side of an abandoned shaft can spell almost certain death. Many of the shafts extend thousands of feet into the earth.

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  3. [3]
    احمد عباس الخطيب
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    الصورة الرمزية احمد عباس الخطيب


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    Powering The Mines

    Steam Engines
    In the early days and in small operations, simple mule and man power was used for everything. As technology advanced, and operations became larger, the steam engine was introduced.

    A

    Steam Engine
    steam engine consisted of a large boiler. The boiler (pictured here) was a very large cylindrical metal chamber in which steam was produced. Most boilers have either fire tubes or water tubes on the inside of the chamber. Either water was forced through these tubes (pictured below) and the rest of the chamber was filled with "fire" or water filled the chamber and the tubes were filled with the "fire". Wood, coal or coke was used to produce the "fire" or heat that was in turn used to turn the water to steam. From the boiler, the steam went to a cylinder much like a modern gasoline powered car's cylinders. Under pressure, steam forced its way into the cylinder depressing the piston. As the piston was depressed, it turned a crankshaft which could be used to power a hoist, air compressors or pumps.
    Water(Hydro) Power
    Wherever possible, water or hydro power was used. If the location of the milling site was near any kind of sizeable reliable moving water, a water wheel would be used to generate power. This water wheel would have many paddles on it and would be partially submerged in moving water. As the water flowed, it would cause the wheel to turn. The wheel was then connected to whatever was needed to be powered.
    Diesel Engines
    In the early 1900's, diesel engines began to replace steam engines because they could produce more horsepower using less space. Invented by a man named Rudolph Diesel in 1894,

    Diesel Engine
    the diesel engine was built on the idea that air could get hot enough from the pressure inside the cylinder to ignited the fuel. A diesel engine does not have a spark plug. It generates the heat needed to ignite its fuel entirely from the compression of air. To do this, the compression in each cylinder is about 3 times the amount found in a normal gasoline engine. Diesel engines were hard to start as these engines were placed in harsh and many times cold locations where mines were located. To counteract this problem, glow plugs were used. These are small plugs located in the cylinder that can be electronically heated up to ignite the fuel when the engine is cold. Diesel engines are still used today to produce power at mines.

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  4. [4]
    احمد عباس الخطيب
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    Transporting the Ore
    From the Mine to the Outside World
    Once the ore was broken off the rock faces inside the mine, the chunks were shoveled into a transportation system to get it to the outside. If the mine was a shaft mine, the ore was shoveled into

    Ore Bucket
    an ore bucket which was hauled up to the top of the mine by a winch. This winch or hoist was usually powered by the

    Hoist
    steam or diesel engines and was also used to get the miners and other equipment in and out of the mines.

    Ore Car
    If the mine was a tunnel mine, the ore was shoveled into an ore car that ran on small train like track. The ore car was pulled on these tracks all the way out of the mine.
    From the Mouth of the Mine to the Mill
    Once the ore was at the mine entrance, it was transported to a mill for milling. The type of transportation used here depended on how far the mill was. Many mines had mills in the same town that were nearby the mine making transportation easy. Most of the time, ore was deposited into an ore chute that held tons of ore

    Ore Chute
    waiting to be processed. From this chute, the mill which was usually located below the chute to take advantage of gravity, took as much ore per hour as it could process. Sometimes the mines were located on steep cliffs or near the tops of mountains. In

    Aerial Tramway Tower
    these cases, an aerial tramway system was developed, much like a modern ski lift. The only difference is instead of carrying skiers on a seat the tramway carried ore in giant ore buckets. If the mill was located in another city or state, the ore was loaded onto sturdy wagons for transportation.
    From the Mill on
    Most mills were not able to concentrate the ore completely to the free metal. In other words, most mills located at the mines and townsites were not able to put a rock in one end and have a gold ingot come out the other. Their job was simply to concentrate the ore enough to save on the shipping. If the ore coming out of the mill was ten times more concentrated than the ore going in, then one wagon load of the processed ore would be equal to 10 wagon loads of the unprocessed ore. This could greatly reduce the riskiness and difficulty of shipping the ore as the ore wagons were a favorite of bandits.

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  5. [5]
    احمد عباس الخطيب
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    الصورة الرمزية احمد عباس الخطيب


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    Milling the Ore
    Arrastras
    When a full size stamp mill was not available, arrastras were used to crush the ore. Arrastras were small circular flat areas of land usually about 10-20 feet in diameter with a pole in the center.

    Early Arrastra
    Attached to the pole was a rod or line running out to a large heavy wheel. A horse or mule was usually attached to the end of the wheel area and would walk around in circles. As the animal walked, the heavy wheel would crush the ore underneath it. Arrastras were a crude way to crush large pieces of rock into much smaller and more manageable sized bits. In later years, iron arrastras (pictured on the right) replaced the wheel method.
    Stamp Mills
    Stamp Mills were far more advanced than the early arrastras although they both performed the same function. Stamp mills ranged from one stamp on up to twenty or even fifty stamps all operating together.

    5 Stamp Mill
    Each stamp was a large piece of solid iron or other metals attached to a long shaft. These shafts were usually attached to a cam with the other stamps if there were more than one. This cam had usually had a wheel on its end that was driven by a belt system. A steam engine was usually used to turn this wheel which lifted the stamps and dropped them with all their weight on the rocks that were to be crushed. Stamp mills would run 24 hours a day and as one can imagine, are extremely

    Small 3 Stamp Mill
    loud. They also tend to shake the ground as they are dropped which can make it feel like there is a continuous earthquake.

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  6. [6]
    احمد عباس الخطيب
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    عضو فعال جداً
    الصورة الرمزية احمد عباس الخطيب


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    Glossary
    ADIT: A horizontal or nearly horizontal entrance to a mine, otherwise known as a tunnel.
    ARRASTRA: A Spanish word for a circular rock-crushing device usually powered by a mule.
    ASSAY: Measuring proportion of gold or silver ******* in ore.
    CLAIM: A legal document stating the boundries of a proposed mining excavation.
    DREDGE: A mining process by which sand in a river bed or stream is scooped up from the bottom and minerals are extracted.
    FLOAT: Fragments of ore that had broken off a main vein to become buried rock outcropping.
    HEADFRAME: The vertical apparatus over a mine shaft that has cables to be lowered down the shaft for the raising and lowering of ore and men.
    HIGH GRADING: A method perfected by miners for carrying off rich ore from the mines and selling it themselves.
    HYDRAULIC MINING: A process of washing ore from its bed with powerfull jets of water.
    JUMPING A CLAIM: A method of taking over a good mining claim after it had already been staked out by someone else.
    MILL: A building in which rock is crushed in order to extricate minerals. Mills are usually constructed on the side of hills and are gravity fed. This leads to the stairstep foundations one can usually see.
    MOTHER LODE: The main or primary deposit or vein of a given mineral.
    NUGGET: A lump of native or pure gold found in deposits and placer mines.
    PLACER: A waterborne deposit of sand or gravel containing heavier minerals like gold that have been eroded from their original bedrock and concentrated as small particles that can be washed out.
    PLATTING: Planning or mapping a townsite.
    SHAFT: A vertical or nearly vertical opening into the Earth's surface.
    SLUICE: an inclined trough, usually made of wood, for washing gold ore. The flow of the water is regulated by flood gates.
    SMELTER: A building or complex in which material is melted to be separated from impurities.
    STAMP MILL: A machine that crushes rock by means of a big heavy stamp that falls on the rock.
    TAILINGS: Waste or refuse left after milling is complete, sometimes referred to as waste dumps.
    WASTE DUMP: Waste rock that comes out of a mine.
    WINZE: A shaft sunk from an adit.

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  7. [7]
    mjcoolz21
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    جديد


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    thanks for your explain with picture..its so helpfull me to understanding my lecture

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