User:Ryan-is-Gneiss/Mine Dewatering
Mine dewatering is the action of removing groundwater from a mine. This has been a problem ever since we had to dig below the water table for resources. As technology is improved so does the techniques and prediction methods. This does not come without faults and there are many different problems that can occur and many different techniques to deal with the variety of situations that occur. (edited paragraph)
History
[edit]The act of taking water from a mine that is being operated has been done since Neolithic times. In the past it was done by using a shadoof, digging deeper dikes so that gravity would remove the water, by mounting leather water-filled buckets on water wheels or, if nothing else, carrying water-filled buckets manually. The Archimedes' screw was also historically used to pump water out of mines. Where no dewatering techniques were effective the mine had to be shut down due to flooding.
It was only in the 15th and 16th centuries that mine dewatering techniques had some technical advancements as the first mechanized pumps were made available, first in the German mine of Rammelsberg/Goslar, in the 15th century, and then in the also German mine of Ehrenfriedersdorf/Erzgebirge, in the 16th century.
With the dawn of the Industrial revolution, the demand for more coal also demanded more dewatering of the ever-deeper mines. Water was put in buckets and removed using rope conveyors powered by horses on treadmills.
Thomas Savery was the first to realize that a steam engine could be used to pump water out of mines, so he patented an early form of a steam engine. He described the device in his book The Miner's Friend; or, An Engine to Raise Water by Fire. His proposed engine however, was very ineffective and problematic in design. It could not pump water higher than 30 feet (9.1 m) above the water level.
The machina pyraulica, invented by Thomas Newcomen in 1712, combined the ideas of Thomas Savery, who he was forced to go into partnership with due to Savery's patent, and Denis Papin, using his invention of a piston. It was the first practical application of the steam engine and it was used to dewater coal and tin mines. The first reliable metal pump was created by József Károly Hell and used in the Schemitz mine in 1749. Almost 40 years later, in 1788, the first water-independent system appears that uses a metal pump. It was installed in the German lead and zinc mine of Tarnowitz.
Newcomen's design was later improved by James Watt in his steam engine, which doubled its efficiency.
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In the 20th century submersible pumps offered another innovation in mine dewatering. In the current days the dewatering techniques and systems are so advanced and well defined for each type of mine - open pit or underground - that even mines with thousands of meters deep can be successfully dewatered.
Modern day mines are planned for using computer models and simulations in order to account for estimation of damages and costs which improves the effectiveness of the mine dewatering techniques applied today as well as environmental evaluations[1]. This will also account for an estimation of damage that would be caused by groundwater contamination from the site. These models are often made with very specific assumptions of conditions for the surrounding environment and ground.
Dewatering a totally or partially flooded mine, or even as a normal procedure in normal mine activity, may carry a number of problems, most of which are environmentally related. This can happen in open pit mines as well as in underground mines[2]. Large problems are also developing with abandoned mines that have accumulated acid mine drainage that are growing to become a larger problem as the water sits in the mine and reacts with the exposed rock. There can be mitigated through proper management and with enough funds.
The most relevant concerns with mine dewatering are related to acid mine drainage and the dispersal of contaminated water into the surrounding water table and the general environment becoming a serious source of pollution[3]. This situation can occur in multiple ways such as bad practice of how the water is ejected and contained, lack of containment and equipment faults. A lot of these are directly or indirectly related to equipment malfunction from which results in drainage water being released into the environment[4]. One such way is the accumulation of water especially in deep water mines which could allow water to escape in the surrounding soil and water table.
Dewatering open pit mines and underground mines is different. Each method relies on different apparel and techniques.
For dewatering open mines the following are used:
- Filter wells
- Disposal wells
- Inverted wells
- Vacuum drainage
- Horizontal drains
- Sealing walls
- Cut off walls
- Guard wells
Underground, the following methods are used:
References
[edit]- ^ Yihdego, Yohannes; Drury, Len (2016-10-24). "Mine dewatering and impact assessment in an arid area: Case of Gulf region". Environmental Monitoring and Assessment. 188 (11): 634. doi:10.1007/s10661-016-5542-6. ISSN 1573-2959.
- ^ Oberholzer, Phillip Johannes (2015). Best practices for automation and control of mine dewatering systems (Thesis thesis).
- ^ Yihdego, Yohannes; Drury, Len (2016-10-24). "Mine dewatering and impact assessment in an arid area: Case of Gulf region". Environmental Monitoring and Assessment. 188 (11): 634. doi:10.1007/s10661-016-5542-6. ISSN 1573-2959.
- ^ Tammetta, Paul (2013). "Estimation of the Height of Complete Groundwater Drainage Above Mined Longwall Panels". Groundwater. 51 (5): 723–734. doi:10.1111/gwat.12003. ISSN 1745-6584.