Shale oil extraction technique and heavy metals, uranium gold, silver, platinum, etc., see diamonds!
Officialy exploitation by oil hydraulic fracturing is the fact soils to drill 2 km deep vertically then horizontally and use very powerful pumps and vacuums to fracture the rocks of mercury and sometimes acids or nuclear explosive other types as it involves treating some rocks on the surface to grind into fine dust that are rocks that look like slate and place in centrifuges like the truck with rotating concrete mixers can extract oil but actually it can also extract native gold depths because gold is heavy it tends to sink into the earth's crust as uranium diamonds etc !!! brief concludes exploitation of shale gas requires the even modern equipment for extracting gold and silver and the same chemicals to agglomerate gold dust or mercury money centrigugeuses of acids that can help discreetly to fly mineral wealth of a country of more the industry can cause earthquakes see the end of the world! Because we fracture the rock mother!
The hydraulic fracturing (or fracking) 9 is to cause prior to production of the well a large number of micro-fractures (of the order of a millimeter) in the rock containing gas, making it porous and allows the gas or shale oil to move to the well to be recovered at the surface. Fracturing is achieved by the high-pressure injection of water (about 300 bar to 2500 meters deep) in the geological formation through the horizontal well 10 . The water which is injected contains various additives11 to improve the efficiency of the fracturing:
- the sand of particle size suitable, will creep into micro-fractures and prevent them close again;
- of biocides to reduce bacterial growth in the fluid and in the well;
- of lubricants which promote the penetration of sand into the micro-fractures open by the water pressure;
- of detergents that enhance the desorption of the gas and therefore the productivity of wells.
The fracturing is carried out upon completion of drilling. It is carried out in several stages, the number is even more important that the rock is impermeable. On average, for a horizontal well length of one kilometer, it takes 30 operations fracturing each consuming about 300 m3 of water, 30 tons of sand and 0.5% additives (figures provided by the oil company Total ) 5 , 8 .
The development of a reservoir begins with a phase of geological, geophysical and eventually achieving exploration drilling. The start of production of shale gas wells begins with the installation of a derrick with a footprint of approximately 1 hectare. A vertical well is drilled to reach the reservoir. The sealing of the vertical portion of the well which plays a critical role in the absence of contamination of the groundwater is carried out by steel casing device (casing) then cementing the space between the rock and the casing. Drilling the horizontal section of the well which can extend out of 1 2 kilometers lasts from 4 to 8 weeks. The trajectory of the drill head, which is inclinable and guided from the surface, is known through instruments including based on inertial systems and magnetic field measurement. A casing is then installed in the horizontal portion of the well then perforated using explosive charges of a few grams to enable the collection of natural gas. Drilling rigs are then dismantled. Phase fracturing following generally lasting several days. Once completed, the injected water is pumped and stored at the surface before being reprocessed. The well comes into production: this phase, which can last ten years can be completely passive; However, the fracturing operation may be repeated in order to reactivate the crack network when production decreases (multifracking) 5 , 8 . As in a conventional drilling operation after the completion of the drilling is closed with cement plugs measuring between 50 and 100 m thickness at several different levels.
In summary, the main differences of the gas extraction process and shale oil compared to conventional deposits are 5 :
- the gas is not concentrated in a diffuse but permeable reservoir rock in the rock artificially made permeable to a small distance around the well. Therefore a well drains a small volume of rock and brings relatively little gas. To produce the same amount of gas, multiply the wells which requires, for the same amount of gas produced, significantly more investment.
- the injected amount of water (volume several hundred times larger than the conventional gas extraction) requires particularly large reprocessing plants and can create conflicts with other users (farmers ...)
- the production curve is characterized by a pronounced peak but short in early life and then rapidly decline to low threshold without intermediate plate (explained in point 1). This feature requires the multiplication of wells.
- the recovery rate of a shale gas field is currently an average of 20% against 75% for conventional gas deposits.
- Metallurgy [ edit | edit the code ] Extraction methods [ edit | edit the code ]
The extraction of the gold is divided into several phases:
- mining of ore ;
- concentration of gold, by gravitation or by emission of foam;
- leaching (leaching) by means of cyanide ;
- removal of mercury by precipitation (Merrill-Crowe processing);
- Removal of iron by treatment with nitric acid ;
- fusion ;
- Various methods of residual gold extraction solution (in mining and industrial effluents) are tested for several decades; by BCF , or better yet by biosorption example from necromass ofAzolla filiculoides (small floating fern); in the latter case, it exceeded 99% yield in the best conditions 39 , 40 . Previously we had tested a necromass algal 41 for different types of dissolved gold 42 as biosorbent 43 , 44 ; By passing the water containing dissolved gold on a bed of previously harvested Azolla in nature, washed with distilled water and dried at 37 ° C, the Azolla biomass has shown itself capable of "capture" and set to 86% to 100% of the gold (III) present in a solution that initially contained February to October mg · l-1 39 . In this case, the initial gold concentration was 8 mg · l-1 and 5 g of dried Azolla filiculoides were added per liter of solution (the medium being stirred by a stirrer). The authors concluded that the dried Azolla is a " biosorbent "very effective, since it presents a" sequestering power "exceeding that of expensive and polluting ion exchange resins commercially available or that of the activated charcoal 39 .
- Gold panning [ edit | edit the code ] cyanidation [ edit | edit the code ] Mines and EnvironmentWaste and Pollution Ore processing non-metallic minerals Metal ores
The gold forms an amalgam with the mercury , which allows the extraction of the mineral matrix. The amalgam of gold and mercury is heated, mercury evaporates and the gold is deposited. The use of mercury to amalgamate gold can have serious consequences ecologicaland health 45 .
In Guyana , the operations Anaconda and Harpy aim to combat illegal gold mining.
The ore is first crushed and ground, passed through a flotation unit providing a concentrated and residue placed in heap (dumps) containing gold and other metals 46 .
The concentrate of the processing is performed by cyanide which comprises dissolving the ore in a solution of alkali metal cyanides. Gold is then precipitated by addition of a chemical reagent, and then filtered.
This process will probably be replaced by extracting gold from ore or its recovery in the electronics discarded by the process discovered by Liu Zhichang Team Fraser Stoddart (chemist at Northwestern University ) and lead author of the study published May 14, 2013 in the journalNature Communications 47 . He mixed the contents of two test tubes: one contained alpha-cyclodextrin , the other a solution containing gold, and thus obtained tiny needles in the mixture, constituted by an assembly of some 4 000 nano-son of gold ions held by carbon, water andcyclodextrin , this sorting or other precious metals present in the ore, such as palladium orplatinum .
"The elimination of cyanide in the gold industry is of the utmost importance for the environment. We replaced these terrible substances by a cheap material, biologically harmless, derivative of starch " 48 .
The metals are extracted from the ore by heating or by chemical solvents. Both processes release large amounts of toxic materials that may have a greater environmental impact than mining itself. Here are two examples:
- Roasting the ore
The ore roasting is a major source of air pollution. One of the most famous examples of ecological devastation is that of Ducktown, Tennessee. By the mid 1800s the mining companies began to exploit the rich copper deposits in the region. To extract the copper from the ore they established very large wood fires in the open air, using the wood from nearby forests. Dense clouds of sulfur dioxide not released sulfides poisoned vegetation and acidified the soil on more than 13,000 hectares. The rains have removed the ground of the earth bare, creating a lunar landscape where nothing could grow.
Sulphur emissions have been reduced from 1907 by the vote of air pollution control laws.From 1930 began the soil and replanting treatment efforts. Recently up to $ 250,000 per year was spent on the restoration. While the trees and plants are still sparse and rickety one considers that currently two-thirds of the surface were so "adequate" revegetated.
- Extraction with chemical solvents
The chemical extraction is used to dissolve or mobilize the elements in the powdered ore and pollutes but uses a large amount of water. A common method for extraction of gold ore is irrigation stacks sprayed with a dilute solution of alkali metal cyanides.
The solution percolates through the stack and dissolved gold. This solution is then pumped to an industrial unit that recovers or by electrolysis. A thick layer of clay and a plastic sheet under the ore piles are supposed to prevent the cyanide solution contaminates the soil or groundwater, but leaks are common.
When a mine is exhausted mining companies can simply lift the foot, leaving large volumes of toxic waste in open ponds. For example a Colorado mine after mining gold worth $ 98 million, was declared bankrupt in 1992, leaving millions of tons of rubble and huge pools of cyanide fleeing. It will spend more than $ 100 million to clean up the site and prevent basins emptying into the nearby river.
In 2000 a very big cyanide spill from a Romanian gold mine has poisoned millions of fish and put out of the water treatment plants of 640 km long along the rivers Szamos, Tisza and Danube , Hungary and Yugoslavia.
Non-metallic deposits being very varied nature and composition also will cause, in addition to general disturbances related to mining environmental impact of very specific natures.
The Alsatian potash deposit is a good example of environmental damage related to the processing of non-metallic minerals.
It was formed in the Oligocene (26 to 38 million years) in a lagoon fed periodically into new waters by playing a "bar." Within sylvinite layers, alternating sylvite (KCl), rock salt (NaCl) correspond to seasonal changes, KCl accumulating in the cold season, warm season NaCl.
Discovered in 1904, located in the Alsace plain, northwest of Mulhouse, it covers approximately 20,000 hectares.
It consists of two layers separated by 20 m from rock salt, marls and anhydrite (CaSO4) located at depths ranging from 400 to 1100 m.
- Lower layer (the most powerful): thickness from 3 m and 5.50 m, the training lasted 160 years.
- Top layer of thickness between 1 and 2.20 m formed for about 30 years.
Each layer is composed of alternating threads (thick variant mm cm), KCl, NaCl and clay.
The ore (sylvinite) has a content of 25% sylvite, rock salt 60% and 15% of insoluble elements (clay ...). It also contains KBr that is recovered and recovered to produce bromine
- Roasting the ore